Secretome of Stromal Cancer-Associated Fibroblasts (CAFs): Relevance in Cancer

Roles of anoikis in hepatocellular carcinoma therapy and the assessment of anoikis-regulatory molecules as therapeutic targets

As the fourth leading cause of death from cancer and the sixth most common neoplasm in the world, hepatocellular carcinoma (HCC) is responsible for ninety percent of all primary liver cancers. There are four mechanisms that contribute to the spread of cancer: the separation of cells from the primary neoplasm, their survivability during metastasis, extravasation, and the development of secondary tumors at remote locations. In addition to its role in the development of a scaffold for cell adhesion, the extracellular matrix (ECM) also plays a role in the stimulation of signal transduction and the regulation of essential cellular mechanisms, including proliferation, migration, differentiation, and viability. The disruption of cell-ECM interactions and the ensuing separation of cells from the primary ECM trigger anoikis, a form of programmed cell death. One of the most effective factors in suppressing anoikis is ECM receptors from the integrin family. Cell migration, proliferation, and survival are primarily governed by the formation of physical connections with the cytoskeleton and the conveyance of signals between cells and the ECM via integrin receptors.

Decoding the MMP14 integrin link: Key player in the secretome landscape

Rapid progress has been made in the exciting field of secretome research in health and disease. The tumor secretome, which is a significant proportion of the tumor proteome, is secreted into the extracellular space to promote intercellular communication and thus tumor progression. Among the many molecules of the secretome, integrins and matrix metalloproteinase 14 (MMP14) stand out as the interplay of adhesion and proteolysis drives invasion. Integrins serve as mechanosensors that mediate the contact of cells with the scaffold of the extracellular matrix and are significantly involved in the precise positioning and activity control of the membrane-bound collagenase MMP14. As a secretome proteinase, MMP14 influences and modifies the secretome itself. While integrins and MT-MMPs are membrane bound, but can be released and are therefore border crossers between the cell surface and the secretome, the extracellular matrix is not constitutively cell-bound, but its binding to integrins and other cell receptors is a stringently regulated process. To understand the mutual interactions in detail, we first summarize the structure and function of MMP14 and how it is regulated at the enzymatic and cellular level. In particular, the mutual interactions between integrins and MMP14 include the proteolytic cleavage of integrins themselves by MMP14. We then review the biochemical, cell biological and physiological effects of MMP14 on the composition and associated functions in the tumor secretome when either bound to the cell membrane, or located on extracellular microvesicles, or as a proteolytically shed non-membrane-bound ectodomain. Novel methods of proteomics, including the analysis of extravesicular vesicles, and new methods for the quantification of MMP14 will provide new research and diagnostic tools. The proteolytic modification of the tumor secretome, especially by MMP14, may bring an additional aspect to tumor secretome studies and will have an impact on the diagnosis and most likely also on the therapy of cancer patients.

High α-SMA expression in the tumor stroma is associated with adverse clinical parameters in mismatch repair-proficient colorectal cancers only

OBJECTIVES

As mismatch repair status confers differential prognosis in colorectal cancers, this study aimed to determine associations of α-smooth muscle actin (α-SMA) protein expression in mismatch repair-proficient (pMMR) and mismatch repair-deficient (dMMR) colorectal tumors with clinicopathologic and prognostic features.

METHODS

Tissue microarrays from patients with colorectal cancer, immunostained with α-SMA, were assessed through digital image analysis. Total (n = 962), pMMR (n = 782), and dMMR (n = 156) stromal H-scores were assessed for associations with clinicopathologic and survival data.

RESULTS

Higher α-SMA expression was correlated with pMMR status (P = 5.2223 × 10-8). In the pMMR subgroup, higher α-SMA stromal expression at the tumor periphery was correlated with higher T stage (P = .002), perineural invasion (P = .038), infiltrative tumor edge (P = .01), involved nodal status (P = .036), metastases (P = .013), synchronous metastases (P = .007), recurrence (P = .004), and both 3-year and 5-year survival (P = .018). dMMR tumors showed no significant correlations with α-SMA staining.

