Targeting Tumour-Associated Fibroblasts in Cancers

Decoding the function of cancer-associated fibroblasts in osteosarcoma: Molecular pathways, therapeutic approaches and prognostic significance

Herein, we summarize the latest insights into osteosarcoma, the most prevalent primary malignant bone tumor, known for its aggressive nature, poor outcome, and especially poor prognosis when metastasis develops. Given recent research implicating the crucial role of the tumor microenvironment (TME) in osteosarcoma progression, cancer-associated fibroblasts (CAFs) emerged as key players. Through the secretion of cytokines, remodeling of the extracellular matrix (ECM), and cross-talk with osteosarcoma cells, CAFs collectively promote tumor growth, metastasis, and immune evasion. Exosomes derived from CAFs, which could also serve as important mediators of osteosarcoma progression, have been found to transport oncogenic lncRNAs like SNHG17 and linc00881. Moreover, some subtypes of CAFs, such as TOP2A + CAFs, have shown significant prognostic value for tumor aggressiveness. Thus, targeted CAFs was identified as a promising therapeutic modality, with strategies such as fibroblast activation protein (FAP) inhibition, TGF-β blockade, and CXCL12/CXCR4 axis inhibition demonstrating positive outcomes in preclinical models. The combination of CAF-targeted therapies with immunotherapies or chemotherapy has shown additional potential to reverse this CAF-induced resistance. Autophagy regulation in CAFs can be therapeutic opportunities for novel Interevent strategies.

Harnessing the Power of Nanocarriers to Exploit the Tumor Microenvironment for Enhanced Cancer Therapy

The tumor microenvironment (TME) has a major role in malignancy and its complex nature can mediate tumor survival, metastasis, immune evasion, and drug resistance. Thus, reprogramming or regulating the immunosuppressive TME has a significant contribution to make in cancer therapy. Targeting TME with nanocarriers (NCs) has been widely used to directly deliver anticancer drugs to control TME, which has revealed auspicious outcomes. TME can be reprogrammed by using a range of NCs to regulate immunosuppressive factors and activate immunostimulatory cells. Moreover, TME can be ameliorated via regulating the redox environment, oxygen content, and pH value of the tumor site. NCs have the capacity to provide site-specific delivery of therapeutic agents, controlled release, enhanced solubility and stability, decreased toxicities, and enhanced pharmacokinetics as well as biodistribution. Numerous NCs have demonstrated their potential by inducing distinct anticancer mechanisms by delivering a range of anticancer drugs in various preclinical studies, including metal NCs, liposomal NCs, solid lipid NCs, micelles, nanoemulsions, polymer-based NCs, dendrimers, nanoclays, nanocrystals, and many more. Some of them have already received US Food and Drug Administration approval, and some have entered different clinical phases. However, there are several challenges in NC-mediated TME targeting, including scale-up of NC-based cancer therapy, rapid clearance of NCs by the mononuclear phagocyte system, and TME heterogeneity. In order to harness the full potential of NCs in tumor treatment, there are several factors that need to be carefully studied, including optimization of drug loading into NCs, NC-associated immunogenicity, and biocompatibility for the successful translation of NC-based anticancer therapies into clinical practice. In this review, a range of NCs and their applications in drug delivery to remodel TME for cancer therapy are extensively discussed. Moreover, findings from numerous preclinical and clinical studies with these NCs are also highlighted.

CAF-derived exosomal LINC01711 promotes breast cancer progression by activating the miR-4510/NELFE axis and enhancing glycolysis

Breast cancer (BRCA) is among the most prevalent malignancies in women, characterized by a complex tumor microenvironment significantly influenced by cancer-associated fibroblasts (CAFs). CAFs contribute to tumor progression by secreting exosomes that can modulate cancer cell behavior. This study highlights how CAF-derived exosomes transmit the long non-coding RNA (lncRNA) LINC01711, which activates TXN through the miR-4510/NELFE axis, thereby enhancing glycolysis in BRCA cells. Utilizing BRCA single-cell sequencing data from the GEO database, the study employed dimensionality reduction, clustering, and cell annotation techniques to uncover the central role of NELFE in BRCA. Experimental findings revealed that LINC01711 is highly expressed in CAF-derived exosomes, which upregulate TXN via the miR-4510/NELFE axis, promoting the glycolytic pathway and subsequently increasing the proliferation, migration, and invasion potential of BRCA cells. These results shed light on a novel molecular mechanism underlying BRCA progression and suggest potential targets for therapeutic intervention.

