Activation of Phospho Signaling Pathways in Human Colorectal Cell Lines in Response to Cytokines

Abstract

Abstract Colorectal carcinoma (CRC) tumors are classified in two groups: approximately 75% of patients have CRC tumors of sporadic origin and 25 % of patients have a hereditary contribution. Understanding the underlying molecular mechanisms is a prerequisite for developing therapeutic strategies. We investigated cytokine‐induced changes of the JAK‐STAT signaling pathways in several CRC ell lines.Methods Human colorectal cell lines (HCT‐15, Colo 205, LS ‐180, SW480 and SW620) were used to study modulation of MHC class I and class II expression in response to human recombinant interferon alpha and interferon gamma. The nuclear translocation of STAT proteins was analyzed by confocal laser microscopy and flow cytometry.Results We have observed that several colon carcinoma cell lines do not express MHC proteins. Strong activation of STAT1 was observed in response to interferon gamma. Human recombinant IL‐6 and IL‐4 activated STAT3 and STAT6, respectively. Confocal microscopy identified the nuclear translocation of the STAT proteins.Conclusions Our data demonstrate the up‐regulation of the members of the JAK‐STAT signaling pathway in colon carcinoma cell lines.