Cancer-associated fibroblast-derived GAS6 increases resistance to chemotherapy through AXL/STAT3/ABCG1 in gastric cancer.

ObjectiveA significant proportion of patients can not benefit from neoadjuvant chemotherapy (NCT) due to drug resistance. Cancer-associated fibroblasts (CAFs) influence many biological behaviours of tumors, including chemo-resistance. This study aims to explore whether CAFs expressing FAP, CD10, and GPR77 affect the efficacy of NCT and the prognosis of patients with gastric cancer, and its mechanism.MethodsOne hundred seventy-one patients with locally progressive gastric adenocarcinoma who had undergone NCT and radical surgery were collected. Immunohistochemistry was used to detect the expression of FAP, CD10, and GPR77 in CAFs; the EMT markers (N-cadherin, Snail1, and Twist1) and the CSC markers (ALDH1, CD44, and LGR5) in gastric cancer cells. The χ2 test was used to analyze the relationship between the expression of CAF, EMT, and CSC markers and the clinicopathological factors, as well as the relationship between CAF markers and EMT, and CSC markers. Logistic regression and Cox risk regression were used to analyze the relationship between the expression of CAF, EMT, and CSC markers and TRG grading and OS; Kaplan-Meier analysis was used for survival analysis and plotting the curves.ResultsThe expression of CAF markers FAP, CD10, and GPR77 was closely associated with that of EMT markers; FAP and CD10 were closely related to CSC markers. In the univariate analysis of pathological response, CAF markers (FAP, CD10, GPR77), EMT markers (N-cadherin, Snail1, Twist1), and CSC markers (ALDH1, LGR5, CD44), were all closely associated with pathological response (all p < 0.05). Only Twist1 was an independent factor affecting pathological response in multifactorial analysis (p = 0.001). In a univariate analysis of OS, expression of FAP and CD10 in CAF, as well as expression of EMT biomarkers (N-cadherin, Snail1), were significant factors influencing patient prognosis (all p < 0.05). Multifactorial analysis revealed N-cadherin (p = 0.032) and Snail1 (p = 0.028), as independent prognostic factors affecting OS.ConclusionFAP, CD10, and GPR77 labeled CAF subgroup may lead to NCT resistance and poor prognosis by inducing EMT and CSC of gastric cancer cells in locally advanced gastric cancer patients.

Purpose: Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME). Numerous studies have demonstrated a significant correlation between increased CAFs accumulation and poor outcomes in gastric cancer (GC) patients. However, no targeting agents against CAFs have been clinically applied in cancer treatments. AXL, a receptor tyrosine kinase, has emerged as a promising target to suppress cancer cell metastasis, yet AXL inhibitors have not been approved due to limited efficacy in clinical trials. However, the role of AXL upregulated in CAFs remains unexplored. In this study, we investigated the effect of AXL-positive CAFs on GC progression and explore their potential as therapeutic targets to enhance GC treatment efficacy. Methods: We analyzed a single cell RNA-seq (scRNA-seq) dataset of human GC tissues to identify the cell types expressing AXL. Human CAFs and mouse gastric fibroblasts (MGF) expressing AXL were treated with AXL inhibitors, such as CCB3233 and 9im. Additionally, AXL knockdown (KD) was performed in CAFs and MGFs, which were subsequently co-cultured with human GC cell lines (SNU668 or MKN-1) or mouse GC cell lines (ACKPY4113) to assess the effects of AXL+ fibroblasts on GC progression. The impact of AXL-inhibited fibroblasts on T-lymphocytes or macrophages was also evaluated. Furthermore, transcriptome analysis was conducted on AXL KD and control fibroblasts. Results: The analysis using scRNA-seq dataset revealed that AXL expression was predominantly upregulated in CAFs compared to other cell types. High expression and activation of AXL in fibroblasts were confirmed across various cell lines, including GC cell lines, fibroblasts and immune cells. AXL inhibitors, such as CCB3233 and 9im, effectively reduced AXL phosphorylation in human CAFs and MGFs. Co-culture experiments demonstrated that AXL-inhibited or KD fibroblasts significantly reduced the migration or invasion of GC cells compared to control fibroblasts. Moreover, while control CAFs and MGFs suppressed the activation of T- lymphocytes or macrophages, AXL-inactivated or KD fibroblasts were unable to inhibit immune cell activation. Transcriptome analysis of AXL KD or control fibroblasts revealed reduced expression of chemokines such as CXCL9 and CXCL13, which may explain the observed experimental results. Conclusions: Our findings highlight the crucial role of AXL-positive fibroblasts in promoting the aggressive phenotype of GC cells and suppressing immune cell activity in the GC TME. Targeting AXL in CAFs holds significant promise as a novel therapeutic strategy for GC treatment. Citation Format: Tuyen Thanh Tran, Yulim Lee, In-Hye Ham, Hur Hoon. AXL-positive cancer-associated fibroblasts enhance the metastatic potential of cancer cells and suppress tumor immunity in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2700.

