Objective: Our aim is to examine the ability of cisplatin-induced SASP of oral fibroblasts to promote pro-tumourigenic stromal-epithelial interactions in oral cancer and identify changes in the microRNA expression profile associated with the development of the SASP.
Method: Oral fibroblasts (OF) were treated with cisplatin to induce premature senescence (PS) as determined by senescence associated β-galactosidase (SA-β-gal) staining, qRT-PCR, human cytokine antibody array and zymography. MicroRNA expression profiles were examined using tiling low-density arrays (TLDA). Over expression of candidate miRNAs was achieved by transfection of synthetic precursors. The paracrine effects of PS and transfected OF on oral cancer-derived cells were assessed using transwells and 3D organotypic models.
Result: PS OF stained positive for SA-β-gal. Expression of p21/cip1 and p16INK4a were significantly increased in PS OF along with secretion of MMP2, IL-6, MCP-1, IGFBP-2 and angiogenin. Alterations in the levels of a number of microRNA with known or predicted targets involved in the development of SASP were identified. Conditioned media derived from both PS and transfected OF stimulated migration of oral cancer cells in vitro. In presence of PS OF, an increase in invasion of oral cancer cell lines were observed in organotypic models.
Conclusion: In this study we characterised the SASP of oral fibroblasts and have identified associated changes in the miRNA expression profile. This will provide an insight into pathways which may be associated with tumour recurrences and therapeutic failure frequently observed in oral cancer.