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Cyclin‐dependent kinase inhibitor, flavopiridol, induces apoptosis and inhibits tumor growth in drug‐resistant osteosarcoma and Ewing's family tumor cells
Author(s) -
Li Yan,
Tanaka Kazuhiro,
Li Xu,
Okada Takamitsu,
Nakamura Tomoyuki,
Takasaki Minoru,
Yamamoto Shunsaku,
Oda Yoshinao,
Tsuneyoshi Masazumi,
Iwamoto Yukihide
Publication year - 2007
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.22820
Subject(s) - cancer research , apoptosis , cyclin dependent kinase , poly adp ribose polymerase , caspase 3 , biology , kinase , caspase , cyclin d , cell cycle , programmed cell death , biochemistry , polymerase , enzyme
Multimodal therapies play important roles in the treatment of osteosarcoma (OS) and Ewing's family of tumors (EFTs), two most frequent malignant bone tumors. Although the clinical outcome of primary OS and EFTs is greatly improved, the relapsed cases often are associated with multidrug resistance of the tumors and the prognosis of these patients is still poor. Flavopiridol, a pan cyclin‐dependent kinase (CDK) inhibitor is a novel antitumor agent that can induce cell cycle arrest and apoptosis in many cancer cells. However, there have been no studies about the effects of flavopiridol on drug‐resistant OS and EFTs. Here, we demonstrated that flavopiridol induced the cleavage of poly‐ADP‐ribose polymerase (PARP) in a time and dose dependent manner in adriamycin‐resistant OS and EFTs cells expressing P‐glycoprotein (P‐gp) and multidrug resistance‐associated protein 1 (MRP 1 ) as effectively as in their parental cells. Our data also showed that flavopiridol caused the release of mitochondrial cytochrome c and the activation of caspase‐9, caspase‐8 and caspase‐3, with an increase ratio of the proapoptotic protein level (Bax) to the antiapoptotic protein level (Bcl‐2 and Bcl‐X L ), while apoptosis was inhibited by pan caspase inhibitor (Z‐VAD‐FMK) and caspase‐3 inhibitor (Z‐DEVD‐FMK), not by caspase‐8 inhibitor (Z‐IETD‐FMK). The treatment with flavopiridol further inhibited the tumor growth in mouse models of the drug‐resistant OS and EFTs. These results suggest that flavopiridol might be promising in clinical therapy for the relapsed OS and EFTs. © 2007 Wiley‐Liss, Inc.