Shalini T, Sudhandiran G. Provoking myofibroblast death: Strategies to resolve fibrosis and remodel tumor microenvironment. World J Clin Oncol 2025; 16(12): 111086 [DOI: 10.5306/wjco.v16.i12.111086]
Corresponding Author of This Article
Ganapasam Sudhandiran, PhD, Professor, Cell Biology Laboratory, Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, Tamil Nādu, India. sudhandiran@yahoo.com
Research Domain of This Article
Cell Biology
Article-Type of This Article
Minireviews
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Author contributions: Shalini T and Sudhandiran G contributed equally to the conception, literature collection, manuscript drafting, and critical revisions; and all authors approved the final manuscript.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ganapasam Sudhandiran, PhD, Professor, Cell Biology Laboratory, Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, Tamil Nādu, India. sudhandiran@yahoo.com
Received: June 23, 2025 Revised: July 28, 2025 Accepted: November 13, 2025 Published online: December 24, 2025 Processing time: 183 Days and 21.2 Hours
Abstract
Fibrosis is marked by the excessive accumulation of extracellular matrix (ECM) components, leading to tissue scarring and progressive loss of organ function. Myofibroblasts, which emerge during tissue repair, are specialized contractile cells exhibiting features of both fibroblasts and smooth muscle cells. Their expression of α-smooth muscle actin facilitates contractile activity, while their persistent activation and overproduction of ECM components contribute significantly to pathological wound contraction and fibrotic progression. Beyond ECM production, myofibroblasts play a significant role in the tumor microenvironment (TME) of various solid tumors. The TME is a complex network of immune cells, blood vessels, ECM components, and stromal cells like fibroblasts and myofibroblasts that surrounds and interacts with cancer cells, thereby influencing tumor growth, progression, and therapy responsiveness. Through these interactions, myofibroblasts modulate inflammation, angiogenesis, and tissue remodeling. Maintaining myofibroblast homeostasis is therefore crucial, as its disruption can drive the onset of chronic fibrotic conditions and malignancies. This review explores preclinical and clinical developments in targeting myofibroblasts in fibrotic and TME across various disease models, including hypertrophic scar, idiopathic pulmonary fibrosis, oral submucous fibrosis, cardiac fibrosis, and the desmoplastic stroma of pancreatic and breast cancers.
Core Tip: Myofibroblasts are contractile cells that play a central role in both fibrosis and tumor progression due to their involvement in excessive extracellular matrix deposition and tissue stiffening. This article highlights emerging strategies to selectively inactivate or induce myofibroblast death, aiming to resolve fibrosis and remodel the tumor microenvironment. By exploring diverse disease models of fibrosis and cancer, this review underscores the therapeutic potential of targeting myofibroblasts to halt chronic tissue damage and improve cancer treatment outcomes.
Citation: Shalini T, Sudhandiran G. Provoking myofibroblast death: Strategies to resolve fibrosis and remodel tumor microenvironment. World J Clin Oncol 2025; 16(12): 111086
Fibroblasts are key stromal cells responsible for synthesizing fibrous proteins such as collagen and fibronectin, thereby maintaining tissue structure and mechanical integrity. Upon tissue injury, fibroblasts activate and differentiate into myofibroblasts, acquiring contractile and extracellular matrix (ECM) remodeling functions essential for wound repair[1]. Under normal conditions, these activated cells either undergo apoptosis or revert to a quiescent state following tissue recovery[2]. However, persistent injury or chronic inflammation results in sustained myofibroblast activation, leading to excessive ECM deposition, tissue stiffening, and progressive organ dysfunction (Figure 1).
Figure 1 Myofibroblasts/cancer associated fibroblasts in fibrosis and tumor microenvironment.
Left panel: Upon external or internal stressors, epithelial cell injury triggers epithelial-to-mesenchymal transition, mediated by inflammatory cytokines (e.g., transforming growth factor, tumor necrosis factor, platelet derived growth factor) released by immune cells such as macrophages. This leads to fibroblast activation through fibroblast-to-myofibroblast transition, marked by the expression of α-smooth muscle actin, fibroblast activator protein, and collagen I/III, which contribute to excessive extracellular matrix deposition. Persistent myofibroblast activation leads to fibrosis, in contrast inducing myofibroblast death could resolve fibrosis. Right panel: Within the tumor microenvironment, cancer-associated myofibroblasts promote tumor progression by enhancing angiogenesis, supporting immune evasion, initiating metastasis, and remodeling the excessive extracellular matrix. The cellular interactions involve multiple components, including T cells, macrophages, dendritic cells, and cancer cells. Myofibroblast depletion or reprogramming may thus serve as a therapeutic strategy to mitigate fibrosis and recondition the tumor microenvironment. TGF-β1: Transforming growth factor; TNF-α: Tumor necrosis factor α; PDGF: Platelet derived growth factor; EMT: Epithelial-to-mesenchymal transition; FMT: Fibroblast-to-myofibroblast transition; α-SMA: α-smooth muscle actin; FAP: Fibroblast activator protein; TME: Tumor microenvironment; ECM: Excessive extracellular matrix; CAF: Cancer-associated myofibroblast.
