Optimising Translational Research Opportunities: A Systematic Review and Narrative Synthesis of Basic and Clinician Scientists' Perspectives of Factors Which Enable or Hinder Translational Research

Introduction

Translational research is central to international health policy, research and funding initiatives. Despite increasing use of the term, the translation of basic science discoveries into clinical practice is not straightforward. This systematic search and narrative synthesis aimed to examine factors enabling or hindering translational research from the perspective of basic and clinician scientists, a key stakeholder group in translational research, and to draw policy-relevant implications for organisations seeking to optimise translational research opportunities.

Methods and Results

We searched SCOPUS and Web of Science from inception until April 2015 for papers reporting scientists’ views of the factors they perceive as enabling or hindering the conduct of translational research. We screened 8,295 papers from electronic database searches and 20 papers from hand searches and citation tracking, identifying 26 studies of qualitative, quantitative or mixed method designs. We used a narrative synthesis approach and identified the following themes: 1) differing concepts of translational research 2) research processes as a barrier to translational research; 3) perceived cultural divide between research and clinical care; 4) interdisciplinary collaboration as enabling translation research, but dependent on the quality of prior and current social relationships; 5) translational research as entrepreneurial science. Across all five themes, factors enabling or hindering translational research were largely shaped by wider social, organisational, and structural factors.

Conclusion

To optimise translational research, policy could consider refining translational research models to better reflect scientists’ experiences, fostering greater collaboration and buy in from all types of scientists. Organisations could foster cultural change, ensuring that organisational practices and systems keep pace with the change in knowledge production brought about by the translational research agenda.

Abstract 2315: Dynamic SPECT imaging of PSMA-specific CAR T cells in mice bearing prostate cancer

Immunotherapy using CAR-T-cells is acquiring an expanding role in the treatment of malignant disease. However, efficacy of solid tumour CAR-T-immunotherapy has proven inconsistent. Limitations include poor T-cell trafficking to tumour deposits, insufficient T-cell longevity in-vivo and the occurrence of both predicted and unanticipated on-target and off-target toxicity. To refine this therapeutic approach, it is desirable to develop systems that allow the monitoring of T-cell location and persistence in-vivo.

A retroviral vector named PiN-4 was constructed, which co-expresses: (i) an interleukin (IL)-4-responsive chimeric cytokine receptor (4αβ); (ii) a prostate-specific membrane antigen (PSMA)-targeted CAR (P28z) and (iii) hNIS, which promotes the uptake of technetium-99m pertechnetate (99mTcO4−) in viable cells. IL-4 enriched human 4P28zN+ T-cells were administered intravenously to Nod Scid Gamma (NSG) mice bearing prostate tumour xenografts.

Measurement of the tumour xenografts by bioluminescent imaging (BLI) found that only PSMA-expressing tumours responded to 4P28zN+ T-cell treatment. Longitudinal SPECT-CT imaging further confirmed this with the preferential accumulation of 4P28zN+ T-cells in PSMA-expressing tumours compared to PSMA-negative tumours.

Use of NIS as a T-cell imaging reporter brings several potential advantages. It promotes receptor-mediated uptake of the inexpensive, low toxicity and clinically useful SPECT tracer, technetium-99m pertechnetate (99mTcO4−). In addition, the ectopic expression of NIS is well tolerated by host cells and hNIS functions only in viable cells. These data demonstrate proof of concept for the utility of hNIS as an imaging reporter in genetically engineered T-cells.

Citation Format: Nia Emami-Shahri, Julie Foster, Jane Sosabowski, John Maher, Sophie Papa. Dynamic SPECT imaging of PSMA-specific CAR T cells in mice bearing prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2315.

Role of the colony-stimulating factor (CSF)/CSF-1 receptor axis in cancer

Cancer cells employ a variety of mechanisms to evade apoptosis and senescence. Pre-eminent among these is the aberrant co-expression of growth factors and their ligands, forming an autocrine growth loop that promotes tumour formation and progression. One growth loop whose transforming potential has been repeatedly demonstrated is the CSF-1/CSF-1R axis. Expression of CSF-1 and/or CSF-1R has been documented in a number of human malignancies, including breast, prostate and ovarian cancer and classical Hodgkin's lymphoma (cHL). This review summarizes the large body of work undertaken to study the role of this cytokine receptor system in malignant transformation. These studies have attributed a key role to the CSF-1/CSF-1R axis in supporting tumour cell survival, proliferation and enhanced motility. Moreover, increasing evidence implicates paracrine interactions between CSF-1 and its receptor in defining a tumour-permissive and immunosuppressive tumour-associated stroma. Against this background, we briefly consider the prospects for therapeutic targeting of this system in malignant disease.

