Principles for secondary traumatic stress-responsive practice: An expert consensus approach

OBJECTIVE

Though research on secondary traumatic stress (STS) has greatly increased in the past decade, to date the field lacks a coherent set of guiding principles for practice that behavioral health providers and organizations can use to mitigate the occurrence and impact of STS. As such it is important to identify effective strategies, grounded in research and professional experience, to reduce the occurrence and impact of STS among behavioral health professionals and organizations.

METHOD

We conducted a four-stage modified Delphi survey. Thirty-one international STS experts were invited to participate, with a minimum of 19 responding in each round. Thematic analysis was conducted on qualitative data, which was incorporated into revisions of the principles.

RESULTS

Consensus was achieved on 14 principles, seven targeted at individual professionals, and seven targeted at organizations.

CONCLUSIONS

This is the first effort to delineate principles for practice intended to reduce the occurrence and impact of STS in individual and organizational practice in behavioral health services. The principles are intended to inform best practices for individuals and organizations providing services to persons and communities who have experienced trauma and thereby improve the quality and effectiveness of services to traumatized populations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A synthetic lethal screen for Snail-induced enzalutamide resistance identifies JAK/STAT signaling as a therapeutic vulnerability in prostate cancer

Despite substantial improvements in the treatment landscape of prostate cancer, the evolution of hormone therapy-resistant and metastatic prostate cancer remains a major cause of cancer-related death globally. The mainstay of treatment for advanced prostate cancer is targeting of androgen receptor signaling, including androgen deprivation therapy plus second-generation androgen receptor blockade (e.g., enzalutamide, apalutamide, darolutamide), and/or androgen synthesis inhibition (abiraterone). While these agents have significantly prolonged the lives of patients with advanced prostate cancer, is nearly universal. This therapy resistance is mediated by diverse mechanisms, including both androgen receptor-dependent mechanisms, such as androgen receptor mutations, amplifications, alternative splicing, and amplification, as well as non-androgen receptor-mediated mechanisms, such as lineage plasticity toward neuroendocrine-like or epithelial-mesenchymal transition (EMT)-like lineages. Our prior work identified the EMT transcriptional regulator Snail as critical to hormonal therapy resistance and is commonly detected in human metastatic prostate cancer. In the current study, we sought to interrogate the actionable landscape of EMT-mediated hormone therapy resistant prostate cancer to identify synthetic lethality and collateral sensitivity approaches to treating this aggressive, therapy-resistant disease state. Using a combination of high-throughput drug screens and multi-parameter phenotyping by confluence imaging, ATP production, and phenotypic plasticity reporters of EMT, we identified candidate synthetic lethalities to Snail-mediated EMT in prostate cancer. These analyses identified multiple actionable targets, such as XPO1, PI3K/mTOR, aurora kinases, c-MET, polo-like kinases, and JAK/STAT as synthetic lethalities in Snail+ prostate cancer. We validated these targets in a subsequent validation screen in an LNCaP-derived model of resistance to sequential androgen deprivation and enzalutamide. This follow-up screen provided validation of inhibitors of JAK/STAT and PI3K/mTOR as therapeutic vulnerabilities for both Snail+ and enzalutamide-resistant prostate cancer.

Abstract A08: Divergent tumor cell states in neuroblastoma possess distinct immunogenic phenotypes

Active immunotherapy approaches for neuroblastoma (NB), a pediatric cancer of the sympathetic nervous system, has met with limited success. Especially challenging is the genetic heterogeneity of NB which makes it difficult to identify factors that consistently indicate the likelihood of an effective immune response and thereby select patients who are most likely to benefit from immunotherapy. Hence, we undertook an unbiased analysis of gene expression signatures from >500 well-annotated primary NBs representing diverse clinical and genetic subtypes to identify of predictors of immune response. Using clustering analysis of bulk transcriptomic signatures from these tumors, we identified a subset of NBs that was notable for the high expression of genes associated with anti-tumor immune response. These “immunogenic” tumors showed a predominance of gene expression signatures derived from malignant cells with primitive neural crest-like or mesenchymal properties, one of the two cell states that shape intratumoral heterogeneity in NB. In contrast, tumors that expressed committed, adrenergic neuron-like signatures were less immunogenic. Single-cell (sc) RNA-seq and immunohistochemistry analysis further confirmed that NBs comprise both adrenergic and mesenchymal tumor cells, and that the presence of mesenchymal cells positively associated with immune cell infiltration into the TME. scRNA-seq also revealed that mesenchymal NB cells were enriched for inflammatory gene signature. Gene expression analysis of isogenic pairs of adrenergic and mesenchymal cells showed that mesenchymal NBs differentially upregulate genes involved in regulating antigen processing and presentation, MHC class I expression, type-I interferon and TLR3 signaling, and NK cell activation. This is achieved through a permissive chromatin landscape at the promoters of these immune regulatory genes that support their high expression in mesenchymal cells. By contrast, in adrenergic cells, tumor-intrinsic immune genes are epigenetically silenced by the PRC2 complex and PRC2 inhibition leads to increased immune cell activation. Remarkably, induction of the mesenchymal state in adrenergic cells through transcriptional reprogramming by PRRX1 or therapy resistance is accompanied by the epigenetic activation of innate and adaptive immune response genes. Functionally, the inherent immunogenicity of mesenchymal cells promotes T cell infiltration by secreting inflammatory cytokines, enables efficient targeting by antigen-specific cytotoxic T and NK cells, and imparts responsiveness to immune checkpoint blockade in a syngeneic NB model. In conclusion, our study uncovers an unappreciated link between immunogenicity and tumor lineage state in NB, and rationalizes future interrogations into (i) avenues through which the vulnerability of mesenchymal cells to immune-mediated targeting could be harnessed clinically and (ii) how perturbation of epigenetically-regulated cell states could be harnessed to promote anti-tumor immune response.

Citation Format: Satyaki Sengupta, Sanjukta Das, Angela C. Crespo, Annelisa M. Cornel, Anand G. Patel, Navin R. Mahadevan, Marco Campisi, Alaa K. Ali, Bandana Sharma, Jared H. Rowe, Rogier Versteeg, Rudolf Jaenisch, Stefani Spranger, Rizwan Romee, Brian C. Miller, David A. Barbie, Stefan Nierkens, Michael A. Dyer, Judy Lieberman, Rani E. George. Divergent tumor cell states in neuroblastoma possess distinct immunogenic phenotypes [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr A08.

Microenvironmental Landscape of Human Melanoma Brain Metastases in Response to Immune Checkpoint Inhibition

Melanoma-derived brain metastases (MBM) represent an unmet clinical need because central nervous system progression is frequently an end stage of the disease. Immune checkpoint inhibitors (ICI) provide a clinical opportunity against MBM; however, the MBM tumor microenvironment (TME) has not been fully elucidated in the context of ICI. To dissect unique elements of the MBM TME and correlates of MBM response to ICI, we collected 32 fresh MBM and performed single-cell RNA sequencing of the MBM TME and T-cell receptor clonotyping on T cells from MBM and matched blood and extracranial lesions. We observed myeloid phenotypic heterogeneity in the MBM TME, most notably multiple distinct neutrophil states, including an IL8-expressing population that correlated with malignant cell epithelial-to-mesenchymal transition. In addition, we observed significant relationships between intracranial T-cell phenotypes and the distribution of T-cell clonotypes intracranially and peripherally. We found that the phenotype, clonotype, and overall number of MBM-infiltrating T cells were associated with response to ICI, suggesting that ICI-responsive MBMs interact with peripheral blood in a manner similar to extracranial lesions. These data identify unique features of the MBM TME that may represent potential targets to improve clinical outcomes for patients with MBM.

PI3K activation allows immune evasion by promoting an inhibitory myeloid tumor microenvironment

BACKGROUND

Oncogenes act in a cell-intrinsic way to promote tumorigenesis. Whether oncogenes also have a cell-extrinsic effect on suppressing the immune response to cancer is less well understood.

