[Hic-5/ARA55 inhibits the growth of Lovo cells by up-regulating the expression of P27].
OBJECTIVE
To investigate the effects of Hic-5/ARA55 on the growth of the human colorectal cancer cells (Lovo cells) and its mechanism.


METHODS
Flow cytometry (FCM) was used to study the cell cycle of Lovo cells (Lovo group), Lovo cells stably transfected with empty vector (Lovo-Vector group) and the Lovo cells stably transfected with vector containing Hic-5/ARA55 (Lovo-Hic-5/ARA55 group). Western blot assay was used to detect the principal cyclins in the three groups, and Luciferase assay was used to study the mechanism between Hic-5/ARA55 and the only target cyclin. The cells from the three groups were inoculated subcutaneously into 7 nude mice (Balb/c nu/nu) respectively to observe the effects of Hic-5/ARA55 on the growth of the cells in vivo. Seven weeks later, the subcutaneous tumors were harvested and weighed. Then immunohistochemistry assay was used to detect Hic-5/ARA55 and the target cyclin in the tumors.


RESULTS
The cell cycle was obviously delayed from G0/G1 to S stage in Lovo-Hic-5/ARA55 cells. A significantly higher expression of P27 was found in Lovo-Hic-5/ARA55 cells than in the other two groups. The weight of the subcutaneous tumors of Lovo-Hic-5/ARA55 cells, Lovo cells and Lovo-Vector cells were (0.33 +/- 0.23) g, (1.20 +/- 0.39) g and (1.30 +/- 0.49) g, respectively; the tumors of Lovo-Hic-5/ARA55 cells was significantly lighter than those of the other two groups (P<0.05). Hic-5/ARA55 and P27 were both over-expressed in implanted tumors of Lovo-Hic-5/ARA55 cells, while were both expressed lower or not expressed in the other two groups. And the expressions of Hic-5/ARA55 and P27 were highly positive correlated (r=0.816, P<0.05).


CONCLUSIONS
Hic-5/ARA55 could inhibit the growth of Lovo cells both in vitro and in vivo by up-regulating the transcription of P27.
Wu
Ying-chao
YC
Department of General Surgery, Peking University First Hospital, Beijing 100034, China.
Wang
Xin
X
Liu
Yu-cun
YC
Wan
Yuan-lian
YL
Zhu
Jing
J
D000818:Animals; D002453:Cell Cycle; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D008819:Mice, Nude; D010957:Plasmids / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D050760:Cyclin-Dependent Kinase Inhibitor p27