Colorectal cancer peritoneal metastasis is promoted by tissue-specific fibroblasts that can arise in response to various local disorders

Peritoneal membrane injury induces the activation of local fibroblasts and tissue remodelling, which ultimately can progress to fibrosis. Metastasis of colorectal cancer (CRC) to the abdominal cavity results in such peritoneal damage. Patients with colorectal cancer peritoneal metastasis (CPM) have a particularly poor prognosis, and CPM tumours are characterised by a high infiltration of fibroblasts. Here, we characterised the molecular and functional features of these fibroblasts, and investigated their interaction with other cells in the peritoneal microenvironment. Primary fibroblasts were isolated from 89 patients with different malignant and benign disorders of the peritoneum. We performed comprehensive analyses of single-cell and transcriptome profiling, secretome characterization, and functional enzymatic activity. We were able to identify a peritoneum-specific fibroblast population that increases in response to different types of damage-inducing peritoneal pathologies, including metastasis. These fibroblasts are characterised by the IGFBP2-dependent expression of CD38, which mediates extracellular non-canonical adenosinergic activity and contributes to the suppression of macrophages and T cells. Importantly, peritoneal fibroblasts promoted the growth and invasiveness of tumour cells in a xenograft mouse model of peritoneal metastasis, highlighting their pro-tumorigenic role. Their specific gene signature was associated with poor prognosis in a dataset of 51 patients suffering from colorectal peritoneal metastasis. This study revealed that the CPM is infiltrated by a peritoneal fibroblast subtype, which is absent in healthy tissue, but also observed in benign peritoneal diseases. Given the limited therapeutic options for these patients, these pro-tumorigenic peritoneal fibroblasts could represent an attractive target for inhibiting the peritoneal spread of tumour cells.

Recent advances in the mechanisms of PD-L1 expression in gastric cancer: a review

In the progression of gastric cancer (GC), various cell types in the tumor microenvironment (TME) exhibit upregulated expression of programmed death ligand 1 (PD-L1), leading to impaired T-cell function and evasion of immune surveillance. Infection with H. pylori and EBV leads to increased PD-L1 expression in various cell types within TME, resulting in immune suppression and facilitating immune escape of GC cells. In the TME, mesenchymal stem cells (MSCs), M1-like tumor-associated macrophages (MI-like TAM), and myeloid-derived suppressor cells (MDSCs) contribute to the upregulation of PD-L1 expression in GC cells. Conversely, mast cells, M2-like tumor-associated macrophages (M2-like TAM), and tumor-associated neutrophils (TANs) exhibit elevated levels of PD-L1 expression in response to the influence of GC cells. Together, these factors collectively contribute to the upregulation of PD-L1 expression in GC. This review aims to provide a comprehensive summary of the cellular expression patterns of PD-L1 in GC and the underlying molecular mechanisms. Understanding the complex regulatory pathways governing PD-L1 expression may offer novel insights for the development of effective immunotherapeutic interventions.

Cancer-Associated Fibroblasts in Intrahepatic Cholangiocarcinoma: Insights into Origins, Heterogeneity, Lymphangiogenesis, and Peritoneal Metastasis

Intrahepatic cholangiocarcinoma (iCCA) denotes a rare, highly malignant, and heterogeneous class of primary liver adenocarcinomas exhibiting phenotypic characteristics of cholangiocyte differentiation. Among the distinctive pathological features of iCCA, one that differentiates the most common macroscopic subtype (eg, mass-forming type) of this hepatic tumor from conventional hepatocellular carcinoma is a prominent desmoplastic reaction manifested as a dense fibro-collagenous-enriched tumor stroma. Cancer-associated fibroblasts (CAFs) represent the most abundant mesenchymal cell type in the desmoplastic reaction. Although the protumor effects of CAFs in iCCA have been increasingly recognized, more recent cell lineage tracing studies, advanced single-cell RNA sequencing, and expanded biomarker analyses have provided new awareness into their ontogeny, as well as underscored their biological complexity as reflected by the presence of multiple subtypes. In addition, evidence supports CAFs' potential to display cancer-restrictive roles, including immunosuppression. However, CAFs also play important roles in facilitating metastasis, as exemplified by lymph node metastasis and peritoneal carcinomatosis, which are common in iCCA. Herein, the authors provide a timely appraisal of the origins and phenotypic and functional complexity of CAFs in iCCA, together with providing mechanistic insights into lymphangiogenesis and peritoneal metastasis relevant to this lethal human cancer.