METHODS

We use an in vivo expression screen of known cancer-associated somatic mutations in mouse syngeneic tumor models treated with checkpoint blockade to identify oncogenes that promote immune evasion. We then validated candidates from this screen in vivo and analyzed the tumor immune microenvironment of tumors expressing mutant protein to identify mechanisms of immune evasion.

RESULTS

We found that expression of a catalytically active mutation in phospho-inositol 3 kinase (PI3K), PIK3CA c.3140A>G (H1047R) confers a selective growth advantage to tumors treated with immunotherapy that is reversed by pharmacological PI3K inhibition. PIK3CA H1047R-expression in tumors decreased the number of CD8⁺ T cells but increased the number of inhibitory myeloid cells following immunotherapy. Inhibition of myeloid infiltration by pharmacological or genetic modulation of Ccl2 in PIK3CA H1047R tumors restored sensitivity to programmed cell death protein 1 (PD-1) checkpoint blockade.

CONCLUSIONS

PI3K activation enables tumor immune evasion by promoting an inhibitory myeloid microenvironment. Activating mutations in PI3K may be useful as a biomarker of poor response to immunotherapy. Our data suggest that some oncogenes promote tumorigenesis by enabling tumor cells to avoid clearance by the immune system. Identification of those mechanisms can advance rational combination strategies to increase the efficacy of immunotherapy.

Association of clonal hematopoiesis with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is associated with age and smoking, but other determinants of the disease are incompletely understood. Clonal hematopoiesis of indeterminate potential (CHIP) is a common, age-related state in which somatic mutations in clonal blood populations induce aberrant inflammatory responses. Patients with CHIP have an elevated risk for cardiovascular disease, but the association of CHIP with COPD remains unclear. We analyzed whole-genome sequencing and whole-exome sequencing data to detect CHIP in 48 835 patients, of whom 8444 had moderate to very severe COPD, from four separate cohorts with COPD phenotyping and smoking history. We measured emphysema in murine models in which Tet2 was deleted in hematopoietic cells. In the COPDGene cohort, individuals with CHIP had risks of moderate-to-severe, severe, or very severe COPD that were 1.6 (adjusted 95% confidence interval [CI], 1.1-2.2) and 2.2 (adjusted 95% CI, 1.5-3.2) times greater than those for noncarriers. These findings were consistently observed in three additional cohorts and meta-analyses of all patients. CHIP was also associated with decreased FEV1% predicted in the COPDGene cohort (mean between-group differences, -5.7%; adjusted 95% CI, -8.8% to -2.6%), a finding replicated in additional cohorts. Smoke exposure was associated with a small but significant increased risk of having CHIP (odds ratio, 1.03 per 10 pack-years; 95% CI, 1.01-1.05 per 10 pack-years) in the meta-analysis of all patients. Inactivation of Tet2 in mouse hematopoietic cells exacerbated the development of emphysema and inflammation in models of cigarette smoke exposure. Somatic mutations in blood cells are associated with the development and severity of COPD, independent of age and cumulative smoke exposure.

Supporting the Next Generation of Scientists to Lead Cancer Immunology Research

Recent success in the use of immunotherapy for a broad range of cancers has propelled the field of cancer immunology to the forefront of cancer research. As more and more young investigators join the community of cancer immunologists, the Arthur L. Irving Family Foundation Cancer Immunology Symposium provided a platform to bring this expanding and vibrant community together and support the development of the future leaders in the field. This commentary outlines the lessons that emerged from the inaugural symposium highlighting the areas of scientific and career development that are essential for professional growth in the field of cancer immunology and beyond. Leading scientists and clinicians in the field provided their experience on the topics of scientific trajectory, career trajectory, publishing, fundraising, leadership, mentoring, and collaboration. Herein, we provide a conceptual and practical framework for career development to the broader scientific community.

Abstract NG04: Disrupting enhancers within the core epigenetic program of exhaustion improves CD8+ T cell responses and enhances tumor control

T cell exhaustion describes an acquired dysfunction common in settings of cancer and chronic viral infection. Despite clinical efforts to rescue exhaustion, the fundamental mechanisms specifying this state, and the potential for reprogramming exhausted T cells, remain poorly understood. We profiled accessible chromatin in chronic viral infection to show that exhausted CD8+ cells acquire a state-specific landscape of enhancers that profoundly differs from functional memory. By comparing antigen-specific T cells in several contexts of T cell dysfunction, we found that CD8+ tumor infiltrating lymphocytes share significant epigenetic and transcriptional features with chronic viral infection, highlighting that T cell exhaustion is a fundamental adaptation to settings of chronic stimulation. Critically, we identify a core epigenetic signature, independent of disease-specific milieu, that can act as a precise biomarker of the exhausted state. Comparison of mouse cells to those isolated from patients infected with HCV or HIV showed that the core epigenetic program of exhaustion is conserved across species. Importantly, curative therapy, which reduces viral antigen load, as well as checkpoint blockade immunotherapy, which reduces inhibitory T cell signaling, failed to reverse the exhausted epigenetic profile. T cell exhaustion is therefore a stable epigenetic state that is not rescued by common treatment modalities. We then sought new strategies to modulate T cell exhaustion. We identified a novel candidate enhancer near the PD-1 gene that is unique to exhausted CD8+ T cells and a component of the core epigenetic program. Using Cas9-mediated genome editing, we generated a novel mouse strain with germ-line deletion of this region to characterize the role of this enhancer in vivo. We observed 2-3-fold enrichment of PD-1 enhancer-null cells over control cells in chronic infection, suggesting that CD8+ T cells in these mice might be less prone to exhaustion. Importantly, PD-1 enhancer-null cells had increased persistence without any deficits in functionality as has been described with the full PD-1 gene knock-out. As a result, deletion of the PD-1 enhancer gave rise to significantly higher numbers of IFNg+ immunotherapy-responsive T cells compared to both WT and PD-1 gene ablation. These data suggest that deletion of a state-specific enhancer in immune cells can promote unique functional capacities from those observed with the full gene knock-out. Next, we wanted to understand the role of this enhancer in regulating CD8+ T cell responses in the tumor microenvironment. We found that PD-1 enhancer-null mice exhibit slower tumor growth and increased survival when challenged with either B16-ova melanoma or LLC-ova lung carcinoma. Moreover, PD-1 enhancer-null CD8+ T cells outcompete WT cells in the tumor and preferentially differentiate into functional effectors. The establishment of a core program of T cell exhaustion and increased insight into its epigenetic modulation has crucial implications for the future of immunotherapy. Furthermore, our work suggests that perturbing exhaustion-specific enhancers in T cells could be used to prevent sustained expression of inhibitory genes without damaging the gene locus itself in CAR-T based clinical trials, where there is intense interest in engineering against T cell exhaustion.

Citation Format: Debattama Sen, Sarah A. Weiss, Brian C. Miller, Kathleen B. Yates, Martin W. Lafleur, Arlene H. Sharpe, W. Nicholas Haining. Disrupting enhancers within the core epigenetic program of exhaustion improves CD8+ T cell responses and enhances tumor control [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr NG04.

Obesity Shapes Metabolism in the Tumor Microenvironment to Suppress Anti-Tumor Immunity

Obesity is a major cancer risk factor, but how differences in systemic metabolism change the tumor microenvironment (TME) and impact anti-tumor immunity is not understood. Here, we demonstrate that high-fat diet (HFD)-induced obesity impairs CD8⁺ T cell function in the murine TME, accelerating tumor growth. We generate a single-cell resolution atlas of cellular metabolism in the TME, detailing how it changes with diet-induced obesity. We find that tumor and CD8⁺ T cells display distinct metabolic adaptations to obesity. Tumor cells increase fat uptake with HFD, whereas tumor-infiltrating CD8⁺ T cells do not. These differential adaptations lead to altered fatty acid partitioning in HFD tumors, impairing CD8⁺ T cell infiltration and function. Blocking metabolic reprogramming by tumor cells in obese mice improves anti-tumor immunity. Analysis of human cancers reveals similar transcriptional changes in CD8⁺ T cell markers, suggesting interventions that exploit metabolism to improve cancer immunotherapy.

