Modulation of bcl-2 family proteins in MAPK independent apoptosis induced by a cdc25 phosphatase inhibitor Cpd 5 in renal cancer cells.
Protein phosphatases have been classified into two basic types, namely protein serine/threonine phosphatase (PP), and protein tyrosine phosphatase (PTP). Cpd 5 is a selective inhibitor of cdc25 phosphatases, which belong to members of PTPs and regulate cell proliferation by controlling cyclin-dependent kinases (cdks). The present study was undertaken to investigate the potential utility of Cpd 5 as an anti-neoplastic agent for renal cell carcinomas (RCCs). Three renal cancer cell lines, 769P, Sw839, and A498 were used. The effects of Cpd 5 on the viability of renal cancer cell lines was analyzed using an Alamar Blue assay. Apoptosis was determined by flow cytometric TUNEL analysis. Changes in the expression of cdc25 phosphatases, mitogen-activated protein kinases (MAPKs), and bcl-2 family proteins were detected using Western blot analysis. The apoptosis-inducing effect of Cpd 5 on human RCC tissue was analyzed through TUNEL staining of organ cultures from RCCs. Cpd 5 showed a strong cytotoxicity against all renal cancer cell lines with an apoptosis-inducing effect. All cell lines treated with Cpd 5 resulted in a down-regulation of cdc25A, cdc25B, and cdc25C, however, the MAPK pathways were not affected. In addition, the up-regulation of bax, and the down-regulation of bcl-2 and bcl-xL, was observed. In organ cultures from RCCs, TUNEL-positive apoptotic nuclei were observed when treated with Cpd 5. Cpd 5 was thus found to effectively inhibit the proliferation of human renal cancer cells while also inducing apoptosis by inhibiting cdc25 phosphatases and modulating bcl-2 family proteins. The administration of Cpd 5 may thus be an effective therapeutic approach for RCCs.
Mizuno
Ryuichi
R
Department of Urology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
Oya
Mototsugu
M
Hara
Satoshi
S
Matsumoto
Mayuko
M
Horiguchi
Akio
A
Ohigashi
Takashi
T
Marumo
Ken
K
Murai
Masaru
M
D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D007680:Kidney Neoplasms / Q000378:metabolism / Q000473:pathology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D014812:Vitamin K / Q000031:analogs & derivatives* / Q000494:pharmacology; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D020687:cdc25 Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism
C446520:2-(2-hydroxyethylsulfanyl)-3-methyl-1,4-naphthoquinone; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D014812:Vitamin K; D020928:Mitogen-Activated Protein Kinases; D020687:cdc25 Phosphatases