Global transcriptome analysis reveals partial estrogen-like effects of karanjin in MCF-7 breast cancer cells

Abstract

Karanjin, an abundantly occurring furanoflavonoid in edible and non-edible legumes, exerts diverse biological effects in vivo, and in vitro. Its potential as an anticancer agent is also gaining traction following recent demonstrations of its anti-proliferative, cell cycle inhibitory, and pro-apoptotic effects. However, the universality of its anticancer potential is yet to be scrutinized, particularly so because flavonoids can act as selective estrogen receptor modulators (SERMs). Even the genomic correlates of its biological activities are yet to be examined in hormone responsive cells. This paper presents the early and direct transcriptomic footprint of 10 M karanjin in MCF-7 breast cancer cells, using next generation sequencing technology (RNA-seq). We show that karanjin-modulated gene-expression repertoire is enriched in several hallmark gene sets, which include early estrogen-response, and G2/M checkpoint genes. Genes modulated by karanjin overlapped with those modulated by 1 nM 17{beta}-estradiol (E2), or 1 M tamoxifen. Karanjin altered the expression of selected estrogen-regulated genes in a cell-type, and concentration dependent manner. It downmodulated the expression of ER protein in MCF-7 cells. Furthermore, ER knockdown negatively impacted karanjins ability to modulate the expression of selected E2 target genes. Our data suggest that karanjin exerts its effects on ER-positive breast cancer cells, at least in part, via ER. The apparent SERM-like effects of karanjin pose a caveat to the anticancer potential of karanjin. In-depth studies on cell-type and concentration-dependent effects of karanjin may bring out its true potential in endocrine therapies.