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A novel protein-tyrosine kinase, tec, is preferentially expressed in liver
H Mano1, F Ishikawa, J Nishida
1Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Abstract:
To identify protein-tyrosine kinases which play an important role in the process of hepatocarcinogenesis, we have screened a murine liver cDNA library with v-fps kinase domain as a probe. Using low stringency screening, we could isolate cDNAs of a putative protein-tyrosine kinase, tec (tyrosine kinase expressed in hepatocellular carcinoma). Nucleotide sequences of the cDNAs show that the C-terminal domain of its predicted protein has significant homology with that of the members of the src family. The tec gene is expressed mainly in liver and faintly in heart, kidney and ovary. Northern analysis further shows that in 2 out of 4 cell lines of human hepatocellular carcinoma (HCC) the tec gene is highly expressed compared to normal human liver. This is the first report showing a protein-tyrosine kinase which may be specifically involved in the cell growth of hepatocytes or in the step of hepatocarcinogenesis.
Insights
Researchers identified a novel protein-tyrosine kinase, tec (tyrosine kinase expressed in hepatocellular carcinoma), potentially crucial for liver cancer development. This kinase shows high expression in hepatocellular carcinoma cells, suggesting a role in hepatocarcinogenesis.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- Hepatocellular carcinoma (HCC) is a major global health concern.
- Identifying key molecular players in hepatocarcinogenesis is crucial for targeted therapies.
Purpose of the Study:
- To screen for novel protein-tyrosine kinases involved in liver cancer development.
- To characterize a newly identified kinase, tec, and its role in hepatocellular carcinoma.
Main Methods:
- Screening of a murine liver cDNA library using a v-fps kinase domain probe.
- Low stringency screening to isolate potential kinase cDNAs.
- Nucleotide sequencing and Northern blot analysis to assess gene expression.
Main Results:
- Isolation of cDNAs for a putative protein-tyrosine kinase, tec.
- The tec gene shows significant homology to the src family of kinases.
- Tec gene is primarily expressed in the liver and highly upregulated in human HCC cell lines compared to normal liver tissue.
Conclusions:
- Tec is a novel protein-tyrosine kinase potentially involved in hepatocarcinogenesis.
- Tec may play a specific role in hepatocyte cell growth or liver cancer progression.
- This finding provides a new molecular target for hepatocellular carcinoma research.