Anticancer Antibiotics

advertisement

Anticancer Agents

By:

Cristina Sanders

What is cancer?

Cancer is a group of diseases that are characterized by the loss of control of the growth, division, and spread of a group of cells leading to a primary tumor that invades and destroys adjacent tissues

Become rogue cells and frequently lose their differentiation

 Two types: benign and malignant

 Spread through metastasis

QuickTime™ and a

decompressor are needed to see this picture.

How cancer develops

Can be inherited or develop by being exposed to certain environmental factors

(cigarette smoke, alcohol, certain diets)

Tumorigenesis - accumulation of mutations in oncogenes that deregulates the cell cycle

Cancer Link

QuickTime™ and a

decompressor are needed to see this picture.

Cell cycle

QuickTime™ and a

decompressor are needed to see this picture.

History of Cancer Treatment

Long history of treating cancer, but did not successfully begin until the invention of the microscope

Early 20th - surgery and radiation

World Wars began chemical warfare, and thus began chemotherapy - nitrogen mustards

Currently, targeted cancer therapy

Common Treatments

Surgery

Direct removal of tumor

Radiotherapy

Using ionizing radiation to control malignant cells

Chemotherapy

Using chemicals to kill actively dividing cells

Chemotherapy

Injection - Intrathecal,

Intramuscular, Intravenous, Intraarterial

Orally

Topically QuickTime™ and a

decompressor are needed to see this picture.

Drug targets

Enzymes - Antimetabolites

Hormones - Androgens, Oestrogens, Progestins,

LHRH agonists, Antioestrogens, Antiandrogens

Nucleic Acids - Intercalating agents, alkylating agents, chain cutters

Structural proteins

Signaling pathways

Intercalating Agents

The reversible inclusion of a molecule between two other groups, most commonly seen in DNA

Inhibits DNA replication in rapidly growing cells

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

Anthracyclines

First anthracycline antibiotics were isolated from Streptomyces peucetius in 1958

Interact with DNA by intercalcation and inhibit topsoimerase

Some of the most effective cancer drugs available

Very wide spectrum

Common Anthracyclines

Daunorubicin (Cerubidine)

Doxorubicin (Adriamycin, Rubex)

Epirubicin (Ellence, Pharmorubicin)

Idarubicin (Idamycin)

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

Anthracycline structures

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

http://images.google.com/imgres?imgurl=http://www.ncbi.nlm.nih.gov/bookshelf/picrender.fcgi%3Fbook%3Dcmed%26part%3DA11644%26blobname%3Dch49f5.jpg&imgrefurl=http://www.ncbi.nlm.ni

h.gov/bookshelf/br.fcgi%3Fbook%3Dcmed%26part%3DA11644&usg=__1ixIg12np9lq0vQwN14mBnjs5oU=&h=744&w=412&sz=53&hl=en&start=2&um=1&itbs=1&tbnid=TYigCqbnaRkjfM:&tbnh=141

DOX vs. DNR

Daunomycin (DNR) for acute lymphocytic and myeloid leukenmia

Doxorubicin (DOX) for chemotherapy for solid tumors including breast cancer, soft tissue sarcomes, and aggressive lymphomas

QuickTime™ and a

decompressor are needed to see this picture.

Mechanisms of action

Disrupt DNA

 Intercalate into the base pairs in DNA minor grooves

Inhibits topoiosomerase II enzyme, preventing the relaxing of supercoiled

DNA, thus blocking DNA transcription and replication

Cause free radical damage of ribose in the DNA

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

Intercalating Mechanism

 The planar aromatic chromophore portion of the molecule intercalates between two base pairs of the DNA, while the sixmembered daunosamine sugar sits in the minor groove and interacts with flanking base pairs immediately adjacent to the intercalation site

Prevents Topoisomerase II and stabilizes the complex, preventing the

DNA helix from resealing

QuickTime™ and a

decompressor are needed to see this picture.

QuickTime™ and a

decompressor are needed to see this picture.

