Abstract 3690: Asiatic acid is an effective alternative agent targeting growth, angiogenesis and invasiveness of malignant gliomas

Abstract

Abstract Malignant gliomas are one of the most devastating and incurable tumors with approximately 77% of patients dying within first year of diagnosis. This poor prognosis is due to characteristics of glioma cells to proliferate uncontrollably, sustain excessive angiogenesis and invade aggressively. There has been no improvement in survival of glioma patients in past few decades and existing therapies, with tremendous side-effects, have largely failed. This suggests that immediate additional and alternative strategies are warranted to control this deadly malignancy. In this regard, preventing or inhibiting growth and progression of gliomas through non-toxic natural agents is one such strategy. An agent suited ideally against advance glioma is Asiatic Acid (AsA), the active constituent in Centella asiatica; both Centella asiatica extract and pure AsA are extensively used in traditional medicine to treat neurological disorders. Here we analyzed the anti-cancer efficacy of AsA against glioma cells both in vitro and in vivo. AsA treatment (10-100 microM, 6-24 hrs) significantly decreased cell viability in U87, LN18 and U118 glioma cells, together with strong apoptotic cell death. AsA treatment (6 hrs) in glioma cells caused PARP, Bid and caspases (3, 9 and 8) cleavage, activated JNK1/2, and decreased phosphorylated-Akt and survivin. Use of pan-caspase inhibitor (z-VAD.fmk) confirmed that AsA-induced apoptosis is caspase-dependent. Next, we studied whether AsA could target the pro-angiogenic effects of glioma cells. We observed that AsA treatment at non-cytotoxic doses significantly impairs potency of glioma cells (U87 and LN18) to promote capillary formation by HUVEC (human umbilical vein endothelial cells) and HBMEC (human brain microvascular endothelial cells) on matrigel. Further, AsA (5-20 microM) significantly inhibited VEGF-induced growth of HUVEC and HMBEC. We also observed remarkable anti-migratory effects of AsA treatment (5-20 microM) in wound healing assay and anti-invasive potential in Boyden chambers against glioma cells. In a novel assay developed by us, we further established the inhibitory effects of AsA on fibronectin-induced motility in glioma cells. Additional mechanistic studies revealed that AsA strongly increases intracellular Ca++ levels; and antiproliferative and antimigratory effects of AsA were largely compromised in the presence of Ca++ chelating agent BAPTA. We also established for the first time in vivo anti-cancer efficacy of AsA using xenograft model. AsA feeding (30 mg/kg body weight dose in saline) for 5 weeks significantly decreased U87 xenografts volume by 54% (p value less than 0.05) and strongly inhibited tumor vasculature without causing any adverse effects to animals. Together, these results suggest that AsA could be an effective alternative agent against malignant glioma and recommend its clinical use. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3690. doi:10.1158/1538-7445.AM2011-3690