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Molecular and genetic characterization of human cell lines resistant to L-asparaginase and albizziin
I L Andrulis1, R Argonza, A E Cairney
1Mount Sinai Hospital Research Institute, Toronto, Ontario, Canada.
Abstract:
Human cell lines resistant to L-asparaginase or albizziin were isolated by multistep selection of HT1080 fibrosarcoma and MIA PaCa-2 pancreatic carcinoma cells. Mutants were cross-resistant to both drugs, but more resistant to the drug used for selection. The drug-resistant cell lines expressed elevated levels of asparagine synthetase activity and protein, up to 17-fold over that of the parental cells. Enzyme overproduction was due to gene amplification in the albizziin-resistant cells, whereas increased expression without amplification was observed in L-asparaginase-resistant cells.
Insights
Drug resistance in cancer cells was studied using L-asparaginase and albizziin. Resistant cell lines showed increased asparagine synthetase, with gene amplification in albizziin-resistant cells but not L-asparaginase-resistant cells.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- L-asparaginase and albizziin are drugs used in cancer therapy.
- Resistance to these drugs can limit treatment efficacy.
- Understanding resistance mechanisms is crucial for improving cancer treatments.
Purpose of the Study:
- To investigate the mechanisms of resistance to L-asparaginase and albizziin in human cancer cell lines.
- To characterize the changes in asparagine synthetase in drug-resistant cells.
Main Methods:
- Multistep drug selection was used to generate resistant cell lines from HT1080 fibrosarcoma and MIA PaCa-2 pancreatic carcinoma.
- Asparagine synthetase activity and protein levels were measured.
- Gene amplification was assessed in resistant cell lines.
Main Results:
- Resistant cell lines exhibited cross-resistance to both L-asparaginase and albizziin.
- Elevated asparagine synthetase activity and protein levels (up to 17-fold) were observed in resistant cells.
- Albizziin-resistant cells showed gene amplification of asparagine synthetase, while L-asparaginase-resistant cells showed increased expression without amplification.
Conclusions:
- Increased asparagine synthetase is a key mechanism of resistance to L-asparaginase and albizziin.
- Gene amplification is responsible for enzyme overproduction in albizziin resistance.
- Increased gene expression without amplification underlies L-asparaginase resistance.