Individualised neoantigen therapy mRNA-4157 (V940) plus pembrolizumab versus pembrolizumab monotherapy in resected melanoma (KEYNOTE-942): a randomised, phase 2b study

BACKGROUND

Checkpoint inhibitors are standard adjuvant treatment for stage IIB-IV resected melanoma, but many patients recur. Our study aimed to evaluate whether mRNA-4157 (V940), a novel mRNA-based individualised neoantigen therapy, combined with pembrolizumab, improved recurrence-free survival and distant metastasis-free survival versus pembrolizumab monotherapy in resected high-risk melanoma.

METHODS

We did an open-label, randomised, phase 2b, adjuvant study of mRNA-4157 plus pembrolizumab versus pembrolizumab monotherapy in patients, enrolled from sites in the USA and Australia, with completely resected high-risk cutaneous melanoma. Patients with completely resected melanoma (stage IIIB-IV) were assigned 2:1 to receive open-label mRNA-4157 plus pembrolizumab or pembrolizumab monotherapy. mRNA-4157 was administered intramuscularly (maximum nine doses) and pembrolizumab intravenously (maximum 18 doses) in 3-week cycles. The primary endpoint was recurrence-free survival in the intention-to-treat population. This ongoing trial is registered at ClinicalTrials.gov, NCT03897881.

FINDINGS

From July 18, 2019, to Sept 30, 2021, 157 patients were assigned to mRNA-4157 plus pembrolizumab combination therapy (n=107) or pembrolizumab monotherapy (n=50); median follow-up was 23 months and 24 months, respectively. Recurrence-free survival was longer with combination versus monotherapy (hazard ratio [HR] for recurrence or death, 0·561 [95% CI 0·309-1·017]; two-sided p=0·053), with lower recurrence or death event rate (24 [22%] of 107 vs 20 [40%] of 50); 18-month recurrence-free survival was 79% (95% CI 69·0-85·6) versus 62% (46·9-74·3). Most treatment-related adverse events were grade 1-2. Grade ≥3 treatment-related adverse events occurred in 25% of patients in the combination group and 18% of patients in the monotherapy group, with no mRNA-4157-related grade 4-5 events. Immune-mediated adverse event frequency was similar for the combination (37 [36%]) and monotherapy (18 [36%]) groups.

INTERPRETATION

Adjuvant mRNA-4157 plus pembrolizumab prolonged recurrence-free survival versus pembrolizumab monotherapy in patients with resected high-risk melanoma and showed a manageable safety profile. These results provide evidence that an mRNA-based individualised neoantigen therapy might be beneficial in the adjuvant setting.

FUNDING

Moderna in collaboration with Merck Sharp & Dohme, a subsidiary of Merck & Co, Rahway, NJ, USA.

Two-component nematic superconductivity in 4Hb-TaS2

Most superconductors have an isotropic, single component order parameter and are well described by the standard (BCS) theory for superconductivity. Unconventional, multiple-component superconductors are exceptionally rare and are much less understood. Here, we combine scanning tunneling microscopy and angle-resolved macroscopic transport for studying the candidate chiral superconductor, 4Hb-TaS2. We reveal quasi-periodic one-dimensional modulations in the tunneling conductance accompanied by two-fold symmetric superconducting critical field. The strong modulation of the in-plane critical field, Hc2, points to a nematic, unconventional order parameter. However, the imaged vortex core is isotropic at low temperatures. We suggest a model that reconciles this apparent discrepancy and takes into account previously observed spontaneous time-reversal symmetry breaking at low temperatures. The model describes a competition between a dominating chiral superconducting order parameter and a nematic one. The latter emerges close to the normal phase. Our results strongly support the existence of two-component superconductivity in 4Hb-TaS2 and can provide valuable insights into other systems with coexistent charge order and superconductivity.

PSGL-1 Blockade Induces Classical Activation of Human Tumor-associated Macrophages

The immune suppressive microenvironment is a major culprit for difficult-to-treat solid cancers. Particularly, inhibitory tumor-associated macrophages (TAM) define the resistant nature of the tumor milieu. To define tumor-enabling mechanisms of TAMs, we analyzed molecular clinical datasets correlating cell surface receptors with the TAM infiltrate. Though P-selectin glycoprotein ligand-1 (PSGL-1) is found on other immune cells and functions as an adhesion molecule, PSGL-1 is highly expressed on TAMs across multiple tumor types. siRNA-mediated knockdown and antibody-mediated inhibition revealed a role for PSGL-1 in maintaining an immune suppressed macrophage state. PSGL-1 knockdown or inhibition enhanced proinflammatory mediator release across assays and donors in vitro. In several syngeneic mouse models, PSGL-1 blockade alone and in combination with PD-1 blockade reduced tumor growth. Using a humanized tumor model, we observed the proinflammatory TAM switch following treatment with an anti-PSGL-1 antibody. In ex vivo patient-derived tumor cultures, a PSGL-1 blocking antibody increased expression of macrophage-derived proinflammatory cytokines, as well as IFNγ, indicative of T-cell activation. Our data demonstrate that PSGL-1 blockade reprograms TAMs, offering a new therapeutic avenue to patients not responding to T-cell immunotherapies, as well as patients with tumors devoid of T cells.

SIGNIFICANCE

This work is a significant and actionable advance, as it offers a novel approach to treating patients with cancer who do not respond to T-cell checkpoint inhibitors, as well as to patients with tumors lacking T-cell infiltration. We expect that this mechanism will be applicable in multiple indications characterized by infiltration of TAMs.

Macrophages - Controlling the Bifurcation Between Tumor Existence or Regression

Macrophages are multifunctional cells that are employed by the tumor to further its growth and adaptation. While tumor-associated macrophages (TAMs) have widely diverse phenotypes, tumors coevolve with the ones that can promote tumorigenesis. Functionally, TAMs/myeloid cells constitute the largest negative influence on the tumor microenvironment and need to be reprogrammed in order to enable successful anti-tumor response in most tumors. It is predicted that successful TAM repolarization has the potential to become a staple of immuno-oncology across most indications.

Cost-effectiveness of two psychological treatments for the reduction of alcohol consumption

Background

Up to 7% of the Swedish population meets criteria for harmful use or alcohol dependency but only 10-20% seek treatment. One of the most recommended psychological treatments for controlled drinking is Motivational Enhancement Therapy (MET). Behavioural Self-Control Training (BSCT) is another treatment that is unique in that it is based on the psychology of learning and specifically focused on skills training. To our knowledge, no previous studies exist that evaluated the cost-effectiveness of BSCT for alcohol use disorders (AUD). The aim of this study is to assess the cost-effectiveness of BSCT compared to MET for patients with AUD aiming for controlled drinking over the longer-term from a societal perspective.

Methods

We modelled a cohort of patients with AUD who aim for controlled drinking, over a 10 year time horizon, and estimated the expected costs and outcomes of BSCT and MET. The model reflects the epidemiological transitions between drinking states, which reflect different levels of daily alcohol intake. Each drinking state is connected to temporary or long-term complications attributable to alcohol consumption, different costs and utilities. The data was sourced from a randomized trial evaluating the effectiveness of MET vs BSCT. Risks for complications and associated costs, utilities and mortality were sourced from the literature.

Results

Compared to MET, BSCT resulted in less total QALYs gained (4,7 vs 6,6 QALYs per patient). MET remains a cost effective treatment compared to BSCT [incremental cost-effectiveness ratio (ICER) = SEK 8497,79 per gained QALY] and a No Intervention scenario BSCT [incremental cost-effectiveness ratio (ICER) = SEK 16321,07 per gained QALY] at a threshold of 500.000 SEK per QALY.

Conclusions

This study suggests that MET should remain the recommended treatment for AUD patients with a goal of controlled drinking in favor of BSCT.

Key messages

• Motivational Enhancement Therapy should remain the recommended treatment for AUD patients with controlled drinking as their goal.

• A future study comparing Motivational Enhancemente Therapy to Behaivoral Self Control Training as recommended treatment in patients wanting to achieve abstinenece is suggested.

Evaluation of a universal early intervention for parents and children from birth to age five

Background

This study aimed to investigate the health and economic outcomes of a universal early intervention for parents and children, the Salut Programme, from birth to when the child completed five years of age.

Methods

This study adopted a retrospective observational design using routinely collected register data with respect to both exposures and outcomes from a county in northern Sweden. Areas that received care-as-usual (non-Salut area) were compared to areas where the Programme was implemented after 2006 (Salut area) in terms of: i) health outcomes, healthcare resource use and related costs around pregnancy, delivery and birth, and ii) healthcare resource use and related costs, as well as costs related to care of sick child. Costs were estimated for inpatient care and specialised outpatient care for mothers and children. Two analyses were conducted: a matched difference-in difference analysis using the total sample and an analysis including a longitudinal subsample.

Results

The longitudinal analysis on mothers who had given birth in both the pre- and post-measure periods showed that those that had been exposed to the Salut Programme, had on average 6% (95% CI 3-9%) more full-term pregnancies and 2% (95% CI 0.03-3%) more babies born within normal weight range, compared to mothers who had only care-as-usual. Savings were incurred in terms of outpatient care related costs for children of mothers in the Salut area ($826). The difference-in-difference analysis using the total sample did not result in any significant differences in health outcomes or cumulative resource use over time.

Conclusions

The Salut Programme achieved health gains at a reasonable cost for children and parents, and may lead to lower usage of outpatient care. Other indicators point towards positive effects but the small sample size may have led to underestimation of true differences. The current findings support the continuous investment in this early childhood programme.

Key messages

• The Salut Programme improves the health of children and parents at a low cost.

• The Salut Programme as a health promotion early intervention is value for money and should be included in the local policy investment agenda.

