Publications by authors named "Susheela Tridandapani"

104 Publications

Activation of plasmacytoid dendritic cells promotes AML-cell fratricide.

Oncotarget 2021 Apr 27;12(9):878-890. Epub 2021 Apr 27.

Department of Internal Medicine, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA.

Acute myeloid leukemia (AML) is characterized by the proliferation of immature myeloid blasts and a suppressed immune state. Interferons have been previously shown to aid in the clearance of AML cells. Type I interferons are produced primarily by plasmacytoid dendritic cells (pDCs). However, these cells exist in a quiescent state in AML. Because pDCs express TLR 7-9, we hypothesized that the TLR7/8 agonist R848 would be able to reprogram them toward a more active, IFN-producing phenotype. Consistent with this notion, we found that R848-treated pDCs from patients produced significantly elevated levels of IFNβ. In addition, they showed increased expression of the immune-stimulatory receptor CD40. We next tested whether IFNβ would influence antibody-mediated fratricide among AML cells, as our recent work showed that AML cells could undergo cell-to cell killing in the presence of the CD38 antibody daratumumab. We found that IFNβ treatment led to a significant, IRF9-dependent increase in CD38 expression and a subsequent increase in daratumumab-mediated cytotoxicity and decreased colony formation. These findings suggest that the tolerogenic phenotype of pDCs in AML can be reversed, and also demonstrate a possible means of enhancing endogenous Type I IFN production that would promote daratumumab-mediated clearance of AML cells.
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http://dx.doi.org/10.18632/oncotarget.27949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092344PMC
April 2021

Activation of the Intracellular Pattern Recognition Receptor NOD2 Promotes Acute Myeloid Leukemia (AML) Cell Apoptosis and Provides a Survival Advantage in an Animal Model of AML.

J Immunol 2020 04 24;204(7):1988-1997. Epub 2020 Feb 24.

Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, OH 43210;

TLRs, a family of membrane-bound pattern recognition receptors found on innate immune cells, have been well studied in the context of cancer therapy. Activation of these receptors has been shown to induce inflammatory anticancer events, including differentiation and apoptosis, across a wide variety of malignancies. In contrast, intracellular pattern recognition receptors such as NOD-like receptors have been minimally studied. NOD2 is a member of the NOD-like receptor family that initiates inflammatory signaling in response to the bacterial motif muramyl dipeptide. In this study, we examined the influence of NOD2 in human acute myeloid leukemia (AML) cells, demonstrating that IFN-γ treatment upregulated the expression of NOD2 signaling pathway members SLC15A3 and SLC15A4, downstream signaling kinase RIPK2, and the NOD2 receptor itself. This priming allowed for effective induction of caspase-1-dependent cell death upon treatment with muramyl tripeptide phosphatidylethanolamine (MTP-PE), a synthetic ligand for NOD2. Furthermore, the combination of MTP-PE and IFN-γ on AML blasts generated an inflammatory cytokine profile and activated NK cells. In a murine model of AML, dual treatment with MTP-PE and IFN-γ led to a significant increase in mature CD27 CD11b NK cells as well as a significant reduction in disease burden and extended survival. These results suggest that NOD2 activation, primed by IFN-γ, may provide a novel therapeutic option for AML.
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http://dx.doi.org/10.4049/jimmunol.1900885DOI Listing
April 2020

CD31 Acts as a Checkpoint Molecule and Is Modulated by FcγR-Mediated Signaling in Monocytes.

J Immunol 2019 12 15;203(12):3216-3224. Epub 2019 Nov 15.

