Licochalcone A induces autophagy through PI3K/Akt/mTOR inactivation and autophagy suppression enhances Licochalcone A-induced apoptosis of human cervical cancer cells.

// Jen-Pi Tsai 1, 2, * , Chien-Hsing Lee 3, 4, * , Tsung-Ho Ying 5 , Chu-Liang Lin 6 , Chia-Liang Lin 6 , Jung-Tsung Hsueh 6 , Yi-Hsien Hsieh 6, 7, 8 1 Department of Nephrology, Buddhist Dalin Tzu Chi General Hospital, Chiayi, Taiwan 2 School of Medicine, Tzu Chi University, Hualien, Taiwan 3 Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan, Taiwan 4 Division of Pediatric Surgery, Department of Surgery, Children's Hospital of China Medical University, Taichung, Taiwan 5 Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung, Taiwan 6 Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung, Taiwan 7 Department of Biochemistry, School of Medicine, Chung Shan Medical University, Taichung, Taiwan 8 Clinical laboratory, Chung Shan Medical University Hospital, Taichung, Taiwan * These authors contributed equally to this work Correspondence to: Yi-Hsien Hsieh, e-mail: hyhsien@csmu.edu.tw Keywords: Licochalcone A, apoptosis, autophagy, cervical cancer Received: May 04, 2015      Accepted: July 20, 2015      Published: July 31, 2015 ABSTRACT The use of dietary bioactive compounds in chemoprevention can potentially reverse, suppress, or even prevent cancer progression. However, the effects of licochalcone A (LicA) on apoptosis and autophagy in cervical cancer cells have not yet been clearly elucidated. In this study, LicA treatment was found to significantly induce the apoptotic and autophagic capacities of cervical cancer cells in vitro and in vivo . MTT assay results showed dose- and time-dependent cytotoxicity in four cervical cancer cell lines treated with LicA. We found that LicA induced mitochondria-dependent apoptosis in SiHa cells, with decreasing Bcl-2 expression. LicA also induced autophagy effects were examined by identifying accumulation of Atg5, Atg7, Atg12 and microtubule-associated protein 1 light chain 3 (LC3)-II. Treatment with autophagy-specific inhibitors (3-methyladenine and bafilomycin A1) enhanced LicA-induced apoptosis. In addition, we suggested the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of mTOR pathway by LicA. Furthermore, the inhibition of PI3K/Akt by LY294002/si-Akt or of mTOR by rapamycin augmented LicA-induced apoptosis and autophagy. Finally, the in vivo mice bearing a SiHa xenograft, LicA dosed at 10 or 20 mg/kg significantly inhibited tumor growth. Our findings demonstrate the chemotherapeutic potential of LicA for treatment of human cervical cancer.