A Subset of Cancer-Associated Fibroblasts Determines Therapy Resistance

Integrated single-cell RNA sequencing reveals the tumor heterogeneity and microenvironment landscape during liver metastasis in adenocarcinoma of esophagogastric junction

Background

Adenocarcinoma of the esophagogastric junction (AEGJ) is a highly aggressive tumor that frequently metastasizes to the liver. Understanding the cellular and molecular mechanisms that drive this process is essential for developing effective therapies.

Methods

We employed single-cell RNA sequencing to analyze the tumor heterogeneity and microenvironmental landscape in patients with AEGJ liver metastases. This approach enabled us to characterize the diverse cell populations involved in the liver metastatic process.

Results

Our analysis revealed a significant involvement of fibroblasts and mural cells in AEGJ liver metastasis. We identified a specific fibroblast type in AEGJ liver metastasis and observed distinct gene expression patterns between adenocarcinoma of the esophagogastric junction and other stomach adenocarcinomas. Our study demonstrated high expression of the SFRP2 gene in pericyte cells during the liver metastasis of AEGJ. The incorporation of GEO, TCGA, and immunofluorescence staining of SFRP2 expression enhanced our study. High expression of SFRP2 in pericytes may influence vascular stability and angiogenesis through the Wnt pathway.

Conclusion

Our study provides novel insights into the cellular interactions and molecular mechanisms that underlie AEGJ liver metastasis. Targeting the identified subtype of fibroblasts or influencing SFRP2 gene expression in pericytes may offer new therapeutic strategies for combating this aggressive tumor.

New insights into cancer pathology learned from the dynamics of cancer-associated fibroblasts

Paget's "Seed and Soil" theory, proposed in 1889, emphasizes the importance of the microenvironment where cancer cells grow in metastatic sites. Over a century later, this concept remains a cornerstone in comprehending cancer biology and devising treatment strategies. The "Seed and Soil" theory, which initially explained how cancer spreads to distant organs, now also applies to the tumor microenvironment (TME) within primary tumors. This theory emphasizes the critical interaction between cancer cells ("seeds") and their surrounding environment ("soil") and how this interaction affects both tumor progression within the primary site and at metastatic sites. An important point to note is that the characteristics of the TME are not static but dynamic, undergoing substantial changes during tumor progression and after treatment with therapeutic drugs. Cancer-associated fibroblasts (CAFs), recognized as the principal noncancerous cellular component within the TME, play multifaceted roles in tumor progression including promoting angiogenesis, remodeling the extracellular matrix, and regulating immune responses. In this comprehensive review, we focus on the findings regarding how the dynamics of CAFs contribute to cancer progression and drug sensitivity. Understanding the dynamics of CAFs could provide new insights into cancer pathology and lead to important advancements in cancer research and treatment.

A bibliometric analysis of drug resistance in immunotherapy for breast cancer: trends, themes, and research focus

While breast cancer treatments have advanced significantly nowadays, yet metastatic, especially triple-negative breast cancer (TNBC), remains challenging with low survival. Cancer immunotherapy, a promising approach for HER2-positive and TNBC, still faces resistance hurdles. Recently, numerous studies have set their sights on the resistance of immunotherapy for breast cancer. Our study provides a thorough comprehension of the current research landscape, hotspots, and emerging breakthroughs in this critical area through a meticulous bibliometric analysis. As of March 26, 2024, a total of 1341 articles on immunology resistance in breast cancer have been gathered from Web of Science Core Collection, including 765 articles and 576 reviews. Bibliometrix, CiteSpace and VOSviewer software were utilized to examine publications and citations per year, prolific countries, contributive institutions, high-level journals and scholars, as well as highly cited articles, references and keywords. The research of immunotherapy resistance in breast cancer has witnessed a remarkable surge over the past seven years. The United States and China have made significant contributions, with Harvard Medical School being the most prolific institution and actively engaging in collaborations. The most contributive author is Curigliano, G from the European Institute of Oncology in Italy, while Wucherpfennig, K. W. from the Dana-Farber Cancer Institute in the USA, had the highest citations. Journals highly productive primarily focus on clinical, immunology and oncology research. Common keywords include "resistance", "expression", "tumor microenvironment", "cancer", "T cell", "therapy", "chemotherapy" and "cell". Current research endeavors to unravel the mechanisms of immune resistance in breast cancer through the integration of bioinformatics, basic experiments, and clinical trials. Efforts are underway to develop strategies that improve the effectiveness of immunotherapy, including the exploration of combination therapies and advancements in drug delivery systems. Additionally, there is a strong focus on identifying novel biomarkers that can predict patient response to immunology. This study will provide researchers with an up-to-date overview of the present knowledge in drug resistance of immunology for breast cancer, serving as a valuable resource for informed decision-making and further research on innovative approaches to address immunotherapy resistance.

A review concerning the breast cancer-related tumour microenvironment

Breast cancer (BC) is currently the most common malignant tumour in women and one of the leading causes of their death around the world. New and increasingly personalised diagnostic and therapeutic tools have been introduced over the last few decades, along with significant advances regarding the study and knowledge related to BC. The tumour microenvironment (TME) refers to the tumour cell-associated cellular and molecular environment which can influence conditions affecting tumour development and progression. The TME is composed of immune cells, stromal cells, extracellular matrix (ECM) and signalling molecules secreted by these different cell types. Ever deeper understanding of TME composition changes during tumour development and progression will enable new and more innovative therapeutic strategies to become developed for targeting tumours during specific stages of its evolution. This review summarises the role of BC-related TME components and their influence on tumour progression and the development of resistance to therapy. In addition, an account on the modifications in BC-related TME components associated with therapy is given, and the completed or ongoing clinical trials related to this topic are presented.

Exploring the association of POSTN+ cancer-associated fibroblasts with triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis. Cancer-associated fibroblasts (CAFs) play a critical role in regulating TNBC tumor development. This study aimed to identify and characterize a specific subtype of CAFs associated with TNBC. Initially, using high-throughput bulk transcriptomic data in two cohorts, we identified three CAF-related subtypes (CS1, CS2, CS3) in TNBC samples. These three CAFs subtypes were closely linked to the tumor microenvironment. The CS1 subtype exhibited a relatively immune-rich microenvironment and a favourable prognosis, whereas the CS3 subtype displayed an immune-deprived tumor microenvironment and an unfavourable prognosis. Through WGCNA analysis, POSTN was identified as a key biomarker for CAFs associated with TNBC. Then, POSTN+CAFs was identified and characterized. Both POSTN and POSTN+CAFs showed significant positive correlations with stromal molecules HGF and MET at both the transcriptional and protein levels. Specifically co-localized with CAFs in the tumor stromal area, POSTN, produced by POSTN+CAFs, could modulate the HGF-MET axis, serving as a bypass activation pathway to regulate tumor cell proliferation in response to EGFR inhibitor and MET inhibitor. This study underscores the significance of POSTN and POSTN+CAFs as crucial targets for the diagnosis and treatment of TNBC.

Role of cancer-associated fibroblasts in colorectal cancer and their potential as therapeutic targets

Cancer-associated fibroblasts (CAFs) are mesenchymal cells in the tumor microenvironment (TME). CAFs are the most abundant cellular components in the TME of solid tumors. They affect the progression and course of chemotherapy and radiotherapy in various types of tumors including colorectal cancer (CRC). CAFs can promote tumor proliferation, invasion, and metastasis; protect tumor cells from immune surveillance; and resist tumor cell apoptosis caused by chemotherapy, resulting in drug resistance to chemotherapy. In recent years, researchers have become increasingly interested CAF functions and have conducted extensive research. However, compared to other types of malignancies, our understanding of the interaction between CRC cells and CAFs remains limited. Therefore, we searched the relevant literature published in the past 10 years, and reviewed the origin, biological characteristics, heterogeneity, role in the TME, and potential therapeutic targets of CAFs, to aid future research on CAFs and tumors.

Highly Mimetic Ex Vivo Lung-Cancer Spheroid-Based Physiological Model for Clinical Precision Therapeutics

Lung cancer remains a major health problem despite the considerable research into prevention and treatment methods. Through a deeper understanding of tumors, patient-specific ex vivo spheroid models with high specificity can be used to accurately investigate the cause, metastasis, and treatment strategies for lung cancer. Biofabricate lung tumors are presented, consisting of patient-derived tumor spheroids, endothelial cells, and lung decellularized extracellular matrix, which maintain a radial oxygen gradient, as well as biophysicochemical behaviors of the native tumors for precision medicine. It is also demonstrated that the developed lung-cancer spheroid model reproduces patient responses to chemotherapeutics and targeted therapy in a co-clinical trial, with 85% accuracy, 86.7% sensitivity, and 80% specificity. RNA sequencing analysis validates that the gene expression in the spheroids replicates that in the patient's primary tumor. This model can be used as an ex vivo predictive model for personalized cancer therapy and to improve the quality of clinical care.