Division of Hematology, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210;

Monocytes and macrophages express FcγR that engage IgG immune complexes such as Ab-opsonized pathogens or cancer cells to destroy them by various mechanisms, including phagocytosis. FcγR-mediated phagocytosis is regulated by the concerted actions of activating FcγR and inhibitory receptors, such as FcγRIIb and SIRPα. In this study, we report that another ITIM-containing receptor, PECAM1/CD31, regulates FcγR function and is itself regulated by FcγR activation. First, quantitative RT-PCR and flow cytometry analyses revealed that human monocyte FcγR activation leads to a significant downregulation of CD31 expression, both at the message level and at surface expression, mainly mediated through FcγRIIa. Interestingly, the kinetics of downregulation between the two varied, with surface expression reducing earlier than the message. Experiments to analyze the mechanism behind this discrepancy revealed that the loss of surface expression was because of internalization, which depended predominantly on the PI3 kinase pathway and was independent of FcγR internalization. Finally, functional analyses showed that the downregulation of CD31 expression in monocytes by small interfering RNA enhanced FcγR-mediated phagocytic ability but have little effect on cytokine production. Together, these results suggest that CD31 acts as a checkpoint receptor that could be targeted to enhance FcγR functions in Ab-mediated therapies.
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http://dx.doi.org/10.4049/jimmunol.1900059DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6904527PMC
December 2019

Evidence for interaction of the NLRP3 inflammasome and Bruton's tyrosine kinase in tumor-associated macrophages: implications for myeloid cell production of interleukin-1beta.

Oncoimmunology 2019;8(11):1659704. Epub 2019 Sep 5.

Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA.

An inflammatory microenvironment has been shown to play an important role in the growth and metastasis of tumors. The NLRP3 inflammasome is a multi-protein complex of the innate immune system that is responsible for the production of the potent inflammatory cytokine IL-1β. Tumor- associated macrophages (TAM) are an expanded population of immune cells found in the tumor microenvironment that can promote the initiation and metastasis of tumor cells. Their presence has been correlated with disease burden, highlighting the therapeutic potential of targeting this population. However, to date clinically relevant pharmacologic strategies to target TAM remain elusive. Here, we show that generated TAM harbor NLRP3 inflammasome components and produce IL-1β. Ibrutinib, an irreversible inhibitor of Bruton's tyrosine kinase (BTK), is in clinical use for the treatment of B- cell malignancies. We report that BTK is expressed by human generated TAM and murine macrophages and that it physically associates with the NLRP3 inflammasome. Furthermore, ibrutinib is able to inhibit BTK phosphorylation in TAM generated . Treatment of TAM with ibrutinib significantly impaired the ability of these cells to produce IL-1β. The present study provides evidence that BTK physically associates with the NLRP3 inflammasome and that inhibition of BTK with ibrutinib can impair the production of IL-1β by generated TAM. Thus, ibrutinib could potentially be of clinical use in abrogating inflammation-associated cancer progression and the immune-suppressive effects of myeloid cells within the tumor microenvironment.
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http://dx.doi.org/10.1080/2162402X.2019.1659704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6791459PMC
September 2019

A Phase I/II Trial of Cetuximab in Combination with Interleukin-12 Administered to Patients with Unresectable Primary or Recurrent Head and Neck Squamous Cell Carcinoma.

Clin Cancer Res 2019 08 29;25(16):4955-4965. Epub 2019 May 29.

Division of Surgical Oncology, Department of Surgery, The Ohio State University, Columbus, Ohio.

Purpose: mAbs including cetuximab can induce antibody-dependent cellular cytotoxicity (ADCC) and cytokine production mediated via innate immune cells with the ability to recognize mAb-coated tumors. Preclinical modeling has shown that costimulation of natural killer (NK) cells via the Fc receptor and the IL12 receptor promotes NK-cell-mediated ADCC and production of cytokines.

Patients And Methods: This phase I/II trial evaluated the combination of cetuximab with IL12 for the treatment of EGFR-expressing head and neck cancer. Treatment consisted of cetuximab 500 mg/m i.v. every 2 weeks with either 0.2 mcg/kg or 0.3 mcg/kg IL12 s.c. on days 2 and 5 of the 2-week cycle, beginning with cycle 2. Correlative studies from blood draws obtained prior to treatment and during therapy included measurement of ADCC, serum cytokine, and chemokine analysis, determination of NK cell FcγRIIIa polymorphisms, and an analysis of myeloid-derived suppressor cell (MDSC) frequency in peripheral blood.

