Patrinia scabiosaefolia inhibits the proliferation of colorectal cancer in vitro and in vivo via G1/S cell cycle arrest.

Patrinia scabiosaefolia (PS) has long been used as an important component in traditional Chinese medicine formulas to treat gastrointestinal malignancies including colorectal cancer (CRC). We recently reported that PS can inhibit CRC growth through induction of apoptosis and inhibition of tumor angiogenesis. To further elucidate the mode of action of PS, in the present study, we used a CRC mouse xenograft model and a human CRC cell line HT-29 to evaluate the effect of the ethanol extract of PS (EEPS) on cancer cell proliferation and investigated the underlying molecular mechanisms. We found that EEPS inhibited CRC growth both in vivo and in vitro, which was associated with the inhibitory effects of EEPS on cancer cell proliferation. In addition, EEPS treatment significantly blocked G, to S phase cell cycle progression in HT-29 cells. Moreover, EEPS treatment decreased the expression of pro-proliferative CyclinD1 and CDK4, at both the mRNA and protein levels. Thus, inhibition of cell proliferation via G(1)/S cell cycle arrest might be a potential mechanism whereby PS effectively treats cancers.