Related Experiment Videos
Kidney-specific enzyme expression by human kidney cell lines generated through oncogene transfection
1Department of Chemical Engineering, University of Houston, Texas 77004.
Abstract:
The human kidney cell line 293 was generated by transfection of adenovirus DNA into normal human embryonic kidney (HEK) cells (Graham et al., 1977), whereas the human kidney cell lines ST-1i and STt-4i were generated by transfection of HEK cells with plasmids encoding SV40 viral oncogenes (Abcouwer et al., 1989). In this study, we examined kidney-specific enzyme activity levels in 293, ST-1i, and STt-4i cells to determine their ability to exhibit kidney-specific gene expression. Enzymes examined were leucine aminopeptidase (LAP), gamma-glutamyl transpeptidase (gamma-GTP), and the disaccharidases trehalase and maltase. Enzymatic activity levels were compared to three other kidney cell lines (MDCK, OK, and LLC-PK1) as well as to normal human embryonic kidney (HEK) cells and the human hepatoma cell line, Hep G2. Modulation of kidney-specific enzyme activities was assessed in response to several differentiation-inducing agents (adenosine, n-butyric acid, hexamethylene bisacetamide (HMBA), dimethyl sulfoxide (DMSO), N,N'-dimethylformamide (DMF), isobutyl methyl xanthine (IBMX), di butyryl cAMP, and retinoic acid). ST-1i and STt-4i exhibit elevated levels of LAP, gamma-GTP, trehalase, and maltase, consistent with their kidney cell origin, whereas 293 cells exhibit elevated levels of just gamma-GTP and maltase. Maltase and gamma-GTP enzyme activities in ST-1i and STt-4i cells were very responsive to the various inducing agents; 293 cells were less responsive at the inducer concentrations examined. None of the three human cell lines formed domes under any of the experimental conditions. In summary, ST-1i and STt-4i are comparable to normal HEK cells in expression of kidney-specific enzymes and in responsiveness to differentiation-inducing agents, in spite of continued expression of SV40 oncogenes.
Insights
The ST-1i and STt-4i human kidney cell lines demonstrate kidney-specific enzyme expression and differentiation responsiveness, similar to normal HEK cells. The 293 cell line shows limited expression and responsiveness to differentiation agents.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Human kidney cell lines 293, ST-1i, and STt-4i were generated using different methods (adenovirus vs. SV40 oncogenes).
- Assessing kidney-specific gene expression is crucial for understanding kidney cell function and disease modeling.
Purpose of the Study:
- To evaluate kidney-specific enzyme activity in 293, ST-1i, and STt-4i cell lines.
- To compare these cell lines with other kidney cell lines and normal human embryonic kidney (HEK) cells.
- To determine the responsiveness of enzyme activities to differentiation-inducing agents.
Main Methods:
- Enzyme activity assays for leucine aminopeptidase (LAP), gamma-glutamyl transpeptidase (gamma-GTP), trehalase, and maltase.
- Comparison of enzyme levels across multiple kidney and non-kidney cell lines.
- Treatment with various differentiation-inducing agents (e.g., DMSO, retinoic acid) and assessment of enzyme modulation.
Main Results:
- ST-1i and STt-4i cells exhibited elevated levels of LAP, gamma-GTP, trehalase, and maltase, indicative of kidney-specific expression.
- 293 cells showed elevated levels of only gamma-GTP and maltase.
- ST-1i and STt-4i enzyme activities were highly responsive to differentiation agents, while 293 cells were less responsive.
Conclusions:
- ST-1i and STt-4i cell lines are comparable to normal HEK cells in kidney-specific enzyme expression and differentiation response.
- These findings highlight the utility of ST-1i and STt-4i cells for studying kidney-specific gene expression and differentiation.
- The 293 cell line demonstrates a less differentiated phenotype compared to ST-1i and STt-4i cells.