Orientin, a Bio-Flavonoid from Trigonella hamosa L., Regulates COX-2/PGE-2 in A549 Cell Lines via miR-26b and miR-146a

Abstract

Cancer is a severe health condition and considered one of the major healthcare issues and is in need of innovative strategy for a cure. The current study aimed to investigate the chemical profile of Trigonella hamosa L. and a potential molecular approach to explain its regulation in cancer progression through an inflammatory mediator (COX-2) in A549 non-small lung cancer cell lines via in silico, mechanistic and molecular aspects. T. hamosa was extracted and then subjected to a CCK-8 cell viability assay in different cancer cell lines including MDA-MB-231, A549 and HCT-116. Total extract was subjected to several chromatographic techniques to yield orientin (OT); the structure was elucidated by inspection of NMR spectroscopic data. To achieve anticancer effects of OT, a cell viability assay using a CCK-8 kit, immunoprecipitation by Western blot, cell migration using a wound healing assay, cell invasion using a Matrigel-Transwell assay, apoptosis by AO/EB dual staining, flow cytometric analysis and DAPI staining, a silenced COX-2 model to determine PGE-2 production and real-time PCR and Western blot of BCL-2, CYP-1A1, iNOS and COX-2 markers were carried out. The results demonstrated that OT decreased the cell proliferation and controlled cell migration and invasive properties. OT destabilized the COX-2 mRNA and downregulated its expression in A549 cell lines. Virtual binding showed interaction (binding energy −10.43) between OT and COX-2 protein compared to the selective COX-2 inhibitor celecoxib (CLX) (binding energy −9.4). The OT-CLX combination showed a superior anticancer effect. The synergistic effect of OT-CLX combination was noticed in controlling the migration and invasion of A549 cell lines. OT-CLX downregulated the expression of BCL-2, iNOS and COX-2 and activated the proapoptotic gene CYP-1A1. OT mitigated the COX-2 expression via upregulation of miR-26b and miR-146a. Interestingly, COX-2-silenced transfected A549 cells exhibited reduced expression of miR-26b and miR-146a. The findings confirmed the direct interaction of OT with COX-2 protein. PGE-2 expression was quantified in both naïve and COX-2-silenced A549 cells. OT downregulated the release of PGE-2 in both tested conditions. These results confirmed the regulatory effect of OT on A549 cell growth in a COX-2-dependent manner. OT activated apoptosis via activation of CYP-1A1 expression in an independent manner. These results revealed that the OT-CLX combination could serve as a potential synergistic treatment for effective inflammatory-mediated anticancer strategies.