Elongated neutrophil-derived structures are blood-borne microparticles formed by rolling neutrophils during sepsis

Rolling neutrophils form tethers with submicron diameters. Here, we report that these tethers detach, forming elongated neutrophil-derived structures (ENDS) in the vessel lumen. We studied ENDS formation in mice and humans in vitro and in vivo. ENDS do not contain mitochondria, endoplasmic reticulum, or DNA, but are enriched for S100A8, S100A9, and 57 other proteins. Within hours of formation, ENDS round up, and some of them begin to present phosphatidylserine on their surface (detected by annexin-5 binding) and release S100A8-S100A9 complex, a damage-associated molecular pattern protein that is a known biomarker of neutrophilic inflammation. ENDS appear in blood plasma of mice upon induction of septic shock. Compared with healthy donors, ENDS are 10-100-fold elevated in blood plasma of septic patients. Unlike neutrophil-derived extracellular vesicles, most ENDS are negative for the tetraspanins CD9, CD63, and CD81. We conclude that ENDS are a new class of bloodborne submicron particles with a formation mechanism linked to neutrophil rolling on the vessel wall.

Extracellular Vesicle and Particle Biomarkers Define Multiple Human Cancers

There is an unmet clinical need for improved tissue and liquid biopsy tools for cancer detection. We investigated the proteomic profile of extracellular vesicles and particles (EVPs) in 426 human samples from tissue explants (TEs), plasma, and other bodily fluids. Among traditional exosome markers, CD9, HSPA8, ALIX, and HSP90AB1 represent pan-EVP markers, while ACTB, MSN, and RAP1B are novel pan-EVP markers. To confirm that EVPs are ideal diagnostic tools, we analyzed proteomes of TE- (n = 151) and plasma-derived (n = 120) EVPs. Comparison of TE EVPs identified proteins (e.g., VCAN, TNC, and THBS2) that distinguish tumors from normal tissues with 90% sensitivity/94% specificity. Machine-learning classification of plasma-derived EVP cargo, including immunoglobulins, revealed 95% sensitivity/90% specificity in detecting cancer. Finally, we defined a panel of tumor-type-specific EVP proteins in TEs and plasma, which can classify tumors of unknown primary origin. Thus, EVP proteins can serve as reliable biomarkers for cancer detection and determining cancer type.

Abstract A37: Immuno-oncological efficacy of RXDX-106, a novel TAM (TYRO3, AXL, MER) family small-molecule kinase inhibitor

Background: The TAM family of receptor tyrosine kinases (RTKs), TYRO3, AXL, and MER, have emerged as attractive targets for cancer therapy. In cancer cells, overexpression of TAM RTKs is associated with resistance and a mesenchymal phenotype. In immune cells, TAM RTKs play a key homeostatic role as negative regulators of immune responses, contributing to the evasion of cancer cells from immune surveillance. RXDX-106 is a potent and selective TAM family inhibitor in preclinical development. Previously, in several syngeneic tumor models, we have demonstrated that RXDX-106 alone inhibited tumor growth, whereas such benefit was reduced when the tumors grew in immunocompromised athymic nude mice. In addition, RXDX-106 induced favorable polarization of the tumor infiltrating immune cells towards an anti-cancer phenotype. Here we sought (1) to evaluate the efficacy of RXDX-106 as a single agent and in combination with immune checkpoint inhibitors; (2) to identify the immuno-modulatory mechanisms of action; (3) to explore the reciprocal regulation of TAM expression on cancer and immune cells in the tumor microenvironment; and (4) to decipher how pharmacological inhibition of TAM signaling pathways on both tumor and immune cells would be beneficial, given their complex regulation and intimate relationship in the tumor microenvironment.

