Lymphocytic Choriomeningitis Virus Clone 13 Infection Results in CD8 T Cell-Mediated Host Mortality in Diacylglycerol Kinase α-Deficient Mice

Diacylglycerol is a potent element of intracellular secondary signaling cascades whose production is enhanced by cell-surface receptor agonism and function is regulated by enzymatic degradation by diacylglycerol kinases (DGKs). In T cells, stringent regulation of the activity of this second messenger maintains an appropriate balance between effector function and anergy. In this article, we demonstrate that DGKα is an indispensable regulator of TCR-mediated activation of CD8 T cells in lymphocytic choriomeningitis virus Clone 13 viral infection. In the absence of DGKα, Clone 13 infection in a murine model results in a pathologic, proinflammatory state and a multicellular immunopathologic host death that is predominantly driven by CD8 effector T cells.

NK Cell Development and Function in Patients with Fanconi Anemia

Fanconi anemia (FA) is an inherited disorder characterized by diverse congenital malformations, progressive pancytopenia, and predisposition to hematological malignancies and solid tumors. The role of the Fanconi anemia pathway in DNA repair mechanisms and genome instability is well studied. However, the consequences of inherited mutations in genes encoding the FA proteins and the acquired mutations due to impaired DNA repair complex in immune cells are far from understood. Patients with FA show bone marrow failure (BMF) and have a higher risk of developing myelodysplasia (MDS) or acute myeloid leukemia (AML) which are directly related to having chromosomal instability in hematopoietic stem cells and their subsequent progeny. However, immune dysregulation can also be seen in FA. As mature descendants of the common lymphoid progenitor line, NK cells taken from FA patients are dysfunctional in both NK cell-mediated cytotoxicity and cytokine production. The molecular bases for these defects are yet to be determined. However, recent studies have provided directions to define the cause and effect of inherited and acquired mutations in FA patients. Here, we summarize the recent studies in the hematopoietic dysfunction, focusing on the impairment in the development and functions of NK cells in FA patients, and discuss the possible mechanisms and future directions.

Role of GATA2 in Human NK Cell Development

Natural killer (NK) cells are major innate lymphocytes. NK cells do not require prior antigen exposure to mediate antitumor cytotoxicity or proinflammatory cytokine production. Since they use only nonclonotypic receptors, they possess high clinical value in treatment against a broad spectrum of malignancies. Irrespective of this potential, however, the transcriptional regulation that governs human NK cell development remains far from fully defined. Various environmental cues initiate a complex network of transcription factors (TFs) during their early development, one of which is GATA2, a master regulator that drives the commitment of common lymphoid progenitors (CLPs) into immature NK progenitors (NKPs). GATA2 forms a core heptad complex with six other TFs (TAL1, FLI1, RUNX1, LYL1, LMO2, and ERG) to mediate its transcriptional regulation in various cell types. Patients with GATA2 haploinsufficiency specifically lose CD56bright NK cells, with or without a reduced number of CD56dlm NK cells. Here, we review the recent progress in understanding GATA2 and its role in human NK cell development and functions.

Impact of Neoadjuvant Chemoradiation on Pathologic Response in Patients With Localized Pancreatic Cancer

Introduction/Background: Multimodal neoadjuvant therapy has resulted in increased rates of histologic response in pancreatic tumors and adjacent lymph nodes. The biologic significance of the collective response in the primary tumor and lymph nodes is not understood.

Methods: Patients with localized PC who received neoadjuvant therapy and surgery with histologic assessment of the primary tumor and local-regional lymph nodes were included. Histopathologic response was classified using the modified Ryan score as follows: no viable cancer cells (CR), rare groups of cancer cells (nCR), residual cancer with evident tumor regression (PR), and extensive residual cancer with no evident tumor regression (NR). Nodal status was defined by number of lymph nodes (LN) with tumor metastases: N0 (0 LN), N1 (1–3), N2 (≥4).