Background: Cancer-associated fibroblasts (CAFs) are the most prominent cellular components in gastric cancer (GC) stroma that contribute to GC progression, treatment resistance, and immunosuppression. This study aimed at exploring stromal CAF-related factors and developing a CAF-related classifier for predicting prognosis and therapeutic effects in GC.Methods: We downloaded mRNA expression and clinical information of 431 GC samples from Gene Expression Omnibus (GEO) and 330 GC samples from The Cancer Genome Atlas (TCGA) databases. CAF infiltrations were quantified by the estimate the proportion of immune and cancer cells (EPIC) method, and stromal scores were calculated via the Estimation of STromal and Immune cells in MAlignant Tumors using Expression data (ESTIMATE) algorithm. Stromal CAF-related genes were identified by weighted gene co-expression network analysis (WGCNA). A CAF risk signature was then developed using the univariate and least absolute shrinkage and selection operator method (LASSO) Cox regression model. We applied the Spearman test to determine the correlation among CAF risk score, CAF markers, and CAF infiltrations (estimated via EPIC, xCell, microenvironment cell populations-counter (MCP-counter), and Tumor Immune Dysfunction and Exclusion (TIDE) algorithms). The TIDE algorithm was further used to assess immunotherapy response. Gene set enrichment analysis (GSEA) was applied to clarify the molecular mechanisms.Results: The 4-gene (COL8A1, SPOCK1, AEBP1, and TIMP2) prognostic CAF model was constructed. GC patients were classified into high– and low–CAF-risk groups in accordance with their median CAF risk score, and patients in the high–CAF-risk group had significant worse prognosis. Spearman correlation analyses revealed the CAF risk score was strongly and positively correlated with stromal and CAF infiltrations, and the four model genes also exhibited positive correlations with CAF markers. Furthermore, TIDE analysis revealed high–CAF-risk patients were less likely to respond to immunotherapy. GSEA revealed that epithelial–mesenchymal transition (EMT), TGF-β signaling, hypoxia, and angiogenesis gene sets were significantly enriched in high–CAF-risk group patients.Conclusion: The present four-gene prognostic CAF signature was not only reliable for predicting prognosis but also competent to estimate clinical immunotherapy response for GC patients, which might provide significant clinical implications for guiding tailored anti-CAF therapy in combination with immunotherapy for GC patients.

