This document discusses several antibiotics that are used as antineoplastic (anti-cancer) agents, including dactinomycin, daunorubicin, doxorubicin, and bleomycin. It explains that these antibiotics are derived from Streptomyces bacteria and work by interfering with DNA transcription and replication in cancer cells. Specifically, it notes that dactinomycin binds to DNA to prevent RNA polymerase activity, while doxorubicin and bleomycin intercalate into DNA and can cause breaks via free radicals or topoisomerase inhibition. The document provides details on the mechanisms and cell cycle specificities of these antibiotic anticancer drugs.

1. Antibiotics in relation with
Antineoplastic agents

2. Antibiotics
• Dactinomycin
• Daunorubicin
• Doxorubicin
• Bleomycin

3. Antibiotics
• Streptomyces-derived antibiotics are used to treat cancer.
• Actinomycin D (also known as dactinomycin), doxorubicin, and
bleomycin are some of the significant medications in this class.

4. • Actinomycin A, was the first Streptomyces antibiotic to be identified
followed by similar antibiotics like actinomycin D.
• DNA transcription is prevented by actinomycin D's binding to double-
stranded DNA and blocking of RNA polymerase activity.
• Actinomycin D, which is administered intravenously but does not
penetrate the blood-brain barrier, is thought to be cell-cycle
nonspecific.

5. • The anthracycline antibiotics, in particular doxorubicin, have
developed into significant anti-cancer drugs.
• These medications attach to DNA by intercalating between base pairs
on neighbouring strands. As a result, the DNA helix unravels,
destroying the DNA template and preventing RNA and DNA
polymerases from working.
• The production of free radicals or the enzyme topoisomerase II are
thought to be the two mechanisms that cause DNA to split.
• Antibiotics that contain anthracyclines interact intracellularly to
produce semiquinone radical intermediates that can produce
hydroxyl and hydrogen peroxide radicals.

6. • These medications, which are thought to be cell-cycle nonspecific
because to the harm caused by radical production, most likely have
their greatest impact during the S phase of the cell cycle.

7. Bleomycin
• In reality, bleomycin is a blend of bleomycin glycopeptides that only
differ in their terminal amine moiety.
• These glycopeptides' capacity to split DNA molecules into chains and
fragment them determines how cytotoxic they are.
• In the G2 stage of the cell cycle, cells gather, which is why bleomycin
is categorised as a G2 and M phase-specific drug. DNA repair enzymes
may also be impacted by bleomycin.
• Bleomycin cannot penetrate the blood-brain barrier whether
administered IV or SC; the majority of it is eliminated through the
kidneys.

8. Chemical Classification

9. Dactinomycin
Actinomycin D (dactinomycin) is a natural chromopeptide composed of a heterocyclic chromophore
and two cyclic pentapeptide lactone rings. The heterocyclic fragment is a phenoxazine derivative,
containing a quinonimine portion, and is responsible for the color of the compound and its
intercalative ability.

10. Daunorubicin

11. Doxorubicin

12. Bleomycin