Immunotherapies targeting the programmed cell death-1 ligand 1 (PD-L1) and programmed cell death 1 (PD-1) pathway sparked a revolution in cancer treatment. These breakthrough therapies work by disrupting the interaction between PD-1-expressed on T cells-and its ligand PD-L1, commonly found on the surface of cancer cells. By using monoclonal antibodies to block this binding, the immune system is unleashed to fight cancer more effectively. However, PD-L1's role extends far beyond immune evasion. When situated on cancer cells, PD-L1 transmits inhibitory signals through PD-1, silencing the effector functions of T cells. However, PD-L1 also engages in reverse signaling, also called intrinsic signaling, delivering intracellular instructions that contribute to cancer cell survival, even in the absence of PD-1 binding. This signaling cascade shields cancer cells from apoptosis, drives proliferation, regulates DNA damage responses, and even functions as a co-transcriptional transactivator, amplifying cancer's ability to thrive. The intricate mechanisms behind PD-L1's intrinsic signaling are under intense investigation. In this review, we provide a historical perspective on the discoveries leading to PD-L1's structure, signaling motifs, and interacting partners, shedding light on its multifaceted roles and the promising therapeutic possibilities ahead.

P4HA2 is implicated in regulating tumor microenvironment formation and may play roles in inflammation and tumor immunity. However, its mechanistic involvement in colorectal cancer (CRC) remains largely unexplored.

We analyzed P4HA2 expression in CRC tissues and correlated it with clinicopathological features. Functional assays (CCK8, wound healing, Transwell) were performed to assess proliferation and migration. Proteomic analysis identified downstream targets, with STAT1/PD-L1 pathway validation.

High P4HA2 expression correlated with advanced T/M stages and served as an independent poor prognostic factor. Functional experiments confirmed P4HA2's role in promoting CRC proliferation and migration. Mechanistically, P4HA2 bound to and downregulated STAT1, subsequently modulating the STAT1/PD-L1 pathway.

Our findings reveal P4HA2 promotes CRC progression and suppresses anti-tumor immunity via STAT1/PD-L1 axis regulation. This study uncovers a novel pathogenic mechanism, positioning P4HA2 as a potential therapeutic target in CRC.

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the United States. A key driver of CRC development is microsatellite instability (MSI), which is caused by DNA mismatch repair deficiency and characterized by hypermutability of short-tandem repeat sequences. A significant portion of MSI CRCs do not respond to checkpoint immunotherapy treatments, highlighting an unmet need for improved therapies. Recent studies have revealed that MSI cancer cells require Werner (WRN), a RecQ family DNA helicase, for survival. Inhibiting WRN has emerged as a promising approach for targeting MSI CRCs that are insensitive to standard therapies. Several highly potent small-molecule WRN inhibitors have been developed and exhibited striking in vitro and in vivo activities against MSI cancers. Two of these WRN inhibitors, HRO761 and VVD-133214, have recently entered clinical trials. In this review, we summarize recent studies on WRN as a synthetic lethal target in MSI CRC and the development of WRN inhibitors as a new class of anticancer agents.

The development of immune checkpoint inhibitors has revolutionized the treatment of patients with cancer. Targeting the programmed cell death protein 1 (PD-1)/programmed cell death 1 ligand 1(PD-L1) interaction using monoclonal antibodies has emerged as a prominent focus in tumor therapy with rapid advancements. However, the efficacy of anti-PD-1/PD-L1 treatment is hindered by primary or acquired resistance, limiting the effectiveness of single-drug approaches. Moreover, combining PD-1/PD-L1 with other immune drugs, targeted therapies, or chemotherapy significantly enhances response rates while exacerbating adverse reactions. Multispecific antibodies, capable of binding to different epitopes, offer improved antitumor efficacy while reducing drug-related side effects, serving as a promising therapeutic approach in cancer treatment. Several bispecific antibodies (bsAbs) targeting PD-1/PD-L1 have received regulatory approval, and many more are currently in clinical development. Additionally, tri-specific antibodies (TsAbs) and tetra-specific antibodies (TetraMabs) are under development. This review comprehensively explores the fundamental structure, preclinical principles, clinical trial progress, and challenges associated with bsAbs targeting PD-1/PD-L1.

Recently, neoantigen (NA) profiling has been intensively performed for the development of novel immunotherapy. We previously reported a melanoma case with a high tumor mutation burden that achieved complete remission after anti-programmed death-1 therapy. We herein revisited the same case, characterized the NA profiles of other metastatic lesions using in silico algorithms and in vitro CTL assays, and investigated the immunological status, including tumor-infiltrating lymphocytes and the T cell receptor (TCR) repertoire profile, in metastatic sites.

NA candidates obtained from whole-exome sequencing were applied to the HLA-binding prediction algorithm, NetMHCpan4.1. HLA-A*2402-restricted sequence candidates with a strong binding capacity (<50 nM) and elution affinity (<1%) were selected and evaluated for synthetic peptide candidates. The immunological status in metastatic sites was characterized using gene expression profiling, immunohistochemistry, and a TCR repertoire analysis.

The genomic analysis revealed that all metastatic sites, such as costal, intra-muscular, and brain lesions, had >1,500 SNVs, and 12 driver mutations were common to all sites. New driver mutations were identified in intra-muscular (KMT2C: p.P3292S) and brain (JAK1: p.S404P) metastases and a functional analysis of these mutations revealed that JAK1 mutation exhibited a promoting effect on invasion activity. CTL assays using synthetic NA peptides identified more NA epitopes in brain metastasis.

