Pulmonary Fibroblasts Induce Epithelial Mesenchymal Transition and Some Characteristics of Stem Cells in Non-Small Cell Lung Cancer

Cancer-Associated Fibroblasts as the "Architect" of the Lung Cancer Immune Microenvironment: Multidimensional Roles and Synergistic Regulation with Radiotherapy

Cancer-associated fibroblasts (CAFs), as the "architect" of the immune microenvironment in lung cancer, play a multidimensional role in tumor progression and immune regulation. In this review, we summarize the heterogeneity of the origin and the molecular phenotype of CAFs in lung cancer, and explore the complex interactions between CAFs and multiple components of the tumor microenvironment, including the regulatory relationships with innate immune cells (e.g., tumor-associated macrophages, tumor-associated neutrophils), adaptive immune cells (e.g., T cells), and extracellular matrix (ECM). CAFs significantly influence tumor progression and immunomodulation through the secretion of cytokines, remodeling of the ECM, and the regulation of immune cell function significantly affects the immune escape and treatment resistance of tumors. In addition, this review also deeply explored the synergistic regulatory relationship between CAF and radiotherapy, revealing the key role of CAF in radiotherapy-induced remodeling of the immune microenvironment, which provides a new perspective for optimizing the comprehensive treatment strategy of lung cancer. By comprehensively analyzing the multidimensional roles of CAF and its interaction with radiotherapy, this review aims to provide a theoretical basis for the precise regulation of the immune microenvironment and clinical treatment of lung cancer.

Tumor microenvironment of cancer stem cells: Perspectives on cancer stem cell targeting

There are few tumor cell subpopulations with stem cell characteristics in tumor tissue, defined as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs), which can reconstruct neoplasms with malignant biological behaviors such as invasiveness via self-renewal and unlimited generation. The microenvironment that CSCs depend on consists of various cellular components and corresponding medium components. Among these factors existing at a variety of levels and forms, cytokine networks and numerous signal pathways play an important role in signaling transduction. These factors promote or maintain cancer cell stemness, and participate in cancer recurrence, metastasis, and resistance. This review aims to summarize the recent molecular data concerning the multilayered relationship between CSCs and CSC-favorable microenvironments. We also discuss the therapeutic implications of targeting this synergistic interplay, hoping to give an insight into targeting cancer cell stemness for tumor therapy and prognosis.

Stroma modulation of radiation response in head and neck squamous cell carcinoma: Insights from zebrafish larvae xenografts

BACKGROUND

The tumour microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC) consists of different subtypes of cells that interact with the tumour or with each other. This study investigates the possibility of co-culturing HNSCC cells with different stroma cells in a zebrafish xenograft model, focusing on the effect of stroma cells on HNSCC growth and response to irradiation.

MATERIAL AND METHOD

HNSCC metastatic cell line HSC-3 was used along with five types of stroma cells: normal gingival fibroblasts (NOF), cancer associated fibroblasts (CAF), macrophages, CD4+ T cells, and human umbilical vein endothelial cells (HUVEC). The mixture of HSC-3 cells and each-stroma cell type-was injected into 2-day post-fertilization zebrafish embryos, and the effect of stroma cells on tumour growth was tested. The study also aimed to mimic the HNSCC tumour by injecting a mixture of HSC-3 cells, CAFs, macrophages, and HUVECs into zebrafish embryos and testing the effect of these stroma cells on the cancer cells' response to irradiation compared to HSC-3-only tumours.

RESULTS

CAFs had a significant inducement effect on tumour size, while HUVECs showed the opposite effect. The irradiated group of HSC-3-only tumour had a significantly smaller tumor cell area compared to the control, while the group with stroma cells and HSC-3 cells showed cancer cells being resistant to irradiation.

CONCLUSION

This is the first report of co-culturing cancer cells with several types of stroma cells using a zebrafish xenograft model. This study also highlighted the role of stroma cells in turning the cancer cells from radioresponsive to radioresistant.

Two new adenopeptins B and C inhibit sphere formation of pancreatic cancer cells

Cancer remains one of the leading causes of death worldwide, particularly pancreatic cancer being lethal because of its aggressiveness and lack of early detection methods. A factor that contributes to malignancy are cancer stem cell-like characteristics promoted by the tumor-stromal interaction. Given that fibroblast conditioned medium (CM) promotes sphere formation of cancer cells, a cancer stem cell-like characteristic, its inhibitor could be a new anticancer agent. By exploring microbial cultures as a source, we found new compounds, namely, adenopeptins B (1) and C (2), from Acremonium sp. ESF00140. 1 and 2 selectively and potently inhibited the sphere formation of pancreatic cancer cells cultured in the fibroblast CM compared with the control medium. Oxygen consumption rate (OCR) assays showed that 1 and 2 inhibit OCR in pancreatic cancer cells. Studies of similar compounds suggested mitochondrial complex V inhibition. Therefore, results of measuring the activity of human mitochondrial complex V revealed that 1 and 2 inhibited its activity. Oligomycin A, an inhibitor of mitochondrial complex V, as well as 1 and 2, strongly inhibited the sphere formation of pancreatic cancer cells cultured in fibroblast CM. The addition of 1 and 2 to pancreatic cancer cells cultured in fibroblast CM increased reactive oxygen species (ROS) production compared with that in the control medium. In pancreatic cancer cells cultured in fibroblast CM, mitochondria significantly influence sphere formation, and targeting their function with 1 and 2 might provide a new therapeutic approach for pancreatic cancer.

The Nexus of Inflammation-Induced Epithelial-Mesenchymal Transition and Lung Cancer Progression: A Roadmap to Pentacyclic Triterpenoid-Based Therapies

Lung cancer is the leading cause of cancer-related death worldwide. Its high mortality is partly due to chronic inflammation that accompanies the disease and stimulates cancer progression. In this review, we analyzed recent studies and highlighted the role of the epithelial-mesenchymal transition (EMT) as a link between inflammation and lung cancer. In the inflammatory tumor microenvironment (iTME), fibroblasts, macrophages, granulocytes, and lymphocytes produce inflammatory mediators, some of which can induce EMT. This leads to increased invasiveness of tumor cells and self-renewal of cancer stem cells (CSCs), which are associated with metastasis and tumor recurrence, respectively. Based on published data, we propose that inflammation-induced EMT may be a potential therapeutic target for the treatment of lung cancer. This prospect is partially realized in the development of EMT inhibitors based on pentacyclic triterpenoids (PTs), described in the second part of our study. PTs reduce the metastatic potential and stemness of tumor cells, making PTs promising candidates for lung cancer therapy. We emphasize that the high diversity of molecular mechanisms underlying inflammation-induced EMT far exceeds those that have been implicated in drug development. Therefore, analysis of information on the relationship between the iTME and EMT is of great interest and may provide ideas for novel treatment approaches for lung cancer.

Characterization of 3D NSCLC Cell Cultures with Fibroblasts or Macrophages for Tumor Microenvironment Studies and Chemotherapy Screening

The study of 3D cell culture has increased in recent years as a model that mimics the tumor microenvironment (TME), which is characterized by exhibiting cellular heterogeneity, allowing the modulation of different signaling pathways that enrich this microenvironment. The TME exhibits two main cell populations: cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAM). The aim of this study was to investigate 3D cell cultures of non-small cell lung cancer (NSCLC) alone and in combination with short-term cultured dermal fibroblasts (FDH) and with differentiated macrophages of the THP-1 cell line. Homotypic and heterotypic spheroids were morphologically characterized using light microscopy, immunofluorescence and transmission electron microscopy. Cell viability, cycle profiling and migration assay were performed, followed by the evaluation of the effects of some chemotherapeutic and potential compounds on homotypic and heterotypic spheroids. Both homotypic and heterotypic spheroids of NSCLC were generated with fibroblasts or macrophages. Heterotypic spheroids with fibroblast formed faster, while homotypic ones reached larger sizes. Different cell populations were identified based on spheroid zoning, and drug effects varied between spheroid types. Interestingly, heterotypic spheroids with fibroblasts showed similar responses to the treatment with different compounds, despite being smaller. Cellular viability analysis required multiple methods, since the responses varied depending on the spheroid type. Because of this, the complexity of the spheroid should be considered when analyzing compound effects. Overall, this study contributes to our understanding of the behavior and response of NSCLC cells in 3D microenvironments, providing valuable insights for future research and therapeutic development.

