Cancer: Colon, breast, acute myeloid leukemia
Action: MDR, aromatase inhibition, induces apoptosis
Induces Apoptosis, Colorectal Cancer
Puerarin is isolated from Pueraria radix (Pueraria lobata [(Willd.) Ohwi]) and has beneficial effects on cardiovascular, neurological, and hyperglycemic disorders, as well as anti-cancer properties. Puerariae radix (PR) is a popular natural herb and a traditional food in Asia, which has anti-thrombotic and anti-allergic properties and stimulates estrogenic activity.
Methyl thiazolyl tetrazolium assay (MTT) assay revealed a dose-dependent reduction of HT-29 cellular growth in response to puerarin treatment. Apoptosis was observed following treatments with ³ 25µM puerarin, as reflected by the appearance of the subdiploid fraction and NDA fragmentations. Puerarin also affects the expression of apoptosis-associated genes, revealing an increase of bax and decreases of c-myc and bcl-2.
Finally, puerarin treatment significantly increased the activation of caspase-3, a key executioner of apoptosis. These findings indicate that puerarin may act as a chemo-preventive and/or chemotherapeutic agent in colon cancer cells by reducing cell viability and inducing apoptosis (Li, et al., 2006).
Induces Apoptosis, Breast Cancer
Puerarin exhibits a dose-dependent inhibition of cell growth in HS578T, MDA-MB-231, and MCF-7 cell lines. Results from cell-cycle distribution and apoptosis assays revealed that puerarin induced cell apoptosis through a caspase-3-dependent pathway and mediated cell-cycle arrest in the G2/M phase. It is therefore suggested that puerarin may act as a chemo-preventive and/or chemotherapeutic agent against breast cancer by reducing cell viability and inducing apoptosis (Lin et al., 2009).
Breast Cancer, MDR
Purearin down-regulates MDR1 expression in MCF-7/adriamycin (MCF-7/adr), a human breast MDR cancer cell line. Multi-drug resistance (MDR) is a major obstacle in cancer chemotherapy and its inhibition is an effective way to reverse cancer drug resistance. Puerarin treatment significantly inhibited MDR1 expression, MDR1 mRNA and MDR1 promoter activity in MCF-7/adr cells. The suppression of MDR1 was accompanied by partial recovery of intracellular drug accumulation, leading to increased toxicity of adriamycin and fluorescence of rhodamine 123, indicating that puerarin reversed the MDR phenotype by inhibiting the drug efflux function of MDR1. Puerarin stimulated AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase and glycogen synthase kinase-3beta phosphorylation, but puerarin decreased cAMP-responsive element-binding protein phosphorylation.
The puerarin-induced suppression of MDR1 expression was reduced by AMPK inhibitor (compound C). Furthermore, both MDR1 protein expression and the transcriptional activity of cAMP-responsive element (CRE) were inhibited by puerarin and protein kinase A/CRE inhibitor (H89). Taken together, these results suggested that puerarin down-regulated MDR1 expression via nuclear factor kappa-B and CRE transcriptional activity-dependent up-regulation of AMPK in MCF-7/adr cells (Hien et al., 2010).
Acute Myeloid Leukemia (AML)
The results showed that a certain concentration of puerarin (PR) could inhibit the proliferation of these four cell lines effectively in time-and dose-dependent manners, and the intensity of inhibition on four kinds of acute myeloid leukemia (AML) cell lines was from high to low as follows: NB4>Kasumi-1>U937>HL-60. Meanwhile, PR could also change cycle process, cell proportion in G1/G0 phase decreased, cells in S phase increased and Sub-diploid peak also appeared. It is concluded that PR can selectively inhibit the proliferation of four AML cell lines and block cell-cycle process, especially for NB4 cells (Shao et al., 2010).
Aromatase Inhibition
Aromatase P450 (P450 (arom)) is overexpressed in endometriosis, endometrial cancers and uterine fibroids. With weak estrogen agonists/antagonists and some other enzymatic activities, isoflavones are increasingly advocated as a natural alternative to estrogen replacement therapy (ERT) and are available as dietary supplements. Puerarin is a major isoflavonoid compound isolated from Pueraria lobata (ge gen).
Yu et al. (2008) found that puerarin exerted a time-course effect on the inhibition of c-jun mRNA, which parallelled that of P450(arom). The suppression of P450(arom) expression and activity by puerarin treatment may associate with the down-regulation of transcription factor AP-1 or c-jun.
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