Abstract A83: Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade

T-cell dysfunction in the tumor microenvironment (TME) is a hallmark of many cancers. Reinvigoration of T-cell function by PD-1 checkpoint blockade can result in striking clinical responses, but is only effective in a minority of patients. The mechanisms by which anti-PD-1 therapy acts on exhausted T cells are not fully understood. Here we show that anti-PD-1 therapy acts on a specific subpopulation of CD8+ tumor-infiltrating lymphocytes (TILs) in melanoma mouse models, which can also be found in patients with melanoma. Exhausted CD8+ TILs contain a subpopulation of “progenitor exhausted” T cells with critical functional attributes that are not shared by the majority “terminally exhausted” TILs: they retain more polyfunctionality, persist following transfer into tumor-bearing mice, and differentiate to repopulate terminally exhausted TILs in the TME. As a result, progenitor exhausted CD8+ TILs are better able to control tumor growth than terminally exhausted cells. Progenitor exhausted, but not terminally exhausted, CD8+ TILs can respond to anti-PD-1 therapy. Melanoma patients with a higher percentage of progenitor exhausted cells have a longer duration of response to checkpoint blockade therapy. Therefore, approaches to expand progenitor exhausted CD8+ T cells in the tumor microenvironment may be an important component of improving checkpoint blockade response.

Citation Format: Brian C. Miller, Debattama R. Sen, Rose Al Abosy, Kevin Bi, Yamini Virkud, Martin W. LaFleur, Kathleen B. Yates, Ana Lako, Kristen Felt, Girish S. Naik, Michael Manos, Evisa Gjini, Jeffrey J. Ishizuka, F. Stephen Hodi, Scott J. Rodig, Arlene H. Sharpe, W. Nicholas Haining. Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr A83.

Abstract PR6: Disrupting enhancers within the core epigenetic program of exhaustion improves T-cell responses and enhances tumor control

T-cell exhaustion describes an acquired dysfunction common in settings of cancer and chronic viral infection. Despite clinical efforts to rescue exhaustion, the fundamental mechanisms specifying this state, and the potential for reprogramming exhausted T cells, remain poorly understood. We profiled accessible chromatin in chronic viral infection to show that exhausted CD8+ cells acquire a state-specific landscape of enhancers that profoundly differs from functional memory. Critically, CD8+ tumor-infiltrating lymphocytes shared significant epigenetic and transcriptional features with chronic viral infection, suggesting that T-cell exhaustion is a fundamental adaptation to settings of chronic stimulation. Comparison of mouse cells to those isolated from patients infected with HCV or HIV showed that the core epigenetic program of exhaustion is conserved across species. Importantly, curative therapy, which reduces viral antigen load, as well as anti-PD-1 immunotherapy, which reduces inhibitory T-cell signaling, failed to reverse the exhausted epigenetic profile. T-cell exhaustion is therefore a stable epigenetic state that is not rescued by common treatment modalities. We then sought new strategies to modulate T-cell exhaustion. We used Cas9-mediated genome editing to generate a novel mouse strain with germline deletion of a core exhaustion-associated enhancer near PD-1. We observed 2- to 3-fold enrichment in vivo of PD-1 enhancer-null cells over control cells in chronic infection, suggesting that CD8+ T cells in these mice might be less prone to exhaustion. PD-1 enhancer-null mice also exhibited slower tumor growth and increased survival when challenged with B16-ova melanoma. The establishment of a core program of T-cell exhaustion and increased insight into its epigenetic modulation has crucial implications for the future of immunotherapy and rational engineering of T cells for clinical use.

This abstract is also being presented as Poster A3.

Citation Format: Debattama R. Sen, Sarah A. Weiss, Brian C. Miller, Pierre Tonnerre, Rose Al Abosy, Kathleen B. Yates, Kevin Bi, Martin W. Lafleur, David Wolski, Lauer Georg, Arlene H. Sharpe, W. Nicholas Haining. Disrupting enhancers within the core epigenetic program of exhaustion improves T-cell responses and enhances tumor control [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr PR6.

Author Correction: Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

PTPN2 regulates the generation of exhausted CD8+ T cell subpopulations and restrains tumor immunity

CD8⁺ T cell exhaustion is a state of dysfunction acquired in chronic viral infection and cancer, characterized by the formation of Slamf6⁺ progenitor exhausted and Tim-3⁺ terminally exhausted subpopulations through unknown mechanisms. Here we establish the phosphatase PTPN2 as a new regulator of the differentiation of the terminally exhausted subpopulation that functions by attenuating type 1 interferon signaling. Deletion of Ptpn2 in CD8⁺ T cells increased the generation, proliferative capacity and cytotoxicity of Tim-3⁺ cells without altering Slamf6⁺ numbers during lymphocytic choriomeningitis virus clone 13 infection. Likewise, Ptpn2 deletion in CD8⁺ T cells enhanced Tim-3⁺ anti-tumor responses and improved tumor control. Deletion of Ptpn2 throughout the immune system resulted in MC38 tumor clearance and improved programmed cell death-1 checkpoint blockade responses to B16 tumors. Our results indicate that increasing the number of cytotoxic Tim-3⁺CD8⁺ T cells can promote effective anti-tumor immunity and implicate PTPN2 in immune cells as an attractive cancer immunotherapy target.

Abstract 2701: Functionally specialized subsets of exhausted CD8+ T cells mediate tumor control and differentially respond to checkpoint blockade

T cell dysfunction in the tumor microenvironment (TME) is a hallmark of many cancers. Reinvigoration of T cell function by PD-1 checkpoint blockade can result in striking clinical responses, but is only effective in a minority of patients. The basis for T cell dysfunction in the TME, as well as the mechanisms by which anti-PD-1 therapy acts on dysfunctional T cells are not fully understood. Here we show that anti-PD-1 therapy acts on a specific subpopulation of CD8+ tumor-infiltrating lymphocytes (TILs) in melanoma mouse models, which can also be found in patients with melanoma. We find that dysfunctional CD8+ TILs possess canonical epigenetic and transcriptional features of T cell exhaustion, mirroring those seen in chronic viral infection. Similar to chronic viral infection, exhausted CD8+ TILs contain a subpopulation of “progenitor exhausted” T cells that have a distinct regulatory state. Progenitor exhausted TILs also have critical functional attributes that are not shared by the majority “terminally exhausted” TILs: they retain more polyfunctionality, persist following transfer into tumor-bearing mice, and differentiate to repopulate terminally exhausted TILs in the TME. As a result, progenitor exhausted CD8+ TILs are better able to control tumor growth than terminally exhausted cells. Progenitor exhausted, but not terminally exhausted, CD8+ TILs can respond to anti-PD-1 therapy but this occurs without reversion of their exhausted epigenetic state. Human melanomas contain CD8+ T cells with a progenitor exhausted phenotype and patients with a higher fraction of this subpopulation in their tumors have a significantly longer duration of response to combination checkpoint blockade therapy. Therefore, approaches to expand progenitor exhausted CD8+ T cells in the tumor microenvironment may be an important component of improving checkpoint blockade response.

Citation Format: Brian C. Miller, Debattama R. Sen, Rose Al Abosy, Kevin Bi, Yamini V. Virkud, Martin W. LaFleur, Kathleen B. Yates, Ana Lako, Kristen Felt, Girish S. Naik, Michael Manos, Evisa Gjini, F. Stephen Hodi, Scott J. Rodig, Arlene H. Sharpe, W. Nicholas Haining. Functionally specialized subsets of exhausted CD8+ T cells mediate tumor control and differentially respond to checkpoint blockade [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 2701.