Methods and Results: In the present study, we demonstrated that tumor growth inhibition in an MC38 model was associated with a significant increase in tumor associated M1 macrophages, an increase in CD169hi antigen presenting macrophages, and upregulation of PD-L1. In addition, we observed a higher ratio of CD8+/CD4+ T cells and increased expression of CD69 and PD-1 on CD8+ T cells, all indicative of activation of cytotoxic T cells. Finally, we observed an increase in Granzyme B and IFNγ with a concomitant decrease in VEGF in tumor cell lysates, evidence supporting T cell activation and M1 polarization of macrophages. Furthermore, in a CT26 syngeneic model, we demonstrated that RXDX-106 inhibited tumor growth as a single agent, and the effect was further potentiated by combination therapy with immune checkpoint inhibitors, as evidenced by upregulation of anti-tumor gene expression patterns, upregulation of anti-tumor cytokines in the tumor cell lysates, and an increase in T cell function. Finally, in an AXL-driven tumor model, we demonstrated that AXL expressing tumors induced a pro-tumorigenic immune environment, and treatment with RXDX-106 resulted in complete tumor regression and re-polarization of macrophages towards an M1, anti-tumor phenotype.

Conclusion: RXDX-106 has the potential to restore and enhance immune function in macrophages and T cells, resulting in repolarization of the immune response towards an anti-tumor microenvironment. The unique mechanism of activating both innate and adaptive immunity, plus regulating cross-talk between immune cells and tumor cells by RXDX-106 supports clinical development of RXDX-106 to potentially treat a wide variety of cancers.

Citation Format: Yumi Yokoyama, Erin D. Lew, Colin Walsh, Jack Lee, Joanne Oh, Elizabeth A. Tindall, Robin Nevarez, Amy Diliberto, Heather Ely, Ruth Seelige, Amanda Albert, Jack Bui, Gary Li. Immuno-oncological efficacy of RXDX-106, a novel TAM (TYRO3, AXL, MER) family small-molecule kinase inhibitor [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2017 Oct 1-4; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2018;6(9 Suppl):Abstract nr A37.

Automated Analysis of Clinical Flow Cytometry Data: A Chronic Lymphocytic Leukemia Illustration

Flow cytometry is used in cell-based diagnostic evaluation for blood-borne malignancies including leukemia and lymphoma. The current practice for cytometry data analysis relies on manual gating to identify cell subsets in complex mixtures, which is subjective, labor-intensive, and poorly reproducible. This article reviews recent efforts to develop, validate, and disseminate automated computational methods and pipelines for cytometry data analysis that could help overcome the limitations of manual analysis and provide for efficient and data-driven diagnostic applications. It demonstrates the performance of an optimized computational pipeline in a pilot study of chronic lymphocytic leukemia data from the authors' clinical diagnostic laboratory.

Abstract 4698: Immuno-oncological efficacy of RXDX-106, a novel, selective and potent small molecule TAM (TYRO3, AXL, MER) inhibitor

The TAM family of receptor tyrosine kinases (RTKs), TYRO3, AXL, and MER, has been implicated in the pathogenesis and progression of many cancer types. In cancer cells, overexpression of TAM RTKs is associated with resistance and mesenchymal phenotype. In immune cells, TAM RTKs play a key homeostatic role as negative regulators of immune responses, contributing to the evasion of cancer cells from immune surveillance. Here we studied expression as well as functional modulation of TAM RTKs on immune cells in the tumor microenvironment and evaluated whether RXDX-106, a selective and potent, pseudo-irreversible small molecule inhibitor of TAM RTKs could restore and enhance host immunity against cancer. We first evaluated the expression of TAM RTKs on immune cells in non-tumor bearing mice and tumor bearing mice. Tumor bearing animals showed increased expression of TAM RTKs in subsets of immune cells such as lymph node macrophages and T cells, compared to non-tumor bearing mice. Particularly, TAM expression was upregulated in CD8+ T cells in tumors, suggesting that the increased expression could restrain T cell activation and mediate exhaustion. RXDX-106 reduced TAM phosphorylation on macrophages at concentrations as low as 2.5 nM, and inhibited AXL- and MER-dependent in vitro phagocytosis with an IC50 of 10.8 and 9.1 nM, respectively. In syngeneic mouse models, including 4T-1 breast cancer model and CT26 colon cancer model, RXDX-106 dose-dependently inhibited tumor growth and demonstrated further tumor growth inhibition in combination with anti-CTLA-4 or anti-PD-1 antibodies. The tumor growth inhibition was associated with increased total T cells, decreased T-regulatory cells, and increased IFN-γ production by NK cells in the tumor. RXDX-106 also increased IFN-γ levels in the blood when combined with anti-PD-1 antibody. Although RXDX-106 had no effect on T cell proliferation in vitro, it could increase the proliferation of T cells in lymph nodes in vivo. In conclusion, we demonstrated that tumors could induce TAM expression on subsets of T cells and that inhibition of TAM RTK activity by the small molecule inhibitor, RXDX-106, could potentially remove the molecular “brake” on immune activation in macrophages, NK cells and T cells, resulting in repolarization of the immune response towards an anti-tumor environment. The unique mechanism of activating both innate and acquired immunity by RXDX-106, and the compelling preclinical data in cell line and syngeneic models, support the clinical development of RXDX-106 in a wide variety of cancers.