The Diet as a Modulator of Tumor Microenvironment in Colorectal Cancer Patients

Colorectal cancer (CRC) is one of the most common cancers in Western countries and remains the second most common cause of cancer death worldwide. Many studies show the importance of diet and lifestyle in the incidence of CRC, as well as in CRC prevention. However, this review summarizes those studies that analyze the impact of nutrition on tumor microenvironment modulation and cancer progression. We review the available information about the effects of specific nutrients on cancer cell progression and on the different cells within the tumor microenvironment. Diet and nutritional status in the clinical management of colorectal cancer patients are also analyzed. Finally, future perspectives and challenges are discussed, with a view to improving CRC treatments by employing nutritional approaches. These promise great benefits and will eventually improve CRC patients' survival.

The Tumor Microenvironment in Tumorigenesis and Therapy Resistance Revisited

Tumorigenesis is a complex and dynamic process involving cell-cell and cell-extracellular matrix (ECM) interactions that allow tumor cell growth, drug resistance and metastasis. This review provides an updated summary of the role played by the tumor microenvironment (TME) components and hypoxia in tumorigenesis, and highlight various ways through which tumor cells reprogram normal cells into phenotypes that are pro-tumorigenic, including cancer associated- fibroblasts, -macrophages and -endothelial cells. Tumor cells secrete numerous factors leading to the transformation of a previously anti-tumorigenic environment into a pro-tumorigenic environment. Once formed, solid tumors continue to interact with various stromal cells, including local and infiltrating fibroblasts, macrophages, mesenchymal stem cells, endothelial cells, pericytes, and secreted factors and the ECM within the tumor microenvironment (TME). The TME is key to tumorigenesis, drug response and treatment outcome. Importantly, stromal cells and secreted factors can initially be anti-tumorigenic, but over time promote tumorigenesis and induce therapy resistance. To counter hypoxia, increased angiogenesis leads to the formation of new vascular networks in order to actively promote and sustain tumor growth via the supply of oxygen and nutrients, whilst removing metabolic waste. Angiogenic vascular network formation aid in tumor cell metastatic dissemination. Successful tumor treatment and novel drug development require the identification and therapeutic targeting of pro-tumorigenic components of the TME including cancer-associated- fibroblasts (CAFs) and -macrophages (CAMs), hypoxia, blocking ECM-receptor interactions, in addition to the targeting of tumor cells. The reprogramming of stromal cells and the immune response to be anti-tumorigenic is key to therapeutic success. Lastly, this review highlights potential TME- and hypoxia-centered therapies under investigation.

An integrated map of fibroblastic populations in human colon mucosa and cancer tissues

Fibroblasts and myofibroblasts are major mesenchymal cells in the lamina propria of colon mucosa and in colon cancer tissues. Detailed insight into the highly specific populations of fibroblasts and myofibroblasts is required to understand the integrity and homeostasis of human colon mucosa and colon cancer. Based on gene expression profiles of single cells, we identified fibroblast populations that produce extracellular matrix components, Wnt ligand- and BMP-secreting fibroblasts, chemokine- and chemokine ligand-generating fibroblasts, highly activated fibroblasts, immune-modulating fibroblasts, epithelial cell-modulating myofibroblasts, stimuli-responsive myofibroblasts, proliferating myofibroblasts, fibroblast-like myofibroblasts, matrix producing myofibroblasts, and contractile myofibroblasts in human colon mucosa. In colon cancer tissue, the compositions of fibroblasts and myofibroblasts were highly altered, as were the expressing patterns of genes including BMPs, Wnt ligands, chemokines, chemokine ligands, growth factors and extracellular matrix components in fibroblasts and myofibroblasts. Our work expands the working atlas of fibroblasts and myofibroblasts and provides a framework for interrogating the complexity of stromal cells in human healthy colon mucosa and colon cancer tissues.

CD16+ fibroblasts foster a trastuzumab-refractory microenvironment that is reversed by VAV2 inhibition

The leukocyte Fcγ receptor (FcγR)-mediated response is important for the efficacy of therapeutic antibodies; however, little is known about the role of FcγRs in other cell types. Here we identify a subset of fibroblasts in human breast cancer that express CD16 (FcγRIII). An abundance of these cells in HER2⁺ breast cancer patients is associated with poor prognosis and response to trastuzumab. Functionally, upon trastuzumab stimulation, CD16⁺ fibroblasts reduce drug delivery by enhancing extracellular matrix stiffness. Interaction between trastuzumab and CD16 activates the intracellular SYK-VAV2-RhoA-ROCK-MLC2-MRTF-A pathway, leading to elevated contractile force and matrix production. Targeting of a Rho family guanine nucleotide exchange factor, VAV2, which is indispensable for the function of CD16 in fibroblasts rather than leukocytes, reverses desmoplasia provoked by CD16⁺ fibroblasts. Collectively, our study reveals a role for the fibroblast FcγR in drug resistance, and suggests that VAV2 is an attractive target to augment the effects of antibody treatments.

Tumor-produced and aging-associated oncometabolite methylmalonic acid promotes cancer-associated fibroblast activation to drive metastatic progression

The systemic metabolic shifts that occur during aging and the local metabolic alterations of a tumor, its stroma and their communication cooperate to establish a unique tumor microenvironment (TME) fostering cancer progression. Here, we show that methylmalonic acid (MMA), an aging-increased oncometabolite also produced by aggressive cancer cells, activates fibroblasts in the TME, which reciprocally secrete IL-6 loaded extracellular vesicles (EVs) that drive cancer progression, drug resistance and metastasis. The cancer-associated fibroblast (CAF)-released EV cargo is modified as a result of reactive oxygen species (ROS) generation and activation of the canonical and noncanonical TGFβ signaling pathways. EV-associated IL-6 functions as a stroma-tumor messenger, activating the JAK/STAT3 and TGFβ signaling pathways in tumor cells and promoting pro-aggressive behaviors. Our findings define the role of MMA in CAF activation to drive metastatic reprogramming, unveiling potential therapeutic avenues to target MMA at the nexus of aging, the tumor microenvironment and metastasis.

Identification of Prognostic Markers and Potential Therapeutic Targets in Gastric Adenocarcinoma by Machine Learning Based on mRNAsi Index

Background

Cancer stem cells (CSCs), characterized by self-renewal and therapeutic resistance, play important roles in stomach adenocarcinoma (STAD). However, the molecular mechanism of STAD stem cells is still unclear. In this study, our purpose is to explore the expression of stem cell-related genes in STAD.

Methods

The stemness index based on mRNA expression (mRNAsi) was used to analyze STAD cases in The Cancer Genome Atlas (TCGA). Firstly, mRNAsi was used and analyzed by differential expression, survival analysis, clinical stage, and gender in STAD. Then, weighted gene coexpression network analysis (WGCNA) was used to discover the fascinating modules and key genes. Enrichment analysis was carried out to annotate the functions and pathways of key genes. The gene expression comprehensive database (GEO) in STAD was used to verify the expression levels of key genes in all cancers. Protein-protein interaction networks is used to determine the relationships between key genes.

Results

The mRNAsi was obviously upregulated in tumor cases. With the increase of tumor stage and T stage, the mRNAsi score decreased, and the overall survival rate of high score group patients was better. According to the degree of association with mRNAsi, different modules and key genes were screened out. A total of 6,740 differential genes were found, of which 1,147 genes were downregulated and 5,593 genes were upregulated. 19 key genes (BUB1, BUB1B, KIF14, NCAPH, RACGAP, KIF15, CENPF, TPX2, RAD54L, KIF18B, KIF4A, TTK, SGO2, PLK4, ARHGAP11A, XRCC2, Clorf112, NCAPG, and ORC6) were screened due to significant upregulation in STAD. And they had been proven that enriched from the cell cycle Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, relating to cell proliferation Gene Ontology (GO) terms, as well. Among them, 9 genes have been extensively associated to OS, and 3 genes had been associated to receive chemotherapy resistance. PPI protein network suggests that there is a sturdy correlation between these key genes.

Conclusion

A total of 19 key genes were found to play an essential position in retaining the traits of STAD stem cells. These genes can be used to evaluate the prognosis of STAD patients or become specific therapeutic targets.

Anti-Extra Domain B Splice Variant of Fibronectin Antibody-Drug Conjugate Eliminates Tumors with Enhanced Efficacy When Combined with Checkpoint Blockade

Extra domain B splice variant of fibronectin (EDB+FN) is an extracellular matrix protein (ECM) deposited by tumor-associated fibroblasts, and is associated with tumor growth, angiogenesis, and invasion. We hypothesized that EDB+FN is a safe and abundant target for therapeutic intervention with an antibody-drug conjugate (ADC). We describe the generation, pharmacology, mechanism of action, and safety profile of an ADC specific for EDB+FN (EDB-ADC). EDB+FN is broadly expressed in the stroma of pancreatic, non-small cell lung (NSCLC), breast, ovarian, head and neck cancers, whereas restricted in normal tissues. In patient-derived xenograft (PDX), cell-line xenograft (CLX), and mouse syngeneic tumor models, EDB-ADC, conjugated to auristatin Aur0101 through site-specific technology, demonstrated potent antitumor growth inhibition. Increased phospho-histone H3, a pharmacodynamic biomarker of response, was observed in tumor cells distal to the target site of tumor ECM after EDB-ADC treatment. EDB-ADC potentiated infiltration of immune cells, including CD3+ T lymphocytes into the tumor, providing rationale for the combination of EDB-ADC with immune checkpoint therapy. EDB-ADC and anti-PD-L1 combination in a syngeneic breast tumor model led to enhanced antitumor activity with sustained tumor regressions. In nonclinical safety studies in nonhuman primates, EDB-ADC had a well-tolerated safety profile without signs of either on-target toxicity or the off-target effects typically observed with ADCs that are conjugated through conventional conjugation methods. These data highlight the potential for EDB-ADC to specifically target the tumor microenvironment, provide robust therapeutic benefits against multiple tumor types, and enhance activity antitumor in combination with checkpoint blockade.

