TY - JOUR
T1 - Protective function of p27 KIP1 against apoptosis in small cell lung cancer cells in unfavorable microenvironments
AU - Masuda, Akira
AU - Osada, Hirotaka
AU - Yatabe, Yasushi
AU - Kozaki, Ken Ichi
AU - Tatematsu, Yoshio
AU - Takahashi, Takao
AU - Hida, Toyoaki
AU - Takahashi, Toshitada
AU - Takahashi, Takashi
N1 - Funding Information:
Supported in part by a grant-in-aid for Scientific Research on Priority Areas and a grant-in-aid for Scientific Research (C) from the Ministry of Education, Science, Sports, and Culture, Japan; a grant-in-aid for the Second Term Comprehensive Ten-Year Strategy for Cancer Control from the Ministry of Health and Welfare, Japan; and by a grant from the Smoking Research Foundation.
PY - 2001/1
Y1 - 2001/1
N2 - A previous study of ours unexpectedly found that in contrast to frequent reductions in non-small cell lung cancer, high expression of the p27 KIP1 cyclin-dependent kinase (CDK) inhibitor was retained in virtually all small cell lung cancers (SCLCs), suggesting the possibility of high expression of nonfunctional p27 KIP1 in this virulent tumor. The study presented here, however, shows that p27 KIP1 in SCLC biochemically functions as a CDK inhibitor, clearly showing induction apparently associated with G 1 /G 0 arrest and efficient binding to and inhibition of the cyclin E-CDK2 complex. Interestingly, induction of p27 KIP1 seems to confer on SCLC cells the ability to survive under culture conditions unfavorable for cell growth such as a lack of nutrients and hypoxia. Subsequent experiments manipulating p27 KIP1 levels by using a sense p27 KIP1 expression construct or an antisense oligonucleotide supported this notion. These observations suggest that high expression of p27 KIP1 in vivo may favor the survival of SCLC by preventing apoptosis in a microenvironment unfavorable for cell proliferation.
AB - A previous study of ours unexpectedly found that in contrast to frequent reductions in non-small cell lung cancer, high expression of the p27 KIP1 cyclin-dependent kinase (CDK) inhibitor was retained in virtually all small cell lung cancers (SCLCs), suggesting the possibility of high expression of nonfunctional p27 KIP1 in this virulent tumor. The study presented here, however, shows that p27 KIP1 in SCLC biochemically functions as a CDK inhibitor, clearly showing induction apparently associated with G 1 /G 0 arrest and efficient binding to and inhibition of the cyclin E-CDK2 complex. Interestingly, induction of p27 KIP1 seems to confer on SCLC cells the ability to survive under culture conditions unfavorable for cell growth such as a lack of nutrients and hypoxia. Subsequent experiments manipulating p27 KIP1 levels by using a sense p27 KIP1 expression construct or an antisense oligonucleotide supported this notion. These observations suggest that high expression of p27 KIP1 in vivo may favor the survival of SCLC by preventing apoptosis in a microenvironment unfavorable for cell proliferation.
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U2 - 10.1016/S0002-9440(10)63947-8
DO - 10.1016/S0002-9440(10)63947-8
M3 - Article
C2 - 11141482
AN - SCOPUS:0035144958
VL - 158
SP - 87
EP - 96
JO - American Journal of Pathology
JF - American Journal of Pathology
SN - 0002-9440
IS - 1
ER -