Abstract

Background: Cucurbitacin-induced apoptosis and inhibition of cell growth can render several cancers ineffective. The microbial transformation of cucurbitacin-E-glucoside to cucurbitacin- E was carried out by Curvularia lunata (NRRL 2178). Moreover, in vitro anticancer activity against the MCF-7 cell line as well as in vivo anticancer activity against dimethylbenz (a) anthracene (DMBA)-induced breast cancer in mice using cucurbitacin-E was evaluated.

Methods: The cucurbitacin-E-glucoside was biotransformed by Curvularia lunata to cucurbitacin- E, and the isolated compound was tested in vitro against the MCF-7 cell line, and its IC50 was calculated. LD50 of cucurbitacin-E was estimated in mice, and its protective activity against DMBA-induced cancer in mice was studied. Breast cancer induction was done by a single-dose subcutaneous administration of DMBA (50 mg). Plasma ALT, AST, ALP, and LDH, as well as GSH, SOD, GPx, MDA, TNF-α, IL-6, and tumor suppressor P53 assays, were used to assess cucurbitacin- E's capacity to protect the liver and breast against DMBA-induced toxicity. Moreover, by assessing the gene expression of tumor suppressor genes (BRCA 1 and 2) and conducting histopathological analysis, the suppressive effect of cucurbitacin-E was examined.

Results: The IC50 value of cucurbitacin-E against MCF-7 cell lines equals 72.15 ± 0.64 μg/ml. LD50 of cucurbitacin-E given orally in adult mice is equal to 1200 mg/kg b.w. The levels of plasma ALT, AST, ALP, and LDH were decreased significantly in DMBA-treated mice when administered with cucurbitacin-E at 1/50 LD50 (24 mg/kg/b.w.) and 1/20 LD50 (60 mg/kg/b.w.). In breast tissue, the levels of GSH, SOD, GPx, and P53 were significantly increased, as were decreased levels of TNF-α, IL-6, P53, and MDA. Conversely, there was a downregulation in the mRNA expression levels of BRCA1 and BRCA2. The histopathological analysis revealed that cucurbitacin-E management improved the tissue architecture of breast tumors.

Conclusions: These findings demonstrate the ability of cucurbitacin-E to inhibit cancer cells in the rat breast by controlling oxidative stress and inflammatory biomarkers, as well as downregulating the mRNA expression levels of BRCA1 and BRCA2.

Keywords: Cucurbitacin-E, MCF-7, Curvularia lunata, DMBA, P53, BRCA1 and BRCA2.