Sexual interactions with unfamiliar females reduce hippocampal neurogenesis among adult male rats

Recent experiments have shown that sexual interactions prior to cell proliferation cause an increase in neurogenesis in adult male rats. Because adult neurogenesis is critical for some forms of memory, we hypothesized that sexually induced changes in neurogenesis may be involved in mate recognition. Sexually naive adult male rats were either exposed repeatedly to the same sexual partner (familiar group) or to a series of novel sexual partners (unfamiliar group), while control males never engaged in sexual interactions. Ovariectomized female rats were induced into estrus every four days. Males were given two injections of 5-bromo-2'-deoxyuridine (BrdU) (200mg/kg) to label proliferating cells, and the first sexual interactions occurred three days later. Males in the familiar and unfamiliar groups engaged in four, 30-min sexual interactions at four-day intervals, and brain tissue was collected the day after the last sexual interaction. Immunohistochemistry followed by microscopy was used to quantify BrdU-labeled cells. Sexual interactions with unfamiliar females caused a significant reduction in neurogenesis in the dentate gyrus compared to males that interacted with familiar females and compared to the control group. The familiar group showed no difference in neurogenesis compared to the control group. Males in the familiar group engaged in significantly more sexual behavior (ejaculations and intromissions) than did males in the unfamiliar group, suggesting that level of sexual activity may influence neurogenesis levels. In a second experiment, we tested whether this effect was unique to sexual interactions by replicating the entire procedure using anestrus females. We found that interactions with unfamiliar anestrus females reduced neurogenesis relative to the other groups, but this effect was not statistically significant. In combination, these results indicate that interactions with unfamiliar females reduce adult neurogenesis and the effect is stronger for sexual interactions than for social interactions.

Abstract B129: Chimeric antigen receptor T-cells targeting the αvβ6 integrin demonstrate potent antitumor activity in multiple solid tumors

Chimeric antigen receptors (CARs) are bespoke fusion molecules that couple the binding of a tumor-associated cell surface target to the delivery of a tailored T-cell activating signal. CAR T-cells targeting CD19 have demonstrated unprecedented efficacy in the treatment of patients with refractory B-cell malignancy although solid tumors present several additional hurdles to the development of CAR T-cell immunotherapy. One such hurdle is identifying suitable target antigens to maximise tumor targeting and minimise toxicity to healthy tissue. A highly promising candidate is the epithelial-specific integrin, αvβ6. Here, we demonstrate that CAR T-cells targeting αvβ6 have potent anti-tumor activity across a wide range of solid malignancies in pre-clinical models.

The αvβ6 integrin is over-expressed in solid tumors derived from pancreas, head and neck, skin, uterine cervix, lung, colon, breast and fallopian tube/ovary and is generally associated with worsened prognosis. It exerts several pro-tumorigenic activities including activation of TGF-β1, epithelial to mesenchymal transition, cellular migration and matrix metalloproteinase activity. By contrast, αvβ6 is minimally expressed in normal tissue and expression is largely restricted to wound healing.

We have evaluated two peptide-targeting moieties to direct specificity of an αvβ6-specific CD28+CD3ζ-based second generation CAR (A20-28z). We show that a 20mer peptide derived from viral protein 1 of foot and mouth disease virus achieves highly effective targeting. This 20mer peptide (termed A20) contains two αvβ6-binding motifs (RGD and DLXXL) and binds with >1000-fold more specificity to this integrin than other family members such as αvβ3, αvβ5 and α5β1. To evaluate anti-tumor activity we compared A20-28z with two control CAR constructs. An αvβ6 non-binding peptide was generated in which the RGDL motif within A20FMDV2 was substituted with AAAA (termed C20) and a non-signaling CAR constructed whereby A20 was fused to a truncated CD28 endodomain (termed A20-Tr).

