Helen Chan
Queen's University
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Featured researches published by Helen Chan.
Cancer Biology & Therapy | 2005
Cheong-Yip Ho; Chi-Fai Kim; K.N. Leung; Fung Kwok-Pui; Tak-Fu Tse; Helen Chan; Clara Bik-San Lau
Coriolus versicolor (CV), also called Yunzhi, has been demonstrated to exert anti-tumor effects on various types of cancer cells, but the underlying mechanism has not been fully elucidated. The present study aimed to evaluate the in vitro anti-tumor activity of a standardized aqueous ethanol extract prepared from CV on four breast cancer cell lines using MTT assay, and test whether the mechanism involves apoptosis induction and modulation of p53 and Bcl-2 protein expressions using cell death detection ELISA, p53 and Bcl-2 ELISAs respectively. Our results demonstrated that the CV extract dose-dependently suppressed the proliferation of three breast tumor cell lines, with ascending order of IC50 values: T-47D, MCF-7, MDA-MB-231, while BT-20 cells were not significantly affected. Tumoricidal activity of the CV extract was found to be comparable to a chemotherapeutic anti-cancer drug, mitomycin C. Nucleosome productions in apoptotic MDA-MB-231, MCF-7 and T-47D cells were significantly augmented in a time-dependent manner and paralleled the anti-proliferative activity of CV extract. Expression of p53 protein was significantly upregulated only in T-47D cells treated with the CV extract in a dose- and time-dependent fashion, but not in MCF-7 (except at 400 ?g/ml after 16 h) and MDA-MB-231 cells. The CV extract significantly induced a dose-dependent downregulation of Bcl-2 protein expression in MCF-7 and T-47D cells, but not in MDA-MB-231 cells. These results suggested that apoptosis induction, differentially dependent of p53 and Bcl-2 expressions, might be the possible mechanism of CV extract-mediated cytotoxicity in human breast cancer cells in vitro.
Current Medicinal Chemistry | 2017
Jack Ho Wong; Stephen Cho Wing Sze; Tzi Bun Ng; Randy Chi Fai Cheung; Chit Tam; Kalin Yanbo Zhang; Xiuli Dan; Yau Sang Chan; William Chi-shing Cho; Charlene Cheuk Wing Ng; Mary Miu Yee Waye; Wei-Cheng Liang; Jin-fang Zhang; Jie Yang; Xiuyun Ye; Juan Lin; Xiujuan Ye; Hexiang Wang; Fang Liu; David W. Chan; Hys Ngan; Ou Sha; Guohui Li; Ryan Tse; Tak Fu Tse; Helen Chan
The purpose of this account is to review the compounds capable of eliciting mitochondria-mediated apoptosis in cancer cells produced by medicinal fungi and plants. The medicinal fungi discussed encompass Cordyceps, Ganoderma species, Coriolus versicolor and Hypsizygus marmoreus. The medicinal plants discussed comprise Astragalus complanatus, Dendrobium spp, Dioscorea spp, Glycyrrhiza spp, Panax notoginseng, Panax ginseng, and Momordica charantia. These compounds have the potential of development into anticancer drugs.
Archive | 2018
Tzi Bun Ng; Jack Ho Wong; Chit Tam; Fang Liu; Chi F. Cheung; Charlene C.W. Ng; Ryan Tse; Tak Fu Tse; Helen Chan
Abstract Methyl gallate is an antioxidant found in a great variety of plant species including some edible beans and also mushrooms. It protects a diversity of cells including liver cells, kidney cells, heart cells, neuronal cells, and fat cells from oxidative stress induced by chemicals such as hydrogen peroxide. It upregulates antioxidant enzymes. It inhibits three key enzymes crucial to the HIV life cycle including reverse transcriptase, protease, and integrase. Methyl gallate inhibits HIV-1 replication in pseudovirus-infected TZM-BL cells.
Current Medicinal Chemistry | 2018
Randy Chi Fai Cheung; Tzi Bun Ng; Jack Ho Wong; Ryno J. Naudé; Krzysztof Rolka; Tak Fu Tse; Helen Chan; Ryan Tse; Stephen Cho Wing Sze
Lectins are a group of proteins or glycoproteins with various potentially exploitable bioactivities and have been capturing more interest recently. They have been isolated and reported from various tissues of a diversity of plant species. Tubers are modified and enlarged plant structures derived from stems or roots that are used for nutrient storage and asexual reproduction. A number of plants such as yam, taro and potato are grown for their edible tubers, and lectins are found to be one of the major storage proteins. These lectins exhibit potent bioactivities encompassing mitogenic, antitumor, antimicrobial, immunomodulatory, antioxidative, hypoglycemic, insecticidal and nematicidal activities. They are potential resources for development into functional or healthy foods and targets for food protein researchers.
Life Sciences | 2004
Clara Bik-San Lau; Cheong-Yip Ho; Chi-Fai Kim; K.N. Leung; Kwok-Pui Fung; T.F Tse; Helen Chan; Moses S. S. Chow
International Immunopharmacology | 2004
Cheong-Yip Ho; Clara Bik-San Lau; Chi-Fai Kim; K.N. Leung; Kwok-Pui Fung; Tak-Fu Tse; Helen Chan; Moses S. S. Chow
Virology | 1994
Eric B. Carstens; Helen Chan; Hans Yu; Greg V. Williams; Richard Casselman
Oncology Reports | 2006
Cheong-Yip Ho; Chi-Fai Kim; K.N. Leung; Kwok-Pui Fung; Tak-Fu Tse; Helen Chan; Clara Bik-San Lau
Archive | 2006
Helen Chan; Clara Bik-San Lau; Moses S. S. Chow
Archive | 2006
Helen Chan; Clara Bik-San Lau; Moses S. S. Chow