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1.  Enhanced Effector Responses in Activated CD8+ T Cells Deficient in Diacylglycerol Kinases 
Cancer research  2013;73(12):3566-3577.
Recent clinical trials have shown promise in the use of chimeric antigen receptor(CAR)-transduced T cells; however, augmentation of their activity may broaden their clinical utility and improve their efficacy. We hypothesized that, since CAR action requires proteins essential for TCR signal transduction, deletion of negative regulators of these signaling pathways would enhance CAR signaling and effector T cell function. We tested CAR activity and function in T cells that lacked one or both isoforms of diacylglycerol kinase (dgk) expressed highly in T cells, dgkα and dgkζ, enzymes that metabolize the second messenger diacylglycerol (DAG) and limit Ras/ERK activation. We found that primary murine T cells transduced with CARs specific for the human tumor antigen mesothelin demonstrated greatly enhanced cytokine production and cytotoxicity when co-cultured with a murine mesothelioma line that stably expresses mesothelin. Additionally, we found that dgk-deficient CAR-transduced T cells were more effective in limiting the growth of implanted tumors, both concurrent with and after establishment of tumor. Consistent with our studies in mice, pharmacologic inhibition of dgks also augments function of primary human T cells transduced with CARs. These results suggest that deletion of negative regulators of TCR signaling enhances the activity and function of CAR-expressing T cells and identify dgks as potential targets for improving the clinical potential of CARs.
PMCID: PMC3686869  PMID: 23576561
diacylglycerol kinase; chimeric antigen receptor; T cell receptor; tumor; mesothelin
2.  Overcoming intrinsic inhibitory pathways to augment the antineoplastic activity of adoptively transferred T cells 
Oncoimmunology  2013;2(11):e26492.
Effector T cells become rapidly inactivated after antigen exposure due to extracellular as well as intrinsic signals. We have recently demonstrated that the deletion of diacylglycerol kinases, intrinsic inhibitors of T-cell signaling, enhances the activity of adoptively transferred T cells expressing a chimeric antigen receptor (CAR) specific for a tumor-associated antigen.
PMCID: PMC3897565  PMID: 24490126
Chimeric Antigen Receptor; T cell hypofunction; diacylglycerol kinase; tumor immunosuppression; tumor microenvironment
3.  Expression of a Functional CCR2 Receptor Enhances Tumor Localization and Tumor Eradication by Retargeted Human T Cells Expressing a Mesothelin - Specific Chimeric Antibody Receptor 
Adoptive T cell immunotherapy (ACT) with tumor infiltrating lymphocytes or genetically-modified T cells has yielded dramatic results in some cancers. However, T cells need to traffic properly into tumors in order to adequately exert therapeutic effects.
Experimental Design
The chemokine CCL2 was highly secreted by malignant pleural mesotheliomas (MPM) (a planned tumor target), but the corresponding chemokine receptor (CCR2) was minimally expressed on activated human T cells transduced with a chimeric antibody receptor (CAR) directed to the MPM tumor antigen mesothelin (mesoCAR T cells). The chemokine receptor CCR2b was thus transduced into mesoCAR T cells using a lentiviral vector and the modified T cells were used to treat established mesothelin-expressing tumors.
CCR2b transduction led to CCL2-induced calcium flux and increased transmigration, as well as augmentation of in vitro T cell killing ability. A single intravenous injection of 20 million mesoCAR + CCR2b T cells into immunodeficient mice bearing large, established tumors (without any adjunct therapy) resulted in a 12.5-fold increase in T cell tumor infiltration by Day 5 compared to mesoCAR T cells. This was associated with significantly increased anti-tumor activity.
CAR T cells bearing a functional chemokine receptor can overcome the inadequate tumor localization that limits conventional CAR targeting strategies and can significantly improve anti-tumor efficacy in vivo.
PMCID: PMC3612507  PMID: 21610146
4.  A Trial of Intrapleural Adenoviral-mediated Interferon-α2b Gene Transfer for Malignant Pleural Mesothelioma 
New therapeutic strategies are needed for malignant pleural mesothelioma (MPM). We conducted a single-center, open-label, nonrandomized, pilot and feasibility trial using two intrapleural doses of an adenoviral vector encoding human IFN-α (Ad.IFN-α2b). Nine subjects were enrolled at two dose levels. The first three subjects had very high pleural and systemic IFN-α concentrations resulting in severe “flu-like” symptoms necessitating dose de-escalation. The next six patients had reduced (but still significant) pleural and serum IFN-α levels, but with tolerable symptoms. Repeated vector administration appeared to prolong IFN-α expression levels. Anti-tumor humoral immune responses against mesothelioma cell lines were seen in seven of the eight subjects evaluated. No clinical responses were seen in the four subjects with advanced disease. However, evidence of disease stability or tumor regression was seen in the remaining five patients, including one dramatic example of partial tumor regression at sites not in contiguity with vector infusion. These data show that Ad.IFN-α2b has potential therapeutic benefit in MPM and that it generates anti-tumor immune responses that may induce anatomic and/or metabolic reductions in distant tumor.