These results might suggest that the heterogeneity of driver gene mutations is unremarkable, while immunological response is variable in metastatic sites. As a result, the genomic and immunological investigation has provided a very valuable and informative suggestion regarding better cancer therapy decisions.

Patients have a limited response rate to immune checkpoint inhibitors (ICIs) therapy. Although several biomarkers have been proposed, their ability to accurately predict the response to ICIs therapy remains unsatisfactory. In addition, mutational signatures were validated to be associated with ICIs therapy. Therefore, we developed a mutational signature-based biomarker (MS-bio) to predict the response to ICIs therapy. Based on differentially mutated genes, we extracted six mutational signatures (single-base substitution (SBS)-A, SBS-B, SBS-C, SBS-D, double-base substitution (DBS)-A, and DBS-B) as MS-bio, and constructed a random forest (RF) model to predict the response. Internal and external validations consistently demonstrated the excellent predictive capability of MS-bio, with an accuracy reaching up to 0.82. Moreover, MS-bio exhibited superior performance compared to existing biomarkers. To further validate the accuracy of MS-bio, we explored its performance in The Cancer Genome Atlas (TCGA) cohort and found that the predicted responders were immunologically "hot". Finally, we found that SBS-C had the highest importance in prediction and was related to T cell differentiation. Overall, here we introduced MS-bio as a novel biomarker for accurately predicting the response to ICIs therapy, thereby contributing to the advancement of precision medicine.

The JAK pathway is central to mammalian cell communication, characterized by rapid responses, receptor versatility, and fine-tuned regulation. It involves Janus kinases (JAK1, JAK2, JAK3, TYK2), which are activated when natural ligands bind to receptors, leading to autophosphorylation and activation of STAT transcription factors [1, 2]. JAK-dependent signaling plays a pivotal role in coordinating cell communication networks across a broad spectrum of biological systems including development, immune responses, cell growth, and differentiation. JAKs are frequently mutated in the aging hematopoietic system [3, 4] and in hematopoietic cancers [5]. Thus, dysregulation of the pathway results in various diseases, including cancers and immune disorders. The binding of extracellular ligands to class I and II cytokine receptors initiates a critical signaling cascade through the activation of Janus kinases (JAKs). Upon ligand engagement, JAKs become activated and phosphorylate specific tyrosine residues on the receptor, creating docking sites for signal transducer and activator of transcription (STAT) proteins. Subsequent JAK-mediated phosphorylation of STATs enables their dimerization and nuclear translocation, where they function as transcription factors to modulate gene expression. Under physiological conditions, JAK-signaling is a tightly regulated mechanism that governs cellular responses to external cues, such as cytokines and growth factors, ensuring homeostasis and maintaining the functional integrity of tissues and organs. Highly defined regulation of JAK-signaling is essential for balancing cellular responses to inflammatory stimuli and growth signals, thus safeguarding tissue health. In contrast, dysregulated JAK-signaling results in chronic inflammation and unrestrained cellular proliferation associated with various diseases. Understanding the qualitative and quantitative differences at the interface of physiologic JAK-signaling and its aberrant activation in disease is crucial for the development of targeted therapies that precisely tune this pathway to target pathologic activation patterns while leaving homeostatic processes largely unaffected. Consequently, pharmaceutical research has targeted this pathway for drug development leading to the approval of several substances with different selectivity profiles towards individual JAKs. Yet, the precise impact of inhibitor selectivity and the complex interplay of different functional modules within normal and malignant cells remains incompletely understood. In this review, we summarize the current knowledge on JAK-signaling in health and disease and highlight recent advances and future directions in the field.

Radiotherapy, although widely used for cancer therapy, always triggers changes in tumor microenvironment (TME) that lead to radioresistance and immunosuppression. In particular, during X-ray irradiation, hypoxia exacerbation would reduce radiosensitivity of tumor cells, while programmed cell death ligand 1 (PD-L1) upregulation impairs antitumor immune responses and exacerbates DNA damage repair, collectively resulting in severe T cell exhaustion and unsatisfactory therapeutic effect. Herein, we developed a liposomal nanodrug, C/J-LipoRGD, to simultaneously encapsulate a biological enzyme and a bromodomain containing 4 (BRD4) inhibitor for tumor-targeting delivery and TME modulation. Among C/J-LipoRGD, catalase could catalyze the decomposition of the excess H2O2 in tumors and improve TME oxygenation. Meanwhile, JQ1 as a BRD4 inhibitor after being taken by cancer cells could downregulate PD-L1 expression in both cellular membrane and cytosol, inhibiting PD-1/PD-L1 interaction and DNA damage repair. By alleviating hypoxia and downregulating PD-L1 expression, C/J-LipoRGD reverses T cell exhaustion in TME. Altogether, C/J-LipoRGD-based radiotherapy significantly inhibited tumor growth and meanwhile triggered immunogenic cell death (ICD) of cancer cells to activate T cell-mediated anti-tumor immunity. After the combination with αPD-1, C/J-LipoRGD-based radio-immunotherapy achieved complete tumor eradication and metastases elimination in 80 % mice with survival over 80 days. This multifunctional nanodrug represents a promising strategy to overcome therapy resistance and optimize radio-immunotherapy outcomes.

