Prof. Dr. Aguinaldo Roberto Pinto Laboratório de Imunologia Aplicada MIP/CCB/UFSC

1. Vírus Oncogênicos e Câncer Prof. Dr. Aguinaldo Roberto Pinto Laboratório de Imunologia Aplicada MIP/CCB/UFSC

2. Câncer • Hipócrates, por volta do ano 400 a.C • Câncer: As veias que irradiam a partir de alguns tumores de mama assemelham-se com as pernas de um caranguejo. • Ele deu à moléstia o nome de karkinoma (carcinoma), palavra grega que também significa caranguejo, e a mesma associação chegou ao latim.

3. Células cancerosas ou tumorigênicas variantes de células normais que perderam a habilidade de controlar seu crescimento com as seguintes alterações: • Imortalização • Transformação • Metástase

4. Fibroblastos normais (monocamada) Fibroblastos transformados (arredondados e em colônias)

5. Célula Normal Câncer • Estima-se que 6-7 eventos devem ocorrer (em ~20-40 anos) para indução do câncer (alterações genéticas e epigenéticas) • em certos casos a propensão ao câncer é hereditária

6. Célula Normal Agentes Carcinogênicos: iniciam ou promovem a formação do tumor Célula Tumoral (transformada)

7. Fatores carcinogênicos • Fumo • pulmão, esôfago, bexiga e pâncreas • Hábitos alimentares (gorduras saturadas e fibras) • cólon • Obesidade • endométrio, cólon, rim, vesícula • Álcool • trato digestivo e respiratório • Vírus

8. Vírus e Câncer • 1908, Wilhelm Ellerman & Olaf Bang • Leucemia de galinha podia ser transmitida por inoculação de filtrado de células tumorais • 1911, F. Peyton Rous • Sarcoma de galinha – Nobel em 1966

10. Vírus e Câncer • 1908, Wilhelm Ellerman & Olaf Bang • Leucemia de galinha podia ser transmitida por inoculação de filtrado de células tumorais • 1911, F. Peyton Rous • Sarcoma de galinha – Nobel em 1966 • 1936, Bittner • Carcinoma mamário de camundongos causado por vírus transmitido pela mãe • Gross & Friend • Vírus relacionado à leucemia de camundongos

11. Vírus oncogênicos - DNA

12. Vírus oncogênicos - RNA

13. Tumor Viruses • Transformation: • Loss of growth control • Reduced adhesion • Motility • Invasion • Ability to form tumors - viral genes interfere with control of cell replication and other aspects of the cell phenotype • Transformed cells frequently exhibit chromosomal aberrations

15. Classes de genes que quando mutados causam transformação maligna • Oncogenes: Genes responsáveis pela transformação maligna de células (~100) A versão celular normal do oncogene é chamada de proto-oncogene (genes celulares homólogos de oncogenes que quando alterados (mutados) levam a transformação) • Anti-Oncogenes ou Supressores Tumorais: genes que quando deletados causam aparecimento de câncer (~10)

16. DNA Tumor Viruses In Human Cancer ONCOGENE A gene that codes for a protein that potentially can transform a normal cell into a malignant cell An oncogene may be transmitted by a virus in which case it is known as a VIRAL ONCOGENE v-onc c-onc X

17. RNA Tumor Viruses Proto-oncogene A cellular (host) gene that is homologous with a similar gene that is found in a transforming virus • A cellular oncogene can only induce transformation after • mutation • some other change in the cell’s genome

18. Fatores de crescimento Classes de proteínas que são codificadas por oncogenes Receptores de Fatores de crescimento Proteínas envolvidadas com a transdução de sinal Fatores de Transcrição

19. Oncogenes

20. Como surgiram os oncogenes retrovirais

22. DNA Tumor Viruses In Human Cancer • Papilloma Viruses • cause natural cancers in animals • cause benign warts • ubiquitous • epitheliotropic - most human tumors are malignancies of epithelial cells

23. DNA Tumor Viruses In Human Cancer • Papilloma Viruses • 51 types identified - most common are types 6 and 11 • Most cervical, vulvar and penile cancers are ASSOCIATED with types 16 and 18 (70% of penile cancers) EPIDEMIOLOGIAL STUDIES BUT: HPV 16 and HPV 18 do transform human keratinocytes Effective Vaccine (quadrivalent recombinant HPV 6, 11, 16 and 18 proteins made in yeast - Gardasil)

24. DNA Tumor Viruses In Human Cancer • Polyoma Viruses • Simian virus 40 - juvenile hamster sarcomas, transformation • contaminação de lotes de vacina contra polio • Polyoma - mouse leukemia, in vitro transformation • Human polyomas (JC and BK) - monkey sarcoma, transformation Possible association of BK with human prostate cancer Early functions are necessary - ONCOGENES

