Abstract 3198: Extract from Scutellaria baicalensis Georgi inhibits prostate cancer growth in bone

Abstract

Abstract Prostate cancer (PCa) frequently metastasizes to bone forming predominantly osteoblastic lesions with underlined osteolytic components. Because current therapies are generally ineffective in PCa skeletal metastases, patients seek alternative medicines such as herbal medicines, which have been used for many centuries in Asian countries. The purpose of this study was to identify Chinese herbal medicines that may be effective in PCa skeletal metastasis. We first screened 130 Chinese herbs (ethanol extracts) for anti-proliferation effects by non-radioactive cell proliferation assay in LNCaP and C4-2B PCa cells. We found five extracts with anti-proliferation activity including extract from Scutellaria baicalensis Georgi (Huang Qin, HQ), which had the strongest effect. We next evaluated HQ's ability to induce apoptosis of LNCaP and C4-2B cells. HQ, in a dose-dependent manner, induced apoptosis of both cell lines based on TUNEL assay. In addition, HQ induced apotosis-related gene caspase-3 and suppressed bcl-2 expressions in both cell lines. Therefore, we tested if HQ (1mg per mouse three times a week for 8 weeks intraperitoneally) could diminish establishment of skeletal metastases in mice. We injected C4-2B cells into tibia of SCID mice. The animals were randomized into two groups to receive either HQ or vehicle only (n=8/group). At 8 weeks post-tumor injection, mice were sacrificed and tumor establishment in the skeleton was determined using radiography, dual energy x-ray absorptiometry and histology. Radiographic and histological lesions were present in 7/8 vehicle-treated mice and in 6/8 HQ-treated mice. However, the radiographically- and histologically-determined areas of the tumors in the HQ-treated mice were approximately 47% that of the vehicle-treated animals. We conclude that HQ has efficacy for inducing PCa cells apoptosis in vitro and has the ability to diminish growth of PCa in murine bone. Supported by NSF key project 81130046, NSF projects 81171993 and 81272415. Citation Format: Chaoqian Li, Hongwei Guo, Yi Lu, Jinlu Dai, Evan Keller, Jian Zhang. Extract from Scutellaria baicalensis Georgi inhibits prostate cancer growth in bone. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3198. doi:10.1158/1538-7445.AM2014-3198