Results: The combination of cetuximab and IL12 was well tolerated. No clinical responses were observed, however, 48% of patients exhibited prolonged progression-free survival (PFS; average of 6.5 months). Compared with patients that did not exhibit clinical benefit, patients with PFS >100 days exhibited increased ADCC as therapy continued compared with baseline, greater production of IFNγ, IP-10, and TNFα at the beginning of cycle 8 compared with baseline values and had a predominance of monocytic MDSCs versus granulocytic MDSCs prior to therapy.

Conclusions: Further investigation of IL12 as an immunomodulatory agent in combination with cetuximab in head and neck squamous cell carcinoma is warranted.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-2108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6697573PMC
August 2019

Generation of monocyte-derived tumor-associated macrophages using tumor-conditioned media provides a novel method to study tumor-associated macrophages in vitro.

J Immunother Cancer 2019 05 28;7(1):140. Epub 2019 May 28.

Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.

Background: Tumor-associated macrophages (TAM) are expanded and exhibit tumor-promoting properties within the tumor microenvironment. Current methods to study TAM have not been replicated across cancer types and often do not include exogenous growth factors from the tumor, a key factor in TAM differentiation in vivo.

Methods: In this study, an in vitro method to generate monocyte- derived TAM using tumor- conditioned media (TCM) and a cytokine cocktail containing IL-4, IL-10, and M-CSF was utilized to study the phenotype, morphology, and function of TAM across multiple cancer types. TCM was generated from two breast cancer cell lines and an Epstein-Barr virus-positive lymphoma cell line. The properties of in vitro generated TAM were compared to in vitro generated M1 and M2- like macrophages and TAM isolated from patients with cancer.

Results: TAM generated in this fashion displayed an increase in CD163/CD206 co-expression compared to M2- like macrophages (87 and 36%, respectively). TAM generated in vitro exhibited increased transcript levels of the functional markers IL-6, IL-10, CCL2, c-Myc, iNOS, and arginase compared to in vitro generated M2-like macrophages. Functionally, in vitro generated TAM inhibited the proliferation of T cells (47% decrease from M1-like macrophages) and the production of IFN-γ by natural killer cells was inhibited (44%) when co-cultured with TAM. Furthermore, in vitro generated TAM secreted soluble factors that promote the growth and survival of tumor cells.

Conclusions: Limited access to patient TAM highlights the need for methods to generate TAM in vitro. Our data confirm that monocyte-derived TAM can be generated reliably using TCM plus the cytokine cocktail of IL-4, IL-10, and M-CSF. Given the ability of TAM to inhibit immune cell function, continued study of methods to deplete or deactivate TAM in the setting of cancer are warranted.
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http://dx.doi.org/10.1186/s40425-019-0622-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6540573PMC
May 2019

Neuroblastoma RAS viral oncogene homolog mRNA is differentially spliced to give five distinct isoforms: implications for melanoma therapy.

Melanoma Res 2019 10;29(5):491-500

Department of Cutaneous Oncology, Moffitt Cancer Center, Tampa, Florida.

Neuroblastoma RAS viral oncogene homolog is a commonly mutated oncogene in melanoma, and therapeutic targeting of neuroblastoma RAS viral oncogene homolog has proven difficult. We characterized the expression and phenotypic functions of five recently discovered splice isoforms of neuroblastoma RAS viral oncogene homolog in melanoma. Canonical neuroblastoma RAS viral oncogene homolog (isoform-1) was expressed to the highest degree and its expression was significantly increased in melanoma metastases compared to primary lesions. Isoform-5 expression in metastases showed a significant, positive correlation with survival and tumours over-expressing isoform-5 had significantly decreased growth in a xenograft model. In contrast, over-expression of any isoform resulted in enhanced proliferation, and invasiveness was increased with over-expression of isoform-1 or isoform-2. Downstream signalling analysis indicated that the isoforms signalled differentially through the mitogen-activated protein kinase and PI3K pathways and A375 cells over-expressing isoform-2 or isoform-5 showed resistance to vemurafenib treatment in vitro. The neuroblastoma RAS viral oncogene homolog isoforms appear to play varying roles in melanoma phenotype and could potentially serve as biomarkers for therapeutic response and disease prognosis.
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http://dx.doi.org/10.1097/CMR.0000000000000623DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7088457PMC
October 2019

Anti-BAFF-R antibody VAY-736 demonstrates promising preclinical activity in CLL and enhances effectiveness of ibrutinib.

