title: Palmatine hydrochloride mediated photodynamic inactivation of breast cancer MCF-7 cells: Effectiveness and mechanism of action.
abstract: Breast cancer is one of the commonest malignant tumors threatening to women. The present study aims to investigate the effect of photodynamic action of palmatine hydrochloride (PaH), a naturally occurring photosensitizer isolated from traditional Chinese medicine (TCM), on apoptosis of breast cancer cells. Firstly, cellular uptake of PaH in MCF-7 cells was measured and the cytotoxicity of PaH itself on breast cancer MCF-7 cells was estimated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Subcellular localization of PaH in MCF-7 cells was observed using confocal laser scanning microscopy (CLSM). For photodynamic treatment, MCF-7 cells were incubated with PaH and then irradiated by visible light (470nm) from a LED light source. Photocytotoxicity was investigated 24h after photodynamic treatment using MTT assay. Cell apoptosis was analyzed 18h after photodynamic treatment using flow cytometry with Annexin V/PI staining. Nuclear was stained using Hoechst 33342 and observed under a fluorescence microscope. Intracellular production of reactive oxygen species (ROS) was studied by measuring the fluorescence of 2, 7-dichlorofluorescein (DCF) using a flow cytometry. Results showed that PaH treatment alone had no or minimum cytotoxicity to MCF-7 cells after incubation for 24h in the dark. After incubation for 40min, the cellular uptake of PaH reached to the maximum, and PaH mainly located in mitochondria and endoplasmic reticulum of MCF-7 cells. Photodynamic treatment of PaH demonstrated a significant photocytotoxicity on MCF-7 cells, induced remarkable cell apoptosis and significantly increased intracellular ROS level. Our findings demonstrated that PaH as a naturally occurring photosensitizer induced cell apoptosis and significantly killed MCF-7 cells.
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Qicai
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China.
authors.forename: Changhu
authors.initials: C
authors.lastname: Xue
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Albert Wingnang
authors.initials: AW
authors.lastname: Leung
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Laboratory of Food Science and Human Health, College of Food Science and Engineering, Ocean University of China, Qingdao, China. Electronic address: tangqingjuan@ouc.edu.cn.
authors.forename: Qing-Juan
authors.initials: QJ
authors.lastname: Tang
authors.affiliation: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China. Electronic address: xcshan@163.com.
authors.forename: Chuanshan
authors.initials: C
authors.lastname: Xu
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D001600:Berberine Alkaloids / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008027:Light; D061986:MCF-7 Cells; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D001600:Berberine Alkaloids; D017319:Photosensitizing Agents; C005413:palmatine
keywords: Breast cancer; Cell apoptosis; Palmatine hydrochloride; Photodynamic therapy; Reactive oxygen species; Subcellular localization