Cancer immunotherapy is revolutionizing the treatment of many cancers. This revolution is being led by drugs that enhance the immune system’s T cell’s ability to kill cancer cells. This includes drugs such as Keytruda, an antibody that blocks a molecule called PD1 on T cells, and Kymriah, a living drug which is a product of using gene therapy to engineer a patient’s own T cells to better attack their cancer cells. Despite the amazing successes in some patients, unfortunately, not all patients respond to current immunotherapies.  

One of the cell types that appears to be responsible for the failure is a cell type called a macrophage. Macrophages are part of the immune system and have a function in protecting us from infections. However, tumors can reprogram macrophages to suppress other cells of the immune system, which benefits the tumor by preventing killer immune cells from entering the tumor and killing the cancer cells. Considerable evidence indicates that eliminating the macrophages of a tumor could improve patient outcomes and response to treatments, but traditional pharmacological approaches for doing this have not shown clinical benefit.  

To overcome the limitations of traditional drugs, we will harness the power of gene therapy and develop a new type of living drug in which we would gene engineer a patient’s own T cells to kill the immune suppressing macrophages in their tumors. This would eliminate a major barrier to immunotherapy treatment and help the patient’s immune system to eliminate cancer cells. This novel strategy will draw on the considerable advances in the gene therapy field that led to the development of Kymriah, and other drugs based on the use of chimeric antigen receptor (CAR).  

We will develop a CAR that specifically kills macrophages in a tumor, while sparing macrophages in healthy tissue. We will test our strategy in preclinical animal models of lung and breast cancer to determine if our tumor macrophage killing CAR can lead to the elimination of aggressive tumors. We will also evaluate further refinements to the therapy to make these CAR even more potent at helping the immune system permanently eliminate different cancer. This project will lead to the development of a new gene and cell immunotherapy with the potential to treat a wide variety of cancers and help a patient’s own immune system end their cancer. 

This Alliance for Cancer Gene Therapy Research Fellow is funded in part by Swim Across America. 

Few procedures are available for physicians to rapidly and reliably harness immune responses to fight cancer. For example, bioinformatics tools can predict cancer proteins that T cells could react with, but vaccines developed from them commonly fail because the immunized patients do not have enough T cells that are inherently able to recognize the predicted antigens.  

The goal of our research is to develop injectable nanoreagents that can genetically program T cell receptors (TCRs) into circulating lymphocytes, enabling them to recognize cancer proteins. Specifically, we hypothesize that customized cancer-targeting can be introduced into immune cells by combining anti-cancer vaccines with techniques that induce endogenous CD8 T cells to express TCRs specific for the vaccines, and consequently provide them with the ability to react with cancer cells. We further hypothesize that this platform can be used to program helper cells with defined “MHC class-II-restricted TCRs”, and thereby improve responses to tumor antigens compared to conventional immunization methods.  

Our multidisciplinary team of immunologists, bioengineers and geneticists has already established that injected nanoparticles can deliver engineered TCR genes into host T cells in a way that, once they are stimulated by vaccines, the lymphocytes recognize cancer antigens. Following rapid vaccine-induced expansion, these programmed cells continue to differentiate into long-lived memory T lymphocytes.  

We propose to develop a suite of nanoparticle reagents that can rapidly establish anti-cancer immunity by programming in situ specific receptors into the patient’s T cell pool. To achieve this, we will pursue the following Specific Aims:  

(1) to improve our efficiency for introducing vaccine specificity into circulating CD8+ T cells; (2) to establish that this approach boosts immune responses; and (3) to determine if our methods promote the regression of cancer regardless of the patient’s pre-existing TCR landscape.  

To assure the medical relevance of our findings, we will (i) program the lymphocytes to express an affinity-optimized receptor specific for the tumor antigen mesothelin, and (ii) use them to treat a genetically engineered mouse model that faithfully recapitulates human pancreatic ductal adenocarcinoma from inception to invasion. 

 We believe that the data, reagents, and application methods generated by our research will provide the basis for a broad repertoire of gene modification systems that can generate selective immunity against cancer and other diseases.  


Ovarian cancer is the most lethal gynecologic cancer. However, women with evidence of immune cells in their ovarian cancer, specifically T cells, have an improved overall survival. This suggests that T cells control ovarian cancer growth.  