A20-28z T-cells destroy and undergo activation by a range of pancreatic, breast and ovarian tumor cell lines in-vitro. By contrast, cells that express low but detectable levels of this integrin are ignored. To expand CAR T-cells preferentially during ex-vivo culture, an IL-4-responsive fusion gene (4βα) was co-expressed which delivers a potent and selective mitogenic signal only to the genetically modified T-cells. In-vivo efficacy of αvβ6 re-targeted human CAR T-cells was demonstrated in SCID Beige mice bearing established Panc04.03 pancreatic and SKOV-3 ovarian tumor xenografts, that express high and intermediate levels of αvβ6 respectively. Ovarian tumor response was significant, but was ultimately limited by transient in-vivo CAR T-cell expansion followed by progressive loss thereafter. In contrast, pancreatic tumours with high αvβ6 expression demonstrated significant tumor regression in response to A20-28z T-cells and exhibited durable responses.

Although the CAR targeting moiety engages murine αvβ6, minimal toxicity was observed in these mouse models, which can fully recapitulate lethal cytokine release syndrome in response to human CAR T-cells. Taken together, these data provide strong support for the clinical evaluation of αvβ6 re-targeted CAR T-cell immunotherapy in solid tumors that express this integrin.

Citation Format: Lynsey May Whilding, Ana C. Parente-Pereira, Tomasz Zabinski, David M. Davies, Roseanna Petrovic, Shelia Violette, Sadaf Ghaem-Maghami, Sabari Vallath, John Marshall, John Maher. Chimeric antigen receptor T-cells targeting the αvβ6 integrin demonstrate potent antitumor activity in multiple solid tumors. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B129.

Abstract A075: Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells

Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumour commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease.

Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA- independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene-transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy.

Methods: Three second-generation cMet-targeted CARs (containing a fused CD28/CD3ζ endodomain) have been developed, distinguished by peptide-binding motifs. Functionality of MET-re targeted T-cells has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels.

Results: Studies to date have shown that human T-cells engineered to express cMet CARs can destroy mesothelioma tumour cell monolayers, accompanied by T-cell proliferation and cytokine production. To further potentiate the activity of the cMet targeted CARs, a dual targeting approach to both cMet and the ErbB family is currently under evaluation. The second advantage of this approach is in diminishing the potential toxicity risks associate with “on target, off tumour” toxicity. An MPM xenograft model has been established utilising bioluminescence to further evaluate functionality and toxicity in vivo.

Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy cMet-expressing MPM tumour cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach.

Citation Format: Thivyan Thayaparan, Sjoukje J.C. van der Stegen, Ana C. Parente Pereira Puri, Roseanna Maria Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A075.

Abstract B124: Immunotherapy of acute myeloid leukemia using Vg9Vd2 T-cells

Disease remission is successfully induced in the majority of patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), but is generally not sustained without stem cell transplantation. Adoptive immunotherapy offers an attractive option to consolidate AML remission. Here, we hypothesized that ex-vivo expanded Vg9Vd2 T-cells will mediate a therapeutically beneficial graft versus leukemia (GvL) effect in this disease.

Peripheral blood mononuclear cells from healthy donors and from patients with AML were activated in-vitro using zoledronic acid and a cytokine cocktail, containing IL-2. As a result, we observed an average 200-fold expansion of Vg9Vd2 T-cells from AML patients, over 15 days. Such expansion was only observed in patients without circulating AML blasts. Expanded patient-derived Vg9Vd2 T-cells exhibited a less differentiated phenotype than cells from healthy donors, indicated by higher expression of CD62L, CCR7 and CD27. A four hour Annexin V cytotoxicity assay using KG-1 and U937 leukemic cells showed that these Vg9Vd2 T-cells were cytotoxic and produced nanogram amounts of interferon-g; (IFN-g).

In a parallel approach, we investigated feasibility of developing a universal allogeneic Vg9Vd2 T-cell therapy. Feasibility of this approach has been demonstrated in a small trial in which haploidentical donor-derived Vg9Vd2 T-cells were safely infused and achieved an efficacy signal in patients with advanced haematological diseases. We have recently developed a novel method to expand Vg9Vd2 T-cells from healthy donors ex-vivo (“Method 2 (M2)” cells – patent protected), which improves their expansion over 2 weeks to 1700 fold. Cytotoxicity data shows that M2 cells destroy luciferase-expressing U937 and KG-1 target cells at 2-3 fold enhanced efficiency, accompanied by 2-3.5-fold increased IFN-g; release when compared to cells expanded using conventional approaches. Furthermore, M2 cells can achieve serial killing of AML cell lines through up to 4 cycles of re-stimulation. Treatment of SCID-Beige mice with an established U937 leukemic burden is also more effective using M2 expanded Vg9Vd2 T-cells, particularly when combined with zoledronic acid. Together these data highlight the promise of Vg9Vd2 T-cell immunotherapy of AML.