Possible cancer-causing capacity of COVID-19: Is SARS-CoV-2 an oncogenic agent?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown diverse life-threatening effects, most of which are considered short-term. In addition to its short-term effects, which has claimed many millions of lives since 2019, the long-term complications of this virus are still under investigation. Similar to many oncogenic viruses, it has been hypothesized that SARS-CoV-2 employs various strategies to cause cancer in different organs. These include leveraging the renin angiotensin system, altering tumor suppressing pathways by means of its nonstructural proteins, and triggering inflammatory cascades by enhancing cytokine production in the form of a "cytokine storm" paving the way for the emergence of cancer stem cells in target organs. Since infection with SARS-CoV-2 occurs in several organs either directly or indirectly, it is expected that cancer stem cells may develop in multiple organs. Thus, we have reviewed the impact of coronavirus disease 2019 (COVID-19) on the vulnerability and susceptibility of specific organs to cancer development. It is important to note that the cancer-related effects of SARS-CoV-2 proposed in this article are based on the ability of the virus and its proteins to cause cancer but that the long-term consequences of this infection will only be illustrated in the long run.

Integrative analyses of bulk and single-cell RNA-seq identified cancer-associated fibroblasts-related signature as a prognostic factor for immunotherapy in NSCLC

An emerging view regarding cancer-associated fibroblast (CAF) is that it plays a critical role in tumorigenesis and immunosuppression in the tumor microenvironment (TME), but the clinical significance and biological functions of CAFs in non-small cell lung cancer (NSCLC) are still poorly explored. Here, we aimed to identify the CAF-related signature for NSCLC through integrative analyses of bulk and single-cell genomics, transcriptomics, and proteomics profiling. Using CAF marker genes identified in weighted gene co-expression network analysis (WGCNA), we constructed and validated a CAF-based risk model that stratifies patients into two prognostic groups from four independent NSCLC cohorts. The high-score group exhibits a higher abundance of CAFs, decreased immune cell infiltration, increased epithelial-mesenchymal transition (EMT), activated transforming growth factor beta (TGFβ) signaling, and a limited survival rate compared with the low-score group. Considering the immunosuppressive feature in the high-score group, we speculated an inferior clinical response for immunotherapy in these patients, and this association was successfully verified in two NSCLC cohorts treated with immune checkpoint blockades (ICBs). Furthermore, single-cell RNA sequence datasets were used to clarify the molecular mechanisms underlying the aggressive and immunosuppressive phenotype in the high-score group. We found that one of the genes in the risk model, filamin binding LIM protein 1 (FBLIM1), is mainly expressed in fibroblasts and upregulated in CAFs compared to fibroblasts from normal tissue. FBLIM1-positive CAF subtype was correlated with increased TGFβ expression, higher mesenchymal marker level, and immunosuppressive tumor microenvironment. Finally, we demonstrated that FBLIM1 might serve as a poor prognostic marker for immunotherapy in clinical samples. In conclusion, we identified a novel CAF-based classifier with prognostic value in NSCLC patients and those treated with ICBs. Single-cell transcriptome profiling uncovered FBLIM1-positive CAFs as an aggressive subtype with a high abundance of TGFβ, EMT, and an immunosuppressive phenotype in NSCLC.

Fibroblasts as Turned Agents in Cancer Progression

Differentiated epithelial cells reside in the homeostatic microenvironment of the native organ stroma. The stroma supports their normal function, their G0 differentiated state, and their expansion/contraction through the various stages of the life cycle and physiologic functions of the host. When malignant transformation begins, the microenvironment tries to suppress and eliminate the transformed cells, while cancer cells, in turn, try to resist these suppressive efforts. The tumor microenvironment encompasses a large variety of cell types recruited by the tumor to perform different functions, among which fibroblasts are the most abundant. The dynamics of the mutual relationship change as the sides undertake an epic battle for control of the other. In the process, the cancer "wounds" the microenvironment through a variety of mechanisms and attracts distant mesenchymal stem cells to change their function from one attempting to suppress the cancer, to one that supports its growth, survival, and metastasis. Analogous reciprocal interactions occur as well between disseminated cancer cells and the metastatic microenvironment, where the microenvironment attempts to eliminate cancer cells or suppress their proliferation. However, the altered microenvironmental cells acquire novel characteristics that support malignant progression. Investigations have attempted to use these traits as targets of novel therapeutic approaches.

Therapeutic Targeting of Cancer-Associated Fibroblasts in the Non-Small Cell Lung Cancer Tumor Microenvironment

Lung cancer is the most frequently diagnosed cancer and the leading cause of cancer death worldwide. The most common lung cancer is non-small cell lung cancer (NSCLC), with an overall 5-year survival rate of around 20% because NSCLC is a metastatic disease. A better understanding of the mechanism underlying lung cancer metastasis is therefore urgently needed. The tumor microenvironment involves different types of stromal cells and functions as key components in the progression of NSCLC. Through epithelial-mesenchymal transition (EMT), in which epithelial cells lose their polarity and acquire mesenchymal potential, cancer cells acquire metastatic abilities, as well as cancer stem-cell-like potential. We previously reported that cancer-associated fibroblasts (CAFs) interact with lung cancer cells to allow for the acquisition of malignancy and treatment resistance by paracrine loops via EMT signals in the tumor microenvironment. Furthermore, CAFs regulate the cytotoxic activity of immune cells via various cytokines and chemokines, creating a microenvironment of immune tolerance. Regulation of CAFs can therefore affect immune responses. Recent research has shown several roles of CAFs in NSCLC tumorigenesis, owing to their heterogeneity, so molecular markers of CAFs should be elucidated to better classify tumor-promoting subtypes and facilitate the establishment of CAF-specific targeted therapies. CAF-targeted cancer treatments may suppress EMT and regulate the niche of cancer stem cells and the immunosuppressive network and thus may prove useful for NSCLC treatment through multiple mechanisms.

Human papillomavirus infection and lung adenocarcinoma: special benefit is observed in patients treated with immune checkpoint inhibitors

BACKGROUND

Human papilloma virus (HPV) has been associated with the development and modulation of response in a series of neoplasms. In the case of lung adenocarcinoma, its role in etiology and pathogenesis is still controversial. Considering that this infection brings foreign epitopes, it could be of prognostic significance in patients with lung adenocarcinoma treated with immunotherapy.

METHODS

In a retrospective cohort study we evaluated the presence of HPV genomic material in lung adenocarcinoma primary lesions with the INNO-LiPA platform. Viral replication was also evaluated by detecting the presence of oncoprotein E6/E7 messenger RNA (mRNA) by quantitative RT-PCR. To confirm possible hypotheses regarding viral oncogenesis, vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 (HIF1) were evaluated with stromal fibrosis and immunoscore.

RESULTS

A total of 133 patients were included in the analysis, of whom 34 tested positive for HPV, reaching an estimated prevalence of 25.6% [95% confidence interval (CI) 18.2% to 32.9%]. E6/7 mRNA was identified in 28 out of the 34 previously positive cases (82.3%). In immune checkpoint inhibitor (ICI)-treated patients, the median overall survival reached 22.3 months [95% CI 19.4 months- not reached (NR)] for HPV-negative and was not reached in HPV-positive (HPV+) ones (95% CI 27.7-NR; P = 0.008). With regard to progression-free survival, HPV- patients reached a median of 9.2 months (95% CI 7.9-11.2 months) compared to 14.3 months (95% CI 13.8-16.4 months) when HPV was positive (P = 0.001). The overall response rate for HPV+ patients yielded 82.4% compared to 47.1% in negative ones. No differences regarding programmed death-ligand 1, VEGF, HIF1, stromal fibrosis, or immunoscore were identified.

