How do alkylating agents work in chemotherapy?

Alkylating agents work in chemotherapy by directly modifying the DNA structure of cancer cells. These agents introduce alkyl groups into the DNA molecule, leading to cross-linking of DNA strands. This cross-linking inhibits DNA replication and transcription, ultimately preventing the cancer cell from dividing and proliferating effectively. By damaging the DNA, alkylating agents increase the likelihood of apoptosis, or programmed cell death, in cancer cells.

In the context of cancer treatment, the direct alteration of the DNA structure is a critical mechanism as it targets the fundamental aspects of cancer cell growth and survival. This mode of action is essential in the fight against rapidly dividing cancer cells, making alkylating agents an important component of certain chemotherapy regimens.

The other options, while they describe different mechanisms of action relevant to other types of cancer treatments, do not apply to alkylating agents specifically. For instance, obstructing blood supply to tumors is characteristic of anti-angiogenic therapies, enhancing immune response pertains to immunotherapy, and promoting apoptosis can involve various agents but is not the primary action of alkylating agents.