In addition to their roles in fibrosis, myofibroblast-like cells contribute to the tumor microenvironment (TME) in solid malignancies. The TME is composed of both cancerous and non-cancerous cells, including fibroblasts, immune cells, and endothelial cells embedded within the ECM[3]. In cancers such as breast, pancreatic, and colorectal, a dense, fibroblast-rich stroma constitutes a major portion of tumour mass[4]. These cancer-associated fibroblasts (CAFs) actively promote tumour growth, immune evasion, invasion, and therapeutic resistance[4,5]. Although CAFs arise from diverse origins, many express myofibroblast markers like α-smooth muscle actin (α-SMA) and share features with fibrotic myofibroblasts, including persistent activation via transforming growth factor-β (TGF-β) signaling, mechanotransduction (conversion of mechanical cues into intracellular signals), and oxidative stress[6,7].
Given their dual roles in fibrosis and tumor progression, long-lived myofibroblasts have emerged as therapeutic targets. While traditional approaches focused on limiting fibroblast activation or ECM accumulation, recent strategies aim to eliminate or functionally reprogram myofibroblasts. This includes disrupting survival pathways, exploiting their unique biomechanical properties, or modulating their immune and metabolic adaptations (Figure 2). Such approaches offer potential not only to halt fibrosis and remodel tumor stroma but also to enhance treatment efficacy across fibrotic and oncologic settings. This review highlights emerging therapeutic interventions targeting myofibroblast contractility, mitochondrial priming, immune evasion, redox balance, and stromal remodeling through chimeric antigen receptor T (CAR-T) and senolytic therapies, with relevance to both fibrotic diseases and cancer (Table 1).
During tissue development and repair, fibroblasts originate from mesenchymal cells and display phenotypic plasticity, ranging from ECM-synthesizing non-contractile fibroblasts to highly contractile myofibroblasts involved in wound contraction and matrix remodeling[1,8]. The transition to myofibroblasts is primarily driven by growth factors such as epidermal growth factor, TGF-β, fibroblast growth factor, and insulin-like growth factor II[9].
While traditionally attributed to resident mesenchymal cells, activated fibroblasts and myofibroblasts also arise through epithelial-to-mesenchymal transition (EMT) and fibroblast-to-myofibroblast transition (FMT)[9]. EMT enables epithelial cells to lose polarity and adhesion, acquiring mesenchymal characteristics that include motility, invasiveness, and enhanced ECM production[9,10]. This transition is mediated by signaling molecules such as TGF-β, Wnt, and Notch, which induce transcription factors like Snail, Slug, and Twist. Accumulating evidence from our own laboratory observations and other investigators suggest that, EMT contributes to the expansion of fibroblast-like cell populations that drive excessive ECM deposition and tissue remodeling, particularly in organs such as the lungs, kidneys, and liver[11,12]. FMT, on the other hand, marks the final step of differentiation, wherein fibroblasts express α-SMA and increase collagen and fibronectin synthesis[13]. EMT and FMT together form a pathological feedback loop. EMT expands the fibroblast pool, and FMT amplifies ECM output resulting in progressive fibrosis[14].
A transitional phenotype termed “proto-myofibroblast” describes cells that initiate ECM production and cytoskeletal remodeling but lack full α-SMA expression and contractility[14-16]. In tumours, fibroblasts within the TME frequently exhibit myofibroblast-like features. CAFs, particularly the α-SMA-high subtype (myCAFs), mirror fibrotic myofibroblasts in contractile function and TGF-β responsiveness[17,18]. Other CAFs, like inflammatory CAFs, are characterized by interleukin (IL)-6 production and immune-modulatory roles. These subsets differentially localize within tumors, with myCAFs accumulating near tumor cells and inflammatory CAFs influencing immune cells at the periphery[17]. Given their molecular and functional similarities, targeting activated fibroblasts in both fibrosis and cancer can follow shared principles. Many CAFs are marked by TGF-β-dependent activation and myofibroblast markers such as α-SMA and fibroblast activation protein (FAP) α, providing common targets for therapeutic strategies[19].