Patient T cells can now be grown to large numbers outside of the body and then reinfused back into the same patient in a process referred to as adoptive T cell therapy. To allow these T cells to “see” the cancer cells, they are engineered outside of the body to express a tumor-sensor called a CAR. Patient T cells genetically engineered to express a CAR can recognize a cancer antigen, such as CD19. Transfer of these anti-CD19 CAR T cells back to terminally diseased patients results in cancer remission in ~90% of treated patients with certain forms of leukemia.  

In order to bring this form of therapy to women with ovarian cancer, we propose to engineer patient T cells to recognize an antigen called folate receptor-alpha, which is expressed by up to 90% of ovarian cancers, and use them to treat women with recurrent ovarian cancer, a disease which kills more than 14,000 women each year, and for which there are no effective treatment options. These CAR T cells can effectively and comprehensibly kill human ovarian cancer cells in mice. The opportunity now exists to provide this form of cancer gene therapy for our patients. Here, we propose conducting a clinical trial to test whether these CAR T cells are safe and effective in women with recurrent ovarian cancer.

Ovarian cancer is one of the deadliest cancers, responsible for the deaths of ~15,000 Americans per year, even more than melanoma, AML or brain tumors. 5-year survival rates have improved little in the last 30 years, and still remain at 30% at best for patients with metastatic ovarian carcinoma, the stage at which most cases are diagnosed. Studies using pre-clinical models indicate that tumor-reactive T cells properly conditioned ex vivo have the capacity to induce significant therapeutic effects against established ovarian cancer, yet the activity of transplanted T cells was suboptimal.  

Novel strategies for reprogramming adoptively transferred anti-tumor T cells, to allow better engraftment and thus superior therapeutic activity in the especially hostile microenvironment of ovarian cancer, are urgently needed. Forkhead box (FOX) proteins are a large family of transcription factors with diverse functions in development, cancer, and aging. Recently we have demonstrated that Foxp1 exerts a novel cell-intrinsic regulation of T cell quiescence.  

In a mouse model of ovarian carcinoma, which recapitulates the microenvironment of solid human ovarian cancers, we find that tumor-associated T cells up-regulate Foxp1 as the tumor progresses. We also find that Foxp1 dampens T cell immune responses. Therefore, in this proposal, we hypothesize that the up-regulation of Foxp1 in ovarian cancer-infiltrating T cells negatively regulates the T cell responses; consequently, Foxp1-deficient tumor-reactive T cells will better resist tumor-induced immunosuppressive signals and elicit superior anti-tumor immunity.  

While we aim to determine the role of Foxp1 in tumor-induced T cell unresponsiveness (Aim 1), we will also use pre-clinical ovarian carcinoma models to determine the therapeutic effectiveness of adoptively transferred T cells lacking Foxp1 (Aim 2). Our initial experiments show that ovarian tumor-bearing mice receiving in vitro-primed anti-tumor T cells deficient in Foxp1 have superior survival over control mice, providing a rationale for novel therapeutic interventions targeting Foxp1 in tumor-reactive T cells from ovarian cancer-bearing women.  

In summary, our proposed work will have a profound effect on the field by defining a novel mechanism for the loss-of-function of anti-tumor T cells in ovarian cancer, which may be applicable to other lethal epithelial tumors. The accomplishment of the work will provide both a mechanistic rationale and proof-of-concept for new interventions aimed at maximizing the effectiveness of adoptively transferred tumor-reactive T cells. Our long-term goal is to develop improved treatment options for ovarian cancer in clinic through adoptive transfer of tumor-reactive T cells, which are genetically modified to overcome tumor-induced immune suppression.

Probably the greatest limitation to the application of gene therapy for the treatment of cancer remains the difficulty in delivering a therapeutic gene efficiently and selectively to its tumor target.  

We have used oncolytic viruses, viruses that have been modified so that they selectively replicate in tumors and not normal tissues, to deliver a variety of genes to tumors. These viruses, based on vaccinia virus can be delivered intravenously into the blood stream, and even though they will then infect many different tissues (including the tumor), the engineered selectivity means they are cleared from all non-tumor tissues. The small amount of virus that does make it to the tumor will rapidly and selectively amplify as the virus replicates and spreads through the tumor. We have also used certain immune cell therapies that are attracted to the tumor, as delivery vehicles to carry the viruses to the tumor, so increasing the amount of virus that gets to the tumor and reducing the amount that goes to other organs.  

