Gerard Conrad Blobe, MD, PhD

Professor of Medicine
Professor of Pharmacology and Cancer Biology
Associate of the Duke Initiative for Science & Society
Member of the Duke Cancer Institute
Campus mail B354 Levine Science Research Center, 450 Research Drive, Durham, NC 27708
Phone (919) 668-6688

Our laboratory focuses on transforming growth factor-ß (TGF-ß) superfamily signal transduction pathways, and specifically, the role of these pathways in cancer biology. The TGF-ß superfamily is comprised of a number of polypeptide growth factors, including TGF-βs, bone morphogenetic proteins (BMPs) and activin) that regulate growth, differentiation and morphogenesis in a cell and context specific manner. TGF-ß and the TGF-ß signaling pathway have a dichotomous role in cancer biology, as both tumor-suppressor genes (presumably as regulators of cellular proliferation, differentiation and apoptosis) and as tumor promoters (presumably as regulators of cellular motility, adhesion, angiogenesis and the immune system). This dichotomy of TGF-ß function remains a fundamental problem in the field both in terms of understanding the mechanism of action of the TGF-ß pathway, and directly impacting our ability to target this pathway for the chemoprevention or treatment of human cancers. Resistance to the tumor suppressor effects of TGF-ß is also a common feature of epithelial-derived human cancers (breast, colon, lung, pancreatic, prostate), however, mechanisms for TGF-ß resistance remain undefined in the majority of cases. TGF-ß regulates cellular processes by binding to three high affinity cell surface receptors, the type I, type II, and type III receptors. Recent studies by our laboratory and others have established the type III TGF-ß receptor as a critical mediator/regulator of TGF-ß signaling. Specifically we have demonstrated that regulating type III TGF-ß receptor expression levels is sufficient to regulate TGF-ß signaling, and that decreased type III receptor expression is a common phenomenon in human cancers, resulting in cancer progression. The role of the type III TGF-ß receptor and type III TGF-ß receptor-interacting proteins in TGF-ß signaling and cancer biology and the epithelial to mesenchymal transition that occurs in human breast, colon and pancreatic cancers are currently being investigated using a multidisciplinary approach.
TGF-ß and the TGF-ß superfamily signaling pathways also have an important role in vascular biology. Indeed, mutations in two endothelial specific TGF-ß superfamily receptors, endoglin and ALK-1 (a type I receptor in the TGF-ß family), are responsible for the human vascular disease, hereditary hemorrhagic telangiectasia (HHT), and mice which lack expression of these receptors are embryonic lethal due to defects in angiogenesis. In addition, endoglin expression is potently up regulated during tumor-induced angiogenesis. In endothelial cells, TGF-ß signals through the type I TGF-ß receptor (ALK-5) or through ALK-1, to mediate opposing effects on endothelial cell proliferation and migration. However, the role of endoglin in regulating the balance in signaling between these pathways is unknown. Our laboratory has identified the nuclear hormone receptor, LXR-ß, as a protein that binds to activated ALK-1, is phosphorylated by ALK-1 and modulates ALK-1 signaling,establishing a novel signaling pathway downstream of ALK-1. Investigations in our laboratory have also revealed important functions for the cytoplasmic domain of endoglin, which is highly homologous to the cytoplasmic domain of the type III TGF-ß receptor. Studies are currently underway to further elucidate the signal transduction pathway downstream from these receptors and to establish their role in regulating tumor-induced angiogenesis. The ultimate goal of these studies is the ability to target the TGF-ß pathway for the chemoprevention or treatment of human cancers.
As endoglin and the type III TGF-ß receptors are both "co-receptors," a class of poorly understood cell surface receptors that bind ligand but are not thought to signal directly, another focus for the laboratory is establishing the role of these co-receptors in orchestrating signaling in physiological and pathophysiological settings.

Education and Training

  • Adult Oncology Fellow, Medicine, Dana Farber Cancer Institute, 1997 - 2000
  • Medical Resident, Medicine, Brigham and Women's Hospital, 1995 - 1997
  • Ph.D., Duke University, 1995
  • M.D., Duke University, 1995

Publications

Osborne, L. D., G. Li, E. O’Brien, G. C. Blobe, R. Superfine, and K. Mythreye. “TGF-beta regulates the Rho GEFs LARG and GEF-H1 during EMT to impact stiffening response to force and cell invasion.” Molecular Biology of the Cell 24 (2013).