CONCLUSIONS

In patients with HPV+ lung adenocarcinoma, a significant benefit in overall response and survival outcomes is observed.

Collagen 3D matrices as a model for the study of cell behavior in pulmonary fibrosis

Purpose: Idiopathic pulmonary fibrosis (IPF) is a complex progressive chronic lung disease where epithelial to mesenchymal interaction, extracellular matrix (ECM) contact, and pro-fibrotic cytokines dynamics take part in the development of the disease. The study of IPF in the widespread in vitro two-dimensional (2 D) culture fails to explain the interaction of cells with the changing environment that occurs in fibrotic lung tissue. A three-dimensional (3 D) co-culture model might shed light on the pathogenesis of IPF by mimicking the fibrotic environment. Materials and Methods: Fibroblasts from nine IPF were isolated and embedded in collagen matrices with the alveolar epithelial human cell line (A549) on the top. Cells were also cultured in 2 D with and without TGF-β1 as a conventional model to compare with. Both types of cells were isolated separately. Protein and gene expression of the main fibrotic markers were measured by qPCR, Western blot, and ELISA. Results: IPF fibroblasts to myofibroblasts differentiation was observed in the 3 D model and in cells stimulated with TGF-β1. In addition, ECM-related genes were highly up-regulated in the 3 D collagen matrix. A549 co-cultured 3 D with IPF fibroblasts showed EMT activation, with down-regulation of E-cadherin (CDH1). However, other pro-fibrotic genes as VIM, TGFB1, and MMP7 were up-regulated in A549 co-cultured 3 D with fibroblasts. Conclusions: 3 D-collagen matrices might induce fibroblasts' fibrotic phenotype as in the classic TGF-β1 model, by up-regulating genes associated with matrix production. In addition, IPF lung fibroblasts seem to exert a pro-fibrotic influence in A549 cells when they are co-cultured. These results suggest that an improved 3 D co-culture model might serve as an important tool to study the fibrotic process and its regulation.

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.

Crotoxin Modulates Events Involved in Epithelial-Mesenchymal Transition in 3D Spheroid Model

Epithelial–mesenchymal transition (EMT) occurs in the early stages of embryonic development and plays a significant role in the migration and the differentiation of cells into various types of tissues of an organism. However, tumor cells, with altered form and function, use the EMT process to migrate and invade other tissues in the body. Several experimental (in vivo and in vitro) and clinical trial studies have shown the antitumor activity of crotoxin (CTX), a heterodimeric phospholipase A2 present in the Crotalus durissus terrificus venom. In this study, we show that CTX modulates the microenvironment of tumor cells. We have also evaluated the effect of CTX on the EMT process in the spheroid model. The invasion of type I collagen gels by heterospheroids (mix of MRC-5 and A549 cells constitutively prepared with 12.5 nM CTX), expression of EMT markers, and secretion of MMPs were analyzed. Western blotting analysis shows that CTX inhibits the expression of the mesenchymal markers, N-cadherin, α-SMA, and αv. This study provides evidence of CTX as a key modulator of the EMT process, and its antitumor action can be explored further for novel drug designing against metastatic cancer.

Epigenetic Reprogramming of Tumor-Associated Fibroblasts in Lung Cancer: Therapeutic Opportunities

Simple Summary

Lung cancer is the leading cause of cancer death among both men and women, partly due to limited therapy responses. New avenues of knowledge are indicating that lung cancer cells do not form a tumor in isolation but rather obtain essential support from their surrounding host tissue rich in altered fibroblasts. Notably, there is growing evidence that tumor progression and even the current limited responses to therapies could be prevented by rescuing the normal behavior of fibroblasts, which are critical housekeepers of normal tissue function. For this purpose, it is key to improve our understanding of the molecular mechanisms driving the pathologic alterations of fibroblasts in cancer. This work provides a comprehensive review of the main molecular mechanisms involved in fibroblast transformation based on epigenetic reprogramming, and summarizes emerging therapeutic approaches to prevent or overcome the pathologic effects of tumor-associated fibroblasts.

Abstract

Lung cancer is the leading cause of cancer-related death worldwide. The desmoplastic stroma of lung cancer and other solid tumors is rich in tumor-associated fibroblasts (TAFs) exhibiting an activated/myofibroblast-like phenotype. There is growing awareness that TAFs support key steps of tumor progression and are epigenetically reprogrammed compared to healthy fibroblasts. Although the mechanisms underlying such epigenetic reprogramming are incompletely understood, there is increasing evidence that they involve interactions with either cancer cells, pro-fibrotic cytokines such as TGF-β, the stiffening of the surrounding extracellular matrix, smoking cigarette particles and other environmental cues. These aberrant interactions elicit a global DNA hypomethylation and a selective transcriptional repression through hypermethylation of the TGF-β transcription factor SMAD3 in lung TAFs. Likewise, similar DNA methylation changes have been reported in TAFs from other cancer types, as well as histone core modifications and altered microRNA expression. In this review we summarize the evidence of the epigenetic reprogramming of TAFs, how this reprogramming contributes to the acquisition and maintenance of a tumor-promoting phenotype, and how it provides novel venues for therapeutic intervention, with a special focus on lung TAFs.

Tumor Microenvironment: Involved Factors and Signaling Pathways in Epithelial-Mesenchymal Transition

Context: Metastasis is a main cause of death in patients with cancer, whereby tumor cells withdraw from the primary site of the tumor mass and produce secondary tumor mass in new sites. Primary tumor cells depart collectively and individually to invade closed and distant sites. Evidence Acquisition: This review considers TME-derived factors that actuate signaling pathways to induce epithelial-mesenchymal transition (EMT). National Center for Biotechnology Information (NCBI) was the main resource. Google Scholar and Scopus were other databases for finding articles. Keywords that were inserted into the search box of databases to identify related articles were ‘metastasis’, ‘invasion’, ‘epithelial-mesenchymal transition’, ‘EMT’, ‘tumor microenvironment’, ‘TME’, ‘TME cells’, and ‘signaling pathway in EMT’. Titles and abstracts of the articles were studied to choose the right articles. Finally, 107 articles were selected to study in detail and use as references. Results: EMT is a type of metastasis that deprives epithelial single-cells of their characteristic features and acquires mesenchymal features facilitating the departure from the primary tumor mass. During EMT, cell-adhesion and apical-basal polarity rapture and cells obtain movement capability. The tumor microenvironment (TME) leads EMT through secretion factors and signaling pathways. As a result of activating these pathways, transcription factors that abolish epithelial gene expressions and augment mesenchymal gene expression are induced. Conclusions: In this review, recent research published in TME and EMT fields were highlighted and critically appraised. Effect of factors-derived TME cells on EMT were manifested that propose favorite targets for a therapeutic goal to inhibit metastasis. However, data about the effect of the combination of TME cells on metastasis have a small part in the literature.

[SP13786 Inhibits the Migration and Invasion of Lung Adenocarcinoma Cell A549 by Supressing Stat3-EMT via CAFs Exosomes]

BACKGROUND

Fibroblast activation protein (FAP) is one of the surface markers of cancer-associated fibroblasts (CAFs) and is closely related to the malignant characterization of CAFs. SP13786 is a specific micromolecule inhibitor of FAP and this study is to investigate the effects and mechanism of SP13786 on the migration and invasion of A549 cells through regulating exosomes of CAFs.