Subsets of exhausted CD8+ T cells differentially mediate tumor control and respond to checkpoint blockade

T cell dysfunction is a hallmark of many cancers, but the basis for T cell dysfunction and the mechanisms by which antibody blockade of the inhibitory receptor PD-1 (anti-PD-1) reinvigorates T cells are not fully understood. Here we show that such therapy acts on a specific subpopulation of exhausted CD8⁺ tumor-infiltrating lymphocytes (TILs). Dysfunctional CD8⁺ TILs possess canonical epigenetic and transcriptional features of exhaustion that mirror those seen in chronic viral infection. Exhausted CD8⁺ TILs include a subpopulation of 'progenitor exhausted' cells that retain polyfunctionality, persist long term and differentiate into 'terminally exhausted' TILs. Consequently, progenitor exhausted CD8⁺ TILs are better able to control tumor growth than are terminally exhausted T cells. Progenitor exhausted TILs can respond to anti-PD-1 therapy, but terminally exhausted TILs cannot. Patients with melanoma who have a higher percentage of progenitor exhausted cells experience a longer duration of response to checkpoint-blockade therapy. Thus, approaches to expand the population of progenitor exhausted CD8⁺ T cells might be an important component of improving the response to checkpoint blockade.

Abstract A216: Functionally specialized subsets of exhausted CD8+ T-cells mediate tumor control and response to checkpoint blockade

T-cell dysfunction in the tumor microenvironment (TME) is a hallmark of many cancers. Reinvigoration of T-cell function by PD-1 checkpoint blockade can result in striking clinical responses, but is effective only in a minority of patients. The basis for T-cell dysfunction in the TME, as well as the mechanisms by which anti-PD-1 therapy acts on dysfunctional T-cells are not fully understood. Here we show that anti-PD-1 therapy acts on a specific subpopulation of CD8+ tumor-infiltrating lymphocytes (TILs) in melanoma mouse models as well as patients with melanoma. We find that dysfunctional CD8+ TILs possess canonical epigenetic and transcriptional features of T-cell exhaustion, mirroring those seen in chronic viral infection. Similar to chronic viral infection, exhausted CD8+ TILs contain a subpopulation of “stem-like exhausted” T-cells that have a distinct regulatory state. Stem-like exhausted TILs also have critical functional attributes that are not shared by the majority “terminally exhausted” TILs: they retain more polyfunctionality, persist following transfer into tumor-bearing mice, and differentiate to repopulate terminally exhausted TILs in the TME. As a result, stem-like exhausted CD8+ TILs are better able to control tumor growth than terminally exhausted cells. Stem-like exhausted, but not terminally exhausted, CD8+ TILs can respond to anti-PD-1 therapy without reversion of their exhausted epigenetic state. CD8+ T-cells with a stem-like exhausted phenotype can be found in human melanoma samples and patients with a higher fraction of this subpopulation in their tumors have a significantly longer duration of response to combination checkpoint blockade therapy. Responsiveness to checkpoint blockade is therefore restricted to a subpopulation of exhausted TILs that retain specific functional properties which enable them to control tumors. Approaches to expand stem-like exhausted CD8+ T-cells in the tumor microenvironment may be an important component of improving checkpoint blockade response.

Citation Format: Debattama R. Sen, Brian C. Miller, Rose Al Abosy, Kevin Bi, Martin W. LaFleur, Kathleen B. Yates, Ana Lako, Kristen D. Felt, Girish S. Naik, Michael Manos, Evisa Gjini, Yamini V. Virkud, Stephen Hodi, Scott J. Rodig, Arlene H. Sharpe, W. Nicholas Haining. Functionally specialized subsets of exhausted CD8+ T-cells mediate tumor control and response to checkpoint blockade [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A216.

Abstract 706: In vivo tumor-associated mutation screen identifies PI3K activation as a mechanism of resistance to PD-1 blockade

Known genomic correlates of response to immunotherapy do not perfectly predict clinical outcome, supporting the existence of unknown mechanisms of resistance to tumor immunity. We hypothesize that somatic, cancer-associated mutations account for heterogeneity in spontaneous response to tumors and response to immunotherapy. We have undertaken a systematic in vivo screen to identify mechanisms of resistance to tumor immunity in order to define a comprehensive set of therapeutic targets and provide biomarkers of sensitivity to immunotherapy. Mouse tumor cell lines (MC38 colon carcinoma or B16 melanoma) were engineered to express a library of barcoded open reading frames (ORFs) mutagenized to encode known cancer-associated somatic mutations. Tumor-bearing animals were treated with anti-PD-1. A mutation in Phospho-Inositol 3 Kinase (PI3K), PIK3CA c.3140A>G, increased in representation in anti-PD-1 treated tumors but not in immunodeficient animals, suggesting that activity of the mutant allele conferred selective growth advantage in the setting of tumor immunity. This mutation encodes a constitutively active mutant catalytic domain, PIK3CA H1047R. MC38 tumors homogeneously expressing H1047R and implanted into wild-type mice failed to respond to anti-PD-1 therapy, while tumors expressing a control gene regressed. Pharmacologic PI3K inhibition resensitized tumors to treatment with anti-PD-1. PD-1-treated PIK3CA H1047R tumors had fewer infiltrating CD8+ T cells as measured by immunohistochemistry and flow cytometry. Single-cell RNA-seq of tumor-infiltrating immune cells revealed a population of myeloid cells expressing known immune inhibitory proteins that differentially enriched in PIK3CA H1047R-expressing tumors. Our data suggest that PI3K has, in addition to its well-described oncogenic role, a role in tumor immune evasion mediated by establishment of an inhibitory myeloid microenvironment. As such, activating mutations in PI3K may be useful as a biomarker of poor response to immunotherapy, and these studies provide a rationale for therapeutic combination trials of PI3K inhibition with checkpoint blockade and other myeloid-targeting immunotherapies.

Citation Format: Natalie B. Collins, Brian C. Miller, Kevin Bi, Rose Al Abosy, Kathleen Yates, Yashaswi Shrestha, John Doench, Jesse Boehm, W Nicholas Haining. In vivo tumor-associated mutation screen identifies PI3K activation as a mechanism of resistance to PD-1 blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 706.

Abstract 4683: Distinct subsets of dysfunctional CD8+ T cells underlie response to checkpoint blockade

T-cell exhaustion is a heterogeneous state, with recent work in chronic viral infections revealing at least two subtypes with different functional properties: "stem-like" and "terminal" exhausted cells. Whether these two populations exist in tumors and have different roles to control tumor growth remains unknown. We performed single-cell RNA-seq on exhausted CD8+ T cells from chronic virally infected mice, generating unique transcriptional signatures of both exhausted populations. By transcriptional enrichment and flow cytometry, we discovered both the stem-like and terminal exhausted populations in the B16 mouse melanoma model and confirmed their presence in human melanoma samples with multiplex immunofluorescence. ATAC-seq revealed that these two subpopulations are defined by state-specific changes in chromatin accessibility. These states are shared between exhausted CD8+ T cells from both viral and tumor models, demonstrating a common epigenetic program of T-cell dysfunction. The two populations have different functional properties, with the stem-like cells having a more polyfunctional cytokine response whereas terminal cells are more cytotoxic. When transferred into new tumor-bearing mice, stem-like cells were better able to control tumor growth, suggesting superior long-term functionality. Checkpoint blockade with anti-PD-1 is known to increase CD8+ T cell numbers in the tumor microenvironment, but it is not known which subpopulation responds to therapy. Treatment with anti-PD-1 antibody resulted in proliferation of the stem-like population, which differentiate into the more cytotoxic terminal exhausted cells. We have shown that two subpopulations of exhausted CD8+ T cells exist in mouse and human tumors, and anti-PD-1 therapy activates the stem-like CD8+ T cells to promote tumor control.

Citation Format: Brian C. Miller, Debattama R. Sen, Rose Al-Abosy, Kevin Bi, Kathleen B. Yates, Evisa Gjini, Kristen Felt, Robert T. Manguso, Scott J. Rodig, Arlene H. Sharpe, Nicholas Haining. Distinct subsets of dysfunctional CD8+ T cells underlie response to checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4683.