Cancer-Associated Fibroblasts Promote Tumor Aggressiveness in Head and Neck Cancer through Chemokine Ligand 11 and C-C Motif Chemokine Receptor 3 Signaling Circuit

Simple Summary

Certain tumor aggressiveness-associated mediators from cancer-associated fibroblasts (CAFs) in tumor microenvironment have been reported. Using gene expression analysis, we identified that CAFs overexpress Chemokine ligand 11 (CCL11), which is associated with tumor migration and invasion, increased expression of cancer stem cell properties, and induction of the epithelial-to-mesenchymal transition. Neutralization of CAF-induced CCL11 reversed the aggressive phenotype of cancer cells. Based on the immunohistochemical staining of clinical samples, we found that increased co-expression of CCL11 and its receptor, C-C Motif Chemokine Receptor 3 (CCR3), was associated with poor overall survival. Our results suggest that targeting CCL11-CCR3 signaling is a potential therapeutic strategy for patients with aggressive head and neck cancer.

Abstract

The tumor microenvironment (TME) plays a crucial role in tumor progression. One of its key stromal components, cancer-associated fibroblasts (CAFs), may crosstalk with cancer cells by secreting certain cytokines or chemokines. However, which important mediator(s) are released by CAFs, and the underlying molecular mechanism, remain largely unknown. In the present study, we isolated patient-derived CAFs and normal fibroblasts (NFs). Using microarray analysis, we detected chemokine ligand 11 (CCL11) overexpression in CAFs compared to NFs. CCL11 administration promoted the migration and invasion of head and neck cancer (HNC) cells with enhanced cancer stem cell-like properties and induction of epithelial-to-mesenchymal transition. Furthermore, neutralization of CCL11 activity reversed the aggressive phenotype of CAF-induced cancer cells. Confocal microscopy showed colocalization of CCL11 and CC chemokine receptor 3 (CCR3) on HNC cells. Moreover, immunohistochemical analysis of clinical samples from 104 patients with HNC showed that expression of CCL11 and CCR3 were significantly correlated with poor overall survival (p = 0.003 and 0.044, respectively). Collectively, CCL11 expressed on CAFs promotes HNC invasiveness, and neutralization of CCL11 reverses this effect. We propose that the CCL11/CCR3 signaling circuit is a potential target for optimizing therapeutic strategies against HNC.

Identification of key genes and pathways related to cancer-associated fibroblasts in chemoresistance of ovarian cancer cells based on GEO and TCGA databases

Background

Studies have revealed the implications of cancer-associated fibroblasts (CAFs) in tumor progression, metastasis, and treatment resistance. Here, in silico analyses were performed to reveal the key genes and pathways by which CAFs affected chemoresistance in ovarian cancer.

Methods

Candidate genes were obtained from the intersected differentially expressed genes in ovarian cancer, ovarian cancer chemoresistance, and ovarian CAF-related microarrays and chemoresistance-related genes from GeneCards databases. Kyoto Encyclopedia of Genes and Genomes enrichment analysis and Gene Set Enrichment Analysis were employed to identify the pathways engaged in ovarian cancer chemoresistance and ovarian CAF-related pathways. The top genes with high Degree in the protein-protein interaction network were intersected with the top genes enriched in the key pathways, followed by correlation analyses between key genes and chemotherapeutic response. The expression profiles of key genes were obtained from Human Protein Atlas database and TCGA-ovarian cancer data.

Results

p53, cell cycle, PI3K-Akt, and MAPK pathways were the key pathways related to the implication of CAFs in ovarian cancer chemoresistance. 276 candidate genes differentially expressed in CAFs were associated with ovarian cancer chemoresistance. MYC, IGF1, HRAS, CCND1, AKT1, RAC1, KDR, FGF2, FAS, and EGFR were enriched in the key chemoresistance-related ways. Furthermore, MYC, EGFR, CCND1 exhibited close association with chemotherapeutic response to platinum and showed a high expression in ovarian cancer tissues and platinum-resistant ovarian cancer cells.

Conclusion

The study suggests the key genes (MYC, EGFR, and CCND1) and pathways (p53, cell cycle, PI3K-Akt, and MAPK) responsible for the effect of CAFs on ovarian cancer chemoresistance.

Cancer-associated fibroblasts in breast cancer: Challenges and opportunities

The tumor microenvironment is proposed to contribute substantially to the progression of cancers, including breast cancer. Cancer-associated fibroblasts (CAFs) are the most abundant components of the tumor microenvironment. Studies have revealed that CAFs in breast cancer originate from several types of cells and promote breast cancer malignancy by secreting factors, generating exosomes, releasing nutrients, reshaping the extracellular matrix, and suppressing the function of immune cells. CAFs are also becoming therapeutic targets for breast cancer due to their specific distribution in tumors and their unique biomarkers. Agents interrupting the effect of CAFs on surrounding cells have been developed and applied in clinical trials. Here, we reviewed studies examining the heterogeneity of CAFs in breast cancer and expression patterns of CAF markers in different subtypes of breast cancer. We hope that summarizing CAF-related studies from a historical perspective will help to accelerate the development of CAF-targeted therapeutic strategies for breast cancer.

Tumor bud-derived CCL5 recruits fibroblasts and promotes colorectal cancer progression via CCR5-SLC25A24 signaling

Background

Tumor budding is included in the routine diagnosis of colorectal cancer (CRC) and is considered a tumor prognostic factor independent of TNM staging. This study aimed to identify the fibroblast-mediated effect of tumor bud-derived C–C chemokine ligand 5 (CCL5) on the tumor microenvironment (TME).

Methods

Recruitment assays and a human cytokine array were used to detect the main cytokines that CRC tumor buds secrete to recruit fibroblasts. siRNA transfection and inhibitor treatment were used to investigate the role of fibroblast CCL5 receptors in fibroblast recruitment. Subsequently, transcriptome sequencing was performed to explore the molecular changes occurring in fibroblasts upon stimulation with CCL5. Finally, clinical specimens and orthotopic xenograft mouse models were studied to explore the contribution of CCL5 to angiogenesis and collagen synthesis.

Results

Hematoxylin–eosin staining and immunochemistry revealed a higher number of fibroblasts at the invasive front of CRC tissue showing tumor budding than at sites without tumor budding. In vitro experiments demonstrated that CCL5 derived from tumor buds could recruit fibroblasts by acting on the CCR5 receptors on fibroblasts. Tumor bud-derived CCL5 could also positively regulate solute carrier family 25 member 24 (SLC25A24) expression in fibroblasts, potentially activating pAkt-pmTOR signaling. Moreover, CCL5 could increase the number of α-SMA^high CD90^high FAP^low fibroblasts and thus promote tumor angiogenesis by enhancing VEGFA expression and making fibroblasts transdifferentiate into vascular endothelial cells. Finally, the results also showed that CCL5 could promote collagen synthesis through fibroblasts, thus contributing to tumor progression.

Conclusions

At the invasive front of CRC, tumor bud-derived CCL5 can recruit fibroblasts via CCR5-SLC25A24 signaling, further promoting angiogenesis and collagen synthesis via recruited fibroblasts, and eventually create a tumor-promoting microenvironment. Therefore, CCL5 may serve as a potential diagnostic marker and therapeutic target for tumor budding in CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02300-w.

Sulfonylurea receptor 1-expressing cancer cells induce cancer-associated fibroblasts to promote non-small cell lung cancer progression

Cancer-associated fibroblasts (CAFs) play a pivotal role in cancer progression; however, how CAFs are induced remains elusive. Sulfonylurea receptor 1 (SUR1) is a tumor-enhancer in non-small cell lung carcinoma (NSCLC). Here, we probed the influence of SUR1-expressing cancer cells on CAFs. Results showed that high SUR1 expression positively correlated with α-SMA positive staining of CAFs in tumor tissues and poor prognosis of NSCLC patients. SUR1 contributed to normal fibroblast (NF) transformation into CAFs and facilitated the growth and metastasis of NSCLC in vivo. Conditioned medium (CM) and exosomes from SUR1-expressing cancer cells induced CAFs and promoted fibroblast migration. In cancer cells, SUR1 promoted p70S6K-induced KH-type splicing regulatory protein (KHSRP) phosphorylation at S395 to inhibit the binding of KHSRP with let-7a precursor (pre-let-7a) and decreasing mature let-7a-5p expression in cancer cells and exosomes. Let-7a-5p delivered by exosomes blocked NF transformation into CAFs by targeting TGFBR1 to inactivate the TGF-β signaling pathway. Glibenclamide, which targets SUR1, restrained CAFs and suppressed tumor growth in patient-derived xenograft models. Furthermore, we found that let-7a-5p was decreased in the tissues and plasma exosomes of NSCLC patients. In summary, SUR1-expressing cancer cells induce NF transformation into CAFs in the tumor microenvironment and promote NSCLC progression by transferring less exosomal let-7a-5p. Glibenclamide is a promising anti-cancer drug, and plasma exosomal let-7a-5p level is a potential diagnostic biomarker for NSCLC patients. These findings provide new therapeutic strategies by targeting SUR1 in NSCLC.

