Which mechanism does methotrexate utilize to impact cancer cells?

Methotrexate primarily acts by blocking folate metabolism, which is crucial for DNA synthesis and cell division. As a folate antagonist, it inhibits the enzyme dihydrofolate reductase, which is necessary for converting dihydrofolate to tetrahydrofolate. Tetrahydrofolate is vital for the synthesis of purines and pyrimidines, the building blocks of DNA and RNA. By disrupting this process, methotrexate effectively limits the proliferation of rapidly dividing cancer cells, as they depend heavily on the availability of nucleotides for DNA replication.

This mechanism is particularly effective in cancer therapy because many cancer cells have a high rate of growth and division, which makes them more susceptible to agents that interfere with folate metabolism. Thus, methotrexate’s ability to block this metabolic pathway directly impacts the viability and reproduction of cancer cells, leading to their eventual death.