Acquired resistance to immunotherapy (ARI) is a major challenge in solid tumors, limiting long-term success in up to 65% of patients who initially respond to immunotherapy. Defining ARI clinically remains complex, but ongoing efforts aim to establish standardized criteria. This review describes recent insights into ARI, revealing complex mechanisms involving both tumor-intrinsic mechanisms - such as antigen loss and presentation defects, interferon γ (IFNγ) insensitivity, tumor-mediated T cell exclusion, and metabolic reprogramming - as well as extrinsic factors such as inhibitory molecule upregulation, immunosuppressive cells, extracellular matrix (ECM) remodeling, and dysbiotic microbiota. Understanding the development of ARI is crucial for prevention and effective interventions. The integration of innovative strategies and translational research on appropriately collected samples is key to overcoming ARI and ensuring durable benefits for patients.

Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control. Over the last decade, much effort has been directed at characterizing factors that drive efficacy and resistance to ICI therapy. Food and Drug Administration (FDA)-approved biomarkers for ICI therapy have facilitated more judicious treatment of cancer patients and transformed the field of precision oncology. Yet, adaptive immunity against cancers is complex, and newer data have revealed the potential utility of other biomarkers. In this review, we discuss the utility of currently approved biomarkers and highlight how emerging biomarkers can further improve the identification of patients who benefit from ICIs.

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide, with increasing incidence in younger ages highlighting the need for new or alternative therapy, of which is immune checkpoint inhibitors. Antibody-based immune checkpoint inhibitors targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have revolutionized cancer treatment, including CRC. However, the low response rate in CRC highlights the need for additional research and innovative therapies. Small molecule inhibitors have risen as another strategy worth exploring, considering their potential to target a wide array of PD-1/PD-L1-related pathways. This review focuses on the potential of small molecule inhibitors targeting the PD-1/PD-L1 axis in CRC. Exploring various classes of small molecule inhibitors, including those that directly block the PD-1/PD-L1 interaction and others that target upstream regulators or downstream signaling pathways involved in PD-1/PD-L1-mediated immune suppression. Additionally, modulation of post-transcriptional and post-translational processes, thereby influencing the expression, stability, or localization of PD-1/PD-L1 proteins to enhance antitumor immunity, provides a multifaceted treatment approach. By disrupting these pathways, these inhibitors can restore immune system activity against tumor cells, offering new hope for overcoming resistance and improving outcomes in CRC patients who do not respond to conventional immune checkpoint inhibitors (ICIs). Integrating these small molecules into CRC treatment strategies could represent a promising advancement in the battle against the challenging disease.

Insufficient tumor cell-intrinsic interferon response represents a major obstacle in immune checkpoint blockade (ICB) therapy, particularly in anti-PD-1 treatment. Although cholesterol metabolism has been demonstrated to be a critical regulator of anti-tumor immune responses, whether cholesterol influences tumor cell-intrinsic interferon response in microsatellite instability (MSI) colorectal cancer (CRC) remains unknown. Through comprehensive siRNA library screening and Gene Set Enrichment Analysis (GSEA), we identified mevalonate kinase (MVK) as a crucial negative regulator of tumor cell-intrinsic interferon response in MSI CRC cells. Genetic ablation of MVK resulted in significant upregulation of Th1 type chemokines (CXCL9 and CXCL10) and enhanced CD8+T cell infiltration in MSI CRC, consequently leading to marked tumor growth suppression in immunocompetent mice. At the molecular level, we demonstrated that MVK physically interacts with the transcriptional activation domain (TAD) of signal transducer and activator of transcription 1 (STAT1). This interaction substantially impairs STAT1 nuclear translocation, thereby attenuating interferon signaling cascade. Furthermore, analyses of humanized PBMC-PDX models and clinical cohorts of MSI CRC patients revealed that reduced MVK expression in tumor tissues strongly correlates with favorable responses to anti-PD-1 therapy. Collectively, our findings establish MVK as a pivotal mediator in cholesterol synthesis pathway that negatively regulates tumor cell-intrinsic interferon response in MSI CRC. These results suggest that therapeutic targeting of MVK represents a promising strategy to enhance ICB efficacy through potentiation of interferon responses in MSI CRC patients.

The IFN-γ cytokine plays a dual role in anti-tumor immunity, enhancing immune defense against cancer cells while promoting tumor survival and progression. Its influence on prognosis and therapeutic responses across cancer types remains unclear.

This study aimed to perform a pan-cancer analysis of IFN-γ response genes to determine their prognostic significance and evaluate their impact on clinical outcomes and anti-PD1 immunotherapy responses.

Using multiple datasets, 46 IFN-γ response genes were identified as prognostic for disease-specific survival, and their expression was used to construct the IFN-γ Response Gene Network Signature (IFGRNS) score. The prognostic and therapeutic relevance of the IFGRNS score was assessed across cancer types, considering tumor pathology, genomic alterations, tumor mutation burden, and microenvironment. Single-cell transcriptomic analysis identified cellular contributors, and a murine pancreatic cancer (PAN02) model was used to validate findings with anti-PD1 therapy.

The IFGRNS score emerged as a robust prognostic indicator of survival, with higher scores correlating with worse outcomes in most cancer types. The prognostic significance of the score was influenced by factors such as cancer type, tumor pathology, and the tumor microenvironment. Single-cell analysis revealed that myeloid cells, particularly the M2 macrophage subtype, demonstrated high levels of IFGRNS expression, which was associated with tumor progression. A negative correlation was observed between the IFGRNS score and outcomes to anti-PD1 immunotherapy in urologic cancers, where patients with higher scores showed worse prognosis and lower response rates to therapy. Experimental validation in the PAN02 murine model confirmed that anti-PD1 therapy significantly reduced tumor size and IFGRNS expression in M2 macrophages, supporting the clinical findings.