Understanding the origin and plasticity of myofibroblasts and CAFs is critical for developing effective antifibrotic and anticancer therapies. Therapeutic interventions aimed at disrupting EMT/FMT transitions or depleting myofibroblast-like CAF subsets may halt disease progression, reduce ECM burden, and improve tissue function and drug delivery in both fibrotic and tumour contexts.
TARGETING MYOFIBROBLAST CONTRACTILITY, MATRIX STIFFNESS, AND MECHANOTRANSDUCTION
Myofibroblasts remodel tissues through slow, energy-efficient contractions mediated by actin stress fibers and ECM remodeling (reorganization and modification of extracellular matrix structure)[20]. These cells anchor to the matrix through fibronexus structures that connect intracellular α-SMA filaments to extracellular collagen fibrils[21]. During contraction, force is transmitted to the ECM, inducing local fiber alignment and tissue shortening[20]. Over time, the remodelled matrix becomes stabilized and stiffened by continued ECM deposition, creating a positive feedback loop that maintains pathological tissue tension[22,23].
Mechanotransduction, the process by which cells translate ECM stiffness into intracellular signals, plays a pivotal role in maintaining myofibroblast activation[24]. Central to this process is the Hippo-Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) signaling pathway. Under conditions of high mechanical tension, YAP and TAZ translocate to the nucleus, where they interact with TEA domain transcription factors to drive the expression of pro-fibrotic, pro-survival, and migratory genes[25].
In healthy tissue, upstream kinases mammalian STE20-like kinases 1/2 and large tumor suppressor 1/2 phosphorylate and inactivate YAP/TAZ, retaining them in the cytoplasm and promoting degradation. In fibrosis and cancer, however, this regulation is lost, leading to sustained YAP/TAZ nuclear localization and persistent myofibroblast activation[26,27]. YAP/TAZ dysregulation has been implicated in fibrotic remodelling of the heart (cardiac fibrosis), liver (e.g., non-alcoholic steatohepatitis), kidney, and lung (e.g., idiopathic pulmonary fibrosis)[28,29], as well as in tumour progression in pancreatic, breast, and liver cancers through effects on EMT, immune evasion, and CAF activation[30].
YAP/TAZ inhibitors are now being explored as therapeutic agents[31]. Verteporfin, a YAP-TEA domain interaction inhibitor, demonstrates antifibrotic effects in renal fibroblasts[32] and antitumor activity in breast[33] and pancreatic cancer models[34]. However, its clinical application is limited by non-specific cytotoxicity[35], light-induced photosensitivity[36], and poor pharmacokinetics[37]. CA3, a more selective YAP inhibitor, has shown efficacy in triple-negative breast cancer[38]. Targeting upstream regulators like dasatinib (a Src family kinase inhibitor) may offer indirect inhibition of YAP/TAZ and is under investigation in prostate cancer[39]. Additionally, statins suppress YAP/TAZ activation via inhibition of the mevalonate pathway and offer repurposing potential in fibrotic and oncologic settings[40]. Targeting mechanotransduction also includes strategies to disrupt the biomechanical interface at the plasma membrane. Di-rhamnolipid, a biosurfactant produced by Pseudomonas aeruginosa, disrupts lipid bilayers and induces membrane leakage in contractile myofibroblasts. In hypertrophic scar (HS) models, Di-rhamnolipid treatment resulted in calcium, calcein, and lactate dehydrogenase release from myofibroblasts, suggesting membrane rupture and cell death[41,42].
Mechanosensitive myofibroblasts within the tumour microenvironment, particularly α-SMA+/FAPα+ CAFs, are also targets for combined stromal and cytotoxic therapies. A dual-stage “TC-Therapy” approach using SB525334 (a TGF-β receptor I inhibitor) and docetaxel-loaded micelles has shown promise in pancreatic cancer models. SB525334 reduces myCAF populations and ECM stiffness, improving drug delivery, while docetaxel-loaded micelles promotes mitotic arrest and apoptosis in both tumor cells and fibroblasts[43]. Targeting myofibroblast mechanotransduction and contractility disrupts the feedback loop of tissue stiffening and activation that drives fibrosis and tumor progression. Pharmacological inhibition of YAP/TAZ signalling and mechanical remodeling therapies, including statins, verteporfin, and Src kinase inhibitors, offer therapeutic avenues to reduce fibrotic burden, improve drug penetration, and enhance treatment efficacy in solid tumors and fibrotic organs.
