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Study of multidrug resistance (mdr1) gene in non-small-cell lung cancer
Abstract:
Non-small-cell lung cancer (NSCLC) is one of the tumors that shows intrinsic drug resistance to various chemotherapeutic agents. We investigated a possible role of the multidrug resistance (mdr1) gene amplification using a DNA slot blot analysis in 23 untreated non-small-cell lung cancer tissues and 14 corresponding adjacent normal lung tissue samples. In all instances, whether tumors or adjacent normal tissue samples, DNA amplification was not detected except in 1 adenocarcinoma and 2 squamous cell carcinomas that had a low level of amplification of mdr1 gene. In addition, 6 untreated tumors and 7 normal tissue samples were examined for mdr1 RNA expression using RNA slot blot analysis. Only low levels of mdr1 expression were observed in all cases. We conclude that mechanisms other than mdr1 amplification or expression account for the intrisic drug resistance of non-small-cell lung cancers.
Insights
Multidrug resistance (mdr1) gene amplification and expression are not primary causes of intrinsic drug resistance in non-small-cell lung cancer (NSCLC). Further research is needed to identify other resistance mechanisms in NSCLC tumors.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Non-small-cell lung cancer (NSCLC) frequently exhibits intrinsic resistance to chemotherapy.
- The multidrug resistance (mdr1) gene is a potential mediator of this chemoresistance.
Purpose of the Study:
- To investigate the role of mdr1 gene amplification and expression in intrinsic drug resistance in NSCLC.
- To determine if mdr1 alterations correlate with treatment outcomes in NSCLC patients.
Main Methods:
- DNA slot blot analysis was performed on 23 untreated NSCLC tissues and 14 adjacent normal lung tissues to detect mdr1 gene amplification.
- RNA slot blot analysis was used to examine mdr1 gene expression in 6 untreated tumors and 7 normal tissue samples.
Main Results:
- MDR1 gene amplification was detected at low levels in only 3 NSCLC samples (1 adenocarcinoma, 2 squamous cell carcinomas).
- Low levels of mdr1 gene expression were observed in all examined tumor and normal tissue samples.
- No significant correlation was found between mdr1 amplification/expression and intrinsic drug resistance in NSCLC.
Conclusions:
- MDR1 gene amplification and expression do not appear to be major contributors to intrinsic drug resistance in NSCLC.
- Alternative molecular mechanisms likely underlie the observed chemoresistance in NSCLC.
- Further studies are warranted to elucidate the precise mechanisms of drug resistance in NSCLC.