Xu Shang-Zhi
Department of Pulmonary & Critical Care Medicine, College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, USA.
Int J Biomed Sci. 2010 Mar;6(1):49-59.
The homeobox transcription factor Prox1 plays an important role in the development of many embryonic organs. Previous studies indicated that Prox1 facilitates hepatic progenitor-cells proliferation. However, the underlying mechanism of Prox1 in tumor genesis, formation, and progression are poorly understood and need to be exploited. Herein, Chinese Hamster Ovary (CHO) cells were transfected and over-expressed human recombinant Prox1 gene, and developed several stable cell lines of Prox1-CHO after screening. The results indicated that over expression of Prox1 increased CHO cell proliferation in comparison to GFP-CHO and parental CHO cells, and Prox1 increased AKT phosphorylation and up-regulated PI3 Kinase expression. An AKT specific inhibitor-AKTi-X (5 μM) and a PI3 K inhibitor-LY294002 (5 μM) were able to reverse AKT phosphorylation and PI3 K expression induced by Prox1, respectively. Furthermore, AKTi-X but LY-294002 decreased Prox1-CHO cell proliferations at 48 and 72 h. Our results suggest that over expression of Prox1 facilitates CHO cell proliferation via activation of the AKT signaling pathway. This finding provides new insights into the mechanism of Prox1 mediated tumor growth and metastasis where Prox1 is rich.
同源框转录因子Prox1在许多胚胎器官的发育中起着重要作用。先前的研究表明,Prox1促进肝祖细胞增殖。然而,Prox1在肿瘤发生、形成和进展中的潜在机制尚不清楚,需要进一步探索。在此,将中国仓鼠卵巢(CHO)细胞转染并过表达人重组Prox1基因,经筛选后建立了几种Prox1-CHO稳定细胞系。结果表明,与GFP-CHO和亲本CHO细胞相比,Prox1的过表达增加了CHO细胞的增殖,并且Prox1增加了AKT磷酸化并上调了PI3激酶的表达。一种AKT特异性抑制剂AKTi-X(5 μM)和一种PI3 K抑制剂LY294002(5 μM)能够分别逆转Prox1诱导的AKT磷酸化和PI3 K表达。此外,AKTi-X可降低Prox1-CHO细胞在48小时和72小时的增殖,但LY-294002无此作用。我们的结果表明,Prox1的过表达通过激活AKT信号通路促进CHO细胞增殖。这一发现为Prox1介导的肿瘤生长和转移机制提供了新的见解,而Prox在肿瘤中大量存在。