METHODS

CAFs and paracancerous fibroblasts (PTFs) were isolated and subcultured from freshly resected lung adenocarcinoma tissues and paracancerous normal tissues separately. MTT assay was used to detect the proliferation of CAFs incubated by different concentrations of SP13786; PTFs-exo, CAFs-exo and CAFs+SP13786-exo were extracted by polymer precipitation method. The A549 cells were divided into Ctrl group, PTFs group, CAFs group and SP13786 group and each group was incubated with DMEM, PTFs-exo, CAFs-exo and CAFs+SP13786-exo separately. Laser confocal microscope was used to observe the endocytoses of exosomes by A549 cells. The expression of alpha-smooth muscle actin (α-SMA) and FAP in PTFs and CAFs and the expression of E-cadherin, N-cadherin, Slug, Stat3 and P-Stat3 in A549 cells were detected by immunofluorescence, immunohistochemistry and Western blot. The migration and invasion ability of A549 cells were detected by cell scratch and transwell methods.

RESULTS

α-SMA and FAP were expressed much higher in CAFs than that in PTFs which indicate that CAFs and PTFs were successfully obtained from lung adenocarcinoma and paracancerous tissues (P<0.05). MTT showed that the 50% inhibitory concentration (IC50) of SP13786 for CAFs was about 3.3 nmol/L. In addition, SP13786 can significantly decrease the expression of α-SMA and FAP in CAFs which means that targeted inhibition of FAP could reduce the malignant characteristics of CAFs (P<0.05). Laser confocal microscope found that exosomes from CAFs could be taken up by A549 cells and scratch and transwell tests showed that the endocytosed CAFs-exo could promote the migration and invasion of A549 cells (P<0.001), while FAP inhibitor SP13786 could inhibit the effects of CAFs-exo on A549 cells (P<0.05). Furthermore, Immunofluorescence and Western blot showed that CAFs-exo could promote EMT by decreasing E-cadherin expression and increasing N-cadherin, Slug expression in A549 cells while FAP inhibitor SP13786 could significantly supress CAFs-exo-induced epithelial-mesenchymal transition (EMT) of A549 cells (P<0.05). Moreover, the expression of P-Stat3 was obviously increased in A549 cells of CAFs group and significantly down-regulated in SP13786 group (P<0.05) whereas there was no significant difference in total Stat3 between CAFs and SP13786 groups (P>0.05). Finally, WP1066 (a specific inhibitor of Stat3) was used to comfirm whether SP13786 could influence EMT of A549 cells by inhibiting Stat3 phosphorylation via CAFs-Exo. The results showed that when the phosphorylation of Stat3 in CAFs group was inhibited by WP1066, SP13786 could not influence the P-Stat3 expression and EMT of A549 cells anymore (P>0.05).

CONCLUSIONS

As a specific micromolecule inhibitor of FAP, SP13786 indirectly inhibits the migration and invasion of A549 cells by affecting exosomes of CAFs. The possible mechanism is to inhibit the phosphorylation of Stat3 and thus affect the EMT of A549 cells.

Extracellular Vesicle Mediated Tumor-Stromal Crosstalk Within an Engineered Lung Cancer Model

Tumor-stromal interactions within the tumor microenvironment (TME) influence lung cancer progression and response to therapeutic interventions, yet traditional in vitro studies fail to replicate the complexity of these interactions. Herein, we developed three-dimensional (3D) lung tumor models that mimic the human TME and demonstrate tumor-stromal crosstalk mediated by extracellular vesicles (EVs). EVs released by tumor cells, independent of p53 status, and fibroblasts within the TME mediate immunomodulatory effects; specifically, monocyte/macrophage polarization to a tumor-promoting M2 phenotype within this 3D-TME. Additionally, immune checkpoint inhibition in a 3D model that included T cells showed an inhibition of tumor growth and reduced hypoxia within the TME. Thus, perfused 3D tumor models incorporating diverse cell types provide novel insights into EV-mediated tumor-immune interactions and immune-modulation for existing and emerging cancer therapies.

The Newly Synthetized Chalcone L1 Is Involved in the Cell Growth Inhibition, Induction of Apoptosis and Suppression of Epithelial-to-Mesenchymal Transition of HeLa Cells

Over the past decades, natural products have emerged as promising agents with multiple biological activities. Many studies suggest the antioxidant, antiangiogenic, antiproliferative and anticancer effects of chalcones and their derivatives. Based on these findings, we decided to evaluate the effects of the newly synthetized chalcone L1 in a human cervical carcinoma cell (HeLa) model. Presented results were obtained by western blot and flow cytometric analyses, live cell imaging and antimigratory potential of L1 in HeLa cells was demonstrated by scratch assay. In the present study, we proved the role of L1 as an effective agent with antiproliferative activity supported by G2/M cell cycle arrest and apoptosis. Moreover, we proved that L1 is involved in modulating Transforming Growth Factor-β1 (TGF-β) signal transduction through Smad proteins and it also modulates other signalling pathways including Akt, JNK, p38 MAPK, and Erk1/2. The involvement of L1 in epithelial-to-mesenchymal transition was demonstrated by the regulation of N-cadherin, E-cadherin, and MMP-9 levels. Here, we also evaluated the effect of conditioned medium from BJ-5ta human foreskin fibroblasts in HeLa cell cultures with subsequent L1 treatment. Taken together, these data suggest the potential role of newly synthesized chalcone L1 as an anticancer-tumour microenvironment modulating agent.

Effects of pirfenidone targeting the tumor microenvironment and tumor-stroma interaction as a novel treatment for non-small cell lung cancer

Targeting cancer-associated fibroblasts (CAFs), as well as the crosstalk between stroma and cancer cells, could be of value in managing cancers. Pirfenidone (PFD) is an anti-fibrotic agent for idiopathic pulmonary fibrosis. This study aimed to investigate the possibility that PFD might exert an anti-tumor effect through inhibition of fibroblast activation and the tumor-stroma interaction in non-small cell lung cancer (NSCLC) cell lines in vitro and in vivo. PFD significantly inhibited myofibroblast differentiation and activation of both primary cultured normal human lung fibroblasts and CAFs. Cocultivation of NSCLC cells with conditioned media (CM) of fibroblasts changed the morphology or epithelial to mesenchymal transition (EMT) status, and PFD suppressed these changes. Cocultivation of CAFs with CM of NSCLC cells also induced activation of CAFs, and these changes were suppressed by PFD. On in vivo examination, CAFs promoted tumor progression, and PFD suppressed tumor progression with an inhibitory effect on tumor-stroma crosstalk. PFD might inhibit not only fibroblast activity, but also the crosstalk between cancer cells and fibroblasts. PFD may have great potential as a novel treatment for NSCLC from multiple perspectives.

β-Carotene exerts anti-colon cancer effects by regulating M2 macrophages and activated fibroblasts

The tumor microenvironment (TME), consisting of stromal fibroblasts, immune cells, cancer cells and other cell types, plays a crucial role in cancer progression and metastasis. M2 macrophages and activated fibroblasts (AFs) modulate behavior of cancer cells in the TME. Since nutritional effects on cancer progression, including colorectal cancer (CRC), may be mediated by alterations in the TME, we determined the ability of β-carotene (BC) to mediate anti-cancer effects through regulation of macrophage polarization and fibroblast activation in CRC. The M2 macrophage phenotype was induced by treating U937 cells with phorbol-12-myristate-13-acetate and interleukin (IL)-4. Treatment of these M2 macrophages with BC led to suppression of M2-type macrophage-associated markers and of the IL-6/STAT3 signaling pathway. In separate experiments, AFs were induced by treating CCD-18Co cells with transforming growth factor-β1. BC treatment suppressed expression of fibroblast activation markers. In addition, conditioned media from BC-treated M2 macrophages and AF inhibited cancer stem cell markers, colon cancer cell invasiveness and migration, and the epithelial-mesenchymal transition (EMT). In vivo, BC supplementation inhibited tumor formation and the expression of M2 macrophage markers in an azoxymethane/dextran sodium sulfate-induced colitis-associated CRC mouse model. To our knowledge, the present findings provide the first evidence suggesting that the potential therapeutic effects of BC on CRC are mediated by the inhibition of M2 macrophage polarization and fibroblast activation.

