title: Cytotoxic effect of ethanol extract of microalga, Chaetoceros calcitrans, and its mechanisms in inducing apoptosis in human breast cancer cell line.
abstract: Marine microalgae have been prominently featured in cancer research. Here, we examined cytotoxic effect and apoptosis mechanism of crude ethanol extracts of an indigenous microalga, Chaetoceros calcitrans (UPMAAHU10) on human breast cell lines. MCF-7 was more sensitive than MCF-10A with IC50 value of 3.00 ± 0.65, whilst the IC50 value of Tamoxifen against MCF-7 was 12.00 ± 0.52  μg/mL after 24 hour incubation. Based on Annexin V/Propidium iodide and cell cycle flow cytometry analysis, it was found that inhibition of cell growth by EEC on MCF-7 cells was through the induction of apoptosis without cell cycle arrest. The apoptotic cells at subG0/G1 phase in treated MCF-7 cells at 48 and 72 hours showed 34 and 16 folds increased compared to extract treated MCF-10A cells which showed only 6 and 7 folds increased at the same time points, respectively. Based on GeXP study, EEC induced apoptosis on MCF-7 cells via modulation of CDK2, MDM2, p21Cip1, Cyclin A2, Bax and Bcl-2. The EEC treated MCF-7 cells also showed an increase in Bax/Bcl-2 ratio that in turn activated the caspase-dependent pathways by activating caspase 7. Thus, marine microalga, Chaetoceros calcitrans may be considered a good candidate to be developed as a new anti-breast cancer drug.
authors.affiliation: Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Siyamak
authors.initials: S
authors.lastname: Ebrahimi Nigjeh
authors.forename: Fatimah Md
authors.initials: FM
authors.lastname: Yusoff
authors.forename: Noorjahan Banu
authors.initials: NB
authors.lastname: Mohamed Alitheen
authors.forename: Mehdi
authors.initials: M
authors.lastname: Rasoli
authors.forename: Yeap Swee
authors.initials: YS
authors.lastname: Keong
authors.forename: Abdul Rahman bin
authors.initials: AR
authors.lastname: Omar
mesh_terms: D017304:Annexin A5; D017209:Apoptosis / Q000187:drug effects*; D001688:Biological Products / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000473:pathology*; D002453:Cell Cycle; D049109:Cell Proliferation / Q000187:drug effects; D000431:Ethanol; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020128:Inhibitory Concentration 50; D061986:MCF-7 Cells; D058086:Microalgae / Q000737:chemistry*; D011419:Propidium; D012044:Regression Analysis; D013629:Tamoxifen / Q000494:pharmacology; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D017304:Annexin A5; D001688:Biological Products; D013778:Tetrazolium Salts; D013844:Thiazoles; D013629:Tamoxifen; D011419:Propidium; D000431:Ethanol; C022616:thiazolyl blue