Chemotherapy Biotherapy Certification ONS Practice Testq

What is the primary mechanism of action for nitrosoureas in cancer treatment?

1. Inhibiting protein synthesis

2. Disrupting DNA transcription and inhibiting DNA and RNA synthesis

3. Altering the cell's membrane permeability

4. Blocking enzymes necessary for DNA synthesis

The correct answer is: Disrupting DNA transcription and inhibiting DNA and RNA synthesis

Nitrosoureas are a class of chemotherapy agents that primarily exert their effects by disrupting DNA transcription and inhibiting both DNA and RNA synthesis. This mechanism is crucial for their efficacy in treating various types of cancer. When nitrosoureas enter the cell, they undergo metabolic conversion, which leads to the formation of reactive intermediates. These intermediates are capable of alkylating DNA, leading to cross-linking of DNA strands and preventing proper replication and transcription. This interference with the genetic material is particularly important for rapidly dividing cancer cells, which rely heavily on DNA synthesis for proliferation. By inhibiting the synthesis of DNA and RNA, nitrosoureas effectively target and kill these malignant cells, making them valuable in oncology treatments. The other choices focus on different mechanisms of action not specific to nitrosoureas. For example, inhibiting protein synthesis typically involves different classes of drugs, while altering membrane permeability is not a primary action of nitrosoureas. Blocking enzymes necessary for DNA synthesis is related but does not encompass the broader impact that these agents have on both DNA and RNA production. This understanding highlights the unique role of nitrosoureas in cancer treatment and underscores their mechanism of action as central to their therapeutic effects.