TARGETING MITOCHONDRIAL PRIMING AND B-CELL LYMPHOMA 2-MEDIATED APOPTOSIS
Mitochondrial priming refers to how close a cell is to undergoing apoptosis via the intrinsic pathway, largely determined by the balance between pro-apoptotic and anti-apoptotic members of the B-cell lymphoma (BCL) 2 protein family[44]. These proteins regulate mitochondrial outer membrane permeabilization, a critical step that leads to cytochrome c release and activation of caspases. B-cell lymphoma 2 homology 3 (BH3)-only activators such as BCL-2 interacting mediator of cell death (BIM) trigger this process by activating effectors such as BCL-2-associated X protein and BCL-2 antagonist/killer. Anti-apoptotic proteins like BCL-2, BCL-extra-large (BCL-XL), myeloid cell leukemia 1 (MCL-1) prevent apoptosis by sequestering these activators or effectors[45-47].
In fibrosis, ECM stiffness sustains myofibroblast survival despite elevated levels of pro-apoptotic proteins like BIM. This is due to a parallel upregulation of anti-apoptotic proteins, particularly BCL-2 and MCL-1[48,49]. This primed-but-protected state creates a therapeutic window for BH3 mimetics, a small molecule that mimic pro-apoptotic BH3 domains and selectively inhibit survival proteins to trigger apoptosis[47]. Navitoclax (ABT-263), a BH3 mimetic targeting BCL-2, BCL-XL, and MCL-1, has been shown to induce apoptosis in activated myofibroblasts. In fibrotic tissues, stiffness-primed myofibroblasts displayed higher mitochondrial priming and were more sensitive to navitoclax-induced apoptosis[50]. BH3 profiling has proven valuable in identifying such susceptibility in both fibrotic and tumor contexts.
In breast CAFs, MCL-1 is a key survival factor. The BH3 mimetic S63845 selectively inhibits MCL-1, and although it does not robustly induce apoptosis, it causes loss of α-SMA expression and contractile features, along with mitochondrial fragmentation and YAP cytoplasmic retention[51]. Mechanosensitive regulation of BCL-XL also plays a role in apoptotic resistance. In dermal myofibroblasts exposed to matrix stiffness, BCL-XL sequesters BIM. Inhibition of integrin-focal adhesion kinase (FAK) signaling decreases BCL-XL expression and restores apoptotic sensitivity, offering a mechanistically targeted antifibrotic strategy[52].
FAK is a cytoplasmic tyrosine kinase localized at focal adhesions that integrates mechanical signals to promote fibroblast survival, motility, and ECM remodeling. In solid tumors, FAK activation drives CAF differentiation and stromal barrier formation, impairing drug penetration. IN10018, a small molecule FAK inhibitor, reduces CAF activity, decreases stromal density, and improves antibody-drug conjugate efficacy in preclinical tumor models[53]. In pulmonary fibrosis, elevated FAK levels have been noted in fibroblast foci. Pharmacological or small interfering RNA-mediated FAK inhibition significantly attenuated bleomycin-induced lung fibrosis and suppressed profibrotic gene expression[54]. Downstream of FAK, Rho-associated protein kinases (ROCK) 1/2 mediate actin cytoskeletal remodeling. Through regulation of stress fibers, focal adhesions, and motility, ROCK influences myofibroblast phenotype and survival[55-57]. Inhibition of ROCK by Y-27632 reduced macrophage and neutrophil infiltration and suppressed fibroblast migration and proliferation in a bleomycin lung injury model[58].
Fasudil, a clinically approved ROCK inhibitor, blocks FMT, induces apoptosis, and reduces fibrosis in vivo by triggering cytoskeletal depolymerization and mitochondrial pathway activation[59]. This sequence of events in actin disassembly followed by apoptosis reinforces the mechanosensitive dependency of myofibroblasts. Myofibroblasts rely on anti-apoptotic defense for survival in stiff ECM environments. BH3 mimetics (navitoclax, S63845), along with upstream regulators such as FAK and ROCK inhibitors (IN10018, fasudil), can selectively overcome this resistance. These agents restore mitochondrial priming, promote apoptosis, and offer a promising strategy for resolving fibrosis and dismantling stromal barriers in cancer.
