Abnormal structure and expression ofPTEN/MMAC1 gene in human uterine cancers

Abstract

The PTEN/MMAC1 gene, located on human chromosome 10q23, has recently been implicated as a candidate tumor suppressor gene in human cancers. In the present study, 12 uterine cancer cell lines and 87 uterine cancers of various grades and histological type were analyzed for PTEN/MMAC1 gene. Three of 44 endometrial carcinoma (7%) showed no PTEN/MMAC1 mRNA expression by RT-PCR analysis. Sequencing analysis of entire coding region of PTEN/MMAC1 gene revealed mutations in three of six endometrial cancer cell lines (50%) and 17 of 44 endometrial cancer tissues (39%). In contrast, for cervical cancers, only one of six cancer cell lines (2%) showed mutation, and one of 43 cancer tissues (2%) had an abnormality. Overall, 36% of the abnormal spots were located in exon 5, 24% were in exon 8, 16% were in exon 3, and 8% were in exon 6, and single cases of abnormality were found in exons 1, 4, and 7. Our results revealed that, in total, 60% of abnormalities were clustered in exons 5 and 8. Exon 5 is a functional domain of the PEN/MMAC1 gene, and therefore, abnormalities in this region may be important for loss of PTEN/MMAC1 gene function. Finally, we found a high frequency of PTEN/MMAC1 gene abnormalities in endometrial carcinomas but a low frequency in cervical carcinomas. These findings suggest that disruption of PTEN/MMAC1 by mutation or absence of expression may contribute to the pathogenesis or neoplastic evolution in a large proportion of endometrial carcinomas but in a small proportion of cervical carcinomas.

Inhibition of AKT survival pathway by a small molecule inhibitor in human endometrial cancer cells

“…The same lysates were immunoprecipitated with anti-AKT antibody; AKT kinase assay was performed with GSK-3 as a substrate and phospho-specific GSK-3 α / β (Ser 21/9) for phosphorylated protein detection.). This is consistent with previous reports that Ishikawa and RL95-2 cell lines contain PTEN mutations, while Hec1A and KLE cells express wild-type PTEN (Yaginuma et al , 2000). We also found that Ishikawa and RL95-2 cell lines express high levels of phosphorylated AKT and have high AKT kinase activity, whereas Hec1A and KLE cells express little phosphorylated AKT and have undetectable AKT kinase activity (Figure 1).…”

“… ). This is consistent with previous reports that Ishikawa and RL95-2 cell lines contain PTEN mutations, while Hec1A and KLE cells express wild-type PTEN ( Yaginuma et al , 2000 ). We also found that Ishikawa and RL95-2 cell lines express high levels of phosphorylated AKT and have high AKT kinase activity, whereas Hec1A and KLE cells express little phosphorylated AKT and have undetectable AKT kinase activity ( Figure 1 ).…”

Effects of indomethacin on expression of PTEN tumour suppressor in human cancers

“…This is in agreement with previous studies, which reported that the HEC 1B cells express abundant amounts of the wild-type PTEN protein 2526. The PTEN mRNA has been previously reported to be present in fairly large amounts in all normal tissues studied, such as heart, lung, liver, muscle, kidney and pancreas 27.…”

Tumor Genetic Analyses of Patients with Metastatic Melanoma Treated with the BRAF Inhibitor Dabrafenib (GSK2118436)

“…In one patient, a mutation in PTEN was observed in the pre-treatment, but not archival sample. This mutation was the only one observed in PTEN , p.P95L, and has been previously reported in association with cancer (27–29). For four samples, we obtained only mutational, but not copy number data; these samples were removed from further analysis.…”