SOX30, a valuable diagnostic marker, suppresses tumor growth via inducing autophagy as key cadres in ovarian cancer

Background: Discovering and identifying novel diagnostic markers and effective therapeutic targets for ovarian cancer is urgently required. SOX30 has recently been demonstrated to suppress tumor metastasis and represent prognostic and chemotherapeutic marker for advanced-stage ovarian cancer. We aim to investigate the expression pattern, expression regulation, and diagnostic value of SOX30, as well as determining the role of SOX30 on tumor growth and the corresponding mechanism in ovarian cancer. Methods Using The Cancer Genome Atlas database, the association between the expression levels of SOX30 with copy number variation and DNA methylation in ovarian cancer were comprehensively analyzed. The function of SOX30 in tumor growth was studied by MTS assay, colony formation assay, rescue assay, and xenograft models. Flow cytometry, western blotting, and confocal microscopy were used to investigate the role of SOX30 on apoptosis and autophagy. Genes co-expressed with SOX30 were analyzed, and functional enrichment analysis was performed. Results SOX30 was frequently overexpressed which was closely associated with its copy number amplification, and the aberrant expression of SOX30 could clearly discriminate tumor from normal tissues very well in ovarian cancer. Functionally, SOX30 led to significant inhibition of cancer cell proliferation in vitro, and tumor growth in vivo with induction of slight cell apoptosis but apparent cell autophagy in ovarian cancer. The inhibition of SOX30 on cancer cell proliferation is dependent on regulation of autophagy. At the molecular level, SOX30 could regulate biological processes and signaling pathway of autophagy rather than of apoptosis in ovarian cancer. Moreover, SOX30 was indeed positively correlated with various autophagic key genes in ovarian cancer. Conclusions The findings provide a new diagnostic marker and promising therapeutic target, and highlight unappreciated roles of SOX30 on cancer cell proliferation and tumor growth mainly through an autophagic mechanism in ovarian cancer.