Carcinoma-associated Fibroblasts Research Articles

Interleukin-6 induces VEGF secretion from prostate cancer cells in a manner independent of androgen receptor activation.

The reduced androgen-sensitivity of prostate cancer (PCa) cells is an important clinical development because of its association with the cells' progression to castration-resistant prostate cancer (CRPC). During androgen deprivation therapy (ADT), stroma-derived growth factors and cytokines can activate the androgen receptor (AR). For example, IL-6 is a multifunctional cytokine that is involved in the malignancy of PCa cells through AR activation. In the present study, we used an androgen-sensitive human PCa cell line (LNCaP) and its sublines to investigate the relationship between the responsiveness of PCa cells to IL-6 treatment and the cellular AR signaling pathway. The androgen-low-sensitive F10 and E9 cells were obtained from LNCaP cells by limiting dilution method in regular culture condition. In contrast, the androgen-insensitive AIDL cells were established from LNCaP cells by continuous passaging in hormone-depleted condition. Original carcinoma-associated fibroblasts (CAFs) PCaSC-8 and PCaSC-9 cells were isolated from needle biopsy samples of PCa patients. In fibroblasts derived from PCa patients, IL-6 secretion was generally higher than that observed with normal fibroblasts. In contrast, IL-6 secretion was not detected in LNCaP and its sublines. The soluble IL-6 receptor was detected in PCa cells but not in fibroblasts. IL-6 treatment suppressed cell growth of LNCaP, F10, and E9 cells but not AIDL cells and it was accompanied with neuroendocrine-like differentiation. Induction of PSA secretion was observed in IL-6-treated LNCaP and F10 cells. VEGF secretion was strongly induced in IL-6-treated LNCaP and AIDL cells. IL-6-induced VEGF secretion was significantly suppressed by a PI3K inhibitor (LY294002) and it was accompanied by inhibited phosphorylation of Akt. Our results suggest that IL-6 might induce VEGF secretion from PCa cells in a manner independent of AR activation. To prevent IL-6-induced VEGF secretion, inhibition of the PI3K/AKT signaling pathway could be an important pharmacological goal regardless of ADT.

Long-term exposure to carcinoma-associated fibroblasts makes breast cancer cells addictive to integrin β1.

We studied the long-term effect of stromal factors on the development of fulvestrant-resistance (FR) and fulvestrant-induced dormancy (D). Sublines established from stroma-treated FR-cells (C-FR cells) and D-cells (C-D cells) show permanently high expression of integrin β1 as well as Bcl-3 and P-STAT3 (C-FR) or IGF1R (C-D). Yet, cells fail to withstand fulvestrant better and do not migrate or grow faster than control cells. Instead, C-D cells rely on stromal factors to perform as well as control cells. In addition, C-FR cells adapted to integrin β1 for growth in 3D cultures. These data suggest that long-term exposure to stromal factors leads to addiction rather than better performance in cellular activities. We also found that morphologically distinct breast cancer cell line subpopulations share key responses to stromal factors suggesting that intratumoral heterogeneity may play a minor role in the interaction between breast cancer and stromal cells.

Role of Stromal Paracrine Signals in Proliferative Diseases of the Aging Human Prostate.

Androgens are essential for the development, differentiation, growth, and function of the prostate through epithelial–stromal interactions. However, androgen concentrations in the hypertrophic human prostate decrease significantly with age, suggesting an inverse correlation between androgen levels and proliferative diseases of the aging prostate. In elderly males, age- and/or androgen-related stromal remodeling is spontaneously induced, i.e., increased fibroblast and myofibroblast numbers, but decreased smooth muscle cell numbers in the prostatic stroma. These fibroblasts produce not only growth factors, cytokines, and extracellular matrix proteins, but also microRNAs as stromal paracrine signals that stimulate prostate epithelial cell proliferation. Surgical or chemical castration is the standard systemic therapy for patients with advanced prostate cancer. Androgen deprivation therapy induces temporary remission, but the majority of patients eventually progress to castration-resistant prostate cancer, which is associated with a high mortality rate. Androgen deprivation therapy-induced stromal remodeling may be involved in the development and progression of castration-resistant prostate cancer. In the tumor microenvironment, activated fibroblasts stimulating prostate cancer cell proliferation are called carcinoma-associated fibroblasts. In this review, we summarize the role of stromal paracrine signals in proliferative diseases of the aging human prostate and discuss the potential clinical applications of carcinoma-associated fibroblast-derived exosomal microRNAs as promising biomarkers.

