Matrix stiffening and acquired resistance to chemotherapy: concepts and clinical significance

YAP-LAMB3 axis dictates cellular resistance of pancreatic ductal adenocarcinoma cells to gemcitabine

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors with poor prognosis and inadequate response to treatment, such as gemcitabine (Gem), the first-line chemotherapeutic drug. Understanding the molecular determinants that control drug resistance to Gem is critical to predict potentially responsive patients and improve the benefits of Gem therapy. Emerging evidence suggests that certain developmental pathways, such as Hippo signaling, are aberrated and play important roles in Gem resistance in cancers. Although Hippo signaling has been reported to play a role in chemoresistance in cancers, it has not been clarified which specific target gene(s) functionally mediates the effect. In the present study, we found that YAP serves as a potent barrier for the cellular sensitivity of PDAC cells to Gem. We then identified and characterized laminin subunit beta 3 (LAMB3) as a bona fide target of YAP-TEAD4 to amplify YAP signaling via a feedback loop. Such a YAP-LAMB3 axis is critical to induce epithelial-mesenchymal transition and mediate Gem resistance. Taken together, we uncovered that YAP-LAMB3 axis is an important regulator of Gem, thus providing potential therapeutic targets for overcoming Gem resistance in PDAC.

Critical appraisal of the chorioallantoic membrane model for studying angiogenesis in preclinical research

BACKGROUND

Angiogenesis, the biological mechanism by which new blood vessels are generated from existing ones, plays a vital role in growth and development. Effective preclinical screening is necessary for the development of medications that may enhance or inhibit angiogenesis in the setting of different disorders. Traditional in vitro and, in vivo models of angiogenesis are laborious and time-consuming, necessitating advanced infrastructure for embryo culture.

MAIN BODY

A challenge encountered by researchers studying angiogenesis is the lack of appropriate techniques to evaluate the impact of regulators on the angiogenic response. An ideal test should possess reliability, technical simplicity, easy quantifiability, and, most importantly, physiological relevance. The CAM model, leveraging the extraembryonic membrane of the chicken embryo, offers a unique combination of accessibility, low cost, and rapid development, making it an attractive option for angiogenesis assays. This review evaluates the strengths and limitations of the CAM model in the context of its anatomical and physiological properties, and its relevance to human pathophysiological conditions. Its abundant capillary network makes it a common choice for studying angiogenesis. The CAM assay serves as a substitute for animal models and offers a natural setting for developing blood vessels and the many elements involved in the intricate interaction with the host. Despite its advantages, the CAM model's limitations are notable. These include species-specific responses that may not always extrapolate to humans and the ethical considerations of using avian embryos. We discuss methodological adaptations that can mitigate some of these limitations and propose future directions to enhance the translational relevance of this model. This review underscores the CAM model's valuable role in angiogenesis research and aims to guide researchers in optimizing its use for more predictive and robust preclinical studies.

CONCLUSION

The highly vascularized chorioallantoic membrane (CAM) of fertilized chicken eggs is a cost-effective and easily available method for screening angiogenesis, in comparison to other animal models.

Functional gene signature offers a powerful tool for characterizing clinicopathological features and depicting tumor immune microenvironment of colorectal cancer

BACKGROUND

Colorectal cancer, a prevalent malignancy worldwide, poses a significant challenge due to the lack of effective prognostic tools. In this study, we aimed to develop a functional gene signature to stratify colorectal cancer patients into different groups with distinct characteristics, which will greatly facilitate disease prediction.

RESULTS

Patients were stratified into high- and low-risk groups using a prediction model built based on the functional gene signature. This innovative approach not only predicts clinicopathological features but also reveals tumor immune microenvironment types and responses to immunotherapy. The study reveals that patients in the high-risk group exhibit poorer pathological features, including invasion depth, lymph node metastasis, and distant metastasis, as well as unfavorable survival outcomes in terms of overall survival and disease-free survival. The underlying mechanisms for these observations are attributed to upregulated tumor-related signaling pathways, increased infiltration of pro-tumor immune cells, decreased infiltration of anti-tumor immune cells, and a lower tumor mutation burden. Consequently, patients in the high-risk group exhibit a diminished response to immunotherapy. Furthermore, the high-risk group demonstrates enrichment in extracellular matrix-related functions and significant infiltration of cancer-associated fibroblasts (CAFs). Single-cell transcriptional data analysis identifies CAFs as the primary cellular type expressing hub genes, namely ACTA2, TPM2, MYL9, and TAGLN. This finding is further validated through multiple approaches, including multiplex immunohistochemistry (mIHC), polymerase chain reaction (PCR), and western blot analysis. Notably, TPM2 emerges as a potential biomarker for identifying CAFs in colorectal cancer, distinguishing them from both colorectal cancer cell lines and normal colon epithelial cell lines. Co-culture of CAFs and colorectal cancer cells revealed that CAFs could enhance the tumorigenic biofunctions of cancer cells indirectly, which could be partially inhibited by knocking down CAF original TPM2 expression.