Purpose: Gastric cancer (GC) is an aggressive cancer metastasizing with a high propensity for peritoneal dissemination and liver metastasis. Some studies have been shown that not only cancer cells but also their surrounding stroma, especially cancer-associated fibroblasts (CAFs) play an important role in tumor development. Previously, we reported that CXCL12-CXCR4 and integrin β1 signal activation by CAFs co-operates for promoting FAK phosphorylation and enhances the invasiveness of GC cells in extracellular matrix (ECM).On the other hand, a previous study presented that CXCR4 and integrin signaling co-operates in mediating adhesion and chemoresistance in small cell lung cancer cells. Therefore, we hypothesized that CXCL12-CXCR4 and integrin signal activation by CAFs enhances the chemoresistance in GC as well. The aim of current study is to elucidate the significance of CAFs mediating signal activation for chemoresistance in GCs. Experimental Design: We first performed chemo-sensitive assays using GC cells cultured with fresh medium or with CAF-conditioned-medium (CM), and these experiments were conducted on non-coated and Matrigel-coated plates. Next, we examined the CXCL12-CXCR4 and integrin related signaling by western blotting analysis. Furthermore, we investigated the critical molecule for chemoresistance using silencing CXCR4 or integrin β1 in GC cells. Results: Chemo-sensitive assays revealed that GC cells cultured with CAF-CM showed more resistant to cisplatin and reactive oxygen spices (ROS) than those cultured with fresh medium. Moreover, GC cells with CAF-CM on Matrigel-coated plates exhibited remarkable resistance in these assays. On the other hand, western blotting analysis showed that Akt activity in GC cells cultured with CAF-CM was up-regulated in concurrence with FAK phosphorylation. Finally, the chemoresitance induced by CAFs was significantly suppressed by CXCR4 or integrin β1 silencing. Conclusions: These results suggest that CXCL12/CXCR4 and integrinβ1 signal activation by CAFs promoted the chemoresistance through enhancing their interaction with ECM in GC. This mechanism underlying the chemoresistance may provide a novel therapeutic target in advanced GCs. Citation Format: Yuka Tamaoki, Takatsugu Ishimoto, Keisuke Miyake, Daisuke Izumi, Daisuke Kuroda, Tsugio Eto, Kota Arima, Hironobu Shigaki, Junji Kurashige, Masaaki Iwatsuki, Yoshifumi Baba, Yasuo Sakamoto, Naoya Yoshida, Hideo Baba. CXCL12/CXCR4 and integrin signal activation by cancer-associated fibroblasts enhances the chemoresistance in gastric cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5113.

BackgroundThe prognosis of patients with advanced gastric cancer (GC) remains unsatisfactory owing to distant metastasis and resistance to concurrent systemic therapy. Cancer-associated fibroblasts (CAFs), as essential participators in the tumor microenvironment (TME), play a vital role in tumor progression. Thus, CAFs-targeting therapy is appealing for remodeling TME and sensitizing GC to conventional systemic therapy.MethodsAmphiphilic SN38 prodrug polymeric micelles (PSN38) and encapsulated the hydrophobic esterase-responsive prodrug of Triptolide (TPL), triptolide-naphthalene sulfonamide (TPL-nsa), were synthesized to form PSN38@TPL-nsa nanoparticles. Then, CAFs were isolated from fresh GC tissues and immortalized. TPL at low dose concentration was used to investigate its effect on CAFs and CAFs-induced GC cells proliferation and migration. The synergistic mechanism and antitumor efficiency of SN38 and TPL co-delivery nanoparticle were investigated both in vitro and in vivo.ResultsFibroblast activation protein (FAP), a marker of CAFs, was highly expressed in GC tissues and indicated poorer prognosis. TPL significantly reduced CAFs activity and inhibited CAFs-induced proliferation, migration and chemotherapy resistance of GC cells. In addition, TPL sensitized GC cells to SN38 treatment through attenuated NF-κB activation in both CAFs and GC cells. PSN38@TPL-nsa treatment reduced the expression of collagen, FAP, and α-smooth muscle actin (α-SMA) in tumors. Potent inhibition of primary tumor growth and vigorous anti-metastasis effect were observed after systemic administration of PSN38@TPL-nsa to CAFs-rich peritoneal disseminated tumor and patient-derived xenograft (PDX) model of GC.ConclusionTPL suppressed CAFs activity and CAFs-induced cell proliferation, migration and chemotherapy resistance to SN38 of GC. CAFs-targeted TPL and SN38 co-delivery nanoparticles exhibited potent efficacy of antitumor and reshaping TME, which was a promising strategy to treat advanced GC.Graphical