The aggressive nature of prostate cancer of African Americans is correlated with massive down‐regulation of many immunoregulatory genes of microenvironment

BackgroundThe overall survival of prostate cancer for African Americans (AAs) is significantly worse than for European‐Americans (EA) which cannot be attributed to social‐economic status and may be related to racial‐genetic differences. We previously applied expression analysis (U133A) and observed significantly decreased expression of AA patient compared to EA patients especially in the tumor‐adjacent stroma. We tested the hypothesis that gene express in the stroma AA patients was significantly decreased compared to EA.MethodsWe developed primary cultures of turmor‐adjacent carcinoma‐associated fibroblasts (CAFs) of AA and EA tumors and matching distant contralateral fibroblasts (dCAFs), ~100 lines in all. We examined secretion of immunomodulators from the CAFs and dCAFs from prostate cancer of AA and EA tumors and distant stroma (dCAFs) as controls and applied RNAseq of the same cells as well as archived FFPE (formal‐fixed paraffin‐embedded) blocks of AA and EA patients.ResultsAll 30 measured secreted immunomodulators were lower for AA CAFs. In contrast, few if any differences were seen between dCAFs of AA and EA. In particular Interferon‐alpha2 (IFN‐a2) is significantly reduced which is in keeping with the reduced immunomodulatory and Interferon‐induced genes (ISGs) observed for AA patients. The widespread reduction in immunomodulatory chemokines and cytokines observed in AA CAF supernatants suggests a state of significant immunosuppression as compared to the EA CAFs. The higher expression levels of chemokines Eotaxin, IP‐10, MIP1‐a, MIP‐1b, and MCP‐1, in the EA stroma may attract and activate immune cells to the tumor microenvironment thereby improving prognosis. Higher levels of several of inflammatory cytokines such as IL‐17, IL‐12, IL‐1a, IL‐1b in EA patients also may help activate immune cells leading to greater inflammation and immune responses in EA patients. The RNAseq data of AA and EA CAFs and for the FFPE tissue of AA and EA patients supported the decreased expression of the immunomodulatory genes in the stroma of AA patients compared to EA patients.ConclusionThe detection of many statistically significant differences among ISGs and other immunomodulatory genes between the races is supported by RNAseq analysis of FFPE stroma tissue and by in vitro analysis of primary tumor‐adjacent stroma indicating that differences in immunomodulatory mechanisms may be a factor in the poor prognosis of AA prostate cancer. The primary lines of AA and EA CAFs and dCAFs may be a valid system to test role of these factors.Support or Funding InformationDOD/CDMRP W81XWH‐15‐1‐0696This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Carcinoma associated fibroblasts (CAFs) promote breast cancer motility by suppressing mammalian Diaphanous-related formin-2 (mDia2).

