Oncogenes and proto oncogenes , cancer related topic

Seminar Topic

1. SAHYADRI SCIENCE COLLEGE, SHIVAMOGGA-577 203 PG DEPARTMENT OF BIOTECHNOLOGY SEMINAR TOPIC ON – “ ONCOGENES” SUBMITTED BY:- BALAJI G K I MSc I SEM PG Department of Biotechnology Sahyadri Science College Shivamogga-577203 UNDER THE GUIDENCE OF Dr. PRABHAKAR B T Associate Professor PG Department of Biotechnology Sahyadri Science College Shivamogga-577203 KUVEMPU UNIVERSITY

2. CONTENTS INTRODUCTION PROTO-ONCOGENE ONCOGENE MECHANISM OF ONCOGENE ACTIVATION PROTO-ONCOGENE V/ S ONCOGENE LIST OF ONCOGENES MYC ONCOGENE RAS ONCOGENE P53 TUMOR SUPPRESSOR GENE CONCLUSION REFERENCE

3. C a ncer is a complex disease characterized by the abnormal growth and spread of cells. Cells normally grow, divide, and die in a regulated manner, Tumor can be divided in to tow category; B enign (non-cancerous). M alignant (cancerous). Generally mutation leads to the Expression of altered gene products. D ecreased or increased gene expression. INTRODUCTION

4. Two classes of genes affected by genetic and epigenetic alterations in cancer cells are oncogenes and tumor suppressor genes. Oncogenes contribute to tumor development by increased or misdirected activity. Tumor suppressors insufficient or lost function supports tumor development. Oncogenes Tumor Suppressor genes Stimulate Proliferation Inhibit Differentiation Inhibit Apoptosis Inhibit Proliferation Promote Differentiation Stimulate Apoptosis

5. Cancer Proto-oncogenes Tumor Suppressor genes (Active) Oncogenes Tumor Suppressor genes (Inactive)

6. Proto-oncogene

7. ONCOGENES Oncogenes are activated versions of normal cellular genes involved in Regulating cell replication Growth Survival Differentiation Motility Oncogenes become activated by; Genetic mutation Chromosomal translocation Gene amplification An oncogene is a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels.

8. MECHANISM OF ONCOGENE ACTIVATION

9. Proto-oncogene v/s ONCOGENE PROTO-ONCOGENE ONCOGENE A group of genes that cause normal cell to become cancerous when they are mutated. A gene having the potential to cause a normal cell to become cancerous. Unmutated cancer causing genes. Mutated cancer causing genes. It doesn't under go rapid replication. It undergoes rapid replication, and becoming out of control. They are not cancer causing genes. They are cancer causing genes.

10. LIST OF ONCOGENES

11. MYC ONCOGENE The cellular proto-oncogene, c-MYC, encodes the protein c-MYC - promote cell cycle progression, differentiation, cell death and angiogenesis. In normal dividing cells, c-MYC expression is maintained at a relatively constant intermediate level throughout the cell cycle, whereas in its oncogenic form c-MYC might be constitutively expressed at levels ranging from moderate to very high, and is non- responsive to external signals.

12. RAS ONCOGENE The Ras is a protein subfamily of small GTPases that are involved in cellular signal transduction pathways that control actin cytoskeletal integrity, proliferation, differentiation, cell adhesion, apoptosis, and cell migration. Ras communicates signals from outside the cell to the nucleus. Mutations in ras genes can permanently activate it and cause inappropriate transmission inside the cell even in the absence of extracellular signals. These signals result in cell growth and division. Ultimately lead to oncogenesis, decreased apoptosis and cancer.

13. The most important tumor suppressor is p53 (molecular weight 53 kDa ). It is located on band p13 of chromosome 17. Also called "Guardian of the Genome". In 1990, p53 was recognized as the tumor- suppressor gene. Mutation in p53 is the cause of Li-Fraumeni syndrome, which is rare form of inherited cancer. Functions; DNA repairing. Apoptosis. Regulation of cell cycle. Prevent neoplastic transformation either by cell cycle arrest or by triggering apoptosis. P53 - TUMOR SUPPRESSOR GENE

14. CONCLUSION A mutated (changed) form of a type of gene called a proto-oncogene, which is involved in normal cell growth and division. When a proto-oncogene is changed so that too many copies are made or it becomes more active than normal, it is called an oncogene . Several viruses with oncogenic potential stimulate cell proliferation and cause tumors or cancers in animals and humans. They act with different mechanisms depending on different factors.

15. REFERENCE Baron,J.A.,M . Beach, et al. (1999). “Calcium supplements for the prevention of colorectal adenomas.” N Engl J Med 340:101-7 Giovannucci, E., E. B. Rimm , et al. (1994). “Intake of fat, meat, and fiber in relation to risk of colon cancer in men.” Cancer Res 54(9):2390-7. Baron,J.A ., B. F. Cole, et al. (2003). “A randomized trial of aspirin to prevent colorectal adenomas.” N Engl Med 348(10): 891-9

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