OncoTargets and Therapy (May 2020)
Six1 Overexpression Promotes Glucose Metabolism and Invasion Through Regulation of GLUT3, MMP2 and Snail in Thyroid Cancer Cells
Abstract
Chuanjia Yang,1 Weixue Xu,1 Jian Gong,2 Fang Chai,3 Dongxu Cui,1 Zhen Liu1 1Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, People’s Republic of China; 2Department of Clinical Pharmacy, School of Life Science and Pharmaceutical University, Shenyang, People’s Republic of China; 3Department of Thyroid Surgery, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, People’s Republic of ChinaCorrespondence: Chuanjia Yang; Zhen LiuDepartment of General Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, People’s Republic of ChinaEmail [email protected]; [email protected]: Sineoculis homeobox homolog 1 (Six1) overexpression has been implicated in several human cancers. To date, its clinical significance and potential function in human thyroid cancer remain unclear.Methods: Immunohistochemistry was used to examine the protein expression of BCAT1 in 89 cases of thyroid cancer tissues. We overexpressed and knockdown Six1 in TPC-1 and B-CPAP thyroid cancer cell lines. Biological roles and potential mechanisms of Six1 were examined using CCK-8, colony formation assay, Matrigel invasion assay, Western blot, PCR, ATP assay, and 2-NBDG uptake assay.Results: We showed that Six1 protein was upregulated in thyroid cancers and was associated with tumor size and nodal metastasis. Analysis of TCGA dataset indicated that Six1 mRNA was higher in thyroid cancers compared with normal thyroid. CCK-8, colony formation and Matrigel invasion assays demonstrated that Six1 overexpression promoted proliferation, colony number and invasion while Six1 siRNA knockdown inhibited the growth rate, colony formation ability and invasive ability in both cell lines. Notably, Six1 upregulated glucose consumption, lactate production level and ATP level. 2-NBDG uptake analysis showed that Six1 overexpression upregulated glucose uptake while Six1 knockdown inhibited glucose uptake. Further analysis revealed that Six1 overexpression upregulated Snail, MMP2 and GLUT3 at both mRNA and protein levels. TCGA analysis demonstrated positive associations between Six1 and Snail, MMP2 and GLUT3 at the mRNA levels.Conclusion: Taken together, our data demonstrated that Six1 was upregulated in human thyroid cancers and promoted cell proliferation and invasion. Our data also revealed new roles of Six1 in thyroid cancer development by modulating glucose metabolism and invasion, possibly through regulation of Snail, MMP2 and GLUT3.Keywords: Six1, thyroid cancer, glucose metabolism, GLUT3
