Steroid receptors as molecular targets for cancer diagnosis and therapy

The targeted delivery of chemotherapeutics is essential to minimizing the side effects by sparing the normal tissues by exposure to cytotoxic agents. The various receptors are overexpressed on the surface of the tumor tissues as compared to the normal tissues because their requirement for various essential components is high for the growth and development of tumor tissues. These overexpressed receptors on the tumor surface have been investigated for selective delivery of imaging, cytotoxic, or other therapeutic agents. Hormonal receptors viz. peptide and steroid receptors (SRs), which are present over the tumor surface, are also used for tumor targeting of various molecules for therapeutic use or imaging purpose. The key role of SRs is in the transactivation step of protein synthesis and to maintain the homeostasis in normal and diseased states. These receptors are overactivated in different diseases, including tumorigenesis. Hence, these SRs may act as a potential target for selective delivery of different therapeutic or cytotoxic agents. The selective delivery of these agents may be a better treatment strategy for endocrine cancer because it results in cytosolic and nuclear delivery of cytotoxic agents as well. The objective of the present review is to explore the importance of sex SRs as a vital target in endocrine cancer therapy. Potential strategies investigated for the delivery of imaging agents, chemotherapeutics, and toxins via steroidal ligands have been discussed. The importance of gene therapy in different diseases, including endocrine cancer, is well defined; thus, some effective gene delivery approaches investigated in endocrine cancer via steroidal ligands have also been discussed.