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Consequences of antisense human chorionic gonadotrophin-alpha subunit cDNA expression in human choriocarcinoma JAR
1Department of Obstetrics and Gynecology, University of Louisville School of Medicine, Kentucky 40292, USA.
Abstract:
The biosynthesis of human chorionic gonadotrophin (hCG) is a hallmark endocrine function of human choriocarcinoma cells. The present study investigated the consequences of greatly diminishing this synthesis in JAR cells by stably transfecting them with pRSV-antisense hCG-alpha cDNA expression vector. The vector directs the synthesis of antisense hCG-alpha subunit mRNA which would then bind to sense hCG-alpha subunit mRNA, thus blocking its translation and consequently dimer hCG protein synthesis. The transfection with pRSV-antisense hCG-alpha cDNA resulted in a dramatic decrease in hCG secretion as compared with untransfected parental cells or those transfected with an empty vector used for the selection of clones. The decreased secretion was due to a decreased synthesis which in turn was due to a fall in steady-state hCG-alpha and -beta subunit mRNA levels. The decrease of hCG-beta subunit transcripts was unexpected and it was not due to contamination of antisense hCG-alpha cDNA construct with hCG-beta sequence. The transcription of hCG-alpha and -beta subunit genes was not altered in transfected cells suggesting that increased degradation was responsible for decreased steady-state hCG subunit mRNA levels. Despite the decreased hCG levels, the transfected cells maintained normal hCG receptor levels, responded to epidermal growth factor stimulation of hCG synthesis and secretion and grew at the same rate as the control parental cells and those transfected with an empty vector.
Insights
Researchers reduced human chorionic gonadotropin (hCG) synthesis in choriocarcinoma cells using antisense technology. This led to decreased hCG secretion and mRNA levels, without affecting cell growth or receptor expression.
Area of Science:
- Endocrinology
- Molecular Biology
- Cancer Research
Background:
- Human chorionic gonadotropin (hCG) biosynthesis is a key function of choriocarcinoma cells.
- Understanding hCG regulation is crucial for cancer research and therapeutic development.
Purpose of the Study:
- To investigate the effects of significantly reducing hCG synthesis in JAR choriocarcinoma cells.
- To explore the impact of antisense hCG-alpha cDNA transfection on hCG production and cellular functions.
Main Methods:
- Stable transfection of JAR cells with a pRSV-antisense hCG-alpha cDNA expression vector.
- Quantification of hCG secretion, subunit mRNA levels, gene transcription, and receptor expression.
- Comparison between transfected cells, parental cells, and empty vector control cells.
Main Results:
- Transfection dramatically decreased hCG secretion and synthesis in JAR cells.
- Steady-state levels of hCG-alpha and -beta subunit mRNAs significantly decreased.
- Decreased mRNA levels were attributed to increased degradation, not altered transcription.
- Transfected cells maintained normal hCG receptor levels and growth rates.
Conclusions:
- Antisense hCG-alpha cDNA effectively diminishes hCG biosynthesis in choriocarcinoma cells.
- Reduced hCG synthesis does not impair essential cellular functions like receptor expression or growth.
- This study provides insights into hCG gene regulation and potential therapeutic strategies.