Cancer-associated fibroblasts and the tumor microenvironment in non-small cell lung cancer

INTRODUCTION

Non-small cell lung cancer (NSCLC) has a markedly poor prognosis as it progresses, and the prognosis is still unsatisfactory even with modern treatments. Cancer is composed of not only cancer cells, but also stroma consisting of various cell types. Cancer-associated fibroblasts (CAFs) are a major component of the stroma and the associated tumor microenvironment (TME). Particularly, CAFs are a critical component in elucidating the biological mechanisms of cancer progression and new therapeutic targets. This article outlines the TME formed by CAFs in NSCLC.

AREAS COVERED

Focusing on the TME in NSCLC, we discuss the mechanisms by which CAFs are involved in cancer progression, drug resistance, and the development of therapies targeting CAFs.

EXPERT OPINION

In the TME, CAFs profoundly contribute to tumor progression by interacting with cancer cells through direct contact or paracrine cytokine signaling. CAFs also interact with various other stromal components to establish a tumor-promoting immunosuppressive microenvironment and remodel the extracellular matrix. Furthermore, these effects are closely associated with drug resistance. Further elucidation of the stromal microenvironment, including CAFs, could prove to be crucial in the treatment of NSCLC.

Prognostic Value of LHFPL Tetraspan Subfamily Member 6 (LHFPL6) in Gastric Cancer: A Study Based on Bioinformatics Analysis and Experimental Validation

Purpose

The identification of biomarkers and effective therapeutic targets for gastric cancer (GC), the most common cause of cancer-related deaths around the world, is currently a major focus in research. Here, we examined the utility of LHFPL6 as a prognostic biomarker and therapeutic target for GC.

Methods

We explored the clinical relevance, function, and molecular role of LHFPL6 in GC using the MethSurv, cBioPortal, TIMER, Gene Expression Profiling Interactive Analysis, ONCOMINE, MEXPRESS, and EWAS Atlas databases. The GSE118919, GSE29272, and GSE13861 datasets were used for differential expression analysis. Using The Cancer Genome Atlas, we developed a Cox regression model and assessed the clinical significance of LHFPLs. In addition, we used the “CIBERSORT” algorithm to make reliable immune infiltration estimations. Western blot and immunohistochemistry were used to examine protein expression. Cell migration and invasion were assessed using transwell experiments. THP-1-derived macrophages and GC cells were co-cultured in order to model tumor–macrophage interactions in vitro. The levels of CD206 and CD163 were measured using immunofluorescence assays. The results were visualized with the “ggplot2” and “circlize” packages.

Results

Our results showed that in GC, LHFPL6 overexpression was significantly associated with a poor prognosis. Our findings also suggested that LHFPL6 may be involved in the activation of the epithelial–mesenchymal transition. Furthermore, LHFPL6 expression showed a positive correlation with the abundance of M2 macrophages, which are potent immunosuppressors.

Conclusion

LHFPL6 could be a prognostic biomarker and therapeutic target for GC.

Metronomic Anti-Cancer Therapy: A Multimodal Therapy Governed by the Tumor Microenvironment

Simple Summary

Metronomic chemotherapy with different mechanisms of action against cancer cells and their microenvironment represents an exceptional holistic cancer treatment. Each type of tumor has its own characteristics, including each individual tumor in each patient. Understanding the complexity of the dynamic interactions that take place between tumor and stromal cells and the microenvironment in tumor progression and metastases, as well as the response of the host and the tumor itself to anticancer therapy, will allow therapeutic actions with long-lasting effects to be implemented using metronomic regimens. This study aims to highlight the complexity of cellular interactions in the tumor microenvironment and summarize some of the preclinical and clinical results that explain the multimodality of metronomic therapy, which, together with its low toxicity, supports an inhibitory effect on the primary tumor and metastases. We also highlight the possible use of nano-therapeutic agents as good partners for metronomic chemotherapy.

Abstract

The concept of cancer as a systemic disease, and the therapeutic implications of this, has gained special relevance. This concept encompasses the interactions between tumor and stromal cells and their microenvironment in the complex setting of primary tumors and metastases. These factors determine cellular co-evolution in time and space, contribute to tumor progression, and could counteract therapeutic effects. Additionally, cancer therapies can induce cellular and molecular responses in the tumor and host that allow them to escape therapy and promote tumor progression. In this study, we describe the vascular network, tumor-infiltrated immune cells, and cancer-associated fibroblasts as sources of heterogeneity and plasticity in the tumor microenvironment, and their influence on cancer progression. We also discuss tumor and host responses to the chemotherapy regimen, at the maximum tolerated dose, mainly targeting cancer cells, and a multimodal metronomic chemotherapy approach targeting both cancer cells and their microenvironment. In a combination therapy context, metronomic chemotherapy exhibits antimetastatic efficacy with low toxicity but is not exempt from resistance mechanisms. As such, a better understanding of the interactions between the components of the tumor microenvironment could improve the selection of drug combinations and schedules, as well as the use of nano-therapeutic agents against certain malignancies.

Cancer-Associated Fibroblast Functions as a Road-Block in Cancer Therapy

The journey of a normal resident fibroblast belonging to the tumor microenvironment (TME) from being a tumor pacifier to a tumor patron is fascinating. We introduce cancer-associated fibroblast (CAF) as a crucial component of the TME. Activated-CAF partners with tumor cells and all components of TME in an established solid tumor. We briefly overview the origin, activation, markers, and overall functions of CAF with a particular reference to how different functions of CAF in an established tumor are functionally connected to the development of resistance to cancer therapy in solid tumors. We interrogate the role of CAF in mediating resistance to different modes of therapies. Functional diversity of CAF in orchestrating treatment resistance in solid tumors portrays CAF as a common orchestrator of treatment resistance; a roadblock in cancer therapy.

Immunobiology of cancer-associated fibroblasts in the context of radiotherapy

Radiotherapy (RT) still represents a mainstay of treatment in clinical oncology. Traditionally, the effectiveness of radiotherapy has been attributed to the killing potential of ionizing radiation (IR) over malignant cells, however, it has become clear that therapeutic efficacy of RT also involves activation of innate and adaptive anti-tumor immune responses. Therapeutic irradiation of the tumor microenvironment (TME) provokes profound cellular and biological reconfigurations which ultimately may influence immune recognition. As one of the major constituents of the TME, cancer-associated fibroblasts (CAFs) play central roles in cancer development at all stages and are recognized contributors of tumor immune evasion. While some studies argue that RT affects CAFs negatively through growth arrest and impaired motility, others claim that exposure of fibroblasts to RT promotes their conversion into a more activated phenotype. Nevertheless, despite the well-described immunoregulatory functions assigned to CAFs, little is known about the interplay between CAFs and immune cells in the context of RT. In this review, we go over current literature on the effects of radiation on CAFs and the influence that CAFs have on radiotherapy outcomes, and we summarize present knowledge on the transformed cellular crosstalk between CAFs and immune cells after radiation.

The Extracellular Matrix in Pancreatic Cancer: Description of a Complex Network and Promising Therapeutic Options

The stroma is a relevant player in driving and supporting the progression of pancreatic ductal adenocarcinoma (PDAC), and a large body of evidence highlights its role in hindering the efficacy of current therapies. In fact, the dense extracellular matrix (ECM) characterizing this tumor acts as a natural physical barrier, impairing drug penetration. Consequently, all of the approaches combining stroma-targeting and anticancer therapy constitute an appealing option for improving drug penetration. Several strategies have been adopted in order to target the PDAC stroma, such as the depletion of ECM components and the targeting of cancer-associated fibroblasts (CAFs), which are responsible for the increased matrix deposition in cancer. Additionally, the leaky and collapsing blood vessels characterizing the tumor might be normalized, thus restoring blood perfusion and allowing drug penetration. Even though many stroma-targeting strategies have reported disappointing results in clinical trials, the ECM offers a wide range of potential therapeutic targets that are now being investigated. The dense ECM might be bypassed by implementing nanoparticle-based systems or by using mesenchymal stem cells as drug carriers. The present review aims to provide an overview of the principal mechanisms involved in the ECM remodeling and of new promising therapeutic strategies for PDAC.