Abstract 5602: VTX-0811, a first-in-class PSGL-1 blocking monoclonal antibody, repolarizes tumor associated macrophages and induces inflammation in the tumor microenvironment, leading to suppression of tumor growth in pre-clinical studies

Suppressive myeloid cells in the tumor microenvironment (TME) are associated with poor survival of cancer patients and resistance to T cell checkpoint inhibitors. These myeloid cells shield cancer cells from the sentinel immune response and create a niche for tumor growth. Repolarizing immuno-suppressive myeloid populations in the TME attracted considerable interest from scientific community and several companies, and has produced early positive clinical data. One of the targets that potently sustains macrophage suppressive phenotypes and is highly expressed on tumor associated macrophages is PSGL-1. Blocking a previously unknown epitope on PSGL-1 triggers macrophage repolarization to a pro inflammatory state. We have determined that our therapeutic candidate VTX-0811, anti-PSGL-1 monoclonal antibody (mAb), repolarizes M2-like macrophages to a more M1-like state both phenotypically and functionally as assessed by primary in vitro macrophage assays. Transcriptomics profiling of M2c macrophages showed that VTX-0811 upregulated TNF-α/NF-κB and chemokine-mediated signaling, while downregulating oxidative phosphorylation, fatty acid metabolism, and Myc signaling pathways, consistent with a broad M2-to-M1 shift. Furthermore, repolarized macrophages enhanced inflammatory responses in complex primary multi-cellular assays.VTX-0811 also showed efficacy in a humanized mouse PDX model of melanoma. VTX-0811 suppressed tumor growth to a significantly greater degree compared with an anti-PD-1 mAb. At the cellular and molecular levels, the treatment led to an inflammatory microenvironment, including a reduced MDSC population, and increased systemic pro-inflammatory mediators. Compared with anti-PD-1 monotherapy, VTX-0811 alone and in combination with anti-PD-1 increased the fraction of CD8+ T cells among the infiltrating T cells. Significant combination effects of VTX-0811 plus anti-PD-1 were seen within the tumor tissue, spleen, and peripheral blood.Additionally, pre-clinical efficacy of VTX-0811 was demonstrated using ex vivo cultures of fresh patient-derived tumors that preserve cellular and molecular composition of the TME. VTX-0811 increased secretion of inflammatory cytokines and chemokines known to be involved in immune activation of the TME and fresh leukocyte recruitment, as well as linked to clinical response to T cell checkpoint inhibitors.VTX-0811 is a humanized high affinity IgG4/κ mAb that demonstrated safety in NHP primates up to 200mg/kg dosed weekly for 5 total doses. VTX-0811 does not induce activation of unstimulated PBMC or unstimulated blood-derived neutrophil or T cell cultures. These data provide biological and mechanistic support for advancing this program into the clinic with a first in human trial planned for early 2022.

Citation Format: Igor Feldman, Tatiana Novobrantseva, Ani Nguyen, Jessica Ritter, Mohammad Zafari, Denise Manfra, Susan Low, Steve Sazinsky, Michael Brehm, Boris Klebanov. VTX-0811, a first-in-class PSGL-1 blocking monoclonal antibody, repolarizes tumor associated macrophages and induces inflammation in the tumor microenvironment, leading to suppression of tumor growth in pre-clinical studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5602.

Abstract P105: Targeting VSIG4, a novel macrophage checkpoint, repolarizes suppressive macrophages which induces an inflammatory response in primary cell in vitro assays and fresh human tumor cultures

VSIG4 (V-set immunoglobulin-domain-containing 4) is a B7 family related protein with known roles as a complement receptor involved in pathogen clearance, via interactions with C3 fragments, as well as a negative regulator of T cell activation by an undetermined mechanism. VSIG4 is expressed in tumor associated macrophages with exquisite specificity. In cancer, increased expression of VSIG4 has been associated with worse survival in multiple indications, including non-small cell lung cancer, multiple myeloma, ovarian cancer, stomach cancer and glioma, suggesting an important role in tumor immune evasion. Based upon computational analysis of transcript data across thousands of primary cancer and normal tissue samples, we hypothesized that VSIG4 has an important regulatory role in promoting M2-like immune suppressive macrophages in the tumor microenvironment, and that targeting VSIG4 via a monoclonal antibody could relieve VSIG4-mediated macrophage suppression by repolarizing tumor associated macrophages (TAMs) to an inflammatory phenotype capable of coordinating an anti-tumor immune response. Through a series of in vitro and ex vivo assays we demonstrate that anti-VSIG4 antibodies repolarize M2 macrophages and induce an immune response culminating in T cell activation. Anti-VSIG4 antibodies upregulate pro-inflammatory cytokines in M-CSF plus IL-10 driven monocyte-derived M2c macrophages, as well as in TAM-like macrophages in vitro derived from monocytes cultured in the presence of ascites fluid from ovarian cancer patients. To determine whether anti-VSIG4-induced macrophage repolarization can activate T cells, monocyte-derived M2c macrophages were co-cultured with autologous T cells in the presence of staphylococcal enterotoxin B (SEB) activation and anti-VSIG4 antibodies. Here, anti-VSIG4 antibodies upregulate both pro-inflammatory myeloid-derived cytokines (GM-CSF) and T cell-derived cytokines (IFNγ). To extend these observations to a relevant translational model, we treated fresh, patient-derived tumor samples with anti-VSIG4 antibodies and relevant controls ex vivo. Across numerous patient-derived samples, which included multiple tumor types, anti-VSIG4 treatment resulted in a significant upregulation of cytokines involved in TAM repolarization and T cell activation, and chemokines involved in immune cell recruitment, at levels greater than observed by treatment with anti-PD-1 or a clinical macrophage repolarizing agent (anti-ILT-4). Taken together, these data suggest that VSIG4 represents a promising new target capable of stimulating an anti-cancer response via multiple key immune mechanisms.

Citation Format: Steve Sazinsky, Ani Nguyen, Mohammad Zafari, Ryan Phennicie, Joe Wahle, Veronica Komoroski, Kathryn Rooney, Craig Mizzoni, Boris Klebanov, Jessica Ritter, Denise Manfra, Igor Feldman, Tatiana Novobrantseva. Targeting VSIG4, a novel macrophage checkpoint, repolarizes suppressive macrophages which induces an inflammatory response in primary cell in vitro assays and fresh human tumor cultures [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P105.

Abstract P107: PSGL-1 blocking antibodies repolarize tumor associated macrophages, reduce suppressive myeloid populations and induce inflammation in the tumor microenvironment, leading to suppression of tumor growth

Suppressive myeloid populations in the tumor microenvironment are associated with worse survival of cancer patients and low effectiveness of T cell checkpoint inhibitors. Recently, several early clinical studies have produced positive data for therapies aimed at repolarizing suppressive myeloid populations in the tumor microenvironment. One new macrophage repolarizing target, PSGL-1, is expressed at high levels on immuno-suppressive TAMs and differentiated M2 macrophages. PSGL-1 has been shown to have an immune-modulatory activity, which includes its role in maintaining a suppressive functional macrophage state. To assess the ability of PSGL-1 antibodies to convert macrophages and the tumor microenvironment from an immuno-suppressive toward a pro-inflammatory state, we employed in vitro primary macrophage and multi-cellular assays, ex vivo patient-derived tumor cultures, and a humanized mouse PDX model. We have determined that our lead anti-PSGL-1 antibody repolarized M2-like macrophages to a more M1-like state both phenotypically and functionally as assessed in primary in vitro macrophage assays. Transcriptomics profiling of M2c macrophages showed that the anti-PSGL-1 antibody upregulated TNF-a/NF-kB and chemokine-mediated signaling, while downregulating oxidative phosphorylation, fatty acid metabolism and Myc signaling pathways, consistent with a broad M2-to-M1 shift of the macrophage state. Furthermore, these repolarized M1-like macrophages enhanced the inflammatory response in complex multi-cellular assays. The PSGL-1 antibody also showed efficacy in a humanized mouse PDX model of melanoma. The antibody suppressed tumor growth to a significantly greater degree compared to anti-PD-1. At the cellular and molecular levels, the anti-PSGL-1 treatment led to a more enhanced inflammatory microenvironment, including a reduced M2:M1 macrophage ratio, and an increase in systemic pro-inflammatory mediators. Compared to anti-PD-1 monotherapy, anti-PSGL-1 alone and in combination with anti-PD-1 increased the fraction of effector CD8+ T cells among the infiltrating T cells. Significant combination effects of anti-PSGL-1 plus anti-PD-1 were seen at the cellular and molecular levels within the tumor tissue, the spleen, and peripheral blood. Lastly, pre-clinical efficacy of our lead anti-PSGL-1 antibody was demonstrated using ex vivo cultures of fresh patient-derived tumors that preserve the cellular heterogeneity of the TME. Anti-PSGL-1 increased production of inflammatory cytokines and chemokines involved in immune activation of the TME and T cell recruitment. The data presented here provide biological and mechanistic support for clinical testing of antibodies targeting PSGL-1 for the treatment of cancer.

Citation Format: Ani Nguyen, Jessica Ritter, Mohammad Zafari, Denise Manfra, Veronica Komoroski, Brian O'Nuallain, Ryan Phennicie, Kevin Kauffman, Dominika Nowakowska, Joe Wahle, Steve Sazinsky, Michael Brehm, Igor Feldman, Tatiana Novobrantseva. PSGL-1 blocking antibodies repolarize tumor associated macrophages, reduce suppressive myeloid populations and induce inflammation in the tumor microenvironment, leading to suppression of tumor growth [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P107.

886 Targeting VSIG4, a novel macrophage checkpoint, repolarizes suppressive macrophages which induces an inflammatory response in primary cell in vitro assays and fresh human tumor cultures

Background

VSIG4 (V-set immunoglobulin-domain-containing 4) is a B7 family related protein with known roles as a complement receptor involved in pathogen clearance as well as a negative regulator of T cell activation by an undetermined mechanism.1–3 VSIG4 is expressed in tumor associated macrophages (TAMs) with exquisite specificity. In cancer, increased expression of VSIG4 has been associated with worse survival in multiple indications, including non-small cell lung cancer, multiple myeloma, ovarian cancer, and glioma, suggesting an important role in tumor immune evasion.3–6 Based upon computational analysis of transcript data across thousands of primary cancer and normal tissue samples, we hypothesized that VSIG4 has an important regulatory role in promoting M2-like immune suppressive macrophages in the tumor microenvironment, and that targeting VSIG4 via a monoclonal antibody could relieve VSIG4-mediated macrophage suppression by repolarizing TAMs to an inflammatory phenotype capable of coordinating an anti-tumor immune response.

