title: Effect of methoxychlor on Ca²⁺ homeostasis and apoptosis in HA59T human hepatoma cells.
abstract: Methoxychlor, an organochlorine pesticide, is thought to be an endocrine disrupter that affects Ca²⁺ homeostasis and cell viability in different cell models. This study explored the action of methoxychlor on cytosolic free Ca²⁺ concentrations ([Ca²⁺]i) and apoptosis in HA59T human hepatoma cells. Fura-2, a Ca²⁺-sensitive fluorescent dye, was applied to measure [Ca²⁺]i. Methoxychlor at concentrations of 0.1-1 μM caused a [Ca²⁺]i rise in a concentration-dependent manner. Removal of external Ca²⁺ abolished methoxychlor's effect. Methoxychlor-induced Ca²⁺ influx was confirmed by Mn²⁺-induced quench of fura-2 fluorescence. Methoxychlor-induced Ca²⁺ entry was inhibited by nifedipine, econazole, SK&F96365, and protein kinase C modulators. Methoxychlor killed cells at concentrations of 10-130 μM in a concentration-dependent fashion. Chelation of cytosolic Ca²⁺ with 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not prevent methoxychlor's cytotoxicity. Methoxychlor (10 and 50 μM) induced apoptosis concentration-dependently as determined by using Annexin V/propidium iodide staining. Together, in HA59T cells, methoxychlor induced a [Ca²⁺]i rise by inducing Ca²⁺ entry via protein kinase C-sensitive Ca²⁺-permeable channels, without causing Ca²⁺ release from stores. Methoxychlor also induced apoptosis that was independent of [Ca²⁺]i rises.
authors: Department of Ophthalmology, Kaohsiung Armed Force General Hospital, Kaohsiung 80284, Taiwan, Republic of China.
authors: Chi-Ting
authors: CT
authors: Horng
authors: Department of Nursing, Division of Basic Medical Sciences, Chang Gung University of Science and Technology, Chia-Yi 61363, Taiwan, Republic of China.
authors: Chiang-Ting
authors: CT
authors: Chou
authors: Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Hui-Wen
authors: HW
authors: Tseng
authors: Department of Medicine, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Jin-Shiung
authors: JS
authors: Cheng
authors: Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Hong-Tai
authors: HT
authors: Chang
authors: Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Po-Min
authors: PM
authors: Chang
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: I-Li
authors: IL
authors: Chen
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: Ming-Chi
authors: MC
authors: Hung
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: Yi-Jen
authors: YJ
authors: Tsai
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: Peng-Chih
authors: PC
authors: Tsai
authors: Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Wei-Zhe
authors: WZ
authors: Liang
authors: Department of Nursing, Tzu Hui Institute of Technology, Pingtung 92641, Taiwan, Republic of China.
authors: Chun-Chi
authors: CC
authors: Kuo
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: Daih-Huang
authors: DH
authors: Kuo
authors: Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Chin-Man
authors: CM
authors: Ho
authors: Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Jia-Rong
authors: JR
authors: Lin
authors: Department of Pharmacy, Tajen University, Pingtung 90741, Taiwan, Republic of China.
authors: Pochuen
authors: P
authors: Shieh
authors: Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan, Republic of China.
authors: Chung-Ren
authors: CR
authors: Jan
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006706:Homeostasis / Q000187:drug effects*; D006801:Humans; D007306:Insecticides / Q000494:pharmacology*; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D008731:Methoxychlor / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D008731:Methoxychlor; D002118:Calcium