Downregulation of Tumor Promotor Genes in Oryza Sativa Linn.-Induced Antiproliferative Activity of Human Squamous Carcinoma Cells

Objectives: Oral cancer represents the third leading cause of death in Southeast Asia and targeted therapy could prevent or delay disease etymology. Oryza sativa Linn. (OS) extract has been implicated as an antitumor agent in many cancer types, however none has been investigated in human squamous carcinoma-2 (HSC-2) cells, thus we aim to investigate the effects of OS on HSC-2 cells. Methods: Our study investigated the growth inhibitory effects of an ethanolic extract of OS on HSC-2 cells by BrdU ELISA and MTT assays, as well as changes in tumor promoter genes using RT-qPCR and western blotting. Results: We found that OS was able to induce cell cytotoxicity and inhibit HSC-2 proliferation. OS also decreased the expression of genes involved in the TGF-β/Smads signaling pathway and genes involved in cell motility such as GPNMB, ITGB6, and E2F1 by RT-qPCR. Western blotting confirmed the downregulation of TGF-β1 by OS. Co-treatment of OS and 5-Flurouracil also reversed Snail and Slug overexpression caused by HSC-2 exposure to 5-Flurouracil. Conclusion: Together, these results indicate that OS can inhibit HSC-2 cell proliferation and this may involve TGF-β1 downregulation. Thus, this study shows OS could be useful for the treatment of patients with squamous carcinoma.