cancer and its anticancer drugs
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Cancer Presented by Rasika.R.Walunj M.pharm (QAT) Modern College Of Pharmacy (For Ladies), Moshi, Pune. 412105
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Transcript of cancer and its anticancer drugs
Cancer
Presented by Rasika.R.WalunjM.pharm (QAT)
Modern College Of Pharmacy (For Ladies),Moshi, Pune. 412105
What is cancer..???
• Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
• There are more than 100 types of cancer, including breast cancer, skin cancer, lung cancer, colon cancer, prostate cancer, and lymphoma. Symptoms vary depending on the type.
• Cancer treatment may include chemotherapy, radiation, and/or surgery.
How to cancer arise…• Genetic changes that cause cancer can be inherited from
our parents. • They can also arise during a person’s lifetime as a result of
errors that occur as cells divide or because of damage to DNA caused by certain environmental exposures.
• Cancer-causing environmental exposures include substances, such as the chemicals in tobacco smoke, and radiation, such as ultraviolet rays from the sun.
• In general, cancer cells have more genetic changes, such as mutations in DNA, than normal cells. Some of these changes may have nothing to do with the cancer; they may be the result of the cancer, rather than its cause.
"Drivers" of Cancer• The genetic changes that contribute to cancer tend to affect
three main types of genes—proto-oncogenes, tumor suppressor genes, and DNA repair genes. These changes are sometimes called “drivers” of cancer.
• Proto-oncogenes are involved in normal cell growth and division. However, when these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes (or oncogenes), allowing cells to grow and survive when they should not.
• Tumor suppressor genes are also involved in controlling cell growth and division. Cells with certain alterations in tumor suppressor genes may divide in an uncontrolled manner.
Conti..• DNA repair genes are involved in fixing damaged DNA.
Cells with mutations in these genes tend to develop additional mutations in other genes. Together, these mutations may cause the cells to become cancerous.
• As scientists have learned more about the molecular changes that lead to cancer, they have found that certain mutations commonly occur in many types of cancer. Because of this, cancers are sometimes characterized by the types of genetic alterations that are believed to be driving them, not just by where they develop in the body and how the cancer cells look under the microscope.
When Cancer Spreads• A cancer that has spread from the place where it first started to
another place in the body is called metastatic cancer. The process by which cancer cells spread to other parts of the body is called metastasis.
For example, breast cancer that spreads to and forms metastatic tumor in the lung is metastatic breast cancer, not lung cancer. Under a microscope, metastatic cancer cells generally look the same as cells of the original cancer. Moreover, metastatic cancer cells and cells of the original cancer usually have some molecular features in common, such as the presence of specific chromosome changes.
Types of Cancer
• Carcinoma: Cancer that begins in the skin or in tissues that line or cover internal organs
• Sarcoma: Cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
• Leukemia: Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood
Conti..• Lymphoma and myeloma: Cancers that begin in the cells of the
immune system• Central nervous system cancers: Cancers that begin in the tissues of
the brain and spinal cord• Other Types of Tumors• Germ Cell Tumors begins in the cells that give rise to sperm or eggs.
These tumors can occur almost anywhere in the body and can be either benign or malignant
• . Neuroendocrine Tumors Neuroendocrine tumors form from cells that release hormones into the blood in response to a signal from the nervous system.
• These tumors, which may make higher-than-normal amounts of hormones, can cause many different symptoms.
• Neuroendocrine tumors may be benign or malignant.
Anticancer drugs• The anticancer drug either kill cancer cells or modify their
growth. • Discovery of anticancer agents started after 1940’s (when
nitrogen mustard was used) • Most of the agents were discovered in 1950-1970. • Cancer treatment: • Chemotherapy • Radiotherapy • Immunotherapy • Surgery
Classification Anticancer Drugs • Alkylating Agents– Nitrogen mustards: Melphalan,
Cyclophosphamide, Ifosfamide– Nitrosoureas– Alkylsulfonates– Ethyleneimines– Triazene–Methyl Hydrazines– Platinum Coordination complexes: Cisplatin,
Carboplatin, Oxaliplatin
Continue…• Antimetabolites
– Folate Antagonists: Methotrexate – Purine antagonists– Pyrimidine antagonists: 5-Fluorouracil, Cytarabibe
• Natural Products
– Plant Products• Vinca Alkaloids: Vincristine, Vinblastine • Taxanes: Paclitaxel, Docetaxel • Epipodophyllotoxins: Etoposide• Camptothecins: Irinotecan
– Microorganism Products• Antibiotics: Doxorubicin, Bleomycin• Enzymes: L-Asparaginase
Continue…• Miscellaneous– Hydroxyurea – Imatinib Mesylate – Rituximab– Epirubicin– Bortezomib– Zoledronic Acid– Geftinib– Leucovorin– Pamidronate– Gemcitabine
Continue..• Hormones and Antagonists
– Corticosteroids: Prednisone, Dexamethasone – Estrogens: Ethinyloestradiol – Antiestrogens: Tamoxifen – Progesteron derivative: Megestrol Acetate– Androgen: Testosterone propionate – Antiandrogen: Flutamide , Bicalutamide– Aromatase inhibitor: Letrozole , Anastrazole– 5-alpha reductase inhibitor: Finasteride – GnRH Analogue: Leuprolide, Buserelin– Growth Hormone, glucagon and insulin inhibitor: Octreotide
Mechanism action of anticancer drugs• The available anticancer drugs have distinctly different mechanisms
of action which may vary at different drug concentrations and in their effects on different types of normal and neoplastic cells. While not selectively lethal to cancer cells, as such, in many instances
• These drugs produce more extensive injury and death to certain neoplastic cells than to the normal tissues, presumably because of quantitatively altered metabolic processes in the cancer cell.