Results: Of 341 patients with localized PC who received neoadjuvant therapy and surgery, 107 (31%) received chemoradiation alone, 44 (13%) received chemotherapy alone, and 190 (56%) received chemotherapy and chemoradiation. Histopathologic response consisted of 15 (4%) CRs, 59 (17%) nCRs, 188 (55%) PRs, and 79 (23%) NRs. Patients who received chemotherapy alone had the worst responses (n = 21 for NR, 48%) as compared to patients who received chemoradiation alone (n = 25 for NR, 24%) or patients who received both therapies (n = 33 for NR, 17%) (Table 1; p = 0.001). Median overall survival for all 341 patients was 39 months; OS by histopathologic subtype was not reached (CR), 49 months (nCR), 38 months (PR), and 34 months (NR), respectively (p = 0.004). Of the 341 patients, 208 (61%) had N0 disease, 97 (28%) had N1 disease, and 36 (11%) had N2 disease. In an adjusted hazards model, modified Ryan score of PR or NR (HR: 1.71; 95% CI: 1.15–2.54; p = 0.008) and N1 (HR: 1.42; 95% CI: 1.1.02–2.01; p = 0.04), or N2 disease (HR: 2.54, 95% CI: 1.64–3.93; p < 0.001) were associated with increased risk of death.

Conclusions: Neoadjuvant chemotherapy alone is associated with lower rates of pathologic response. Patients with CR or nCR have a significantly improved OS as compared to patients with PR or NR. Nodal status is the most important pathologic prognostic factor. Neoadjuvant chemoradiation may be an important driver of pathologic response.

Abstract 936: Regulation of CD8+ T-cell function and antitumor activity by DGKα and DGKζ

Diacylglycerol kinases (DGKs) are a family of enzymes that metabolize the lipid diacylglycerol (DAG) to form phosphatidic acid. In T cells, two isoforms of DGK, DGKα and DGKζ, serve an important role in dampening signal transduction downstream of the T cell receptor (TCR), where they phosphorylate DAG generated by PLCγ1 after activation of proximal signaling molecules. DAG generated downstream of TCR binds to Protein Kinase C θ (PKCθ) and Ras Guanyl Releasing Protein 1 (RasGRP1), facilitating T cell activation. Elimination of either DGK isoform leads to increased generation of DAG and subsequent strengthened signaling downstream of RasGRP1 and PKCθ. Functionally, this results in formation of CD8+ T cells with enhanced cytokine production and proliferation after TCR stimulation. While mice or CD8+ T cells deficient in DGKα or DGKζ are both known to demonstrate enhanced immune responses to tumor, there has not been, to date, a direct comparison of the anti-tumor activity between mice lacking the two isoforms. We sought to determine which isoform of DGK more intensely attenuated anti-tumor immunity in order to identify which would be a better target for immune-based cancer therapies. We inoculated C57BL/6 mice with a variety of syngeneic tumor cell lines - MC38 colon carcinoma, B16F1 melanoma, and C1498 leukemia - and directly compared survival and tumor growth between mice deficient in DGKα or DGKζ in the presence or absence of anti-PD1 treatment. We found that DGKζ-/- mice more efficiently suppressed growth of subcutaneously implanted tumor cells when compared with DGKα-/- mice across the three model systems and further observed that the combination of DGKζ-deficiency and anti-PD1 were additive in tumor control. Additionally, relative to wildtype CD8+ T cells, we found that DGKζ-/- CD8+ T cells demonstrated qualitatively enhanced mRNA changes as assessed by RNA-seq analysis of cells after TCR stimulation. Pathway analyses from RNA-seq similarly indicated enhanced quantitative changes in DGKζ-/- T cells relative to DGKα-/- T cells, findings confirmed with in vitro biochemical and functional assays. Lastly, using CRISPR-based approaches to eliminate DGKα or DGKζ, we observed similar biochemical changes in human T cells when compared with T cells from gene-deficient mice. Our data, employing genetic approaches to modulate DGKα or DGKζ in both human and mouse models, suggests that DGKζ is a dominant regulator of TCR driven T cell activation and is consistent with the observed superior anti-tumor immune response.

Citation Format: Susan Wee, Junchen Gu, Cindy Wang, Carolyn Cao, Sandra Holzhauer, Heshani Desilva, Erin Wesley, Susan Tsai, Douglas Evans, Matthew Riese. Regulation of CD8+ T-cell function and antitumor activity by DGKα and DGKζ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 936.