CONCLUSIONS

This study introduces a functional gene signature that effectively and reliably predicts clinicopathological features and the tumor immune microenvironment in colorectal cancer. Moreover, the identification of TPM2 as a potential biomarker for CAFs holds promising implications for future research and clinical applications in the field of colorectal cancer.

Extracellular Matrix Components and Mechanosensing Pathways in Health and Disease

Glycosaminoglycans (GAGs) and proteoglycans (PGs) are essential components of the extracellular matrix (ECM) with pivotal roles in cellular mechanosensing pathways. GAGs, such as heparan sulfate (HS) and chondroitin sulfate (CS), interact with various cell surface receptors, including integrins and receptor tyrosine kinases, to modulate cellular responses to mechanical stimuli. PGs, comprising a core protein with covalently attached GAG chains, serve as dynamic regulators of tissue mechanics and cell behavior, thereby playing a crucial role in maintaining tissue homeostasis. Dysregulation of GAG/PG-mediated mechanosensing pathways is implicated in numerous pathological conditions, including cancer and inflammation. Understanding the intricate mechanisms by which GAGs and PGs modulate cellular responses to mechanical forces holds promise for developing novel therapeutic strategies targeting mechanotransduction pathways in disease. This comprehensive overview underscores the importance of GAGs and PGs as key mediators of mechanosensing in maintaining tissue homeostasis and their potential as therapeutic targets for mitigating mechano-driven pathologies, focusing on cancer and inflammation.

Coating Dormant Collagenase-Producing Bacteria with Metal-Anesthetic Networks for Precision Tumor Therapy

Tumor malignancy highly depends on the stiffness of tumor matrix, which mainly consists of collagen. Despite the destruction of tumor matrix is conducive to tumor therapy, it causes the risk of tumor metastasis. Here, metal-anesthetic network-coated dormant collagenase-producing Clostridium is constructed to simultaneously destruct tumor matrix and inhibit tumor metastasis. By metal-phenolic complexation and π-π stacking interactions, a Fe3+-propofol network is formed on bacterial surface. Coated dormant Clostridium can selectively germinate and rapidly proliferate in tumor sites due to the ability of carried Fe3+ ions to promote bacterial multiplication. Intratumoral colonization of Clostridium produces sufficient collagenases to degrade tumor collagen mesh and the loaded propofol restrains tumor metastasis by inhibiting tumor cell migration and invasion. Meanwhile, the delivered Fe3+ ions are reduced to the Fe2+ form by intracellular glutathione, thereby inducing potent Fenton reaction to trigger lipid peroxidation and ultimate ferroptosis of tumor cells. In addition to a satisfactory safety, a single intratumoral injection of coated dormant Clostridium not only effectively retards the growth of established large primary tumors, but also significantly suppresses distal lung metastasis in two different orthotopic tumor models. This work proposes a strategy to develop advanced therapeutics for malignant tumor treatment and metastasis prevention.

The Interplay between Extracellular Matrix Remodeling and Cancer Therapeutics

The extracellular matrix (ECM) is an abundant noncellular component of most solid tumors known to support tumor progression and metastasis. The interplay between the ECM and cancer therapeutics opens up new avenues in understanding cancer biology. While the ECM is known to protect the tumor from anticancer agents by serving as a biomechanical barrier, emerging studies show that various cancer therapies induce ECM remodeling, resulting in therapy resistance and tumor progression. This review discusses critical issues in this field including how the ECM influences treatment outcome, how cancer therapies affect ECM remodeling, and the challenges associated with targeting the ECM. Significance: The intricate relationship between the extracellular matrix (ECM) and cancer therapeutics reveals novel insights into tumor biology and its effective treatment. While the ECM may protect tumors from anti-cancer agents, recent research highlights the paradoxical role of therapy-induced ECM remodeling in promoting treatment resistance and tumor progression. This review explores the key aspects of the interplay between ECM and cancer therapeutics.

