Kathryn B. Horwitz, Ph.D.
University Distinguished Professor Emerita
Dr. Horwitz came to Colorado in 1979 from the University of Texas Southwestern Medical School. Research in her laboratory of approximately 15 people focuses the role of estradiol and progesterone, and antiestrogens and antiprogestins, on breast cancer growth and treatment, cancer metastasis and cancer stem cells. Long-term goals are to improve the strategies and outcomes of hormone therapies. Research topics are: transcriptional mechanisms of progesterone receptors and role of SUMOylation; hormones in cancer growth; mechanisms of hormone and chemotherapy resistance; hormones and cancer stem cells in metastasis; the metastatic microenvironment and malignant stroma in tumor biology; development of new breast cancer models; translation of laboratory findings into clinical studies and practice. She has mentored numerous graduate students, as well as clinical and post-doctoral fellows. She is a well known national and international scholar and recently served as President of the Endocrine Society.
- Jacobsen BM, Jambal P, Schittone SA, Horwitz KB. ALU repeats in promoters are position-dependent co-response elements (coRE) that enhance or repress transcription by dimeric and monomeric progesterone receptors. Mol Endocrinol. 2009 Jul;23(7):989-1000. PUBMED
- Abdel-Hafiz H, Dudevoir ML, Horwitz KB. Mechanisms underlying the control of progesterone receptor transcriptional activity by SUMOylation. J Biol Chem. 2009 Apr 3;284(14):9099-108. PUBMED
- Horwitz KB. The Year in Basic Science: update of estrogen plus progestin therapy for menopausal hormone replacement implicating stem cells in the increased breast cancer risk. Mol Endocrinol. 2008 Dec;22(12):2743-50. PUBMED
- Horwitz KB, Sartorius CA. Progestins in hormone replacement therapies reactivate cancer stem cells in women with preexisting breast cancers: a hypothesis. J Clin Endocrinol Metab. 2008 Sep;93(9):3295-8. PUBMED
- Lange CA, Sartorius CA, Abdel-Hafiz H, Spillman MA, Horwitz KB, Jacobsen BM. Progesterone receptor action: translating studies in breast cancer models to clinical insights. Adv Exp Med Biol. 2008;630:94-111. PUBMED
- Singh M, Spoelstra NS, Jean A, Howe E, Torkko KC, Clark HR, Darling DS, Shroyer KR, Horwitz KB, Broaddus RR, Richer JK. ZEB1 expression in type I vs type II endometrial cancers: a marker of aggressive disease. Mod Pathol. 2008 Jul;21(7):912-23. PUBMED
- Horwitz KB , Dye WW, Harrell JC, Kabos P and Sartorius CA. Rare steroid receptor negative basal-like tumorigenic cells in luminal subtype human breast cancer xenografts, Proc Nat Acad Sci, 105(15): 5774-5779, 2008 PUBMED
- Horwitz KB and Sartorius CA. COMMENTARY: Progestins in hormone replacement therapies reactivate cancer stem cells in occult breast cancers: a hypothesis. J Clin Endo & Metab. 2008 PUBMED
- Harvell DM, Spoelstra NS, Singh M, Finlayson C, Phang T, Hunter L, Dye WW, Borges VB, Elias AD, Horwitz KB and Richer JK. Molecular signatures of response to neoadjuvant endocrine therapies for breast cancers. Breast Cancer Research & Treatment, 2008 PUBMED
- Harvell DM, Richer JK, Singh M, Spoelstra N, Finlayson C, Borges VB, Elias AD and Horwitz KB. Estrogen regulated gene expression in response to neoadjuvant endocrine therapy of breast cancers: Tamoxifen agonist effects dominate in the presence of an aromatase inhibitor. Breast Cancer Research & Treatment, 2008 PUBMED
- Singh M, Spoelstra NS , Howe JA, Torkko KC, Clark HR, Darling DS, Shroyer KK, Horwitz KB , Broaddus RR and Richer JK. ZEB1 expression in Type I vs. Type II endometrial cancers: a marker of aggressive disease. Modern Pathology, 21: 912-923, 2008. PUBMED
- Breast Cancer