[Effect of starvation-induced autophagy on cell cycle of tumor cells].
OBJECTIVE
No serum starvation could induce autophagy and cell cycle arrest. Although autophagy and cell cycle have been widely explored, little is known about their relationship. This study was to observe the change of Cyclin expression during starvation-induced autophagy to discuss the effect of autophagy on cell cycle.


METHODS
In control group, HeLa cells were treated with d-Hanks solution (a medium with no serum). In experiment group, HeLa cells were treated with d-Hanks solution containing 3-methyladenine (3-MA, a specific inhibitor of autophagy). Cells were harvested after being starved for 0, 3, 6 and 12 h. Flow cytometry (FCM) and Weston blot were used to detect Cyclin and microtubule-associated protein 1 light chain 3(LC-3) which marked autophagy specifically.


RESULTS
In control group, the expression of LC-3 protein was detected early after being starved for 3 h, and gradually increased along with starvation; the expression of Cyclin D3 and Cyclin E was decreased evidently after a short-time starvation (3 h) and descended to the minimum when cells were being starved for 6 h; the expression of Cyclin A and Cyclin B1 were apparently decreased after being starved for 6 h. In experiment group, LC-3 protein could not be detected during starvation when cells were exposed to 3-MA and the down-regulation of Cyclins was suppressed.


CONCLUSIONS
Autophagy is involved in starvation-induced hydrolysis of Cyclins. The hydrolysis of Cyclin D3 and Cyclin E is quicker than that of Cyclin A and Cyclin B1.
Ge
Jun-Na
JN
Department of Gastrointestinal Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P. R. China.
Huang
Dan
D
Xiao
Tian
T
Wang
Zun
Z
Li
Xiao-Lan
XL
Xiao
Hui
H
Tao
De-Ding
DD
Gong
Jian-Ping
JP
D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects*; D019925:Cyclin A / Q000378:metabolism; D056744:Cyclin B1 / Q000378:metabolism; D056743:Cyclin D3 / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism*; D015536:Down-Regulation; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D008869:Microtubule-Associated Proteins / Q000378:metabolism
D019925:Cyclin A; D056744:Cyclin B1; D056743:Cyclin D3; D019927:Cyclin E; D016213:Cyclins; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; C025946:3-methyladenine; D000225:Adenine