Dual Targeting of Prostate-Specific Membrane Antigen and Fibroblast Activation Protein: Bridging Prostate Cancer Theranostics with Precision

Targeting Prostate Specific Membrane Antigen (PSMA) has proven highly useful and beneficial for prostate cancer (PCa) theranostics. However, patients with advanced metastatic castration-resistant prostate cancer (mCRPC) lack optimal PSMA expression resulting in poor specificity. To address this limitation, combination targeting is gaining popularity by synergistically boosting the theranostic efficacy. Herein, we thoroughly reviewed the most recent development of drug formulation for PCa theranostics by targeting both PSMA and Fibroblast Activation Protein (FAP). FAP is known to overexpress in cancer-associated fibroblasts (CAFs) within the tumor microenvironment (TME). It has been extensively studied as an effective target for the identification and treatment of a variety of cancer phenotypes. Along with the advantages and current updates on combination targeting of PSMA and FAP, this Review thoroughly discussed the expression patterns of PSMA and FAP in various cancer phenotypes, as well as their role in tumor growth, invasion, and metastasis, which is of great interest in the design and development of prostate cancer theranostics.

Gynecological cancer tumor Microenvironment: Unveiling cellular complexity and therapeutic potential

Gynecological cancers, including ovarian, cervical, endometrial, and vulvar cancers, present significant challenges in diagnosis and treatment globally. The tumor microenvironment (TME) plays a pivotal role in cancer progression and therapy response, necessitating a deeper understanding of its composition and dynamics. This review offers a comprehensive overview of the gynecological cancer tumor microenvironment, emphasizing its cellular complexity and therapeutic potential. The diverse cellular components of the TME, including cancer cells, immune cells, stromal cells, and extracellular matrix elements, are explored, elucidating their interplay in shaping tumor behavior and treatment outcomes. Across various stages of cancer progression, the TME exerts profound effects on tumor heterogeneity, immune modulation, angiogenesis, and metabolic reprogramming. The urgency for novel therapeutic strategies is underscored by understanding immune evasion mechanisms within the TME. Emerging approaches such as immunotherapy, stromal-targeting therapies, anti-angiogenic agents, and metabolic inhibitors are discussed, offering promising avenues for improving patient outcomes. Interdisciplinary collaborations and translational research are emphasized, aiming to advance precision oncology and enhance therapeutic efficacy in gynecological cancers.

MYC and KRAS cooperation: from historical challenges to therapeutic opportunities in cancer

RAS and MYC rank amongst the most commonly altered oncogenes in cancer, with RAS being the most frequently mutated and MYC the most amplified. The cooperative interplay between RAS and MYC constitutes a complex and multifaceted phenomenon, profoundly influencing tumor development. Together and individually, these two oncogenes regulate most, if not all, hallmarks of cancer, including cell death escape, replicative immortality, tumor-associated angiogenesis, cell invasion and metastasis, metabolic adaptation, and immune evasion. Due to their frequent alteration and role in tumorigenesis, MYC and RAS emerge as highly appealing targets in cancer therapy. However, due to their complex nature, both oncogenes have been long considered "undruggable" and, until recently, no drugs directly targeting them had reached the clinic. This review aims to shed light on their complex partnership, with special attention to their active collaboration in fostering an immunosuppressive milieu and driving immunotherapeutic resistance in cancer. Within this review, we also present an update on the different inhibitors targeting RAS and MYC currently undergoing clinical trials, along with their clinical outcomes and the different combination strategies being explored to overcome drug resistance. This recent clinical development suggests a paradigm shift in the long-standing belief of RAS and MYC "undruggability", hinting at a new era in their therapeutic targeting.