Citation Format: Yumi Yokoyama, Erin D. Lew, Ruth Seelige, Colin Walsh, Maria Barrera, Elizabeth Tindall, Joanne Oh, Heather Ely, Amy Diliberto, Amanda Albert, Jack Bui, Gary Li. Immuno-oncological efficacy of RXDX-106, a novel, selective and potent small molecule TAM (TYRO3, AXL, MER) inhibitor [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 4698. doi:10.1158/1538-7445.AM2017-4698

eIF5A-PEAK1 Signaling Regulates YAP1/TAZ Protein Expression and Pancreatic Cancer Cell Growth

In pancreatic ductal adenocarcinoma (PDAC), mutant KRAS stimulates the translation initiation factor eIF5A and upregulates the focal adhesion kinase PEAK1, which transmits integrin and growth factor signals mediated by the tumor microenvironment. Although eIF5A-PEAK1 signaling contributes to multiple aggressive cancer cell phenotypes, the downstream signaling processes that mediate these responses are uncharacterized. Through proteomics and informatic analyses of PEAK1-depleted PDAC cells, we defined protein translation, cytoskeleton organization, and cell-cycle regulatory pathways as major pathways controlled by PEAK1. Biochemical and functional studies revealed that the transcription factors YAP1 and TAZ are key targets of eIF5A-PEAK1 signaling. YAP1/TAZ coimmunoprecipitated with PEAK1. Interfering with eIF5A-PEAK1 signaling in PDAC cells inhibited YAP/TAZ protein expression, decreasing expression of stem cell-associated transcription factors (STF) including Oct4, Nanog, c-Myc, and TEAD, thereby decreasing three-dimensional (3D) tumor sphere growth. Conversely, amplified eIF5A-PEAK1 signaling increased YAP1/TAZ expression, increasing expression of STF and enhancing 3D tumor sphere growth. Informatic interrogation of mRNA sequence databases revealed upregulation of the eIF5A-PEAK1-YAP1-TEAD signaling module in PDAC patients. Taken together, our findings indicate that eIF5A-PEAK1-YAP signaling contributes to PDAC development by regulating an STF program associated with increased tumorigenicity. Cancer Res; 77(8); 1997-2007. ©2017 AACR.

Morphometric analysis of immunoselection against hyperploid cancer cells

An at least transient increase of ploidy, usually by whole genome duplication, is a frequent event in oncogenesis, explaining the cytogenetic features of at least 40% of solid cancers. Here, we show that fibrosarcomas induced by the carcinogen methylcholanthrene (MCA) are distinct with respect to their ploidy status when they arise in immunocompetent wild type versus severely immunodeficient Rag2^−/−γc^−/− mice. MCA-induced fibrosarcomas are particularly hyperploid if they develop in an immunodeficient setting, correlating with higher DNA content, increased nuclear surface, as well as hyperphosphorylation of eukaryotic initiation factor 2` (eIF2`), a biomarker indicating endoplasmic reticulum (ER) stress. Upon transfer of such cells into wild type mice, such hyperploid, ER-stressed cells (that originated in Rag2^−/−γc^−/− mice) fail to proliferate and actually induce a protective anticancer immune response. In contrast, such cells do form tumors in Rag2^−/−γc^−/− recipients (which lack T, B and NK cells) as well as in Rag2^−/− recipients (which only lack T and B lymphocytes) and conserve their hyperploidy as well as eIF2` hyperphosphorylation. To measure these parameters, we developed a morphometric analysis tool that is applicable to immunohistochemistry of formaldehyde-fixed, paraffin-embedded tissues. This software automatically identifies and quantifies the surface of nuclei and determines the intensity of eIF2` phosphorylation within a perinuclear region of interest. Comparative analyses performed on cultured cells and tissue sections validated the accuracy of this method, which can be used to investigate ploidy and ER stress in cancers in situ.

