ABSTRACT

Cells in multicellular organisms can kill themselves by activating a suicidal genetic program in response to a wide variety of signals, including hormones, cytokines, ionizing radiation, and chemotherapeutic agents. The process of this cell suicide is called ‘apoptosis’, which usually occurs under physiological conditions [1-6]. This type of cell death is considered to be different from necrosis, which is the result of severe injury. The phenomenon of apoptosis has long been known as ‘programmed cell death’, which is fundamental for embryonic development, such as in metamorphosis, morphogenesis and synaptogenesis [5-7]. It also occurs in many adult tissues in normal cell turnover, thymic negative selection, cell mediated cytotoxicity, and so on [1-4, 6, 14, 22-24].