Ex Vivo Profiling of PD-1 Blockade Using Organotypic Tumor Spheroids

Ex vivo systems that incorporate features of the tumor microenvironment and model the dynamic response to immune checkpoint blockade (ICB) may facilitate efforts in precision immuno-oncology and the development of effective combination therapies. Here, we demonstrate the ability to interrogate ex vivo response to ICB using murine- and patient-derived organotypic tumor spheroids (MDOTS/PDOTS). MDOTS/PDOTS isolated from mouse and human tumors retain autologous lymphoid and myeloid cell populations and respond to ICB in short-term three-dimensional microfluidic culture. Response and resistance to ICB was recapitulated using MDOTS derived from established immunocompetent mouse tumor models. MDOTS profiling demonstrated that TBK1/IKKε inhibition enhanced response to PD-1 blockade, which effectively predicted tumor response in vivo Systematic profiling of secreted cytokines in PDOTS captured key features associated with response and resistance to PD-1 blockade. Thus, MDOTS/PDOTS profiling represents a novel platform to evaluate ICB using established murine models as well as clinically relevant patient specimens.Significance: Resistance to PD-1 blockade remains a challenge for many patients, and biomarkers to guide treatment are lacking. Here, we demonstrate feasibility of ex vivo profiling of PD-1 blockade to interrogate the tumor immune microenvironment, develop therapeutic combinations, and facilitate precision immuno-oncology efforts. Cancer Discov; 8(2); 196-215. ©2017 AACR.See related commentary by Balko and Sosman, p. 143See related article by Deng et al., p. 216This article is highlighted in the In This Issue feature, p. 127.

In vivo CRISPR screening identifies Ptpn2 as a cancer immunotherapy target

Immunotherapy with PD-1 checkpoint blockade is effective in only a minority of patients with cancer, suggesting that additional treatment strategies are needed. Here we use a pooled in vivo genetic screening approach using CRISPR-Cas9 genome editing in transplantable tumours in mice treated with immunotherapy to discover previously undescribed immunotherapy targets. We tested 2,368 genes expressed by melanoma cells to identify those that synergize with or cause resistance to checkpoint blockade. We recovered the known immune evasion molecules PD-L1 and CD47, and confirmed that defects in interferon-γ signalling caused resistance to immunotherapy. Tumours were sensitized to immunotherapy by deletion of genes involved in several diverse pathways, including NF-κB signalling, antigen presentation and the unfolded protein response. In addition, deletion of the protein tyrosine phosphatase PTPN2 in tumour cells increased the efficacy of immunotherapy by enhancing interferon-γ-mediated effects on antigen presentation and growth suppression. In vivo genetic screens in tumour models can identify new immunotherapy targets in unanticipated pathways.

Abstract 3027: Dissecting mechanisms of anti-PD-1 therapy with massively parallel single-cell RNA-sequencing

Anti-PD-1 therapy is an important new treatment option for many different types of malignancies, but overall response rates are less than 40%. Limited understanding of how anti-PD-1 treatment changes the tumor immune microenvironment is a barrier to identifying rational combination therapies and understanding mechanisms of immunotherapy resistance. To overcome this barrier, we set out to understand the mechanisms by which anti-PD-1 therapy augments the anti-tumor immune response using single-cell genomics. We have developed a massively parallel single-cell RNA-sequencing platform (“Seq-Well”) that uses a fabricated chip with nearly 100,000 nanowells into which barcoded beads and individual cells are distributed prior to lysis and RNA capture. We used this platform to comprehensively define the global expression profile of all major immune lineages in the tumor microenvironment in a mouse tumor model of immunotherapy. Mice were implanted with the B16F10 melanoma transplantable model of cancer and treated with anti-PD-1 or control antibodies. Tumors were harvested and CD45+ tumor-infiltrating leukocytes isolated by FACS. In a single experiment we were able to sequence the transcriptomes of over 600 individual cells, allowing us to clearly distinguish different immune lineages within the tumor microenvironment. We detect two transcriptionally distinct populations of CD8+ T cells, one that is highly proliferative (as marked by Ki-67), and one that has higher expression of cytotoxic markers (i.e. perforin). The Ki-67hi population is enriched for a gene expression signature from terminally exhausted CD8+ T cells in chronic viral infection, suggesting that this is a more exhausted subset. Treatment with anti-PD-1 globally alters the tumor microenvironment, including enriching for CD8+ T cells in the Prfhi subpopulation compared with the Ki-67hi more terminally exhausted population. Studies to understand changes in the immune infiltrate of immunotherapy resistant tumors are currently ongoing. In conclusion, massively parallel single-cell RNA-sequencing allows us to dissect the mechanisms by which checkpoint blockade controls tumor growth, revealing shifts in the differentiation state of exhausted CD8+ T cells induced by checkpoint blockade.

Citation Format: Brian C. Miller, Marc H. Wadsworth, Kevin Bi, Travis K. Hughes, Robert Manguso, Arlene H. Sharpe, Alex K. Shalek, Nicholas Haining. Dissecting mechanisms of anti-PD-1 therapy with massively parallel single-cell RNA-sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3027. doi:10.1158/1538-7445.AM2017-3027

Abstract 1019: In vivo CRISPR screening identifies Ptpn2 as a target for cancer immunotherapy

Despite the dramatic clinical success of cancer immunotherapy with PD-1 checkpoint blockade, most patients don’t experience sustained clinical benefit, suggesting that additional therapeutic strategies are needed. Functional genomic screens in cancer cells to discover new therapeutic targets are usually carried out in vitro where interaction with the immune system is absent. Here we report a pooled, loss-of-function genetic screening approach using CRISPR/Cas9 genome editing that is conducted in vivo in mouse transplantable tumors treated with vaccination and PD-1 checkpoint blockade. We tested 2,400 genes expressed by melanoma cells for those that synergize with or cause resistance to checkpoint blockade, and recovered the known immune evasion molecules, PD-L1 and CD47. Loss of function of multiple genes required to sense interferon-y caused resistance to immunotherapy. Deletion of Ptpn2, a pleotropic protein tyrosine phosphatase improved response to immunotherapy. In vivo, Ptpn2 deficient tumors showed increased infiltration of activated CD8+T cells. In vitro, Ptpn2 loss by tumor cells increased antigen presentation to T cells. Biochemical, transcriptional and genetic epistasis experiments demonstrated that loss of function of Ptpn2 sensitizes tumors to immunotherapy by enhancing interferon-y-mediated effects on the tumor cell. Thus, augmenting interferon-y signaling in tumor cells could increase the efficacy of immunotherapy. More generally, in vivo genetic screens in tumor models can identify new immunotherapy targets and rationally prioritize combination therapies.

Citation Format: Robert T. Manguso, Hans W. Pope, Margaret D. Zimmer, Flavian D. Brown, Kathleen B. Yates, Brian C. Miller, Natalie B. Collins, Kevin Bi, Martin W. Lafleur, Vikram R. Juneja, Sarah A. Weiss, David E. Fisher, David E. Root, Arlene H. Sharpe, John G. Doench, W Nicholas Haining. In vivo CRISPR screening identifies Ptpn2 as a target for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1019. doi:10.1158/1538-7445.AM2017-1019

Abstract PR11: Dissecting mechanisms of PD-1 blockade with single-cell RNA-sequencing