The tumor microenvironment (TME) promotes tumor cell invasion and metastasis. An important step in the shift to a pro-cancerous microenvironment is the transformation of normal stromal fibroblasts to carcinoma-associated fibroblasts (CAFs). CAFs are present in a majority of solid tumors and can directly promote tumor cell motility via cytokine, chemokine and growth factor secretion into the TME. The exact effects that the TME has upon cytoskeletal regulation in motile tumor cells remain enigmatic. The conserved formin family of cytoskeleton regulating proteins plays an essential role in the assembly and/or bundling of unbranched actin filaments. Mammalian Diaphanous-related formin 2 (mDia2/DIAPH3/Drf3/Dia) assembles a dynamic F-actin cytoskeleton that underlies tumor cell migration and invasion. We therefore sought to understand whether CAF-derived chemokines impact breast tumor cell motility through modification of the formin-assembled F-actin cytoskeleton. In MDA-MB-231 cells, conditioned media (CM) from WS19T CAFs, a human breast tumor-adjacent CAF line, significantly and robustly increased wound closure and invasion relative to normal human mammary fibroblast (HMF)-CM. WS19T-CM also promoted proteasome-mediated mDia2 degradation in MDA-MB-231 cells relative to control HMF-CM and WS21T CAF-CM, a breast CAF cell line that failed to promote robust MDA-MB-231 migration. Cytokine array analysis of CM identified up-regulated secreted factors in WS19T relative to control WS21T CM. We identified CXCL12 as a CM factor influencing loss of mDia2 protein while increasing MDA-MB-231 cell migration. Our data suggest a mechanism whereby CAFs promote tumor cell migration and invasion through CXCL12 secretion to regulate the mDia2-directed cytoskeleton in breast tumor cells.

CAFs enhance paclitaxel resistance by inducing EMT through the IL‑6/JAK2/STAT3 pathway.

Carcinoma-associated fibroblasts (CAFs) are the major components of mesenchymal cells in the inflammatory tumor microenvironment. They are involved in epithelial-mesenchymal transition (EMT) and chemotherapy resistance by directly contacting with cancer cells or secretory cytokines. In the present study, we examined the role of CAFs in the induction of EMT in ovarian cancer. Primary ovarian cancer cells, CAFs and normal fibroblasts (NFs) were isolated from fresh cancer tissue and cultured for immunohistochemistry studies. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of IL-6 in the culture supernatants of these cells. The expression of IL-6 at the mRNA level was examined by RT-PCR. The expression of IL-6 at the protein level in ovarian cancer tissues was determined using an immunofluorescence assay in both tissue sections and cell lobes. OVCAR3 cells were treated with the culture supernatants collected from CAFs and NFs. IL-6 monoclonal antibody (mAb) was employed to neutralize IL-6. The expression of phosphorylated STAT3 was assessed. Changes in EMT, proliferation, invasion and proapoptotic protein expression were also examined. Flow cytometry was performed to detect the changes in apoptosis resistance of OVCAR3 cells. The JAK2/STAT3 pathway-specific inhibitor AG490 was used to block this pathway and the β-TGF inhibitor was used to inhibit EMT. The clinical data of patients treated in our hospital were collected between January 1st, 2009 and June 30th, 2013. The expression of interstitial IL-6 in paraffin-embedded tissues was detected by immunohistochemistry. The relationship between the expression of interstitial IL-6 and the treatment response was examined by linear regression and multiple linear regression analyses. We found that CAFs were the main source of IL-6 in ovarian cancer tissue. CAFs promoted the phosphorylation of STAT3 in ovarian cancer and enhanced the proliferation, invasion and EMT. Enhanced EMT may lead to apoptosis resistance, inhibitory expression of pro-apoptotic proteins and paclitaxel resistance. A total of 255 patients were enrolled in this retrospective study. Univariate and multivariate analyses revealed that age, CA125, interstitial IL-6 expression and cytoreduction satisfaction were closely related to the sensitivity of the TP (docetaxel plus cisplatin or carbopatin) regimen in ovarian cancer (P<0.05). These results demonstrated that CAFs highly secreted IL-6 and promoted β-TGF-mediated EMT in ovarian cancer via the JAK2/STAT3 pathway, leading to inhibited apoptosis and subsequent paclitaxel resistance. Therefore, CAFs may be a new therapeutic target for the treatment of ovarian cancer.

