Analysis of expression of chorionic gonadotrophin transcripts in prostate cancer by quantitative Taqman and a modified molecular beacon RT-PCR

Abstract

Expression of human chorionic gonadotrophin (hCG) is associated with trophoblastic, testicular and other malignancies such as bladder, pancreatic, cervical, breast and prostate cancer. In the prostate, however, hCG expression, associated with neuroendocrine cells, is also found in normal tissue. Of the six highly homologous genes that all encode the -subunit of hCG, the 7 gene is reportedly the only gene expressed in several non-transformed tissues. The 3, 5 and 8 genes would be variably expressed in malignant tissue and placenta, but not in normal tissue. To assess to what extent this expression difference can also be found in the prostate, we compared the levels of the different hCG transcripts in concurrent normal and cancerous prostate tissues obtained from 17 patients. To this end, we developed a Taqman real-time fluorescent RT-PCR assay for hCG , and a quantitative assay specific for the 3, 5 and 8 genes, modified from the molecular beacon principle. This latter assay proved highly specific and capable of reliably distinguishing between these hCG transcripts that differ in only one nucleotide. Surprisingly, median expression levels of hCG were lower in prostate cancer when compared with normal tissue from the same patient. In contrast, hCG 3, 5 and 8 transcripts were found in normal tissue and did not differ in prostate cancer, arguing against a specific role of these transcripts in the development of prostate cancer.

Expression Of Human Chorionic Gonadotropin β-Subunit Type I Genes Predicts Adverse Outcome In Renal Cell Carcinoma

“…35 Based on these findings, malignant transformation has been thought to be associated with type II hCG␤ expression. However, earlier studies on RCC cell lines have shown a higher proportion (50 to 85%) of type I hCG␤ genes, 36 and in the present study, we detected type II gene expression in only two of the 42 positive tumors. Thus, expression of the various hCG␤ genes is both tissue and tumor specific, and aggressive tumor growth may be associated with increased expression of either gene type.…”

“…18,35,36 Type II genes are expressed in breast cancer tissue, 17 and increased expression of type II genes has been found to be associated with advanced stage in bladder cancer. 35 Based on these findings, malignant transformation has been thought to be associated with type II hCG␤ expression.…”

Molecular Beacon Reverse Transcription-PCR of Human Chorionic Gonadotropin-β-3, -5, and -8 mRNAs Has Prognostic Value in Breast Cancer

“…However, to obtain a smaller loop sequence, only one arm (shown in italics in the sequence above), complementary to five nucleotides at the 5Ј end of the hCG␤ sequence, was attached 3Ј (6,14 ). This produced a Molecular Beacon-type probe with excellent specificity for hCG␤-3, -5, and -8 mRNA without interference by transcripts from the hCG␤-7 or luteinizing hormone genes (6 ). PCR primers were designed with use of the Primer Express Software (PE Applied Biosystems).…”

“…Other malignancies, such as bladder (3,4 ), pancreatic, and cervical carcinomas (3 ) and prostate (5,6 ) and breast cancer (7)(8)(9)(10), also express hCG. This hormone is one of a family of related glycoproteins that includes luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone.…”

Technique and method development for intervertebral disc (IVD) research

“…There were also a number of studies by other groups using Taqman based gene expression analysis with RNA extracted with TRIzol reagent [156][157][158][159][160][161][162] …”