Dextran Enhances the Lentiviral Transduction Efficiency of Murine and Human Primary NK Cells

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining the role of the gene of interest in the development, differentiation, and function of NK cells. Recent advances related to chimeric antigen receptors (CARs) in cancer immunotherapy accentuate the need for an efficient method to deliver exogenous genes to effector lymphocytes. The efficiencies of lentiviral-mediated gene transductions into primary human or mouse NK cells remain significantly low, which is a major limiting factor. Recent advances using cationic polymers, such as polybrene, show an improved gene transduction efficiency in T cells. However, these products failed to improve the transduction efficiencies of NK cells. This work shows that dextran, a branched glucan polysaccharide, significantly improves the transduction efficiency of human and mouse primary NK cells. This highly reproducible transduction methodology provides a competent tool for transducing human primary NK cells, which can vastly improve clinical gene delivery applications and thus NK cell-based cancer immunotherapy.

Adoptive cell therapy using PD-1+ myeloma-reactive T cells eliminates established myeloma in mice

Background

Adoptive cellular therapy (ACT) with cancer antigen-reactive T cells following lymphodepletive pre-conditioning has emerged as a potentially curative therapy for patients with advanced cancers. However, identification and enrichment of appropriate T cell subsets for cancer eradication remains a major challenge for hematologic cancers.

Methods

PD-1⁺ and PD-1⁻ T cell subsets from myeloma-bearing mice were sorted and analyzed for myeloma reactivity in vitro. In addition, the T cells were activated and expanded in culture and given to syngeneic myeloma-bearing mice as ACT.

Results

Myeloma-reactive T cells were enriched in the PD-1⁺ cell subset. Similar results were also observed in a mouse AML model. PD-1⁺ T cells from myeloma-bearing mice were found to be functional, they could be activated and expanded ex vivo, and they maintained their anti-myeloma reactivity after expansion. Adoptive transfer of ex vivo-expanded PD-1⁺ T cells together with a PD-L1 blocking antibody eliminated established myeloma in Rag-deficient mice. Both CD8 and CD4 T cell subsets were important for eradicating myeloma. Adoptively transferred PD-1⁺ T cells persisted in recipient mice and were able to mount an adaptive memory immune response.

Conclusions

These results demonstrate that PD-1 is a biomarker for functional myeloma-specific T cells, and that activated and expanded PD-1⁺ T cells can be effective as ACT for myeloma. Furthermore, this strategy could be useful for treating other hematologic cancers.

Academic Cancer Center Phase I Program Development

This commentary assesses the factors necessary for the effectiveness of academic phase I cancer programs. The metrics presented here may be useful as a rubric for new and established programs.

Multiple factors critical to the effectiveness of academic phase I cancer programs were assessed among 16 academic centers in the U.S. Successful cancer centers were defined as having broad phase I and I/II clinical trial portfolios, multiple investigator‐initiated studies, and correlative science. The most significant elements were institutional philanthropic support, experienced clinical research managers, robust institutional basic research, institutional administrative efforts to reduce bureaucratic regulatory delays, phase I navigators to inform patients and physicians of new studies, and a large cancer center patient base. New programs may benefit from a separate stand‐alone operation, but mature phase I programs work well when many of the activities are transferred to disease‐oriented teams. The metrics may be useful as a rubric for new and established academic phase I programs.

Extending water vapor trend observations over Boulder into the tropopause region: Trend uncertainties and resulting radiative forcing

Thirty years of balloon-borne measurements over Boulder (40°N, 105°W) are used to investigate the water vapor trend in the tropopause region. This analysis extends previously published trends, usually focusing on altitudes greater than 16 km, to lower altitudes. Two new concepts are applied: (1) Trends are presented in a thermal tropopause (TP) relative coordinate system from -2 km below to 10 km above the TP, and (2) sonde profiles are selected according to TP height. Tropical (TP _z > 14 km), extratropical (TP _z < 12 km), and transitional air mass types (12 km < TP _z < 14 km) reveal three different water vapor reservoirs. The analysis based on these concepts reduces the dynamically induced water vapor variability at the TP and principally favors refined water vapor trend studies in the upper troposphere and lower stratosphere. Nonetheless, this study shows how uncertain trends are at altitudes -2 to +4 km around the TP. This uncertainty in turn has an influence on the uncertainty and interpretation of water vapor radiative effects at the TP, which are locally estimated for the 30 year period to be of uncertain sign. The much discussed decrease in water vapor at the beginning of 2001 is not detectable between -2 and 2 km around the TP. On lower stratospheric isentropes, the water vapor change at the beginning of 2001 is more intense for extratropical than for tropical air mass types. This suggests a possible link with changing dynamics above the jet stream such as changes in the shallow branch of the Brewer-Dobson circulation.