• In the great majority of cases, also initially responsive cancers recur in a form resistant to the previously effective agent. Despite the many unsolved problems, there is a great deal of information on how anticancer drugs act at the cellular level to inhibit the growth of or to destroy, susceptible cells.
Molecular biology is deoxyribonucleic acid (DNA) to ribonucleic acid (RNA) to protein synthesis. DNA, the genetic material of the cell, acts as the selective template for the production of the specific forms of transfer, ribosomal and messenger ribonucleic acid (RNA). DNA, in directing the formation of specific sequences of messenger RNA, determines which proteins (enzymes) will be synthesized on the RNA templates. The enzymes in turn are responsible for the structure, metabolic activity, proliferative rate, and function of the cell. Interference with the structure of DNA (alkylating agents, procarbazine) or its function(dactinomycin) disorganizes and disrupts the cell. Compounds with this mechanism of action have been useful anticancer drug
DNA Function
Antimetabolite's • Antimetabolites which are incorporated into RNA or act to
inhibit protein synthesis have not proved to be clinically useful in the treatment of cancer.
• Certain antimetabolites inhibit the biosynthesis of the nucleic acids. Interruption in the formation of these essential components of DNA and RNA, which each cell produces in order to function and multiply, results in cell death.
• Antimetabolites with this mechanism of action are useful in some forms of cancer. 6-Mercaptopurifle and 6-thioguanine are prevent purine ring biosynthesis and inter conversion of the purine bases.
Continue..• Methotrexate are inhibits folic acid reductaseto block
the reduction of folic acid totetrahydrofolic acid which transports single carbon fragments for the synthesis of the purine ring and for themethylation of deoxyuridylic acid tothymidylic acid, an essential component of DNA. 5-Fluorouracil is metabolized to its deoxynucleotide form to inhibit the enzyme, thymidylate
• Synthetase, which also is involved in the methylation of deoxyuridylic acid to thymidylic acid; arabinosylcytosine blocks the reduction of cytidylic to deoxycytidylic acid, and by preventing the formation of another essential component of DNA, DNA replication
Vinca alkaloids
• All vinca alkaloids are administered intravenously (IV). They are eventually metabolized by the liver and excreted.
• The vinca alkaloids are cytotoxics – they halt the division of cells and cause cell death. During cell division, vinca alkaloid molecules bind to the building blocks of a protein called tubulin, inhibiting its formation. Tubulin protein normally works in cells to create “spindle fibers,” (also called microtubules).
Continue…
• These microtubules provide cells with both the structure and flexibility they need to divide and replicate. Without microtubules, cells cannot divide.
• The vinca alkaloid’s mechanism in a nutshell: by occupying tubulin’s building block structure, vinca alkaloids prevent cancer cells from successfully dividing cells.
Steroid Hormones
• Un Physiological doses of exogenously administered steroid hormones alter hormonal balance in the patient and modify the growth of some cancers arising from tissues particularly susceptible to hormonal influences.
• The mechanism whereby the steroid hormones stimulate or inhibit cellular growth and function is not clear, but it is believed to be at the level of processes concerned with RNA to protein synthesis.
L-asparaginase
• L-asparaginase acts in a unique manner to hydrolyse asparagine to aspartic acid, and neoplastic cells unable to make this amino acid, die if the supply of L-asparagine in the circulating blood, on which they are dependent, is destroyed by the enzyme.
• Normal cells synthesize L-asparagine for their needs, and thus appear to be unaffected by the L-asparagine deficiency in the body.
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