The prognostic impact of programmed cell death 1 and its ligand and the correlation with epithelial-mesenchymal transition in thymic carcinoma

Background

The significance of epithelial‐mesenchymal transition (EMT) and immune checkpoint proteins in thymic carcinoma remains unknown. We examined the clinical significance of EMT, tumor‐infiltrating lymphocytes expressing the immune checkpoint protein, programmed cell death 1 (PD‐1 + TILs), and the expression of PD‐1 ligand 1 (PD‐L1) in thymic carcinoma (TC). We also investigated the relationships between these immune checkpoint proteins and the EMT status and examined the impact of induction chemotherapy on patients with tumors that express these proteins.

Methods

The relationship between PD‐1 + TILs/PD‐L1 and clinicopathological findings including EMT was investigated by immunohistochemistry (IHC) of surgically resected samples from 43 patients with TC. In 15 patients receiving induction therapy (IT), those factors were compared before and after IT.

Results

With IHC, 26 cases (60.5%) were positive for PD‐L1, and 19 cases were positive for PD‐1 + TILs (44.2%). The disease‐free survival rate in patients showing EMT and who were PD‐1/PD‐L1 positive was significantly worse compared to negative cases (EMT; P = 0.0095, PD‐1; P = 0.001, PD‐L1; P = 0.0037). We found a significant relationship between PD‐L1 and EMT status (P = 0.01). In patients who received IT, PD‐L1 increased, and the change was strongly correlated with EMT status (P = 0.01).

Conclusion

Epithelial‐mesenchymal transition, PD‐L1, and PD‐1 + TILs have prognostic impact, and PD‐L1 is correlated with EMT status. PD‐L1 expression after IT was significantly higher compared to before IT and was correlated with the EMT change. Thus, PD‐L1 may be upregulated during EMT, and anti‐PD‐1/PD‐L1 immunotherapy may provide reliable treatment of TC in combination with chemotherapy.

Deregulated MicroRNAs in Cancer-Associated Fibroblasts from Front Tumor Tissues of Lung Adenocarcinoma as Potential Predictors of Tumor Promotion

Cancer-associated fibroblasts (CAFs) are the main component of the tumor stroma and promote tumor progression through several mechanisms. Recent evidence indicates that small noncoding RNAs, microRNAs (miRNAs), play key roles in CAF tumor-promoting properties; however, the role of miRNAs in lung cancer-associated fibroblasts remains poorly defined. We characterized the differential miRNA expression profile of fibroblasts isolated from matched tumor front (F-CAFs), inner tumor (In-CAFs), and normal adjacent (NFs) tissues from four lung adenocarcinoma patients (ADs) using microarray analysis. Proliferation and invasion assays of A549 human lung cancer cells in the presence of conditioned medium from F-CAFs, In-CAFs or NFs were performed to assess tumorigenic properties. Ten identified candidate miRNAs in F-CAFs, In-CAFs and NFs from 12 ADs were then validated by RT-PCR. Both F-CAFs and In-CAFs enhanced the proliferation and invasion of A549 cells compared with NFs; moreover, F-CAFs showed a significantly stronger effect than In-CAFs. RT-PCR validation demonstrated three downregulated miRNAs in F-CAFs compared with NFs (miR-145-3p, miR-299-3p, and miR-505-3p), two in F-CAFs compared with In-CAFs (miR-410-3p and miR-485-5p), but no differentially expressed miRNAs between In-CAFs and NFs. Further target-gene prediction and pathway enrichment analysis indicated that deregulated miRNAs in F-CAFs showed significant associations with "pathways in cancer" (miR-145-3p, miR-299-3p and miR-410-3p), "Wnt signaling pathway" (miR-410-3p and miR-505-3p), and "TGF-beta signaling pathway" (miR-410-3p). Importantly, a tumor-promoting growth factor targeted by those miRNAs, VEGFA, was upregulated in F-CAFs compared with NFs, as judged by RT-PCR. In conclusion, deregulated miRNAs in F-CAFs are potentially associated with CAF tumor-promoting properties.

Bioinstructive microparticles for self-assembly of mesenchymal stem Cell-3D tumor spheroids

3D multicellular tumor spheroids (3D-MCTS) that closely mimic in vitro the complex lung tumor microenvironment (TME) are highly desirable for screening innovative anti-cancer therapeutics. Despite significant improvements in mimicking lung TME, few models have combined tumor-infiltrating mesenchymal stem cells from bone marrow (hBM-MSCs) with heterotypic 3D tumor spheroid models containing ECM mimetic components. Herein, we engineered hybrid 3D-MCTS that combine, for the first time, A549:fibroblasts:hBM-MSCs in heterotypic tri-culture, with bioinstructive hyaluronan microparticles that act as tumor-ECM mimetics and as cell-anchoring hotspots. The obtained results indicated that 3D microspheres provided proper support for cells to self-assemble into compact 3D microtissues and promoted an increase in CD44 expression, emulating the presence of native-ECM hyaluronan. 3D-MCTS size and sphere-like morphology was reproducible and tri-culture models presented the characteristic solid tumors necrotic core. Mesenchymal stem cells tracking demonstrated that hBM-MSCs migrate to different regions in 3D microtumors mass exhibiting dynamic interactions with cancer cells and stromal fibroblasts, alike in human tumors. Importantly, doxorubicin administration revealed hBM-MSCs effect on cytotoxic responses in 3D tri-culture models and in dual cultures of hBM-MSCs:A549 at 10:1 ratio. Such findings evidence the relevance of including hBM-MSCs in combination with cancer-stromal fibroblasts in 3D in vitro tumor models and the importance to test different cell-to-cell ratios to mimic tumor heterogeneity. In addition, bioinstructive hyaluronan-microparticles were also effective as cell-agglomerating scaffolds and showed potential to be used as an enabling technology for including different ECM components in 3D in vitro models in the future.

Humanization of the Prostate Microenvironment Reduces Homing of PC3 Prostate Cancer Cells to Human Tissue-Engineered Bone

The primary tumor microenvironment is inherently important in prostate cancer (PCa) initiation, growth and metastasis. However, most current PCa animal models are based on the injection of cancer cells into the blood circulation and bypass the first steps of the metastatic cascade, hence failing to investigate the influence of the primary tumor microenvironment on PCa metastasis. Here, we investigated the spontaneous metastasis of PC3 human PCa cells from humanized prostate tissue, containing cancer-associated fibroblasts (CAFs) and prostate lymphatic and blood vessel endothelial cells (BVECs), to humanized tissue-engineered bone constructs (hTEBCs) in NOD-SCID IL2Rγ^null (NSG) mice. The hTEBC formed a physiologically mature organ bone which allowed homing of metastatic PCa cells. Humanization of prostate tissue had no significant effect on the tumor burden at the primary site over the 4 weeks following intraprostatic injection, yet reduced the incidence and burden of metastases in the hTEBC. Spontaneous PCa metastases were detected in the lungs and spleen with no significant differences between the humanized and non-humanized prostate groups. A significantly greater metastatic tumor burden was observed in the liver when metastasis occurred from the humanized prostate. Together, our data suggests that the presence of human-derived CAFs and BVECs in the primary PCa microenvironment influences selectively the metastatic and homing behavior of PC3 cells in this model. Our orthotopic and humanized PCa model developed via convergence of cancer research and tissue engineering concepts provides a platform to dissect mechanisms of species-specific PCa bone metastasis and to develop precision medicine strategies.

