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Regulation of [12Asp]K-ras4B on transcriptional activity of estrogen receptor in endometrial carcinoma HEC-1A cell lines

Gui, Liming, Wei, L. H., Xu, M. X., Wang, J. L., Zhong, Y. C., Li, X. P., Tu, Z., Sun, P. M. and Ma, D. L. 2004. Regulation of [12Asp]K-ras4B on transcriptional activity of estrogen receptor in endometrial carcinoma HEC-1A cell lines. Zhonghua fu chan ke za zhi 39 (1) , pp. 30-34.

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Abstract

OBJECTIVE: To investigate the effect of mutant-type [(12)Asp]K-ras4B gene on the expression of estrogen receptor (ER) alpha and beta and their transcriptional activity as a transcription factor in endometrial carcinoma HEC-1A cell line. METHODS: (1) Effect of [(12)Asp]K-ras4B on the expression of ER alpha and beta were determined using Western blot assay. (2) Eukaryotic expression plasmid pGL3-luciferase-ERE containing luciferase report gene and estrogen receptor element (ERE) was constructed, and co-transfected into NIH3T3 and HEC-1A cell lines with pEGFP-N1 to examine the effect of [(12)Asp]K-ras4B on ER transcription that is regulated by estradiol. In addition, they were transfected into pSV5-HER0 (containing full length wide type ERalpha cDNA) and pCMV-rafS621A (inhibiting raf kinase) plasmids to test the effect of [(12)Asp]K-ras4B/raf signal pathway on transcriptional activity of ER proteins. RESULTS: (1) Protein level of ERs expressed in pcDI transfected control cells was low while it was increased for 3.6-fold (97 +/- 25, 349 +/- 67, P < 0.01) and 1.9-fold (128 +/- 37, 349 +/- 30, P < 0.05) in ERalpha and ERbeta, respectively, in pcDI-[(12)Asp]K-ras4B NIH3T3 cells after transfection. (2) In pcDI-[(12)Asp]K-ras4B NIH3T3 cells, the ratios for ERalpha and and ERbeta levels before transfection of rafS621A plasmids to that after the transfection, were 2.4:1 (724 +/- 45, 310 +/- 46, P < 0.05) and 1.8:1 (493 +/- 20, 284 +/- 20, P < 0.01), respectively; In HEC-1A cells, these ratios were 2.1:1 (566 +/- 22, 279 +/- 30, P < 0.01) and 2.4:1 (405 +/- 33, 165 +/- 15, P < 0.01), respectively. (3) In low serum (2%) culture condition, estradiol (E(2)) stimulated luciferase activity with an increase of 13-fold (130 +/- 42, 1681 +/- 242, P < 0.01) in pcDI-[(12)Asp] K-ras4B NIH3T3 cells, 19-fold (141 +/- 39, 2644 +/- 331, P < 0.001) in HEC-1A cells, respectively, when compared with those in the absence of E(2). (4) In pSV5-HER0 transfected pcDI-[(12)Asp] K-ras4B NIH3T3 cells and HEC-1A cells, compared to the untransfected cells, the ER transcriptional activity in the transfected cells increased markedly. The luciferase activity was increased for 8-fold (1048 +/- 91, 8099 +/- 452, P < 0.01) and 6-fold (2148 +/- 259, 12,705 +/- 2670, P < 0.001), respectively. rafS621A mutant had suppressive effects on luciferase activities in HEC-1A cells and pcDI-[(12)Asp]K-ras4B NIH3T3 cells. The ratio of luciferase activities in pcDI-[(12)Asp]K-ras4B NIH3T3 and HEC-1A cells, before and after transfection was 7.8:1 (1184 +/- 168, 152 +/- 27, P < 0.05) and 6.4:1 (1949 +/- 212, 304 +/- 60, P < 0.01), respectively. CONCLUSIONS: (1) [(12)Asp]K-ras4B can enhance the expression of ERalpha and beta proteins. This may be correlated with [(12)Asp]K-ras4B/raf signaling pathway. (2) The effect of mutant-type [(12)Asp]K-ras4B gene on ERs transcriptional activity in HEC-1A cells appears to need E(2).

Item Type: Article
Date Type: Publication
Status: Published
Schools: Biosciences
Related URLs:
Last Modified: 28 Jun 2019 02:03
URI: https://orca.cardiff.ac.uk/id/eprint/71178

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