Testicular Diffuse Large B-Cell Lymphoma-Clinical, Molecular, and Immunological Features

Simple Summary

Testicular diffuse large B-cell lymphoma (T-DLBCL) is a rare and aggressive lymphoma entity that mainly affects elderly men. It has a high relapse rate with especially the relapses of the central nervous system associating with dismal outcome. T-DLBCL has a unique biology with distinct genetic characteristics and clinical presentation, and the increasing knowledge on the tumor microenvironment of T-DLBCL highlights the significance of the host immunity and immune escape in this rare lymphoma, presenting in an immune-privileged site of the testis. This review provides an update on the latest progress made in T-DLBCL research and summarizes the clinical perspectives in T-DLBCL.

Abstract

Primary testicular lymphoma is a rare lymphoma entity, yet it is the most common testicular malignancy among elderly men. The majority of the cases represent non-germinal center B-cell-like (non-GCB) diffuse large B-cell lymphoma (DLBCL) with aggressive clinical behavior and a relatively high relapse rate. Due to the rareness of the disease, no randomized clinical trials have been conducted and the currently recognized standard of care is based on retrospective analyses and few phase II trials. During recent years, the tumor microenvironment (TME) and tumor-related immunity have been the focus of many tumor biology studies, and the emergence of targeted therapies and checkpoint inhibitors has significantly modulated the field of cancer therapies. Testicular DLBCL (T-DLBCL) is presented in an immune-privileged site of the testis, and the roles of NF-κB pathway signaling, 9p24.1 aberrations, and tumor-infiltrating immune cells, especially immune checkpoint expressing lymphocytes and macrophages, seem to be unique compared to other lymphoma entities. Preliminary data on the use of immune checkpoint inhibitors in the treatment of T-DLBCL are promising and more studies are ongoing.

Tumor microenvironment: a prospective target of natural alkaloids for cancer treatment

Malignant tumor has become one of the major diseases that seriously endangers human health. Numerous studies have demonstrated that tumor microenvironment (TME) is closely associated with patient prognosis. Tumor growth and progression are strongly dependent on its surrounding tumor microenvironment, because the optimal conditions originated from stromal elements are required for cancer cell proliferation, invasion, metastasis and drug resistance. The tumor microenvironment is an environment rich in immune/inflammatory cells and accompanied by a continuous, gradient of hypoxia and pH. Overcoming immunosuppressive environment and boosting anti-tumor immunity may be the key to the prevention and treatment of cancer. Most traditional Chinese medicine have been proved to have good anti-tumor activity, and they have the advantages of better therapeutic effect and few side effects in the treatment of malignant tumors. An increasing number of studies are giving evidence that alkaloids extracted from traditional Chinese medicine possess a significant anticancer efficiency via regulating a variety of tumor-related genes, pathways and other mechanisms. This paper reviews the anti-tumor effect of alkaloids targeting tumor microenvironment, and further reveals its anti-tumor mechanism through the effects of alkaloids on different components in tumor microenvironment.

Cancer-Associated Fibroblast Heterogeneity: A Factor That Cannot Be Ignored in Immune Microenvironment Remodeling

Cancer-associated fibroblasts (CAFs) are important, highly heterogeneous components of the tumor extracellular matrix that have different origins and express a diverse set of biomarkers. Different subtypes of CAFs participate in the immune regulation of the tumor microenvironment (TME). In addition to their role in supporting stromal cells, CAFs have multiple immunosuppressive functions, via membrane and secretory patterns, against anti-tumor immunity. The inhibition of CAFs function and anti-TME therapy targeting CAFs provides new adjuvant means for immunotherapy. In this review, we outline the emerging understanding of CAFs with a particular emphasis on their origin and heterogeneity, different mechanisms of their regulation, as well as their direct or indirect effect on immune cells that leads to immunosuppression.

Architecture of Cancer-Associated Fibroblasts in Tumor Microenvironment: Mapping Their Origins, Heterogeneity, and Role in Cancer Therapy Resistance

The tumor stroma, a key component of the tumor microenvironment (TME), is a key determinant of response and resistance to cancer treatment. The stromal cells, extracellular matrix (ECM), and blood vessels influence cancer cell response to therapy and play key roles in tumor relapse and therapeutic outcomes. Of the stromal cells present in the TME, much attention has been given to cancer-associated fibroblasts (CAFs) as they are the most abundant and important in cancer initiation, progression, and therapy resistance. Besides releasing several factors, CAFs also synthesize the ECM, a key component of the tumor stroma. In this expert review, we examine the role of CAFs in the regulation of tumor cell behavior and reveal how CAF-derived factors and signaling influence tumor cell heterogeneity and development of novel strategies to combat cancer. Importantly, CAFs display both phenotypic and functional heterogeneity, with significant ramifications on CAF-directed therapies. Principal anti-cancer therapies targeting CAFs take the form of: (1) CAFs' ablation through use of immunotherapies, (2) re-education of CAFs to normalize the cells, (3) cellular therapies involving CAFs delivering drugs such as oncolytic adenoviruses, and (4) stromal depletion via targeting the ECM and its related signaling. The CAFs' heterogeneity could be a result of different cellular origins and the cancer-specific tumor microenvironmental effects, underscoring the need for further multiomics and biochemical studies on CAFs and the subsets. Lastly, we present recent advances in therapeutic targeting of CAFs and the success of such endeavors or their lack thereof. We recommend that to advance global public health and personalized medicine, treatments in the oncology clinic should be combinatorial in nature, strategically targeting both cancer cells and stromal cells, and their interactions.

Role of CD8+ T lymphocyte cells: Interplay with stromal cells in tumor microenvironment

CD8+ T lymphocytes are pivotal cells in the host response to antitumor immunity. Tumor-driven microenvironments provide the conditions necessary for regulating infiltrating CD8+ T cells in favor of tumor survival, including weakening CD8+ T cell activation, driving tumor cells to impair immune attack, and recruiting other cells to reprogram the immune milieu. Also in tumor microenvironment, stromal cells exert immunosuppressive skills to avoid CD8+ T cell cytotoxicity. In this review, we explore the universal function and fate decision of infiltrated CD8+ T cells and highlight their antitumor response within various stromal architectures in the process of confronting neoantigen-specific tumor cells. Thus, this review provides a foundation for the development of antitumor therapy based on CD8+ T lymphocyte manipulation.

Simultaneously targeting cancer-associated fibroblasts and angiogenic vessel as a treatment for TNBC

Fibrotic tumor stroma plays an important role in facilitating triple-negative breast cancer (TNBC) progression and chemotherapeutic resistance. We previously reported a rationally designed protein (ProAgio) that targets integrin αvβ3 at a novel site. ProAgio induces apoptosis via the integrin. Cancer-associated fibroblasts (CAFs) and angiogenic endothelial cells (aECs) in TNBC tumor express high levels of integrin αvβ3. ProAgio effectively induces apoptosis in CAFs and aECs. The depletion of CAFs by ProAgio reduces intratumoral collagen and decreases growth factors released from CAFs in the tumor, resulting in decreased cancer cell proliferation and apoptotic resistance. ProAgio also eliminates leaky tumor angiogenic vessels, which consequently reduces tumor hypoxia and improves drug delivery. The depletion of CAFs and reduction in hypoxia by ProAgio decreases lysyl oxidase (LOX) secretion, which may play a role in the reduction of metastasis. ProAgio stand-alone or in combination with a chemotherapeutic agent provides survival benefit in TNBC murine models, highlighting the therapeutic potential of ProAgio as a treatment strategy.

Tumor microenvironment promotes breast cancer chemoresistance

Breast cancer is presently the most predominant tumor type and the second leading cause of tumor-related deaths among women. Although advancements in diagnosis and therapeutics have momentously improved, chemoresistance remains an important challenge. Tumors oppose chemotherapeutic agents through a variety of mechanisms, with studies revealing that the tumor microenvironment (TME) is central to this process. The components of TME including stromal cells, immune cells, and non-stromal factors on exposure to chemotherapy promote the acquisition of resistant phenotype. Consequently, limited targeting of tumor cells leads to tumor recurrence after chemotherapy. Here, in this article, we summarize how TME alters chemotherapy responses in breast cancer. Furthermore, the role of different stromal cells viz., CAFs, TAMs, MSCs, endothelial cells, and cancer stem cells (CSC) in breast cancer chemoresistance is discussed in greater detail.

Differential Gemcitabine Sensitivity in Primary Human Pancreatic Cancer Cells and Paired Stellate Cells Is Driven by Heterogenous Drug Uptake and Processing

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC, also known as pancreatic cancer) is one of the deadliest tumor types, characterized by poor prognosis, profound chemoresistance and overall low survival. Gemcitabine remains the standard of care for all stages of PDAC, however, with poor clinical benefits which is considered to be due to reduced drug availability in tumor cells. Gemcitabine-induced cytotoxicity depends upon sufficient drug uptake followed by intracellular activation. Pancreatic stellate cells (PSCs), a major stromal component of PDAC, were recently reported to scavenge active metabolites of gemcitabine, thereby making it unavailable for cancer cells. Gemcitabine uptake and processing in both tumor cells and PSCs, as well as expression analysis of its molecular metabolic regulators, was investigated in this study. We observed heterogeneous gemcitabine-induced cytotoxicity in different pancreatic cancer cells whereas it was absent in PSCs. The gemcitabine-induced cytotoxicity in pancreatic cancer cells was driven by differential expression of its molecular regulators.