CONCLUSIONS

The findings highlight that immunostaining with α-SMA in pMMR colorectal tumors, especially at the tumor periphery, has the potential to identify patients with adverse prognostic features. Digital assessment of α-SMA may offer improved objectivity, accuracy, economy of time, and risk stratification for management.

IFNγ and TNFα drive an inflammatory secretion profile in cancer-associated fibroblasts from human non-small cell lung cancer

Cancer-associated fibroblasts (CAFs) are the dominant nonmalignant component of the tumour microenvironment (TME). CAFs demonstrate a high level of inter- and intra-tumour heterogeneity in solid tumours, though the drivers of CAF subpopulations are not fully understood. Here, we demonstrate that non-small cell lung cancer (NSCLC) patient-derived CAFs upregulate the secretion of inflammatory cytokines (IL6, LIF, IL33, GM-CSF, IL1ra) and chemokines (CCL2, CCL3, CCL4, CCL20, CXCL8, CXCL9, CXCL10, CXCL11) in response to in vitro co-culture with anti-CD3/anti-CD28-stimulated peripheral blood mononuclear cells (PBMCs) via IFNγ and TNFα. Furthermore, T-cell-derived IFNγ inhibits CXCL12 secretion by CAFs in vitro. Our results highlight the ability of T-cell effector cytokines to modulate the CAF secretome in NSCLC.

Harnessing the tumor microenvironment: targeted cancer therapies through modulation of epithelial-mesenchymal transition

The tumor microenvironment (TME) is integral to cancer progression, impacting metastasis and treatment response. It consists of diverse cell types, extracellular matrix components, and signaling molecules that interact to promote tumor growth and therapeutic resistance. Elucidating the intricate interactions between cancer cells and the TME is crucial in understanding cancer progression and therapeutic challenges. A critical process induced by TME signaling is the epithelial-mesenchymal transition (EMT), wherein epithelial cells acquire mesenchymal traits, which enhance their motility and invasiveness and promote metastasis and cancer progression. By targeting various components of the TME, novel investigational strategies aim to disrupt the TME's contribution to the EMT, thereby improving treatment efficacy, addressing therapeutic resistance, and offering a nuanced approach to cancer therapy. This review scrutinizes the key players in the TME and the TME's contribution to the EMT, emphasizing avenues to therapeutically disrupt the interactions between the various TME components. Moreover, the article discusses the TME's implications for resistance mechanisms and highlights the current therapeutic strategies toward TME modulation along with potential caveats.

Influence of stromal neural crest progenitor cells on neuroblastoma radioresistance

PURPOSE

A substantial proportion of children with high risk Neuroblastoma die within the first 5 years post-diagnosis despite the complex treatment applied. In the recent years, tumor environment has been revealed as key factor for cancer treatment efficacy. In this sense, non-tumorigenic Neural Crest progenitor cells from high risk patients, have been described as part of Neuroblastoma stroma, promoting tumor growth and contributing to mesenchyme formation. In this paper we wanted to study the radiobiological behavior of these cells (NB14t) and how they influence the growth of tumorigenic neuroblasts after radiotherapy.

MATERIALS AND METHODS

To achieve our aim, we employed a wide list of methods either using NB14t cells as well as commercial NB cells. We have analyzed viability, survival, cell cyle profiles and differentiation. In addition, cocultured experiments were performed to monitor the influence of stroma cells to tumorigenic neuroblasts.

RESULTS

We found that stromal progenitor cells showed an extraordinary radio-resistance either cultured in attached or suspension conditions. In good agreement, we found an enhanced repair of irradiation-induced DNA lesions as compared with commercial cell lines. In addition, according to our data these cells differentiate into a Cancer Associated Fibroblasts (CAFs)-like phenotype, hence contributing to the formation of mesenchymal stroma enhancing the growth of tumor cells after irradiation.

CONCLUSION

Our data show that neural progenitor cells from high risk NB stroma are radio-resistant and promote cancer growth after irradiation. This paper can help to understand the complex cell relationships within a tumor that will determine patient prognosis after radiotherapy.