MiR200-regulated CXCL12\u03b2 promotes fibroblast heterogeneity and immunosuppression in ovarian cancers

High-grade serous ovarian cancers (HGSOC) have been subdivided into molecular subtypes. The mesenchymal HGSOC subgroup, defined by stromal-related gene signatures, is invariably associated with poor patient survival. We demonstrate that stroma exerts a key function in mesenchymal HGSOC. We highlight stromal heterogeneity in HGSOC by identifying four subsets of carcinoma-associated fibroblasts (CAF-S1-4). Mesenchymal HGSOC show high content in CAF-S1 fibroblasts, which exhibit immunosuppressive functions by increasing attraction, survival, and differentiation of CD25+FOXP3+ T lymphocytes. The beta isoform of the CXCL12 chemokine (CXCL12β) specifically accumulates in the immunosuppressive CAF-S1 subset through a miR-141/200a dependent-mechanism. Moreover, CXCL12β expression in CAF-S1 cells plays a crucial role in CAF-S1 immunosuppressive activity and is a reliable prognosis factor in HGSOC, in contrast to CXCL12α. Thus, our data highlight the differential regulation of the CXCL12α and CXCL12β isoforms in HGSOC, and reveal a CXCL12β-associated stromal heterogeneity and immunosuppressive environment in mesenchymal HGSOC.

Inhibition of Nox4-dependent ROS signaling attenuates prostate fibroblast activation and abrogates stromal-mediated protumorigenic interactions.

Carcinoma‐associated fibroblasts (CAFs) play a key onco‐supportive role during prostate cancer (PCa) development and progression. We previously reported that the reactive oxygen species (ROS)‐producing enzyme NADPH oxidase 4 (Nox4) is essential for TGFβ1‐mediated activation of primary prostate human fibroblasts to a CAF‐like phenotype. This study aimed to further investigate the functional relevance of prostatic Nox4 and determine whether pharmacological inhibition of stromal Nox4 abrogates paracrine‐mediated PCa‐relevant processes. RNA in situ hybridization revealed significantly elevated Nox4 mRNA levels predominantly in the peri‐tumoral stroma of clinical PCa with intense stromal Nox4 staining adjacent to tumor foci expressing abundant TGFβ protein levels. At pharmacologically relevant concentrations, the Nox1/Nox4 inhibitor GKT137831 attenuated ROS production, CAF‐associated marker expression and migration of TGFβ1‐activated but not nonactivated primary human prostate fibroblasts. Similar effects were obtained upon shRNA‐mediated silencing of Nox4 but not Nox1 indicating that GKT137831 primarily abrogates TGFβ1‐driven fibroblast activation via Nox4 inhibition. Moreover, inhibiting stromal Nox4 abrogated the enhanced proliferation and migration of PCa cell lines induced by TGFβ1‐activated prostate fibroblast conditioned media. These effects were not restricted to recombinant TGFβ1 as conditioned media from PCa cell lines endogenously secreting high TGFβ1 levels induced fibroblast activation in a stromal Nox4‐ and TGFβ receptor‐dependent manner. Importantly, GKT137831 also attenuated PCa cell‐driven fibroblast activation. Collectively, these findings suggest the TGFβ‐Nox4 signaling axis is a key interface to dysregulated reciprocal stromal–epithelial interactions in PCa pathophysiology and provide a strong rationale for further investigating the applicability of Nox4 inhibition as a stromal‐targeted approach to complement current PCa treatment modalities.

Myofibroblasts in oral potentially malignant disorders: Is it related to malignant transformation?

In oral cancer, acquisition of α-smooth muscle actin (α-SMA)-positive fibroblasts, known as myofibroblasts or carcinoma-associated fibroblasts (CAF), is an important event for progression and metastasis. However, the contribution of myofibroblasts in oral potentially malignant disorders (OPMD) remains controversial. This systematic review provides evidence that immunodetection of myofibroblasts may identify oral submucous fibrosis (OSMF) with high risk of malignant transformation, but does not represent an auxiliary tool to predict the malignant potential of leukoplakia and erythroplakia, the most common OPMD.