Revisiting the dynamic cancer stem cell model: Importance of tumour edges

The lack of an effective treatment against cancer is not only due to its huge heterogeneity, but also to the fact that we don't have an answer to the question on how cancer originates. Among the proposed models to explain the development of cancer, the hierarchical model has been widely accepted. Nevertheless, this model fails to explain several experimental observations such as the cancer stem cells (CSCs) location inside a tumour or the differences between primary and metastatic tumours. Moreover, increasing evidence shows that the CSC phenotype is not a rigid state. Here, we present a critical review on the assumed tumour development models emphasizing the relevance of the dynamic and changing nature of cancer and the CSCs population in which the tumour microenvironment plays a crucial role and we propose a new model of tumour origin that could have an impact on new therapeutic strategies.

Characterization and In Vivo Validation of a Three-Dimensional Multi-Cellular Culture Model to Study Heterotypic Interactions in Colorectal Cancer Cell Growth, Invasion and Metastasis

Colorectal cancer (CRC) is the third cause of cancer-related mortality in industrialized countries. Local invasion and metastasis formation are events associated with poor prognosis for which today there are no effective therapeutic options. Invasion and metastasis are strongly modulated by cells of the tumor microenvironment (TME), in particular fibroblasts and endothelial cells. Unraveling interactions between tumor cells and cells of the TME may identify novel mechanisms and therapeutic targets to prevent or treat metastasis. We report here the development and in vivo validation of a 3D tumor spheroid model to study the interactions between CRC cells, fibroblasts and endothelial cells in vitro. Co-cultured fibroblasts promoted SW620 and HCT116 CRC spheroid invasion, and this was prevented by the SRC and FGFR kinase inhibitors Dasatinib and Erdafitinib, respectively. To validate these findings in vivo, we injected SW620 cells alone or together with fibroblasts orthotopically in the caecum of mice. Co-injection with fibroblasts promoted lung metastasis growth, which was fully reversed by treatment with Dasatinib or Erdafitinib. Co-culture of SW620 or HCT116 CRC spheroids with endothelial cells suppressed spheroid growth while it had no effect on cancer cell migration or invasion. Consistent with this in vitro effect, co-injected endothelial cells significantly inhibited primary tumor growth in vivo. From these experiments we conclude that effects on cancer cell invasion and growth induced by co-cultured TME cells and drug treatment in the 3D spheroid model in vitro, are predictive of in vivo effects. The 3D spheroid model may be considered as an attractive model to study the effect of heterotypic cellular interactions and drug activities on cancer cells, as animal testing alternative. This model may be adapted and further developed to include different types of cancer and host cells and to investigate additional functions and drugs.

Current perspectives on the crosstalk between lung cancer stem cells and cancer-associated fibroblasts

Lung cancer, in particular non-small cell lung carcinoma (NSCLC), is the second most common cancer in both men and women and the leading cause of cancer-related deaths worldwide. Its prognosis and diagnosis are determined by several driver mutations and diverse risk factors (e.g. smoking). While immunotherapy has proven effective in some patients, treatment of NSCLC using conventional chemotherapy is largely ineffective. The latter is believed to be due to the existence of a subpopulation of stem-like, highly tumorigenic and chemoresistant cells within the tumor population known as cancer stem cells (CSC). To complicate the situation, CSCs interact with the tumor microenvironment, which include cancer-associated fibroblasts (CAFs), immune cells, endothelial cells, growth factors, cytokines and connective tissue components, which via a dynamic crosstalk, composed of proteins and exosomes, activates the CSC compartment. In this review, we analyze the crosstalk between CSCs and CAFs, the primary component of the NSCLC microenvironment, at the molecular and extracellular level and contemplate therapies to disrupt this communication.

Gas6 derived from cancer-associated fibroblasts promotes migration of Axl-expressing lung cancer cells during chemotherapy

Alterations to the tumor stromal microenvironment induced by chemotherapy could influence the behavior of cancer cells. In the tumor stromal microenvironment, cancer-associated fibroblasts (CAFs) play an important role. Because the receptor tyrosine kinase Axl and its ligand Gas6 could be involved in promoting non-small cell lung cancer (NSCLC), we investigated the role of Gas6 secreted by CAFs during chemotherapy in NSCLC. In a murine model, we found that Gas6 expression by CAFs was upregulated following cisplatin treatment. Gas6 expression might be influenced by intratumoral hypoperfusion during chemotherapy, and it increased after serum starvation in a human lung CAF line, LCAF^hTERT. Gas6 is associated with LCAF^hTERT cell growth. Recombinant Gas6 promoted H1299 migration, and conditioned medium (CM) from LCAF^hTERT cells activated Axl in H1299 cells and promoted migration. Silencing Gas6 in LCAF^hTERT reduced the Axl activation and H1299 cell migration induced by CM from LCAF^hTERT. In clinical samples, stromal Gas6 expression increased after chemotherapy. Five-year disease-free survival rates for patients with tumor Axl- and stromal Gas6-positive tumors (n = 37) was significantly worse than for the double negative group (n = 12) (21.9% vs 51.3%, p = 0.04). Based on these findings, it is presumed that Gas6 derived from CAFs promotes migration of Axl-expressing lung cancer cells during chemotherapy and is involved in poor clinical outcome.

Chemotherapy enhances programmed cell death 1/ligand 1 expression via TGF-β induced epithelial mesenchymal transition in non-small cell lung cancer

In cancer immunology, the programmed cell death 1-programmed cell death 1/ligand 1 (PD-1/PD-L1) pathway plays a major role. Anti-PD-1 and anti-PD-L1 antibodies provide reliable immunotherapy when given as treatment for various types of malignancy including lung cancer. PD-L1 expression in cancer cells has been reported to be a predictive factor for the therapeutic effects of immunotherapy. However, the mechanism of PD-L1 expression remains unclear. Another key process in cancer progression is epithelial-mesenchymal transition (EMT). In the present study, we investigated the mechanism of PD-L1 expression as well as changes in its expression during the EMT process in non-small cell lung cancer (NSCLC). In this study, A549 cells underwent EMT by treatment with TGF-β or chemotherapeutic agents and then PD-L1 expression was evaluated. The alterations of PD-L1 expression was also examined during the reverse EMT process; mesenchymal-epithelial transition (MET). The relationship between for PD-L1 expression and EMT status in clinical specimens with NSCLC after induction chemotherapy were analyzed by immunohistochemical staining. We found that PD-L1 expression was upregulated following TGF-β induction; in contrast, it was downregulated by TGF-β receptor-kinase inhibitors and the MET process. Furthermore, chemo-treatment increased TGF-β expression and enhances PD-L1 expression via autocrine TGF-β induced EMT. Analysis of clinical samples revealed a significant relationship between PD-L1 expression and EMT status (P<0.05). In conclusion, our results suggest that PD-L1 expression is regulated by TGF-β induced EMT and enhanced by chemo-treatment via the chemo-induced TGF-β signaling. The anti-PD-1/PD-L1 blockade may provide more effective anticancer activities in combination with chemotherapy in NSCLC.

Cancer-associated fibroblasts enhance metastatic potential of lung cancer cells through IL-6/STAT3 signaling pathway

Recent studies indicate that cancer-associated fibroblasts (CAFs) are involved in tumor growth, invasion and metastasis, however, the underling mechanisms remain unclear. In the present study, we investigated the role of CAFs on the metastatic potential of lung cancer cells. The stromal fibroblasts we isolated from lung cancer tissues presented CAFs characteristics with high levels of α-smooth muscle actin (α-SMA) and fibroblast-activating protein (FAP). Our data showed that the conditioned medium from cultured CAFs (CAF-CM) dramatically enhanced migration and invasion of lung cancer cells. CAF-CM induced epithelial-mesenchymal transition (EMT) by regulating the expression of EMT-associated markers E-cadherin and vimentin, and also modulated metastasis-related genes MMP-2 and VEGF both in vitro and in vivo. Further mechanistic studies demonstrated that CAFs enhanced the metastatic potential of lung cancer cells by secreting IL-6, subsequently activating of JAK2/STAT3 signaling pathway. Additionally, the inhibition of IL-6/STAT3 signaling pathway by IL-6 neutralizing antibody or specific inhibitors of JAK2/STAT3 reversed CAF-CM induced EMT and migration of lung cancer cells. Taken together, these findings revealed a novel mechanism that CAFs induced EMT and promoted metastasis of lung cancer cells through the IL-6/STAT3 signaling pathway.