Abstract 4888: The novel cytokine IL-17D at the intersection of cellular stress and tumor immunity

Our laboratory has recently identified a novel role for the cytokine IL-17D as an important mediator of the antitumor immune response; and, the loss of IL-17D as a key component of tumor progression. Our data show for the first time that overexpression of the cytokine IL-17D is sufficient to induce tumor rejection or growth delay. Tumors expressing IL-17D displayed an increased infiltration of natural killer (NK) cells, which gave way to a commensurate increase of M1-type macrophages. While examining the regulation of IL-17D, we came across the surprising finding that IL-17D can be induced by oxidative stress signals via the transcription factor nrf2. Nrf2, responsible for regulating the expression of the anti-oxidant response element genes, is known as the primary cellular responder to oxidative stress. Although the role of nrf2 in cancer biology has been well studied, the role of nrf2 in the regulation of immune responses (particularly via IL-17D) has yet to be defined. We find that nrf2 is necessary to induce IL-17D expression in a variety of tumor and non-tumor cells, and that this regulation is active in tumor progression. These studies constitute an intriguing and novel connection between oxidative cellular stress and immune activation.

Citation Format: Robert Saddawi-Konefka, Jack Bui. The novel cytokine IL-17D at the intersection of cellular stress and tumor immunity. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4888. doi:10.1158/1538-7445.AM2014-4888

Abstract 3659: Engagement of myelomonocytic siglecs by tumor-associated ligands modulates innate immune responses to cancer

Sialic acids are dominant glycans on vertebrate cell surfaces, mediating roles as diverse as influenza infection, leukocyte trafficking and neural plasticity. It has long been known that malignant cells upregulate sialic acids, but few reasons for this have so far been elucidated. In apparently unrelated work, we have recently found that certain pathogenic bacteria coat themselves with sialic acids, thereby dampening innate immune responses, via engagement of inhibitory Siglecs (sialic acid binding Ig-like lectins). We therefore hypothesized that hypersialylated carcinoma cells might similarly engage Siglecs and modulate immune cell function. Confirming this hypothesis, we now have the first demonstration of the involvement of Siglecs in cancer progression in vivo.

Siglec-9 is the most abundant inhibitory Siglec on human neutrophils and monocytes/macrophages. We first demonstrate that ligands for Siglec-9 are strongly upregulated in human carcinomas. We further provide evidence that ligands on carcinoma cells can inhibit neutrophil activation and killing of tumor cells by neutrophils. We then show that mice lacking Siglec-E (the murine functional equivalent of Siglec-9) have an increased immunosurveillance in autochthonous and transplantation models, which could be reversed by transgenic expression of Siglec-9 in myelomonocytic cells. Studies of later phases of tumor progression however showed that Siglec-E/-9 inhibits polarization of M2 macrophages and therefore impairs angiogenesis and tumor growth. In keeping with this dualistic role of myelomonocytic Siglecs during different phases of cancer progression, survival of non-small cell lung cancer patients with a polymorphism that reduced ligand binding to Siglec-9 had initially an improved survival, suggesting an increased immunosurveillance, but this effect was lost during longer followup.

Our results identify inhibitory CD33-related myelomonocytic Siglecs as important players in cancer biology and as potential targets for immunomodulatory therapy. We show that hypersialylated carcinoma cells modulate the innate immune response by engaging Siglec-9 and inhibit either immunosurveillance or cancer-related inflammation. Our data also exemplify the dualistic role of innate immune cells and their receptors in cancer progression depending on the context and the microenvironment, i.e., growth control by immunosurveillance or growth support by cancer-related inflammation.

Citation Format: Heinz Läubli, Oliver M. T. Pearce, Flavio Schwarz, Lingquan Deng, Michal Stanczak, Liwen Deng, Andrea Verhagen, Patrick Secrest, Chrissy Lusk, Ann G. Schwartz, Nissi Varki, Jack Bui, Ajit Varki. Engagement of myelomonocytic siglecs by tumor-associated ligands modulates innate immune responses to cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3659. doi:10.1158/1538-7445.AM2014-3659

Hormesis in cancer immunology: Does the quantity of an immune reactant matter?