Fibroblast Heterogeneity and Immunosuppressive Environment in Human Breast Cancer

Carcinoma-associated fibroblasts (CAF) are key players in the tumor microenvironment. Here, we characterize four CAF subsets in breast cancer with distinct properties and levels of activation. Two myofibroblastic subsets (CAF-S1, CAF-S4) accumulate differentially in triple-negative breast cancers (TNBC). CAF-S1 fibroblasts promote an immunosuppressive environment through a multi-step mechanism. By secreting CXCL12, CAF-S1 attracts CD4+CD25+ T lymphocytes and retains them by OX40L, PD-L2, andJAM2. Moreover, CAF-S1 increases T lymphocyte survival and promotes their differentiation into CD25HighFOXP3High, through B7H3, CD73, and DPP4. Finally, in contrast to CAF-S4, CAF-S1 enhances the regulatory Tcell capacity to inhibit T effector proliferation. These data are consistent with FOXP3+ T lymphocyte accumulation in CAF-S1-enriched TNBC and show how a CAF subset contributes to immunosuppression.

Influences of autophagic regulations of carcinoma associated fibroblasts on the migration and invasion of cocultured colorectal cancer

Objective To explore the influences of autophagic regulations of carcinoma associated fibroblasts (CAFs) on the migration and invasion of cocultured colorectal cancer. Methods CAFs were attempted by primary cultured tissues from colorectal cancer. Autophagic regulation of CAFs was performed using rapamycin and bafilomycin, and autophagic effects were observed with anti-microtubule-associated protein 1 light 3 (LC3). The influences of autophagic regulation of CAFs on the migration and invasion abilities of CCL244 were observed by transwell invasion assay and scratch assay. Western blotting analysis of tumor protein 53 (p53), B-cell lymphoma/leukemia-2 (bcl-2), bcl-2 assaciated X protein (bax), nuclear factor-kappa B (NF-κB) and cysteine-containing aspartate-specific proteases-3 (Caspase-3) were performed determined to investigate the potential mechanisms. Results 400 nmol/L rapamycin increased autophagy and the expression of autophagy associated proteins damage-regulated autophagy modulator (DRAM), autophagy associated gene 5 (Atg5), Beclin-1 and LC3 was up-regulated.400 nmol/L bafilomycin inhibited autophagy of CAFs and the above proteins were down-regulated. We find that rapamycin pretreatment CAFs+ CCL244 group has most tumor cells to across the well (172.0±9.3) and bafilomycin pretreatment CAFs+ CCL244 group has least tumor cells to across the well (52.0±5.0) after each group cells were cultured in transwell in 48 h. The migration rate of CCL-244 cells pretreated in Rapamycin [(15.34±0.49) mm] was especially higher than the bafilomycin pretreatment group, There was no significant difference between the control group and bafilomycin pretreatment group [(10.32±1.08) mm]. Induction of autophagy in CAFs upregulated the expression of bcl-2 and NF-κB and downregulated the expression of bax, p53 and Caspase-3 in irradiated CCL244. Inhibition of autophagy in CAFs showed the opposite results in CCL244. Conclusion Up regulation of autophagy in CAFs can enhance the ability of invasion and migration of cocultured cancer cells, while inhibition of autophagy in CAFs can reduce the invasion and migration ability of cocultured cancer cells. Key words: Colorectal cancer; Carcinoma associated fibroblasts; Autophagy; Regulation; Migration

The expression of pAKT/survivin and their role in colorectal cancer.