AMIGO2 characterizes cancer-associated fibroblasts in metastatic colon cancer and induces the release of paracrine active tumorigenic secretomes

Secretomes of cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC) contribute to malignancy. Detailed knowledge is available on the components and functions of CAF secretomes. Little is known about the regulation of CAF secretomes. Here, we searched for receptor-like membrane-bound molecules in CAFs, which may regulate the production and release of tumor-activating secretomes. The adhesion molecule with Ig-like domain 2 (AMIGO2) was significantly upregulated in cultivated CAFs compared to normal tissue-associated fibroblasts (NAFs), and this was confirmed in patient-derived tissues. AMIGO2 expression was low or absent in healthy colon, significantly increased in fibroblasts of primary CRC, and highest in the stromal tissues of CRC-derived liver metastases. AMIGO2 expression in CAFs correlated with a higher T-category, increased lymph node metastasis, progressed tumor stages and was associated with reduced survival in different cohorts of CRC patients. Interestingly, AMIGO2 expression was induced by transforming growth factor-β and higher in female patients, who exhibit a more aggressive disease course. In functional studies, conditioned media of NAFs with experimentally induced AMIGO2 overexpression enhanced proliferation and migration of different CRC tumor cells, while siRNA-mediated inhibition of AMIGO2 in CAFs attenuated these effects. Accordingly, therapeutic inhibition of the receptor-like AMIGO2 protein in CRC CAFs could prevent tumorigenic secretomes in CRC. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Comprehensive pan-cancer analysis reveals CDC6 as a potential immunomodulatory agent and promising therapeutic target in pancreatic cancer

Background

CDC6 is critical in DNA replication initiation, but its expression patterns and clinical implications in cancer are underexplored. This study uses multi-omics data from The Cancer Genome Atlas (TCGA) to comprehensively analyze CDC6 across various cancers, aiming to evaluate its potential as a prognostic biomarker and explore its role in immunotherapy.

Methods

By leveraging multi-omics data from TCGA, we conducted a comprehensive analysis of CDC6 expression across a variety of cancer types. Least absolute shrinkage and selection operator (LASSO) regression was employed to assess the association of CDC6 with key molecules implicated in pancreatic cancer.

Results

CDC6 expression was found to be significantly upregulated across a broad spectrum of cancers. High levels of CDC6 expression were associated with poor prognosis in several cancer types. Notable associations were observed between CDC6 expression and tumor mutational burden (TMB), microsatellite instability (MSI), as well as immune cell infiltration. Co-expression analysis revealed significant associations between CDC6 and prevalent immune checkpoint genes. A risk model incorporating CDC6-related genes, including CCNA1, CCNA2, CCND1, CCND2, CDC25B, CDC6, and CDK2, was developed for pancreatic cancer.

Conclusions

CDC6 emerges as a promising prognostic biomarker and a potential target for immunotherapy across various cancers, including pancreatic cancer. It appears to modulate immune responses across cancer types, highlighting its regulatory role. Further exploration into the biological functions and clinical implications of CDC6 is warranted.

Unraveling the relationship between anoikis-related genes and cancer-associated fibroblasts in liver hepatocellular carcinoma

This study intended to determine the molecular subtypes of liver hepatocellular carcinoma (LIHC) on the strength of anoikis-related genes (ARGs) and to assess their prognostic value and prospective relationship with immune cell infiltration and cancer-associated fibroblasts (CAFs). Univariate Cox regression analysis yielded 66 prognosis-related ARGs and classified LIHC into two distinct subtypes, with subtype A demonstrating overexpression of most prognosis-related ARGs and a significant survival disadvantage. Furthermore, a reliable prediction model was developed using ARGs to evaluate the risk of LIHC patients. This model served as an independent prognostic indicator and a quantitative tool for clinical prognostic prediction. Additionally, subtype-specific differences in immune cell infiltration were observed, and the risk score was potentially linked to immune-related characteristics. Moreover, the study identified a significant association between CAF score and LIHC prognosis, with a low CAF score indicating a favorable patient prognosis. In conclusion, this study reveals the molecular mechanisms underlying the development and progression of LIHC and identifies potential therapeutic targets for the disease.