The IFGRNS score is a novel prognostic indicator for survival and therapeutic responses in cancer. These findings underline the complexity of IFN-γ signaling and suggest potential applications for the IFGRNS score in cancer diagnosis, prognosis, and immunotherapy. Novelty & impact statements: IFN-γ response genes play a significant role in tumour biology, yet comprehensive analysis across various cancers is limited. This study identifies a novel prognostic biomarker, the IFGRNS score, which is elevated in myeloid lineage cells and correlates with survival across multiple cancers. The IFGRNS score is also associated with tumour pathology, immune microenvironment, and immunotherapy response, highlighting its diagnostic and therapeutic potential in cancer management.

IFN-γ cytokine plays a dual role in cancer, aiding immune defense but also promoting tumor progression. A novel IFGRNS score, based on 46 IFN-γ response genes, was identified as a strong prognostic marker for survival across cancer types. Higher IFGRNS scores correlate with worse prognosis and reduced response to anti-PD1 immunotherapy, particularly in urologic cancers. M2 macrophages were identified as key contributors to high IFGRNS scores, associated with tumor progression. Findings were validated in a murine cancer model, highlighting the potential of the IFGRNS score for cancer prognosis and therapy guidance.

Interferon-gamma (IFN-γ) is a cytokine produced mainly by immune cells and can affect cancer cells by modulating the activity of multiple signaling pathways, including the canonical Janus-activated kinase/signal transducer and activator of transcription (JAK/STAT) cascade. In melanoma, IFN-γ can exert both anticancer effects associated with cell-cycle arrest and cell death induction and protumorigenic activity related to immune evasion leading to melanoma progression. Notably, IFN-γ plays a crucial role in the response of melanoma patients to immunotherapy with immune checkpoint inhibitors (ICIs), which are currently used in the clinic. As these agents target programmed death-1 (PD-1) and its ligand (PD-L1), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and lymphocyte-activation gene 3 (LAG-3), they are designed to restore the antimelanoma immune response. In this respect, IFN-γ produced by cells in the tumor microenvironment in response to ICIs has a beneficial influence on both immune and melanoma cells by increasing antigen presentation, recruiting additional T-cells to the tumor site, and inducing direct antiproliferative effects and apoptosis in melanoma cells. Therefore, IFN-γ itself and IFN-γ-related gene signatures during the response to ICIs can constitute biomarkers or predictors of the clinical outcome of melanoma patients treated with ICIs. However, owing to its multifaceted roles, IFN-γ can also contribute to developing mechanisms associated with the acquisition of resistance to ICIs. These mechanisms can be associated with either decreased IFN-γ levels in the tumor microenvironment or diminished responsiveness to IFN-γ due to changes in the melanoma phenotypes associated with affected activity of other signaling pathways or genetic alterations e.g., in JAK, which restricts the ability of melanoma cells to respond to IFN-γ. In this respect, the influence of IFN-γ on melanoma-specific regulators of the dynamic plasticity of the cell phenotype, including microphthalmia-associated transcription factor (MITF) and nerve growth factor receptor (NGFR)/CD271 can affect the clinical efficacy of ICIs. This review comprehensively discusses the role of IFN-γ in the response of melanoma patients to ICIs with respect to its positive influence and role in IFN-γ-related mechanisms of resistance to ICIs as well as the potential use of predictive markers on the basis of IFN-γ levels and signatures of IFN-γ-dependent genes.

Anti-PD-1/PD-L1 immune checkpoint blockade (ICB) therapy has revolutionized clinical cancer treatment, while abnormal PD-L1 or HLA-I expression in patients can significantly impact the therapeutic efficacy. Somatic mutations in cancer cells that modulate these critical regulators are closely associated with tumor progression and ICB response. However, a systematic interpretation of cancer immune-related mutations is still lacking. Here, we harnessed the ABEmax system to establish a large-scale sgRNA library encompassing approximately 820,000 sgRNAs that target all feasible serine/threonine/tyrosine residues across the human genome, which systematically unveiled thousands of novel mutations that decrease or augment PD-L1 or HLA-I expression. Beyond residues associated with phosphorylation events, our screens also identified functional mutations that affect mRNA or protein stability, DNA binding capacity, protein-protein interactions, and enzymatic catalytic activity, leading to either gene inactivation or activation. Notably, we uncovered certain mutations that concurrently modulate PD-L1 and HLA-I expression, represented by the clinically relevant mutation SETD2_Y1666. We demonstrated that this mutation induces consistent phenotypic effects across multiple cancer cell lines and enhances the efficacy of immunotherapy in different tumor models. Our findings provide an unprecedented resource of functional residues that regulate cancer immunosurveillance, offering valuable guidance for clinical diagnosis, ICB therapy, and the development of innovative drugs for cancer treatment.