595 Background: Colorectal cancer(CRC) is the fourth most prevalent cancer and the leading cause of cancer mortality worldwide. Drug resistance remains the main obstacle to the success of cytotoxic therapies. It is reported that soluble factors released by carcinoma-associated fibroblasts(CAFs) can induce the translocation of AKT, Survivin, P38 to the nucleus of tumor cells, which might be the mechanism of microenvironment-mediated drug resistance to nonspecific conventional chemotherapeutic agents, such as platinum compounds or 5-FU. Methods: Clinicopathological data of colorectal cancer patients who underwent chemotherapy (XELOX or FOLFOX) were collected, followed up and evaluated. p-AKT and survivin expression were assessed by immunohistochemical (IHC) staining. The relationships between p-AKT and survivin expression and patients’ resistance to chemotherapy were analyzed by Chi square respectively. The expression between p-AKT and survivin expression and progression-free survival(PFS) of patients were analyzed by Kaplan-Meier. Results: 51 CRC patients were enrolled in our research. Among them, 21 patients were resistant to chemotherapy(PD), and 30 patients were sensitive to chemotherapy(PR). P-AKT and survivin were assessed by IHC in 47 patients. Among them, 17 patients were p-AKT positive, and 29 patients were survivin positive. Patients of progressive disease(resistant to chemotherapy) were significantly associated with p-AKT positive and survivin positive(p = 0.009, 0.000). Poorer progression-free survival(PFS) was observed in patients with survivin positive compared to those with survivin negative(6.323±0.9m, 13.857±2.664m, Breslow chi square = 4.885, p value = 0.027). There is no significant difference between p-AKT expression and PFS(Breslow chi square = 2.403, p value = 0.121). Conclusions: CRC patients with p-AKT positive or survivin positive were more likely to be resistant to chemotherapeutic agents. CRC patients with survivin positive had a shorter DFS.

CD10+GPR77+ Cancer-Associated Fibroblasts Promote Cancer Formation and Chemoresistance by Sustaining Cancer Stemness

Carcinoma-associated fibroblasts (CAFs) are abundant and heterogeneous stromal cells in tumor microenvironment that are critically involved in cancer progression. Here, we demonstrate that two cell-surface molecules, CD10 and GPR77, specifically define a CAF subset correlated with chemoresistance and poor survival in multiple cohorts of breast and lung cancer patients. CD10+GPR77+ CAFs promote tumor formation and chemoresistance by providing a survival niche for cancer stem cells (CSCs). Mechanistically, CD10+GPR77+ CAFs are driven by persistent NF-κB activation via p65 phosphorylation and acetylation, which is maintained by complement signaling via GPR77, a C5a receptor. Furthermore, CD10+GPR77+ CAFs promote successful engraftment of patient-derived xenografts (PDXs), and targeting these CAFs with a neutralizing anti-GPR77 antibody abolishes tumor formation and restores tumor chemosensitivity. Our study reveals a functional CAF subset that can be defined and isolated by specific cell-surface markers and suggests that targeting the CD10+GPR77+ CAF subset could be an effective therapeutic strategy against CSC-driven solid tumors.

Paracrine and epigenetic control of CAF-induced metastasis: the role of HOTAIR stimulated by TGF-\xdf1 secretion

BackgroundThe communication between carcinoma associated fibroblasts (CAFs) and cancer cells facilitate tumor metastasis. In this study, we further underlying the epigenetic mechanisms of CAFs feed the cancer cells and the molecular mediators involved in these processes.MethodsMCF-7 and MDA-MB-231 cells were treated with CAFs culture conditioned medium, respectively. Cytokine antibody array, enzyme-linked immunosorbent assay, western blotting and immunofluorescence were used to identify the key chemokines. Chromatin immunoprecipitation and luciferase reporter assay were performed to explore the transactivation of target LncRNA by CAFs. A series of in vitro assays was performed with RNAi-mediated knockdown to elucidate the function of LncRNA. An orthotopic mouse model of MDA-MB-231 was conducted to confirm the mechanism in vivo.ResultsHere we reported that TGF-β1 was top one highest level of cytokine secreted by CAFs as revealed by cytokine antibody array. Paracrine TGF-β1 was essential for CAFs induced EMT and metastasis in breast cancer cells, which is a crucial mediator of the interaction between stromal and cancer cells. CAF-CM significantly enhanced the HOTAIR expression to promote EMT, whereas treatment with small-molecule inhibitors of TGF-β1 attenuated the activation of HOTAIR. Most importantly, SMAD2/3/4 directly bound the promoter site of HOTAIR, located between nucleotides -386 and -398, -440 and -452, suggesting that HOTAIR was a directly transcriptional target of SMAD2/3/4. Additionally, CAFs mediated EMT by targeting CDK5 signaling through H3K27 tri-methylation. Depletion of HOTAIR inhibited CAFs-induced tumor growth and lung metastasis in MDA-MB-231 orthotopic animal model.ConclusionsOur findings demonstrated that CAFs promoted the metastatic activity of breast cancer cells by activating the transcription of HOTAIR via TGF-β1 secretion, supporting the pursuit of the TGF-β1/HOTAIR axis as a target in breast cancer treatment.