The effects of cancer-associated fibroblasts (CAF) on the progression of gastric carcinoma (GC) has recently been demonstrated. However, agents targeting the interaction between CAF and GC cells have not been applied in a clinical setting. Here, we examined if inhibition for Axl receptor tyrosine kinase (AXL) can suppress CAF-induced aggressive phenotype in GC. We investigated the function of CAF-derived growth arrest-specific 6 (GAS6), a major ligand of AXL, on the migration and proliferation of GC cells. The effect of the AXL inhibitor, BGB324, on the CAF-induced aggressive phenotype of GC cells was also investigated. In addition, we performed immunohistochemistry to examine the expression of phosphorylated AXL protein in 175 GC tissues and evaluated its correlation with the prognosis. The qPCR and western blot analysis showed that GAS6 expression was higher in CAF relative to other cells. We found that co-culture with CAF increased the phosphorylation of AXL (P-AXL), differentiation into a mesenchymal-like phenotype, and cell survival in GC cell lines. When the expression of AXL was genetically inhibited in GC cells, the effect of CAF was reduced. BGB324, a small molecule inhibitor of AXL, suppressed the effects of CAF on GC cell lines. In GC tissues, high levels of P-AXL were significantly associated with poor overall survival (P = 0.022). We concluded that CAF are a major source of GAS6 and that GAS6 promotes an aggressiveness through AXL activation in GC. We suggested that an AXL inhibitor may be a novel agent for GC treatment.

Calponin 1 increases cancer-associated fibroblasts-mediated matrix stiffness to promote chemoresistance in gastric cancer

Cancer-associated fibroblasts (CAFs), as the activated stroma cells, contribute to tumor progression via the release of cytokines, growth factors, and hormones. However, neither the factors produced by CAFs nor the molecular mechanisms were illuminated very well in gastric cancer (GC). Immunohistochemical staining of alpha-smooth muscle actin (α-SMA) was applied to examine the number of CAFs in GC samples from 227 patients. ELISA and qRT-PCR were performed to detect the expression of interleukin 17a (IL-17a). The migration and invasion of GC cells were determined by the Transwell assay. The expressions of JAK2, STAT3, MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured by western blotting. IL-17a was blocked with a polyclonal antibody, and JAK2/STAT3 signaling pathway was blocked by a specific inhibitor AG490. High CAFs in GC tissues were positively correlated with advanced TNM stage and perineural invasion. Furthermore, GC patients with high CAFs in tumor tissues had an obvious worse disease-free survival (DFS) and disease-special survival (DSS). Multivariate analysis showed that high CAFs in GC tissues were an independent risk factor for DFS and DSS. CAFs expressed IL-17a significantly after GC cell co-culture. CAFs markedly enhanced the migration and invasion abilities of AGS and SGC-7901 cells. Moreover, CAFs co-culture resulted in increased levels of MMP2/9, reduced expressions of TIMP1/2, and activation of the JAK2/STAT3 signaling pathway in the GC cells. IL-17a neutralizing antibody or JAK2 inhibitor AG490 can significantly inhibit the effects of CAFs on the migration, invasion, MMP2/9, TIMP1/2, and JAK2/STAT3 pathways of GC cells. CAFs correlated with unfavorable clinical features and poor prognosis of GC patients. CAFs secreted IL-17a, which promoted the migration and invasion of GC cells through activating JAK2/STAT3 signaling. These results may identify IL-17a as a promising prognostic marker and therapeutic target of GC.