Methods

The ability of anti-VSIG4 antibodies to repolarize M2-like macrophages and induce T cell activation was assessed in vitro and ex vivo, by measuring production of inflammatory mediators. In vitro assays were performed primarily with M-CSF plus IL-10 driven monocyte-derived M2c macrophages from healthy donors. Ex vivo assays were performed with fresh, patient-derived tumor samples in culture. To determine whether targeting VSIG4 can lead to an anti-tumor effect in vivo, syngeneic mouse models were dosed with anti-mouse VSIG4 antibodies and characterized for changes in tumor volume and immune cell populations.

Results

In in vitro and ex vivo assays anti-VSIG4 antibodies repolarize M2 macrophages and induce an immune response culminating in T cell activation. Targeting VSIG4 upregulates pro-inflammatory cytokines in M2c macrophages, as well as upregulates pro-inflammatory myeloid-derived cytokines and T cell-derived cytokines in M2c macrophages co-cultured with autologous T cells in the presence of staphylococcal enterotoxin B (SEB) activation. To assess targeting VSIG4 in a relevant translational model, fresh, patient-derived tumor samples were treated ex vivo with anti-VSIG4. Across multiple tumor types, anti-VSIG4 treatment resulted in a significant upregulation of cytokines involved in TAM repolarization and T cell activation, and chemokines involved in immune cell recruitment, at levels greater than observed by treatment with anti-PD-1 or a clinical macrophage repolarizing agent (anti-ILT-4). In vivo, tumor growth inhibition is observed in syngeneic mouse models dosed with anti-mouse-VSIG4 alone and in combination with anti-PD-1.

Conclusions

Taken together, these data suggest that VSIG4 represents a promising new target capable of stimulating an anti-cancer response via multiple key immune mechanisms.

References

van Lookeren Campagne M, Verschoor A. Pathogen clearance and immune adherence “revisited”: immuno-regulatory roles for CRIg. Semin Immunol 2018;37:4–11.

Xu S, Sun Z, Li L, Liu J, He J, Song D, Shan G, Liu H, Wu X. Induction of T cells suppression by dendritic cells transfected with VSIG4 recombinant adenovirus. Immunol Lett 2010;128(1):46–50.

Liao Y, Guo S, Chen Y, Cao D, Xu H, Yang C, Fei L, Ni B, Ruan Z. VSIG4 expression on macrophages facilitates lung cancer development. Lab Invest 2014;94(7):706–715.

Roh J, Jeon Y, Lee A, Lee S, Kim Y, Sung C, Park C, Hong J, Yoon D, Suh C, Huh J, Choi I, Park C. The immune checkpoint molecule V-set Ig domain-containing 4 is an independent prognostic factor for multiple myeloma. Oncotarget 2017;8(35):58122–58132.

Xu T, Jiang Y, Yan Y, Wang H, Lu C, Xu H, Li W, Fu D, Lu Y, Chen J. VSIG4 is highly expressed and correlated with poor prognosis of high-grade glioma patients. Am J Transl Res 2015;7(6):1172–1180.

Byun J, Jeong D, Choi I, Lee D, Kang M, Jung K, Jeon Y, Kim Y, Jung E, Lee K, Sung M, Kim K. The significance of VSIG4 expression in ovarian cancer. Int J Gynecol Cancer 2017;27(5):872–878.

Ethics Approval

All legal and ethical requirements were met with regards to the humane treatment of animals described in the study. The animal study was conducted in compliance with CRL IACUC under IACUC No. I033.

877 PSGL-1 blocking antibodies repolarize tumor associated macrophages, reduce suppressive myeloid populations and induce inflammation in the tumor microenvironment, leading to suppression of tumor growth

Background

Suppressive myeloid cell populations in the tumor microenvironment (TME) are associated with worse survival of cancer patients and low effectiveness of T cell checkpoint inhibitors. Recently, several early clinical trials have produced positive data for therapies aimed at repolarizing immuno-suppressive myeloid populations in the TME. One new macrophage repolarizing target, PSGL-1 (P-selectin glycoprotein ligand-1), is expressed at high levels on suppressive tumor-associated macrophages (TAMs) and in vitro differentiated M2 macrophages. PSGL-1 has been shown to have an immune-modulatory activity, which includes its role in maintaining an immuno-suppressive macrophage state.

Methods

To assess the ability of PSGL-1 antibodies to convert macrophages and the tumor microenvironment from an immuno-suppressive toward a pro-inflammatory state, we employed in vitro primary macrophage and multi-cellular assays, ex vivo patient-derived tumor cultures, and a humanized mouse PDX model.

Results

We have determined that our lead anti-PSGL-1 antibody repolarized M2-like macrophages to a more M1-like state both phenotypically and functionally as assessed in primary in vitro macrophage assays. Transcriptomics profiling of M2c macrophages showed that the anti-PSGL-1 antibody upregulated TNF-alpha/NF-kB and chemokine-mediated signaling, while downregulating oxidative phosphorylation, fatty acid metabolism and Myc signaling pathways, consistent with a broad M2-to-M1 shift of the macrophage state. Furthermore, these repolarized M1-like macrophages enhanced the inflammatory response in complex multi-cellular assays.Pre-clinical efficacy of the anti-PSGL-1 antibody was demonstrated using ex vivo cultures of fresh patient-derived tumors that preserve the cellular heterogeneity of the TME. Anti-PSGL-1 increased production of inflammatory cytokines and chemokines involved in immune activation of the TME and T cell recruitment.Lastly, our lead anti-PSGL-1 antibody also showed in vivo anti-tumor effect in a humanized mouse PDX model of melanoma. The antibody suppressed tumor growth to a significantly greater degree compared to anti-PD-1. At the cellular and molecular levels, the anti-PSGL-1 treatment led to a more enhanced inflammatory microenvironment, including a reduced M2:M1 macrophage ratio, and an increase in systemic pro-inflammatory mediators. Compared to anti-PD-1 monotherapy, anti-PSGL-1 alone and in combination with anti-PD-1 increased the fraction of effector CD8+ T cells among the infiltrating T cells. Significant combination effects of anti-PSGL-1 plus anti-PD-1 were seen at the cellular and molecular levels within the tumor tissue, the spleen, and peripheral blood.

Conclusions

The data presented here provide biological and mechanistic support for clinical testing of antibodies targeting PSGL-1 for the treatment of cancer.

Ethics Approval

All legal and ethical requirements were met with regards to the humane treatment of animals described in the study. The animal study was conducted in compliance with IACUC PROTO202000042 and the institutional assurance certification of the University of Massachusetts Medical School. The University of Massachusetts Medical School is fully accredited by AAALAC and has an Animal Welfare Assurance on file with the Office of Laboratory Animal Welfare (OLAW).

Economic evaluations of public health interventions for physical activity and diet: systematic review

Background

Physical inactivity and unhealthy dietary habits are associated with an increased disease and economic burden. Despite the prevalence of different public health programs, decision-makers encounter a multitude of challenges in prioritizing interventions for optimal resource allocation. The aim of this systematic review, therefore, was to identify economic evaluations of public health interventions targeting physical activity and healthy diet, and assess the quality and transferability of the findings to the Swedish context.

Methods

A search of published economic evaluations was conducted through electronic databases including PubMed, Web of Science, PsycINFO, National Health Service Economic Evaluation Databases (NHS EED) and the Health Technology Assessment Database (HTA). An additional search was done using references of relevant systematic reviews and, websites of relevant organizations were checked to find grey literature. Quality and transferability of the economic evaluations were appraised using a quality assessment tool developed by the Swedish Agency for Health Technology Assessment.

Preliminary Results

Thirty-two economic evaluations of 178 interventions were included; thirteen studies targeting physical activity, thirteen targeting healthy diet and six targeting both. The interventions varied in terms of their content, setting, mode of delivery and target populations. A majority of the economic evaluations reported that the interventions were likely to be cost-effective; however, considerable variations in the methodological and reporting qualities were observed. Only half of the economic evaluations were rated to have a high probability of transferring to the Swedish context.

Conclusions

Most of the interventions were reported to be cost-effective. However, a variation in quality and transferability of the available evidence to the Swedish context were observed.

Key messages

Public health interventions targeting physical activity and dietary habits have a high potential to be cost-effective. Decision makers should consider transferability and suitability of findings of economic evaluation from a different context to a decision problem at hand.

Economic evaluations of public health interventions for mental health: A systematic literature review

Background

To review the literature on economic evaluations of public health interventions targeting prevention of mental health problems and suicide, to support evidence based societal resource allocation.

Methods

A systematic review of economic evaluations within mental health and suicide prevention was conducted including studies published between 2000 and 2018. The studies were identified through Medline, PsychINFO, Web of Science. The quality of relevant studies and the transferability of their results were assessed using a criterion set out by the Swedish Agency for Health Technology Assessment.

Results

Nineteen studies of moderate to high quality were included in this review, which evaluated 18 interventions in mental health and 4 interventions in suicide prevention. Fourteen (63%) of all interventions were cost-effective. None of the studies that evaluated suicide prevention was of high quality. The interventions largely focused on psychological interventions at school, the workplace and within elderly care as well as screening and brief interventions in primary care. Nine studies (around 50% of included articles) had a high potential for transferability to the Swedish context.

Conclusions

Public health interventions aiming to improve mental health have a high potential to be economically beneficial to society, but high-quality evidence on the cost-effectiveness of suicide prevention is limited.

Key messages

Public health interventions aiming to improve mental health have a high potential to be economically beneficial to society. Evidence on the cost-effectiveness of suicide prevention is limited.

Cost-effectiveness of an indicated preventive intervention for depression in adolescents

Background

Adolescent depression has negative health and economic outcomes in the short- and long-term. Indicated preventive interventions, in particular group based cognitive behavioural therapy (GB-CBT), are effective in preventing depression in adolescents with subsyndromal depression. However, little is known about the cost-effectiveness of these interventions.

Methods

A Markov cohort model was used to conduct cost-effectiveness analyses comparing a GB-CBT indicated preventive intervention for depression, to a no-intervention option. Taking a time horizon of 5- and 10 years, incremental differences in societal costs and health benefits expressed as cases of depression prevented, and as quality adjusted life years (QALYs) gained were estimated. Through univariate and probabilistic sensitivity analyses, the robustness of the results was explored. Costs, presented in 2018 USD, and effects were discounted at a yearly rate of 3%.

