Characterization of immortalized human ovarian surface epithelial cells transfected by PTEN expression vectors

上皮性卵巢癌被认为是由卵巢表面上皮（OSE）细胞覆盖的人卵巢的自由表面。两个永生化的人细胞系，OSE 2a（非致瘤性）和OSE 2b-2（致瘤性），以前建立从正常的OSE细胞的育龄患者。在本项目中，我们发现促黄体生成素（LH）/人绒毛膜促性腺激素（hCG）受体（R）在OSE 2a细胞中表达，而在OSE 2b-2细胞中不表达。在OSE 2a细胞中，低浓度（10^3 mIU/ml）的hCG通过上调胰岛素样生长因子-1（IGF 1）来增强锚定依赖性生长，而高浓度（10^5 mIU/ml）的hCG诱导锚定非依赖性生长和下调IGF 1表达。为了研究LH/hCG相关致瘤性中其他基因的参与，我们比较了OSE 2a和OSE 2b-2细胞之间的cDNA表达阵列，发现以下基因在OSE 2b-2中的表达低于OSE 2a：整合素β1，细胞间粘附分子1（ICAM 1）和Wafl/Cipl。随后使用OSE 2a细胞的半定量逆转录聚合酶链反应显示，整合素β1的表达被高浓度（10^5 mIU/ml）的hCG下调。这些结果表明，LH/CGR通过介导IGF 1和整合素β1的上调和下调来影响锚定依赖性和非依赖性生长。LH/hCGR的重复和过度激活可能导致其信号转导途径的遗传改变，从而刺激OSE细胞的生长，引发卵巢癌的发生和癌症的进展。我们已经向《癌症科学》提交了一份研究论文。关于PTEN基因，在研究PTEN表达载体转染永生化OSE细胞的特性之前，对LH/hCGR进行了功能分析。我们还将进一步研究PTEN的表达方案。

Epithelial ovarian carcinomas are thought to arise from cells of ovarian surface epithelium (OSE) covering the free surface of the human ovary. Two immortalized human cell lines, OSE2a (non-tumorigenic) and OSE2b-2 (tumorigenic), were previously established from normal OSE cells of a reproductive-age patient. In the present project, we found that expression of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptor (R) is present in OSE2a cells and absent in OSE2b-2 cells. In OSE2a cells, a low concentration (10^3 mIU/ml) of hCG enhanced anchorage-dependent growth via up-regulation of insulin-like growth factor-1 (IGF1), whereas a high concentration (10^5 mlU/ml) of hCG induced anchorage-independent growth and down-regulation of IGF1 expression. To investigate involvement of other genes in LH/hCGR-related tumorigenicity, we compared cDNA expression arrays between OSE2a and OSE2b-2 cells, and found that the following genes had lower expression in OSE2b-2 than in OSE2a: integrin β1, intercellular adhesion molecule-1 (ICAM1), and Wafl/Cipl. Subsequent semiquantitative reverse transcription porymerase chain reaction using OSE2a cells showed that expression of integrin β1 was down-regulated by a high concentration (10^5 mlU/ml) of hCG. These results suggest that LH/CGR affects anchorage-dependent and -independent growth by mediating up- and down-regulation of IGF1 and integrin β1. Repetitive and excessive activation of LH/hCGR may cause genetic alteration of its signal transduction pathway, resulting in stimulation of growth of OSE cells, initiation of ovarian carcinogenesis, and cancer progression. We have submitted a manuscript for this study to 'Cancer Science'.Regarding the PTEN gene, the functional analysis of LH/hCGR preceded the study for characterization of immortalized OSE cells trasfected by PTEN expression vectors. We still farther study the project for the PTEN expression.