Cellular senescence, defined as a state of permanent arrest in cell growth, is regarded as a crucial tumor suppression mechanism. However, accumulating scientific evidence suggests that senescent cells play a detrimental role in the progression of cancer. Unfortunately, the current lack of reliable markers that specifically reflect the level of senescence in cancer greatly hinders our in-depth understanding of this important biological foundation. Therefore, the search for more specific and reliable markers to reveal the specific role of senescent cells in cancer progression is particularly urgent and important. To uncover the role of senescence in gliomas, we collected senescence-related genes for integrated analysis. Consensus clustering was used to subtype gliomas based on the senescence gene set, and we identified two robust prognostic clusters of gliomas with distinct survival outcomes, multi-omics landscapes, immune characteristics, and differential drug responses. Multiple external datasets were used to validate the stability of our subtypes. Various computational and experimental methods, including WGCNA (Weighted Gene Co-expression Network Analysis), ssGSEA (single-sample Gene Set Enrichment Analysis), and machine learning algorithms (lasso regression, support vector machines, random forests), were employed for analysis. We found that CEBPB and LMNA are associated with poor prognosis in gliomas and may mediate immunosuppression and tumor proliferation. Drug prediction indicated that dasatinib is a potential therapeutic agent. Our findings provide insights into the role of the senescence gene set in patient stratification and precision medicine.

The tumor microenvironment (TME) contains tumor cells, surrounding cells, and secreted factors. It provides a favorable environment for the maintenance of cancer stem cells (CSCs), the spread of cancer cells to metastatic sites, angiogenesis, and apoptosis, as well as the growth, proliferation, invasion, and drug resistance of cancer cells. Cancer cells rely on the activation of oncogenes, inactivation of tumor suppressors, and the support of a normal stroma for their growth, proliferation, and survival, all of which are provided by the TME. The TME is characterized by the presence of various cells, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), CD8 + cytotoxic T cells (CTLs), regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), mesenchymal stem cells (MSCs), endothelial cells, adipocytes, and neuroendocrine (NE) cells. The high expression of inflammatory cytokines, angiogenic factors, and anti-apoptotic factors, as well as drug resistance mechanisms in the TME, contributes to the poor therapeutic efficacy of anticancer drugs and tumor progression. Hence, this review describes the mechanisms through which the TME is involved in apoptosis, angiogenesis, metastasis, and drug resistance in tumor cells.

Interferon-γ (IFN-γ) is a key mediator in antitumor immunity and immunotherapy responses, yet its clinical applications remain restricted to chronic granulomatous disease and malignant osteopetrosis. IFN-γ effectiveness as a standalone treatment has shown limited success in clinical trials and its potential for synergistic effects when combined with immunotherapies is under clinical exploration. A particularly compelling combination is that of IFN-γ with Toll-like receptor (TLR) agonists that holds significant promise for cancer treatment. Previously, we demonstrated chitosan (Ch)/poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs), known to activate TLRs, as adjuvants to radiotherapy by remodeling breast tumor microenvironment and systemic immunosuppression. These immunomodulatory abilities make Ch/γ-PGA NPs promising adjuvants to IFN-γ-based therapies. Here, we addressed the synergistic therapeutic potential of combining Ch/γ-PGA NPs with IFN-γ therapy in the 4T1 orthotopic breast tumor mouse model. While control animals (placebo-treated) had progressive tumor growth and lung metastases, those treated with either NPs or IFN-γ alone had a significant slower tumor growth. Remarkably, primary tumor growth was halted throughout the duration of the treatment when both treatments were combined. Although the animals did not achieve durable complete responses upon treatment withdrawal, it was notable that the NPs plus IFN-γ group presented a lower lung metastatic burden compared to other groups. Systemically, the combination therapy slightly attenuated immunosuppression and the percentage of splenic myeloid cells, while increased the percentage of T helper 1 cells and of cytotoxic T cells. Overall, this proof-of-concept study suggests that Ch/γ-PGA NPs potentiate IFN-γ effects to reduce tumor progression, presenting a novel approach for anticancer strategies.

Reducing the number of immunosuppressive cells in blood is a potential strategy for activating anti-tumor immunity, which provides a promising approach to cancer treatment. In this study, we developed an adsorbent designed to selectively target and adsorb lymphocytes expressing latency-associated peptide (LAP), which is abundantly expressed on the surface of CD4+ regulatory T cells (Tregs) and CD14+ monocytes. We investigated whether diethylenetriamine-conjugated polysulfone adsorbent-based direct hemoperfusion (DHP) enhances anti-tumor immunity in a rat cancer model with KDH-V liver cells. Our findings revealed that DHP significantly reduced LAP+ Tregs in both peripheral blood and tumor tissues in treated mice. Consequently, cytotoxic T-lymphocytes increased in tumor-bearing rats. The anti-tumor effect was negated by the addition of cells detached from the absorbent, indicating that these cells play a crucial role in inhibiting the observed therapeutic effect. The results suggest that depleting LAP+ immunosuppressive cells in blood can enhance anti-tumor immunity and improve survival of patients.

Cancer remains a significant public health issue worldwide, standing as a primary contributor to global mortality, accounting for approximately 10 million fatalities in 2020 [...].

Acquisition of genomic mutations enables cancer cells to gain fitness advantages under selective pressure and, ultimately, leads to oncogenic transformation. Interestingly, driver mutations, even within the same gene, can yield distinct phenotypes and clinical outcomes, necessitating a mutation-focused approach. Conversely, cellular functions are governed by molecular machines and signalling networks that are mostly controlled by protein-protein interactions (PPIs). The functional impact of individual genomic alterations could be transmitted through regulated nodes and hubs of PPIs. Oncogenic mutations may lead to modified residues of proteins, enabling interactions with other proteins that the wild-type protein does not typically interact with, or preventing interactions with proteins that the wild-type protein usually interacts with. This can result in the rewiring of molecular signalling cascades and the acquisition of an oncogenic phenotype. Here, we review the altered PPIs driven by oncogenic mutations, discuss technologies for monitoring PPIs and provide a functional analysis of mutation-directed PPIs. These driver mutation-enabled PPIs and mutation-perturbed PPIs present a new paradigm for the development of tumour-specific therapeutics. The intersection of cancer variants and altered PPI interfaces represents a new frontier for understanding oncogenic rewiring and developing tumour-selective therapeutic strategies.