Results

The base-case analysis showed that GB-CBT indicated preventive intervention incurred lower costs, prevented more cases of depression and generated higher QALYs compared to the no-intervention option for both time horizons. Offering the intervention was even a cost saving strategy and demonstrated a probability of being cost-effective of over 95%. In the sensitivity analyses, these results were robust to the modelling assumptions. Limitations: The study considered a homogeneous cohort and assumed a constant annual decay rate of the relative treatment effect.

Conclusions

GB-CBT indicated preventive interventions for depression in adolescence can generate good value for money compared to leaving adolescents with subsyndromal depression untreated.

Key messages

Indicated preventive interventions for depression are cost-saving and can generate substantial health benefits. Indicated preventive interventions can be adopted as cost-effective preventive strategies for depression.

Effectiveness of a school-based intervention for adolescents and teachers to promote mental health among refugee and migrant adolescents

Refugee youth have often experienced trauma during relocation and continue to face adversity in their host country in the form of acculturation stress, residence insecurity, social isolation, and experiences of discrimination. These experiences are associated with a significant risk of developing mental health problems such as post-traumatic stress disorder (PTSD). This cluster randomised trial aims to evaluate the effectiveness of a school-based intervention that provides a manualized, trauma-focussed programme called Teaching Recovery Techniques (TRT) to target refugee and migrant youth and an In-Service Teacher Training (INSETT) programme to teachers. The study will consider the impact of the intervention on the mental health of adolescent refugees and their guardians who participate in the TRT programme. It will also consider the intervention's impact on the interrelationships between teachers and parents and teachers' cultural competence, as well as the social support and school belonging experienced by adolescents who do not participate in TRT but whose teachers receive INSETT training. Further details on TRT and INSETT, trial design and preliminary findings will be presented at the workshop.

PSGL-1 is a novel macrophage checkpoint in immuno-oncology

e15090

Background: Macrophages are both antigen presenting and effector cells of the innate immune system and play an important role in tissue homeostasis as well as in activation and modulation of the adaptive immune response in disease. They display phenotypic heterogeneity in different tissue environments but can be broadly subdivided into pro-inflammatory M1 macrophages, which promote immune response, and anti-inflammatory M2 macrophages, which are associated with immune suppression. Under steady-state conditions, the populations of immune-stimulatory and immune-regulatory macrophages are balanced, but disruption of this balance can result in disease. In the tumor microenvironment, tumor-associated macrophages (TAMs) acquire an M2-like phenotype and maintain suppression of the immune system and promotion of tumor progression. Methods: For functional screening of anti-PSGL-1 antibodies, monocytes were isolated from peripheral blood mononuclear cells (PBMC) obtained from healthy donors and differentiated into M2 macrophages in the presence or absence of anti-PSGL-1 antibodies. On day 8 of the assay, phenotypic profile of cells was analyzed by flow cytometry and chemokines / cytokines were measured by Luminex. Mixed-lymphocyte reaction assay, SEB assay and an ex vivo tumor model were used to further assess antibody functionality in a multi-cellular assay format. For T cell assays, purified T cells from PBMC were stimulated in the presence or absence of anti-PSGL-1 antibodies and responses were characterized by flow cytometry and Luminex. Results: We have identified PSGL-1 as a novel macrophage checkpoint. Our work demonstrates that targeting PSGL-1 via an antagonistic antibody re-polarizes human primary M2 macrophages to a more M1-like state both phenotypically and functionally. We observe this M2-to-M1 switch to have an impact on immune cell communication in complex multi-cellular assays. Moreover, targeting of PSGL-1 in an ex vivo tumor system demonstrates that anti-PSGL-1 treatment can increase pro-inflammatory cytokine and chemokine production known to be associated with beneficial clinical response. These effects can be predominantly attributed to macrophage modulation, as antibody targeting PSGL-1 on purified T cells has a very small, if any, impact on their activation and effector function. Conclusions: Our results demonstrate that treatments inducing macrophage phenotypic switches can promote an immune response in a tumor setting across multiple tumor types and provide support for targeting the novel macrophage checkpoint PSGL-1 across multiple cancer indications.

The equity impact of a universal child health promotion programme

Background

We aimed to evaluate whether the Salut Programme, a universal child health promotion intervention, aimed to strengthen healthy lifestyles in northern Sweden, had any effect on income-related inequalities in positive birth outcomes for children and on healthcare use for children and their mothers.

Methods

Mother’s residence and child’s date of birth determined whether the child and the mother belonged to the control group (areas that received care-as-usual) or the intervention group (areas with the intervention implemented from 2005), during the pre-measure period (children born 2002-2004) and the post-measure period (children born 2006-2008). The sum of parents’ taxable income was used for socioeconomic ranking. We computed the standard concentration index for six binary indicators of positive birth outcomes, and for inpatient and day patient care for children and mothers during the two years after delivery. Using a difference-in-difference approach, we assessed whether the extent of inequality changed over time between areas.

Results

Income-related inequalities in child health status at birth and in child healthcare use were absent, except that full-term pregnancies were concentrated among the poor at pre-measure in the intervention group. However, mothers’ healthcare use was significantly pro-poor in the control group. The extent of inequality changed between pre- and post-measure periods for two outcomes: the pro-poor concentration of full-term pregnancies in the intervention group at pre-measure disappeared at post-measure; and an increase in pro-poor concentration of normal birth weight in the control group was not matched by a similar increase in the intervention group. Inequalities in healthcare use did not change significantly.

Conclusions

Birth outcomes and child healthcare use seemed to be equitably distributed. However, the results raise concerns whether the intervention may have reduced the pro-poor concentration of positive birth outcomes.

Key messages

There are concerns that participation in universal health promotion programmes differs by socioeconomic status, although few public health interventions have been evaluated from an equity perspective. Birth outcomes and child healthcare use in Northern Sweden seemed to be equitably distributed across different socioeconomic groups.

How Artificial Intelligence Can Improve Our Understanding of the Genes Associated with Endometriosis: Natural Language Processing of the PubMed Database

Endometriosis is a disease characterized by the development of endometrial tissue outside the uterus, but its cause remains largely unknown. Numerous genes have been studied and proposed to help explain its pathogenesis. However, the large number of these candidate genes has made functional validation through experimental methodologies nearly impossible. Computational methods could provide a useful alternative for prioritizing those most likely to be susceptibility genes. Using artificial intelligence applied to text mining, this study analyzed the genes involved in the pathogenesis, development, and progression of endometriosis. The data extraction by text mining of the endometriosis-related genes in the PubMed database was based on natural language processing, and the data were filtered to remove false positives. Using data from the text mining and gene network information as input for the web-based tool, 15,207 endometriosis-related genes were ranked according to their score in the database. Characterization of the filtered gene set through gene ontology, pathway, and network analysis provided information about the numerous mechanisms hypothesized to be responsible for the establishment of ectopic endometrial tissue, as well as the migration, implantation, survival, and proliferation of ectopic endometrial cells. Finally, the human genome was scanned through various databases using filtered genes as a seed to determine novel genes that might also be involved in the pathogenesis of endometriosis but which have not yet been characterized. These genes could be promising candidates to serve as useful diagnostic biomarkers and therapeutic targets in the management of endometriosis.

Abstract 406: CRISPR pooled screening of hundreds of cancer cell lines identifies differential dependencies on epigenetic pathways and synthetic lethal relationships

Target identification is a critical step in drug discovery, but the process has many challenges including non-specific reagents, limited ability to test numerous models, and incomplete target inhibition. Pooled screening with CRISPR/Cas9 permits the quick and accurate examination of proliferation effects across many genes and many cell lines. To determine the specific dependencies of cell lines on epigenetic pathways, we designed a CRISPR/Cas9 library to target 640 epigenetic genes and screened more than 200 cell lines covering a variety of oncology indications, including breast, lung, and renal cell carcinoma (RCC). We find that CRISPR pooled screening is a highly effective approach for target identification and provides robust, highly reproducible data as long as a sufficient number of small guide RNAs are used. We identify known pan-essential genes, including in the transcription (CDK9), translation (EIF4A1 and EIF4A3) and splicing (SRSF2) machinery. We additionally identify many novel pan-essential genes across a variety of epigenetic pathways, including histone acetylases and deacetylases, chromatin remodeling factors, helicases and others. We also investigated epigenetic synthetic lethal interactions that have been previously reported. For example, it has been reported that the SWI/SNF family displays paralog synthetic lethality for SMARCA2 in the context of SMARCA4 mutations, and for ARID1B in the context of ARID1A mutations. While we do see that some of the same trends hold, the synthetic lethal relationship appears to be more complex than previously realized, including the need to examine mRNA levels in addition to mutation type. Most importantly, we identify more than 100 epigenetic genes which show selective sensitivity, i.e. where knockout shows an anti-proliferative effect in only a subset of the cell lines. These are the most promising targets for further drug discovery programs. We have used additionally CRISPR/Cas9-domain based screening to identify the functionally relevant sites for many of these genes. Furthermore, we can overlay gene expression and mutation data to identify novel synthetic lethal relationships. One gene that displays selective sensitivity is EGLN1, the prolyl hydroxylase for the hypoxia-inducible factor, HIF1α. We find that EGLN1 is required for proliferation only in RCC cell lines which retain wild-type VHL, another component of the hypoxia response pathway, which is frequently lost in RCC. As such, EGLN1 loss is synthetically lethal in the presence of wild-type VHL in RCC cells. Thus this approach not only identifies an enzymatic drug target but also a patient stratification method. Other novel synthetic lethal interactions have also been identified. Our data demonstrates that CRISPR pooled screening is a powerful technique for identification of epigenetic synthetic lethal interactions.