Pirfenidone plays a biphasic role in inhibition of epithelial-mesenchymal transition in non-small cell lung cancer

INTRODUCTION

Epithelial to mesenchymal transition (EMT) relates to both organ fibrosis and malignant behavior of cancer. Pirfenidone (PFD) is an anti-fibrotic agent for idiopathic pulmonary fibrosis and one of its functions may be to inhibit fibrotic EMT. This study aimed to investigate the possibility that PFD might exert an anti-tumor effect through inhibition of EMT in non-small cell lung cancer (NSCLC) cell lines in vitro and in vivo.

METHODS

NSCLC cells (A549, NCI-H358) were used to evaluate PFD effects on TGF-β1 induced phenotypic changes. Possible TGF-β1 signaling pathways modulated by PFD were evaluated. The effects of PFD on EMT induced by an anti-cancer drug was also analyzed. The impact of PFD on tumor growth in nude mice as well as on EMT change in vivo was also determined.

RESULTS

PFD significantly inhibited TGF-β1-induced EMT. Smad2 phosphorylation and TGF-β1 receptor I expression were also inhibited as was translocation of Smad2 from the cytoplasm into the nucleus. Carboplatin induced elevation of TGF-β1 production from cancer cells together with induction of EMT, which were suppressed by co-treatment with PFD. In in vivo examination, PFD alone did not inhibit tumor progression whereas its combination with carboplatin significantly decreased tumor growth. Immunohistological analysis showed that PFD suppressed EMT change induced by carboplatin.

CONCLUSIONS

PFD could attenuate the EMT process induced not only by exogenous TGF-β1 but also by paracrine TGF-β produced from NSCLC cells. PFD may be a promising new therapeutic agent for the treatment of NSCLC through the regulation of EMT.

Concomitant Interstitial Lung Disease Is a Risk Factor for Pleural Invasion in Lung Cancer

BACKGROUND

Lung carcinoma is often associated with interstitial lung disease (ILD), and the prognosis of lung cancer accompanied by ILD is unfavorable. In this study, cases of patients with primary lung cancer with or without ILD were reviewed to analyze surgical outcome, with special interest in the conformity of clinical and pathologic stages, pathologic findings of pleural invasion, malignant pleurisy first detected at the time of thoracotomy, and survival.

METHODS

Retrospective chart review was performed for 1,264 primary lung cancer patients who underwent surgery from 2004 to 2015. Concomitant ILD was diagnosed by pathological examination or preoperative chest computed tomography findings.

RESULTS

ILD was found in 104 patients (8.2%) with primary lung cancer. Conformity of clinical and pathological stages in the ILD-positive patients was poor, with a lower kappa value than that for the 1,160 ILD-negative patients (0.34 versus 0.51). The ILD group had significantly higher incidences of pleural invasion and unexpected malignant pleurisy than did the non-ILD group (for pleural invasion, 49.0% versus 24.5%, p < 0.0001; for malignant pleurisy, 7.69% versus 1.47%, p < 0.0001). The 5-year overall survival rates of the ILD group showed significantly lower than those of the non-ILD group (45.2% versus 70.1%; p = 0.0014) after propensity score matching.

CONCLUSIONS

In lung cancer, the concomitant existence of ILD is a risk factor for pleural invasion. Concomitant ILD might cause underestimation of clinical staging, increase the chance of unexpected malignant pleurisy during surgery, and shorten survival time.

Biology of lung cancer: genetic mutation, epithelial-mesenchymal transition, and cancer stem cells

At present, most cases of unresectable cancer cannot be cured. Genetic mutations, EMT, and cancer stem cells are three major issues linked to poor prognosis in such cases, all connected by inter- and intra-tumor heterogeneity. Issues on inter-/intra-tumor heterogeneity of genetic mutation could be resolved with recent and future technologies of deep sequencers, whereas, regarding such issues as the "same genome, different epigenome/phenotype", we expect to solve many of these problems in the future through further research in stem cell biology. We herein review and discuss the three major issues in the biology of cancers, especially from the standpoint of stem cell biology.

The Microenvironment of Lung Cancer and Therapeutic Implications

The tumor microenvironment (TME) represents a milieu that enables tumor cells to acquire the hallmarks of cancer. The TME is heterogeneous in composition and consists of cellular components, growth factors, proteases, and extracellular matrix. Concerted interactions between genetically altered tumor cells and genetically stable intratumoral stromal cells result in an "activated/reprogramed" stroma that promotes carcinogenesis by contributing to inflammation, immune suppression, therapeutic resistance, and generating premetastatic niches that support the initiation and establishment of distant metastasis. The lungs present a unique milieu in which tumors progress in collusion with the TME, as evidenced by regions of aberrant angiogenesis, acidosis and hypoxia. Inflammation plays an important role in the pathogenesis of lung cancer, and pulmonary disorders in lung cancer patients such as chronic obstructive pulmonary disease (COPD) and emphysema, constitute comorbid conditions and are independent risk factors for lung cancer. The TME also contributes to immune suppression, induces epithelial-to-mesenchymal transition (EMT) and diminishes efficacy of chemotherapies. Thus, the TME has begun to emerge as the "Achilles heel" of the disease, and constitutes an attractive target for anti-cancer therapy. Drugs targeting the components of the TME are making their way into clinical trials. Here, we will focus on recent advances and emerging concepts regarding the intriguing role of the TME in lung cancer progression, and discuss future directions in the context of novel diagnostic and therapeutic opportunities.

The hypoxic tumor microenvironment: driving the tumorigenesis of non-small-cell lung cancer

Since the application of molecular biology in cancer biology, lung cancer research has classically focused on molecular drivers of disease. One such pathway, the hypoxic response pathway, is activated by reduced local oxygen concentrations at the tumor site. Hypoxia-driven gene and protein changes enhance epithelial-to-mesenchymal transition, remodel the extracellular matrix, drive drug resistance, support cancer stem cells and aid evasion from immune cells. However, it is not the tumor cells alone which drive this response to hypoxia, but rather their interaction with a complex milieu of supporting cells. This review will focus on recent advances in our understanding of how these cells contribute to the tumor response to hypoxia in non-small-cell lung cancer.

Lung cancer-associated myofibroblasts reveal distinctive ultrastructure and function

BACKGROUND

Cancer-associated stromal cells interact with carcinoma cells and thus participate in tumor growth. Our aim was to characterize the ultrastructure and contractile properties of stromal cells in collagen gel cultured from lung cancer of various histological types and from tumor-free lung.

METHODS

Cells cultured from lung cancer (13 adenocarcinomas, six squamous cell carcinomas, one adenosquamous carcinoma, and one pleomorphic carcinoma) and tumor-free lung were analyzed by transmission electron microscopy and three-dimensional collagen gel contraction assays. The expression of α-smooth muscle actin (α-SMA), a recognized myofibroblast marker, was examined by immunoelectron microscopy from individual cells and by Western blotting from the whole cultured cell population.

RESULTS

According to their ultrastructure, the cell lines were composed of fibroblastic and myofibroblastic cells. In electron microscopy, cells of lung cancer exhibited more myofibroblastic features displaying higher amounts of actin belts (p = 0.057) and α-SMA labeling (p = 0.010) than cells from tumor-free lung. Myofibroblasts cultured from lung cancer of smokers expressed less α-SMA labeling (p = 0.013) than counterparts from nonsmokers. Western blotting revealed that cancer-associated fibroblasts expressed more α-SMA (p = 0.006) than cells from tumor-free lung, whereas cells from tumor-free central lung of smokers showed less α-SMA (p = 0.039) than counterparts from nonsmokers. Cells cultured from cancer contracted more in collagen gel than those from tumor-free lung. The contractile capacity in collagen gel correlated with the frequency of extracellular component of fibronexus by transmission electron microscopy.

