Cancer associated fibroblasts-derived SULF1 promotes gastric cancer metastasis and CDDP resistance through the TGFBR3-mediated TGF-ß signaling pathway.

SULF1 has been implicated in a number of malignancies. The function of SULF1 in gastric cancer is disputed. The objective of this study was to examine the role and underlying molecular mechanisms of SULF1 in the context of gastric cancer. We found that the expression of SULF1 was increased in gastric cancer, especially in cancer-associated fibroblasts. The overexpression of SULF1 was found to be significantly correlated with unfavorable prognosis among individuals diagnosed with gastric cancer. Functionally, cancer-associated fibroblasts-derived SULF1 served as a oncogenic molecule which facilitated gastric cancer cells metastasis and CDDP resistance. Mechanistically, SULF1 regulated the communication between gastric cancer cells and cancer-associated fibroblasts in tumor microenvironment as a signaling molecule. Cancer-associated fibroblasts-secreted SULF1 interfered with the interaction between TGF-ß1 and TGFBR3 by combining with TGFBR3 on gastric cancer cell membrane, subsequently activated TGF-ß signaling pathway. In conclusion, our findings have presented novel approaches for potential treatment and prognosis prediction in individuals diagnosed with gastric cancer through the targeting of the CAFs-SULF1-TGFBR3-TGF-ß1 signaling axis.

Unveiling the oncogenic role of CLDN11-secreting fibroblasts in gastric cancer peritoneal metastasis through single-cell sequencing and experimental approaches.

BACKGROUND: Fibroblasts are necessary to the progression of cancer. However, the role of fibroblasts in peritoneal metastasis (PM) of gastric cancer (GC) remains elusive. In this study, we would explore the role of fibroblasts mediated cell interaction in PM of GC. METHODS: Single-cell sequencing data from public database GSE183904 was used to explore the specific fibroblast cluster. Fibroblasts were extracted from PM and GC tissues. The expression level of CXCR7 was verified by western blot, immunohistochemistry. The role of CLDN11 was investigate through in vitro and in vivo study. Multiple immunohistochemistry was used to characterize the tumor microenvironment. RESULTS: CXCR7-positive fibroblasts were significantly enriched in PM of GC. CXCR7 could promote the expression of CLDN11 through activation of the AKT pathway in fibroblasts. Fibroblasts promote the GC proliferation and peritoneal metastasis by secreting CLDN11 in vitro and in vivo. Furthermore, it was revealed that CXCR7-positive fibroblasts were significantly associated with M2-type macrophages infiltration in tissues. CONCLUSION: CXCR7-positive fibroblasts play an essential role in PM of GC via CLDN11. Therapy targeting CXCR7-positive fibroblasts or CLDN11 may be helpful in the treatment of GC with PM.

N6-methyladenosine-modified MIB1 promotes stemness properties and peritoneal metastasis of gastric cancer cells by ubiquitinating DDX3X.

BACKGROUND: Peritoneal metastasis (PM), one of the most typical forms of metastasis in advanced gastric cancer (GC), indicates a poor prognosis. Exploring the potential molecular mechanism of PM is urgently necessary, as it has not been well studied. E3 ubiquitin ligase has been widely established to exert a biological function in various cancers, but its mechanism of action in GC with PM remains unknown. METHODS: The effect of MIB1 on PM of GC was confirmed in vitro and in vivo. Co-immunoprecipitation (Co-IP) and mass spectrometry demonstrated the association between MIB1 and DDX3X. Western blot, flow cytometry and immunofluorescence determined that DDX3X was ubiquitylated by MIB1 and promoted stemness. We further confirmed that METTL3 promoted the up-regulation of MIB1 by RNA immunoprecipitation (RIP), luciferase reporter assay and other experiments. RESULTS: We observed that the E3 ubiquitin ligase Mind bomb 1 (MIB1) was highly expressed in PMs, and patients with PM with high MIB1 expression showed a worse prognosis than those with low MIB1 expression. Mechanistically, our study demonstrated that the E3 ubiquitin ligase MIB1 promoted epithelial-mesenchymal transition (EMT) progression and stemness in GC cells by degrading DDX3X. In addition, METTL3 mediated m6A modification to stabilize MIB1, which required the m6A reader IGF2BP2. CONCLUSIONS: Our study elucidated the specific molecular mechanism by which MIB1 promotes PM of GC, and suggested that targeting the METTL3-MIB1-DDX3X axis may be a promising therapeutic strategy for GC with PM.