TARGETING OXIDATIVE STRESS
Reactive oxygen species (ROS) are central mediators in fibrosis and tumour progression. While low-to-moderate ROS levels support tissue repair, excessive or sustained ROS production drives chronic inflammation, ECM deposition, and pathological remodelling[60-63]. Major sources of ROS include mitochondrial respiratory complexes, nicotinamide adenine dinucleotide phosphate oxidases, cytochrome P450 enzymes, and non-enzymatic triggers such as radiation and environmental toxins[64].
In fibrotic tissues, persistent ROS generation sustains TGF-β signaling, activates latent fibrogenic cytokines, and supports myofibroblast survival. Interestingly, myofibroblasts adapt to oxidative stress by upregulating antioxidant systems, particularly through the nuclear factor erythroid 2-related factor 2-Kelch like ECH associated protein 1 pathway[65,66]. In CAFs, this adaptation paradoxically enables their persistence within ROS-rich environments, contributing to tumor immune evasion and therapeutic resistance[67]. These insights have led to therapeutic approaches that exploit redox imbalance. Rather than neutralizing ROS, pro-oxidant strategies aim to overwhelm antioxidant capacity and induce selective cell death in apoptosis-resistant myofibroblasts[68].
In HS models, the alkaloid lycorine significantly reduced α-SMA expression and collagen deposition in myofibroblasts. It elevated intracellular ROS levels, which activated mitochondria-mediated intrinsic apoptosis. These effects were validated in a rabbit ear model of HS[69]. Elesclomol, initially developed for metastatic melanoma, elevates intracellular ROS and transports copper ions into cells, disrupting mitochondrial function and causing DNA damage[70]. Recent evidence suggests that elesclomol may trigger cuproptosis, a unique copper-dependent cell death pathway offering a novel route for targeting metabolically active myofibroblasts[70]. In HS fibroblasts, elesclomol induced oxidative stress and effectively promoted apoptosis[71]. While promising, pro-oxidant therapies require precise control to minimize off-target toxicity. High systemic ROS levels may damage healthy tissues or accelerate aging-related pathologies if antioxidant defence are broadly suppressed. Targeting oxidative stress by elevating ROS or suppressing antioxidant defences presents a novel strategy for eliminating apoptosis-resistant myofibroblasts. Compounds like lycorine and elesclomol show potential in fibrotic and tumor settings by promoting oxidative stress-induced apoptosis. Future therapeutic success will depend on achieving selective cytotoxicity while preserving normal tissue function.
TARGETING IMMUNE PRIVILEGE MECHANISMS
Immune privilege is a physiological mechanism that allows certain tissues to tolerate foreign antigens without triggering an inflammatory immune response. This concept applies to anatomical sites such as the cornea, eye, testes, brain, placenta, and joints, where immune-mediated damage could cause irreversible functional loss[72,73]. Interestingly, a similar phenomenon may contribute to the prolonged survival of myofibroblasts following tissue repair. In fibrotic and tumour microenvironments, myofibroblasts may adopt immune privilege-like features that prevent their clearance by immune cells. This allows them to persist and sustain fibrosis or stromal remodeling long after the original injury or tumor has resolved[74].
In cancer, immune evasion is frequently mediated through the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) checkpoint pathway. PD-L1 expressed on tumour or stromal cells, binds PD-1 on activated T cells, reducing their cytotoxic activity. This interaction is amplified by TGF-β1-driven small mothers against decapentaplegic homolog 3 signalling within the tumour microenvironment[75]. Elevated PD-L1 expression has been observed in oral squamous cell carcinoma (OSCC) cases associated with oral submucous fibrosis. PD-L1 overexpression in oral submucous fibrosis-linked OSCC correlates with advanced tumour stage, lymph node metastasis, and poor prognosis[76].
Additionally, tryptophan 2,3-dioxygenase (TDO2)-positive myofibroblasts have been identified in tumor-adjacent tissues in OSCC and oral leukoplakia. These cells promote immune evasion by converting CD4+ T cells into regulatory T cells and inducing CD8+ T cell exhaustion via checkpoint molecules such as PD-1 and T cell immunoglobulin and mucin-domain containing protein 3[77]. Inhibiting TDO2 using LM10 has demonstrated success in murine OSCC models. LM10 treatment reduced immunosuppressive myofibroblasts and enhanced T cell-mediated anti-tumor responses, halting disease progression[77]. Despite these encouraging findings, systemic inhibition of TDO2 may have off-target effects. Tryptophan metabolism is important for gut and neuronal function, and long-term inhibition may disrupt physiological homeostasis[78]. Therefore, targeting immune-privileged myofibroblasts must be approached with tissue specificity and safety in mind.
