John A. Katzenellenbogen


Dr. Katzenellenbogen’s research spans chemistry, biology, and medicine, and involves analysis of steroid receptor structure and function, and use of receptors and their ligands in various biological and biomedical applications. He prepared the first affinity labels for the estrogen receptor (ER), and using X-ray crystallography and molecular modeling as a guide, he has developed modular methods for the synthesis of non-steroidal estrogens, adaptable to combinatorial approaches, through which he has prepared a number of estrogens of novel structure that are highly selective for only one of the two ER subtypes, ERα of ERβ. Because these receptors have different tissue distributions and different biological functions, these ER subtype-selective ligands are proving to be very useful as pharmacological probes of the functions of the two different ERs, with potential applications to hormonal therapies of breast and prostate cancers. He has also diversified the structure and elemental composition of ER ligands, introducing three-dimensional core elements that engender antiproliferative and anti-inflammatory activities. He has designed estrogen conjugates that selectively activate extranuclear-initiated ER action that show selective cardiovascular protection without affecting reproductive organs or breast tumors, thereby minimizing risk of promoting cancer at these sites. Other ligands he has developed have shown unexpected biological selectivities that could be medically important as neuroprotective and antitumor agents. He is working on novel ligands to block estrogen action through second-site inhibition.

To assist in the selection of patients for endocrine therapies directed at steroid receptors in breast and prostate cancers, he has developed high affinity receptor ligands, labeled with the positron-emitting radionuclide fluorine-18, for positron emission tomographic (PET) imaging of these tumor receptors. He has also assisted in the development of a PTE-based hormone challenge test which images hormone-induced changes in tumor metabolism that is proving highly predictive of response to endocrine therapies in breast cancer. Thus, throughout his career in research, the estrogen receptor has been for him a true locus for the interplay of medicinal chemistry, structural biology, and biomedicine.


Breast Cancer, Prostate Cancer, PET Imaging, Estrogen Receptor, Progesterone Receptor, Androgen Receptor, SERMs, Selective Estrogens

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*University of Illinois Cancer Center Member