Three subtypes of lung cancer fibroblasts define distinct therapeutic paradigms

Cytokine-driven positive feedback loop organizes fibroblast transformation and facilitates gastric cancer progression

BACKGROUND

Gastric cancer (GC) is a malignancy that belongs to one of the most common leading causes of cancer death. Cancer-associated fibroblasts (CAFs) promote the GC cells' malignant behavior. It is still unknown how GC converts normal fibroblasts (NFs) to CAFs.

METHODS

GC cells were co-cultured with NFs. Bioinformatics was used to analyze the genes and signaling pathways that were changed in fibroblast. RT-PCR, western blot, and Elisa assays were used to detect the expression of cytokines in fibroblast and condition medium. Western blot and immunofluorescence demonstrated activation of relevant pathways in CAFs-like cells. Transwell, scrape, colony formation, and CCK-8 assays were performed to reveal the feedback effect of CAFs-like cells on GC cells.

RESULTS

GC promoted the conversion of NFs to CAFs by secreting Interleukin 17A (IL-17). It included both morphological and molecular marker changes. This process was achieved by activating the nuclear factor-κB (NF-κB) pathway. On the other hand, CAFs cells could secrete C-X-C Motif Chemokine Ligand 8 (IL-8, IL-8), which promoted the malignant phenotype of GC cells. In this way, a feedback loop of mutual influence was constructed in the GC and tumor microenvironment (TME).

CONCLUSIONS

Our research proved a novel model of GC-educated NFs. GC-IL-17-fibroblast-IL-8-GC axis might be a potential pathway of the interaction between GC and TME.

In Vitro Effect of Δ9-Tetrahydrocannabinol and Cannabidiol on Cancer-Associated Fibroblasts Isolated from Lung Cancer

There is evidence that demonstrates the effect of cannabinoid agonists inhibiting relevant aspects in lung cancer, such as proliferation or epithelial-to-mesenchymal transition (EMT). Most of these studies are based on evidence observed in in vitro models developed on cancer cell lines. These studies do not consider the complexity of the tumor microenvironment (TME). One of the main components of the TME is cancer-associated fibroblasts (CAFs), cells that are relevant in the control of proliferation and metastasis in lung cancer. In this work, we evaluated the direct effects of two cannabinoid agonists, tetrahydrocannabinol (THC) and cannabidiol (CBD), used alone or in combination, on CAFs and non-tumor normal fibroblasts (NFs) isolated from adenocarcinoma or from healthy lung tissue from the same patients. We observed that these compounds decrease cell density in vitro and inhibit the increase in the relative expression of type 1 collagen (COL1A1) and fibroblast-specific protein 1 (FSP1) induced by transforming growth factor beta (TGFβ). On the other hand, we studied whether THC and CBD could modulate the interactions between CAFs or NFs and cancer cells. We conditioned the culture medium with stromal cells treated or not with THC and/or CBD and cultured A549 cells with them. We found that culture media conditioned with CAFs or NFs increased cell density, induced morphological changes consistent with EMT, inhibited cadherin-1 (CDH1) gene expression, and induced an increase in the relative expression of cadherin-2 (CDH2) and vimentin (VIM) genes in A549 cells. These changes were inhibited or decreased by THC and CBD administered alone or in combination. In another series of experiments, we conditioned culture media with A549 cells treated or not with THC and/or CBD, in the presence or absence of TGFβ. We observed that culture media conditioned with A549 in the presence of TGFβ induced an increase in the expression of COL1A1 and VIM, both in CAFs and in non-tumor NFs. Both THC and CBD ameliorated these effects. In summary, the results presented here reinforce the usefulness of cannabinoid agonists for the treatment of some relevant aspects of lung cancer pathology, and demonstrate in a novel way their possible effects on CAFs as a result of their relationship with cancer cells. Likewise, the results reinforce the usefulness of the combined use of THC and CBD, which has important advantages in relation to the possibility of using lower doses, thus minimizing the psychoactive effects of THC.