The Role of TAMs in the Regulation of Tumor Cell Resistance to Chemotherapy

Tumor-associated macrophages (TAMs) are the predominant cell infiltrate in the immunosuppressive tumor microenvironment (TME). TAMs are central to fostering pro-inflammatory conditions, tumor growth, metastasis, and inhibiting therapy responses. Many cancer patients are innately refractory to chemotherapy and or develop resistance following initial treatments. There is a clinical correlation between the level of TAMs in the TME and chemoresistance. Hence, the pivotal role of TAMs in contributing to chemoresistance has garnered significant attention toward targeting TAMs to reverse this resistance. A prerequisite for such an approach requires a thorough understanding of the various underlying mechanisms by which TAMs inhibit response to chemotherapeutic drugs. Such mechanisms include enhancing drug efflux, regulating drug metabolism and detoxification, supporting cancer stem cell (CSCs) resistance, promoting epithelial-mesenchymal transition (EMT), inhibiting drug penetration and its metabolism, stimulating angiogenesis, impacting inhibitory STAT3/NF-κB survival pathways, and releasing specific inhibitory cytokines including TGF-β and IL-10. Accordingly, several strategies have been developed to overcome TAM-modulated chemoresistance. These include novel therapies that aim to deplete TAMs, repolarize them toward the anti-tumor M1-like phenotype, or block recruitment of monocytes into the TME. Current results from TAM-targeted treatments have been unimpressive; however, the use of TAM-targeted therapies in combination appears promising These include targeting TAMs with radiotherapy, chemotherapy, chemokine receptor inhibitors, immunotherapy, and loaded nanoparticles. The clinical limitations of these strategies are discussed.

Beyond matrix stiffness: targeting force-induced cancer drug resistance

During tumor progression, mechanical abnormalities in the tumor microenvironment (TME) trigger signaling pathways in cells that activate cellular programs, resulting in tumor growth and drug resistance. In this review, we describe mechanisms of action for anti-cancer therapies and mechanotransduction programs that regulate cellular processes, including cell proliferation, apoptosis, survival and phenotype switching. We discuss how the therapeutic response is impacted by the three main mechanical TME abnormalities: high extracellular matrix (ECM) composition and stiffness; interstitial fluid pressure (IFP); and elevated mechanical forces. We also review drugs that normalize these abnormalities or block mechanosensors and mechanotransduction pathways. Finally, we discuss current challenges and perspectives for the development of new strategies targeting mechanically induced drug resistance in the clinic.

Prognostic Significance of Integrin Subunit Alpha 2 (ITGA2) and Role of Mechanical Cues in Resistance to Gemcitabine in Pancreatic Ductal Adenocarcinoma (PDAC)

INTRODUCTION

PDAC is an extremely aggressive tumor with a poor prognosis and remarkable therapeutic resistance. The dense extracellular matrix (ECM) which characterizes PDAC progression is considered a fundamental determinant of chemoresistance, with major contributions from mechanical factors. This study combined biomechanical and pharmacological approaches to evaluate the role of the cell-adhesion molecule ITGA2, a key regulator of ECM, in PDAC resistance to gemcitabine.

METHODS

The prognostic value of ITGA2 was analysed in publicly available databases and tissue-microarrays of two cohorts of radically resected and metastatic patients treated with gemcitabine. PANC-1 and its gemcitabine-resistant clone (PANC-1R) were analysed by RNA-sequencing and label-free proteomics. The role of ITGA2 in migration, proliferation, and apoptosis was investigated using hydrogel-coated wells, siRNA-mediated knockdown and overexpression, while collagen-embedded spheroids assessed invasion and ECM remodeling.

RESULTS

High ITGA2 expression correlated with shorter progression-free and overall survival, supporting its impact on prognosis and the lack of efficacy of gemcitabine treatment. These findings were corroborated by transcriptomic and proteomic analyses showing that ITGA2 was upregulated in the PANC-1R clone. The aggressive behavior of these cells was significantly reduced by ITGA2 silencing both in vitro and in vivo, while PANC-1 cells growing under conditions resembling PDAC stiffness acquired resistance to gemcitabine, associated to increased ITGA2 expression. Collagen-embedded spheroids of PANC-1R showed a significant matrix remodeling and spreading potential via increased expression of CXCR4 and MMP2. Additionally, overexpression of ITGA2 in MiaPaCa-2 cells triggered gemcitabine resistance and increased proliferation, both in vitro and in vivo, associated to upregulation of phospho-AKT.

CONCLUSIONS

ITGA2 emerged as a new prognostic factor, highlighting the relevance of stroma mechanical properties as potential therapeutic targets to counteract gemcitabine resistance in PDAC.