Insights into the Tumor Microenvironment-Components, Functions and Therapeutics

Similarly to our healthy organs, the tumor tissue also constitutes an ecosystem. This implies that stromal cells acquire an altered phenotype in tandem with tumor cells, thereby promoting tumor survival. Cancer cells are fueled by abnormal blood vessels, allowing them to develop and proliferate. Tumor-associated fibroblasts adapt their cytokine and chemokine production to the needs of tumor cells and alter the peritumoral stroma by generating more collagen, thereby stiffening the matrix; these processes promote epithelial-mesenchymal transition and tumor cell invasion. Chronic inflammation and the mobilization of pro-tumorigenic inflammatory cells further facilitate tumor expansion. All of these events can impede the effective administration of tumor treatment; so, the successful inhibition of tumorous matrix remodeling could further enhance the success of antitumor therapy. Over the last decade, significant progress has been made with the introduction of novel immunotherapy that targets the inhibitory mechanisms of T cell activation. However, extensive research is also being conducted on the stromal components and other cell types of the tumor microenvironment (TME) that may serve as potential therapeutic targets.

Cancer-Associated Fibroblast Heterogeneity and Its Influence on the Extracellular Matrix and the Tumor Microenvironment

The tumor microenvironment comprises multiple cell types, like cancer cells, endothelial cells, fibroblasts, and immune cells. In recent years, there have been massive research efforts focusing not only on cancer cells, but also on other cell types of the tumor microenvironment, thereby aiming to expand and determine novel treatment options. Fibroblasts represent a heterogenous cell family consisting of numerous subtypes, which can alter immune cell fractions, facilitate or inhibit tumor growth, build pre-metastatic niches, or stabilize vessels. These effects can be achieved through cell-cell interactions, which form the extracellular matrix, or via the secretion of cytokines or chemokines. The pro- or antitumorigenic fibroblast phenotypes show variability not only among different cancer entities, but also among intraindividual sites, including primary tumors or metastatic lesions. Commonly prescribed for arterial hypertension, the inhibitors of the renin-angiotensin system have recently been described as having an inhibitory effect on fibroblasts. This inhibition leads to modified immune cell fractions and increased tissue stiffness, thereby contributing to overcoming therapy resistance and ultimately inhibiting tumor growth. However, it is important to note that the inhibition of fibroblasts can also have the opposite effect, potentially resulting in increased tumor growth. We aim to summarize the latest state of research regarding fibroblast heterogeneity and its intricate impact on the tumor microenvironment and extracellular matrix. Specifically, we focus on highlighting recent advancements in the comprehension of intraindividual heterogeneity and therapy options within this context.

Molecular Targeted Therapies in Metastatic Prostate Cancer: Recent Advances and Future Challenges

Prostate cancer is the most frequent malignant tumor in men, and, despite the great improvements in survival in patients with localized cancer, the prognosis for metastatic disease remains poor. Novel molecular targeted therapies, which block specific molecules or signaling pathways in tumor cells or in their microenvironment, have shown encouraging results in metastatic castration-resistant prostate cancer. Among these therapeutic approaches, prostate-specific membrane antigen-targeted radionuclide therapies and DNA repair inhibitors represent the most promising ones, with some therapeutic protocols already approved by the FDA, whereas therapies targeting tumor neovascularization and immune checkpoint inhibitors have not yet demonstrated clear clinical benefits. In this review, the most relevant studies and clinical trials on this topic are illustrated and discussed, together with future research directions and challenges.

Exostosin 1 Knockdown Induces Chemoresistance in MV3 Melanoma Cells by Upregulating JNK and MEK/ERK Signaling

Heparan sulfate proteoglycans (HSPGs) possess various functions driving malignancy of tumors. However, their impact on tumor cell sensitivity to cytotoxic treatment is far less understood. Aiming to investigate this, we depleted HSPGs by downregulating Exostosin 1 (EXT1), a key enzyme in HS formation, or upregulating heparanase in human MV3 human melanoma cells, and investigated their response to cytotoxic drugs. Cytotoxicity of trametinib, doxorubicin, and mitoxantrone was detected by MTT assay. Insights into intracellular signaling was provided by kinome protein profiler array, and selected kinases were inhibited to investigate their impact on cell sensitization and migratory dynamics. EXT1 knockdown (EXT1kd) in MV3 cells affected the activity of doxorubicin and mitoxantrone, significantly increasing EC50 values two- or fourfold, respectively. Resistance formation was scarcely related to HSPG deficiency, suggested by enzymatic cleavage of HSPG in control cells. Notably, EXT1kd induced an upregulation of EGFR signaling via JNK and MEK/ERK, and hence blocking these kinases returned resistance to a sensitive level. JNK appeared as a key signal component, also inducing higher migratory activity of EXT1kd cells. Furthermore, EXT1kd upregulated thrombotic properties of MV3 cells, indicated by tissue factor and PAR-1 expression, functionally reflected by a stronger activation of platelet aggregation. EXT1 was confirmed to act as a tumor suppressor, shown here for the first time to affect chemosensitivity of melanoma cells.