We recently reported that tumor-directed antibodies could either stimulate, or inhibit, tumor progression, dependent upon the dosage used. The narrow range over which this immune response curve (IRC) occurs is surprising. Here we discuss features of the IRC, the mechanisms identified so far, and the potential clinical implications.

Lenalidomide increases peripheral T regulatory phenotype cells in patients with HIV associated Kaposi Sarcoma (P2030)

Kaposi Sarcoma, an angioproliferative vascular tumor, is the most common malignancy in patients with HIV and presents a treatment conundrum because of its variable natural history. Lenalidomide is a drug that has immune-modulatory, anti-neoplastic, and anti-angiogenic properties. It is used in the treatment of myelodysplastic disease and multiple myeloma, but its in vivo effects on peripheral blood immune activity is not fully explored. In this preliminary report from a phase I/II trial of lenalidomide in the treatment of HIV associated Kaposi Sarcoma, we found that lenalidomide increased the number and percentage of T regulatory phenotype cells in the peripheral blood. In patients with measurable regression of Kaposi Sarcoma lesion size as well as number of lesions, there was also an observable accumulation in FOXP3 expressing cells in the Kaposi Sarcoma lesion. These findings enable us to speculate on three novel concepts: 1) lenalidomide increases the frequency of circulating T regulatory phenotype cells, 2) lenalidomide’s anti-angiogenic mechanism may be due to T regulatory cell induction, and 3) in contrast to their role in promoting tumor growth by inhibiting tumor immunosurveillance, T regulatory cells may inhibit angioproliferative tumors therefore act as an effective therapeutic agent for tumors such as Kaposi Sarcoma.

The novel cytokine IL-17D at the intersection of cellular stress and immune activation (P1364)

Our laboratory has recently identified a novel role for the cytokine IL-17D as an important mediator of the antitumor immune response, and the loss of IL-17D as a key component of tumor progression. Our data show for the first time that overexpression of the cytokine IL-17D is sufficient to induce tumor rejection or growth delay. Tumors expressing IL-17D displayed an increased infiltration of natural killer cells, which gave way to a commensurate increase of M1-type macrophages. While examining the regulation of IL-17D, we came across the surprising finding that IL-17D can be induced by oxidative stress signals via the transcription factor nrf2. Nrf2, responsible for regulating the expression of the anti-oxidant response element genes, is known as the primary cellular responder to oxidative stress. Although the role of nrf2 in cancer biology has been well studied, the role of nrf2 in the regulation of immune responses (especially via IL-17D) has yet to be defined. We find that nrf2 is necessary to induce IL-17D expression in a variety of tumor and non-tumor cells, and that this regulation is active in both tumor progression and viral infection. These studies constitute an intriguing and novel connection between oxidative cellular stress and immune activation.

IL-17D, natural killer cells, and macrophages collaborate to promote tumor rejection (P2097)

The process of cancer immunoediting generates a repertoire of cancer cells that can persist in immune competent hosts. In its most complex form, this process begins with the elimination of highly immunogenic unedited tumor cells followed by the eventual escape of less immunogenic, edited cells. However, it is not known whether editing can also change the global gene expression profile of developing tumor cells. Here we show using a gene microarray study that the novel cytokine interleukin 17D (IL-17D) is highly expressed in certain unedited but not edited mouse tumor cell lines or certain human tumors. Moreover, forced expression of IL-17D in edited tumor cells induced rejection by stimulating monocyte chemotactic protein 1 (MCP-1, aka CCL2) production from tumor endothelial cells leading to the recruitment of natural killer (NK) cells. We go on to show that NK cells can promote the accumulation of M1-type macrophages. Altogether, these results identify IL-17D as a novel cytokine and describe one mechanism by which IL-17D can induce tumor rejection.