Functional and clinical characteristics of focal adhesion kinases in cancer progression

Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase and an adaptor protein that primarily regulates adhesion signaling and cell migration. FAK promotes cell survival in response to stress. Increasing evidence has shown that at the pathological level, FAK is highly expressed in multiple tumors in several systems (including lung, liver, gastric, and colorectal cancers) and correlates with tumor aggressiveness and patient prognosis. At the molecular level, FAK promotes tumor progression mainly by altering survival signals, invasive capacity, epithelial-mesenchymal transition, the tumor microenvironment, the Warburg effect, and stemness of tumor cells. Many effective drugs have been developed based on the comprehensive role of FAK in tumor cells. In addition, its potential as a tumor marker cannot be ignored. Here, we discuss the pathological and pre-clinical evidence of the role of FAK in cancer development; we hope that these findings will assist in FAK-based clinical studies.

The Extracellular Matrix and Neuroblastoma Cell Communication-A Complex Interplay and Its Therapeutic Implications

Neuroblastoma (NB) is a pediatric neuroendocrine neoplasm. It arises from the sympatho-adrenal lineage of neural-crest-derived multipotent progenitor cells that fail to differentiate. NB is the most common extracranial tumor in children, and it manifests undisputed heterogeneity. Unsatisfactory outcomes of high-risk (HR) NB patients call for more research to further inter-relate treatment and molecular features of the disease. In this regard, it is well established that in the tumor microenvironment (TME), malignant cells are engaged in complex and dynamic interactions with the extracellular matrix (ECM) and stromal cells. The ECM can be a source of both pro- and anti-tumorigenic factors to regulate tumor cell fate, such as survival, proliferation, and resistance to therapy. Moreover, the ECM composition, organization, and resulting signaling networks are vastly remodeled during tumor progression and metastasis. This review mainly focuses on the molecular mechanisms and effects of interactions of selected ECM components with their receptors on neuroblastoma cells. Additionally, it describes roles of enzymes modifying and degrading ECM in NB. Finally, the article gives examples on how the knowledge is exploited for prognosis and to yield new treatment options for NB patients.

Myofibroblastic CAF Density, Not Activated Stroma Index, Indicates Prognosis after Neoadjuvant Therapy of Pancreatic Carcinoma

Neoadjuvant therapy (NT) for advanced PDAC is an emerging concept, affecting both stroma and tumor. The Activated Stroma Index (ASI; ratio of activated cancer-associated fibroblasts (CAF) to collagen deposition) is a prognostic marker in upfront resected pancreatic adenocarcinoma (PDAC). We assessed ASI and its prognostic relevance after NT. Tissue from resection specimens of n = 48 PDAC patients after neoadjuvant chemotherapy with FOLFIRINOX (FOL; n = 31), gemcitabine + nab-paclitaxel (GEM; 7) or combination treatment (COMB; 10) was compared with upfront resected matched controls (RES; 69). Activated CAFs were assessed by immunohistochemistry for α-SMA, and collagen was stained with aniline blue; the stained area was then determined by computational imaging analysis and ASI was calculated. In GEM, ASI was significantly higher and collagen deposition lower than in controls and FOL. The lowest quartile of ASI values had significantly longer overall survival (OS) in RES, whereas in FOL, the highest quartile had the best prognosis. After NT, OS was significantly improved in the α-SMA-high group; in RES, however, survival was independent of α-SMA. Reversed prognostic association of ASI thus points to the differing significance of stromal composition after FOL, while improved prognosis with high CAF abundance suggests a synergistic effect of myofibroblasts with chemotherapy. These divergences impede usability of ASI after NT.

The Role of Extracellular Matrix Remodeling in Skin Tumor Progression and Therapeutic Resistance

The extracellular matrix remodeling in the skin results from a delicate balance of synthesis and degradation of matrix components, ensuring tissue homeostasis. These processes are altered during tumor invasion and growth, generating a microenvironment that supports growth, invasion, and metastasis. Apart from the cellular component, the tumor microenvironment is rich in extracellular matrix components and bound factors that provide structure and signals to the tumor and stromal cells. The continuous remodeling in the tissue compartment sustains the developing tumor during the various phases providing matrices and proteolytic enzymes. These are produced by cancer cells and stromal fibroblasts. In addition to fostering tumor growth, the expression of specific extracellular matrix proteins and proteinases supports tumor invasion after the initial therapeutic response. Lately, the expression and structural modification of matrices were also associated with therapeutic resistance. This review will focus on the significant alterations in the extracellular matrix components and the function of metalloproteinases that influence skin cancer progression and support the acquisition of therapeutic resistance.