Competitive nested polymerase chain reaction for quantification of human MDR1 gene expression

Area of Science:

• Molecular Biology
• Oncology
• Biochemistry

Background:

• Multidrug resistance (MDR) is a major challenge in chemotherapy, characterized by cellular resistance to various drugs.
• MDR involves biochemical changes like increased glutathione, altered nuclear enzymes (e.g., topoisomerase II), enhanced DNA repair, and P-glycoprotein (gp-170) overexpression.
• P-glycoprotein, encoded by the MDR1 gene, actively pumps drugs out of cells, reducing intracellular drug accumulation and causing resistance.

Purpose of the Study:

• To develop a highly sensitive and specific assay for absolute quantification of MDR1 mRNA.
• To provide a tool for characterizing multidrug resistance gene expression in clinical settings.

Main Methods:

• Development of a competitive polymerase chain reaction (PCR) assay.
• Utilized an in vitro-generated transcript as an internal standard for coamplification with MDR1 cDNA.
• Employed nested MDR1 primers in a second amplification round to enhance assay sensitivity.

Main Results:

• The competitive PCR assay allows for absolute quantification of MDR1 mRNA.
• Nested primers significantly improved the sensitivity of the competitive PCR system.
• The assay demonstrated high sensitivity and specificity for MDR1 expression analysis.

Conclusions:

• The developed competitive PCR assay is a valuable tool for precise MDR1 mRNA quantification.
• This assay has significant clinical relevance for monitoring chemotherapy effectiveness.
• It can aid in the improved design and optimization of chemotherapy regimens.