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350

CHM-1, a novel synthetic quinolone with potent and selective antimitotic antitumor activity against human hepatocellular carcinoma in vitro and in vivo
Shih-Wei Wang,1 Shiow-Lin Pan,1 Yu-Chun Huang,1 Jih-Hwa Guh,2 Po-Cheng Chiang,2 Der-Yi Huang,1 Sheng-Chu Kuo,3 Kuo-Hsiung Lee,4 and Che-Ming Teng1
Pharmacological Institute and 2School of Pharmacy, College of Medicine, National TaiwanUniversity, Taipei, Taiwan; 3 Graduate Institute of Pharmaceutical Chemistry, China Medical University, Taichung, Taiwan; and 4Natural Products Laboratory, School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
1

nucleus. Small interfering RNA targeting of AIF substantially attenuated CHM-1-induced AIF translocation. Importantly, CHM-1 inhibited tumor growth and prolongedthe lifespan in mice inoculated with HA22T cells. In conclusion, we show that CHM-1 exhibits a novel antimitotic antitumor activity against human hepatocellular carcinoma both in vitro and in vivo via a caspase-independent pathway. CHM-1 is a promising chemotherapeutic agent worthy of further development into a clinical trial candidate for treating cancer, especially hepatocellular carcinoma. [MolCancer Ther 2008;7(2):350 – 60]

Abstract
Hepatocellular carcinoma is highly chemoresistant to currently available chemotherapeutic agents. In this study, 2¶-fluoro-6,7-methylenedioxy-2-phenyl-4-quinolone (CHM-1), a synthetic 6,7-substituted 2-phenyl-4-quinolone, was identified as a potent and selective antitumor agent in human hepatocellular carcinoma. CHM-1 induced growth inhibition of HA22T,Hep3B, and HepG2 cells in a concentration-dependent manner but did not obviously impair the viability of normal cells at the IC50 for liver cancer cells. CHM-1-induced apoptosis was also characterized by immunofluorescence microscopy. CHM-1 interacted with tubulin at the colchicine-binding site, markedly inhibited tubulin polymerization both in vitro and in vivo, and disrupted microtubuleorganization. CHM-1 caused cell cycle arrest at G2-M phase by activating Cdc2/cyclin B1 complex activity. CHM-1-induced cell death, activation of Cdc2 kinase activity, and elevation of MPM2 phosphoepitopes were profoundly attenuated by roscovitine, a specific cyclin-dependent kinase inhibitor. CHM-1 did not modulate the caspase cascade, and the pan-caspaseinhibitor z-VAD-fmk did not abolish CHM-1-inducedcell death. However, CHM-1 induced the translocation of apoptosis-inducing factor (AIF) from mitochondria to the

Introduction
Hepatocellular carcinoma ranks as one of the most common cancers in the world (1). In Taiwan, where the incidence of hepatocellular carcinoma is among the highest in the world, chronic infection with hepatitis B virus appears to account for at least 70% ofhepatocellular carcinoma (2). The incidence of hepatocellular carcinoma is dramatically increasing in the United States and other developed countries most likely due to the increasing prevalence of hepatitis C (3). Unfortunately, most patients with hepatocellular carcinomas are not curable because extensive resection is not possible, there is massive liver dysfunction caused by cirrhosis, or the disease isnot identified at an early stage. Systemic chemotherapy and chemoembolization are the remaining treatment options in advanced hepatocellular carcinoma (4). However, hepatocellular carcinoma is well known for its expression of the multidrug resistance gene and its poor response to currently available chemotherapeutic agents (5, 6). Therefore, innovations to explore effective chemotherapeutic agentsfor hepatocellular carcinoma are urgently needed. Antimitotic agents interact in the tubulin/microtubule system and constitute a major class of anticancer drugs (7). Because microtubules play crucial roles in the regulation of the mitotic apparatus, disrupting microtubules can induce cell cycle arrest in M phase, consequentially triggering of signals for apoptosis. Known antimitotic agents...