Detection of PD-L1-Expressing Myeloid Cell Clusters in the Hyaluronan-Enriched Stroma in Tumor Tissue and Tumor-Draining Lymph Nodes

Expression of the transmembrane protein PD-L1 is frequently upregulated in cancer. Because PD-L1-expressing cells can induce apoptosis or anergy of T lymphocytes through binding to the PD1 receptor, the PD-L1-mediated inhibition of activated PD1⁺ T cells is considered a major pathway for tumor immune escape. However, the mechanisms that regulate the expression of PD-L1 in the tumor microenvironment are not fully understood. Analysis of organotypic tumor tissue slice cultures, obtained from mice with implanted syngeneic tumors (MBT2 bladder tumors in C3H mice, Renca kidney, and CT26 colon tumors in BALB/c mice), as well as from patients with cancer, revealed that tumor-associated hyaluronan (HA) supports the development of immunosuppressive PD-L1⁺ macrophages. Using genetically modified tumor cells, we identified epithelial tumor cells and cancer-associated mesenchymal fibroblast-like cells as a major source of HA in the tumor microenvironment. These HA-producing tumor cells, and particularly the vimentin-positive fibroblast-like cells of bone marrow origin, directly interact with tumor-recruited myeloid cells to form large stromal congregates/clusters that are highly enriched for both HA and PD-L1. Furthermore, similar cell clusters composed of HA-producing fibroblast-like cells and PD-L1⁺ macrophages were detected in tumor-draining, but not in distant, lymph nodes. Collectively, our findings indicate that the formation of multiple large HA-enriched stromal clusters that support the development of PD-L1-expressing APCs in the tumor microenvironment and draining lymph nodes could contribute to the immune escape and resistance to immunotherapy in cancer.

MDSCs might be "Achilles heel" for eradicating CSCs

During tumor initiation and progression, the complicated role of immune cells in the tumor immune microenvironment remains a concern. Myeloid-derived suppressor cells (MDSCs) are a group of immune cells that originate from the bone marrow and have immunosuppressive potency in various diseases, including cancer. In recent years, the key role of cancer stemness has received increasing attention in cancer development and therapy. Several studies have demonstrated the important regulatory relationship between MDSCs and cancer stem cells (CSCs). However, there is still no clear understanding regarding the complex interacting regulation of tumor malignancy, and current research progress is limited. In this review, we summarize the complicated role of MDSCs in the modulation of cancer stemness, evaluate the mechanism of the relationship between CSCs and MDSCs, and discuss potential strategies for eradicating CSCs with respect to MDSCs.

Melanoma cells with diverse invasive potential differentially induce the activation of normal human fibroblasts

Background

The tumor microenvironment consists of stromal cells, extracellular matrix, and physicochemical properties (e.g., oxygenation, acidification). An important element of the tumor niche are cancer-associated fibroblasts (CAFs). They may constitute up to 80% of the tumor mass and share some features with myofibroblasts involved in the process of wound healing. CAFs can facilitate cancer progression. However, their interaction with melanoma cells is still poorly understood.

Methods

We obtained CAFs using conditioned media derived from primary and metastatic melanoma cells, and via co-culture with melanoma cells on Transwell inserts. Using 2D and 3D wound healing assays and Transwell invasion method we evaluated CAFs’ motile activities, while coverslips with FITC-labeled gelatin, gelatin zymography, and fluorescence-based activity assay were employed to determine the proteolytic activity of the examined cells. Western Blotting method was used for the identification of CAFs’ markers as well as estimation of the mediators of MMPs’ (matrix metalloproteinases) expression levels. Lastly, CAFs’ secretome was evaluated with cytokine and angiogenesis proteomic arrays, and lactate chemiluminescence-based assay.

Results

Acquired FAP-α/IL6-positive CAFs exhibited elevated motility expressed as increased migration and invasion ratio, as well as higher proteolytic activity (area of digestion, MMP2, MMP14). Furthermore, fibroblasts activated by melanoma cells showed upregulation of the MMPs’ expression mediators’ levels (pERK, p-p38, CD44, RUNX), enhanced secretion of lactate, several cytokines (IL8, IL6, CXCL1, CCL2, ICAM1), and proteins related to angiogenesis (GM-CSF, DPPIV, VEGFA, PIGF).