Integrative analysis of WDR12 as a potential prognostic and immunological biomarker in multiple human tumors

Background: Mammalian WD-repeat protein 12 (WDR12), a family member of proteins containing repeats of tryptophan-aspartic acid (WD), is a potential homolog of yeast Ytm1p and consists of seven repeats of WD. Aim of the study: This study aims to investigate the potential oncogenic effects of WDR12 in various human malignancies throughout a pan-cancer analysis that has been carried out to examine the various patterns in which this gene is expressed and behaves in tumor tissues. Methods: Herein, we used The Cancer Genome Atlas (TCGA) and various computational tools to explore expression profiles, prognostic relevance, genetic mutations, immune cell infiltration, as well as the functional characteristics of WDR12 in multiple human cancers. Results: We found that WDR12 was inconsistently expressed in various cancers and that variations in WDR12 expression predicted survival consequences for cancer patients. Furthermore, we observed a significant correlation between WDR12 gene mutation levels and the prognosis of some tumors. Furthermore, significant correlations were found between WDR12 expression patterns and cancer-associated fibroblast (CAF) infiltration, myeloid-derived suppressor cells (MDSCs), tumor mutation burden, microsatellite instability and immunoregulators. Ultimately, pathway enrichment analysis revealed that WDR12-related pathways are involved in carcinogenesis. Conclusions: The findings of our study are stisfactory, demonstrating that WDR12 could serve as a promising reliable prognostic biomarker, as well as a therapeutic target for novel cancer therapeutic approaches.

Evolvability and emergence of tumor heterogeneity as a space-time function

The loss of control of cell proliferation, apoptosis regulation and contact inhibition leads to tumor development. While benign tumors are restricted to their primary space, i.e. where these tumors first originate, the metastatic tumors not only disseminate- facilitated by hypoxia-driven neovascularization- to distant secondary sites but also show substantial changes in metabolism, tissue architectures, gene expression profiles and immune phenotypes. All these alterations result in radio-, chemo- and immune-resistance rendering these metastatic tumor cells refractory to therapy. Since the beginning of the transformation, these factors- which influence each other- are incorporated to the developing and metastasizing tumor. As a result, the complexities in the heterogeneity of tumor progressively increase. This space-time function in the heterogeneity of tumors is generated by various conditions and factors at the genetic as well as microenvironmental levels, for example, endogenous retroviruses, methylation and epigenetic dysregulation that may be etiology-specific, cancer associated inflammation, remodeling of the extracellular matrix and mesenchymal cell shifted functions. On the one hand, these factors may cause de-differentiation of the tumor cells leading to cancer stem cells that contribute to radio-, chemo- and immune-resistance and recurrence of tumors. On the other hand, they may also enhance the heterogeneity under specific microenvironment-driven proliferation. In this editorial, we intend to underline the importance of heterogeneity in cancer progress, its evaluation and its use in correlation with the tumor evolution in a specific patient as a field of research for achieving precise patient-tailored treatments and amelioration of diagnostic (monitoring) tools and prognostic capacity.

Regulation of Extracellular Vesicle-Mediated Immune Responses against Antigen-Specific Presentation

Extracellular vesicles (EVs) produced by various immune cells, including B and T cells, macrophages, dendritic cells (DCs), natural killer (NK) cells, and mast cells, mediate intercellular communication and have attracted much attention owing to the novel delivery system of molecules in vivo. DCs are among the most active exosome-secreting cells of the immune system. EVs produced by cancer cells contain cancer antigens; therefore, the development of vaccine therapy that does not require the identification of cancer antigens using cancer-cell-derived EVs may have significant clinical implications. In this review, we summarise the molecular mechanisms underlying EV-based immune responses and their therapeutic effects on tumour vaccination.