What is the mechanism of action of platinum compounds?

Platinum compounds, like cisplatin, work primarily by forming covalent bonds with DNA, leading to the cross-linking of DNA strands. Specifically, they typically create adducts between guanine bases, resulting in the formation of G-G (guanine-guanine) or G-A (guanine-adenine) cross-links. This cross-linking prevents DNA from unwinding, which is essential for replication and transcription, thus inhibiting cancer cell division and leading to cell death.

The process interferes with the normal function of DNA, which is critical in rapidly dividing cancer cells, causing cellular damage that can result in apoptosis. The effectiveness of platinum compounds in chemotherapy is largely due to this DNA cross-linking mechanism, making option B the correct choice.