CONCLUSIONS

Lung cancer-associated myofibroblasts are different both ultrastructurally and functionally when compared with cells cultured from tumor-free lung. Smoking altered myofibroblastic phenotype, regardless of their origin.

High p-Smad2 expression in stromal fibroblasts predicts poor survival in patients with clinical stage I to IIIA non-small cell lung cancer

BACKGROUND

Increasing evidence indicates that the TGFβ/Smad signaling pathway plays a prominent role in tumor initiation, progression, and metastasis. Therefore, we investigate the expression of p-Smad2 in surgical resection specimens from non-small cell lung cancer, and evaluate the prognostic significance of p-Smad2 expression in stromal fibroblasts and cancer cells for patients with clinical stage I to IIIA non-small cell lung cancer.

METHODS

The immunohistochemical expression of p-Smad2 was evaluated in 78 formalin-fixed paraffin-embedded surgical resection specimens from clinical stage I to IIIA non-small cell lung cancer. Correlations between p-Smad2 expression and clinicopathologic characteristics were determined by Chi-square test. The prognostic significance of p-Smad2 expression in stromal fibroblasts and cancer cells with regard to overall survival was determined by Kaplan-Meier.

RESULTS

There were 38.5% (30/78) and 92.3% (72/78) patients with high p-Smad2 expression in stromal fibroblasts and cancer cells, respectively. There was a positive correlation between the p-Smad2 expression level in stromal fibroblasts and the p-Smad2 expression level in cancer cells (χ2=4.176, P=0.045). No significant correlation of p-Smad2 expression in stromal fibroblasts or cancer cells with any of clinicopathologic characteristics was found. The 3-year overall survival rates with low and high p-Smad2 expression in stromal fibroblasts were 53.7% and 37.7%, respectively (χ2=3.86, P=0.049). No significant association was found between low and high p-Smad2 expression in cancer cells with respect to overall survival, respectively (χ2=0.34, P=0.562).

CONCLUSIONS

The results suggested that high p-Smad2 expression in stromal fibroblasts predicted poor survival in patients with clinical stage I to IIIA non-small cell lung cancer.

Bioinformatic approaches to augment study of epithelial-to-mesenchymal transition in lung cancer

Bioinformatic approaches are intended to provide systems level insight into the complex biological processes that underlie serious diseases such as cancer. In this review we describe current bioinformatic resources, and illustrate how they have been used to study a clinically important example: epithelial-to-mesenchymal transition (EMT) in lung cancer. Lung cancer is the leading cause of cancer-related deaths and is often diagnosed at advanced stages, leading to limited therapeutic success. While EMT is essential during development and wound healing, pathological reactivation of this program by cancer cells contributes to metastasis and drug resistance, both major causes of death from lung cancer. Challenges of studying EMT include its transient nature, its molecular and phenotypic heterogeneity, and the complicated networks of rewired signaling cascades. Given the biology of lung cancer and the role of EMT, it is critical to better align the two in order to advance the impact of precision oncology. This task relies heavily on the application of bioinformatic resources. Besides summarizing recent work in this area, we use four EMT-associated genes, TGF-β (TGFB1), NEDD9/HEF1, β-catenin (CTNNB1) and E-cadherin (CDH1), as exemplars to demonstrate the current capacities and limitations of probing bioinformatic resources to inform hypothesis-driven studies with therapeutic goals.

Simultaneous expression of cancer stem cell-like properties and cancer-associated fibroblast-like properties in a primary culture of breast cancer cells

The importance of cancer-associated fibroblasts (CAFs) in cancer biology has been recently highlighted owing to their critical roles in cancer growth, progression, metastasis, and therapeutic resistance. We have previously established a primary culture of breast cancer cells, which showed epithelial-mesenchymal transition and cancer stem cell-like properties. In this study, we found that the primary culture also showed CAF-like properties. For example, hypoxia inducible factor 1α (HIF1A) and its downstream genes, nuclear factor-kappa B2 (NF-κB2) and BCL2/adenovirus E1B 19 kd-interacting protein 3 (BNIP3), and many enzymes involved in glycolysis, such as GAPDH, LDH, PGAM1, and PKM2, were highly overexpressed in the primary culture. Moreover, media conditioned with the primary culture cells enhanced the growth of breast cancer cells. Similar to previous CAF studies, this enhancement suggested to be occurred through fibroblast growth factor signaling. This MCKH primary culture cell, which showed simultaneous expression of tumorigenic and CAF properties, offers a unique experimental system for studying the biology of CAFs.

Stemness and plasticity of lung cancer cells: paving the road for better therapy

Lung cancer is a devastating disease that is responsible for around 160,000 deaths each year in United States. The discovery that lung cancer, like most other solid tumors, contains a subpopulation of cancer stem cells or cancer stem-like cells (CSCs/CS-LCs) that if eliminated could lead to a cure has brought new hope. However, the exact nature of the putative lung CSCs/CS-LCs is not known and therefore therapies to eliminate this subpopulation have been elusive. A limited knowledge and understanding of cancer stem cell properties and tumor biology may be responsible for the limited clinical success. In this review we discuss the stemness and plasticity properties of lung cancer cells that are critical aspects in terms of developing effective therapies. We suggest that the available experimental evidence obtained from lung cancer cell lines and patients’ derived primary cultures does not support a tumor model consistent with the classical CSC model. Instead, all lung cancer cells may be extremely versatile and new models of cancer stem cells may be better working models.

Interaction between non-small-cell lung cancer cells and fibroblasts via enhancement of TGF-β signaling by IL-6

INTRODUCTION

Fibroblasts are key components of the tumor microenvironment. We clarified the role of transforming growth factor (TGF)-β and interleukin (IL)-6 in the interaction between fibroblasts and non-small-cell lung cancer (NSCLC) cells.

METHODS

We used NSCLC cells (A549, NCI-H358) and normal human lung fibroblast (NHLF) cells to evaluate phenotypic changes in the presence of human IL-6, TGF-β1, and conditioned media (CM) from these cells. Possible pathways were evaluated with SB431542, a TGF-β receptor inhibitor, or an anti-human IL-6 receptor neutralizing antibody (IL-6R-Ab).

RESULTS

A549 and NCI-H358 cells incubated with IL-6 (50 ng/mL) and TGF-β1 (2 ng/mL) showed significantly increased epithelial-mesenchymal transition (EMT) signaling compared to those treated with TGF-β1 alone. Furthermore, NHLF cells were synergistically activated by IL-6 and TGF-β1. IL-6 increased the expression of TGF-β type I receptors on the surface of A549, NCI-H358 and NHLF cells and enhanced TGF-β signaling. TGF-β1 induced phenotypic changes were attenuated by IL-6R-Ab. NHLF cells were activated and A549 cells showed induction of EMT in response to CM from the other cell type. These activities were attenuated by SB431542 or IL-6R-Ab, suggesting that interplay between NSCLC cells and NHLF may lead to increased EMT signaling in NSCLC cells and activation of NHLF cells through TGF-β and IL-6 signaling. Subcutaneous co-injection of A549 and NHLF cells into mice resulted in a high rate of tumor formation compared with injection of A549 cells without NHLF cells. SB431542 or IL-6R-Ab also attenuated the tumor formation enhanced by co-injection of the two cell types.

CONCLUSION

IL-6 enhanced epithelial cell EMT and stimulated tumor progression by enhancing TGF-β signaling. IL-6 and TGF-β may play a contributing role in maintenance of the paracrine loop between these two cytokines in the communication between fibroblasts and NSCLC cells for tumor progression.