We have found that if we express therapeutic genes from these viruses (such as cytokines, that attract the host immune response to help destroy the tumor), we are able to increase their therapeutic benefit. However, because the expression of the cytokines results in destruction of the infected cells, we also reduce the amount of viral replication that occurs. This means that the virus does not get a chance to replicate properly, so reducing its initial delivery and spread within the tumor, and leading to clearance of the virus before it is capable of achieving its own therapeutic potential.  

We have therefore taken an approach that was developed by our collaborators that allows us to control the stability, and so the function, of any protein, and applied this to our oncolytic viral therapies.  

By attaching a small sequence onto any protein, we can flag the protein for rapid destruction by the cell’s degradation pathways. However, if we apply a small molecule that binds to this sequence and shields it, then we stabilize the protein and its function is restored. This allows us to rapidly, reversibly and safely control the levels of functional protein. In this way we can block cytokine function for a period of time (while the virus is cleared from normal cells and amplifies itself to high levels within the tumor; or while the virus is being delivered within an immune cell to the tumor), and so enhance initial delivery and establishment within the tumor. If we then stabilize the cytokine, there is increased production exclusively within the tumor, and so we can safely increase anti-tumor effects.  

We propose to use this system to control the expression of different genes expressed from oncolytic vaccinia viruses, and will use the system to control the virus replication itself. As a result, we can improve the delivery, safety and effectiveness of these (and other) gene therapy approaches, using a system that can be rapidly moved into the clinic. 

Development and delivery of T cells directed against tumor vascular targets offers multiple theoretical advantages: it can be highly specific, efficient and sustained in time. In addition, it has the potential for significant antigen-induced amplification in vivo and is the only one that can provide long-term memory. Active immunization against tumor-derived endothelial cells has produced encouraging preclinical results but is not a practical approach. Furthermore, generation of T cells with native T cell receptor that exhibits high affinity against ‘self’ tumor endothelial antigens is not straightforward. This proposal will test the central hypothesis that T-body cell therapy is the only form of antioangiogenic gene therapy immediately translatable clinically that can deliver sustained VDA-type effect which is tumor-specific, self-amplifying in vivo and endowed with memory. Coupled with the genetic stability of tumor endothelium and the catastrophic consequences that vascular damage has on the tumor, T-body immune-gene therapy could potentially achieve tumor eradication. Presently, we are the only group in the world with the combined expertise to test this hypothesis. In this proposal we will:

(1) Generate and test in vitro human lymphocytes (T cells) engineered to recognize and attack tumor blood vessels. We will engineer lymphocytes to express several molecules that will direct them to tumor blood vessels and we will compare different molecules to identify those that yield optimal efficacy in vitro.

(2) Test engineered lymphocytes (T cells) engineered to recognize and attack tumor blood vessels in vivo. We will use specialized models of mice developed in our laboratory which can be repopulated with human tumor blood vessels. The optimal vector will be selected for clinical development from these in vivo studies. (

3) Conduct a phase I trial to test the safety and anti-tumor efficacy of lymphocytes (T cells) engineered to recognize and attack tumor blood vessels in patients with advanced, recurrent ovarian and peritoneal cancer. Taken together, a translational team of basic scientists and clinicians will provide the first comprehensive evaluation of the use of this redirected T cell concept to implement antiangiogenic immune-gene therapy in cancer patients.

Ovarian cancer is the leading cause of gynecologic cancer death, and though most patients respond to initial chemotherapy, the majority will eventually relapse and die of chemotherapy resistant disease. Despite the advent of newer chemotherapies, the five-year survival for patients with advanced disease remains only 25 percent, and few patients are cured.  

In preliminary studies, we have developed genetically engineered T cells as a complementary immunotherapy to augment traditional treatment strategies. The engineered T cells eradicate large tumors in pre-clinical experiments.  

In this project, we will conduct FDA-mandated pre-clinical experiments, manufacture clinical grade vector, obtain local IRB approval and FDA and NIH/OBA RAC federal approval for the protocol, and then conduct the clinical protocol.  

The protocol will test whether the T cells that are designed to withstand the toxic effects of the tumor are able to mediate tumor regression in patients with advanced ovarian cancer that has failed to regress after chemotherapy.  

