TMCO1通过激活IKBKE/NF-κB轴驱动结肠癌细胞生长和转移OA

AIM:We investigated the specific functions and molecular mechanisms of transmembrane and coiled-coil domains 1(TMCO1)in colon cancer progression,focusing on the molecular mechanism by which TMCO1 regu-lates the inhibitor of nuclear factor-κB kinase subunit epsilon(IKBKE)/nuclear factor-κB(NF-κB)signaling to influence cancer cell growth and metastasis.METHODS:Cancer and adjacent paracancerous tissues were collected from 48 pa-tients with moderately to poorly differentiated colon cancer,and TMCO1 and IKBKE positive expression levels were detect-ed by immunohistochemistry.SW480 cells with high TMCO1 expression and HCT-116 cells with low TMCO1 expression were selected.TMCO1 knockdown(shRNA-TMCO1),overexpression(OE-TMCO1),and empty vector(shRNA-NC or OE-NC)cell models were constructed using SW480 and HCT-116 cells.For rescue experiments,IKBKE was knocked down in OE-TMCO1 cells(OE-TMCO1+siRNA-IKBKE group),alongside OE-NC,OE-TMCO1,siRNA-NC,and siRNA-IKBKE groups.For endoplasmic reticulum(ER)stress intervention,TMCO1-knockdown cells were treated with the ER stress inhibitor 4-phenylbutyric acid(4-PBA;shRNA-TMCO1+4-PBA group),alongside shRNA-TMCO1 and shRNA-NC groups.Transcriptome sequencing was performed to identify differentially expressed genes and key signaling pathways.RT-qPCR and Western blot were performed to detect mRNA and protein expression,respectively.Cell proliferation was assessed by colony formation assay,cell migration was evaluated by Transwell assay and cell apoptosis was detected by flow cytometry.The ER probes and calcium ion fluorescent probes,Fluo-4 AM and Fura-2 AM,were used to measure cal-cium ion concentration.RESULTS:TMCO1 knockdown resulted in differential expression of 1 027 genes.KEGG enrich-ment analysis revealed that these genes were significantly enriched in immune-inflammatory pathways,including NF-κB signaling(P<0.05).Immunohistochemical results showed that the positive expression rates of TMCO1 and IKBKE in co-lon cancer tissues were 66.67%(32/48)and 56.25%(27/48),respectively.RT-qPCR and Western blot results demon-strated that TMCO1 positively regulates IKBKE and NF-κB mRNA and protein expression of(P<0.01).TMCO1 overex-pression promoted cell proliferation,migration(P<0.01)and inhibited apoptosis,while IKBKE knockdown completely abolished these tumor-promoting effects of TMCO1(P<0.01).Via its calcium channel function,TMCO1 maintained ER calcium homeostasis and suppressed ER stress,as evidenced by decreased GRP75,CHOP,and caspase-3 protein levels(P<0.01),thereby regulating the IKBKE/NF-κB signaling axis.Inhibition of ER stress by 4-PBA reversed suppression of the IKBKE/NF-κB pathway induced by TMCO1 knockdown(P<0.01).CONCLUSION:The TMCO1 and IKBKE ex-pression levels were significantly higher in colon cancer tissues than those in adjacent paracancerous tissues.TMCO1 maintains ER calcium homeostasis,thereby positively regulating IKBKE/NF-κB signaling,and ultimately promoting can-cer cell proliferation,migration,and survival,suggesting that TMCO1 may serve as a potential molecular therapeutic tar-get for colon cancer.