Citation Format: Alexandra R. Grassian, Darren Harvey, Julian Fowler, Allison E. Drew, Igor Feldman, Richard Chesworth, Robert Copeland, Jesse J. Smith, Scott Ribich. CRISPR pooled screening of hundreds of cancer cell lines identifies differential dependencies on epigenetic pathways and synthetic lethal relationships [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 406. doi:10.1158/1538-7445.AM2017-406

Abstract 3345: Selective killing of SMARCA2- and SMARCA4-deficient tumors by inhibition of EZH2: In vitro and in vivo preclinical models

The histone methyltransferase EZH2 is the enzymatic subunit of the polycomb repressive complex 2 (PRC2) that catalyzes the methylation of H3K27 thereby repressing target gene transcription. EZH2 is amplified, overexpressed, or mutated in multiple cancer types, most notably Follicular Lymphoma (FL) and germinal center Diffuse Large B-cell Lymphoma (GCB-DLBCL). We previously reported that preclinical models of malignant rhabdoid tumors, which are deficient in the SWI/SNF core component INI1 (SNF5, SMARCB1), are selectively killed by potent and selective inhibitors of EZH2. Here we report another class of SWI/SNF-altered cancers named small cell carcinoma of the ovary hypercalcemic type (SCCOHT) that is dependent on EZH2 activity. SCCOHT is a very aggressive form of cancer that responds poorly to conventional therapy with a one-year overall survival rate of only 50%. Very few novel agents have been approved for this indication; thus there is a need for targeted therapeutics in SCCOHT. SMARCA4 and SMARCA2 are co-inactivated in this tumor type that has many rhabdoid features. We demonstrate that tazemetostat, an EZH2 inhibitor currently in phase 2 clinical trials, induces potent and selective killing in SMARCA2 and SMARCA4-deficient ovarian cell lines. In addition to small molecule inhibitor data, we conducted functional genomics studies with CRISPR pooled screening, and confirmed that SCCOHT is also sensitive to CRISPR-mediated EZH2 gene ablation. Dose-dependent anti-tumor effects were observed upon tazemetostat treatment in SCCOHT xenografts deficient in both SMARCA2 and SMARCA4. We also report on additional non-ovarian tumor types with dual SMARCA2/SMARCA4 loss including NSCLC that exhibit EZH2 dependence representing additional potential therapeutic indications for tazemetostat treatment.

Citation Format: Elayne Chan-Penebre, Kelli Armstrong, Allison Drew, Alexandra R. Grassian, Igor Feldman, Maria Roche, Peter Ho, Dorothy Brach, Alejandra Raimondi, Robert A. Copeland, Richard Chesworth, Jesse J. Smith, Scott A. Ribich. Selective killing of SMARCA2- and SMARCA4-deficient tumors by inhibition of EZH2: In vitro and in vivo preclinical models [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 3345. doi:10.1158/1538-7445.AM2017-3345

Selective Killing of SMARCA2- and SMARCA4-deficient Small Cell Carcinoma of the Ovary, Hypercalcemic Type Cells by Inhibition of EZH2: In Vitro and In Vivo Preclinical Models

The SWI/SNF complex is a major regulator of gene expression and is increasingly thought to play an important role in human cancer, as evidenced by the high frequency of subunit mutations across virtually all cancer types. We previously reported that in preclinical models, malignant rhabdoid tumors, which are deficient in the SWI/SNF core component INI1 (SMARCB1), are selectively killed by inhibitors of the H3K27 histone methyltransferase EZH2. Given the demonstrated antagonistic activities of the SWI/SNF complex and the EZH2-containing PRC2 complex, we investigated whether additional cancers with SWI/SNF mutations are sensitive to selective EZH2 inhibition. It has been recently reported that ovarian cancers with dual loss of the redundant SWI/SNF components SMARCA4 and SMARCA2 are characteristic of a rare rhabdoid-like subtype known as small-cell carcinoma of the ovary hypercalcemic type (SCCOHT). Here, we provide evidence that a subset of commonly used ovarian carcinoma cell lines were misdiagnosed and instead were derived from a SCCOHT tumor. We also demonstrate that tazemetostat, a potent and selective EZH2 inhibitor currently in phase II clinical trials, induces potent antiproliferative and antitumor effects in SCCOHT cell lines and xenografts deficient in both SMARCA2 and SMARCA4. These results exemplify an additional class of rhabdoid-like tumors that are dependent on EZH2 activity for survival. Mol Cancer Ther; 16(5); 850-60. ©2017 AACR.

Abstract 586: Discovery of a novel TIM3 binding partner and a key role for TIM3 on macrophages: Identification of specific antibodies capable of converting immune-suppressive macrophages to immune-enhancing

Our Translational Science Platform uses an unbiased bioinformatics-based approach to interrogate particular cell types within the tumor microenvironment (TME). Given the correlation between high levels of immune-suppressive macrophages within the tumor TME and poor patient prognosis across a number of solid tumor types we focused initially on developing novel immunotherapies to modify this cell type. We identified 10 targets as candidates for converting tumor-associated macrophages from immune-suppressing to immune-enhancing.

One of these targets was TIM3. To date, TIM3 has been pursued mainly as a checkpoint target for T cell-directed immunotherapies based on its expression on exhausted T cells. Anti-TIM3 mAbs, generated by multiple groups, induce responsiveness in T cells and demonstrate anti-tumor benefit in certain mouse models. However, our macrophage-centric approach has identified a previously unrecognized protein-protein interaction between TIM3 and one of our additional macrophage targets. Based on knowledge of this interaction, we were able to generate and select for panels of mAbs to TIM3 and to its binding partner capable of converting macrophages from an “M2” to an “M1” pro-inflammatory phenotype.

In contrast to published anti-TIM3 mAbs, our particular anti-TIM3 mAbs lacked activity in T cell-based assays, but promoted an increase in pro-inflammatory cytokines with a reduction or no effect in anti-inflammatory cytokines in a macrophage activity assay. In this assay, monocytes were prepared from human peripheral blood and cultured in the presence of M-CSF to bias toward an M2 phenotype. Under sub-optimal stimulation with LPS or CD40L or HMGB1, treatment of these cells with the anti-TIM3 mAbs led to increases in pro-inflammatory cytokines including IL-1β and TNFα.

The conversion to an “M1” macrophage by anti-TIM3 mAbs had downstream consequences on T cells as demonstrated by mixed lymphocyte reaction experiments. In these studies, the addition of anti-TIM3 led to a macrophage-dependent increase in IFNγ from the T cells. To assess the impact of our anti-TIM3 mAbs in the tumor setting, tumor histoculture experiments were performed. Tumor tissue slices from ovarian cancer patients treated with anti-TIM3 showed an increase in a range of cytokines and in this tumor setting the initial sub-optimal stimulus was not required.

Specific antibodies to TIM3 and its binding partner that are able to promote a pro-inflammatory macrophage phenotype have been generated. We are developing these as modulators of the TME, to be assessed either as single agents or in combination with other therapies such as checkpoint inhibitors.

Citation Format: Jamie Wong, Ryan Phennicie, Igor Feldman, Sriram Sathyanarayanan, Don Shaffer, Mohammad Zafari, Steve Sazinsky, Kenneth Crook, Debbie Law. Discovery of a novel TIM3 binding partner and a key role for TIM3 on macrophages: Identification of specific antibodies capable of converting immune-suppressive macrophages to immune-enhancing. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 586.

An Unbiased Oncology Compound Screen to Identify Novel Combination Strategies

Combination drug therapy is a widely used paradigm for managing numerous human malignancies. In cancer treatment, additive and/or synergistic drug combinations can convert weakly efficacious monotherapies into regimens that produce robust antitumor activity. This can be explained in part through pathway interdependencies that are critical for cancer cell proliferation and survival. However, identification of the various interdependencies is difficult due to the complex molecular circuitry that underlies tumor development and progression. Here, we present a high-throughput platform that allows for an unbiased identification of synergistic and efficacious drug combinations. In a screen of 22,737 experiments of 583 doublet combinations in 39 diverse cancer cell lines using a 4 by 4 dosing regimen, both well-known and novel synergistic and efficacious combinations were identified. Here, we present an example of one such novel combination, a Wee1 inhibitor (AZD1775) and an mTOR inhibitor (ridaforolimus), and demonstrate that the combination potently and synergistically inhibits cancer cell growth in vitro and in vivo This approach has identified novel combinations that would be difficult to reliably predict based purely on our current understanding of cancer cell biology. Mol Cancer Ther; 15(6); 1155-62. ©2016 AACR.

Abstract P2-11-07: Mutually exclusive expression pattern of the immune co-inhibitory molecules B7-H4 and PD-L1 in triple negative breast cancer

B7-H4 (VTCN1, B7x, B7S1) is a transmembrane protein belonging to the B7 family of costimulatory proteins and has been shown to inhibit T cell proliferation, cytokine secretion, and cytotoxic lymphocyte (CTL) induction. B7-H4 expressed on tumor cells or macrophages has been associated with poor prognosis and impaired T cell function in renal cell and ovarian cancers. Here we show B7-H4 is abundantly expressed in human breast cancer with triple negative breast cancer (TNBC) having the highest overall B7-H4 mRNA expression. We developed a specific and sensitive immunohistochemistry (IHC) assay for evaluation of B7-H4 protein and quantified B7-H4 expression in 156 breast tumor samples. Approximately 70% of the breast tumor samples had detectable B7-H4 expression whereas none of the normal or benign breast tissues stained positive for B7-H4. Multiplex IHC and flow cytometry studies showed that the majority of B7-H4 expression was restricted to the tumor epithelial cells, the CD45+ immune cells were negative for B7-H4 expression. Interestingly none of the TNBC samples that were positive for B7-H4 showed detectable expression of PD-L1 suggesting that B7-H4 and PD-L1 checkpoint proteins may act in a mutually exclusive manner.

To evaluate the role of B7-H4 on tumor immune evasion, we overexpressed murine or human B7-H4 on the mouse colon-26 (CT26) tumor cell line and injected these cells intravenously into Balb/c mice. By day 14 we observed significantly more tumors as well as larger percent tumor area in the lungs of mice given CT26 cells transduced with human or mouse B7-H4 as compared to vector control transduced cells. These data suggest B7-H4 expression in tumors can accelerate tumor growth in immune competent mice and that targeting B7-H4 may provide therapeutic benefit. Given the mutually exclusive expression patterns of B7-H4 and PD-L1 a B7-H4 targeting agent may provide particular benefit in those patients where current anti-PD-1/PD-L1 therapies are not effective.

Citation Format: Shaffer DR, Nagashima K, Cortez-Retamozo V, Feldman I, Smith J, Zafari M, Larson R, Mabry R, Novorantseva T, Briskin M, Sathyanaryananan S. Mutually exclusive expression pattern of the immune co-inhibitory molecules B7-H4 and PD-L1 in triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-11-07.

