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Expression of hormone-sensitive lipase in the human colon adenocarcinoma cell line HT29
A Remaury1, H Laurell, J Grober
1INSERM Unité 317, Institut Louis Bugnard, Centre Hospitalier Universitaire de Rangueil, Toulouse, France.
Abstract:
Hormone-sensitive lipase expression was studied in the human colon adenocarcinoma cell line, HT29. Diacylglycerol lipase and cholesterol esterase [corrected] activities in HT29 cells were inhibited by known inhibitors of hormone-sensitive lipase (diethyl-p-nitrophenyl phosphate, NaF and HgCl2) to the same extent as in human adipocytes. A polyclonal antiserum directed against rat hormone-sensitive lipase inhibited 89% of HT29 cell lipase activity. HT29 hormone-sensitive lipase was the same size as the adipocyte enzyme as was its mRNA. Complete homology between mRNA sequences in HT29 and adipocyte was demonstrated using ribonuclease protection assay. These data are consistent with the expression of a protein closely related, if not identical, to the enzyme expressed in human adipose tissue. HT29 is the first human cell line where hormone-sensitive lipase expression has been shown.
Insights
Researchers found that the HT29 colon cancer cell line expresses hormone-sensitive lipase, an enzyme typically found in fat cells. This discovery marks the first human cell line shown to express this important lipase.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Hormone-sensitive lipase (HSL) is a key enzyme involved in lipid metabolism, primarily studied in adipose tissue.
- Understanding HSL expression in non-adipose tissues, particularly in disease contexts like cancer, is crucial for metabolic research.
Purpose of the Study:
- To investigate the presence and characteristics of hormone-sensitive lipase (HSL) expression in the human colon adenocarcinoma cell line, HT29.
- To compare the properties of HSL in HT29 cells with that found in human adipocytes.
Main Methods:
- Enzyme activity assays using known HSL inhibitors (diethyl-p-nitrophenyl phosphate, NaF, HgCl2).
- Immunoinhibition assays with a polyclonal antiserum against rat HSL.
- Western blotting to determine enzyme size.
- Ribonuclease protection assays to analyze mRNA sequence homology.
Main Results:
- HT29 cells exhibited diacylglycerol lipase and cholesterol esterase activities inhibited by HSL inhibitors, similar to human adipocytes.
- An anti-HSL antiserum inhibited 89% of lipase activity in HT29 cells.
- HSL in HT29 cells was identical in size to the adipocyte enzyme, and its mRNA showed complete sequence homology with adipocyte mRNA.
Conclusions:
- The HT29 colon adenocarcinoma cell line expresses a protein closely related, if not identical, to human adipose tissue hormone-sensitive lipase.
- This study demonstrates hormone-sensitive lipase expression in HT29 cells, representing the first human cell line identified with this characteristic.