Basic Research In Function And Mechanism-of-action Of Interlukin-33 In Outgrowth Of Human Lung Cancer

Objective:Lung cancer is the leading cause of cancer-related death worldwide.The incidence of lung cancer patients increases every year.Due to the lack of efficient therapeutics,the mortality of lung cancer patients is high and the prognosis is far less satisfied.Uncontrolled outgrowth is one feature of lung cancer cells and an important marker to evaluate the treatment efficiency.However,crucial factors underlie outgrowth of lung cancer cells and the related action-of-mechanisms are unclear.Investigations on driving forces behind the outgrowth capacity of lung cancer cells are urgently needed for understanding of lung cancer pathogenesis and valuable for novel therapeutic explorations.Herein,we investigated the function and underlying mechanisms of IL-33 in outgrowth of lung cancer cells from clinical patients.Methods:Purification of tumor cells was performed by human tumor cell isolation kit.Cell transfection was achieved by Lonza transfection kit and the efficiency was determined by qPCR and flow cytometry.Outgrowth of cancer cells was analyzed with MTT assay and humanized immuno-deficient mice.IL-33,ST2 and Glucose transporter 1(GLUT 1)was determined by qPCR,immunohistochemistry or flow cytometry.Uptake of glucose and production of lactate were determined with the commercial kits.Results:Expressions of IL-33 and its receptor ST2 in tumor tissues were significantly higher than that in adjacent tissues.IL-33 and ST2 expressions predicted advanced TNM stages of lung cancer patients.Of note,expressions of IL-33 and ST2 were significantly higher in poorly-differentiate lung cancer.IL-33 overexpression by transfection with human IL-33 expression vector enhanced outgrowth of human lung cancer cells.Down-regulation of IL-33 expression by transfection with human IL-33 shRNA restricted outgrowth of human lung cancer cells.Stimulation with recombinant human IL-33 protein promoted the outgrowth of lung cancer cells.The effect of IL-33 on tumor outgrowth could be further enhanced by ST2 overexpression and blocked by ST2 knockdown in lung cancer cells.Likewise,administration of ST2 neutralizing antibody abrogated IL-33-mediated outgrowth of human lung cancer cells.Mechanistically,IL-33/ST2 signaling contributed to outgrowth of human lung cancer cells by inducing membrane localization of GLUT1,promoting glucose uptake and glycolysis of human lung cancer cells.Accordingly,genetic knockdown of GLUT1 efficiently limited the function of IL-33 in facilitating outgrowth of human lung cancer cells.Conclusion:IL-33 is an important pro-cancer element in progression of human lung cancer.Specifically,IL-33 maintains and enhances the outgrowth of human lung cancer cells through ST2 recognition.By binding to ST2 receptor,IL-33 signal fuels glycolysis of human lung cancer via promoting their membrane localization of GLUT1 protein and increasing their capacity of glucose uptake,providing necessary energy for the outgrowth of lung cancer cells.Interventions in IL-33/ST2 signaling would be helpful in clinical practice for controlling the outgrowth of human lung cancer.These findings could not only further our understanding of human lung cancer pathogenesis,but also facilitate the development of novel treatment options for lung cancer patients.