Conclusions

Observed changes in CAFs’ biology were mainly driven by highly aggressive melanoma cells (A375, WM9, Hs294T) compared to the less aggressive WM1341D cells and could promote melanoma invasion, as well as impact inflammation, angiogenesis, and acidification of the tumor niche. Interestingly, different approaches to CAFs acquisition seem to complement each other showing interactions between studied cells.

Patient-Derived Organoids of Colorectal Cancer: A Useful Tool for Personalized Medicine

Colorectal cancer is one of the most important malignancies worldwide, with high incidence and mortality rates. Several studies have been conducted using two-dimensional cultured cell lines; however, these cells do not represent a study model of patient tumors very well. In recent years, advancements in three-dimensional culture methods have facilitated the establishment of patient-derived organoids, which have become indispensable for molecular biology-related studies of colorectal cancer. Patient-derived organoids are useful in both basic science and clinical practice; they can help predict the sensitivity of patients with cancer to chemotherapy and radiotherapy and provide the right treatment to the right patient. Regarding precision medicine, combining gene panel testing and organoid-based screening can increase the effectiveness of medical care. In this study, we review the development of three-dimensional culture methods and present the most recent information on the clinical application of patient-derived organoids. Moreover, we discuss the problems and future prospects of organoid-based personalized medicine.

An allosteric inhibitor against the therapy-resistant mutant forms of EGFR in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) therapy using small-molecule tyrosine kinase inhibitors (TKIs) is initially efficacious in patients with EGFR-mutant lung cancer, although drug resistance eventually develops. Allosteric EGFR inhibitors, which bind to a different EGFR site than existing ATP-competitive EGFR TKIs, have been developed as a strategy to overcome therapy-resistant EGFR mutations. Here we identify and characterize JBJ-09-063, a mutant-selective allosteric EGFR inhibitor that is effective across EGFR TKI-sensitive and resistant models, including those with EGFR T790M and C797S mutations. We further uncover that EGFR homo- or heterodimerization with other ERBB family members, as well as the EGFR L747S mutation, confers resistance to JBJ-09-063, but not to ATP-competitive EGFR TKIs. Overall, our studies highlight the potential clinical utility of JBJ-09-063 as a single agent or in combination with EGFR TKIs to define more effective strategies to treat EGFR-mutant lung cancer.

Bête Noire of Chemotherapy and Targeted Therapy: CAF-Mediated Resistance

Simple Summary

Tumor cells struggle to survive following treatment. The struggle ends in either of two ways. The drug combination used for the treatment blocks the proliferation of tumor cells and initiates apoptosis of cells, which is a win for the patient, or tumor cells resist the effect of the drug combination used for the treatment and continue to evade the effect of anti-tumor drugs, which is a bête noire of therapy. Cancer-associated fibroblasts are the most abundant non-transformed element of the microenvironment in solid tumors. Tumor cells play a direct role in establishing the cancer-associated fibroblasts’ population in its microenvironment. Since cancer-associated fibroblasts are activated by tumor cells, cancer-associated fibroblasts show unconditional servitude to tumor cells in their effort to resist treatment. Thus, cancer-associated fibroblasts, as the critical or indispensable component of resistance to the treatment, are one of the most logical targets within tumors that eventually progress despite therapy. We evaluate the participatory role of cancer-associated fibroblasts in the development of drug resistance in solid tumors. In the future, we will establish the specific mode of action of cancer-associated fibroblasts in solid tumors, paving the way for cancer-associated-fibroblast-inclusive personalized therapy.