Cancer immunotherapy has revolutionized cancer treatment, but therapeutic ineffectiveness-driven by the tumor microenvironment and immune evasion mechanisms-continues to limit its clinical efficacy. This challenge underscores the need to explore innovative approaches, such as multimodal immunotherapy. Phytochemicals, bioactive compounds derived from plants, have emerged as promising candidates for overcoming these barriers due to their immunomodulatory and antitumor properties. This review explores the synergistic potential of phytochemicals in enhancing immunotherapy by modulating immune responses, reprogramming the tumor microenvironment, and reducing immunosuppressive factors. Integrating phytochemicals with conventional immunotherapy strategies represents a novel approach to mitigating resistance and enhancing therapeutic outcomes. For instance, nab-paclitaxel has shown the potential in overcoming resistance to immune checkpoint inhibitors, while QS-21 synergistically enhances the efficacy of tumor vaccines. Furthermore, we highlight recent advancements in leveraging nanotechnology to engineer phytochemicals for improved bioavailability and targeted delivery. These innovations hold great promise for optimizing the clinical application of phytochemicals. However, further large-scale clinical studies are crucial to fully integrate these compounds into immunotherapeutic regimens effectively.

Immunotherapy with checkpoint inhibitors has become the cornerstone of systemic treatment for non-oncogene addicted non-small-cell lung cancer. Despite its pivotal role, a significant proportion of patients-approximately 70-85%-either exhibit primary resistance to PD-1 blockade or develop acquired resistance following an initial benefit, even in combination with chemotherapy and/or anti-CTLA-4 agents. The phenomenon of primary and acquired resistance to immunotherapy represents a critical clinical challenge, largely based on our incomplete understanding of the mechanisms of action of immunotherapy, and the resulting lack of accurate predictive biomarkers. Here, we review the definitions and explore the proposed mechanisms of primary and acquired resistance, including those related to the tumor microenvironment, systemic factors, and intrinsic tumor characteristics. We also discuss translational data on adaptive changes within tumor cells and the immune infiltrate following exposure to checkpoint inhibitors. Lastly, we offer a comprehensive overview of current and emerging therapeutic strategies designed to prevent primary resistance and counteract acquired resistance.

Cancer immunotherapy is increasingly used in clinical practice, but its success rate is reduced by tumor escape from the immune system. This may be due to the genetic instability of tumor cells, which allows them to adapt to the immune response and leads to intratumoral immune heterogeneity. The study investigated spatial immune heterogeneity in the tumor microenvironment and its possible drivers in a mouse model of tumors induced by human papillomaviruses (HPV) following immunotherapy. Gene expression was determined by RNA sequencing and mutations by whole exome sequencing. A comparison of different tumor areas revealed heterogeneity in immune cell infiltration, gene expression, and mutation composition. While the mean numbers of mutations with every impact on gene expression or protein function were comparable in treated and control tumors, mutations with high or moderate impact were increased after immunotherapy. The genes mutated in treated tumors were significantly enriched in genes associated with ECM metabolism, degradation, and interactions, HPV infection and carcinogenesis, and immune processes such as antigen processing and presentation, Toll-like receptor signaling, and cytokine production. Gene expression analysis of DNA damage and repair factors revealed that immunotherapy upregulated Apobec1 and Apobec3 genes and downregulated genes related to homologous recombination and translesion synthesis. In conclusion, this study describes the intratumoral immune heterogeneity, that could lead to tumor immune escape, and suggests the potential mechanisms involved.

While immune checkpoint inhibition (CPI) has reshaped cancer treatment, the majority of patients with cancer do not benefit from this approach, which can also cause immune-related adverse events. Induction of IFN-γ responses is thought be necessary for antitumor immunity, but growing evidence also implicates IFN-γ as a tumor-intrinsic mediator of CPI resistance. CPI-induced IFN-γ mediates activation-induced cell death in T cells as an immune-intrinsic mechanism of resistance. In this study, we found that transient block of IFN-γ signaling through administration of the JAK1 inhibitor ABT-317 enhanced antitumor T cell responses with CPI in preclinical models. Importantly, sequential but not concomitant ABT-317 treatment led to significantly reduced toxicity and improved tumor efficacy. Sequential treatment reduced activation-induced T cell death and enhanced expansion of tumor-reactive T cell subsets with increased effector function in vivo and ex vivo. Only CPI in combination with ABT-317 also enhanced memory responses by protecting mice from tumor rechallenge. These results demonstrate that JAK inhibition within a discrete time window following CPI addresses an immune-intrinsic mechanism of therapeutic resistance.

Brain metastases in esophageal adenocarcinoma (EAC) patients are associated with poor prognosis and remain understudied. We performed multi-omics analysis with whole-genome sequencing and single-cell spatial transcriptomics on the brain metastases and matched primary tumors. Our analysis identified ERBB2 as a recurrent oncogene in EAC brain metastases, with 9 out of 10 cases harboring amplifications. Single-cell whole-genome and multi-region sequencing revealed that ERBB2 alterations, occur early during disease progression and are associated with monoclonal seeding. Although the median survival in our cohort was 13 months, one patient on HER2 antibody-drug conjugate therapy remains a long-term survivor beyond 34 months. Interestingly, the sole patient without an ERBB2 alteration had JAK2 deletion, high T cell infiltration in the brain lesion, and survived 35 months after immune checkpoint therapy. Our findings have significant clinical implications for the treatment and management of EAC brain metastases.