Anti-PD-1 therapy is an important new treatment option for many different types of malignancies, but overall response rates are less than 40%. We do not yet understand which patients will benefit and what resistance mechanisms allow tumor escape. The goal of this work is to understand the mechanisms by which anti-PD-1 therapy augments the anti-tumor immune response at the cellular level. Given that anti-PD-1 therapy is thought to work by altering the immunosuppressive tumor microenvironment, efforts to improve its efficacy will require a deep understanding of this complicated milieu. This will require analysis of thousands of cells using methodology that avoids the pitfalls of current techniques that have either limited scope - flow cytometry, immunohistochemistry - or limited resolution - bulk RNA sequencing. To this end, we have developed a massively parallel single-cell RNA-sequencing platform (Seq-Well) that comprehensively defines the global expression profile of all major immune lineages in the tumor microenvironment. Seq-Well uses a fabricated chip with nearly 100,000 nanowells into which barcoded beads and individual cells are distributed prior to lysis and RNA capture. Mice were implanted with two different transplantable models of cancer (MC38 colon carcinoma or B16 melanoma) and treated with anti-PD-1 or control antibodies. Tumors were harvested and CD45+ tumor-infiltrating leukocytes isolated by FACS. Thousands of cells were sequenced using Seq-Well with a median recovery of approximately 1,000 genes/cell. This level of expression diversity allows us to clearly distinguish different cell populations within the tumor microenvironment. We detect two transcriptionally distinct populations of CD8+ T cells, one that is highly proliferative (as marked by Ki-67), and one that has higher expression of perforin and TIM-3. The Ki-67+ population is enriched for a gene expression signature characterized by effector CD8+ T cells early in viral infection, consistent with their more proliferative nature. We hypothesize that this cluster of CD8+ T cells is also more functional given this signature enrichment and its lower expression of TIM-3, a marker found on exhausted CD8+ T cells. Comparisons of anti-PD-1 treated and control treated tumors are ongoing. In conclusion, massively parallel single-cell RNA-sequencing is a promising technology for the analysis of tumor immune infiltrates that will allow us to address the mechanisms by which checkpoint blockade controls tumor growth. By advancing our knowledge of an important immune checkpoint therapy, we aim to better understand who will respond to therapy, what resistance mechanisms may develop, and how to augment therapeutic efficacy with additional treatments.

This abstract is also being presented as Poster A79.

Citation Format: Brian C. Miller, Marc H. Wadsworth 2nd, Kevin Bi, Travis K. Hughes, Arlene H. Sharpe, Alex K. Shalek, W. Nicholas Haining. Dissecting mechanisms of PD-1 blockade with single-cell RNA-sequencing. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr PR11.

CD19-Targeted CAR T Cells: A New Tool in the Fight against B Cell Malignancies

Adoptive cell immunotherapy is a novel tool in the fight against cancer. Serving both effector and memory functions for the immune system, T cells make an obvious candidate for adoptive cell immunotherapy. By modifying native T cells with a chimeric antigen receptor (CAR), these cells can theoretically be targeted against any extracellular antigen. To date, the best-studied and clinically validated CAR T cells recognize CD19, a cell surface molecule on B cells and B cell malignancies. These CD19-directed T cells have shown clinical utility in chronic lymphocytic leukemia, acute lymphoblastic leukemia (ALL), and non-Hodgkin's lymphomas, with some patients achieving long-term disease remissions after treatment. This review will briefly summarize the current data supporting the use of adoptively transferred CAR T cells for the treatment of CD19-positive malignancies. Given these exciting results, the Food and Drug Administration has granted a 'breakthrough' designation for several variations of CD19-directed CAR T cells for treatment of adult and pediatric relapsed/refractory ALL.

Invariant NKT cells require autophagy to coordinate proliferation and survival signals during differentiation

Autophagy regulates cell differentiation, proliferation, and survival in multiple cell types, including cells of the immune system. In this study, we examined the effects of a disruption of autophagy on the differentiation of invariant NKT (iNKT) cells. Using mice with a T lymphocyte-specific deletion of Atg5 or Atg7, two members of the macroautophagic pathway, we observed a profound decrease in the iNKT cell population. The deficit is cell-autonomous, and it acts predominantly to reduce the number of mature cells, as well as the function of peripheral iNKT cells. In the absence of autophagy, there is reduced progression of iNKT cells in the thymus through the cell cycle, as well as increased apoptosis of these cells. Importantly, the reduction in Th1-biased iNKT cells is most pronounced, leading to a selective reduction in iNKT cell-derived IFN-γ. Our findings highlight the unique metabolic and genetic requirements for the differentiation of iNKT cells.

Autophagy proteins regulate the secretory component of osteoclastic bone resorption

Osteoclasts resorb bone via the ruffled border, whose complex folds are generated by secretory lysosome fusion with bone-apposed plasma membrane. Lysosomal fusion with the plasmalemma results in acidification of the resorptive microenvironment and release of CatK to digest the organic matrix of bone. The means by which secretory lysosomes are directed to fuse with the ruffled border are enigmatic. We show that proteins essential for autophagy, including Atg5, Atg7, Atg4B, and LC3, are important for generating the osteoclast ruffled border, the secretory function of osteoclasts, and bone resorption in vitro and in vivo. Further, Rab7, which is required for osteoclast function, localizes to the ruffled border in an Atg5-dependent manner. Thus, autophagy proteins participate in polarized secretion of lysosomal contents into the extracellular space by directing lysosomes to fuse with the plasma membrane. These findings are in keeping with a putative link between autophagy genes and human skeletal homeostasis.

Identification of Atg5-dependent transcriptional changes and increases in mitochondrial mass in Atg5-deficient T lymphocytes

Autophagy is implicated in many functions of mammalian cells such as organelle recycling, survival and differentiation, and is essential for the maintenance of T and B lymphocytes. Here, we demonstrate that autophagy is a constitutive process during T cell development. Deletion of the essential autophagy genes Atg5 or Atg7 in T cells resulted in decreased thymocyte and peripheral T cell numbers, and Atg5-deficient T cells had a decrease in cell survival. We employed functional-genetic and integrative computational analyses to elucidate specific functions of the autophagic process in developing T-lineage lymphocytes. Our whole-genome transcriptional profiling identified a set of 699 genes differentially expressed in Atg5-deficient and Atg5-sufficient thymocytes (Atg5-dependent gene set). Strikingly, the Atg5-dependent gene set was dramatically enriched in genes encoding proteins associated with the mitochondrion. In support of a role for autophagy in mitochondrial maintenance in T lineage cells, the deletion of Atg5 led to increased mitochondrial mass in peripheral T cells. We also observed a correlation between mitochondrial mass and Annexin-V staining in peripheral T cells. We propose that autophagy is critical for mitochondrial maintenance and T cell survival. We speculate that, similar to its role in yeast or mammalian liver cells, autophagy is required in T cells for the removal of damaged or aging mitochondria and that this contributes to the cell death of autophagy-deficient T cells.

The autophagy gene ATG5 plays an essential role in B lymphocyte development

Macroautophagy (herein autophagy) is an evolutionarily conserved process, requiring the gene ATG5, by which cells degrade cytoplasmic constituents and organelles. Here we show that ATG5 is required for efficient B cell development and for the maintenance of B-1a B cell numbers. Deletion of ATG5 in B lymphocytes using Cre-LoxP technology or repopulation of irradiated mice with ATG5-/- fetal liver progenitors resulted in a dramatic reduction in B-1 B cells in the peritoneum. ATG5-/- progenitors exhibited a significant defect in B cell development at the pro- to pre-B cell transition, although a proportion of pre-B cells survived to populate the periphery. Inefficient B cell development in the bone marrow was associated with increased cell death, indicating that ATG5 is important for B cell survival during development. In addition, B-1a B cells require ATG5 for their maintenance in the periphery. We conclude that ATG5 is differentially required at discrete stages of development in distinct, but closely related, cell lineages.

Coronavirus replication does not require the autophagy gene ATG5

Macroautophagy (herein autophagy) is a cellular process, requiring ATG5, by which cells deliver double membrane-bound packets containing cytoplasm or cytoplasmic organelles to the lysosome. This process has been reported in some cases to be antiviral, while in other cases it has been reported to be required for efficient viral replication or release. A role for autophagy in RNA virus replication has been an attractive hypothesis because of the association of RNA virus replication with complex membrane rearrangements in the cytoplasm that can generate opposed double membranes. In this study we demonstrate that ATG5 is not required for murine hepatitis virus (MHV) replication n either bone marrow derived macrophages (BMMphi) lacking ATG5 by virtue of Crerecombinase ediated gene deletion or primary low passage murine ATG5(-/-) embryonic ibroblasts (pMEFs). We conclude that neither ATG5 nor an intact autophagic pathway re required for MHV replication or release.

