Worldwide, cancer is a leading cause of death. Cancers can be viewed as a breakdown in the communication between tumor cells and their environment, including their normal neighboring cells. Growth-stimulatory and growth-inhibitory signals are routinely exchanged between cells within a tissue. Normally, cells do not divide in the absence of stimulatory signals or in the presence of inhibitory signals. In a cancerous or neoplastic state, a cell acquires the ability to “override” these signals and to proliferate under conditions in which a normal cell would not.
Presently, few cures exist for treating the various types of cancer. Among the possible cures that do exist include the application of tumor-inhibiting compounds (chemotherapy), radiation therapy, and bone-marrow transplants. Chemotherapy treatments typically include the application of chemotherapeutic agents to a patient in selected dosages to achieve and maintain a therapeutically effective level of the agents in the patient. However, most known chemotherapeutic agents used for the treatment of cancer display significant side effects. Thus, a drawback of typical chemotherapy treatments is that the compounds employed are non-specific in their activity and accumulate to toxic levels, and hence kill rapidly proliferating normal cells, as well as tumor cells. Furthermore, often a therapeutic agent that is initially effective for a given patient becomes, over time, ineffective or less effective for that patient. Further, a therapeutic agent that is effective, at least initially, for some patients can be completely ineffective or even harmful for other patients.
Accordingly, it would be useful to identify compounds that sensitize cancer cells, to conventional chemotherapy such that the therapeutic effect of any given chemotherapeutic agent is maximized. Such compounds would ideally also reduce the required dosage of the chemotherapeutic agent thereby resulting in fewer side effects in the patient.