title: Basic helix-loop-helix transcription factors DEC1 and DEC2 regulate the paclitaxel-induced apoptotic pathway of MCF-7 human breast cancer cells.
abstract: Differentiated embryonic chondrocyte gene (DEC) 1 (BHLHE40/Stra13/Sharp2) and DEC2 (BHLHE41/Sharp1) are basic helix-loop-helix (bHLH) transcription factors that are associated with the regulation of apoptosis, cell proliferation and circadian rhythms, as well as malignancy in various cancers. However, the roles of DEC1 and DEC2 expression in breast cancer are poorly understood. In this study, we sought to examine the roles of DEC1 and DEC2 in MCF-7 human breast cancer cells that had been treated with paclitaxel. The expression of DEC1 and DEC2 was up-regulated in paclitaxel-treated MCF-7 cells. Knockdown of DEC1 by siRNA decreased the amount of cleaved poly (ADP-ribose) polymerase (PARP), after treatment with paclitaxel, whereas DEC2 knockdown increased the amount of cleaved PARP in both the presence and absence of paclitaxel. Immunofluorescent staining revealed that paclitaxel treatment increased the amount of DEC1 in the nucleus, and increased the amount of DEC2 in both the nucleus and cytoplasm. These results indicate that DEC1 has pro-apoptotic effects, whereas DEC2 has anti-apoptotic effects on the paclitaxel-induced apoptosis in human breast cancer MCF-7 cells.
authors.affiliation: Department of Pathology and Bioscience, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Yunyan
authors.initials: Y
authors.lastname: Wu
authors.forename: Fuyuki
authors.initials: F
authors.lastname: Sato
authors.forename: Ujjal Kumar
authors.initials: UK
authors.lastname: Bhawal
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Mitsuhide
authors.initials: M
authors.lastname: Noshiro
authors.forename: Satoko
authors.initials: S
authors.lastname: Morohashi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kijima
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D001943:Breast Neoplasms / Q000503:physiopathology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D051792:Basic Helix-Loop-Helix Proteins; D017239:Paclitaxel; D034741:RNA, Small Interfering