Dating age and stage as correlates of adolescent sexual attitudes and behavior

Dating experiences, especially the type or stage of dating, have consistently been found to be related to premarital sexual behavior. Findings regarding the age at 1st date and sexual behavior have been less consistent. This paper examined the age at which dating began and the type of dating relationship as correlates of premarital sexual attitudes and behavior among mid-teen adolescents. The analyses were based on a sample of high school students (n=836), most of whom were between the ages of 15 and 18 when the surveys were conducted. Early dating, especially early steady dating, was related to permissive attitudes and to premarital sexual experience among both males and females. The relationship between early dating and intercourse experience was particulary strong among Mormons, a religious group which has institutionalized age 16 as the legitimate age to begin dating.

Academic goals, achievement, and age at first sexual intercourse: longitudinal, bidirectional influences

This study examined bidirectional relationships between age at first sexual intercourse and academic goals and achievement. It was hypothesized that lower educational goals and achievement would be associated with initiating sexual intercourse at a younger age, and that initiating sexual activity early would be associated with a decrease in subsequent academic achievement and goals. In longitudinal data spanning 11 years, evidence was found for bidirectional effects. One interpretation of these results is that adolescents with high educational goals and achievement delay having intercourse because of the perceived risks (e.g., pregnancy and sexually transmitted diseases may jeopardize their plans for the future). Conversely, adolescents who engage in sexual intercourse at young ages might undergo a change in attitudes, including reduced interest in academic achievement and goals. The specific educational variables most strongly related to adolescent sexual intercourse in this study differed substantially by race and gender.

Comparisons of adopted and nonadopted adolescents in a large, nationally representative sample

There are conflicting findings about whether adopted children have more psychological and behavioral problems than nonadoptees. Research results are discrepant partly because many previous studies were based on small clinical samples or on samples biased by self-selection. A nationally representative school survey (Add Health) was used to compare adopted (n = 1,587) and nonadopted adolescents (total N = 87,165) across a wide variety of measures. Standardized mean differences show that adopted adolescents are at higher risk in all of the domains examined, including school achievement and problems, substance use, psychological well-being, physical health, fighting, and lying to parents. Demographic and background variable breakdowns show that the effect sizes for differences between adopted and nonadopted adolescents were larger for males, younger or older adolescents, Hispanics or Asians, and adolescents living in group homes or with parents of low education. Distributional analyses revealed approximately a 1:1 ratio of adopted to nonadopted adolescents in the middle ranges of the outcome variables but a ratio of 3:1 or greater near the tails of the distributions. These data clearly show that more adopted adolescents have problems of various kinds than their nonadopted peers; effect sizes were small to moderate based on mean differences, but comparisons of distributions suggest much larger proportions of adopted than nonadopted adolescents at the extremes of salient outcome variables.

Adopted adolescents' overrepresentation in mental health counseling: adoptees' problems or parents' lower threshold for referral?

A larger proportion of adopted adolescents receive mental health counseling than do their nonadopted peers. Adoptees might have more problems that require counseling, or their adoptive parents might have a lower threshold for referral (or both).

OBJECTIVE

To test the hypothesis that both the extent of adolescents' problems and their adoption status would predict whether adolescents received psychological counseling, after controlling for family demographic characteristics.

METHOD

Two large data sets collected from 1994 through 1996 by the National Longitudinal Study of Adolescent Health (Add Health) were used. In parallel analyses of the 2 data sets, hierarchical logistic regression models were implemented to assess the incremental effects of problem behaviors, family characteristics, and adoption status on adolescents receiving counseling.

RESULTS

Selected adolescents' problems and family demographic characteristics were significant predictors for having received counseling, but, after controlling for these variables, adoptees were still about twice as likely as nonadoptees to have received counseling.

CONCLUSIONS

Prevalence of problems, adoptive family characteristics, and adoption status must all be taken into account to understand why adoptees are more likely to receive counseling. Clinicians should be sensitive to issues that are especially salient in adoptive families.

Changes in reports and incidence of child abuse following natural disasters

OBJECTIVE

The aim of this research was to investigate if there is a higher incidence of child abuse following major natural disasters.

METHODOLOGY

Child abuse reports and substantiations were analyzed, by county, for 1 year before and after Hurricane Hugo, the Loma Prieta Earthquake. and Hurricane Andrew. Counties were included if damage was widespread, the county was part of a presidential disaster declaration, and if there was a stable data collection system in place.

RESULTS

Based on analyses of numbers, rates, and proportions, child abuse reports were disproportionately higher in the quarter and half year following two of the three disaster events (Hurricane Hugo and Loma Prieta Earthquake).

CONCLUSIONS

Most, but not all, of the evidence presented indicates that child abuse escalates after major disasters. Conceptual and methodological issues need to be resolved to more conclusively answer the question about whether or not child abuse increases in the wake of natural disasters. Replications of this research are needed based on more recent disaster events.

Comparisons of adopted and nonadopted adolescents in a large, nationally representative sample

There are conflicting findings about whether adopted children have more psychological and behavioral problems than nonadoptees. Research results are discrepant partly because many previous studies were based on small clinical samples or on samples biased by self-selection. A nationally representative school survey (Add Health) was used to compare adopted (n = 1,587) and nonadopted adolescents (total N = 87,165) across a wide variety of measures. Standardized mean differences show that adopted adolescents are at higher risk in all of the domains examined, including school achievement and problems, substance use, psychological well-being, physical health, fighting, and lying to parents. Demographic and background variable breakdowns show that the effect sizes for differences between adopted and nonadopted adolescents were larger for males, younger or older adolescents, Hispanics or Asians, and adolescents living in group homes or with parents of low education. Distributional analyses revealed approximately a 1:1 ratio of adopted to nonadopted adolescents in the middle ranges of the outcome variables but a ratio of 3:1 or greater near the tails of the distributions. These data clearly show that more adopted adolescents have problems of various kinds than their nonadopted peers; effect sizes were small to moderate based on mean differences, but comparisons of distributions suggest much larger proportions of adopted than nonadopted adolescents at the extremes of salient outcome variables.

Identification of gamma-endorphin-generating enzyme as insulin-degrading enzyme

The EL-4 thymoma cell line contains a peptidase which converts beta-endorphin to beta-endorphin 1-17 (gamma-endorphin), beta-endorphin 1-18, and their corresponding C-terminal fragments. This enzyme was purified approximately 700-fold to a single band on an SDS-polyacrylamide gel (106 kDa) in 16% yield. Estimation of the native molecular weight by molecular sieve chromatography gave a value of approximately 220 kDa, indicating that this enzyme is a dimer. Peptide sequencing demonstrated this activity can be attributed to insulin degrading enzyme, a previously described member of the inverzincin family (Hooper, 1994). Kinetic studies with a number of peptide substrates indicate that the enzyme preferentially cleaves on the amino side of hydrophobic or basic residues. However, the substrate specificity is more complex since not all basic and hydrophobic residues in a peptide are cleaved. The enzyme exhibits a requirement for a P'2 residue. On the basis of kcat/K(m) values, insulin, growth hormone releasing factor, and beta-endorphin are nearly equivalent substrates for the enzyme; however, growth hormone releasing factor and beta-endorphin exhibit a 40-fold higher kcat, but a 10-fold decreased affinity relative to insulin. A role for insulin-degrading enzyme as both a beta-endorphin-processing and -inactivating enzyme is implicated from these studies.

A secreted peptidase involved in T cell beta-endorphin metabolism

Beta-endorphin metabolism by CD4+ and CD8+ T cells, and the thymoma cell line, EL4, was investigated. In all three cell types, extracellular beta-endorphin was metabolized exclusively by a secreted, metal-dependent, thiol peptidase. The enzyme activity is expressed constitutively in EL4 cells and following activation of CD4+ and CD8+ T cells with anti-CD3 antibody. The enzyme is not one of the proteinases associated with cytolytic T cells and does not appear to be identical with any previously described beta-endorphin metabolizing enzyme. The enzyme cleaves beta-endorphin at approximately equal rates at either of two sites to yield beta-endorphin(1-17) (which is gamma-endorphin), beta-endorphin(1-18), beta-endorphin(18-31) and beta-endorphin(19-31). Evidence in the literature indicates that these N- and C-terminal peptides which contain, respectively, the opioid and non-opioid receptor binding domains of beta-endorphin, are biologically active. Thus, it is likely that this new T cell peptidase has important immunoregulatory activity.

