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Multidrug-resistant gene expression in small-cell lung cancer
Abstract:
The development of drug resistance can contribute to treatment failure in small-cell lung cancer (SCLC). In this report, we investigate p-glycoprotein-mediated multidrug resistance (MDR) in these patients. Tumor tissue was obtained prior to treatment and at relapse if possible, short-term culture was carried out, and these tumor cells were analyzed for MDR gene expression by slot blot and reverse transcriptase polymerase chain reaction (RT-PCR) and northern blot analysis. Three cell lines were also established from short-term cultures. Twenty-four patients with MDR(-) and seven with MDR +(++) were available for survival analysis. Median survival for MDR (-) patients was 10 months, whereas for MDR +(++) patients it was 2 months. This was statistically significance (p < 0.0007). The presence of MDR1 gene expression also correlated with the lack of response to chemotherapy (p < 0.001). Increased MDR1 gene expression is usually present in patients with more tumor burden at initial diagnosis. Furthermore, loss of MDR1 gene expression can occur in intrinsically MDR(+) SCLC cells after multiple passages in drug-free media. We concluded that increased MDR1 gene expression is present in a small number of SCLC both before and after chemotherapy and usually signifies poor survival and no response to chemotherapy.
Insights
Multidrug resistance (MDR) in small-cell lung cancer (SCLC) is linked to treatment failure. Increased MDR1 gene expression in SCLC patients correlates with poor survival and lack of chemotherapy response.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- Drug resistance is a major cause of treatment failure in small-cell lung cancer (SCLC).
- P-glycoprotein-mediated multidrug resistance (MDR) is a key mechanism contributing to treatment failure in SCLC.
- Understanding MDR in SCLC is crucial for developing effective therapeutic strategies.
Purpose of the Study:
- To investigate the role of p-glycoprotein-mediated multidrug resistance (MDR) in small-cell lung cancer (SCLC).
- To analyze MDR gene expression in SCLC tumors before and after chemotherapy.
- To correlate MDR gene expression with patient survival and response to treatment.
Main Methods:
- Tumor tissue was collected from SCLC patients before treatment and at relapse.
- Short-term cultures of tumor cells were established for analysis.
- MDR gene expression was assessed using slot blot, reverse transcriptase polymerase chain reaction (RT-PCR), and northern blot analysis.
- Survival analysis was performed on patients categorized as MDR-negative (MDR(-)) and MDR-positive (MDR(+)).
Main Results:
- Median survival for MDR(-) patients was 10 months, compared to 2 months for MDR(+) patients (p < 0.0007).
- The presence of MDR1 gene expression significantly correlated with a lack of response to chemotherapy (p < 0.001).
- Increased MDR1 gene expression was often observed in patients with a higher tumor burden at initial diagnosis.
Conclusions:
- Increased MDR1 gene expression is present in a subset of SCLC patients, both before and after chemotherapy.
- Elevated MDR1 gene expression is a significant indicator of poor survival and unresponsiveness to chemotherapy in SCLC.
- Further research into overcoming MDR mechanisms in SCLC is warranted.