Role of insulin-like growth factor-1 (IGF-1) in regulating cell cycle progression.
OBJECTIVE
Insulin-like growth factor-1 (IGF-1) is a polypeptide protein hormone, similar in molecular structure to insulin, which plays an important role in cell migration, cell cycle progression, cell survival and proliferation. In this study, we investigated the possible mechanisms of IGF-1 mediated cell cycle redistribution and apoptosis of vascular endothelial cells.


METHODS
Human umbilical vein endothelial cells (HUVECs) were pretreated with 0.1, 0.5, or 2.5 microg/mL of IGF-1 for 30 min before the addition of Ang II. Cell cycle redistribution and apoptosis were examined by flow cytometry. Expression of Ang II type 1 (AT(1)) mRNA and cyclin E protein were determined by RT-PCR and Western blot, respectively.


RESULTS
Ang II (1 micromol/L) induced HUVECs arrested at G(0)/G(1), enhanced the expression level of AT(1) mRNA in a time-dependent manner, reduced the enzymatic activity of nitric oxide synthase (NOS) and nitric oxide (NO) content as well as the expression level of cyclin E protein. However, IGF-1 enhanced NOS activity, NO content, and the expression level of cyclin E protein, and reduced the expression level of AT(1) mRNA. L-NAME significantly counteracted these effects of IGF-1.


CONCLUSIONS
Our data suggests that IGF-1 can reverse vascular endothelial cells arrested at G(0)/G(1) and apoptosis induced by Ang II, which might be mediated via a NOS-NO signaling pathway and is likely associated with the expression levels of AT1 mRNA and cyclin E proteins.
Ma
Qi-lin
QL
Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, PR China.
Yang
Tian-lun
TL
Yin
Ji-ye
JY
Peng
Zhen-yu
ZY
Yu
Min
M
Liu
Zhao-qian
ZQ
Chen
Fang-ping
FP
D017209:Apoptosis; D002453:Cell Cycle / Q000187:drug effects; D019927:Cyclin E / Q000096:biosynthesis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology / Q000502:physiology*; D009569:Nitric Oxide / Q000032:analysis / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D044140:Receptor, Angiotensin, Type 1 / Q000096:biosynthesis
D019927:Cyclin E; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D019001:Nitric Oxide Synthase