Abstract B78: CRISPR pooled screening identifies differential dependencies on epigenetic pathways

It has become clear in the past decade that dysregulation of epigenetic pathways is fundamental to many if not all tumors. Importantly, a number of epigenetic targeted therapies are now being tested in the clinic and are beginning to show promising efficacy. Identification of new targets for oncology therapeutics is critical, and the ideal target should: 1) be effective in a specific indication or genetically defined patient population; and 2) lead to a minimal amount of deleterious side effects in patients. Thus, target identification must be performed in a large number of cell lines to address both objectives and to ensure specific target dependence. However, it remains challenging to identify specific dependencies on epigenetic genes in preclinical models, which may result in part from the need for near complete loss of protein function for this class of enzymes to observe proliferation phenotypes, and this can be difficult to achieve with RNAi reagents. The advent of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology enables the specific and complete knockout of the target protein and allows for observation of proliferation phenotypes that RNAi studies may not uncover. Additionally, the CRISPR-Cas9 system is amenable to pooled cell line screening which permits the quick and accurate examination of proliferation effects across many genes and many cell lines.

To examine the specific dependencies of cell lines on epigenetic pathways, we have used pooled CRISPR-Cas9 screening to interrogate over 600 epigenetic-related genes in a panel of more than 60 cells lines. The performance of the screen is highly consistent and able to reproduce findings that have been previously reported. We observe that CRISPR pooled screening is highly effective at identifying targets which are known to be required for cell proliferation either in all cell lines or in a genetically-defined subset of cell lines. We also identify new epigenetic-related genes required for the proliferation of almost all the cell lines tested, and have termed these “pan-essential” epigenetic genes. Intriguingly, these pan-essential genes represent members of almost all classes of epigenetic pathways, including histone methyltransferases, histone acetylases and deacetylases, chromatin remodeling factors, regulators of mRNA splicing, DNA helicases and others. This is an important set of genes to identify, as they represent targets which are likely to induce broad clinical toxicity if inhibited in patients, yet may be identified as potential targets in pre-clinical interrogation which does not fully examine proliferation dependencies in a sufficiently broad panel of cell lines.

Importantly, we also identify a variety of epigenetic targets which induce altered proliferation in a subset of cell lines tested. These include epigenetic-related genes from many classes, including histone methyltransferases. Notably, for certain genes, trends are emerging that indicate a specific genetic marker(s) which may predict dependence on these epigenetic targets. These genes represent highly promising targets for epigenetic therapeutics in a variety of oncology indications.

Citation Format: Alexandra R. Grassian, Julian Fowler, Igor Feldman, Thomas Riera, Darren Harvey, Allison E. Drew, Richard Chesworth, Robert A. Copeland, Heike Keilhack, Jesse J. Smith, Scott Ribich. CRISPR pooled screening identifies differential dependencies on epigenetic pathways. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B78.

Preclinical evaluation of the WEE1 inhibitor MK-1775 as single-agent anticancer therapy

Inhibition of the DNA damage checkpoint kinase WEE1 potentiates genotoxic chemotherapies by abrogating cell-cycle arrest and proper DNA repair. However, WEE1 is also essential for unperturbed cell division in the absence of extrinsic insult. Here, we investigate the anticancer potential of a WEE1 inhibitor, independent of chemotherapy, and explore a possible cellular context underlying sensitivity to WEE1 inhibition. We show that MK-1775, a potent and selective ATP-competitive inhibitor of WEE1, is cytotoxic across a broad panel of tumor cell lines and induces DNA double-strand breaks. MK-1775-induced DNA damage occurs without added chemotherapy or radiation in S-phase cells and relies on active DNA replication. At tolerated doses, MK-1775 treatment leads to xenograft tumor growth inhibition or regression. To begin addressing potential response markers for MK-1775 monotherapy, we focused on PKMYT1, a kinase functionally related to WEE1. Knockdown of PKMYT1 lowers the EC(50) of MK-1775 by five-fold but has no effect on the cell-based response to other cytotoxic drugs. In addition, knockdown of PKMYT1 increases markers of DNA damage, γH2AX and pCHK1(S345), induced by MK-1775. In a post hoc analysis of 305 cell lines treated with MK-1775, we found that expression of PKMYT1 was below average in 73% of the 33 most sensitive cell lines. Our findings provide rationale for WEE1 inhibition as a potent anticancer therapy independent of a genotoxic partner and suggest that low PKMYT1 expression could serve as an enrichment biomarker for MK-1775 sensitivity.

Abstract 4931: Biomarker discovery in a large panel of cell lines shows different sample size requirement for prediction of response across a set of compounds

A panel of more than 600 cell lines from 17 tumor types has been profiled and sensitivity to a set of FDA approved compounds with different mechanisms of action has been tested. Comparison of gene expression profiles with overlapping set of publicly available profiles showed 100% accuracy of cell line identity prediction using nearest neighbor classifier. Similar analysis of CNV data had 80% accuracy due to relatively little CNV perturbation in some of the cell lines. Significant gene expression signatures have been detected for 80% of compounds. De-novo agnostic classification based on 50% train/test split and a linear classifier resulted in significant prediction on the test set for about 40% of the compounds, such as dasatinib, 5FU, paclitaxel, but failed to produce a significant prediction for others, such as doxorubicine, irinotecan, and vinblastine. For most of the compounds, the prediction of response is complex, with multiple distinct molecular features contributing to a classification algorithm. This inherent complexity requires integration of gene expression, CNV and mutation data as well as a large cell line sets for development of accurate classification algorithms. We defined functional CNV and SNV events using gene expression based modules as a functional readout. Predictive models that incorporate prior knowledge of mechanism of action of the compounds and rely on functional SNV and CNV events out perform completely agnostic methods of prediction.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4931. doi:1538-7445.AM2012-4931

Pathway-based identification of biomarkers for targeted therapeutics: personalized oncology with PI3K pathway inhibitors

Although we have made great progress in understanding the complex genetic alterations that underlie human cancer, it has proven difficult to identify which molecularly targeted therapeutics will benefit which patients. Drug-specific modulation of oncogenic signaling pathways in specific patient subpopulations can predict responsiveness to targeted therapy. Here, we report a pathway-based phosphoprofiling approach to identify and quantify clinically relevant, drug-specific biomarkers for phosphatidylinositol 3-kinase (PI3K) pathway inhibitors that target AKT, phosphoinositide-dependent kinase 1 (PDK1), and PI3K-mammalian target of rapamycin (mTOR). We quantified 375 nonredundant PI3K pathway-relevant phosphopeptides, all containing AKT, PDK1, or mitogen-activated protein kinase substrate recognition motifs. Of these phosphopeptides, 71 were drug-regulated, 11 of them by all three inhibitors. Drug-modulated phosphoproteins were enriched for involvement in cytoskeletal reorganization (filamin, stathmin, dynamin, PAK4, and PTPN14), vesicle transport (LARP1, VPS13D, and SLC20A1), and protein translation (S6RP and PRAS40). We then generated phosphospecific antibodies against selected, drug-regulated phosphorylation sites that would be suitable as biomarker tools for PI3K pathway inhibitors. As proof of concept, we show clinical translation feasibility for an antibody against phospho-PRAS40(Thr246). Evaluation of binding of this antibody in human cancer cell lines, a PTEN (phosphatase and tensin homolog deleted from chromosome 10)-deficient mouse prostate tumor model, and triple-negative breast tumor tissues showed that phospho-PRAS40(Thr246) positively correlates with PI3K pathway activation and predicts AKT inhibitor sensitivity. In contrast to phosphorylation of AKT(Thr308), the phospho-PRAS40(Thr246) epitope is highly stable in tissue samples and thus is ideal for immunohistochemistry. In summary, our study illustrates a rational approach for discovery of drug-specific biomarkers toward development of patient-tailored treatments.

Abstract PR3: Preclinical and molecular profiling data suggest LumB breast cancer as a potential indication for co-targeting IGF1R and mTOR with MK-0646 and MK-8669

There has been increasing interest in developing cancer therapies targeting PI3K pathway nodes. However, inhibition of a single node in PI3K pathway such as mTOR by rapamycin analogues results in compensatory activation of survival signaling pathway such as AKT and thereby limiting monotherapy activity. Therefore, in most tumor types, multipathway inhibition, guided by an in-depth understanding of feedback and crosstalk between pathways, may be required for tumor regression. It is well known that that mTOR inhibition upregulates pAKT via the S6K-IRS2 negative feedback loop. Inhibiting both mTOR and IGF1R may therefore ablate such feedback upregulation and lead to clinical response. However, it is unclear which tumor types will respond to the combination in the clinic. Here, we present preclinical and molecular profiling data that supports LumB breast cancer as a potential indication for MK-8669/MK-0646 (mTOR/IGF1 R inhibitor combination). When a panel of over 60 breast cancer cell lines was treated with MK-8669, ER+ cell lines and HER2+ cell lines were clearly more responsive than the triple negative ones. Meanwhile, the status of the MAPK pathway, as captured by a RAS gene expression signature, correlated with resistance to MK-8669 across the panel. Moreover, MK-8669 treatment unregulated multiple key nodes of the IGF1R pathway in the breast cell line panel, especially IRS2, whose upregulation correlated with the response to MK-8669. Furthermore, IGF1R, whose mRNA level correlates with the response to MK-0646 (IGF1 Ri) in multiple internal and external studies, is the highest in a subset of LumB tumors, suggesting a potential dependency on the IGF1R pathway in those tumors. Finally, a comparison between the gene expression profiles of breast cancer cell lines and tumors revealed that the ER+ breast cancer cell lines only represented the LumB, not LumA, subtype of human breast tumors. Taken together, these findings allow us to hypothesize that LumB breast cancer may be enriched in responders to the MK-0646/MK-8669 combination. In 2009, Merck initiated a phase I trial of MK-8669/MK-0646 in which clinical response was observed in LumB breast cancer patients. A phase II clinical trial has been initiated to test the hypothesis retrospectively.

This talk is also presented as Poster A52.

Citation Information: Clin Cancer Res 2010;16(14 Suppl):PR3.

A gene expression signature of RAS pathway dependence predicts response to PI3K and RAS pathway inhibitors and expands the population of RAS pathway activated tumors

Background

Hyperactivation of the Ras signaling pathway is a driver of many cancers, and RAS pathway activation can predict response to targeted therapies. Therefore, optimal methods for measuring Ras pathway activation are critical. The main focus of our work was to develop a gene expression signature that is predictive of RAS pathway dependence.

