Understanding Oncogenic Transcription Factors and the Role of p-STAT3
Cellular biology depends upon signaling mechanisms to regulate functions such as cell growth, death and adaptation. Signal “transduction” is such a mechanism that converts an upstream stimulus to a cell into a specific cellular response. Signal transduction starts with a signal to a receptor or via a compound capable of passing through the cell membrane and ends with a change in cell function. The result of this signal is often the activation of “transcription,” whereby genetic information is expressed, and in the case of oncogenic transcription, disease processes are initiated or maintained.
Receptors span the cell membrane, with part of the receptor outside and part inside the cell. When a chemical signal represented by a specific protein binds to the outer portion of the receptor, it conveys another signal inside the cell. Often there is a cascade of signals within the cell, wherein an upstream inducer starts a chain of events that resembles a domino effect. Collectively, this sequence is referred to as a “signaling pathway.” Eventually, the signal creates a change in the cell function by changing the expression of specific genes and production of specific proteins within the cell, and again, in the case of tumor development, such expression results in unwanted oncogenic processes.
Importantly, while normal healthy cell function relies on signaling mechanisms, diseases can co-opt these mechanisms with negative consequences. Oncogenic processes (including inflammation and proliferation) depend upon signaling pathways that are responsible for coordinating functions such as cell growth, survival and cell differentiation. A particular class of proteins referred to as Signal Transducers and Activators of Transcription (such proteins are “STATs”) regulates the process of disease cell survival and proliferation, angiogenesis and immune system function and is persistently activated in a large number of human inflammatory processes and in hyper-proliferating diseases. Because certain of these proteins are known to be co-opted by tumor cells, we refer to them as “oncogenic transcription factors,” of which certain STATs are a subset.