Immunotherapy using gene-transduced tumor cells has emerged as a potentially plausible approach for the control of advanced stage ovarian cancer. We have recently demonstrated that vaccination with irradiated murine allogeneic ovarian cancer cells secreting heat shock protein 70 (Hsp70) were capable of generating potent tumor antigen-specific immune responses and strong anti-tumor effects against ovarian cancers (Chang et al. Cancer Research 2007; 67, 10047-10057).  

Hsp70 has been shown to bind antigenic peptides from tumors. The secretion of Hsp70 from the ovarian cancer cells will allow the Hsp70-associated antigenic peptide to be concentrated and targeted to dendritic cells (DCs) with subsequent DC activation. Based on the encouraging preclinical data, we propose to generate a clinical grade tumor cell-based vaccine engineered to secrete high levels of Hsp70. We have access to several high grade serous carcinoma cell lines, that express several known tumor antigens, such as CA-125 and mesothelin.  

The generation of the cGMP clinical lots of a tumor cell-based vaccine using high grade serous carcinoma cell lines that secrete high levels of Hsp70 represents an innovative approach that may create an opportunity for the therapy of these devastating ovarian cancers. This product will form the basis for the development of a pipeline of immunotherapeutic approaches at Johns Hopkins University. Thus, in the current proposal, we propose the following. 

  •  Specific Aim 1: To generate and characterize a high grade serous carcinoma cell line that stably secretes high levels of Hsp70. 
  •  Specific Aim 2: To cGMP manufacture and release Master Cell Banks and a clinical lot, per FDA CBER guidelines, of the Hsp70-secreting ovarian cancer cell-based vaccines.  
  • Specific Aim 3: To perform phase I clinical studies using clinical grade Hsp70-secreting ovarian cancer cell-based vaccines in patients with high grade serous carcinoma.  
  • Specific Aim 4: To characterize tumor antigen-specific CD8+ T cell immune responses in vaccinated individuals.  

Successful implementation of the current proposal may lead to the development of an innovative therapeutic vaccine against high grade ovarian serous carcinoma. We are currently testing two distinct types of cancer vaccines developed at Johns Hopkins, including a mesothelin-expressing Listeria-based vaccine, which is being developed by Anza Therapeutics and the GM-CSF secreting K562 cell line, which is being developed by Cell Genesys.  

The mesothelin-expressing Listeria-based vaccine is currently being tested in patients with pancreatic cancer and mesothelioma, while the GM-CSF secreting K562 cell line is being tested in chronic myeloid leukemia patients. Given the suitable safety of the proposed Hsp70-secreting ovarian cancer cell-based vaccine, we will also examine its application in combination with mesothelin- expressing Listeria and/or GM-CSF secreting K562 cell lines to further enhance the tumor specific immune responses.

Dr. Bartlett has continued his research on the AAV virus in creating vectors for use in gene therapy. His work in developing these vectors provides promising opportunities for the future of ovarian cancer and other cancer treatment as an alternative method of delivering specific genetic information to cancer cells. Dr. Bartlett has also been working on engineering a resistance to the HIV-1 infection through the use of gene therapy.  

He and a team of researchers have developed and studied an anti-HIV lentiviral vector capable of generating cellular resistance to multiple strains of HIV in two different ways. Many animals treated with the vector-modified cells had no detection of the HIV virus in the bloodstream, whereas it was easily detected in the control group not treated with the cells. Dr. Bartlett’s research on vectors is likely to progress the field of gene therapy treatment for both cancer, HIV, and potentially other diseases as well. 

Ovarian cancer is one of the most common and frequently life-threatening malignancies affecting women in the U.S. today: about 25,000 new cases will be diagnosed with the disease this year and over 15,000 women will die from it. Delivering therapeutic genes efficiently and precisely, so that they reach only the targeted cancer cells, is crucial to success. My group has developed a means of delivering therapeutic genes to a specific population of cells in laboratory experiments.  

By rearranging the genetic structure of AAV, a common human virus, we have created a class of molecular Trojan horse viruses, known as vectors, from the Latin “to carry”. These vectors are aimed at ovarian cancer cells via key sequences in the virus shell that allows it to infect only cells in the body displaying a particular marker that is restricted to cancer cells. We are now testing the Trojan horse system’s ability to cure ovarian cancer in laboratory animals. If these studies are successful, this research will help pave the way for clinical trials in women with ovarian cancer and may lead to a new approach to this deadly disease.