Abstract 1466: Regulation of colon cancer metastasis by sprouty-2

Abstract

Abstract Introduction: We earlier established that sprouty-2 is overexpressed in human colon cancer and up-regulates c-met and thereby increases the growth phenotype and metastatic potential of colon cancer cells (Oncogene, 29: 5241-53, 2010). To our knowledge, this was the first study to demonstrate the tumor oncogene phenotype of sprouty-2 in colon cancer metastasis. On the contrary, cancer protective role of sprouty-2 was noted in breast, liver and prostate cancers. However, a recent report on non-small cell lung cancer (NSCLC) discovered that silencing of sprouty-2 reduced c-met expression and thus confirmed our findings in colorectal cancer (PNAS, 110: 8573-78, 2013). We further extended our studies to demonstrate that this pathway modulates gastrointestinal specific microRNAs (miRNAs) and regulates various oncogenes and tumor suppressor genes in colon cancer cells. Methods: RNA from control and shRNA sprouty-2 transfected cells were labeled with Hy5 and Hy3 respectively and hybridized to miRCURY LNA arrays. Unsupervised miRNA clustering was carried out and a heat map prepared with Java TreeView. MicroRNA targets were identified by Real-time PCR, western blotting and 3′UTR luciferase assays. Migratory phenotype of colon cancer cells was confirmed by cell migration and invasion assays in trans-well chambers. Cancer cells were transfected by miRNA mimics to assess the expression levels of target genes. Human colon cancer tissue microarrays were utilized to assess the expression of miRNA target genes. Human tumor sections were evaluated by immunofluorescence and immunohistochemical staining. Results: Sprouty-2 shRNA transfected stable cell lines demonstrated upregulation of tumor suppressive miRNAs and down-regulation of oncogenic miRNAs. Overexpression of gastrointestinal specific miRNA mimics inhibits colon cancer cells proliferation and metastasis. On the contrary, overexpression of miRNA inhibitor in colon cancer cells promotes proliferation and colonization. Studies further indicated that miRNA down-regulates expression of CDK7, RB1, AKT, FASL, IGF1R, EGFR and N-cadherin and up-regulates expression of P21 and E-cadherin. MiRNA regulated genes were responsible for cell cycle arrest, enhanced apoptosis and decreased metastasis. AKT was upregulated whereas E-cadherin was downregulated at the invasive fronts in human colon tumors. Conclusion: Sprouty-2/miRNA expression levels could be used to risk-stratify patients for CRC recurrence and sprouty-2 axis regulation may lead to the development of therapeutics in colon and lung cancer. Citation Format: Qiong Zhang, Vivek Vaish, Sharad Khare. Regulation of colon cancer metastasis by sprouty-2. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1466. doi:10.1158/1538-7445.AM2014-1466