Reprograming Carcinoma Associated Fibroblasts by microRNAs.

Carcinoma-associated fibroblasts (CAFs) are activated fibroblasts during development of several cancer types, and therefore emerge as an attractive therapeutic target for cancer therapy. Drugs such as PT-100 and sibrotuzumab that block the functions of CAFs have already been in clinical trials. However, these drugs exhibit limited efficacy in patients, partially due to the fact that currently used biomarkers for determining efficacy are not CAF-specific. Furthermore, depletion of CAFs may promote carcinogenesis and accelerate cancer progression by inducing immunosuppression and hypoxia, leading to reduced survival. Accumulating evidence demonstrates that restoring the expression of key microRNA induces the functional conversion of CAFs into normal fibroblasts by targeting different signaling pathways and metabolic mechanisms. Therefore, reprograming CAFs into normal fibroblasts by altering specific expression of microRNAs, rather than targeted ablation, may be an effective, novel strategy for cancer treatment. This review focuses on specific microRNAs involved in the transformation of CAFs as well as their multiple roles during tumorigenesis and chemo-resistance.

Carcinoma-associated fibroblasts promote the stemness and chemoresistance of colorectal cancer by transferring exosomal lncRNA H19.

Long non-coding RNAs (lncRNAs) are involved in the pathology of various tumors, including colorectal cancer (CRC). The crosstalk between carcinoma- associated fibroblasts (CAFs) and cancer cells in the tumor microenvironment promotes tumor development and confers chemoresistance. In this study, we further investigated the underlying tumor-promoting roles of CAFs and the molecular mediators involved in these processes.Methods: The AOM/DSS-induced colitis-associated cancer (CAC) mouse model was established, and RNA sequencing was performed. Small interfering RNA (siRNA) sequences were used to knock down H19. Cell apoptosis was measured by flow cytometry. SW480 cells with H19 stably knocked down were used to establish a xenograft model. The indicated protein levels in xenograft tumor tissues were confirmed by immunohistochemistry assay, and cell apoptosis was analyzed by TUNEL apoptosis assay. RNA-FISH and immunofluorescence assays were performed to assess the expression of H19 in tumor stroma and cancer nests. The AldeRed ALDH detection assay was performed to detect intracellular aldehyde dehydrogenase (ALDH) enzyme activity. Isolated exosomes were identified by transmission electron microscopy, nanoparticle tracking and Western blotting.Results: H19 was highly expressed in the tumor tissues of CAC mice compared with the expression in normal colon tissues. The up-regulation of H19 was also confirmed in CRC patient samples at different tumor node metastasis (TNM) stages. Moreover, H19 was associated with the stemness of colorectal cancer stem cells (CSCs) in CRC specimens. H19 promoted the stemness of CSCs and increased the frequency of tumor-initiating cells. RNA-FISH showed higher expression of H19 in tumor stroma than in cancer nests. Of note, H19 was enriched in CAF-derived conditioned medium and exosomes, which in turn promoted the stemness of CSCs and the chemoresistance of CRC cells in vitro and in vivo. Furthermore, H19 activated the β-catenin pathway via acting as a competing endogenous RNA sponge for miR-141 in CRC, while miR-141 significantly inhibited the stemness of CRC cells.Conclusion: CAFs promote the stemness and chemoresistance of CRC by transferring exosomal H19. H19 activated the β-catenin pathway via acting as a competing endogenous RNA sponge for miR-141, while miR-141 inhibited the stemness of CRC cells. Our findings indicate that H19 expressed by CAFs of the colorectal tumor stroma contributes to tumor development and chemoresistance.