Purpose: Gastric cancer (GC) is the fourth most commonly diagnosed cancer and the third leading cause of cancer mortality worldwide. The range of therapeutic strategies available for the treatment of GC has improved in recent decades. However, the prognosis of patients with advanced GC remains poor even after curative resection, mainly because of recurrence, such as peritoneal dissemination and liver metastases. Previous studies have shown that the interaction between cancer cells and their surrounding stroma plays an important role in tumor development. Cancer-associated fibroblasts (CAFs) have been reported to be involved in invasion and metastasis in cancers, including gastric cancer (GC), via their stimulation of CXCL12/CXCR4 signaling. However, the mechanisms underlying the tumor-promoting effects and the potential of developing therapeutic targets using CXCL12/CXCR4 signaling activated by CAFs are not fully understood. Experimental Design: We first analyzed CXCL12 expression in resected GC tissues of 110 patients by immunohistochemistry (IHC). We next established primary normal fibroblasts (NFs) and CAFs from GC tissues and examined the functional differences between these primary fibroblasts using co-culture assays with GC cell lines. Furthermore, we evaluated the efficacy of a CXCR4 antagonist (AMD3100) and a FAK inhibitor (PF-573,228) on the invasive ability of GC cells. Results: We determined that high CXCL12 expression was significantly associated with larger tumor size, deeper tumor depth, lymphatic invasion and poor prognosis in GC. We established new primary CAFs and their adjacent NFs from resected stomach tissue in GC patients. We evaluated the change in mobility during the direct co-culture of GC cells and fibroblasts using real-time imaging. The motility of GC cells significantly increased upon direct co-culture with CAFs more than it did in cells with NFs compared with control RPMI during observation for 24 hours. The motility of GC cells with CAFs was effectively suppressed by AMD 3100 compared to GC cells with NFs. CXCL12/CXCR4 activation by CAFs mediated the clustering of integrin β1 on the cell surface and promoted the invasive ability of GC cells. Notably, AMD3100 was more efficient at inhibiting GC cell invasion through the suppression of integrin β1/FAK signaling compared with PF-573,228. Conclusions: These results suggest that CXCL12 derived from CAFs promotes invasive ability by enhancing the clustering of integrin β1 in GC cells and results in GC progression. The current data provide evidence that CXCL12/CXCR4 inhibition by AMD3100 is more efficient in suppressing GC cell invasion by not only inhibiting intracellular signaling but also by attenuating the interaction between cancer cells and the extracellular matrix compared with PF-573,228. Our present study represents the rationale for establishing a therapeutic strategy targeting CXCL12/CXCR4 signaling. Citation Format: Daisuke Izumi, Takatsugu Ishimoto, Hidetaka Sugihara, Eto Kojiro, Hiroshi Sawayama, Keisuke Miyake, Yuki Kiyozumi, Keisuke Kosumi, Ryuma Tokunaga, Kazuto Harada, Junji Kurashige, Masaaki Iwatsuki, Shiro Iwagami, Yoshifumi Baba, Yasuo Sakamoto, Yuji Miyamoto, Naoya Yoshida, Masayuki Watanabe, Hideo Baba. CXCL12/CXCR4 activation by cancer-associated fibroblasts promotes integrin β1 clustering and invasive ability in gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 423. doi:10.1158/1538-7445.AM2015-423

Background: Gastric cancer (GC) is one of the most common and lethal cancers and the prognosis of GC patients remains very poor. Cancer-associated fibroblasts (CAFs) largely facilitate the progression of GC but the underlying molecular mechanisms remain elusive despite numerous studies. Here, we investigated the role of CLIC1 in CAF activation and GC. Methods: qRT-PCR and western blot were performed to determine expression levels of cytokines, transcription factors and related proteins such as CAF markers. MTT assay was used to examine the proliferation of GC cells while transwell assay and tumorsphere formation assay were done to measure the migration, invasion and stemness of GC cells. Conditioned medium model was used to examine the intercellular communication between CAFs and GC cells. Results: Overexpression of CLIC1 in fibroblasts induced CAF activation and enhanced cell proliferation and migration. Also, CLIC1 up-regulated integrins/NF-κB signaling in CAFs. CLIC1-overexpressed fibroblasts promoted proliferation and migration of GC cells and up-regulated cancer stem cell markers and promoted EMT program of GC cells. IL-6 and IL-8 neutralizing antibodies inhibit the pro-tumor effects of CLIC1-overexpressing fibroblasts on GC cells. Further, knockdown CLIC1 in GC cells suppressed activation of CAF. Conclusions: CLIC1 overexpression activates CAF via up-regulating integrins/NF-κB signaling and activated CAF releases IL-6 and IL-8 to promote multiple malignant phenotypes of GC cells. These results implicate an essential role of CLIC1 in CAF activation and GC progression, which suggests that CLIC1 could serve as a potential target for GC therapy.

