Pralatrexate
Treatment of relapsed or refractory peripheral T-cell lymphoma.
The selectivity of pralatrexate for cancer cells is based upon the observation that cancer cells generally have an overexpression of reduced folate carrier protein-1 (RTC-1) compared to normal somatic cells. This carrier protein allows the entrance of pralatrexate into the cell. Upon entering the cell, folypolyglutamate synthase FPGS catalyzes the polyglutamination of pralatrexate so that it is retained inside the cell. Once inside, pralatrexate competitively inhibits dihydrofolate reductase (DHFR) and thymidylate synthase. Subsequent depletion of thymidine monophosphate (TMP) occurs so that the cancer cell is unable to synthesize DNA and RNA. As a result, the cancer cell cannot proliferate and is forced to undergo apoptosis. Pralatrexate is more effective against cells that are actively dividing.