Suppression of apoptosis: role in cell growth and neoplasia

A cell is a potentially dangerous thing. In unicellular organisms, cells di vide and multiply in a manner that is chiefly determined by the availabilit y of nutritional substrates. In a multicellular organism, each cell has a d istinct growth potential that is designed to subsume a role in the function of the whole body. Departure from this path to one of uncontrolled cellula r proliferation leads to cancer. For this reason, evolution has endowed cel ls with an elaborate set of systems that cause errant cells to self-destruc t. This process of cell suicide is known as apoptosis or programmed cell de ath and it plays a crucial role in the growth of both normal and malignant cells. In this review, we describe the mechanisms whereby programmed cell d eath is induced and executed. In particular, we concentrate on how anti-apo ptotic signals generated by cytokines promote cell survival and how these s ignal transduction pathways may be involved in the pathogenesis of neoplasi a. Understanding how these processes contribute to tumorigenesis may sugges t new therapeutic options.