Research Programs: Genetic Mechanisms of Cancer, Tumor Biology and Progression
Assistant Professor, Department of Neurosurgery, Director of Department of Neurosurgery Gene Therapy Program and Gene and Stem Cell Core Facility

ohlfe001@umn.edu
612-626-2491 — office
612-624-1195 — lab
Preferred method of contact: e-mail

Dr. Ohlfest studied molecular biology Iowa State University and received his B.S. in 2001. He received his Ph.D. at the University of Minnesota in 2004 working on gene therapy approaches to treating malignant gliomas. He joined the faculty of the department of neurosurgery in 2005 and leads their gene therapy program.

Research Interests

There are several projects being aggressively pursued in our laboratory, all of them focused on brain tumors.

Immunotherapy: Toll-like receptor agonists as vaccine adjuvants
Toll-like receptors agonists such as CpG Oligodeoxynucleotides (ODN) are potent vaccine adjuvants. We have developed dendritic cell-culture free personalized vaccines by vaccination with tumor lysate mixed with CpG ODN in vivo. This is a translational project focused on issues of dose, antigen source, timing, route, and frequency of vaccinations in murine models and dogs with spontaneous glioma. These data have been instrumental in designing evidence-based vaccination strategies for our human trial in 2009 and those pending.

In addition the time dynamics of T cell, NK cell, and dendritic cell trafficking into the tumor site induced by vaccination is being determined. For these studies we use adoptively transferred luciferase transgenic cells and in vivo imaging, flow cytometry of brain infiltrating lymphocytes, or adoptive transfer of antigen specific T cells.

Characterizing the phenotype of glioma stem cells using in vitro and in vivo models
This is a basic biology project employing novel spontaneous murine models and primary human cell cultures. We are interrogating requirements for self renewal including supportive niches and determining the genetic basis for disease maintenance.

Nonviral and adenoviral vector targeting to tumor cells, employing immuno-gene therapy
This is a translational project testing the safety and efficacy of microenvironment modulation with "tumor seeking" stem cell vectors given I.V. or viral vectors delivered at the tumor site. While currently in murine models, we feel these approaches have a strong potential for clinical use in the foreseeable future.

Transgenic and somatic cell gene transfer-based glioma model
We recently developed a novel method to induce spontaneous glioma in the mouse using nonviral transfection. Using this flexible and simple system, everything from preclinical trials to basic biology investigations are being carried out.

Blood brain barrier and cancer stem cell drug efflux
Drug efflux transporters prevent many drugs from reach the infiltrating tumor edge that is frequently a source of recurrence. This is a critical and often overlooked reason for the failure of small molecule drugs to effectively treat glioma, due to the invasive "whole brain" nature of this disease. We are employing genetic knockouts and pharmacologic agents to inhibit these efflux proteins to improve clinical efficacy in murine models.

Hollow fiber catheter technology for convection enhanced delivery (CED)
CED is a promising method for drug delivery into the brain that utilizes bulk flow to drive infusate into large volumes of tissue. However, many clinical traisl conduted thus far have revealed that catheter design is completely inadequate to achieve clinically meaningful drug delivery. In collaboration with Twin Star Medical Inc. we have developed hollow fiber catheters that dramatically improve the distribution of infusate in the brain, but also reduce backflow that has been associated with toxicity and limited efficacy. These results were first published in mouse brain but human scale catheters are now being validated in large animals and are expected to enter clincial trials soon.

Selected Publications

Ohlfest JR, Lobitz PD, Perkinson SG, and Largaespada DA. Integration and long-term expression in xenografted human glioblastoma cells using a plasmid-based transposon system. Mol Ther. 2004;10:260-268.

Ohlfest JR, Frandsen JL, Fritz S, Lobitz PD, Perkinson SG, Clark KJ, Nelsestuen G, Key NS, McIvor RS, Hackett PB, Largaespada DA. Phenotypic correction and long-term expression of factor VIII in hemophilic mice by immunotolerization and nonviral gene transfer using the Sleeping Beauty transposon system. Blood 2005;105:2691-2698.

Ohlfest JR, Demorest ZL, Mootoka Y, Vengco I, Oh S, Chen E, Scappaticci FA, Saplis RJ, Ekker SE, Low WC, Freese AB, and Largaespada DA. Combinatorial antiangiogenic gene therapy by nonviral gene transfer using the sleeping beauty transposon causes tumor regression and improves survival in mice bearing intracranial human glioblastoma. Mol Ther. 2005 ;12:778-788.

Ohlfest JR, Freese AB, and Largaespada DA. Nonviral vectors for cancer gene therapy: prospects for integrating vectors and combination therapies. Curr Gene Ther. 2005;5:629-641.

Wu A, Xiao J, Chen W, Hall WA, Low WC, and Ohlfest JR. Expression of MHC I and NK ligands on human CD133(+) glioma cells: possible targets of immunotherapy. J Neurooncol. 2007;83;121-131.

Oh S, Pluhar EG, McNeil EA, Kroeger KM, Liu C, Castro MG, Lowenstein PR, Freese A, Ohlfest JR. Efficacy of nonviral gene transfer into the canine brain. J Neurosurg. 2007;107:136-144.

Wu A, Oh S, Ericson K, Demorest ZL, Vengco I, Gharagozlou S, Chen W,Low WC, and Ohlfest JR. Transposon-based interferon gamma gene transfer overcomes limitations of episomal plasmid for immunogene therapy of glioblastoma. Cancer Gene Ther. 2007;14:550-560.

Wu A, Oh S, Gharagozlou S, Vedi RN, Ericson K, Chen W, Low WC, and Ohlfest JR. In vivo vaccination with tumor cell lysate plus CpG oligodeoxynucleotides eradicates murine glioblastoma. J Immunother. 2007;30:789-797.

Wu A, Oh S, Ericson K, Chen L, Hall WA, Champoux PE, Low WC, and Ohlfest JR. Persistence of CD133+ cells in human and mouse glioma cell lines: detailed characterization of GL261 glioma cells with cancer stem cell-like properties. Stem Cells Dev. 2008;17:173-84.

Xiong Z, Gharagozlou S, Vengco I, Chen W and Ohlfest JR. 2008. Effective CpG immunotherapy of breast carcinoma prevents but fails to eradicate established brain metastasis. 2007 Clin Cancer Res., in press.