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Objective To determine the expression and clinical significance of pseudogene FMO6P in gastric cancer, and explore its functions and underlying molecular mechanism in regulating the invasion and metastasis of gastric cancer cells. Methods The expression level of FMO6P in gastric cancer tissues and cell lines was detected by quantitative real time polymerase chain reaction(qRT-PCR). The migration and invasion abilities of gastric cancer cells were detected by transwell assay. The effect of FMO6P on the tumor formation and peritoneal dissemination of gastric cancer cells were evaluated by injecting FMO6P-overexpressing gastric cancer cells into the subcutaneous or peritoneal cavity of nude mice respectively. The expression levels of epithelial-mesenchymal transition(EMT) markers, including E-cadherin, N-cadherin, ZEB1, MMP2, and the activation of AKT/mTOR pathway in FMO6P-overexpressing or knockdown gastric cancer cells were measured by Western blot. Results The expression of FMO6P was significantly reduced in tumor tissues compared to its adjacent non-tumor tissues of gastric cancer, FMO6P expression level in tumor tissues was correlated with tumor size and TNM stage. Overexpression of FMO6P significantly inhibited the invasion and migration abilities of gastric cancer cells, while downregulation of FMO6P expression promoted the invasion and migration ability of gastric cancer cells. Overexpression of FMO6P in gastric cancer cells significantly inhibited the subcutaneous tumor formation and peritoneal dissemination of gastric cancer cells in nude mice. Moreover, overexpression of FMO6P promoted the expression of E-cadherin, and inhibited the expression of N-cadherin, ZEB1, and MMP2 in gastric cancer cells. The phosphorylation levels of AKT and mTOR were also downregulated in gastric cancer cells overexpressing FMO6P. Conclusion All these findings suggested that pseudogene FMO6P suppresses the invasion and migration potential of gastric cancer cells in vitro and in vivo, which is possibly through the inhibition of the AKT/mTOR signaling pathway.

Background: The ALEX is a novel member of the armadillo family and ALEX1 was reported to be reduced or even lost in multiple solid tumors. However, its expression profile and oncogenic role in gastric cancer (GC) remains largely unknown.Methods: ALEX1 expression was detected in 161 GC samples by immunohistochemistry staining. NCI-N87 cells transfected by ALEX1 lentivirus vectors and MKN28 cells transfected by ALEX1 shRNA were used for biological function investigation. Western blot was applied to explore the molecular mechanism and pull-down assays were applied to measure the activity of Rho GTPases. In vivo tumorigenicity, peritoneal and lung metastasis experiments were performed by tumor cell engraftment into nude mice. Bisulfite genomic sequencing and methylation-specific PCR were applied to check the methylation status of the ALEX1 gene.Results: The expression rate of ALEX1 was significantly reduced in gastric tumor samples compared to non-tumor samples (43.5 vs. 90.2%), and its expression was closely related to the tumor differentiation, TNM staging, and lymph nodes metastasis. ALEX1 overexpression in NCI-N87 cells significantly inhibited cell proliferation, migration, and invasion in vitro, and disrupted the structure of the cytoskeleton. ALEX1 overexpression attenuated xenografts growth, peritoneal, and lung metastasis in nude mice. Mechanistically, the overexpression of ALEX1 inhibits thrombin-induced metastasis and Rho GTPases activation. Bisulfite genomic sequencing and methylation-specific PCR revealed that the promoter of ALEX1 is highly methylated in GC cells and tissues.Conclusions: ALEX1 expression is reduced in GC and is involved in diverse cellular functions. ALEX1 inhibits metastasis through the PAR-1/Rho GTPase signaling pathway. [ABSTRACT FROM AUTHOR]

Treg-induced immunosuppression is now recognized as a key element in enabling tumors to escape immune-mediated destruction. Although topical TLR7 therapies such as imiquimod have been proved successful in the treatment of dermatological malignancy and a number of conditions beyond the FDA-approved indications, the mechanism behind the effect of TLR7 on effector T cell and Treg cell function in cancer immunosurveillance is still not well understood. Here, we found that Loxoribin, one of the TLR7 ligands, could inhibit tumor growth in xenograft models of colon cancer and lung cancer, and these anti-tumor effects of Loxoribin were mediated by promoting CD4⁺T cell proliferation and reversing Treg-mediated suppression via dendritic cells (DCs). However, deprivation of IL-6 using a neutralizing antibody abrogated the ability of Loxoribin-treated DCs, which reversed the Treg cell-mediated suppression. Furthermore, adoptive transfer of Loxoribin-treated DCs inhibited the tumor growth in vivo. Thus, this study links TLR7 signaling to the functional control of effector T cells and Treg cells and identifies Loxoribin as a new therapeutic strategy in cancer treatment, which may offer new opportunities to improve the outcome of cancer immunotherapy.