Abstract

Gemcitabine resistance in pancreatic ductal adenocarcinoma (PDAC) is attributed to cancer cell-intrinsic drug processing and the impact of the tumor microenvironment, especially pancreatic stellate cells (PSCs). This study uses human PDAC-derived paired primary cancer cells (PCCs) and PSCs from four different tumors, and the PDAC cell lines BxPC-3, Mia PaCa-2, and Panc-1, to assess the fate of gemcitabine by measuring its cellular uptake, cytotoxicity, and LC-MS/MS-based metabolite analysis. Expression analysis and siRNA-mediated knockdown of key regulators of gemcitabine (hENT1, CDA, DCK, NT5C1A) was performed. Compared to PSCs, both the paired primary PCCs and cancer cell lines showed gemcitabine-induced dose-dependent cytotoxicity, high uptake, as well as high and variable intracellular levels of gemcitabine metabolites. PSCs were gemcitabine-resistant and demonstrated significantly lower drug uptake, which was not influenced by co-culturing with their paired PCCs. Expression of key gemcitabine regulators was variable, but overall strong in the cancer cells and significantly lower or undetectable in PSCs. In cancer cells, hENT1 inhibition significantly downregulated gemcitabine uptake and cytotoxicity, whereas DCK knockdown reduced cytotoxicity. In conclusion, heterogeneity in gemcitabine processing among different pancreatic cancer cells and stellate cells results from the differential expression of molecular regulators which determines the effect of gemcitabine.

Addressing the tumour microenvironment in early drug discovery: a strategy to overcome drug resistance and identify novel targets for cancer therapy

The tumour microenvironment (TME) comprises not only malignant and non-malignant cells, but also the extracellular matrix (ECM), secreted factors, and regulators of cellular functions. In addition to genetic alterations, changes of the biochemical/biophysical properties or cellular composition of the TME have been implicated in drug resistance. Here, we review the composition of the ECM and different elements of the TME contributing to drug resistance, including soluble factors, hypoxia, extracellular acidity, and cell adhesion properties. We discuss selected approaches for modelling the TME, current progress, and their use in low-and high-throughput assays for preclinical studies. Lastly, we summarise the status quo of advanced 3D cancer models compatible with high-throughput screening (HTS), the technical practicalities and challenges.

The landscape of long non-coding RNAs in tumor stroma

AIMS

Long non-coding RNAs (lncRNAs) are associated with cancer development, while their relationship with the cancer-associated stromal components remains poorly understood. In this review, we performed a broad description of the functional landscape of stroma-associated lncRNAs in various cancers and their roles in regulating the tumor-stroma crosstalk.

MATERIALS AND METHODS

We carried out a systematic literature review of PubMed, Scopus, Medline, Bentham, and EMBASE (Elsevier) databases by using the keywords "LncRNAs in cancer," "LncRNAs in tumor stroma," "stroma," "cancer-associated stroma," "stroma in the tumor microenvironment," "tumor-stroma crosstalk," "drug resistance of stroma," and "stroma in immunosuppression" till July 2020. We collected the latest articles addressing the biological functions of stroma-associated lncRNAs in cancer.

KEY FINDINGS

These articles reported that dysregulated stroma-associated lncRNAs play significant roles in modulating the tumor microenvironment (TME) by the regulation of tumor-stroma crosstalk, epithelial to mesenchymal transition (EMT), endothelial to mesenchymal transition (EndMT), extracellular matrix (ECM) turnover, and tumor immunity.

SIGNIFICANCE

The tumor stroma is a substantial portion of the TME, and the dysregulation of tumor stroma-associated lncRNAs significantly contributes to cancer initiation, progression, angiogenesis, immune evasion, metastasis, and drug resistance. Thus, stroma-associated lncRNAs could be potentially useful targets for cancer therapy.

Tumor-Associated Neutrophils Can Predict Lymph Node Metastasis in Early Gastric Cancer

The consensus of endoscopic therapy for early gastric cancer (EGC) mainly depends on its clinicopathological features. However, the roles of tumor-associated neutrophils (TANs) in EGC remain uncertain. Here, we explored its predictive role for lymph node metastasis (LNM) in EGC. Three hundred twenty-two patients who underwent radical gastrectomy for EGC were enrolled. Preoperative peripheral blood was used to analyze the neutrophil-to-lymphocyte ratio (NLR), and the different status of TANs was determined by hematoxylin-and-eosin staining (H&E) and immunohistochemistry (IHC). TANs, rather than NLR, were positively associated with tumor size, Lauren classification, lymphovascular invasion (LVI), and LNM. Univariate analysis revealed that TANs were associated with LNM as well as tumor size, depth of invasion, Lauren classification, histological classification, LVI, and perineural invasion. In addition to histological classification and LVI, TANs were found to be an independent risk factor for LNM in EGC (P = 0.013). Stratification analysis by depth of invasion showed LVI in SM1 tumor, and both LVI and TANs (P = 0.042) in SM2 tumor were independent risk factors for LNM. In conclusion, TANs in EGC can predict LNM, and TANs may help to estimate LNM precisely in addition to the current criteria.

Exosomal lncRNA UCA1 from cancer-associated fibroblasts enhances chemoresistance in vulvar squamous cell carcinoma cells

AIM

In the current work, we aimed to explore whether Cancer-associated fibroblasts (CAF) exosomes played crucial roles in vulvar squamous cell carcinoma (VSCC) chemoresistance via mediating long noncoding RNAs (lncRNA).

METHODS

The IC50 value and cell apoptosis were assessed by the Cell Counting-8 Kit (CCK-8) assay and flow cytometry, respectively. Western blot analysis was used for the measurement of protein levels. The levels of urothelial cancer-associated 1 (UCA1), miR-103a and WEE1 G2 checkpoint kinase (WEE1) mRNA were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The target relationships among miR-103a, UCA1 and WEE1 were confirmed by dual-luciferase reporter assays. Xenograft model mice were established to observe the impact of exosomal UCA1 on cisplatin (CDDP) resistance in vivo.

RESULTS

Our data indicated that CAF enhanced CDDP resistance of VSCC cells in vitro. Extracellular UCA1 was transferred by exosomes derived from CAF. Exosomal UCA1 derived from CAF conferred VSCC cell resistance to CDDP. Moreover, UCA1 functioned as a miR-103a sponge in VSCC cells. The promotion of exosomal UCA1 on VSCC cell resistance to CDDP was mediated by miR-103a. WEE1 was a direct target of miR-103a, and exosomal miR-103a from CAF weakened CDDP resistance of VSCC cells by WEE1. Furthermore, exosomal UCA1 regulated WEE1 expression through sponging miR-103a. Additionally, exosomal UCA1 enhanced tumor growth and CDDP resistance in vivo.

CONCLUSION

Our findings suggested exosomal UCA1 derived from CAF conferred VSCC cell resistance to CDDP in vitro and in vivo at least partly through the miR-103a/WEE1 axis, highlighting a novel therapeutic method for improving the clinical benefits of CDDP chemotherapy in VSCC patients.

Bone marrow mesenchymal stem cells in microenvironment transform into cancer-associated fibroblasts to promote the progression of B-cell acute lymphoblastic leukemia

Bone marrow microenvironment is essential for leukemia cells to survive and escape the killing effect of chemotherapeutics. Cancer-associated fibroblasts (CAFs) are the dominant stromal cells in tumor microenvironment (TME), but their role in B-cell acute lymphoblastic leukemia (B-ALL) remains unclear. Here, RT-PCR and Western blotting in bone marrow mononuclear cells revealed higher proportions of CAFs markers α-SMA and FAP in the newly diagnosed and relapsed B-ALL patients. In vitro experiments, bone marrow mesenchymal stem cells (BM-MSCs) acquired a CAFs phenotype after co-culture with leukemia cells, which produced high level of tumor-promoting growth factors and reduced the daunorubicin (DNR)-induced damage to B-ALL cells. As for its mechanism, CAFs activation was mediated by TGF-β up-regulation in the co-culture system, and TGF-β triggered MSCs conversion into CAFs relying on the SDF-1/CXCR4 pathway. Further LY2109761 and AMD3100 effectively decreased the activation of CAFs through inhibiting TGF-β receptor and CXCR4. Comparative experiments with MSCs and transformed CAFs prompted that CAFs had more obvious effect than MSCs on stimulating leukemia progression through accelerating leukemia cell migration and invasion. These results clarified the important role of CAFs in B-ALL progression and the possible mechanisms of CAFs activation in leukemia microenvironment, which might provide a theoretical basis for B-ALL patients to find more effective targeted therapies targeting the bone marrow microenvironment.