Free Radical Formation

Adds to the cardiotoxicity of anthracyclines

QuickTime™ and a

decompressor are needed to see this picture.

Negative Effects

Causes cardiotoxicity

Interference with ryanodine receptors of the sarcoplasmic reticulum in the heart muscle cells

Free-radical formation in the heart

Leads to forms of congestive heart failure, often years after treatment

Counteract with dexrazoxane

QuickTime™ and a

decompressor are needed to see this picture.

Bleomycins (BLM)

Natural glycopeptidic antibiotics produced by Streptomyces verticillus

Efficacy against tumors

Mainly used in therapy in a combination with radiotherapy or chemotherapy

Commonly administered as Blenoxane, a drug that includes both bleomycin A

B

2

.

2 and

History of Bleomycins

First discovered in 1966 by Hamao

Umerzawa from Japan when screening cultures of S. verticullus

Launched in Japan by Nippon kayaku in 1969

Initially marketed by Bristol-Myers

Squibb under brand name QuickTime™ and a

decompressor are needed to see this picture.

Blenoxance

Structure

Mechanism

Induction of DNA strand breaks

Medicate DNA strand scission of single and double strand breaks dependent on metal ions and oxygen

Bleomycin Action 2:10, 3:13

Side effects

Pulmonary fibrosis and impaired lung function

Age and dose related

Capillary changes, atypical epithelial cells

Resistance to Anticancer Agents

Resistance mechanisms can operate to

Prevent agents from entering cells, as in loss of plasma membrane carriers for nucleoside analogs

Enhance their extrusion, as exemplified by energy-dependent pumps such as ABC transporters

Reading Assignment

Patrick, Graham L. An Introduction to Medicinal

Chemistry . 3 rd ed. Oxford: Oxford University

Print, 2005. p.489-504

Hurley, Laurence H. DNA and its associated processes as targets for cancer therapy. Nature

Reviews Cancer (2002), 2(3), 188-200.

Homework Questions

What are some cellular defects that are associated with cancer?

Describe the mechanism of DNA intercalation and how it is used to treat cancer.

Draw the two main structures of Anthracyclines and label the areas involved in the mechanism of action.

How does doxorubicin interfere with topoisomerase II?

References

Avenda, Carmen, and J. Carlos Menedez. Medicinal Chemistry of Anticancer Drugs .

Amsterdam: Elsevier, 2008 http://www.scribd.com/doc/11639473/Medicinal-Chemistry-of-

Anticancer-Drugs

Chang, Jingyang, and JoAnne Stubbe. "Bleomycins: New Methods Will Allow

Reinvestigation of Old Issues." Current Opinion in Chemical Biology 8.2 (2004): 175-81.

Claussen, Craig A., and Eric C. Long "Nucleic Acid Recognition by Metal Complexes of

Bleomycin." Chemical Reviews 99 (1999): 2797-816.

Hortobyi, G. N. "Anthracyclines in the Treatment of Cancer: An Overview." Drugs 54 (1997):

1-7.

Hurley, Laurence H. "DNA And Its Associated Processes as Targets For Cancer Therapy."

Nature 2 (2002): 188-200. EBSCOhost . Web. 28 Mar. 2010.

<http://web.ebscohost.com/ehost/pdf?vid=2&hid=107&sid=c129efcf-31ba-47d2-960ddfb68ea0e0bd%40sessionmgr104>.

Papac, Rose J. "Origins of Cancer Therapy." Yale Journal of Biology and Medicine 74 (2002):

391-98. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2588755/?page=1

Patrick, Graham L. An Introduction to Medicinal Chemistry . 3 rd ed. Oxford: Oxford University

Print, 2005.

Pratt, William B. The Anticancer Drugs . New York: Oxford UP, 1994.

 http://www.cancerquest.org/index.cfm?page=2225

 http://knol.google.com/k/history-of-cancertreatment#History_of_Cancer_Treatmenthttp://www.drugs.com/sfx/bleomycin-sideeffects.html

Download