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Changes in gene expression during the growth arrest of HepG2 hepatoma cells induced by reducing agents or TGFbeta1
A Cabibbo1, G G Consalez, M Sardella
1Department of Biological and Technological Research (DIBIT), San Raffaele Scientific Institute (HSR), Milano, Italy.
Abstract:
The growth of hepatoma cells can be inhibited by treatment with TGFbeta1 or with exogenous reducing agents. To gain information on the molecular mechanisms underlying growth arrest, we visualized and compared gene expression profiles of proliferating versus non proliferating HepG2 cells by computer-assisted gene fishing, an improved technique of RNA fingerprinting that allows the selective amplification of coding regions within transcripts. While many transcripts are selectively regulated by either treatment, a set of bands appear to be coordinately regulated by 2ME and TGFbeta1, suggesting their possible involvement in the mechanisms of growth arrest. Display tags corresponding to 18 differentially expressed genes were cloned and, in most cases, identified as known genes or, more frequently, as their homospecific/cross-specific homologues. A novel member of the kinesin superfamily was identified amongst the genes induced by both 2ME and TGFbeta1. This gene, KIF3C, is upregulated in several cell lines undergoing growth arrest. Taken together, our findings show that computer-assisted gene fishing is a powerful tool for the identification and cloning of genes involved in the control of cell proliferation and indicate that extracellular reducing agents can regulate cell growth through modulation of gene expression.
Insights
Transforming growth factor beta1 (TGFbeta1) and reducing agents inhibit hepatoma cell growth. Computer-assisted gene fishing identified novel genes, including KIF3C, involved in growth arrest and cell proliferation regulation.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Hepatoma cell proliferation is a target for cancer therapy.
- Transforming growth factor beta1 (TGFbeta1) and reducing agents are known to inhibit hepatoma cell growth.
- Understanding the molecular mechanisms of growth arrest is crucial for developing new therapeutic strategies.
Purpose of the Study:
- To investigate the molecular mechanisms underlying growth arrest in hepatoma cells induced by TGFbeta1 and reducing agents.
- To compare gene expression profiles of proliferating versus non-proliferating HepG2 cells.
- To identify genes coordinately regulated by TGFbeta1 and reducing agents during growth arrest.
Main Methods:
- Computer-assisted gene fishing, an improved RNA fingerprinting technique, was employed to visualize and compare gene expression profiles.
- Selective amplification of coding regions within transcripts.
- Cloning and identification of differentially expressed genes.
Main Results:
- A subset of transcripts were coordinately regulated by both 2-mercaptoethanol (2ME) and TGFbeta1, suggesting their involvement in growth arrest.
- 18 differentially expressed genes were cloned and identified, including known genes, homologues, and a novel kinesin superfamily member, KIF3C.
- KIF3C was found to be upregulated in multiple cell lines undergoing growth arrest.
Conclusions:
- Computer-assisted gene fishing is a powerful tool for identifying and cloning genes that control cell proliferation.
- Extracellular reducing agents can modulate gene expression to regulate cell growth.
- The findings provide insights into the molecular pathways governing hepatoma cell growth arrest.