Interplay and therapeutic implications of colorectal cancer stem cells, tumor microenvironment, and gut microbiota

Abstract

This article discusses the interplay between colorectal cancer (CRC) stem cells, tumor microenvironment (TME), and gut microbiota, emphasizing their dynamic roles in cancer progression and treatment resistance. It highlights the adaptability of CRC stem cells, the bidirectional influence of TME, and the multifaceted impact of gut microbiota on CRC. The manuscript proposes innovative therapeutic strategies focusing on these interactions, advocating for a shift towards personalized and ecosystem-targeted treatments in CRC. The conclusion underscores the importance of continued research in these areas for developing effective, personalized therapies.

Key Words: Colorectal cancer; Stem cells; Tumor microenvironment; Gut microbiota; Treatment resistance; Therapeutic strategies; Personalized medicine; Cancer ecosystem; Research advancements

Core Tip: The core objective of this article is to build upon the compelling arguments presented in the review, highlighting emerging trends, and introducing fresh perspectives to delve deeper into the intricacies of the interplay among these factors. A profound understanding of this interactive relationship is of paramount importance, as it holds the key to unlocking entirely new colorectal cancer treatment strategies and significantly improving patient prognosis.

TO THE EDITOR

The recent review in the World Journal of Stem Cells on the complex interplay among the tumor microenvironment (TME), gut microbiota, and the stemness of colorectal cancer (CRC) cells offers a profound insight into the evolving landscape of CRC research[1]. This article aims to build upon the compelling narrative presented in the review, highlighting emerging trends and offering novel perspectives that could further elucidate the intricate relationship between these factors. Understanding this interplay is crucial, as it holds the key to unlocking new therapeutic strategies and improving patient outcomes in CRC (Figure 1).

Figure 1 The schematic diagram of multi-cell-cell communication in colon epithelium and colon adenocarcinoma. Arrows indicate the activation interactions between different cells (left). Under the influence of intestinal microorganisms, carcinoma in situ may progress to invasive cancer (right).

Discussion on CRC stem cells

In addressing the complex nature of CRC stem cells, it’s crucial to emphasize their dynamic role in tumor progression and therapy resistance. Recent studies have unveiled that CRC stem cells are not a static entity but are highly influenced by their microenvironment[2-4]. This adaptive nature complicates treatment strategies, as these cells can evade conventional therapies by altering their characteristics. Moreover, the heterogeneity within the stem cell population in CRC presents an additional layer of complexity, necessitating a more nuanced approach in therapeutic development. Understanding the molecular mechanisms driving this plasticity is paramount for devising effective treatments that can target these elusive cells[5-7].

Role of the TME

The TME plays a pivotal role in the pathogenesis of CRC[8], particularly in how it shapes the behavior of CRC stem cells. The interplay between CRC stem cells and their microenvironment is a dance of mutual influence, where TME not only nurtures stem cells but also undergoes modifications instigated by these cells[9]. This bidirectional communication is key in understanding tumor progression and resistance to therapy. Recent research highlights the importance of TME components such as immune cells, stromal cells, and extracellular matrix in modulating CRC stem cell functions[10]. These insights offer new avenues for therapeutic intervention, targeting not just the cancer cells but also their supporting environment.

Impact of gut microbiota

The gut microbiota’s role in CRC has gained significant attention, providing new insights into cancer biology and potential treatment modalities[11-13]. Research indicates that the gut microbiota influences CRC development and progression, possibly through interactions with CRC stem cells and the TME[14]. These microorganisms can affect immune responses, metabolic pathways, and even genetic stability within the tumor, suggesting a multifaceted impact on cancer dynamics. Understanding these mechanisms is crucial for developing innovative treatments that could leverage gut microbiota modulation, potentially offering a novel and less invasive approach to combating CRC.

Emerging therapeutic strategies

The evolving understanding of the interplay between CRC stem cells, the TME, and gut microbiota opens up new frontiers for therapeutic strategies. Targeting these complex interactions offers a promising avenue for more effective treatments. Recent advancements propose interventions like microbiota modulation, immune therapy tailored to the TME, and drugs targeting stem cell pathways[6,15,16]. These strategies represent a paradigm shift from conventional chemotherapy to more personalized and holistic approaches, aiming to disrupt the supportive network that fuels CRC progression. The potential of these therapies lies not just in their direct anticancer effects, but also in their ability to reshape the tumor landscape, making it less conducive to cancer growth and resistance.

Conclusion

In conclusion, the intricate interplay between CRC stem cells, the TME, and gut microbiota presents a fascinating yet complex puzzle in the realm of CRC research. The insights gleaned from recent studies not only enhance our understanding of CRC pathogenesis but also pave the way for innovative therapeutic approaches (Table 1). Embracing these new paradigms, which focus on targeting the cancer ecosystem as a whole, could significantly improve treatment outcomes. It is imperative that future research continues to unravel these complex relationships, as they hold the key to unlocking more effective and personalized CRC therapies.

Table 1 Microbial influences in colorectal cancer: Species, pathways, and therapeutic potential.

Microbial species	Role in colorectal cancer	Associated molecular pathways	Expression in CRC patients (↑/↓)	Potential therapeutic target (yes/no)	Notes	Ref.
Bacteroides fragilis	Promotes tumor growth and inflammation	TLR4/NF-κB signaling pathway	↑	Yes	Enterotoxigenic strains significant	[17]
Fusobacterium nucleatum	Increases cell proliferation and adhesion	FadA adhesion, E-cadherin activation	↑	Yes	Linked to tumor progression	[18]
Escherichia coli (pks+)	Induces genotoxicity and DNA damage	Colibactin production, DNA double-strand breaks	↑	No	pks+ strains carry colibactin genes	[19]
Faecalibacterium prausnitzii	Exhibits anti-inflammatory properties	Short-chain fatty acid production, IL-10 stimulation	↓	Yes	Protective role in gut health	[20]
Streptococcus gallolyticus	Associated with tumor development	Unknown	↑	No	Correlation with CRC, mechanisms unclear	[21]
Enterococcus faecalis	Promotes oxidative stress and DNA damage	Production of extracellular superoxide	↑	Yes	Role in early-stage CRC	[22]

CRC: Colorectal cancer; TLR4: Toll-like receptor 4; NF-κB: Nuclear factor kappa-B; IL: Interleukin.

ACKNOWLEDGEMENTS

We would like to thank our colleagues Zhi-Peng Li, Yu-Hua Ruan, and Peng Wang for their review of this manuscript and their support with the data. We also appreciate the reviewers and editorial staff members who contributed to the review and editing of this manuscript.