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Zoledronate has an antitumor effect and induces actin rearrangement in dexamethasone‐resistant myeloma cells
Author(s) -
Koizumi Masayuki,
Nakaseko Chiaki,
Ohwada Chikako,
Takeuchi Masahiro,
Ozawa Shinichi,
Shimizu Naomi,
Cho Ryuko,
Nishimura Miki,
Saito Yasushi
Publication year - 2007
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2007.00957.x
Subject(s) - apoptosis , cell culture , rhoa , dexamethasone , geranylgeraniol , in vitro , prenylation , viability assay , chemistry , cancer research , pharmacology , microbiology and biotechnology , medicine , biology , biochemistry , signal transduction , enzyme , genetics
New strategies are needed to overcome the resistance of multiple myeloma (MM) to dexamethasone (Dex). Several recent in vitro studies demonstrated the antitumor effect of nitrogen‐containing amino‐bisphosphonates (N‐BPs) in various tumor cell lines. Inhibition of the prenylation of small G proteins is assumed to be one of the principal mechanisms by which N‐BPs exert their effects. There have been few reports on N‐BP treatment of MM cells that are resistant to Dex. Additionally, it is not known how small G proteins are altered in N‐BP‐treated MM cells. In this study, we evaluated the effect of the most potent N‐BP, zoledronate (ZOL), on a Dex‐resistant human MM cell subline (Dex‐R) that we established from the well‐documented RPMI8226 cell line. ZOL reduced the viability and induced apoptosis of Dex‐R cells. Some of the ZOL‐treated RPMI8226 cells and ZOL‐treated Dex‐R cells were elongated; however, elongated cells were not seen among the Dex‐treated RPMI8226 cells. Furthermore, we found that portions of the small G proteins, Rho and Rap1A, were unprenylated in the ZOL‐treated MM cells. Geranylgeraniol reduced the above‐mentioned ZOL‐induced effects. These findings suggest that ZOL may be beneficial for the treatment of Dex‐resistant MM by suppressing the processing of RhoA and Rap1A.