Enzyme inhibitors are a class of antitumor drugs that block specific enzymes crucial for cancer cell growth and survival. By targeting these enzymes, they disrupt signaling pathways, DNA repair, or metabolism, ultimately inhibiting tumor progression. Key Types of Enzyme Inhibitors in Cancer Therapy
1. Tyrosine Kinase Inhibitors (TKIs) Target: Tyrosine kinases (enzymes involved in cell signaling).
Examples:
– Imatinib (Gleevec) – Chronic Myeloid Leukemia (CML) (inhibits BCR-ABL kinase).
– Erlotinib (Tarceva) – Non-small cell lung cancer (NSCLC) (targets EGFR).
– Sunitinib (Sutent) – Renal cell carcinoma (targets VEGF/PDGF receptors).
2. PARP Inhibitors Target: Poly (ADP-ribose) polymerase (PARP), involved in DNA repair.
Examples:
Olaparib (Lynparza) – BRCA-mutated ovarian / breast cancers.
Rucaparib (Rubraca) – Ovarian/prostate cancers.
3. mTOR Inhibitors Target: mTOR (mammalian target of rapamycin), regulating cell growth.
Examples:
– Everolimus (Afinitor) – Breast/renal cancers.
– Temsirolimus (Torisel) – Advanced renal cell carcinoma.
4. CDK4/6 Inhibitors Target: Cyclin-dependent kinases 4/6 (cell cycle regulators).
Examples:
Palbociclib (Ibrance) – Hormone receptor-positive breast cancer.
Ribociclib (Kisqali) – Similar use in breast cancer.
5. Proteasome Inhibitors Target: Proteasomes (degrade proteins, including tumor suppressors).
Examples:
– Bortezomib (Velcade) – Multiple myeloma
– Carfilzomib (Kyprolis) – Refractory myeloma.
6. IDH Inhibitors Target: Isocitrate dehydrogenase (IDH) mutations in gliomas/AML.
Example:
– Ivosidenib (Tibsovo) – IDH1-mutated acute myeloid leukemia (AML).
How They Differ from Other Antitumor Drugs
- Alkylating agents (e.g., cyclophosphamide) damage DNA directly.
- Antimetabolites (e.g., 5-FU) mimic nucleotides to disrupt DNA synthesis.
- Enzyme inhibitors are more targeted, often with fewer side effects than chemotherapy.