The Relationship And Mechanism Between IL-33and Chemosensitivity In Gastric Cancer Cell

ObjectiveGastric cancer, with high morbidity and mortality, is one of the most common gastrointestinalcancer in China. Standard treatment for patients with gastric cancer is surgery combined withradiotherapy and chemotherapy. The prognosis is poor because of most patients were diagnosed inadvanced stage (stage III/IV). Accordingly, the neoadjuvant chemotherapy attracts many expertsworldwide, and became a routine therapy for gastric cancer patients. Interleukin-33(IL-33) isnewly discovered cytokine, and its receptor ST2is widely expressed. IL-33is a dual-functionprotein that might act both as a cytokine and as an intracellular nuclear factor. IL-33tethers tochromatin by docking into the acidic pocket at the surface of the nucleosome. Recent studiesshowed that the concentration of serum IL-33in gastric cancer patients is significantly higher thanthat in healthy volunteers, and it is relevant to survival rate. Therefore, the purpose of this study isto determine whether IL-33has effect on chemosensitivity in gastric cancer cell; to reveal its initialmechanism; and to provide a theoretical basis for clinical personalized chemotherapy.Methods1. Immunocytochemistry was used to detect the expression of ST2on MGC-803cellmembrane.2. MGC-803is treated with rhIL-33for24h and CDDP (4 g/ml) for48h. MTT assay wasused to detect the proliferation on cells. Flow cytometry was employed to detect the cell apoptosis.Western blot was used to analyze the expression of caspase-3, respectively.3. MGC-803-IL-33and MGC-803-Mock are infected with Ad-IL-33-EGFP and Ad-EGFP,respectively. Cells are treated with CDDP for48h. MTT assay was used to detect the proliferationon cells. Western blot was employed to analyze the expression of caspase-3and PARP, qRT-PCRwas used to detect the mRNA level of ERCC1and BRCA1, respectively. Results1. IL-33receptor (ST2) is expressed on gastric cancer cell (MGC-803) membrane.2. Gastric cancer cell was treated with rhIL-33and CDDP. The MTT assay and Flowcytometry results showed that there is no significant in cell proliferation and apoptosis. Westernblot results showed that the expression of caspase-3is no significant.3. MGC-803-IL-33MGC-803-Mock and MGC-803ware treated with CDDP. MGC-803-IL-33cells show higher proliferation index than MGC-803-Mock and MGC-803cells (P<0.05).Western blot analysis show down-regulation of caspase-3and PARP activity in MGC-803-IL-33cells compare with control (P<0.05). qRTPCR analysis show the expression of ERCC1mRNA isup-regulated in MGC-803-IL-33cells (P<0.05).ConclusionsICC results show that the expression of ST2on MGC-803cell membrane. And rhIL-33hasno effect on cell chemosensitivity. To increase the expression of IL-33in MGC-803by adenovirusreveals lower chemosensitivity to CDDP. The expression of ERCC1mRNA level is up-regulatedin MGC-803-IL-33. Analysis of these results, we suspect that up-regulation of IL-33coulddiminish sensitivity to chemotherapy by up-regulating of ERCC1gene expression.