Natural plant extracts mediated expression regulation of TGF-β receptors and SMAD genes in human cancer cell lines.

Abstract

Transforming growth factor beta (TGF-β) superfamily has key role in cell proliferation which leads to tumor promoting activities at metastatic stage of cancer. Inhibition of transforming growth factor beta receptor (TGFβR) signaling pathway can provide better therapeutic strategy to control cancer. Natural products are best known for their safety, less toxic nature, antioxidant characteristics making them a promising candidate to inhibit TGFβR signaling pathway. Crude methanolic extracts (CMEs) of 16 selected plants were prepared by using maceration method and subjected to phytochemical assays for identification of major phytometabolites particularly cancer chemopreventive antioxidant constituents. Total flavonoid content of all plants CME was > 0.6mg/ml exhibiting the Cichorium intybus contains comparatively highest amount of total flavonoid content (0.53mg/ml). Scanvenging activity of all plants was determined having IC50 ranges between 2 and 88 (µg/ml) while Moringa oleifera revealed the maximum scavenging activity (IC50 2.03µg/ml). Comparative cytotoxicity of plant extracts was evaluated in HUH and MCF-7 cell lines using 3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) colorimetric assay. The nine active plant extracts i.e. Fagonia cretica, Argemone Mexicana, Rubus fruticosus, M. oleifera, Punica granatum, Cichorium intybus, Xanthium strumarium, Carissa opaca, Cyperus rotundus were identified based on their high antiproliferative activity > 50% against cancer cell lines and subjected to relative expression studies. Modulation of TGFβ signaling molecules (i.e.TGFβR1, 2 & 3, SMAD3, SMAD5) and ubiquitous proteins i.e. SMURF1 and SMURF2 genetic expression by potent extracts was determined by RT-PCR using GAPDH (housekeeping gene) as gene of reference. This present study revealed that CME of Fagonia cretica and Argemone mexicana significantly inhibit TGF beta mediated signaling cascade by downregulating the gene expression fold change > 1 of TGFβR 1, 2 & 3 and receptor associated complex protein SMAD3 as compared to control.