title: Novel tamoxifen derivative Ridaifen-B induces Bcl-2 independent autophagy without estrogen receptor involvement.
abstract: Autophagy is a self-proteolysis process in eukaryotic cells that results in the sequestering of intracellular proteins and organelles in autophagosomes. Activation of autophagy progress continued growth of some tumors, instead extensive autophagy induces cell death. In a previous study, we synthesized a novel tamoxifen derivative, Ridaifen (RID)-B. RID-B induced mitochondria-involved apoptosis even in estrogen receptor (ER)-negative cells. Since tamoxifen induces autophagy other than apoptosis, we treated ER-negative Jurkat cells with RID-B in the present study. RID-B treatment induced apoptosis and LC3 and lysosome colocalization, which results in the formation of autolysosomes. Western blotting revealed that LC3 was converted to LC3-I to LC3-II with RID-B treatment, suggesting that RID-B induced autophagy without ER involvement. Moreover, overexpression of the anti-apoptotic protein Bcl-2 suppressed the RID-B-induced cell death, but not the induction of autophagy. These results presumed that RID-B-induced autophagy is independent of Bcl-2, making RID-B-induced autophagy different from RID-B-induced apoptosis. Since Beclin 1 level is unchanged during RID-B treatment, RID-B induced autophagy pathway is Bcl-2/Beclin1 independent noncanonical pathway.
authors.affiliation: Department of Biotechnology, College of Science and Engineering, Tokyo Denki University, Hatoyama, Hiki-gun, Saitama 350-0394, Japan. yuki@mail.dendai.ac.jp
authors.forename: Yukitoshi
authors.initials: Y
authors.lastname: Nagahara
authors.forename: Midori
authors.initials: M
authors.lastname: Takeyoshi
authors.forename: Seiya
authors.initials: S
authors.lastname: Sakemoto
authors.forename: Isamu
authors.initials: I
authors.lastname: Shiina
authors.forename: Kenya
authors.initials: K
authors.lastname: Nakata
authors.forename: Keiko
authors.initials: K
authors.lastname: Fujimori
authors.forename: Yanwen
authors.initials: Y
authors.lastname: Wang
authors.forename: Eri
authors.initials: E
authors.lastname: Umeda
authors.forename: Chihiro
authors.initials: C
authors.lastname: Watanabe
authors.forename: Shoko
authors.initials: S
authors.lastname: Uetake
authors.forename: Takao
authors.initials: T
authors.lastname: Yamori
authors.forename: Shingo
authors.initials: S
authors.lastname: Dan
authors.forename: Yoji
authors.initials: Y
authors.lastname: Yoshimi
authors.forename: Takahisa
authors.initials: T
authors.lastname: Shinomiya
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikekita
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage; D001343:Autophagy / Q000187:drug effects*; D006801:Humans; D019169:Jurkat Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D011759:Pyrrolidines / Q000008:administration & dosage*; D011960:Receptors, Estrogen / Q000378:metabolism*; D013629:Tamoxifen / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D019253:Proto-Oncogene Proteins c-bcl-2; D011759:Pyrrolidines; D011960:Receptors, Estrogen; C528171:ridaifen-B; D013629:Tamoxifen