A novel TGFbeta/TGILR axis mediates crosstalk between cancer-associated fibroblasts and tumor cells to drive gastric cancer progression

Transforming growth factor beta (TGFβ) signaling plays a critical role in tumorigenesis and metastasis. However, little is known about the biological function of TGFbeta-induced lncRNA in cancer. In this study, we discovered a novel TGFbeta-induced lncRNA, termed TGILR, whose function in cancer remains unknown to date. TGILR expression was directly activated by the canonical TGFbeta/SMAD3 signaling axis, and this activation is highly conserved in cancer. Clinical analysis showed that TGILR overexpression showed a significant correlation with lymph node metastasis and poor survival and was an independent prognostic factor in gastric cancer (GC). Depletion of TGILR caused an obvious inhibitory effect on GC cell proliferation, invasion, and epithelial-mesenchymal transition (EMT) in vitro and in vivo. More importantly, we demonstrated that TGFbeta signaling in GC was overactivated due to cancer-associated fibroblast (CAF) infiltration. Mechanistically, increased level of CAF-secreted TGFbeta activates TGFbeta signaling, leading to TGILR overexpression in GC cells. Meanwhile, TGILR overexpression inhibited the microRNA biogenesis of miR-1306 and miR-33a by interacting with TARBP2 and reducing its protein stability, thereby promoting GC progression via TCF4-mediated EMT signaling. In conclusion, CAF infiltration drives GC metastasis and EMT signaling through activating TGFbeta/TGILR axis. Targeted blocking of CAF-derived TGFbeta should be a promising anticancer strategy in GC.

Cancer-associated fibroblasts promote enzalutamide resistance and PD-L1 expression in prostate cancer through CCL5-CCR5 paracrine axis

Cancer-associated fibroblasts (CAFs) have been shown to play a key role in prostate cancer treatment resistance, but the role of CAFs in the initial course of enzalutamide therapy for prostate cancer remains unclear. Our research revealed that CAFs secrete CCL5, which promotes the upregulation of androgen receptor (AR) expression in prostate cancer cells, leading to resistance to enzalutamide therapy. Furthermore, CCL5 also enhances the expression of tumor programmed death-ligand 1 (PD-L1), resulting in immune escape. Mechanistically, CCL5 binds to the receptor CCR5 on prostate cancer cells and activates the AKT signaling pathway, leading to the upregulation of AR and PD-L1. The CCR5 antagonist maraviroc to inhibit the CAFs mediated CCL5 signaling pathway can effectively reduce the expression of AR and PD-L1, and improve the efficacy of enzalutamide. This study highlights a promising therapeutic approach targeting the CCL5-CCR5 signaling pathway to improve the effectiveness of enzalutamide.

Characterization of preovulatory follicular fluid secretome and its effects on equine oocytes during in vitro maturation

In vitro maturation (IVM) of oocytes is clinically used in horses to produce blastocysts but current conditions used for horses are suboptimal. We analyzed the composition of equine preovulatory follicular fluid (FF) secretome and tested its effects on meiotic competence and gene expression in oocytes subjected to IVM. Preovulatory FF was obtained, concentrated using ultrafiltration with cut-off of 10 kDa, and stored at -80 °C. The metabolic and proteomic composition was analyzed, and its ultrastructural composition was assessed by cryo-transmission microscopy. Oocytes obtained post-mortem or by ovum pick up (OPU) were subjected to IVM in the absence (control) or presence of 20 or 40 μg/ml (S20 or S40) of secretome. Oocytes were then analyzed for chromatin configuration or snap frozen for gene expression analysis. Proteomic analysis detected 255 proteins in the Equus caballus database, mostly related to the complement cascade and cholesterol metabolism. Metabolomic analysis yielded 14 metabolites and cryo-transmission electron microscopy analysis revealed the presence of extracellular vesicles (EVs). No significant differences were detected in maturation rates among treatments. However, the expression of GDF9 and BMP15 significantly increased in OPU-derived oocytes compared to post-mortem oocytes (fold increase ± SEM: 9.4 ± 0.1 vs. 1 ± 0.5 for BMP15 and 9.9 ± 0.3 vs. 1 ± 0.5 for GDF9, respectively; p < 0.05). Secretome addition increased the expression of TNFAIP6 in S40 regardless of the oocyte source. Further research is necessary to fully understand whether secretome addition influences the developmental competence of equine oocytes.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via exosomes in gastrointestinal tumors

