title: Isoprenoid-independent pathway is involved in apoptosis induced by risedronate, a bisphosphonate, in which Bim plays a critical role in breast cancer cell line MCF-7.
abstract: Bisphosphonates cause apoptosis to various types of cancer cells including breast cancer. Inhibition of the mevalonate pathway was reported to be involved in the apoptosis induced by bisphosphonates, but its precise mechanism has not been unveiled. In the present study, we investigated the molecular mechanism of risedronate, a bisphosphonate, in the apoptosis of the breast cancer cell line MCF-7 in comparison with that of cerivastatin, an HMG CoA reductase inhibitor (statin), since statin has been known to induce apoptosis through an isoprenoid-dependent pathway in these cells. We found that i) risedronate induced MCF-7 cells into apoptosis in a manner similar to cerivastatin with the activation of caspase-9 followed by caspase-6 and -7, that ii) bisphosphonate-induced apoptosis was significantly, but not fully, recovered by the addition of GGOH, an isoprenoid, which completely rescued in case of cerivastatin-induced apoptosis, that iii) risedronate induced G2 arrest with the induction of Bim (BH3-only protein), but that statin induced G1 arrest without it, and that iv) the down-regulation of Bim protein by siRNA significantly attenuated the risedronate-induced apoptosis. These data clearly indicate that both isoprenoid-dependent and -independent pathways might be involved in the apoptosis induced by bisphosphonate, and Bim might be a critical component for the isoprenoid-independent apoptotic pathway.
authors.affiliation: Department of Clinical Cell Biology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Suyama
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yoshida
authors.forename: Takahisa
authors.initials: T
authors.lastname: Shibata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Saito
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tatsuno
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D000068296:Risedronic Acid; D015398:Signal Transduction / Q000187:drug effects*; D013729:Terpenes / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; D050071:Bone Density Conservation Agents; D002121:Calcium Channel Blockers; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011725:Pyridines; D034741:RNA, Small Interfering; D013729:Terpenes; C086276:cerivastatin; D020169:Caspases; D000068296:Risedronic Acid; D012968:Etidronic Acid