TRIM26 as a dual regulator of ferroptosis and chemoresistance in gastric cancer through HSF1 ubiquitination and exosomal miR-24-3p signaling.

Cancer-associated fibroblasts (CAF) are a major component of tumor stroma and their effect on the progression of gastric carcinoma (GC) has recently been demonstrated. However, agents targeting the interaction between CAF and GC cells have not been applied in a clinical setting. The aim of this study was to investigate the effect of an AXL inhibitor on CAF-induced GC progression. We examined growth arrest specific factor 6 (GAS6) expression and phosphorylation of AXL in various cell lines, including GC cells and non-cancerous cells, by qPCR, western blot, and immunocytochemistry. We investigated the role of CAF-derived GAS6 on the migration and proliferation of GC cells using migration and cell survival assays. The effect of the AXL inhibitor, Bemcentinib, on the CAF-induced aggressive phenotype of GC cells was also investigated. Finally, we performed immunohistochemistry to measure the phosphorylation of AXL in a tissue microarray composed of 175 GC tissues, and evaluated its correlation with the prognosis of GC patients. qPCR and western blot analysis showed that GAS6 expression was higher in CAF relative to other cells. We found that CAF increased the phosphorylation of AXL (P-AXL), differentiation into a mesenchymal-like phenotype, and cell survival in GC cell lines. When the expression of AXL was inhibited in GC cells, the effect of CAF was reduced. In addition, Bemcentinib, a small molecule inhibitor of AXL, suppressed the effects of CAF on GC cell lines. In GC tissues, P-AXL positively correlated with the expression of vimentin (P &amp;lt; 0.001) and high levels of P-AXL were significantly associated with poor overall survival (P = 0.022).These findings suggest that CAF is a major source of GAS6 in the GC microenvironment and actively promotes an aggressive phenotype in GC cells through AXL activation. We conclude that an AXL inhibitor may be a novel agent for GC treatment. Citation Format: Dagyoeng Lee, Jongsu Woo, Cheong A Bae, In-Hye Ham, Hye Jung Oh, Sang-Yong Son, Sang-Uk Han, Tae-Min Kim, Jung Hwan Yoon, Won Sang Park, Hoon Hur. Inhibiting the GAS6/AXL axis suppresses tumor progression by blocking the interaction between cancer-associated fibroblasts and cancer cells in gastric carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2030.

Background: The protumor activities of cancer-associated fibroblasts (CAFs) suggest that they are potential therapeutic targets for the treatment of cancer. The mechanism of CAF heterogeneity in gastric cancer (GC) remains unclear and has slowed translational advances in targeting CAFs. Therefore, a comprehensive understanding of the classification, function, activation stage, and spatial distribution of the CAF subsets in GC is urgently needed.Methods: In this study, the characteristics of the CAF subsets and the dynamic communication among the tumor microenvironment (TME) components regulated by the CAF subsets were analyzed by performing single-cell RNA sequencing of eight pairs of GC and adjacent mucosal (AM) samples. The spatial distribution of the CAF subsets in different Lauren subtypes of GC, as well as the neighborhood relations between these CAF subsets and the protumor immune cell subsets were evaluated by performing multistaining registration.Results: Tumor epithelial cells exhibited significant intratumor and intertumor variabilities, while CAFs mainly exhibited intratumor variability. Moreover, we identified four CAF subsets with different properties in GC. These four CAF subsets shared similar properties with their resident fibroblast counterparts in the adjacent mucosa but also exhibited enhanced protumor activities. Additionally, two CAF subsets, inflammatory CAFs (iCAFs) and extracellular matrix CAFs (eCAFs), communicated with adjacent immune cell subsets in the GC TME. iCAFs interacted with T cells by secreting interleukin (IL)-6 and C-X-C motif chemokine ligand 12 (CXCL12), while eCAFs correlated with M2 macrophages via the expression of periostin (POSTN). eCAFs, which function as a pro-invasive CAF subset, decreased the overall survival time of patients with GC.Conclusions: iCAFs and eCAFs not only exhibited enhanced pro-invasive activities but also mobilized the surrounding immune cells to construct a tumor-favorable microenvironment. Therefore, inhibiting their activation restrains the GC 'seed' and simultaneously improves the 'GC' soil, suggesting that it represents a promising therapeutic strategy for the treatment of GC.

