These patients were treated by platinumdoublet chemotherapy (carboplatin and paclitaxel or cisplatin and vinorelbine) with concurrent radiotherapy. and CAIX expression in A549 cells in a HIF1dependent manner. Glucose metabolic pathway was shifted from oxidative phosphorylation to glycolysis by inducing HIF1in A549 cells. HIF1 and Oxibendazole CAIX induced chemoresistance under hypoxia, and their inhibition restored the chemosensitivity of A549 cells. The expression levels of HIF1, GLUT1, and CAIX were associated with poor overall survival of lung cancer patients after induction chemoradiotherapy. HIF1 and CAIX affected the chemosensitivity of A549 cells and prognosis of lung cancer patients. Therefore , inhibition of HIF1 and CAIX might improve prognosis of Oxibendazole lung cancer patients after induction chemoradiotherapy. Further analysis might be helpful in developing therapies for lung cancer. Keywords: Carbonic anhydrase IX, chemoresistance, hypoxiainducible element 1, induction chemoradiotherapy, lung cancer == Introduction == Lung cancer is the leading cause of cancer deaths worldwide1. Recently, various therapeutic strategies for lung cancer have been developed; however , these strategies are not adequate for overcoming lung cancer. Patients with earlystage lung cancer are usually treated by surgical resection, which is successful in most cases. On the other hand, patients with advanced lung cancer in many cases are treated using multimodal therapy, including chemotherapy, radiotherapy, and surgical resection. Some studies have provided promising results for the effects of multimodal therapy; however , this therapeutic effectiveness has not been completely evident2. Chemoresistance is an important limitation that hampers the improvement in prognosis of lung cancer patients. Our previous studies have shown that prognosis of patients with advanced nonsmall cell lung cancer (NSCLC), especially stage IIIA NSCLC patients with mediastinal lymph node metastasis, can be increased using multimodal therapy3. However , cancer progression during chemotherapy or relapse after postoperative therapy often occurs most likely because of the induction of chemoresistance through some mechanisms. Hypoxic microenvironment in a malignant solid tumor continues to be reported to be strongly correlated with cancer progression and chemoresistance. Hypoxiainducible element 1 (HIF1), which is a heterodimeric transcription element composed ofandsubunit (HIF1and HIF1, respectively) and whose activity is mainly dependent on the expression levels of the former, is recognized as a key element associated with chemoresistance of lung cancer4, with HIF1induced glycolysis playing an important role in promoting this chemoresistance5. HIF1induced glycolysis exerts many effects on tumor progression and on the mode of energy production5. A recent study showed associations between glycolysis and chemoresistance6. Upregulation of glycolysis increases glucose uptake through glucose transporter 1 (GLUT1)5, a key regulator of glycolysis that has been investigated as a diagnostic tool and therapeutic target for cancer7. Because intracellular Oxibendazole acidosis Oxibendazole is induced by lactate and proton production during glycolysis, the mechanism coping with intracellular acidosis is essential for the maintenance of cellular homeostasis. As a coping mechanism, carbonic anhydrase IX (CAIX), a transmembrane protein neutralizing intracellular acidosis, is induced by HIF1 and is associated with glycolysis in some cancers8. Some studies possess reported the effects of CAIX on prognosis and chemoresistance of patients with different cancers9. However , few studies have reported the effects of CAIX on prognosis and chemoresistance of lung cancer patients. HIF1induced glycolysis is highly associated with cancer progression. Therefore , the investigation of this pathway in lung cancer is important intended for developing novel cancer therapies. The purpose of our study is to elucidate the effects of HIF1and CAIX on chemoresistance Oxibendazole and prognosis of lung cancer patients after induction chemoradiotherapy, and finally to improve them. == Materials and Methods == == Cell culture and reagents == Human being lung adenocarcinoma cellline A549 was obtained from American Type Culture Collection (Manassas, VA) and was cultured in Dulbecco’s modified Eagle’s medium (DMEM; SigmaAldrich, St Rabbit Polyclonal to RRAGB . Louis, MO) that contains 10% fetal bovine serum (FBS). Intended for normoxic experiments, A549 cells were incubated in a wellhumidified incubator with 5% CO2and 95% air at 37C. For hypoxic experiments, A549 cells were incubated with <0. 1% O2in Bactron Anaerobic Chamber, BACLITE2 (Sheldon Manufacturing, Cornelius, OR). HIF1 inhibitor YC1 (Cayman Chemical Company, Ann Arbor, MI) was dissolved in dimethyl sulfoxide at a concentration of 20 mg/mL to prepare a stock answer. Vinorelbine was purchased from WAKO (Osaka, Japan). == Plasmids and transfection == A549 cells were trypsinized, counted, and seeded 1 day before transfection to achieve 70% confluency on the day of making lysates. Smallinterfering RNAs (siRNAs) targetingHIF1were purchased from Invitrogen (Waltham, MA), and siRNAs targetingCAIXand.