Clinical trial registered with (NCT 01212367).
PMCID: PMC3262033  PMID: 21642245
clinical trials; immunotherapy; gene therapy
Clinics in chest medicine  2011;32(4):865-885.
Both advanced stage lung cancer and malignant pleural mesothelioma are associated with a poor prognosis. Although there have been advances in treatment regimens for both diseases, these have had only a modest effect on their progressive course. Gene therapy for thoracic malignancies represents a novel therapeutic approach and has been evaluated in a number of clinical trials over the last two decades. Strategies have included induction of apoptosis, tumor suppressor gene replacement, suicide gene expression, cytokine based therapy, various vaccination approaches, and adoptive transfer of modified immune cells. This review will consider the clinical results, limitations, and future directions of gene therapy trials for thoracic malignancies.
PMCID: PMC3210443  PMID: 22054892
Gene Therapy; Immunotherapy; Lung cancer; Mesothelioma
6.  Pharmacologic Activation of the Innate Immune System to Prevent Respiratory Viral Infections 
Drugs that can rapidly inhibit respiratory infection from influenza or other respiratory pathogens are needed. One approach is to engage primary innate immune defenses against viral infection, such as activating the IFN pathway. In this study, we report that a small, cell-permeable compound called 5,6-di-methylxanthenone-4-acetic acid (DMXAA) can induce protection against vesicular stomatitis virus in vitro and H1N1 influenza A virus in vitro and in vivo through innate immune activation. Using the mouse C10 bronchial epithelial cell line and primary cultures of nasal epithelial cells, we demonstrate DMXAA activates the IFN regulatory factor-3 pathway leading to production of IFN-β and subsequent high-level induction of IFN-β–dependent proteins, such as myxovirus resistance 1 (Mx1) and 2′,5′-oligoadenylate synthetase 1 (OAS1). Mice treated with DMXAA intranasally elevate mRNA/protein expression of Mx1 and OAS1 in the nasal mucosa, trachea, and lung. When challenged intranasally with a lethal dose of H1N1 influenza A virus, DMXAA reduced viral titers in the lungs and protected 80% of mice from death, even when given at 24 hours before infection. These data show that agents, like DMXAA, that can directly activate innate immune pathways, such as the IFN regulatory factor-3/IFN-β system, in respiratory epithelial cells can be used to protect from influenza pneumonia and potentially in other respiratory viral infections. Development of this approach in humans could be valuable for protecting health care professionals and “first responders” in the early stages of viral pandemics or bioterror attacks.
PMCID: PMC3265219  PMID: 21148741
innate immunity; interferon; influenza; pneumonia; bronchial epithelium
7.  Multiple injections of electroporated autologous T cells expressing a chimeric antigen receptor mediate regression of human disseminated tumor 
Cancer research  2010;70(22):9053-9061.
Redirecting T lymphocyte antigen specificity by gene transfer can provide large numbers of tumor reactive T lymphocytes for adoptive immunotherapy. However, safety concerns associated with viral vector production have limited clinical application of T cells expressing chimeric antigen receptors (CARs). T lymphocytes can be gene modified by RNA electroporation without integration-associated safety concerns. To establish a safe platform for adoptive immunotherapy, we first optimized the vector backbone for RNA in vitro transcription to achieve high level transgene expression. CAR expression and function of RNA-electroporated T cells could be detected up to a week post electroporation. Multiple injections of RNA CAR electroporated T cells mediated regression of large vascularized flank mesothelioma tumors in NOD/scid/γc(−/−) mice. Dramatic tumor reduction also occurred when the pre-existing intraperitoneal human-derived tumors, that had been growing in vivo for over 50 days, were treated by multiple injections of autologous human T cells electroporated with anti-mesothelin CAR mRNA. This is the first report using matched patient tumor and lymphocytes demonstrating that autologous T cells from cancer patients can be engineered to provide an effective therapy for a disseminated tumor in a robust preclinical model. Multiple injections of RNA engineered T cells are a novel approach for adoptive cell transfer, providing flexible platform for the treatment of cancer that may complement the use of retroviral and lentiviral engineered T cells. This approach may increase the therapeutic index of T cells engineered to express powerful activation domains without the associated safety concerns of integrating viral vectors.
PMCID: PMC2982929  PMID: 20926399
adoptive transfer; chimeric antigen receptor; electroporation; tumor immunotherapy; mesothelioma

Results 1-7 (7)