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Updated: Jul 14, 2026
Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 6, 2015
In vitro chemosensitivity of freshly explanted tumor cells to pemetrexed is correlated with target gene expression
Axel-Rainer Hanauske1, Ulrike Eismann, Olaf Oberschmidt
1Asklepios Klinik, St. Georg, Lohmühlenstr. 5, 20099 Hamburg, Germany. hanauske.ind-synergen@t-online.de
Aim Of The Study:
mRNA expression of genes involved in the mechanism of action of pemetrexed was correlated with in vitro chemosensitivity of freshly explanted human tumor specimens.
Experimental Design:
Chemosensitivity to pemetrexed was studied in soft-agar. Multiplex rtPCR experiments for reduced folate carrier (RFC), folate receptor-alpha (FR-alpha), folylpolyglutamate synthetase (FPGS), thymidylate synthase (TS), dihydrofolate reductase (DHFR), glycinamide ribonucleotide formyl transferase (GARFT), mrp4, and mrp5 were performed in parallel. Correlations, threshold optimization, sensitivity, specificity, and efficiency were analyzed using the appropriate statistical methodologies.
Results:
In 61 samples, low levels of TS, GARFT, DHFR, and mrp4 gene expression significantly correlated with chemosensitivity to pemetrexed. Optimization analyses demonstrated threshold values of 144 copies for TS and six copies for mrp4 relative to 10(4) copies of beta-actin.
Conclusions:
These results form a rational basis for the design of clinical trials to evaluate the expression of these enzymes as predictors for treatment outcome.
Insights
Low expression of thymidylate synthase (TS) and other genes predicts sensitivity to pemetrexed chemotherapy in human tumors. This finding can guide clinical trial design for personalized cancer treatment.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacogenomics
Background:
- Pemetrexed is a chemotherapy agent targeting folate metabolism.
- Predicting patient response to pemetrexed is crucial for effective cancer treatment.
Purpose of the Study:
- To correlate mRNA expression of pemetrexed-related genes with in vitro chemosensitivity.
- To identify potential biomarkers for pemetrexed efficacy in human tumors.
Main Methods:
- Chemosensitivity assays were performed using soft-agar.
- Multiplex RT-PCR was used to quantify gene expression of RFC, FR-alpha, FPGS, TS, DHFR, GARFT, MRP4, and MRP5.
- Statistical analyses were conducted to determine correlations and optimize thresholds.
Main Results:
- Low expression of thymidylate synthase (TS), glycinamide ribonucleotide formyl transferase (GARFT), dihydrofolate reductase (DHFR), and mrp4 correlated significantly with pemetrexed chemosensitivity.
- Optimal threshold values were determined for TS (144 copies) and mrp4 (6 copies) relative to beta-actin.
Conclusions:
- Gene expression levels of TS, GARFT, DHFR, and mrp4 can serve as predictors of pemetrexed treatment response.
- These findings provide a basis for designing clinical trials to utilize these markers for personalized cancer therapy.
