癌基因介绍.ppt

Gene and Disease Yuan Ping OncogeneTumor Suppressor Genes Growth Factors Cancer cells are characterized by : Diminished or unrestrained control of growth; Invasion of local tissues; Spread, or metastasis, to other parts of the body. Growth out of control Growth out of control Growth out of control Ignore growth inhibition Spread, or metastasis, to other parts of the body Metastasis is the most dangerous property of tumor cells. Angiogenesis Carcinogeneic agents (Carcinogens) Physical agents: UV, x-ray, γ-ray Chemical agents: benzene, asbestos, aflatoxin, Biological agents: some DNA and RNA viruses Personal factors: immunity, inherited characteristic Section I Oncogenes Oncogenes are intracellular genes that control cell growth and differentiation, the abnormity of structure or expression of oncogenes causes cancer. Oncogenes were initially identified as genes carried by viruses that cause transformation of their target cells. The oncogenes found in the cellular DNA, are called proto-oncogenes, pro-onc. Two types of oncogenes: Viral oncogenes (v-onc) Cellular oncogenes (c-onc) Viral oncogenes (v-onc) Tumor viruses: DNA viruses , RNA viruses Viral oncogenes are the genes existed in tumor viruses (specially in retroviruses) and make target cells transformed. Retrovirusus cause tumors in two general ways: i. The virus itself carry a gene whose product alters the control of cell proliferation. Cellular oncogenes (c-onc) c-onc are necessary for the cell. c-onc control cell growth and differentiation. Alteration of structure or expression of oncogenes are tumorigenic. Characteristics of c-onc Wildly distributed in the biology; Highly conserved in gene sequence; Gene products (proteins) are necessary for maintaining normal cellular functions, regulation cell growth and differentiation; Activation of c-one will cause malignant transformation. Products of c-one Growth factors Receptors of growth factors Intracellular signal transductors: non-RTK, serine/threonin