Immunosurveillance of cancer stem cells (P2217)

The cancer stem cell (CSC) hypothesis stipulates that tumors follow a hierarchical organization where a subpopulation of cells endowed with stem cell characteristics initiates and maintains the malignant progression. Using the murine MCA sarcoma model system, a widely recognized model for studying cancer immunosurveillance and rejection mechanisms, we sought to explore how hierarchical tumor progression occurs during cancer immunosurveillance. The first step was to define CSC in the MCA sarcoma model. We identified an interesting heterogeneity of the tumor population based on Sca1 and CD90 expression. Purification of the Sca1+ and Sca1+/CD90+ in various cell lines and subsequent in vitro culture demonstrated that the Sca1+/CD90-population is able to regenerate the initial tumor heterogeneity. Transplantation of those two populations in RAGxγc-/- hosts demonstrated either a more rapid onset of sarcoma in mice injected with Sca1+ cells. Interestingly, phenotypic analysis of escaping tumors revealed an increase in Sca1+ cells. Finally, in vitro treatment with IFNg led to a substantial increase in Sca1 expression that correlated with an increase in cells' stemness properties as suggested by the elevated sphere forming capacity of IFNg treated cells. This data suggest that cancer stemness may be modulated by anti-cancer immune responses and may represent an additional mechanism of tumor immune escape.

IL-17D mediated cancer rejection (162.26)

Immune system interaction with cancers can either enhance or prevent tumor formation. Cytokine secretion by immune infiltrates and tumor cells are important in regulating this process. IL-17A, a pro-inflammatory member of the IL-17 family, has been shown to have conflicting results in regards to cancer progression or regression. Other members of the IL-17 family, such as IL-17D, have no known roles in immune responses to cancer, or endogenous function. Our lab possesses matched methylcholanthrene (MCA)-induced tumor cell lines that will continuously grow (Progressors) or reject (Regressors) after transplantation into syngeneic WT mice. The regresssor cell lines can grow in immune-deficient RAG2-/- mice, indicating that their rejection in WT mice requires an intact immune system. Our lab has used these cell lines to identify differential cytokine expression profiles from microarray analysis. We have obtained data that shows IL-17D transcript and protein are significantly overexpressed in regressor cell lines when compared to progressor cell lines. Overexpression of IL-7D in progressor tumor cell lines leads to their rejection in WT mice in a NK cell dependent manner. We hypothesize that IL-17D expression in regressor cell lines leads to immune-mediated tumor rejection by recruiting NK cells that polarize M1 macrophages in the tumor microenvironment.

Cancer immunoediting by the innate immune system in the absence of adaptive immunity (162.3)

Cancer immunoediting is the process whereby immune cells protect against cancer formation and sculpt the immunogenicity of developing tumors. The complete process of immunoediting requires both innate and adaptive immunity, but it remains unclear to what extent innate immunity alone is capable of immunoediting. To determine whether the innate immune system can edit tumor cells in the absence of adaptive immunity, we compared the incidence and immunogenicity of 3’methylcholanthrene-induced sarcomas in syngeneic wild-type, RAG2-/-, and RAG2-/-x γc-/- mice. We found that innate immune cells could indeed manifest cancer immunoediting activity in the absence of adaptive immunity. This activity required γc and IFNγ, which mediated the induction of M1 macrophages. M1 macrophages could be elicited by administration of CD40 agonists, thereby restoring editing activity in RAG2-/-x γc-/- mice. Our results suggest that in the absence of adaptive immunity, natural killer cell production of IFNγ induces M1 macrophages, which act as important effectors during cancer immunoediting.

The unique pathophysiology of early-onset severe preeclampsia: role of decidual T regulatory cells

Immunological mechanisms play a pivotal role in the pathophysiology of preeclampsia. T regulatory cells (Treg cells, FoxP3(+)) suppress the cytotoxic T cell (CD8(+)) and natural killer (NK) cell response, thereby promoting immunological tolerance to the fetus. In peripheral blood, Treg cells are elevated during pregnancy, decrease throughout gestation, and are decreased in preeclampsia. To determine their role at the implantation site, we characterized the proportion of decidual Treg and CD8+ cells, and compared these with placental histology, villous sFlt expression, and chorionic trophoblast apoptotic index in normal and preeclamptic pregnancies. Decidua from first (n=5) and second (n=4) trimester terminations and chorioamniotic membranes, containing decidua, from term deliveries (n=14), early-onset (≤ 34 weeks) (n=12), and late-onset (>34 weeks) (n=14) severe preeclampsia were evaluated. Immunohistochemistry for CD3, CD8, and FoxP3 was performed: CD8(+) and FoxP3(+) cells were calculated as a proportion of CD3(+) cells. Placental tissue was evaluated for villous hypermaturity and sFlt staining. Chorioamniotic membranes were evaluated, via TUNEL assay, for chorionic trophoblast apoptosis. Decidual Treg cells were seen to peak in second trimester and decrease with advancing gestational age and were lower in early-onset (0.46%) compared with late-onset severe preeclampsia (3.34%) and term pregnancies (5.21%). The proportion of CD8(+) cells was higher in cases of severe preeclampsia. Early-onset severe preeclamptic cases had the highest sFlt score, placental insufficiency score, and apoptotic index. Our data suggest that early-onset severe preeclampsia has a unique pathophysiology involving defective immunoregulatory pathways, potentially causing vascular and trophoblast damage at the implantation site.