Citation Format: Ana C. Parente-Pereira, Lynsey M. Whilding, Pramila Krishnamurthy, Richard Beatson, Tomasz Zabinski, Linda Barber, Farzin Farzaneh, Ghulam Mufti, John Maher. Immunotherapy of acute myeloid leukemia using Vg9Vd2 T-cells. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B124.

CAR T-cell immunotherapy: The path from the by-road to the freeway?

Chimeric antigen receptors are genetically encoded artificial fusion molecules that can re-program the specificity of peripheral blood polyclonal T-cells against a selected cell surface target. Unparallelled clinical efficacy has recently been demonstrated using this approach to treat patients with refractory B-cell malignancy. However, the approach is technically challenging and can elicit severe toxicity in patients. Moreover, solid tumours have largely proven refractory to this approach. In this review, we describe the important structural features of CARs and how this may influence function. Emerging clinical experience is summarized in both solid tumours and haematological malignancies. Finally, we consider the particular challenges imposed by solid tumours to the successful development of CAR T-cell immunotherapy, together with a number of innovative strategies that have been developed in an effort to reverse the balance in favour of therapeutic benefit.

Chimeric antigen receptors: On the road to realising their full potential

Chimeric antigen receptors (CARs) are fusion molecules that may be genetically delivered ex-vivo to T-cells and other immune cell populations, thereby conferring specificity for native target antigens found on the surface of tumour and other target cell types. Antigen recognition by CARs is neither restricted by nor dependent upon human leukocyte antigen antigen expression, favouring widespread use of this technology across transplantation barriers. Signalling is delivered by a designer endodomain that provides a tailored and target-dependent activation signal to polyclonal circulating T-cells. Recent clinical data emphasise the enormous promise of this emerging immunotherapeutic strategy for B-cell malignancy, notably acute lymphoblastic leukaemia. In that context, CARs are generally targeted against the ubiquitous B-cell antigen, CD19. However, CAR T-cell immunotherapy is limited by potential for severe on-target toxicity, notably due to cytokine release syndrome. Furthermore, efficacy in the context of solid tumours remains unproven, owing in part to lack of availability of safe tumour-specific targets, inadequate CAR T-cell homing and hostility of the tumour microenvironment to immune effector deployment. Manufacture and commercial development of this strategy also impose new challenges not encountered with more traditional drug products. Finally, there is increasing interest in the application of this technology to the treatment of non-malignant disease states, such as autoimmunity, chronic infection and in the suppression of allograft rejection. Here, we consider the background and direction of travel of this emerging and highly promising treatment for malignant and other disease types.

Abstract 3144: Development of immunotherapy for anaplastic large cell lymphoma (ALCL) using CSF1R retargeted human T lymphocytes

Anaplastic large cell lymphoma (ALCL), a type of T/null-cell lymphoma, represents about 20-30% of paediatric lymphomas and has an aggressive clinical course with frequent relapse. Recently, high-level expression of CSF1R on malignant cells in ALCL has been linked to shorter progression free survival, providing a rationale to test adoptive C28ζ-mediated T-cell therapy. This approach encompasses the genetic modification of T-cells to express a chimeric antigen receptor (CAR) named C28ζ, a fusion receptor coupling the recognition of CSF1R on the tumour cell surface to the delivery of tailored T-cell activation signal provided by a fused CD28+CD3ζ endodomain. To optimize this approach for human translation, the C28ζ CAR was co-expressed with the chimeric cytokine receptor 4αβ (combination termed “C4”), which allows for selective expansion and enrichment of CAR-transduced T-cells using IL-4. PBMCs of healthy donors were isolated and activated using anti-CD3/CD28 beads. Following retroviral T-cell transduction and 14 days expansion of C4+ T-cells in the presence of IL-4, co-cultures with a panel of ALCL cell lines (2 ALK positive and 2 ALK negative ALCL cell lines) were set up to test C4 efficacy in vitro. Successful re-targeting of C4+ T-cells was confirmed by monitoring target cell destruction. Conditioned media was collected and analysed for IFN-γ and IL-2 production. Cytotoxicity, cytokine release and T-cell proliferation data demonstrated Ag-specific activation of the C4+ cells, which contrasted with T-cells expressing a control CAR with truncated endodomain. This data provides for the first time the basis for successful application of CAR-based immunotherapy against CSF1R-expressing malignancies.