The present study aimed to investigate whether the Janus-activated kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling pathway is a critical mechanism underlying the cancer-associated fibroblast (CAF)-induced chemoresistance of gastric cancer (GC). In addition, the present study tried to suggest a natural product to compromise the effects of CAF on the chemoresistance of GC. The results of cell proliferation assay revealed that the conditioned medium (CM) collected from CAFs further increased resistance to 5-fluorouracil (5-FU) in GC cell lines. Secretome analysis revealed that the levels of several secreted proteins, including C-C motif chemokine ligand 2, C-X-C motif chemokine ligand 1, interleukin (IL)-6 and IL-8, were increased in the CM from CAFs co-cultured with cancer cells compared to CM from cancer cells. Western blot analysis revealed that CAFs activated the JAK/STAT3 signaling pathway in cancer cells. The experimental models revealed that curcumin abrogated the CAF-mediated activation of the JAK/STAT3 signaling pathway in GC cells. In vivo data revealed the synergistic effects of curcumin with 5-FU treatment in xenograft GC tumors. These data strongly suggest that the suppression of the JAK/STAT3 signaling pathway counteracts the CAF-induced chemoresistance of GC cells. It is suggested that curcumin may be a suitable natural product which may be used to overcome chemoresistance by inhibiting the CAF-induced activation of the JAK/STAT3 signaling pathway in GC.

Background: Cancer-associated fibroblasts (CAFs) are principal constituents of the tumor microenvironment (TME) and play a critical role in tumor progression. The CXCL12/CXCR4 axis regulates multiple facets of the TME. The aim of this study was to determine the relationship between CXCL12 expression in CAFs and the malignant progression of gastric cancer (GC).Methods: In the GEO (Gene Expression Omnibus) database, we performed transcriptome analysis on paired gastric cancer RNA sequencing samples, and scRNA analysis was performed on advanced malignant GC samples from the scRNA sequencing data set. Fibroblast cells were co-cultured with GC cells, and invasion, migration, epithelial-mesenchymal transformation (EMT) were determined. After blocking the expression of fibroblast CXCL12, cells were co-cultured with a GC cell line. Detection of GC cell line invasion, migration, EMT and CXCR4, Wnt5a and β-Catenin expression levels was performed. Primary CAFs and gastric normal fibroblasts were isolated and CXCL12 mRNA and protein expression were determined. In addition, a cohort of 285 GC cases was established, protein expression was evaluated immunohistochemically, and prognostic results were analyzed.Results: GC transcriptome analysis suggested that cytokine-cytokine receptor interaction and the Wnt signaling pathway in GC tissues were significantly up-regulated. scRNA analysis of advanced malignant GC samples showed that severe intestinal metaplasia (SIM) in GC specimens of different malignant grades had obvious fibroblast clusters compared to non-atrophic gastritis (NAG) and early gastric cancer (EGC). In the SIM group, fibroblast cluster, CXCL12, CXCR4, and Wnt5a were overexpressed. Co-culturing with fibroblast cells significantly increased the invasion, migration, and EMT of GC cells, and blocking CXCL12 in CAFs disturbed the expression of Wnt5a and β-catenin. In our cohort of GC patients, high CXCL12 expression in CAFs significantly correlated with histological grade (P = 0.012) and TNM stage (P = 0.014), as well as with poor overall survival (p = 0.0107).Conclusion: High expression of CXCL12 in CAFs in a GC microenvironment can affect the migration, invasion, and EMT of GC cells. Furthermore, it can cause poor prognosis in patients with GC.