PNAS-4, an Early DNA Damage Response Gene, Induces S Phase Arrest and Apoptosis by Activating Checkpoint Kinases in Lung Cancer Cells.
PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Our previous study has shown that PNAS-4 induces S phase arrest and apoptosis when overexpressed in A549 lung cancer cells. However, the underlying action mechanism remains far from clear. In this work, we found that PNAS-4 expression in lung tumor tissues is significantly lower than that in adjacent lung tissues; its expression is significantly increased in A549 cells after exposure to cisplatin, methyl methane sulfonate, and mitomycin; and its overexpression induces S phase arrest and apoptosis in A549 (p53 WT), NCI-H460 (p53 WT), H526 (p53 mutation), and Calu-1 (p53(-/-)) lung cancer cells, leading to proliferation inhibition irrespective of their p53 status. The S phase arrest is associated with up-regulation of p21(Waf1/Cip1) and inhibition of the Cdc25A-CDK2-cyclin E/A pathway. Up-regulation of p21(Waf1/Cip1) is p53-independent and correlates with activation of ERK. We further showed that the intra-S phase checkpoint, which occurs via DNA-dependent protein kinase-mediated activation of Chk1 and Chk2, is involved in the S phase arrest and apoptosis. Gene silencing of Chk1/2 rescues, whereas that of ATM or ATR does not affect, S phase arrest and apoptosis. Furthermore, human PNAS-4 induces DNA breaks in comet assays and γ-H2AX staining. Intriguingly, caspase-dependent cleavage of Chk1 has an additional role in enhancing apoptosis. Taken together, our findings suggest a novel mechanism by which elevated PNAS-4 first causes DNA-dependent protein kinase-mediated Chk1/2 activation and then results in inhibition of the Cdc25A-CDK2-cyclin E/A pathway, ultimately causing S phase arrest and apoptosis in lung cancer cells.
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China, yuanzhu@scu.edu.cn.
Zhu
Z
Yuan
the Department of Abdominal Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, No. 37, Guoxue Road, Chengdu 610041, Sichuan Province, China, and.
Wenhao
W
Guo
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Jun
J
Yang
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Lei
L
Li
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Meiliang
M
Wang
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Yi
Y
Lei
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Yang
Y
Wan
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Xinyu
X
Zhao
the Nankai University School of Medicine/Collaborative Innovation Center of Biotherapy, Tianjin 300071, China.
Na
N
Luo
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Ping
P
Cheng
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Xinyu
X
Liu
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Chunlai
C
Nie
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Yong
Y
Peng
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China, aipingtong@scu.edu.cn.
Aiping
A
Tong
From the State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, 17 People's South Road, Chengdu 610041, China.
Yuquan
Y
Wei
D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins / Q000502:physiology; D001483:Base Sequence; D019759:Carbon-Nitrogen Lyases; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2 / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D017931:DNA Primers; D004789:Enzyme Activation; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016196:S Phase / Q000502:physiology*
D051017:Apoptosis Regulatory Proteins; D017931:DNA Primers; D034741:RNA, Small Interfering; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D019759:Carbon-Nitrogen Lyases; C000604991:DESI2 protein, human
DNA damage response; PNAS-4; S phase arrest; apoptosis; cell cycle; checkpoint control; checkpoint kinase; lung cancer