Deadly Beauty: Drugs under the Microscope These gorgeous images are of drugs that kill our cells as surely as they may heal us. Widely used in cancer chemotherapy and other disorders, they make us wonder at their beauty and question how they are used.
• Mitomycin: DNA crosslinker antibiotic from Streptomyces. Used in glaucoma and lasik surgery, bladder, oesophageal and other cancers. Works by blocking DNA replication in dividing cells.
• Azacititine: DNA methylase blocker used to treat myelodysplastic syndrome, and in clinical trials for relapsed acute myeloid leukemia (AML). Masquerades as a “C” nucleoside but cannot get modified so it blocks DNA methyltransferase and thus activate tumor suppressor genes silenced by hypermethylation.
• Mitoxantrone: DNA topoisomerase inhibitor, used to treat metastatic breast cancer, AML, non-Hodgkin’s lymphoma,and prostate cancer. During replication, DNA becomes “overwound” ahead of the replication fork. The topological tension is relieved by topoisomerases.The enzyme binds to “tense” DNA and cleaves the phosphate backbone; the DNA unwinds and, then topoisomerase reseals the break.
• Fluoxetine (Prozac): Antidepressant blockbuster drug, works by inhibiting serotonin reuptake. Also used to treat obsessive compulsive disorder and eating disorders.
• Trastuzumab (Herceptin): A monoclonal antibody that blocks the HER2/neu receptor and is used in the treatment of certain breast cancers. The HER2 gene is amplified in some cancers where it causes excessive cell growth. The treatment is very expensive ($100,000 a year) and cancers tend to become resistant.
ScienceSunday , #sciencesunday