Citation Format: Daniela Achkova, James Spicer, John Maher. Development of immunotherapy for anaplastic large cell lymphoma (ALCL) using CSF1R retargeted human T lymphocytes. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3144. doi:10.1158/1538-7445.AM2015-3144

Evaluation of miR-122 as a Serum Biomarker for Hepatotoxicity in Investigative Rat Toxicology Studies

MicroRNAs are short noncoding RNAs involved in regulation of gene expression. Certain microRNAs, including miR-122, seem to have ideal properties as biomarkers due to good stability, high tissue specificity, and ease of detection across multiple species. Recent reports have indicated that miR-122 is a highly liver-specific marker detectable in serum after liver injury. The purpose of the current study was to assess the performance of miR-122 as a serum biomarker for hepatotoxicity in short-term (5–28 days) repeat-dose rat toxicology studies when benchmarked against routine clinical chemistry and histopathology. A total of 23 studies with multiple dose levels of experimental compounds were examined, and they included animals with or without liver injury and with various hepatic histopathologic changes. Serum miR-122 levels were quantified by reverse transcription quantitative polymerase chain reaction. Increases in circulating miR-122 levels highly correlated with serum elevations of liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH). Statistical analysis showed that miR-122 outperformed ALT as a biomarker for histopathologically confirmed liver toxicity and was equivalent in performance to AST and GLDH. Additionally, an increase of 4% in predictive accuracy was obtained using a multiparameter approach incorporating miR-122 with ALT, AST, and GLDH. In conclusion, serum miR-122 levels can be utilized as a biomarker of hepatotoxicity in acute and subacute rat toxicology studies, and its performance can rival or exceed those of standard enzyme biomarkers such as the liver transaminases.

Ovarian cancer immunotherapy using PD-L1 siRNA targeted delivery from folic acid-functionalized polyethylenimine: strategies to enhance T cell killing

Adoptive T cell immunotherapy is a promising treatment strategy for epithelial ovarian cancer (EOC). However, programmed death ligand-1 (PD-L1), highly expressed on EOC cells, interacts with programmed death-1 (PD-1), expressed on T cells, causing immunosuppression. This study aims to block PD-1/PD-L1 interactions by delivering PD-L1 siRNA, using various folic acid (FA)-functionalized polyethylenimine (PEI) polymers, to SKOV-3-Luc EOC cells, and investigate the sensitization of the EOC cells to T cell killing. To enhance siRNA uptake into EOC cells, which over express folate receptors, PEI is modified with FA or PEG-FA so that siRNA is complexed into nanoparticles with folate molecules on the surface. PEI modification with a single functional group lowers the polymer cytotoxicity compared to unmodified PEI. FA-conjugated polymers increase siRNA uptake into SKOV-3-luc cells and decrease unspecific uptake into monocytes. All polymers result in 40% to 50% PD-L1 protein knockdown. Importantly, SKOV-3-Luc cells treated with either PEI-FA or PEI- polyethylene glycol (PEG)-FA/PD-L1 siRNA complexes are up to twofold more sensitive to T cell killing compared to scrambled siRNA treated controls. These findings are the first to demonstrate that PD-L1 knockdown in EOC cells, via siRNA/FA-targeted delivery, are able to sensitize cancer cells to T cell killing.

Adoptive T-cell therapy for cancer in the United kingdom: a review of activity for the British Society of Gene and Cell Therapy annual meeting 2015

Adoptive T-cell therapy is delivering objective clinical responses across a number of cancer indications in the early phase clinical setting. Much of this clinical activity is taking place at major clinical academic centers across the United States. This review focuses upon cancer-focused cell therapy activity within the United Kingdom as a contribution to the 2015 British Society of Gene and Cell Therapy annual general meeting. This overview reflects the diversity and expansion of clinical and preclinical studies within the United Kingdom while considering the background context of this work against new infrastructural developments and the requirements of nationalized healthcare delivery within the UK National Health Service.