Abstract A3: Enhanced effector responses in CAR-redirected CD8+ T cells deficient in diacylglycerol kinases

The use of chimeric antigen receptor (CAR)-redirected CD8+ T cells in the treatment of malignancy is a novel strategy that has shown tremendous promise; however, it remains likely this strategy could be enhanced when combined with additional approaches. We hypothesized that deletion of signaling mediators that negatively regulate TCR signal transduction might enhance CAR signaling and function, since CARs utilize the same machinery that transduces TCR signals. We tested CAR activity and function in T cells that lacked one or both lymphocyte-specific isoforms of diacylglycerol kinase (dgk), proteins that metabolize the second messenger 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. 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 a potential target for improving the clinical potential of CARs.

Citation Format: Matthew Riese, Liang-Chuan Wang, Anjana Ranganathan, Gary Koretzky, Steven Albelda. Enhanced effector responses in CAR-redirected CD8+ T cells deficient in diacylglycerol kinases. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr A3.

Mass-analyzed threshold ionization spectroscopy of pyrimidine: determining the geometry in the first excited and the ionic ground states

Vibrational spectra of the pyrimidine cation in the electronic ground state were measured via several intermediate states of the first excited state (0(0),16a(1), 16a(2), 16a(4), 16b(1), 10b(1), 6b(2), 6a(1), 1(1), 4(1), 4(2) and 12(1)) by mass-analyzed threshold ionization spectroscopy. For the first time, several vibrational modes could be assigned in the first excited and the ionic ground states. Anharmonic coupling is shown to occur in the first excited state due to Fermi resonance between the 1(1) and the 16a(4) vibrations. From the results of the measurements and calculations presented here, pyrimidine is predicted to be planar in the first excited and the ionic ground states, and it belongs to the C(2V) point group.

Mass-analyzed threshold ionization spectroscopy of pyridine. Structural distortion in the first excited state

For the first time, vibrational spectra of the pyridine cation in the electronic ground state have been measured via several intermediate states (0(0), 16b0(2), 16b0(4), 6a0(1), 6b(1), 16a0(1), 10a0(1) and 12(1)) by Mass-Analyzed Threshold Ionization (MATI) spectroscopy. From the MATI spectra, the adiabatic ionization energy of pyridine has been determined to be 74,185 +/- 6 cm(-1) (9.1978 +/- 0.0008 eV). Several vibronic modes in the ionic ground state could be assigned for the first time. An intensity gain of vibrations having b1 symmetry could be observed by activating the ion ground state. Also, a breakdown of the "delta nu = 0 propensity rule" for the excitation via the 16b(2) and 16b(4) states of the first excited states are displayed in the recorded spectra. In conjunction with ab initio calculations these observations can be explained by a strong geometrical distortion along the 16b vibration in the first excited state, leading to a "boat distortion".

Isolation and characterization of new MIKC*-Type MADS-box genes from the moss Physcomitrella patens

MADS-box genes encode for a large family of transcription-regulating proteins, which were isolated from all groups of eukaryotic organisms. The plant-specific MIKC-type MADS-box genes have been intensively analyzed for their roles in controlling developmental processes. Well-known are the MADS-box genes acting as homeotic selector genes in the differentiation of whorls of floral organs in seed plants. The MADS-box gene family has also been studied in non-flowering plants, such as lycophytes, pteridophytes, and bryophytes. The analysis of MADS-box genes in the moss Physcomitrella patens led to the identification of a new class of MIKC-type genes, designated as MIKC*-type genes. The MIKC*-type genes possess a number of structural features which clearly distinguish them from the already known MIKC-type genes. Recently, orthologues of the Physcomitrella MIKC*-type genes were found in Arabidopsis thaliana, demonstrating the conservation of these genes in tracheophytes. Here, we report the isolation of two new MIKC*-type MADS-box genes from Physcomitrella. Structural features and expression patterns of these genes were analyzed. The contribution of our findings to a better understanding of the evolution of MIKC*-type genes in land plants is discussed.