2.8 Anti tumour antibiotics

Question 1

What are the 5 different classes of chemotherapy?

Answer 1

• Alkylating agents
• Antimetabolites
• Topoisomerase inhbitors
• Mitotic inhibitors
• Anti tumour antibiotics

Question 2

Name 3 anti tumour antibiotics

Answer 2

• Bleomycin
• Mitomycin
• Dactinomycin

Question 3

Broadly what is the mode of action of anti-tumour antibiotics?

Answer 3

They bind to DNA, inserting themselves between base pairs of DNA, to cause single and double stranded DNA breaks.

This leads to DNA damage and a reduction in mitosis of cancer cells.

Question 4

What is the mode of action of bleomycin?

Answer 4

• Bleomycin Inserts itself between base pairs of DNA, in cancer cells causing single and double stranded DNA breaks.
• Bleomycin also geerates reactive oxygen species and can inhibit DNA synthesis and repair
• These effects collectively result in apoptosis of cancer cells.

Question 5

What is one of th problems with Bleomycin?

Answer 5

Strongly associated with pulmonary toxicity as the dose accumulates?

Question 6

Which type of cancer is bleomycin often used to treat?

Answer 6

• Lymphoma
• Germ cell tumours

Question 7

What is the mode of action of mitomycin?

Answer 7

• Mitomycin works by forming crosslinks between the strands of DNA, specifically between guanine bases.
• These crosslinks interfere with the normal structure and function of DNA, preventing DNA replication and transcription within cancer cells.
• Bleomycin also generates reactive oxygen species and can inhibits DNA synthesis and repair
• These effects collectively result in apoptosis of cancer cells

Question 8

Which type of tumours might mitomycin be used to treat?

Answer 8

It’s used in the treatment of a limited number of solid tumours including breast, anal and bladder cancers.

Question 9

What is the mode of action of Dactinomycin?

Answer 9

Dactinomycin inserts itself between base pairs of DNA paticularly the guaninine-cytosine rich regions.

Datamycin then prevents the enzyme RNA polymerase from effectively transcribing the DNA into RNA.

This inhibition of RNA synthesis disrupts the production of messenger RNA (mRNA), which carries the genetic information from DNA to the ribosomes for protein synthesis.

Without the proper mRNA transcripts, protein synthesis is inhibited in the cell.

This disruption of protein synthesis affects various cellular processes and ultimately leads to the death of the cancer cells.

Question 10

Which cancers might Dactinomycin be used to treat?

Answer 10

Paediatric tumours including:

• Ewing sarcoma,
• Rhabdomyosarcoma.
• Wilms tumour.

Question 11

What is the other name for Dactinomycin

Answer 11

Actinomycin-D