Establishment and characterization of a carcinoma-associated fibroblast cell line derived from a human salivary gland adenoid cystic carcinoma.

Salivary gland adenoid cystic carcinoma (SACC) is one of the most common malignancies in the oral and maxillofacial region. Carcinoma-associated fibroblast (CAF) is an important component in the tumor microenvironment and participates in SACC progression. In this study, we established a CAF cell line derived from a human SACC and named it CAF-SA. It was identified that CAF-SA expressed typical CAF biomarkers. Then, we studied the cellular communications between CAF-SA, tumor cells and endothelial cells. It was found that CAF-SA promoted the migration, invasion, and proliferation of SACC tumor cells in vitro. In addition, tube formation by endothelial cells was enhanced by CAF-SA. In vivo experiment showed that SACC cells formed larger xenografts in nude mice when they were transplanted with CAF-SA. Overall, we demonstrated that CAF-SA exhibited the most important defining feature of CAF by promoting cancer progression.

ELTD1 Function in Hepatocellular Carcinoma is Carcinoma-Associated Fibroblast-Dependent

Introduction: EGF, latrophilin, and seven transmembrane domain containing 1 (ELTD1) constitutes an orphan G-protein-coupled receptor (GPCR) of the adhesion family. High expression of ELTD1 is correlated with favorable prognosis of hepatocellular carcinoma (HCC). After silencing ELTD1 expression, however, tumor invasiveness is drastically reduced. The underlying mechanism of this apparent contradictory phenomenon is unknown. Because adhesion GPCRs couple extracellular adhesion to intracellular signaling, as a member of this family, ELTD1 function may be related to its tumor microenvironment. We therefore investigated the interaction between ELTD1 and the HCC tumor microenvironment.Methods: ELTD1 expression was assessed by immunohistochemical analyses of tissue samples from two independent groups of 333 patients with HCC. Correlations between the ELTD1 expression and the clinicopathological values were examined. We also constructed ELTD1 overexpression and knockdown HCC cell lines and conducted a series of in vivo and in vitro ELTD1 functional assays. We further collected carcinoma associated fibroblast (CAF) culture supernatants to culture HCC cell lines and repeat the respective functional assays in comparison with the control group.Results: Clinicopathologic correlations and in vivo models indicated ELTD1 as a tumor suppressor gene, whereas in vitro experiments suggested that ELTD1 could promote malignancy in HCC cell lines. Immunohistochemical staining of the generated ELTD1 overexpression xenograft tumors demonstrated that the CAF markers vimentin and α-SMA were highly expressed compared to the control group. This suggests that ELTD1 expression is correlated to CAF distribution. In addition, culturing with CAF supernatants inhibited HCC cell proliferation and invasion rates, confirming the correlation between CAF and ELTD1.Conclusion: The results of this study indicated that ELTD1 regulation of HCC progression is CAF-dependent, suggesting that ELTD1 function is regulated by its tumor microenvironment. Further investigation is required to determine the underlying mechanisms.

Role of carcinoma-associated fibroblasts in “anoikis resistance” for oral squamous cell carcinoma: Need of the hour

Role of carcinoma-associated fibroblasts in “anoikis resistance” for oral squamous cell carcinoma: Need of the hour

Erratum: Evaluation of carcinoma-associated fibroblasts in oral squamous cell carcinoma: a potential role for cathepsin K

Erratum: Evaluation of carcinoma-associated fibroblasts in oral squamous cell carcinoma: a potential role for cathepsin K