Differentiation modifiers.

This article summarizes evidence that indicates that a variety of relatively simple chemical compounds can induce murine erythroleukemia cells (MELCs) as well as a number of other transformed cell lines to differentiate with the loss of proliferative capacity and the expression of differentiated characteristics. These studies provide a potentially important new approach in the treatment of certain neoplastic diseases that may be an alternative to the use of cytotoxic agents, namely, agents that induce transformed cells to terminal cell division, expression of differentiated characteristics, and loss of oncogenic properties. A strong note of caution is needed concerning the potential therapeutic role of these agents that are able to induce transformed cells to terminal differentiation. In general, it appears that inducer-sensitive transformed cell lines are blocked at a particular stage in the development of these cells. The evidence suggests that these compounds trigger certain events that then are involved in the progression of differentiation of these cells with loss of proliferative capacity. It is not known how to predict which transformed cell lines are blocked in a stage of differentiation susceptible to the inducer-mediated effects of agents as described above. Nevertheless, it is reasonable to suggest that the pursuit of studies in this area may permit researchers to determine the potential efficacy of these inducers for in vivo controlled trials with certain select types of neoplasms.