Using routinely collected data to stratify prostate cancer patients into phases of care in the United Kingdom: implications for resource allocation and the cancer survivorship programme

BACKGROUND

Prostate cancer is the most commonly diagnosed malignancy in British men. The increasing use of PSA screening test has resulted in many more patients being diagnosed with this condition. Advances in its treatment have improved the survival rate among these patients. By 2040, the prevalence of prostate cancer survivors is expected to reach 830 000. Many of them will require medical support for the management of their progressive disease or long-term toxicities from previous treatments. Successful implementation of the cancer survivorship programme among these patients depends on a good understanding of their demand on the health care system. The aim of this study is to segment the population of prostate cancer survivors into different needs groups and to quantify them with respect to their phase of care.

METHODS

Incidence, survival, prevalence and mortality data collected and reported by cancer registries across the United Kingdom have been used for the current study to provide indicative estimates as to the number of prostate cancer patients in each phase of the care pathway in a year.

RESULTS

The majority of prostate cancer patients are in the post-treatment monitoring phase. Around a fifth of the patients are either receiving treatment or in the recovery and readjustment phase having completed their treatment in the preceding year. Thirteen percent have not received any anticancer treatment, a further 12% (32 000) have developed metastatic disease and 4% are in the final stage of their lives.

CONCLUSION

On the basis of our estimates, patients undergoing post-treatment monitoring phase will constitute the biggest group among prostate cancer survivors. The pressure to provide adequate follow-up care to these patients will be a challenge. There is limited data available to definitively quantify the number of prostate cancer patients who follow different pathways of care, and we hope this study has highlighted the importance of collecting and reporting of such data to help future health care planning for these patients.

Smooth muscle relaxation and activation of the large conductance Ca(++)-activated K+ (BK(Ca)) channel by novel oestrogens

BACKGROUND AND PURPOSE

Oestrogens can interact directly with membrane receptors and channels and can activate vascular BK(Ca) channels. We hypothesized that novel oestrogen derivatives could relax smooth muscle by an extracllular effect on the α and β1 subunits of the BK(Ca) channel, rather than at an intracellular site.

EXPERIMENTAL APPROACH

We studied the effects of novel oestrogens on the tension of pre-contracted isolated rat aortic rings, and on the electrophysiological properties of HEK 293 cells expressing the hSloα or hSloα+β1 subunits. Two of the derivatives incorporated a quaternary ammonium side-chain making them membrane impermeable.

KEY RESULTS

Oestrone, oestrone oxime and Quat DME-oestradiol relaxed pre-contracted rat aorta, but only Quat DME-oestradiol-induced relaxation was iberiotoxin sensitive. However, only potassium currents recorded in HEK 293 cells over-expressing both hSloα and hSloβ1 were activated by oestrone, oestrone oxime and Quat DME-oestradiol.

CONCLUSION AND IMPLICATIONS

The novel oestrogens were able to relax smooth muscle, but through different mechanisms. In particular, oestrone oxime required the presence of the endothelium to exert much of its effect, whilst Quat DME-oestradiol depended both on NO and BK(Ca) channel activation. The activation of BK(Ca) currents in HEK 293 cells expressing hSloα+β1 by Quat DME-oestradiol is consistent with an extracellular binding site between the two subunits. The binding site resides between the extracellular N terminal of the α subunit and the extracellular loop between TM1 and 2 of the β1 subunit. Membrane-impermeant Quat DME-oestradiol lacks an exchangeable hydrogen on the A ring obviating antioxidant activity.

ErbB-targeted CAR T-cell immunotherapy of cancer

Chimeric antigen receptor (CAR) based immunotherapy has been under development for the last 25 years and is now a promising new treatment modality in the field of cancer immunotherapy. The approach involves genetically engineering T cells to target malignant cells through expression of a bespoke fusion receptor that couples an HLA-independent antigen recognition domain to one or more intracellular T-cell activating modules. Multiple clinical trials are now underway in several centers to investigate CAR T-cell immunotherapy of diverse hematologic and solid tumor types. The most successful results have been achieved in the treatment of patients with B-cell malignancies, in whom several complete and durable responses have been achieved. This review focuses on the preclinical and clinical development of CAR T-cell immunotherapy of solid cancers, targeted against members of the ErbB family.

