Withaferin A causes FOXO3a- and Bim-dependent apoptosis and inhibits growth of human breast cancer cells in vivo.

Department of Pharmacology and Chemical Biology, and University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Cancer Research (Impact Factor: 9.28). 10/2008; 68(18):7661-9. DOI: 10.1158/0008-5472.CAN-08-1510
Source: PubMed

ABSTRACT Withaferin A (WA) is derived from the medicinal plant Withania somnifera, which has been safely used for centuries in Indian Ayurvedic medicine for treatment of different ailments. We now show, for the first time, that WA exhibits significant activity against human breast cancer cells in culture and in vivo. The WA treatment decreased viability of MCF-7 (estrogen-responsive) and MDA-MB-231 (estrogen-independent) human breast cancer cells in a concentration-dependent manner. The WA-mediated suppression of breast cancer cell viability correlated with apoptosis induction characterized by DNA condensation, cytoplasmic histone-associated DNA fragmentation, and cleavage of poly-(ADP-ribose)-polymerase. On the other hand, a spontaneously immortalized normal mammary epithelial cell line (MCF-10A) was relatively more resistant to WA-induced apoptosis compared with breast cancer cells. The WA-mediated apoptosis was accompanied by induction of Bim-s and Bim-L in MCF-7 cells and induction of Bim-s and Bim-EL isoforms in MDA-MB-231 cells. The cytoplasmic histone-associated DNA fragmentation resulting from WA exposure was significantly attenuated by knockdown of protein levels of Bim and its transcriptional regulator FOXO3a in both cell lines. Moreover, FOXO3a knockdown conferred marked protection against WA-mediated induction of Bim-s expression. The growth of MDA-MB-231 cells implanted in female nude mice was significantly retarded by 5 weekly i.p. injections of 4 mg WA/kg body weight. The tumors from WA-treated mice exhibited reduced cell proliferation and increased apoptosis compared with tumors from control mice. These results point toward an important role of FOXO3a and Bim in regulation of WA-mediated apoptosis in human breast cancer cells.

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    ABSTRACT: BackgroundTumour cells show greater dependency on glycolysis so providing a sufficient and rapid energy supply for fast growth. In many breast cancers, estrogen, progesterone and epidermal growth factor receptor-positive cells proliferate in response to growth factors and growth factor antagonists are a mainstay of treatment. However, triple negative breast cancer (TNBC) cells lack receptor expression, are frequently more aggressive and are resistant to growth factor inhibition. Downstream of growth factor receptors, signal transduction proceeds via phosphatidylinositol 3-kinase (PI3k), Akt and FOXO3a inhibition, the latter being partly responsible for coordinated increases in glycolysis and apoptosis resistance. FOXO3a may be an attractive therapeutic node to target for TNBC. Therefore we have undertaken a systematic review of FOXO3a as a target for breast cancer therapeutics.MethodsArticles from NCBI were retrieved systematically when reporting primary data about FOXO3a expression in breast cancer cells after cytotoxic drug treatment.ResultsIncreased FOXO3a expression is common following cytotoxic drug treatment and is associated with apoptosis and cell cycle arrest. There is some evidence that metabolic enzyme expression is also altered and that this effect is also elicited in TNBC cells. FOXO3a expression serves as a positive prognostic marker, especially in estrogen (ER) receptor positive cells.DiscussionFOXO3a is upregulated by a number of receptor-dependent and -independent anti-cancer drugs and associates with apoptosis. The identification of microRNA that regulate FOXO3a directly suggest that it offers a tangible therapeutic target that merits wider evaluation.
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    ABSTRACT: Transformation of Withania somnifera was carried out by using three Agrobacterium rhizogenes strains (ATCC 15834, R1000 and K599) for hairy root induction. Induction of hairy root was carried out in leaf, petiole and internodal explants. Hairy root induction was successful only in ATCC 15834 and R1000. The highest frequency of hairy root was obtained in petiole explants (64%) infected with R1000 and it resulted in five distinct morpho-types (callus (fragile), callus (hard), callus + hairy roots, hairy roots and callusing roots). The frequency of R1000 transformation was increased up to 93.2% by the addition of acetosyringone during various steps of infection. Molecular identification through PCR analysis of rolC confirmed the presence of Ri T-DNA. The half strength Murashige and Skoog (MS) liquid medium was found to be the best medium that supports the high root biomass accumulation than the other tested medium types (MS full strength, Gamborg B5 medium (B5) full strength and B5 half strength). High performance liquid chromatography (HPLC) analysis of hairy roots revealed the accumulation of withaferin-A (72.3 mg/g dw). This study reports the influence of Agrobacterium strains, explant types and acetosyringone in the hairy root induction of W. somnifera.
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