Myofibroblasts with immune privilege-like properties contribute to persistent fibrosis and immune evasion in tumours. Strategies targeting immune checkpoints and metabolic enzymes, such as PD-L1 and TDO2, offer therapeutic potential in fibrotic diseases and cancer. However, achieving immune modulation without systemic toxicity remains a critical challenge for clinical translation.
CAR-T THERAPIES
Chimeric antigen receptor (CAR) T-cell therapy is a promising immunotherapeutic approach in which a patient’s T cells are genetically engineered to recognize and kill specific target cells. While CAR-T therapies have demonstrated significant success in haematological malignancies, their application in solid tumours remains limited by challenges such as antigen heterogeneity, poor infiltration, and a suppressive tumour microenvironment[79].
One major limitation in solid tumours is the lack of specific tumor-specific antigens. Most tumour-associated antigens are heterogeneously expressed and may also be found at low levels in normal tissues. This increases the risk of on-target, off-tumour toxicity, as seen with HER2-targeted CAR-T therapies that caused severe side effects by attacking normal epithelial cells. Furthermore, solid tumours often present spatial and temporal heterogeneity in antigen expression due to genetic instability and microenvironmental cues[80-82].
To overcome these limitations, researchers have redirected CAR-T cells toward targeting the stromal compartment of solid tumours, particularly CAFs, which are abundant, genetically stable, and immunosuppressive[83]. A promising target in this context is FAP, a membrane-bound serine protease selectively expressed in activated myofibroblasts and CAFs. FAP expression is minimal in most healthy adult tissues but is upregulated in fibrosis and various solid tumors[79]. FAP-specific CAR-T cells have demonstrated efficacy in preclinical cancer models. A CAR incorporating the MO36 single-chain variable fragment, CD28, and CD3ζ signaling domains successfully reduced tumor burden and improved survival in an A549 lung cancer model[84]. Another CAR using the 73.3 single-chain variable fragment, along with CD8 stalk and 4-1BB signaling domains, led to 35%-50% tumor growth reduction in multiple mouse models[85].
To improve safety, a modified CAR lacking the Lck-binding site in the CD28 domain (F19-ΔCD28/CD3ζ) was developed. This design limited IL-2 secretion and reduced regulatory T cell expansion. It retained potent anti-tumor effects against FAP-positive mesothelioma cells and entered a phase I clinical trial. Combining this CAR with PD-1 checkpoint blockade further enhanced tumor regression in a humanized mouse model[86,87]. A clinical trial (NCT03932565) is also evaluating a fourth-generation CAR-T therapy targeting both Nectin4 and FAP in solid tumors, including triple-negative breast, pancreatic, and ovarian cancers. This design includes inducible cytokine expression (IL-7, C-C motif chemokine ligand 19, or IL-12) to support immune cell recruitment and function[88].
In pancreatic ductal adenocarcinoma, a sequential CAR-T approach has shown encouraging results. FAP-specific CAR-T cells were administered first to deplete the fibrotic stroma, followed by CAR-T cells targeting Claudin 18.2 on cancer cells. This combination allowed deeper immune cell infiltration and improved tumor control compared to either strategy alone[89]. In non-cancerous settings, FAP-targeted CAR-T cells have also been evaluated in a mouse model of cardiac fibrosis. Transient expression of FAP-CARs in T cells led to selective elimination of activated cardiac fibroblasts, reduced fibrosis, and improved cardiac function without significant off-target effects[90].
FAP-targeted CAR-T therapies offer a novel strategy for dismantling the fibrotic stroma that supports tumour progression and immune evasion. By eliminating activated myofibroblasts and CAFs, these therapies enhance immune infiltration, drug delivery, and overall treatment response. Their dual applicability in both malignant and non-malignant fibrotic diseases highlights their translational potential, though clinical safety and antigen specificity must be carefully managed.
SENOLYTICS
Activated fibroblasts, including CAFs and myofibroblasts in fibrotic tissues, often exhibit senescent-like features. These include resistance to apoptosis, altered secretory profiles, and the production of pro-fibrotic and immunosuppressive factors[91]. Senescent fibroblasts contribute to excessive ECM deposition, stromal stiffening, and reduced efficacy of therapies by promoting immune evasion and sustaining a fibrotic microenvironment.