Methods

We used the coherent expression of RAS pathway-related genes across multiple datasets to derive a RAS pathway gene expression signature and generate RAS pathway activation scores in pre-clinical cancer models and human tumors. We then related this signature to KRAS mutation status and drug response data in pre-clinical and clinical datasets.

Results

The RAS signature score is predictive of KRAS mutation status in lung tumors and cell lines with high (> 90%) sensitivity but relatively low (50%) specificity due to samples that have apparent RAS pathway activation in the absence of a KRAS mutation. In lung and breast cancer cell line panels, the RAS pathway signature score correlates with pMEK and pERK expression, and predicts resistance to AKT inhibition and sensitivity to MEK inhibition within both KRAS mutant and KRAS wild-type groups. The RAS pathway signature is upregulated in breast cancer cell lines that have acquired resistance to AKT inhibition, and is downregulated by inhibition of MEK. In lung cancer cell lines knockdown of KRAS using siRNA demonstrates that the RAS pathway signature is a better measure of dependence on RAS compared to KRAS mutation status. In human tumors, the RAS pathway signature is elevated in ER negative breast tumors and lung adenocarcinomas, and predicts resistance to cetuximab in metastatic colorectal cancer.

Conclusions

These data demonstrate that the RAS pathway signature is superior to KRAS mutation status for the prediction of dependence on RAS signaling, can predict response to PI3K and RAS pathway inhibitors, and is likely to have the most clinical utility in lung and breast tumors.

Abstract 5560: Biomarker Discovery and Pathway Mapping using Differential Phosphoprofiling of PI3K-Pathway Inhibitors: PRAS40 Correlates with AKT Activation, but not PTEN Expression in Lung and Breast Cancer

Protein phosphorylation plays a key role in cell signaling and pathophysiological alterations in protein kinases and phosphatases contribute to human diseases. We used stable isotope labeling by amino acids (SILAC) in cell culture combined with phospho-antibody based enrichment for quantitative mass-spectrometry-based identification of differentially phosphorylated proteins in response to small-molecule PI3K-pathway inhibition. We quantified over 500 non-redundant serine/threonine phosphopeptides (NSTPs) containing either the AKT-, MAPK-substrate, or PDK1-docking motif. Of these NSTPs, 71 phosphoproteins were modulated by inhibitors targeting either AKT, PDK1 or PI3K/mTOR and a common set of 11 were modulated by all three drugs. Bioinformatics analysis of the regulated phosphoproteins identified core components of the canonical PI3K pathway and showed enrichment in adaptor and scaffolding molecules involved in cell polarity (PAK4), cytoskeletal reorganization (Filamin, Stathmin, Dynamin) vesicle transport (LARP1, VPS13D, SLC20A1), protein translation (S6RP and PRAS40), and transcription (EIF4BP-1). These results have guided the rational selection of antibodies for biomarker and patient stratification assays and a newly developed phosphor-specific antibody against PRAS40T246 shows specificity for oncogenic PI3K-pathway activation in PTEN-deficient mouse prostate tumor tissue by immunohistochemistry. In addition, the phospho-PRAS40T246 biomarker was evaluated across a panel of 67 breast and 96 lung cancer cell lines and in triple negative human breast tumor tissue. In these datasets, phopspho-PRAS40T246 positively correlates with phospho-AKTS473, but not PTEN protein expression. As such, we have positioned PRAS40T246 as a clinically relevant biomarker for the identification of PI3K-pathway activated tumors to enable individualized cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5560.

Abstract 1986: RAS signaling is the key factor determining differential response to PI3K and MAPK targeting compounds in a panel of breast cancer cell lines

We have tested PI3K and MAPK targeting compounds in a panel of 69 breast cancer cell lines. Following the molecular stratification of breast cancer tumors, we have used ER and HER2 biomarkers to stratify cell lines into HER2 positive (HER2+), ER positive (ER+), and triple negative (TN; ER-, PR- and HER2-) subgroups. Both gene expression and response to compounds showed significant differences among the subtypes. Response to mTOR and AKT inhibition was the greatest in ER+ and HER2+ groups (86%, 85% for mTORi and 64%, 77% for AKTi response rates, respectively), whereas TN cell lines showed preferential sensitivity to MEK inhibition (30%). The combination of AKT plus MEK and mTOR plus MEK inhibitors showed synergy in TN tumors (56% and 80% response rates, respectively), particularly in the epithelial subgroup. We believe that RAS pathway deregulation, as reported by a gene expression signature of RAS activation, is the key latent variable that explains the difference in responses. This conclusion is based on pathway activation differences between subtypes. We observe that the TN group has both elevated PI3K and MAPK signaling, evident by high levels of RAS, pERK, and pMEK signatures, whereas the ER+/GGI+ group only has high levels of PI3K signaling. Thus, mTOR, AKT, or MEK alone is insufficient to inhibit the TN lines, whereas the combos are very effective. Finally, we have assessed the prevalence of the EMT and RAS signatures across subtypes of breast tumors. Similar to cell lines, the RAS signature is markedly higher in TN compared to ER+/GGI+ and, to a lesser extent, compared to HER2+ tumors. The EMT signature on the other hand is not significantly different among subtypes. This would suggest that the response patterns observed in ER+/GGI+ and TN/E subtypes of this breast panel will be applicable to a substantial subpopulation of breast tumors (∼38%). Importantly, these breast subtypes represent the largest unmet need and are a high priority for the clinical oncology.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1986.

Abstract 4151: Mutual feedback activation of PI3K and MAPK pathways support combining inhibitors of the two pathways to enhance efficacy

There has been increasing interest in developing cancer therapies targeting PI3K pathway nodes. Unfortunately, the number of tumor types responding to PI3K pathway inhibitors as monotherapy has been limited, since most cancer cells accumulate genetic alterations that result in the constitutive activation of a complex network of proliferation and survival signals. As such, the inhibition of a single survival/proliferation pathway or node within this broader network may be circumvented by constitutive activation (or feedback activation) of an alternative survival pathway, and thus be insufficient for inducing a clinical response. Therefore, in most tumor types, dual pathway inhibition, guided by an in-depth understanding of feedback and cross-talk between pathways, may be required to induce tumor regression. Here we present a nonclinical study exploring mutual feedback activation of MAPK and PI3K pathways. Inhibition of the PI3K pathway by MK-2206 (AKT inhibitor) or MK-8669 (mTOR inhibitor) resulted in feedback activation of MAPK pathway nodes in subsets of lung cell lines. Similarly, inhibition of the MAPK pathway by a MEK inhibitor resulted in feedback activation of the PI3K pathway. Notably, a lack of such feedback activation was associated with sensitivity to the mono inhibitors. The strength of the feedback activation correlated with changes of several receptor tyrosine kinases, suggesting them as a part of the feedback mechanism. Finally, combined inhibition of both MAPK and PI3K pathways synergistically inhibited the feedback activation of both pathways and led to improved in vitro efficacy. Taken together, our findings identify mutual feedback activation of the PI3K and MAPK pathways in response to specific inhibitors and underscore the importance of combined therapeutic approaches with inhibitors to both pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4151.

Abstract 107: Genome-wide analysis reveals that cMET is a driver of RAS signaling and implicates RAS activation status as a predictor for response to cMET inhibitors

In order to facilitate the development of HGF/ c-MET inhibitors, we undertook a genome-wide analysis to identify a “c-MET activation signature” that could be used to identify tumors that are potentially dependent on HGF / c-MET signaling and therefore more responsive to HGF/ c-MET inhibition.

We first developed a c-MET co-expression signature by identifying genes that correlate with the mRNA expression of c-MET across internal panels of kidney, lung, and colorectal tumors. Many genes correlated with the expression of c-MET, including the epidermal growth factor receptor (EGFR). In order to assess the biology of genes co-expressed with cMET, we performed pathway enrichment analysis to identify pathways or pre-existing signatures that were enriched in this cMET co-expression signature more than we would expect by chance. Our previously reported RAS signature (Loboda et al, 2009 AACR annual meeting) was the top pathway enrichment, indicating a link between genes involved in RAS signaling and cMET expression across tumors. To further assess this relationship, we tested the correlation between c-MET and our RAS signature across independent cohorts of breast and lung tumors, including primary and metastatic samples. A strong correlation between c-MET expression and our RAS signature was present in all cases and was conserved in metastatic tumors.

We then assessed the relationship between c-MET and RAS activation using reverse-phase protein arrays measuring approximately 70 proteins across a panel of 89 lung cancer cell lines. Four proteins were identified that significantly correlated positively with the RAS signature: total ERBB4, pMEK, pERK, and pMET. The finding that pMET correlated with RAS signature in addition to pMEK and pERK supports the connection between c-MET signaling and RAS activation, as this relationship is observed on the phospho-protein as well as mRNA levels.

Taken together, these data suggest that cMET can serve as a driver of RAS signaling. To test this, we performed a xenograft study in which GTL-16 xenografts (MET amplified gastric cancer cell line) were treated with a novel small molecule inhibitor of c-MET (MK-8033). Animals were treated with vehicle or with a single dose of 10, 33, 66, 100, or 200 mpk MK-8033. At each dose, we collected samples for profiling at 2, 8, and 12 hours post-dose. MK-8033 treatment caused a dose-and time-dependent inhibition of the RAS signature at all three time points, and the level of RAS signature inhibition was related to efficacy. These data support the hypothesis that cMET is a driver of RAS signaling in some tumor contexts and suggest that basal levels of RAS pathway activation may be an important determinant of response to HGF / c-MET inhibition in the clinic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 107.

Bioinformatic analysis of autism positional candidate genes using biological databases and computational gene network prediction

Common genetic disorders are believed to arise from the combined effects of multiple inherited genetic variants acting in concert with environmental factors, such that any given DNA sequence variant may have only a marginal effect on disease outcome. As a consequence, the correlation between disease status and any given DNA marker allele in a genomewide linkage study tends to be relatively weak and the implicated regions typically encompass hundreds of positional candidate genes. Therefore, new strategies are needed to parse relatively large sets of 'positional' candidate genes in search of actual disease-related gene variants. Here we use biological databases to identify 383 positional candidate genes predicted by genomewide genetic linkage analysis of a large set of families, each with two or more members diagnosed with autism, or autism spectrum disorder (ASD). Next, we seek to identify a subset of biologically meaningful, high priority candidates. The strategy is to select autism candidate genes based on prior genetic evidence from the allelic association literature to query the known transcripts within the 1-LOD (logarithm of the odds) support interval for each region. We use recently developed bioinformatic programs that automatically search the biological literature to predict pathways of interacting genes (PATHWAYASSIST and GENEWAYS). To identify gene regulatory networks, we search for coexpression between candidate genes and positional candidates. The studies are intended both to inform studies of autism, and to illustrate and explore the increasing potential of bioinformatic approaches as a compliment to linkage analysis.