Adoptive Immunotherapy of Epithelial Ovarian Cancer with Vγ9Vδ2 T Cells, Potentiated by Liposomal Alendronic Acid

Adoptive immunotherapy using γδ T cells harnesses their natural role in tumor immunosurveillance. The efficacy of this approach is enhanced by aminobisphosphonates such as zoledronic acid and alendronic acid, both of which promote the accumulation of stimulatory phosphoantigens in target cells. However, the inefficient and nonselective uptake of these agents by tumor cells compromises the effective clinical exploitation of this principle. To overcome this, we have encapsulated aminobisphosphonates within liposomes. Expanded Vγ9Vδ2 T cells from patients and healthy donors displayed similar phenotype and destroyed autologous and immortalized ovarian tumor cells, following earlier pulsing with either free or liposome-encapsulated aminobisphosphonates. However, liposomal zoledronic acid proved highly toxic to SCID Beige mice. By contrast, the maximum tolerated dose of liposomal alendronic acid was 150-fold higher, rendering it much more suited to in vivo use. When injected into the peritoneal cavity, free and liposomal alendronic acid were both highly effective as sensitizing agents, enabling infused γδ T cells to promote the regression of established ovarian tumors by over one order of magnitude. Importantly however, liposomal alendronic acid proved markedly superior compared with free drug following i.v. delivery, exploiting the “enhanced permeability and retention effect” to render advanced tumors susceptible to γδ T cell–mediated shrinkage. Although folate targeting of liposomes enhanced the sensitization of folate receptor–α+ ovarian tumor cells in vitro, this did not confer further therapeutic advantage in vivo. These findings support the development of an immunotherapeutic approach for ovarian and other tumors in which adoptively infused γδ T cells are targeted using liposomal alendronic acid.

How should a district general hospital immunology service screen for anti-nuclear antibodies? An 'in-the-field' audit

Anti-nuclear antibody (ANA) testing assists in the diagnosis of several immune-mediated disorders. The gold standard method for detection of these antibodies is by indirect immunofluorescence testing on human epidermoid laryngeal carcinoma (HEp-2) cells. However, many laboratories test for these antibodies using solid-phase assays such as enzyme-linked immunosorbent assay (ELISA), which allows for higher throughput testing at reduced cost. In this study, we have audited the performance of a previously established ELISA assay to screen for ANA, making comparison with the gold standard HEp-2 immunofluorescence test. A prospective and unselected sample of 89 consecutive ANA test requests by consultant rheumatologists were evaluated in parallel over a period of 10 months using both tests. ELISA and HEp-2 screening assays yielded 40 (45%) and 72 (81%) positive test results, respectively, demonstrating lack of concordance between test methods. Using standard and clinical samples, it was demonstrated that the ELISA method did not detect several ANA with nucleolar, homogeneous and speckled immunofluorescence patterns. None of these ELISA(NEG) HEp-2(POS) ANA were reactive with a panel of six extractable nuclear antigens or with double-stranded DNA. Nonetheless, 13 of these samples (15%) originated from patients with recognized ANA-associated disease (n = 7) or Raynaud's phenomenon (n = 6). We conclude that ELISA screening may fail to detect clinically relevant ANA that lack defined specificity for antigen.

Abstract 2800: Immunotherapy of malignant pleural mesothelioma using MET specific t – cells

Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumor commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease.

Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA-independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy.

Methods: Three MET-targeted peptide-binding motifs have been incorporated into a second generation CAR framework containing a fused CD28/CD3ζ endodomain. Functional assessment of MET-targeted CARs has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels.

Results: In preliminary studies we have shown that human T-cells engineered to express MET CARs can destroy mesothelioma tumor cell monolayers, accompanied by T-cell proliferation and cytokine production. Xenograft models are currently under development using bioluminescence to further evaluate functionality and toxicity in vivo.

Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy MET-expressing MPM tumor cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach.

Citation Format: Thivyan Thayaparan, Sjoukje v.d Stegen, Ana C. Parente Pereira, Roseanna Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using MET specific t – cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2800. doi:10.1158/1538-7445.AM2014-2800