Scholars@Duke

Uronis, Hope E., Johanna C. Bendell, Ivy Altomare, Gerard C. Blobe, S David Hsu, Michael A. Morse, Herbert Pang, et al. “A phase II study of capecitabine, oxaliplatin, and bevacizumab in the treatment of metastatic esophagogastric adenocarcinomas..” Oncologist 18, no. 3 (2013): 271–72. https://doi.org/10.1634/theoncologist.2012-0404.

PMID
23485624
Full Text

Mythreye, K., E. H. Knelson, C. E. Gatza, M. L. Gatza, and G. C. Blobe. “TβRIII/β-arrestin2 regulates integrin α5β1 trafficking, function, and localization in epithelial cells.” Oncogene 32, no. 11 (2013): 1416–27. https://doi.org/10.1038/onc.2012.157.

Full Text

Tian, Hongyu, Karthikeyan Mythreye, Christelle Golzio, Nicholas Katsanis, and Gerard C. Blobe. “Endoglin mediates fibronectin/α5β1 integrin and TGF-β pathway crosstalk in endothelial cells..” Embo J 31, no. 19 (October 3, 2012): 3885–3900. https://doi.org/10.1038/emboj.2012.246.

PMID
22940691
Full Text

Lee, Nam Y., Christelle Golzio, Catherine E. Gatza, Arun Sharma, Nicholas Katsanis, and Gerard C. Blobe. “Endoglin regulates PI3-kinase/Akt trafficking and signaling to alter endothelial capillary stability during angiogenesis..” Molecular Biology of the Cell 23, no. 13 (July 2012): 2412–23. https://doi.org/10.1091/mbc.E11-12-0993.

PMID
22593212
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Vlahovic, Gordana, Kellen L. Meadows, Hope E. Uronis, Michael A. Morse, Gerard C. Blobe, Richard F. Riedel, S Yousuf Zafar, et al. “A phase I study of bevacizumab, everolimus and panitumumab in advanced solid tumors..” Cancer Chemother Pharmacol 70, no. 1 (July 2012): 95–102. https://doi.org/10.1007/s00280-012-1889-8.

PMID
22638798
Full Text

Hanks, Brent Allen, Alisha Holtzhausen, Petra Gimpel, Rebekah Jamieson, Olivia M. Campbell, Lihong Sun, Christina K. Augustine, et al. “Effect of the loss of the type III TGF beta receptor during tumor progression on tumor microenvironment: Preclinical development of TGF beta inhibition and TGF beta-related biomarkers to enhance immunotherapy efficacy..” In Journal of Clinical Oncology, Vol. 30. AMER SOC CLINICAL ONCOLOGY, 2012.

Scholars@Duke

Morse, Michael, Amy Hobeika, Arvind Chaudhry, Andrea Amalfitano, Donna Niedzwiecki, Timothy M. Clay, Takuya Osada, et al. “Effect of the vaccine Ad5 [E1-, E2b-]-CEA(6D) on CEA-directed CMI responses in patients with advanced CEA-expressing malignancies in a phase I/II clinical trial.” In Journal of Clinical Oncology, Vol. 30. AMER SOC CLINICAL ONCOLOGY, 2012.

Scholars@Duke

Holtzhausen, Alisha, Tam How, Bradley C. Gersh, and Gerard C. Blobe. “Abstract 3035: Bone morphogenetic proteins signal through Smad2 and Smad3 to regulate cell migration and proliferation.” Molecular and Cellular Biology, April 15, 2012. https://doi.org/10.1158/1538-7445.am2012-3035.

Full Text

Townsend, Todd A., Jamille Y. Robinson, Tam How, Daniel M. DeLaughter, Gerard C. Blobe, and Joey V. Barnett. “Endocardial cell epithelial-mesenchymal transformation requires Type III TGFβ receptor interaction with GIPC..” Cell Signal 24, no. 1 (January 2012): 247–56. https://doi.org/10.1016/j.cellsig.2011.09.006.

PMID
21945156
Full Text

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