Abstract

In tumor cells’ struggle for survival following therapy, they resist treatment. Resistance to therapy is the outcome of well-planned, highly efficient adaptive strategies initiated and utilized by these transformed tumor cells. Cancer cells undergo several reprogramming events towards adapting this opportunistic behavior, leading them to gain specific survival advantages. The strategy involves changes within the transformed tumors cells as well as in their neighboring non-transformed extra-tumoral support system, the tumor microenvironment (TME). Cancer-Associated Fibroblasts (CAFs) are one of the components of the TME that is used by tumor cells to achieve resistance to therapy. CAFs are diverse in origin and are the most abundant non-transformed element of the microenvironment in solid tumors. Cells of an established tumor initially play a direct role in the establishment of the CAF population for its own microenvironment. Like their origin, CAFs are also diverse in their functions in catering to the pro-tumor microenvironment. Once instituted, CAFs interact in unison with both tumor cells and all other components of the TME towards the progression of the disease and the worst outcome. One of the many functions of CAFs in influencing the outcome of the disease is their participation in the development of resistance to treatment. CAFs resist therapy in solid tumors. A tumor–CAF relationship is initiated by tumor cells to exploit host stroma in favor of tumor progression. CAFs in concert with tumor cells and other components of the TME are abettors of resistance to treatment. Thus, this liaison between CAFs and tumor cells is a bête noire of therapy. Here, we portray a comprehensive picture of the modes and functions of CAFs in conjunction with their role in orchestrating the development of resistance to different chemotherapies and targeted therapies in solid tumors. We investigate the various functions of CAFs in various solid tumors in light of their dialogue with tumor cells and the two components of the TME, the immune component, and the vascular component. Acknowledgment of the irrefutable role of CAFs in the development of treatment resistance will impact our future strategies and ability to design improved therapies inclusive of CAFs. Finally, we discuss the future implications of this understanding from a therapeutic standpoint and in light of currently ongoing and completed CAF-based NIH clinical trials.

Chimeric antigen receptor T cell therapy: challenges and opportunities in lung cancer

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the paradigm in hematological malignancies treatment, driving an ever-expanding number of basic research and clinical trials of genetically engineering T cells to treat solid tumors. CAR T-cell therapies based on the antibodies targeting Mesothelin, CEA, EGFR, EGFR, MUC1, DLL3, and emerging novel targets provide promising efficacy for lung cancer patients. However, clinical application of CAR T-cell therapy against lung cancer remains limited on account of physical and immune barriers, antigen escape and heterogeneity, on-target off-tumor toxicity, and many other reasons. Understanding the evolution of CAR structure and the generalizable requirements for manufacturing CAR T cells as well as the interplay between lung tumor immunology and CAR T cells will improve clinical translation of this therapeutic modality in lung cancer. In this review, we systematically summarize the latest advances in CAR T-cell therapy in lung cancer, focusing on the CAR structure, target antigens, challenges, and corresponding new strategies.

Clinical Application Perspectives of Lung Cancers 3D Tumor Microenvironment Models for In Vitro Cultures

Despite the enormous progress and development of modern therapies, lung cancer remains one of the most common causes of death among men and women. The key element in the development of new anti-cancer drugs is proper planning of the preclinical research phase. The most adequate basic research exemplary for cancer study are 3D tumor microenvironment in vitro models, which allow us to avoid the use of animal models and ensure replicable culture condition. However, the question tormenting the scientist is how to choose the best tool for tumor microenvironment research, especially for extremely heterogenous lung cancer cases. In the presented review we are focused to explain the key factors of lung cancer biology, its microenvironment, and clinical gaps related to different therapies. The review summarized the most important strategies for in vitro culture models mimicking the tumor–tumor microenvironmental interaction, as well as all advantages and disadvantages were depicted. This knowledge could facilitate the right decision to designate proper pre-clinical in vitro study, based on available analytical tools and technical capabilities, to obtain more reliable and personalized results for faster introduction them into the future clinical trials.

Heterogeneity of CAFfeinated Tumors: Sweet Targeting Perspectives

The tumor microenvironment (TME) shows heterogeneity within a tumor. An important element of the TME is cancer-associated fibroblasts (CAF). In this issue of Cancer Research, Bouchard and colleagues investigate the heterogeneity of CAFs from spatially different zones of lung adenocarcinoma resection specimens. Multiomics analysis revealed changes in the O-glycoproteome, unique to CAFs from the tumor edge, an effect reinforced by contact with cancer cells. This O-glycoprotein signature offers unique targeting perspectives that reciprocally affect cancer cell epithelial-to-mesenchymal plasticity, a key mechanism of cancer progression. Deeper understanding of the cancer-stimulating and cancer-inhibiting role of CAF subtypes will facilitate the development of CAF-directed therapeutic approaches. See related article by Bouchard et al., p. 648.