PO-041 TNF pathway in metastatic colorectal cancer according to RAS status and implication of potassium channels

IntroductionTumour necrosis factor α (TNF) is a key player in onco-inflammatory context but its implication in the progression of colorectal cancer (CRC) is still controversial. It is equally established that potassium channels contribute to tumour progression but their link to TNF-dependent microenvironment remains poorly described. Our aim is to investigate the effects of TNF on cellular models of colorectal cancer and to identify the potassium channels that could be implicated in the response to TNF.Material and methodsWe analysed the effects of TNF on two CRC cell lines, HCT116 that is KRAS mutated and HT29 that is KRAS wildtype. Cell lines viability and migration were determined by MTT assay and scratch assay, respectively. Cell cycle was examined by propidium iodide DNA staining. Gene expression of TNF pathway and potassium channels was measured by RTqPCR and Western blot.Results and discussionsOur work shows that TNF increased the migration of HT29 cells while reducing that of HCT116. In addition, TNF reduced the viability of HCT116 cells and their colony formation capacity. Moreover, cell cycle analyses showed an increase in the proportion of sub-G1 phase in HCT116 cells after TNF treatment, with no effect on HT29 cells. We also demonstrated an increased expression and phosphorylation of STAT3 protein in HT29 cells, contrary to HCT116 cells that showed reduced phosphorylation following TNF treatment. Interestingly, exogenous TNF increased the transcriptional expression of TNF in both cell lines and this result was associated with an increased expression of its receptor, TNFR2, only in HT29 whereas it was abrogated in HCT116 cells. Furthermore, TNF caused a global decrease in the expression of potassium channels coding genes in HCT116 cells, while this effect was less pronounced in HT29 cells.ConclusionTaken together, our results suggest that the modulation of TNF pathway could be associated to KRAS status. Furthermore, potassium channels could be implicated in CRC cells response to TNF.