Mahanine mediated therapeutic inhibition of estrogen receptor-α and CDK4/6 expression, decipher the chemoprevention-signaling cascade in preclinical model of breast cancer

Mahanine (MH), a naturally occurring carbazole alkaloid, isolated from Ayurvedic medicinal plant Murraya koenigii (L.) Spreng, has been shown to have various pharmacological properties, including its inhibitory activity against different breast cancers (BC) subtypes.While MH triggers apoptosis in BC cells regardless of subtype, the specific mechanism of MH action is not fully understood. In this study, we show the effect of MH in preventing BC progression by inducing apoptosis in relation to estrogen receptor-α (ERα) and cell cycle regulatory proteins.To assess the pharmacological activity in various in vitro and in vivo tests, isolated and pure MH was used. To conclude the study, cutting edged molecular biology techniques including Western blot analysis, enzyme-linked immunosorbent assay (ELISA), molecular simulation study, and other related software analysis were employed.MH demonstrated dose dependent cell viability against drug sensitive (MCF-7 and MDA-MB-231) and paclitaxel resistant (MCF-7TR and MDA-MB-231TR) BC cells. MH also exhibited synergistic activity with tamoxifen (TAM) against estrogen receptor positive (ER+) BC cells by inhibiting ERα expression in MCF-7 cells and N-Methyl-N-nitrosourea (MNU)-induced mammary tumor in a dose-dependent manner while having no effect on vinculin expression. In addition, MH inhibited cell cycle regulatory genes namely CDK1/CDK4/CDK6/CDC25A and neo-angiogenesis through downregulation of CD31/PECAMs in MCF-7, MDA-MB-231 cells and mammary tumors from MNU-induced rats. MH therapy has been shown to be significantly able to lower the serum leptin level and to be beneficial against the initiation of tumor development in SD rats for up to 12 weeks. Molecular modeling study revealed that MH has antagonized the effectiveness of several types of estrogen those bind to the ERα and has comparable binding efficacy to TAM.Overall, the current investigation showed the ability of MH to modify cell cycle genes especially CDK4 and CDK6 might be responsible for its anticancer activity against different breast cancer subtypes. Additionally, this study will aid in advancing MH translational research to the clinical trial stage.