Factors contributing to burnout among perfusionists in the United States

Introduction: As the job climate continues to change, many perfusionists are faced with high employee turnover rates, working longer hours, and increased stress related to more complex surgeries. Understanding the sources of professional burnout and stress may allow the formulation of a strategy to help prevent such negative outcomes. The purpose of this study was to determine the current level of stress and burnout among perfusionists.

Methods: A questionnaire was constructed with the use of SurveyMonkey®. Invitations requesting participation in the survey were distributed by electronic mail to members of PerfList and PerfMail. To assess burnout, components of the well-established Maslach Burnout Inventory (MBI) tool were used.

Results: At p<0.05, job demand variables such as stress level, conflict, call duties, hours worked, and case load were all shown to have a statistically significant relationship to burnout.

Conclusion: The study found that, among the various factors, job demands were the most likely culprit contributing to burnout. Stress level and conflict, in particular, had the strongest association to burnout.

Expression of Siglec-11 by human and chimpanzee ovarian stromal cells, with uniquely human ligands: implications for human ovarian physiology and pathology

Siglecs (Sialic acid-binding Immunoglobulin Superfamily Lectins) are cell surface signaling receptors of the I-type lectin group that recognize sialic acid-bearing glycans. CD33-related-Siglecs are a subset with expression primarily in cells of hematopoietic origin and functional relevance to immune reactions. Earlier we reported a human-specific gene conversion event that markedly changed the coding region for the extracellular domain of Siglec-11, associated with human-specific expression in microglia (Hayakawa T, Angata T, Lewis AL, Mikkelsen TS, Varki NM, Varki A. 2005. A human-specific gene in microglia. Science. 309:1693). Analyzing human gene microarrays to define new patterns of expression, we observed high levels of SIGLEC11 transcript in the ovary and adrenal cortex. Thus, we examined human and chimpanzee tissues using a well-characterized anti-Siglec-11 mouse monoclonal antibody. Although adrenal expression was variable and confined to infiltrating macrophages in capillaries, ovarian expression of Siglec-11 in both humans and chimpanzees was on fibroblasts, the first example of Siglec expression on mesenchyme-derived stromal cells. Cytokines from such ovarian stromal fibroblasts play important roles in follicle development and ovulation. Stable transfection of SIGLEC11 into a primary human ovarian stromal fibroblast cell line altered the secretion of growth-regulated oncogene α, interleukin (IL)-10, IL-7, transforming growth factor β1 and tumor necrosis factor-α, cytokines involved in ovarian physiology. Probing for Siglec-11 ligands revealed distinct and strong mast cell expression in human ovaries, contrasting to diffuse stromal ligands in chimpanzee ovaries. Interestingly, there was a trend of increased Siglec-11 expression in post-menopausal ovaries compared with pre-menopausal ones. Siglec-11 expression was also found on human ovarian stromal tumors and in polycystic ovarian syndrome, a human-specific disease. These results indicate potential roles for Siglec-11 in ovarian physiology and human evolution.

Association between genetic polymorphisms in fibroblast growth factor (FGF)1 and FGF2 and risk of endometriosis and adenomyosis in Chinese women

BACKGROUND

Angiogenesis appears to be an important event in the pathophysiology of endometriosis (EM) and adenomyosis. Two angiogenic factors, fibroblast growth factor (FGF) 1 and 2, play a central role in the initiation of angiogenesis. We investigated whether FGF1 -1385A/G and FGF2 754C/G polymorphisms are associated with a risk of developing EM and adenomyosis.

