Cellular death-by-suicide is part of normal development, and is termed apoptosis or programmed cell death (PCD). Cysteine Aspartate Specific ProteASEs - caspases - are active in apoptosis, as are p53, a tumor suppressor gene, and FAS gene, which is member 6 of the tumor necrosis factor receptor superfamily (TNF). In contrast to apoptosis, necrosis is cell death that results from cytotoxic, injurious stresses that are too severe for correction by the cellular stress response. Apoptosis is a part of normal cell turnover and tissue homeostasis „History" of molecular biology of cell death ^Kerr et al., 1972: Identification of the cell death APOPTOSIS Kerr, Wylie and Currie Apoptosis: a basic biological pehenomenon with wide-ranging implications in tissue kinestics. Br. J.Cancer 1972;26:239-257 1990 Horvitz (1992-3) identification of „cell death genes" in Caenorhabditis elegans { ced-3 (ICE), ced-4 (0), ced-9 (bc/-2)} (Cerretti 1992, Thornberry 1992) uncovering of the homology between ced-3 gene product and ICE (interleukin-lß converting enzyme)] protease Discovery of new family of mammalian cysteine proteases - CASPASES Apoptosis is involved in a wide range of physiological and pathological processes. > Development (embryonic, neuronal development) > Inflammation and involution of tissues > In the immune system (Apoptosis is employed as a method of cytotoxic T-cell mediated killing of infected cells) > In ageing Apoptosis plays a pivotal role in the pathophysiology of a g\ The free radical theory of ageing links senescence to damage inflicted by superoxide-derived adicals and other oxidants generated primarily in mitochondrial respiration. The i g, proposes that ageing is the resul mitochondrial DNA (mtDNA). The accumulation of errors in mtDNA leads to errors in , i.e., the four mitochondrial enzymatic complexes. Defective complexes produce more free radicals leading to a vicious cycle of increasing mtDNA damage, radical generation, and possibly apoptosis Apoptosis in contrast to necrotic cell death reversible swelling mitochondrial morphological changes chromatin pattern conserved irreversible swelling membrane breakdown U y DNA fragments nuclear changes intact membranes apoptotic bodies condensation (cell blebbing) fragmentation secondary necrosis Roche: Cell Death - Apoptosis and Necrosis Nuclear morfology in HL-60 cells (P. Mlejnek 2001) I) < n) áfe fM* r íl HI) . • I) Control II) Apoptosis *##* III) Necrosis Cell death classification by Clarke Apoptosis Autophagy - heterophagy, final cell destruction is done by lysosomes of other cells - final cell destruction is done by its own lysosomes Nonlysosomal - cell destruction is mediated by disintegration unknown nonlysosomal proteases í is a form of programmed cell death which is induced by anchorage-dependent cells detaching from the surrounding extracellular matrix (ECM)[1]. Usually cells stay close to the tissue to which they belong since the communication between proximal cells as well as between cells and ECM provide essential signals for growth or survival. When cells are detached from the ECM, i.e. there is a loss of normal cell-matrix interactions, they may undergo anoikis. However, metastatic tumor cells may escape from anoikis and invade other organs. Two major apoptotic pathways in mammalian cells *9