Gastrointestinal (GI) tumors are a significant global health threat, with high rates of morbidity and mortality. Exosomes contain various biologically active molecules like nucleic acids, proteins, and lipids and can serve as messengers for intercellular communication. They play critical roles in the exchange of information between tumor cells and the tumor microenvironment (TME). The TME consists of mesenchymal cells and components of the extracellular matrix (ECM), with fibroblasts being the most abundant cell type in the tumor mesenchyme. Cancer-associated fibroblasts (CAFs) are derived from normal fibroblasts and mesenchymal stem cells that are activated in the TME. CAFs can secrete exosomes to modulate cell proliferation, invasion, migration, drug resistance, and other biological processes in tumors. Additionally, tumor cells can manipulate the function and behavior of fibroblasts through direct cell-cell interactions. This review provides a summary of the intercellular crosstalk between GI tumor cells and CAFs through exosomes, along with potential underlying mechanisms.

Voltage-gated sodium channels, sodium transport and progression of solid tumours

Sodium (Na+) concentration in solid tumours of different origin is highly dysregulated, and this corresponds to the aberrant expression of Na+ transporters. In particular, the α subunits of voltage gated Na+ channels (VGSCs) raise intracellular Na+ concentration ([Na+]i) in malignant cells, which influences the progression of solid tumours, predominantly driving cancer cells towards a more aggressive and metastatic phenotype. Conversely, re-expression of VGSC β subunits in cancer cells can either enhance tumour progression or promote anti-tumourigenic properties. Metastasis is the leading cause of cancer-related mortality, highlighting an important area of research which urgently requires improved therapeutic interventions. Here, we review the extent to which VGSC subunits are dysregulated in solid tumours, and consider the implications of such dysregulation on solid tumour progression. We discuss current understanding of VGSC-dependent mechanisms underlying increased invasive and metastatic potential of solid tumours, and how the complex relationship between the tumour microenvironment (TME) and VGSC expression may further drive tumour progression, in part due to the interplay of infiltrating immune cells, cancer-associated fibroblasts (CAFs) and insufficient supply of oxygen (hypoxia). Finally, we explore past and present clinical trials that investigate utilising existing VGSC modulators as potential pharmacological options to support adjuvant chemotherapies to prevent cancer recurrence. Such research demonstrates an exciting opportunity to repurpose therapeutics in order to improve the disease-free survival of patients with aggressive solid tumours.

Rimonabant and Cannabidiol Rewrite the Interactions between Breast Cancer Cells and Tumor Microenvironment

The spread of breast cancer to distant sites is the major cause of death in breast cancer patients. Increasing evidence supports the role of the tumor microenvironment (TME) in breast cancers, and its pathologic assessment has become a diagnostic and therapeutic tool. In the TME, a bidirectional interplay between tumor and stromal cells occurs, both at the primary and metastatic site. Hundreds of molecules, including cytokines, chemokines, and growth factors, contribute to this fine interaction to promote tumor spreading. Here, we investigated the effects of Rimonabant and Cannabidiol, known for their antitumor activity, on reprogramming the breast TME. Both compounds directly affect the activity of several pathways involved in breast cancer progression. To mimic tumor-stroma interactions during breast-to-lung metastasis, we investigated the effect of the compounds on growth factor secretion from metastatic breast cancer cells and normal and activated lung fibroblasts. In this setting, we demonstrated the anti-metastatic potential of the two compounds, and the membrane array analyses highlighted their ability to alter the release of factors involved in the autocrine and paracrine regulation of tumor proliferation, angiogenesis, and immune reprogramming. The results enforce the antitumor potential of Rimonabant and Cannabidiol, providing a novel potential tool for breast cancer TME management.