METHODS

Genotypes were analyzed by the PCR-restriction fragment length polymorphism method in two groups of women, of Han ethnicity in north China, aged 16-55 years: (1) 421 EM patients and 421 controls; (2) 269 adenomyosis patients and 269 controls.

RESULTS

There was no difference in genotype distribution of the FGF1 -1385A/G polymorphism between adenomyosis cases and controls (P > 0.05), but the frequency of the A allele in EM patients was lower than that in controls (P = 0.013). Genotype and allele frequencies of the FGF2 754C/C polymorphism were significantly different in both EM and adenomyosis cases versus control groups. Compared with C/C homozygotes, the G allele (C/G + G/G) was associated with a decreased susceptibility to developing EM [odds ratio (OR) = 0.575, 95% confidence interval (CI) = 0.387-0.854] and adenomyosis (OR = 0.577, 95% CI = 0.367-0.906). Combined genotype analysis of both polymorphisms also showed differences between cases versus controls (all P < 0.001).

CONCLUSIONS

Our study shows for the first time that the FGF2 754C/G polymorphism may be associated with a risk of developing EM and adenomyosis in north Chinese women. Carriers of the G allele in the FGF2 gene appear to be protected from these gynecological diseases. Further studies in other populations, and of other candidate genes, are now warranted.

Islet transplantation for brittle type 1 diabetes: the UIC protocol

This prospective phase 1/2 trial investigated the safety and reproducibility of allogeneic islet transplantation (Tx) in type I diabetic (T1DM) patients and tested a strategy to achieve insulin-independence with lower islet mass. Ten C-peptide negative T1DM subjects with hypoglycemic unawareness received 1-3 intraportal allogeneic islet Tx and were followed for 15 months. Four subjects (Group 1) received the Edmonton immunosuppression regimen (daclizumab, sirolimus, tacrolimus). Six subjects (Group 2) received the University of Illinois protocol (etanercept, exenatide and the Edmonton regimen). All subjects became insulin- independent. Group 1 received a mean total number of islets (EIN) of 1460 080 +/- 418 330 in 2 (n = 2) or 3 (n = 2) Tx, whereas Group 2 became insulin- independent after 1 Tx (537 495 +/- 190 968 EIN, p = 0.028). All Group 1 subjects remained insulin free through the follow-up. Two Group 2 subjects resumed insulin: one after immunosuppression reduction during an infectious complication, the other with exenatide intolerance. HbA1c reached normal range in both groups (6.5 +/- 0.6 at baseline to 5.6 +/- 0.5 after 2-3 Tx in Group 1 vs. 7.8 +/- 1.1 to 5.8 +/- 0.3 after 1 Tx in Group 2). HYPO scores markedly decreased in both groups. Combined treatment of etanercept and exenatide improves islet graft function and facilitates achievement of insulin-independence with less islets.

Interferon-gamma and cancer immunoediting

Over the last 12 yr, we have shown that interferon-gamma and lymphocytes collaborate to regulate tumor development in mice. Specifically, we found that the immune system not only prevents the growth of primary (carcinogen-induced and spontaneous) and transplanted tumors but also sculpts the immunogenicity of tumors that form. These observations led us to refine the old and controversial "cancer immunosurveillance" hypothesis of Burnet and Thomas into one that we termed cancer immunoediting that better emphasizes the paradoxical host-protective and tumor-sculpting roles of immunity on developing tumors. Our current work focuses on defining the molecular mechanisms that underlie cancer immunoediting and exploring the implications of this process for cancer immunotherapy.

Adeno-associated virus vector-mediated transgene integration into neurons and other nondividing cell targets

The site-specific integration of wild-type adeno-associated virus (wtAAV) into the human genome is a very attractive feature for the development of AAV-based gene therapy vectors. However, knowledge about integration of wtAAV, as well as currently configured recombinant AAV (rAAV) vectors, is limited. By using a modified Alu-PCR technique to amplify and sequence the vector-cellular junctions, we provide the first direct evidence both in vitro and in vivo of rAAV-mediated transgene integration in several types of nondividing cells, including neurons. This novel technique will be highly useful for further delineating the mechanisms underlying AAV-mediated integration, including issues of frequency, site preference, and DNA rearrangement in human as well as animal cells. Results from these studies should be beneficial for the development of the next generation of gene delivery vectors.