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Title: G{sub 1} arrest and down-regulation of cyclin E/cyclin-dependent kinase 2 by the protein kinase inhibitor staurosporine are dependent on the retinoblastoma protein in the bladder carcinoma cell line 5637

Abstract

The protein kinase inhibitor staurosporine has been shown to induce G{sub 1} phase arrest in normal cells but not in most transformed cells. Staurosporine did not induce G{sub 1} phase arrest in the bladder carcinoma cell line 5637 that lacks a functional retinoblastoma protein (pRB{sup {minus}}). However, when infected with a pRB-expressing retrovirus, these cells, now pRB{sup +} and pRB{sup {minus}} cells, cyclin D1-associated kinase activities were reduced on staurosporine treatment. In contrast, cylin-dependent kinase (CDK) 2 and cyclin E/CDK2 activities were inhibited only in pRB{sup +} cells. Staurosporine treatment did not cause reductions in the protein levels of CDK4, cyclin D1, CDK2, or cyclin E. The CDK inhibitor proteins p21{sup (Wafl/Cipl)} and p27{sup (Kipl}) levels increased in staurosporine-treated cells. Immunoprecipitation of CDK2, cyclin E, and p21 form staurosporine-treated pRB{sup +} cells revealed a 2.5- to 3-fold higher ratio of p21 bound to CDK2 compared with staurosporine-treated pRB cells. In pRB{sup +} cells, p21 was preferentially associated with Thr160 phosphorylated active CDK2. In pRB{sup {minus}} cells, however, p21 was bound preferentially to the unphosphorylated, inactive form of CDK2 even though the phosphorylated form was abundant. This is the first evidence suggesting that G{sub 1} arrest by 4 nM staurosporine ismore » dependent on a functional pRB protein. Cell cycle arrest at the pRB-dependent checkpoint may prevent activation of cyclin E/CDK2 by stabilizing its interaction with inhibitor proteins p21 and p27. 47 refs.« less

Authors:
;  [1];  [2]
  1. Univ. of California, Davis, CA (United States)
  2. Univ. of Texas, Houston, TX (United States); and others
Publication Date:
OSTI Identifier:
457015
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Journal Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 93; Journal Issue: 12; Other Information: PBD: 11 Jun 1996
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; PHOSPHOTRANSFERASES; RESPONSE MODIFYING FACTORS; ENZYME INHIBITORS; TUMOR CELLS; BLADDER; NEOPLASMS

Citation Formats

Schnier, J B, Nishi, K, and Goodrich, D W. G{sub 1} arrest and down-regulation of cyclin E/cyclin-dependent kinase 2 by the protein kinase inhibitor staurosporine are dependent on the retinoblastoma protein in the bladder carcinoma cell line 5637. United States: N. p., 1996. Web. doi:10.1073/pnas.93.12.5941.
Schnier, J B, Nishi, K, & Goodrich, D W. G{sub 1} arrest and down-regulation of cyclin E/cyclin-dependent kinase 2 by the protein kinase inhibitor staurosporine are dependent on the retinoblastoma protein in the bladder carcinoma cell line 5637. United States. doi:10.1073/pnas.93.12.5941.
Schnier, J B, Nishi, K, and Goodrich, D W. Tue . "G{sub 1} arrest and down-regulation of cyclin E/cyclin-dependent kinase 2 by the protein kinase inhibitor staurosporine are dependent on the retinoblastoma protein in the bladder carcinoma cell line 5637". United States. doi:10.1073/pnas.93.12.5941.
@article{osti_457015,
title = {G{sub 1} arrest and down-regulation of cyclin E/cyclin-dependent kinase 2 by the protein kinase inhibitor staurosporine are dependent on the retinoblastoma protein in the bladder carcinoma cell line 5637},
author = {Schnier, J B and Nishi, K and Goodrich, D W},
abstractNote = {The protein kinase inhibitor staurosporine has been shown to induce G{sub 1} phase arrest in normal cells but not in most transformed cells. Staurosporine did not induce G{sub 1} phase arrest in the bladder carcinoma cell line 5637 that lacks a functional retinoblastoma protein (pRB{sup {minus}}). However, when infected with a pRB-expressing retrovirus, these cells, now pRB{sup +} and pRB{sup {minus}} cells, cyclin D1-associated kinase activities were reduced on staurosporine treatment. In contrast, cylin-dependent kinase (CDK) 2 and cyclin E/CDK2 activities were inhibited only in pRB{sup +} cells. Staurosporine treatment did not cause reductions in the protein levels of CDK4, cyclin D1, CDK2, or cyclin E. The CDK inhibitor proteins p21{sup (Wafl/Cipl)} and p27{sup (Kipl}) levels increased in staurosporine-treated cells. Immunoprecipitation of CDK2, cyclin E, and p21 form staurosporine-treated pRB{sup +} cells revealed a 2.5- to 3-fold higher ratio of p21 bound to CDK2 compared with staurosporine-treated pRB cells. In pRB{sup +} cells, p21 was preferentially associated with Thr160 phosphorylated active CDK2. In pRB{sup {minus}} cells, however, p21 was bound preferentially to the unphosphorylated, inactive form of CDK2 even though the phosphorylated form was abundant. This is the first evidence suggesting that G{sub 1} arrest by 4 nM staurosporine is dependent on a functional pRB protein. Cell cycle arrest at the pRB-dependent checkpoint may prevent activation of cyclin E/CDK2 by stabilizing its interaction with inhibitor proteins p21 and p27. 47 refs.},
doi = {10.1073/pnas.93.12.5941},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 12,
volume = 93,
place = {United States},
year = {1996},
month = {6}
}