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Isolation of a polyamine transport deficient cell line from the human non-small cell lung carcinoma line NCI H157
Abstract:
In an effort to study the mechanism underlying the observed phenotype-specific response of human lung cancer cell lines to a polyamine analogue, N1,N12-bis(ethyl)spermine(BESpm), we have isolated a BESpm resistant cell line from the BESpm-sensitive large cell lung carcinoma line NCI H157. The mutant line exhibits identical growth rates in the presence or absence of the analogue. However, the overall growth of mutant cells reaches stationary phase earlier than that of the parental cells. In contrast to the parental cells, where a superinduction of spermidine/spermine N1-acetyltransferase (SSAT) is associated with BESpm toxicity, treatment of this resistant line with BESpm did not induce SSAT mRNA or enzyme activity. BESpm treatment was not effective in depleting the intracellular polyamine pools and very low intracellular BESpm levels were detected. This BESpm resistance is not mediated by multidrug resistance (MDR) protein, since these cells maintain their sensitivity to the antineoplastic agent adriamycin. Treatment of these cells with methylglyoxal bis(guanylhydrazone) (MGBG), an AdoMetDC inhibitor which enters cell using polyamine transport system, shows no inhibition of cell growth. Our data suggest that these mutant cells are deficient in polyamine transport. Consistent with this hypothesis, exogenous polyamines did not prevent difluoromethylornithine (DFMO) induced growth inhibition in the mutant cells.
Insights
Researchers developed a resistant lung cancer cell line to study polyamine analogue N1,N12-bis(ethyl)spermine (BESpm) response. The resistant cells showed impaired polyamine transport, suggesting a new therapeutic target for lung cancer.
Area of Science:
- Oncology
- Molecular Pharmacology
- Cell Biology
Background:
- Lung cancer cell lines exhibit varied responses to polyamine analogues like N1,N12-bis(ethyl)spermine (BESpm).
- Understanding resistance mechanisms is crucial for developing effective cancer therapies.
Purpose of the Study:
- To investigate the mechanism of resistance to the polyamine analogue BESpm in a human lung cancer cell line.
- To characterize a newly isolated BESpm-resistant cell line derived from NCI H157 cells.
Main Methods:
- Isolation and characterization of a BESpm-resistant cell line from NCI H157 large cell lung carcinoma cells.
- Assessing growth rates, spermidine/spermine N1-acetyltransferase (SSAT) induction, intracellular polyamine levels, and drug sensitivity (adriamycin, methylglyoxal bis(guanylhydrazone)).
- Evaluating the response to difluoromethylornithine (DFMO) in the presence of exogenous polyamines.
Main Results:
- The resistant cell line showed no SSAT induction or significant intracellular BESpm accumulation upon treatment.
- Resistance was not mediated by multidrug resistance (MDR) proteins, as adriamycin sensitivity was retained.
- The mutant cells exhibited impaired polyamine transport, evidenced by lack of growth inhibition by MGBG and unaltered DFMO response with exogenous polyamines.
Conclusions:
- The developed BESpm-resistant cell line is deficient in polyamine transport.
- Polyamine transport is a key factor in the cellular response to BESpm in lung cancer.
- Targeting polyamine transport may offer a novel therapeutic strategy for lung cancer treatment.