Over the past several years, the therapeutic landscape for patients with advanced, unresectable, or metastatic hepatocellular carcinoma has been transformed by the incorporation of checkpoint inhibitor immunotherapy into the treatment paradigm. Frontline systemic treatment options have expanded beyond anti-angiogenic tyrosine kinase inhibitors, such as sorafenib, to a combination of immunotherapy approaches, including atezolizumab plus bevacizumab and durvalumab plus tremelimumab, both of which have demonstrated superior response and survival to sorafenib. Additionally, combination treatments with checkpoint inhibitors and tyrosine kinase inhibitors have been investigated with variable success. In this review, we discuss these advances in systemic treatment with immunotherapy, with a focus on understanding both the underlying biology and mechanism of these strategies and their efficacy outcomes in clinical trials. We also review challenges in identifying predictive biomarkers of treatments and discuss future directions with novel immunotherapy targets.

Immune checkpoint inhibitors (ICIs) have demonstrated significantly improved clinical efficacy in a minority of patients with advanced melanoma, whereas non-responders potentially suffer from severe side effects and delays in other treatment options. Predicting the response to anti-PD1 treatment in melanoma remains a challenge because the current FDA-approved gold standard, the nonsynonymous tumor mutation burden (nsTMB), offers limited accuracy.

In this study, we developed a multi-omics-based machine learning model that integrates genomic and transcriptomic biomarkers to predict the response to anti-PD1 treatment in patients with advanced melanoma. We employed least absolute shrinkage and selection operator (LASSO) regression with 49 biomarkers extracted from tumor-normal whole-exome and RNA sequencing as input features. The performance of the multi-omics AI model was thoroughly compared to that of nsTMB alone and to models that use only genomic or transcriptomic biomarkers.

We used publicly available DNA and RNA-seq datasets of melanoma patients for the training and validation of our model, forming a meta-cohort of 449 patients for which the outcome was recorded as a RECIST score. The model substantially improved the prediction of anti-PD1 outcomes compared to nsTMB alone, with an ROC AUC of 0.7 in the training set and an ROC AUC of 0.64 in the test set. Using SHAP values, we demonstrated the explainability of the model's predictions on a per-sample basis.

We demonstrated that models using only RNA-seq or multi-omics biomarkers outperformed nsTMB in predicting the response of melanoma patients to ICI. Furthermore, our machine learning approach improves clinical usability by providing explanations of its predictions on a per-patient basis. Our findings underscore the utility of multi-omics data for selecting patients for treatment with anti-PD1 drugs. However, to train clinical-grade AI models for routine applications, prospective studies collecting larger melanoma cohorts with consistent application of exome and RNA sequencing are required.

Resistance to anti-PD-1 therapy in melanoma remains a major obstacle in achieving effective and durable treatment outcomes, highlighting the need to understand and address the underlying mechanisms. The first key factor is innate anti-PD-1 resistance signature (IPRES), an expression of a group of genes associated with tumor plasticity and immune evasion. IPRES promotes epithelial-to-mesenchymal transition (EMT), increasing melanoma cells' invasiveness and survival. Overexpressed AXL, TWIST2, and WNT5a induce phenotypic changes. The upregulation of pro-inflammatory cytokines frequently coincides with EMT-related changes, further promoting a resistant and aggressive tumor phenotype. Inflamed tumor microenvironment may also drive the expression of resistance. The complexity of immune resistance development suggests that combination therapies are necessary to overcome it. Furthermore, targeting epigenetic regulation and exploring novel approaches such as miR-146a modulation may provide new strategies to counter resistance in melanoma.

Our study reveals UBA1 as a predictive biomarker for clinical outcomes in ICB cohorts, mediating cancer immune evasion and ICB resistance. We further highlight JAK1 stabilization as a key mechanism of UBA1 inhibition and nominate the UBA1-STUB1 axis as an immuno-oncology therapeutic target to improve the efficacy of ICB.

For most colorectal cancer (CRC) patients, expanding the benefits of immunotherapy, particularly through blocking programmed cell death-1 (PD-1) and its ligand (PD-L1), is crucial, especially in cases with limited response to neoadjuvant therapy. This study investigates the role of Myoferlin (MYOF) as a novel target in CRC immunotherapy.

Human CRC cell lines (RKO, HCT116), normal intestinal epithelial cells (HIEC-6), and the murine CRC cell line MC38 were used to study the effects of apatinib and MYOF in CRC cells. RNA sequencing, the CPTAC and TCGA databases, and other molecular and cellular methods were applied to disclose the mechanisms involved. A series of mouse models were established to assess the effects of apatinib and MYOF knockdown on tumor progression, immune cell infiltration, and immune checkpoint protein response.

We found that MYOF is overexpressed in CRC and linked to immune cell infiltration and checkpoint expression. Suppression of MYOF expression significantly inhibited CRC cell proliferation and migration, as well as reduced PD-L1 protein levels. Integrative analysis showed that apatinib modulates MYOF expression via VEGFR2, resulting in decreased PD-L1 expression, increased CD8+ T cell infiltration, and reduced pro-tumor M2 macrophages. Animal experiments further revealed that apatinib treatment or MYOF knockdown enhanced the efficacy of immune checkpoint blockade (ICB) in CRC.