The effects of forced sexual intercourse on white female adolescents

In the 1987 National Survey of Children the question was asked: "Was there ever a time when you were forced to have sex against your will, or were you raped?" Among White females, aged 18-22, those who answered yes (n = 41) and no (n = 400) were compared on a number of social-psychological and sexual variables that might be thought of as outcomes affected by having had coercive sexual experience(s). Those who reported being forced to have sexual intercourse, compared to those who did not, had more permissive attitudes about 16-17-year-olds having intercourse and a younger age of first voluntary sexual intercourse themselves. They also had lower internal locus of control and higher depression scores, and they needed and received more psychological help than those not reporting forced sexual intercourse. Dividing the forced sexual intercourse group (FSI) into those reporting FSI before versus after their first date, and those whose FSI was before versus after age 12, yielded essentially the same findings. Even in the presence of multivariate control variables. FSI experience remained a significant predictor of age at first voluntary sexual intercourse, locus of control, depression, and perceived need for psychological help. These analyses of national survey data support the clinical perspective that forced sexual intercourse causes or exacerbates various sexual and psychological problems.

In vivo effects of lipopolysaccharide on hepatic free-NAD(P)(+)-linked redox states and cytosolic phosphorylation potential in 48-hour-fasted rats

This study was performed to determine the magnitude and time of onset of in vivo changes in hepatic bioenergetics in response to a sublethal dose of lipopolysaccharide (LPS), a bacterial endotoxin. Male rats (48-hour-fasted) were administered an intraperitoneal injection of LPS (5 mg/kg body weight) or vehicle alone, and the livers were freeze-clamped 5, 30, or 180 minutes or 24 hours later. Liver tissue was extracted with perchloric acid, and the metabolites necessary to calculate NAD(+)- and NADP(+)-linked redox states and the cytosolic phosphorylation potential were measured. There was no significant difference in hepatic cytosolic phosphorylation potential between LPS and control groups at any of the times investigated. This indicated that the ability of the liver to synthesize adenosine triphosphate (ATP) was not compromised under the conditions of the study. No changes in hepatic redox states were observed 5 or 30 minutes after LPS treatment. Three hours after LPS treatment, hepatic cytosolic and mitochondrial free-[NAD+]/[NADH] redox states and the cytosolic free-[NADP+]/[NADPH] redox state were more oxidized. By 24 hours, only NAD(+)-linked redox states were more oxidized than the time-matched controls. Hepatic urea content was elevated at both 3 and 24 hours, compatible with an increased rate of urea synthesis as a consequence of increased amino acid metabolism, whereas hepatic beta-hydroxybutyrate and total ketone bodies were decreased 24 hours after LPS treatment, indicating decreased hepatic ketogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of effective day treatment programming for persons with borderline personality disorder

Day treatment, or partial hospitalization, may have unique advantages for the treatment of patients with borderline personality disorder. Such treatment may offer patients the optimal level of intensiveness and containment, resulting in less regressive dependency and acting-out behavior. To be successful in treatment of patients with borderline personality disorder, a day treatment program should facilitate the patient's need to experience and express affect safely, optimize the program's ability to provide less restrictiveness than inpatient treatment but more sustained and intensive support than outpatient treatment, and use verbal and nonverbal approaches to help patients maintain primary responsibility for their well-being. A length of stay of three weeks allows patients to regain baseline functioning and resume long-term outpatient care. Treatment goals should be clear and resolvable in three weeks.

Methionine enkephalin is hydrolyzed by aminopeptidase N on CD4+ and CD8+ spleen T cells

Exogenous methionine enkephalin incubated with CD4+ or CD8+ T cells purified from murine spleen is metabolized primarily, if not exclusively, by aminopeptidase N (aminopeptidase M, EC 3.4.11.2), a membrane-anchored ectopeptidase. The enzyme activity is identified by its substrate specificity, sensitivity to inhibition by amastatin, and immunoreactivity with antibody to rat kidney aminopeptidase N. Activation of CD4+ T cells results in a small increase per cell in aminopeptidase N activity.

A method for obtaining 13C isotopomer populations in 13C-enriched glucose

13C NMR analysis of 13C-enriched glucose containing multiple isotopomers is hampered by chemical shift similarities of several carbon resonances and by the presence of two anomeric forms. A convenient and quantitative method of enzymatically oxidizing glucose to gluconate in tissue and perfusate extracts is presented. The six carbon resonances of the resulting 13C-enriched gluconate are fully resolved at high pH, thereby allowing a determination of the fractional population of each 13C isotopomer by 13C NMR. The utility of this method is demonstrated using the effluent from an isolated perfused liver containing 13C-enriched glucose produced by hepatic metabolism of sodium [1,2,3-13C3]propionate via the citric acid cycle and gluconeogenesis. An analysis of the gluconate C2 and C5 resonances in this sample showed that pentose phosphate activity was insignificant during this perfusion protocol. As demonstrated, this method provides a means of fully describing 13C isotopomer populations in enriched glucose samples where isotope may be derived from multiple metabolic pathways, thus expanding the scope of experimental design and enrichment strategies.

Methionine enkephalin metabolism by murine macrophage ectopeptidase(s)

Ectopeptidases which hydrolyze opioid and other neuropeptides have been identified in brain, kidney and intestine. In this study, identification of the enzymes metabolizing the opioid peptide methionine enkephalin (YGGFM) in murine macrophages was undertaken. Incubation of methionine enkephalin with intact murine peritoneal macrophages results in five products identified as Y, F, FM, GFM and GGFM by amino acid analysis and peptide microsequencing after fractionation by HPLC. The spectrum of metabolites results from at least two distinct aminopeptidase activities. The enzyme hydrolyzing YGGFM to GGFM is identified as the membrane-anchored aminopeptidase N (ApN; EC 3.4.11.2) based on its substrate specificity and inhibitor profile. A distinct bestatin and amastatin sensitive aminopeptidase catalyzes hydrolysis of GGFM to GFM. The macrophage ApN protein has a larger mass and is antigenically distinct from murine kidney ApN, which is suggested to result from glycosylation differences rather than expression of a distinct protein. The ApN catalytic activity and mRNA levels are increased in thioglycollate-elicited as compared to resident peritoneal macrophages. RT-PCR analysis identified a 0.7 kb fragment of the ApN coding sequence which was identical in mouse kidney and thioglycollate-elicited peritoneal macrophages and which has 89% identity with the corresponding rat kidney ApN cDNA sequence.

Endotoxin stimulation of liver parenchymal cell phosphofructokinase activity requires nonparenchymal cells

The rate of carbohydrate flux through phosphofructokinase (measured as the rate of [3-3H]glucose detritiation) was increased fourfold in rat liver parenchymal cells incubated with conditioned medium from lipopolysaccharide-stimulated adherent liver non-parenchymal cells. The rate was not affected in parenchymal cells incubated either with lipopolysaccharide directly or with conditioned medium from non-stimulated non-parenchymal cells. The stimulation of carbohydrate flux through phosphofructokinase by conditioned medium was not duplicated by peptide cytokines known to be released by lipopolysaccharide-activated liver non-parenchymal cells (interleukin-1, interleukin-6, tumor necrosis factor-alpha, and transforming growth factor-beta) or platelet activating factor. Furthermore, formation of the active conditioned medium was not prevented by inclusion of cycloheximide or dexamethasone to inhibit cytokine synthesis, or indomethacin or BW755c to inhibit arachidonic acid metabolism, during lipopolysaccharide-stimulation of the non-parenchymal cells. The results indicate that intercellular communication between lipopolysaccharide-stimulated liver non-parenchymal cells and parenchymal cells by soluble mediators is responsible for the stimulation of liver phosphofructokinase activity during endotoxin-induced shock. Studies to isolate and identify the factor(s) in the conditioned medium are currently in progress.