25. DNA Tumor Viruses In Human Cancer Adenoviruses Highly oncogenic in animals Always the same part Early functions E1A region: 2 T antigens E1B region: 1 T antigen E1A and E1B = Oncogenes

26. DNA Tumor Viruses In Human Cancer • Herpes Viruses • Considerable evidence for role in human cancer • Some very tumorigenic in animals

27. DNA Tumor Viruses In Human Cancer Epstein-Barr Virus • Burkitt’s Lymphoma • Endemic • Non-endemic • Nasopharyngeal cancer • Infectious mononucleosis (glandular fever) • Transforms human B-lymphocytes in vitro • Burkitt’s lymphoma: malarial infested regions • Nasopharyngeal cancer: China, SE Asia – diet?

28. DNA Tumor Viruses In Human Cancer Human herpes virus – 8 Kaposi’s Sarcoma Herpes Virus Kaposi’s sarcoma

29. Hepatitis B Virus DNA genome RNA polymerase II RNA Provirus Reverse transcriptase DNA genome DNA Tumor Viruses In Human Cancer Host enzyme Viral enzyme

30. DNA Tumor Viruses In Human Cancer • Epidemiology: • Strong correlation between HBV and hepatocellular carcinoma • China: 500,000 - 1 million new cases of hepatocellular carcinoma per year

31. virus virus RNA Tumor Viruses RNA Genome - Retroviruses RNA-dependent DNA Polymerase encoded by virus REVERSE TRANSCRIPTASE RNA genome Reverse transcriptase DNA genome Integrase Integrates Host RNA polymerase II RNA genome host

32. RNA Tumor Viruses A normal retrovirus has: 3 genes GAG : internal proteins ENV: Envelope glycoproteins POL: Enzymes Reverse transcriptase – RNase H Integrase Protease

33. RNA Tumor Viruses

34. RNA Tumor Viruses Retroviruses known to cause human cancer Human T cell lymphotropic virus -1 (HTLV-1) Adult T cell leukemia, Sezary T-cell leukemia Africa, Caribbean, Some Japanese Islands, S. America (Peru, Bolivia) 1-4% of infected people

35. Rous Sarcoma Virus R U5 GAG POL ENV U3 R Como retrovírus causam câncer? “typical retrovirus” R U5 GAG POL ENV U3 R SRC

36. Substituição de 19 aminoácidos do C-terminal por 12 aminoácidos diferentes

37. Some retroviruses have an oncogene instead of their regular genes Avian Myeloblastosis Virus R U5 GAG POL MYB U3 R Feline Sarcoma Virus (FSV) R U5 dGAG FMSdENV U3 R Avian Myelocytoma Virus (MC29) R U5 dGAGMYC dENV U3 R

38. Avian Leukosis Virus (causes lymphomas) R U5 GAG POL ENV U3 R RNA Tumor Viruses In contrast: No oncogene! – How does it cause a tumor?

39. RNA Tumor Viruses ALV can integrate into the host cell genome at MANY locations but in tumor it is always at the SAME site (or restricted number of sites)

40. RNA Tumor Viruses Could C-oncs be involved in NON-VIRAL cancers?

41. Cancers often result from gene translocations Burkitt’s Lymphoma 8:14 translocation Break in chromosome 14 at q32 myc Acute myelocytic leukemia7:159:1811:15:17

42. Oncogenesis by rearrangement Tumor c-onc new promotor Burkitt’s lymphoma myc (8) Ig heavy (8 to 14) Ig light (8 to 2) B-cell chronic lymphocytic bcl-1 Ig heavy (11 to 14) leukemia bcl-2 Ig heavy (18 to 14) T cell chronic lymphocytic tcl-1 T cell receptor leukemia (14 inversion) T cell chronic lymphocytic myc T cell receptor (8 to 14) leukemia

43. Anti-Oncogenes Retinoblastoma gene P53 have normal regulatory function in many cells

44. Anti-Oncogenes Retinoblastoma Adenovirus E1A Rb Gene Rb protein Rb 105kD Rb Rb Cell cycle continues Stops replication

45. Anti-Oncogenes p53 P53 gene P53 gene P53 gene Papilloma Hepatitis C P53 P53 P53 Papilloma proteolysis P53 DNA Stops replication replication replication

46. DNA Tumor VirusesOncogenes • Adenovirus E1A region 2 • SV 40 Large T • Polyoma Large T • BK virus Large T • Lymphotropic virus Large T • Human papilloma Virus-16 E7 • All have a sequence in common • Mutations in this region abolish transformation capacity

47. CANSEI!