Identification of cancer stem cell characteristics in liver hepatocellular carcinoma by WGCNA analysis of transcriptome stemness index

Cancer stem cells (CSCs) are characterized by self-renewal and -differential potential as compared to common cancer cells and play an important role in the development and therapeutic resistance of liver hepatocellular carcinoma (LIHC). However, the specific pathogenesis of LIHC stem cells is still unclear, and the genes involved in the stemness of LIHC stem cells are currently unknown. In this study, we investigated novel biomarkers associated with LIHC and explored the expression characteristics of stem cell-related genes in LIHC. We found that mRNA expression-based stemness index (mRNAsi) was significantly overexpressed in liver cancer tissues. Further, mRNAsi expression in LIHC increased with the tumor pathological grade, with grade 4 tumors harboring the greatest stem cell features. Upon establishing mRNAsi scores based on mRNA expression of every gene, we found an association with poor overall survival in LIHC. Moreover, modules of interest were determined based on weighted gene co-expression network analysis (WGCNA) inclusion criteria, and three significant modules (red, green, and brown) and 21 key genes (DCN, ECM1, HAND2, PTGIS, SFRP1, SRPX, COLEC10, GRP182, ADAMTS7, CD200, CDH11, COL8A1, FAP, LZTS1, MAP1B, NAV1, NOTCH3, OLFML2A, PRR16, TMEM119, and VCAN) were identified. Functional analysis of these 21 genes demonstrated their enrichment in pathways involved in angiogenesis, negative regulation of DNA-binding transcription factor activity, apoptosis, and autophagy. Causal relationship with proteins indicated that the Wnt, Notch, and Hypoxia pathways are closely related to LIHC tumorigenesis. To our knowledge, this is the first report of a novel CSC biomarker, mRNAsi, to predict the prognosis of LIHC. Further, we identified 21 key genes through mRNA expression network analysis, which could be potential therapeutic targets to inhibit the stemness of cancer cells in LIHC.

Epithelial-to-mesenchymal transition is a prognostic marker for patient outcome in advanced stage HNSCC patients treated with chemoradiotherapy

BACKGROUND

The prognosis of patients with HPV-negative advanced stage head and neck squamous cell carcinoma (HNSCC) remains poor. No prognostic markers other than TNM staging are routinely used in clinic. Epithelial-to-mesenchymal transition (EMT) has been shown to be a strong prognostic factor in other cancer types. The purpose of this study was to determine the role of EMT in HPV-negative HNSCC outcomes.

METHODS

Pretreatment tumor material from patients of two cohorts, totalling 174 cisplatin-based chemoradiotherapy treated HPV-negative HNSCC patients, was RNA-sequenced. Seven different EMT gene expression signatures were used for EMT status classification and generation of HNSCC-specific EMT models using Random Forest machine learning.

RESULTS

Mesenchymal classification by all EMT signatures consistently enriched for poor prognosis patients in both cohorts of 98 and 76 patients. Uni- and multivariate analyses show important HR of 1.6-5.8, thereby revealing EMT's role in HNSCC outcome. Discordant classification by these signatures prompted the generation of an HNSCC-specific EMT profile based on the concordantly classified samples in the first cohort (cross-validation AUC > 0.98). The independent validation cohort confirmed the association of mesenchymal classification by the HNSCC-EMT model with poor overall survival (HR = 3.39, p < 0.005) and progression free survival (HR = 3.01, p < 0.005) in multivariate analysis with TNM. Analysis of an additional HNSCC cohort from PET-positive patients with metastatic disease prior to treatment further supports this relationship and reveals a strong link of EMT to the propensity to metastasize.

CONCLUSIONS

EMT in HPV-negative HNSCC co-defines patient outcome after chemoradiotherapy. The generated HNSCC-EMT prediction models can function as strong prognostic biomarkers.

Nanotechnology Promotes Genetic and Functional Modifications of Therapeutic T Cells Against Cancer

Growing experience with engineered chimeric antigen receptor (CAR)-T cells has revealed some of the challenges associated with developing patient-specific therapy. The promising clinical results obtained with CAR-T therapy nevertheless demonstrate the urgency of advancements to promote and expand its uses. There is indeed a need to devise novel methods to generate potent CARs, and to confer them and track their anti-tumor efficacy in CAR-T therapy. A potentially effective approach to improve the efficacy of CAR-T cell therapy would be to exploit the benefits of nanotechnology. This report highlights the current limitations of CAR-T immunotherapy and pinpoints potential opportunities and tremendous advantages of using nanotechnology to 1) introduce CAR transgene cassettes into primary T cells, 2) stimulate T cell expansion and persistence, 3) improve T cell trafficking, 4) stimulate the intrinsic T cell activity, 5) reprogram the immunosuppressive cellular and vascular microenvironments, and 6) monitor the therapeutic efficacy of CAR-T cell therapy. Therefore, genetic and functional modifications promoted by nanotechnology enable the generation of robust CAR-T cell therapy and offer precision treatments against cancer.

Ciprofloxacin promotes polarization of CD86+CD206‑ macrophages to suppress liver cancer

Gut microbiota can promote tumor development by producing toxic metabolites and inhibiting the function of immune cells. Previous studies have demonstrated that gut microbiota can reach the liver through the circulation and promote the occurrence of liver cancer. Ciprofloxacin, an effective broad‑spectrum antimicrobial agent, can promote cell apoptosis and regulate the function of immune cells. As an important part of the tumor microenvironment, macrophages play an important role in tumor regulation. The present study demonstrated that the treatment of macrophages with ciprofloxacin was able to promote the production of interleukin‑1β, tumor necrosis factor‑α and the polarization of CD86+CD206‑ macrophages, while inhibiting the polarization of CD86‑CD206+ macrophages. This transformation may help macrophages promote tumor cell apoptosis, inhibit tumor cell proliferation, reduce metastasis and downregulate the phosphoinositide 3‑kinase/AKT signaling pathway in liver cancer cell lines. In vivo experiments demonstrated that macrophages treated with ciprofloxacin inhibited the growth of subcutaneous implanted tumors in nude mice. In conclusion, the findings of the present study indicated that ciprofloxacin may inhibit liver cancer by upregulating the expression of CD86+CD206‑ macrophages. This study further revealed the biological mechanism underlying the potential value of ciprofloxacin in antitumor therapy and provided new targets for the treatment of liver cancer.

Cancer-associated fibroblasts-derived VCAM1 induced by H. pylori infection facilitates tumor invasion in gastric cancer

Cancer-associated fibroblasts (CAFs) play a major role in the progression of stomach cancer, but the related mechanisms are not fully understood. H. pylori infection is recognized as one of the strongest risk factors for gastric carcinoma, but its effects on CAFs remain unknown. We aimed to determine the causative relationship between H. pylori infection in fibroblasts and the promoted cancer pathogenesis and progression in gastric cancer. Primary CAFs and normal activated fibroblasts (NAFs) were generated from gastric cancer patients. Gene signature of H. pylori-infected human stomach fibroblasts was performed using the RNA-seq analysis. Spheroid cell invasion assay and zebrafish cell line-derived xenograft (zCDX) model were introduced to evaluate tumor invasion induced by CAFs. The molecule interactions were determined using the kinetic binding analysis with the Biolayer Interferometry (BLI). Clinical significance and relevance were also assessed using the database analyses. H. pylori infection activated stomach fibroblasts and caused multiple gene alterations, including vascular adhesion molecule 1 (VCAM1). H. pylori infection increased VCAM1 expression in CAFs in gastric carcinoma via activation of JAK/STAT1 signaling pathway, and VCAM1 levels were positively associated with tumor progression and dismal prognosis in stomach cancer patients. Furthermore, CAFs-derived VCAM1 molecularly interacted with integrin αvβ1/5 in gastric cancer cells facilitated tumor invasion in vitro and in vivo. Our results identify a novel mechanism underlying CAFs to promote tumor invasion during H. pylori infection. These studies facilitate us for a better understanding of the molecular process of gastric carcinoma progression, and provide the potential strategies for gastric cancer therapy.

Reversing microtubule-directed chemotherapeutic drug resistance by co-delivering α2β1 inhibitor and paclitaxel with nanoparticles in ovarian cancer

Previous reports indicated that integrins associated signals are tightly related to tumor progression. Here, we observed elevated expression of integrin α2β1 in tumor tissues from microtubule-directed chemotherapeutic drugs (MDCDs) resistant patients compared with the samples from chemosensitive patients. More importantly, we sorted the integrin α2β1⁺ tumor cells and found those cells revealed high MDCDs resistance, whereas MDCDs shows effective cytotoxicity to those integrin α2β1^- tumor cells in vitro and in vivo. Mechanistically, we demonstrated that integrin α2β1 could induce MDCDs resistance through the activation of the PI3K/AKT pathway. Applying MPEG-PLA to co-encapsulate the integrin α2β1 inhibitor E7820 and MDCDs could effectively reverse MDCDs resistance, resulting in enhanced anticancer effects while avoiding potential systemic toxicity in vitro and in vivo. In conclusion, the expression of integrin α2β1 contributes to MDCDs resistance, while applying E7820 combination treatment by MPEG-PLA nanoparticles could reverse the resistance.