Another promising agent is the forkhead box O4 (FOXO4) peptide, which disrupts the interaction between FOXO4 and p53. This interference induces p53-dependent apoptosis specifically in senescent fibroblasts. In keloid fibrosis, this mechanism effectively eliminated senescent myofibroblasts by promoting nuclear export of p53 and activation of intrinsic apoptotic pathways[92]. The combination of dasatinib and quercetin (D + Q) has been widely studied for its synergistic senolytic effects. In a bleomycin-induced lung fibrosis model, D + Q treatment significantly reduced senescent cell burden, improved lung function, and decreased fibrosis severity[93]. These results support the utility of combinatorial senolytics in treating fibrotic lung disease.
Heat shock protein 90 (HSP90) inhibitors, such as 17-Dimethylaminoethylamino-17-demethoxygeldanamycin, have also demonstrated senolytic activity in murine fibroblast models. Treatment with 17-Dimethylaminoethylamino-17-demethoxygeldanamycin in a progeroid mouse model improved health span and reduced markers of senescence, underscoring HSP90’s potential as a therapeutic target in age-related and fibrotic pathologies[94]. Despite their promise, senolytic agents may inadvertently affect healthy, non-senescent cells that transiently express senescence-associated markers under stress. This raises concerns regarding off-target cytotoxicity. For example, navitoclax has been associated with dose- limiting thrombocytopenia due to its inhibition of BCL-XL, a protein essential for platelet survival[95]. Additionally, broad inhibition of pathways such as HSP90 can impair normal cellular functions involved in proteostasis and stress response[96]. Senolytics such as navitoclax, FOXO4 peptides, D + Q, and HSP90 inhibitors provide an innovative strategy to eliminate senescent, fibrosis-promoting fibroblasts. These agents could enhance therapeutic responses by reducing stromal resistance and inflammation. However, the risk of toxicity to healthy tissues highlights the need for selective delivery and further safety optimization in clinical settings.
CONCLUSION
Myofibroblasts stand at the intersection of tissue repair, fibrosis, and cancer progression, making them pivotal yet complex therapeutic targets. While their transient activation is essential for wound healing, their sustained presence contributes to chronic fibrotic disorders and enhances the rigidity and immune evasion of the TME. Recent advances in understanding myofibroblast heterogeneity, plasticity, and cross-talk with other cells have ushered in new therapeutic possibilities. Strategies such as mitochondrial reprogramming, inhibition of pro-survival signaling, redox modulation, immune checkpoint targeting, and senolytics are being explored to selectively eliminate or inactivate pathogenic myofibroblasts. Approaches like BH3 mimetics, FAK/ROCK inhibitors, CAR-T therapies, and antioxidant modulation have shown promising results in preclinical models of fibrosis and cancer. Despite these developments, clinical translation remains challenging. Off-target toxicity, preservation of physiological fibroblast functions, and integration with existing treatments are key considerations. As translational research continues to bridge laboratory insights with patient outcomes, precision therapies targeting myofibroblasts hold strong potential to not only halt disease progression but also restore tissue homeostasis and improve treatment responsiveness.
ACKNOWLEDGEMENTS
The author gratefully acknowledges the support and contributions of colleagues R. Rabitha and Shivani S during the preparation of this review. Their insights and assistance were valuable in shaping this manuscript.
Footnotes
Provenance and peer review: Invited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Oncology
Country of origin: India
Peer-review report’s classification
Scientific Quality: Grade A, Grade B
Novelty: Grade B, Grade B
Creativity or Innovation: Grade B, Grade B
Scientific Significance: Grade B, Grade B
P-Reviewer: Chen YZ, PhD, Postdoctoral Fellow, China S-Editor: Bai Y L-Editor: A P-Editor: Zhang YL
Soumyakrishnan S, Divya T, Kalayarasan S, Sriram N, Sudhandiran G. Daidzein exhibits anti-fibrotic effect by reducing the expressions of Proteinase activated receptor 2 and TGFβ1/smad mediated inflammation and apoptosis in Bleomycin-induced experimental pulmonary fibrosis.Biochimie. 2014;103:23-36.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 30][Cited by in RCA: 47][Article Influence: 4.3][Reference Citation Analysis (0)]
Öhlund D, Handly-Santana A, Biffi G, Elyada E, Almeida AS, Ponz-Sarvise M, Corbo V, Oni TE, Hearn SA, Lee EJ, Chio II, Hwang CI, Tiriac H, Baker LA, Engle DD, Feig C, Kultti A, Egeblad M, Fearon DT, Crawford JM, Clevers H, Park Y, Tuveson DA. Distinct populations of inflammatory fibroblasts and myofibroblasts in pancreatic cancer.J Exp Med. 2017;214:579-596.