These findings highlight novel antitumor mechanisms of MYOF and suggest that combining apatinib with ICB therapy may improve CRC treatment outcomes, offering a promising strategy to enhance immune responses.

Over the years, extensive research has been dedicated to performing in-depth analysis of cancer to uncover the intricate details of its nature - including the types of cancer, causative agents, stimulators of disease progression, factors contributing to poor prognosis, and efficient therapies to restrict the metastatic aggressiveness. This chapter highlights the mechanisms through which different arms of the host immune system - namely cytokines, lymphocytes, antigen-presenting cells (APCs) -can be mobilized to eradicate cancer. Most malignant tumors are either poorly immunogenic, or are harbored in a highly immuno-suppressive microenvironment. This is why reinforcing the host's anti-tumor defenses, through infusion of pro-inflammatory cytokines, tumor antigen-loaded APCs, and anti-tumor cytotoxic cells has emerged as a viable treatment option against cancer. The chapter also highlights the ongoing preclinical and clinical studies in different malignancies and the outcome of various therapies. Although these methods are not foolproof, and antigen escape variants can still evade or develop resistance to customized therapies, they achieve disease stabilization in several cases when conventional treatments fail. In many instances, combination therapies involving cytokines, T cells, and vaccinations prove more effective than monotherapies. The limitations of the current therapies are also discussed, along with ongoing modifications aimed at improving efficacy.

Immune checkpoint inhibitors against PD-1/PD-L1 are highly effective in immunologically hot tumours such as triple-negative breast cancer, wherein constitutive DNA damage promotes inflammation, while inducing PD-L1 expression to avoid attack by cytotoxic T cells. However, whether and how PD-L1 regulates the DNA damage response and inflammation remains unclear. Here, we show that nuclear PD-L1 activates the ATR-Chk1 pathway and induces proinflammatory chemocytokines upon genotoxic stress. PD-L1 interacts with ATR and is essential for Chk1 activation and chromatin binding. cGAS-STING and NF-κB activation in the late phase of the DNA damage response is inhibited by PD-L1 deletion or by inhibitors of ATR and Chk1. Consequently, the induction of proinflammatory chemocytokines at this stage is inhibited by deletion of PD-L1, but restored by the ATR activator Garcinone C. Inhibition of nuclear localisation by PD-L1 mutations or the HDAC2 inhibitor Santacruzamate A inhibits chemocytokine induction. Conversely, the p300 inhibitor C646, which accelerates PD-L1 nuclear localisation, promotes chemocytokine induction. These findings suggest that nuclear PD-L1 strengthens the properties of hot tumours and contributes to shaping the tumour microenvironment.

IFNs play a critical role in cancer biology, including impacting tumor cell behavior and instructing the tumor microenvironment (TME). IFNs recently have been shown to reprogram tumor metabolism through distinct mechanisms. Furthermore, IFNs shape the TME by modulating immune cell infiltration and function, contributing to the intricate interaction between the tumor and stromal cells. This review summarizes the effects of IFNs on metabolic reprogramming and their impacts on the function of immune cells within the TME, with a particular focus on the dual roles of IFNs in mediating both anti-tumor and pro-tumor immune responses. Understanding the significance of IFNs-mediated processes aids to advise future therapeutic strategies in cancer treatment.

Src homology-2-containing protein tyrosine phosphatase 2 (SHP2) plays a dual role in cancer initiation and progression. Identifying signals that modulate the function of SHP2 can improve current therapeutic approaches for IFN-α/β in HCC. We showed that cAMP-dependent PKA suppresses IFN-α/β-induced JAK/STAT signaling by increasing the phosphatase activity of SHP2, promoting the dissociation of SHP2 from the receptor for activated C-kinase 1 (RACK1) and binding to STAT1. Additionally, cAMP-degrading phosphodiesterase 4D (PDE4D) physically interacts with RACK1 to regulate PKA-mediated SHP2 activity and STAT1 phosphorylation. IFN-α activates PKA by inducing the expression of cyclooxygenase 2 (COX2) and the production of prostaglandin E2 (PGE2), which in turn stimulates the binding of SHP2 to IFNAR2 via RACK1. A COX inhibitor aspirin potently increases the antitumor effects of IFN-α in the suppression of HCC cell proliferation in vivo. Higher expression of COX2 and phosphorylated STAT3 is associated with poor development and prognosis in HCC patients by analyzing human HCC clinical samples. These observations suggest that a fundamental PKA/SHP2-dependent negative feedback loop acts on IFN signaling, and inhibition of this signaling by the selective COX2 inhibitors may enhance the clinical efficacy of type I IFNs in treating HCC.

Malignant melanoma is characterized by high immunogenicity, genetic heterogeneity, and diverse pathological manifestations, affecting both skin and mucosa over the body. Pembrolizumab and nivolumab, both anti-PD-1 monoclonal antibodies, were approved by the US FDA for unresectable or metastatic melanoma in 2011 and 2014, respectively, with enduring and transformative outcomes. Despite marked clinical achievements, only a subset of patients manifested a complete response. Approximately 55% of melanoma patients exhibited primary resistance to PD-1 antibodies, with nearly 25% developing secondary resistance within 2 years of treatment. Thus, there is a critical need to comprehensively elucidate the mechanisms underlying the efficacy and resistance to PD-1 blockade. This review discusses the fundamental mechanisms of PD-1 blockade, encompassing insights from T cells and B cells, and presents resistance to anti-PD-1 with a particular focus on tumoral-intrinsic mechanisms in melanoma.