Fibroblastic FAP promotes intrahepatic cholangiocarcinoma growth via MDSCs recruitment

Desmoplasia is a hallmark of intrahepatic cholangiocarcinoma (ICC), which constitutes a barrier to infiltration of lymphocyte, but not myeloid cells. Given that dense desmoplastic stroma has been reported to be a barrier to infiltration of lymphocyte, but not myeloid cells. We here investigated whether fibroblastic FAP influenced ICC progression via non-T cell-related immune mechanisms. We demonstrated fibroblastic FAP expression was critical for STAT3 activation and CCL2 production, and ICC-CAFs were the primary source of CCL2 in human ICC microenvironment by using ICC-Fbs from six ICC patients. Fibroblastic knockdown of FAP significantly impaired the ability of ICC-CAFs to promote ICC growth, MDSCs infiltration and angiogenesis, which was restored by adding exogenous CCL2. Furthermore, interestingly, the tumor-promoting effect of fibroblastic FAP is dependent on MDSCs via secretion of CCL2, as depletion of Gr-1⁺ cells reversed the restoring effects of exogenous CCL2 on tumor growth and angiogenesis. In vitro migration assay confirmed that exogenous CCL2 could rescue the impaired ability of ICC-Fbs to attract Gr-1⁺ cells caused by fibroblastic FAP knockdown. In contrast, fibroblastic FAP knockdown had no effect on ICC cell proliferation and apoptotic resistance. Depletion MDSCs by anti-Gr-1 monoclonal antibody in subcutaneous transplanted tumor model abrogated tumor promotion by ICC-CAFs suggested that the pro-tumor function of Fibroblastic FAP relied on MDSCs. Mechanical, flow cytometry and chamber migration assay were conducted to find Fibroblastic FAP was required by the ability of ICC-CAFs to promote MDSC migration directly. Moreover, fibroblastic FAP knockdown had no effect on cell proliferation and apoptotic resistance. Here, we revealed the T-cell independent mechanisms underlying the ICC-promoting effect of fibroblastic FAP by attracting MDSCs via CCL2, which was mainly attributed to the ability of FAP to attract MDSCs and suggests that specific targeting fibroblastic FAP may represent a promising therapeutic strategy against ICC.

Modulation of redox metabolism negates cancer-associated fibroblasts-induced treatment resistance in a heterotypic 3D culture platform of pancreatic cancer

The complex interplay between cancer cells and their microenvironment remains a major challenge in the design and optimization of treatment strategies for pancreatic ductal adenocarcinoma (PDAC). Recent investigations have demonstrated that mechanistically distinct combination therapies hold promise for treatment of PDAC, but effective clinical translation requires more accurate models that account for the abundant tumor-stroma and its influence on cancer growth, metabolism and treatment insensitivity. In this study, a modular 3D culture model that comprised PDAC cells and patient-derived cancer-associated fibroblasts (CAFs) was developed to assess the effects of PDAC-CAF interactions on treatment efficacies. Using newly-developed high-throughput imaging and image analysis tools, it was found that CAFs imparted a notable and statistically significant resistance to oxaliplatin chemotherapy and benzoporphyrin derivative-mediated photodynamic therapy, which associated with increased levels of basal oxidative metabolism. Increased treatment resistance and redox states were similarly observed in an orthotopic xenograft model of PDAC in which cancer cells and CAFs were co-implanted in mice. Combination therapies of oxaliplatin and PDT with the mitochondrial complex I inhibitor metformin overcame CAF-induced treatment resistance. The findings underscore that heterotypic microtumor culture models recapitulate metabolic alterations stemming from tumor-stroma interactions. The presented infrastructure can be adapted with disease-specific cell types and is compatible with patient-derived tissues to enable personalized screening and optimization of new metabolism-targeted treatment regimens for pancreatic cancer.

Berberine inhibits epithelial-mesenchymal transition and promotes apoptosis of tumour-associated fibroblast-induced colonic epithelial cells through regulation of TGF-β signalling

Tumour-associated fibroblasts (TAFs) mediate the differentiation of adjacent stromal cells. Berberine (BBR), a monomer of traditional Chinese herbs, exhibits a potent therapeutic effect against cancer. However, the effects of BBR on the differentiation of normal colonic epithelial cells induced by TAFs have not been determined. In the present study, we selected the TAF-like myofibroblast cell line CCD-18Co. CCD-18Co-derived conditioned medium (CM) and co-culture induced epithelial-mesenchymal transition (EMT) changes in colonic epithelial HCoEpiC cells with decreased E-cadherin and increased vimentin and α-SMA expression. In addition, CCD-18Co stimulated the expression of ZEB1 and Snail and promoted motility. We used LY364947, a TGF-β receptor kinase type I (TβRI) inhibitor, and BBR. Our results showed that LY364947 and BBR inhibited these phenomena. BBR decreased the expression of ZEB1 and Snail, and this effect was concentration dependent. BBR also downregulated the expression of TβRI, TβRII, Smad2/p-Smad2 and Smad3/p-Smad3. In addition, BBR induced apoptosis in EMT-like HCoEpiC cells in a concentration-dependent manner with upregulation of Bax and downregulation of Bcl-2. However, VX-702, an inhibitor of p38 MAPK, significantly suppressed the apoptosis rate. BBR promoted the expression of p38 MAPK and phosphorylated p38 MAPK. In conclusion, berberine inhibits EMT and promotes apoptosis in TAF-induced colonic epithelial cells through mediation of the Smad-dependent and SMAD-independent TGF-β signalling pathways.

Clinical update on head and neck cancer: molecular biology and ongoing challenges

Head and neck squamous cell carcinomas (HNSCCs) are an aggressive, genetically complex and difficult to treat group of cancers. In lieu of truly effective targeted therapies, surgery and radiotherapy represent the primary treatment options for most patients. But these treatments are associated with significant morbidity and a reduction in quality of life. Resistance to both radiotherapy and the only available targeted therapy, and subsequent relapse are common. Research has therefore focussed on identifying biomarkers to stratify patients into clinically meaningful groups and to develop more effective targeted therapies. However, as we are now discovering, the poor response to therapy and aggressive nature of HNSCCs is not only affected by the complex alterations in intracellular signalling pathways but is also heavily influenced by the behaviour of the extracellular microenvironment. The HNSCC tumour landscape is an environment permissive of these tumours' aggressive nature, fostered by the actions of the immune system, the response to tumour hypoxia and the influence of the microbiome. Solving these challenges now rests on expanding our knowledge of these areas, in parallel with a greater understanding of the molecular biology of HNSCC subtypes. This update aims to build on our earlier 2014 review by bringing up to date our understanding of the molecular biology of HNSCCs and provide insights into areas of ongoing research and perspectives for the future.

Identification of Biomarkers for Controlling Cancer Stem Cell Characteristics in Bladder Cancer by Network Analysis of Transcriptome Data Stemness Indices

Background: Stem cells characterized by self-renewal and therapeutic resistance play crucial roles in bladder cancer (BLCA). However, the genes modulating the maintenance and proliferation of BLCA stem cells are still unclear. In this study, we aimed to characterize the expression of stem cell-related genes in BLCA.

Methods: The mRNA expression-based stemness index (mRNAsi) of The Cancer Genome Atlas (TCGA) was evaluated and corrected by tumor purity. Corrected mRNAsi were further analyzed with regard to muscle-invasive bladder cancer molecular subtypes, survival analysis, pathological staging characteristics, and outcomes after primary treatment. Next, weighted gene co-expression network analysis was used to find modules of interest and key genes. Functional enrichment analysis was performed to functionally annotate the modules and key genes. The expression levels of key genes in all cancers were validated using Oncomine and Gene Expression Omnibus (GEO) database containing molecular subtypes in BLCA. Protein interaction networks were used to identify upstream genes, and the relationships between genes were analyzed at the protein and transcription levels.

Findings: mRNAsi was significantly upregulated in cancer tissues. Corrected mRNAsi in BLCA increased as tumor stage increased, with T3 having the highest stem cell characteristics. Lower corrected mRNAsi scores had better overall survival and treatment outcome. The modules of interest and key genes were determined based on topological overlap measurement clustering results and the inclusion criteria. For 13 key genes (AURKA, BUB1B, CDCA5, CDCA8, KIF11, KIF18B, KIF2C, KIFC1, KPNA2, NCAPG, NEK2, NUSAP1, and RACGAP1), enriched gene ontology terms related to cell proliferation (e.g., mitotic nuclear division, spindle, and microtubule binding) were determined. Their expression did not differ according to the pathological stages of BLCA, and these genes were clearly overexpressed in many types of cancers. In GEO database, the expression levels of 13 key genes were higher in basal subtype with the highest stem cell characteristics than in luminal and its subtypes. AURKB and PLK1 may be regulated upstream of other key genes, and the key genes were found to be strongly correlated with each other and with upstream genes.

Interpretation: The 13 key genes identified in this study were found to play important roles in the maintenance of BLCA stem cells. Controlling the upstream genes AURKB and PLK1 may have applications in the treatment of BLCA. These genes may act as therapeutic targets for inhibiting the stemness characteristics of BLCA.