Effects of Zeng Sheng Ping/ACAPHA on malignant brain tumor growth and Notch signaling.

Background/Aim: Zeng Sheng Ping (ZSP) is a traditional herbal remedy used to prevent progression and growth of neoplastic lesions. It has been shown to inhibit Notch2 expression in a murine lung cancer model, leading us to investigate its therapeutic potential in Notch-dependent brain tumors. Materials and Methods: 3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium (MTS), apoptosis, and quantitative real-time polymerase chain reaction (RT-PCR) analyses were performed in glioma and medulloblastoma cell lines, and morphological analyses in DAOY flank xenografts. Results: ZSP inhibited brain tumor growth in vitro, in part, by apoptotic induction. Down-regulation of the Notch2 receptor, the pathway target Hairy/Enhancer of Split homolog 1 (Hes1), and of the stem cell markers Nestin and CD133 was also observed. Reductions in tumor mass and increases in the necrotic fraction of DAOY xenografts, in mice treated with oral ZSP were also observed, but these were not significant. Conclusion: ZSP can block brain tumor growth and the expression of Notch pathway members and stem cell markers in vitro. Medulloblastoma and glioblastoma are the most common types of malignant cancer arising in the central nervous systems (CNS) of children and adults, respectively (1). Mortality is high, and more effective therapeutic agents are urgently needed. Complementary and alternative treatments are increasingly being used by oncology patients, but the mechanisms of action and efficacy of such therapies are often poorly understood. In this study, we focused on the traditional herbal remedy Zeng Sheng Ping (ZSP, also known as ACAPHA and antitumor B), for which preliminary preclinical (2, 3) and clinical (4) data have been published for solid tumors arising outside the CNS. ZSP is composed of six herbs (Sophora tonkinensis, Polygonum bistorta, Prunella vulgaris, Sonchus brachyotus, Dictamnus dasycarpus and Dioscorea bulbifera), and has been shown in different Chinese clinical studies to reduce the progression of histopathologically confirmed pre-cancerous esophageal squamous dysplasia to carcinoma by 48-52% compared to placebo (5-7). In a phase III study involving 449 patients with esophageal epithelial hyperplasia, ZSP reduced the progression of the disease from 24.8% to 3.3% (4). ZSP has also been shown to reduce the incidence of bladder cancer in rat models by 91% over 13 months (2), and the incidence of oral squamous cell carcinoma in two animal models, as well as to reduce oral lesions in human patients with oral leukoplakia (3). Finally, a 2004 study performed in the United States found that ZSP blocked progression of lung tumors in a mouse model harboring a dominant-negative p53 mutation and/or loss of one p16 (Ink4a) allele (8). Oligonucleotide-array analysis of ZSP- treated and untreated lung lesions identified expression alterations in members of the Notch pathway, including down- regulation of the Notch2 receptor in treated carcinomas. Brain tumors have active Notch signaling, with important roles played by Notch2 and other pathway members in medulloblastoma and glioblastoma, and suppression of pathway activity inhibiting tumor proliferation and survival (9-15). Current therapeutic approaches targeting Notch have focused on inhibiting gamma-secretase activity, but these can be associated with significant toxicity in the gut and other organs (16). We therefore sought to determine if ZSP might inhibit the growth of malignant brain tumors.