Developing a managed care delivery system in New York State for Medicaid recipients with HIV

In the state of New York, models of care known as HIV Special Needs Plans (HIV SNPs) are being developed to meet the unique health and medical needs of Medicaid recipients with HIV. Establishing managed care plans for the 80,000 to 100,000 HIV-infected Medicaid recipients residing in the state has required considerable effort, including distributing planning grants to solicit information and recommendations regarding program and fiscal policy; convening a workgroup to facilitate discussions between the state and the provider and consumer communities; conducting a longitudinal survey to assess the impact of managed care on persons with HIV; and developing a longitudinal, person-based, encounter-level database representing the clinical and service utilization histories of more than 100,000 patients for state fiscal years 1990 to 1996. The key fiscal issues identified and discussed were capitation rates, initial capitalization levels, and risk-adjustment mechanisms. Other pertinent issues included the importance of a benefits package supporting a comprehensive, integrated continuum of state-of-the-art services; marketing and enrollment; attention to provider and consumer training and education needs; and interdependence of financial reimbursement and benefits packages. From our experience in New York State, we conclude that a successful model of Medicaid managed care for persons with HIV should build on the existing infrastructure of services, using a collaborative process among government agencies, healthcare providers, and HIV/AIDS consumer communities. A future challenge lies in the implementation of the HIV SNP model and evaluation of its soundness and ability to ensure quality healthcare services.

Congenital hypothyroidism screening in the West Bank: a test case for screening in developing regions

Screening for congenital hypothyroidism (CH) among the Arab population of the West Bank began in May 1987 as part of the neonatal screening program in Israel. In the West Bank many infants are born at home or are released from the hospital on the 1st day after birth and thus cannot be screened. However, we tried to reach the infants before the age of 1 month at the maternal and child health centers, where they receive immunization. In this screening program, 64% of the infants were sampled by the 1st week and 93% by 3 weeks of life. In contrast to the screening in Israel, where thyroxine determination is followed by thyroid-stimulating hormone measurement, in the West Bank thyroid-stimulating hormone was tested first in order to decrease the recall rates. From June 1990 to February 1994, 49,694 infants were screened in the West Bank, of whom 24 with CH were detected (an incidence of 1:2,070). From January 1987 to February 1994, 28,938 infants were screened in East Jerusalem, of whom 20 with CH were detected (incidence 1:1,447). There were differences between the incidence rates in the various districts. The incidence rates were higher than those reported from industrialized countries, but similar to those found in Saudi Arabia. This may be due to the high degree of consanguineous marriages among Arab populations and to environmental factors. In conclusion, in spite of the many difficulties, both practical and political, CH screening in the West Bank is feasible. Although screening all newborns shortly after birth is not possible, this study shows that a high percentage of them can be screened at a time when they can still be effectively treated. Our results could be used in due time as a baseline for a future independent screening program.

[Nursing home-acquired pneumonia--guidelines for hospitalization]

To determine if there are any specific features of nursing-home acquired pneumonia we carried out a retrospective study in a nursing home between 1995-1996, based on clinical and laboratory data. We found no correlation between these findings and the severity of pneumonia, so it would be hazardous to determine rigid guidelines. These patients should be treated in the nursing home as long as conditions allow, in order to avoid hospitalization.

Malignant melanoma of the head and neck. Clinical and immunological considerations

Prolonged exposure to sun for long periods during most of the year has led to an increase in the frequency of malignant melanoma in Israel, especially for head and neck (H&N) melanoma. H & N melanoma is found in males more than in females and diagnosed when already locally advanced. The disease-free interval between treatment of the primary lesion and recurrence of the disease correlated with the patient's age and the depth of invasion according to Breslow. A higher recurrence rate correlated with male gender, location in the scalp, and the stage of the disease. Metastatic disease involved the lungs, liver, and brain and responded poorly to systemic therapy. Improved survival was related to female gender, early stage of the disease, low Breslow thickness, and location of the primary lesion elsewhere than the scalp. Immunologically, we found that the titers of antimelanoma antibodies in patients with metastatic disease originating in the area of the head and neck were higher than the titer in disease-free H & N melanoma patients (p = 0.05). Moreover, patients with metastatic H & N melanoma had a higher titer of antityrosinase antibodies compared with healthy subjects. These two types of antibodies might be used as markers for disease progression in H & N melanoma. The more aggressive character of H & N melanoma was not reflected by different titers of antimelanoma antibodies nor by antityrosinase antibodies in patients with H & N versus non-H & N melanoma.

Effects of divalent metal ions on the fluorescence and glucose-quenching of yeast hexokinase isozymes

Titrations of the quenching of the tryptophan fluorescence of yeast hexokinase isozymes P-I and P-II by Mg2+, Mn2+, Ca2+, Cd2+, and Zn2+ ions and by glucose in the presence of each of these ions (10mM) were performed at pH 5.5 and 6.5 at 20 degrees C. At the higher pH there was a reversal of the type of glucose-binding cooperativity for P-II from negative to positive when either Mn2+ or Ca2+ was present in the buffered isozyme solution before the glucose titration, whereas Mg2+ caused the glucose binding to become noncooperative. Zn2+ and Cd2+ decreased the glucose quenching of P-II fluorescence drastically at pH 5.5, from a value of 15% in buffer to only 4%. Thus, only these two ions, of the five studied, cause the conformation change that results in quenching of the glucose-quenchable cleft tryptophan of P-II. Glucose binding to the P-I isozyme exhibited positive cooperativity in the presence of either Ca2+, Mg2+, or Mn2+, as well as in buffer alone, at both pH's. At the lower pH, Ca2+ enhanced the efficiency of glucose quenching of P-I fluorescence several-fold, while Mn2+ increased it only about 40% and Mg2+ not at all. Further, Ca2+ raised the degree of cooperativity (Hill coefficient) of glucose binding to P-I at this pH from the value of 1.42 in buffer and in the presence of Mg2+ and Mn2+ to 1.94, i.e., almost up to the highest possible value, 2, for dimeric hexokinase. However, at pH 6.5 the Ca2+ effect on the cooperativity was negligible, while Mg2+ and Mn2+ decreased the coefficient from 1.6 in buffer to about 1.4. The biological implications of these diverse metal ion effects are discussed.

Effects of glucose and magnesium ion on the quenching of yeast hexokinase fluorescence by acrylamide

To probe the effects of the substrate, glucose, and the cofactor, Mg2+, on the structure of hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1), titrations of the tryptophan fluorescence of yeast hexokinase isozyme P-II(B) were performed. Acrylamide was used as a quenching titrant in the absence and in the presence of glucose and Mg2+ singly and together at pH 5.5 and 8.3 at 20 degrees C. The four tryptophan residues of the monomeric subunit of yeast hexokinase may be classified as two surface residues, one being highly accessible to dissolved I- and one with restricted accessibility to I-, one glucose-quenchable residue in the cleft, and one buried (Kramp, D.C. and Feldman, I. (1978) Biochim. Biophys. Acta 537, 406--416). The acrylamide data were analyzed by least-squares computer analysis for quenching constants and fractional fluorescence values of the tryptophan residues. The quenching constants measure the accessibilities of the residues to the quencher, while the fractional fluorescences are related to the microenvironments of the fluorophores. At each pH value, glucose altered the quenching constants, but not the fractional fluorescence, of the tryptophan residues. Mg2+ greatly accentuated at this glucose effect, especially for the surface residue near the cleft opening. Comparison of acrylamide- and I-quenching data shows that this particular residue has a positively charged microenvironment. A pH change from 5.5 to 8.3 increased the acylamide-accessibility of the cleft tryptophan but did not seem to influence accessibility of the surface residues or the buried residue significantly, thus strengthening our previous conclusion that the cleft opening is small enough at pH 5.5 to partially restrict entrance of organic molecules and negative ions. However, with saturating glucose present there was a pH effect on the surface residue accessibility. Titrations in 55 vol.% glycerol suggest the presence of transient channels (not just holes) in the hexokinase structure, which allows penetration of the protein by solution. Consequently, the buried tryptophan residue is quenched more strongly by dissolved acrylamide than is attributable to diffusion of quencher through the protein matrix.

Effects of free magnesium and alkali ions on the conformation and glucose-binding strength of yeast hexokinase isozymes

Titrations of the tryptophan fluorescence of yeast hexokinase (ATP:D-hexose 6-phosphortransferase, EC 2.7.1.1.) isozymes P-I (A) and P-II (B) were performed with Mg2+, Li+, Na+ and K+ as titrant in absence and in presence of glucose, and vice versa, at pH 8.3 and 5.5 at 20 degrees C. Mg2+ quenches the fluorescence of surface tryptophan primarily and does so by producing a conformational change which alters the microenvironment of the tryptophan. For both isozymes Mg2+ exerts a specific ion effect, i.e. significantly larger than the ionic strength (I) effect, which enhances the glucose quenching by causing a conformation change which increases the glucose-binding constant. For the P-I isozyme glucose binding exhibits positive cooperativity at both pH 8.3 and 5.5 when the ionic strength (I) is low, i.e. significantly larger than the ionic strength (I) effect, which enhances the glucose quenching by causing a conformation change which increases the glucose-binding constant. For the P-I isozyme glucose binding exhibits positive sooperativity at both pH 8.3 and 5.5 when the ionic strength (I) is low, i.e. 0.04 or less, regardless of which of the above four cations is present. For P-II, however, glucose binding is non-cooperative at pH 8.3 regardless of I or the cation species and at pH 5.5 and low I with K+ or Mg2+ as the predominant cation present, but there is apparent negative cooperativity at pH 5.5 and low I when Na+ or Li+ predominates. These results are discussed in terms of known structural characteristics of the isozymes.