[RCA] [PubMed] [DOI] [Full Text] [Full Text (PDF)][Cited by in Crossref: 1020][Cited by in RCA: 1858][Article Influence: 232.3][Reference Citation Analysis (0)]
Verteporfin In Photodynamic Therapy Study Group. Verteporfin therapy of subfoveal choroidal neovascularization in age-related macular degeneration: two-year results of a randomized clinical trial including lesions with occult with no classic choroidal neovascularization--verteporfin in photodynamic therapy report 2.Am J Ophthalmol. 2001;131:541-560.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 655][Cited by in RCA: 690][Article Influence: 28.8][Reference Citation Analysis (0)]
Lagares D, Santos A, Grasberger PE, Liu F, Probst CK, Rahimi RA, Sakai N, Kuehl T, Ryan J, Bhola P, Montero J, Kapoor M, Baron M, Varelas X, Tschumperlin DJ, Letai A, Tager AM. Targeted apoptosis of myofibroblasts with the BH3 mimetic ABT-263 reverses established fibrosis.Sci Transl Med. 2017;9:eaal3765.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 135][Cited by in RCA: 182][Article Influence: 22.8][Reference Citation Analysis (0)]
Lagares D, Busnadiego O, García-Fernández RA, Kapoor M, Liu S, Carter DE, Abraham D, Shi-Wen X, Carreira P, Fontaine BA, Shea BS, Tager AM, Leask A, Lamas S, Rodríguez-Pascual F. Inhibition of focal adhesion kinase prevents experimental lung fibrosis and myofibroblast formation.Arthritis Rheum. 2012;64:1653-1664.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 117][Cited by in RCA: 144][Article Influence: 11.1][Reference Citation Analysis (0)]
Wang LC, Lo A, Scholler J, Sun J, Majumdar RS, Kapoor V, Antzis M, Cotner CE, Johnson LA, Durham AC, Solomides CC, June CH, Puré E, Albelda SM. Targeting fibroblast activation protein in tumor stroma with chimeric antigen receptor T cells can inhibit tumor growth and augment host immunity without severe toxicity.Cancer Immunol Res. 2014;2:154-166.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 404][Cited by in RCA: 523][Article Influence: 47.5][Reference Citation Analysis (0)]
Gulati P, Rühl J, Kannan A, Pircher M, Schuberth P, Nytko KJ, Pruschy M, Sulser S, Haefner M, Jensen S, Soltermann A, Jungraithmayr W, Eisenring M, Winder T, Samaras P, Tabor A, Stenger R, Stupp R, Weder W, Renner C, Münz C, Petrausch U. Aberrant Lck Signal via CD28 Costimulation Augments Antigen-Specific Functionality and Tumor Control by Redirected T Cells with PD-1 Blockade in Humanized Mice.Clin Cancer Res. 2018;24:3981-3993.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 30][Cited by in RCA: 61][Article Influence: 8.7][Reference Citation Analysis (0)]
Aghajanian H, Kimura T, Rurik JG, Hancock AS, Leibowitz MS, Li L, Scholler J, Monslow J, Lo A, Han W, Wang T, Bedi K, Morley MP, Linares Saldana RA, Bolar NA, McDaid K, Assenmacher CA, Smith CL, Wirth D, June CH, Margulies KB, Jain R, Puré E, Albelda SM, Epstein JA. Targeting cardiac fibrosis with engineered T cells.Nature. 2019;573:430-433.
[RCA] [PubMed] [DOI] [Full Text] [Full Text (PDF)][Cited by in Crossref: 229][Cited by in RCA: 569][Article Influence: 94.8][Reference Citation Analysis (0)]
de Vos S, Leonard JP, Friedberg JW, Zain J, Dunleavy K, Humerickhouse R, Hayslip J, Pesko J, Wilson WH. Safety and efficacy of navitoclax, a BCL-2 and BCL-X(L) inhibitor, in patients with relapsed or refractory lymphoid malignancies: results from a phase 2a study.Leuk Lymphoma. 2021;62:810-818.
[RCA] [PubMed] [DOI] [Full Text][Cited by in Crossref: 29][Cited by in RCA: 63][Article Influence: 15.8][Reference Citation Analysis (0)]
