RESUMO
Cancer is a complex disease characterized by a loss in the normal cell regulatory mechanisms that govern cell survival, proliferation, and differentiation. Current chemotherapeutics, as anticancer agents, are developing resistance to single drug and also to treatment therapies involving multiple drugs. Cross resistance associated with the specificity and selectivity of existing drugs has restricted the application of chemotherapy. Alternatively, these limitations have given better insight in understanding the underlying molecular mechanisms responsible for the development of various stages in cancer. In the light of this, continuous efforts are being made in order to identify and validate newer anticancer targets. This review presents some of the important targets that have been already reported, such as aromatase, farnesyl transferase, histone deacetylase, tyrosine kinase and cyclin-dependent kinase. A few molecules designed against these targets have successfully reached clinical trials. However, only limited marketed drugs are available from these classes. Besides, the review also highlights some of the other important targets and strategies that have also drawn considerable attention in the area of anticancer drug development such as, cancer stem cells and monoclonal antibodies. Further, the integration of the tools in molecular biology with the results from preclinical and clinical trials would strengthen the effectiveness of treatment regimens in cancer patients. There lies a much scope for designing promising lead compounds and treatment therapies against these established targets.