uitre ages tor severa dysons③ Growth of cells is restricted by propertes 8 of individual tissue 28.1 Introduction jority of cells die: a few cells⑨g grow o Immortalizatio Established cell line divides but cells continue m adhere to substratum equire serum, and are bited by contact o Figure 28. 1 Three types of properties distinguish a cancer Transfom ation Transformed cells are independe of anchorage, serum, contact cell from a normal cell inhi bition: change shape, round up. and grow into a focus Sequential changes in cultured cells can be correlated with Transformed cells may form solid tumor changes in tumorigenicity NOw fully tumorigenic, cells become mobile and can migrate to start new colonies 消当 Tumors form at new locations
Figure 28.1 Three types of properties distinguish a cancer cell from a normal cell. Sequential changes in cultured cells can be correlated with changes in tumorigenicity. 28.1 Introduction
28.1Introduction Normal cells Transformed cells 遇 Figure 28.2 Normal fibroblasts grow as a layer of flat, spread-out cells, whereas transformed fibroblasts are rounded up and grow in cell masses. The cultures on the left contain normal cells, those on the right contain transformed cells. The top views are by conventional microscopy, the bottom by scanning electron microscopy Photographs kindly provided by Hidesaburo Hanafusa and J. Michael Bishop 消当
Figure 28.2 Normal fibroblasts grow as a layer of flat, spread-out cells, whereas transformed fibroblasts are rounded up and grow in cell masses. The cultures on the left contain normal cells, those on the right contain transformed cells. The top views are by conventional microscopy, the bottom by scanning electron microscopy. Photographs kindly provided by Hidesaburo Hanafusa and J. Michael Bishop. 28.1 Introduction
28.2 Transforming viruses carry oncogenes Mral Class Genome Genome Size Oncogenes Origin of Oncogene Action of Oncogene Pol yoma csDNA 5-6kb T antigens Early viral gene inactivates tumar suppressor HPY dDN鸟 8 kb E6&E7 Early viral gene inactivates tumar suppressor Adeno csDN 37kb E1A&ElB Early viral gene activates tumor suppressor Retrovirus ssRNA 6-9 kb Indi vidual Cellular activates oncogenic pathway acute) Figure 28.3 Transforming viruses may carry oncogenes 消当
Figure 28.3 Transforming viruses may carry oncogenes. 28.2 Transforming viruses carry oncogenes
Productiv e infection Transformation 28.2 Transforming (in permissi e cells)(nonpermissive cells) viruses carr Early infe ction Abortiv e infe ction oncogenes Entry and VIrus enters production of virus components Figure 28.4 Permissive cells o Late infection Inte gration Replication Viral DNA are productively infected by S and assembly becomes part of particles of host genom a dna tumor virus that enters the lytic cycle, while nonpermissive cells are LySis Transformation Cell de ath Cells change transformed to change their and release shape and of viruses 「W phenotype 消当
Figure 28.4 Permissive cells are productively infected by a DNA tumor virus that enters the lytic cycle, while nonpermissive cells are transformed to change their phenotype. 28.2 Transforming viruses carry oncogenes
28.2 Transforming ear late viruses carr s40 oncogenes Infection Adenovirus ear late Figure 28.5 Cells AMA transformed by polyomaviruses or Host dNa adenoviruses have viral Integrated sequences that include the 八 AAVA early region integrated into the cellular genome. Sites of Transforming integration are random onco otein Sv40 T/t antigens Adenovirus E1A, E1B 消当
Figure 28.5 Cells transformed by polyomaviruses or adenoviruses have viral sequences that include the early region integrated into the cellular genome. Sites of integration are random. 28.2 Transforming viruses carry oncogenes