Blood Adv 2019 02;3(3):447-460

Division of Hematology, Department of Internal Medicine, College of Medicine and OSU Comprehensive Cancer Center.

The Bruton tyrosine kinase inhibitor (BTKi) ibrutinib has transformed chronic lymphocytic leukemia (CLL) therapy but requires continuous administration. These factors have spurred interest in combination treatments. Unlike with chemotherapy, CD20-directed antibody therapy has not improved the outcome of BTKi treatment. Whereas CD20 antigen density on CLL cells decreases during ibrutinib treatment, the B-cell activating factor (BAFF) and its receptor (BAFF-R) remain elevated. Furthermore, BAFF signaling via noncanonical NF-κB remains elevated with BTKi treatment. Blocking BAFF interaction with BAFF-R by using VAY-736, a humanized defucosylated engineered antibody directed against BAFF-R, antagonized BAFF-mediated apoptosis protection and signaling at the population and single-cell levels in CLL cells. Furthermore, VAY-736 showed superior antibody-dependent cellular cytotoxicity compared with CD20- and CD52-directed antibodies used in CLL. VAY-736 exhibited in vivo activity as a monotherapy and, when combined with ibrutinib, produced prolonged survival compared with either therapy alone. The in vivo activity of VAY-736 is dependent upon immunoreceptor tyrosine-based activation motif (ITAM)-mediated activation of effector cells as shown by using an ITAM-deficient mouse model. Collectively, our findings support targeting the BAFF signaling pathway with VAY-736 to more effectively treat CLL as a single agent and in combination with ibrutinib.
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http://dx.doi.org/10.1182/bloodadvances.2018025684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6373734PMC
February 2019

Anti-leukemic effects of all-trans retinoic acid in combination with Daratumumab in acute myeloid leukemia.

Int Immunol 2018 07;30(8):375-383

Department of Internal Medicine, The Ohio State University, Columbus, OH, USA.

Acute myeloid leukemia (AML) remains a significant health problem, with poor outcomes despite chemotherapy and bone marrow transplants. Although one form of AML, acute promyelocytic leukemia (APL), is successfully treated with all-trans retinoic acid (ATRA), this drug is seemingly ineffective against all other forms of AML. Here, we show that ATRA up-regulates CD38 expression on AML blasts to sufficient levels that promote antibody-mediated fratricide following the addition of anti-CD38 daratumumab (DARA). The combination of ATRA plus DARA induced Fc-dependent conjugate formation and cytotoxicity among AML blasts in vitro. Combination treatment also led to reduction in tumor volume and resulted in increased overall survival in murine engraftment models of AML. These results suggest that, although ATRA does not induce differentiation of non-APL, it may be effective as a therapy in conjunction with DARA.
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http://dx.doi.org/10.1093/intimm/dxy040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6059202PMC
July 2018

Author Correction: Nitric oxide mediated inhibition of antigen presentation from DCs to CD4 T cells in cancer and measurement of STAT1 nitration.

Sci Rep 2018 Mar 6;8(1):4203. Epub 2018 Mar 6.

Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, United States.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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http://dx.doi.org/10.1038/s41598-018-21306-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840347PMC
March 2018

Nitric Oxide Production by Myeloid-Derived Suppressor Cells Plays a Role in Impairing Fc Receptor-Mediated Natural Killer Cell Function.

Clin Cancer Res 2018 04 23;24(8):1891-1904. Epub 2018 Jan 23.

Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

mAbs are used to treat solid and hematologic malignancies and work in part through Fc receptors (FcRs) on natural killer cells (NK). However, FcR-mediated functions of NK cells from patients with cancer are significantly impaired. Identifying the mechanisms of this dysfunction and impaired response to mAb therapy could lead to combination therapies and enhance mAb therapy. Cocultures of autologous NK cells and MDSC from patients with cancer were used to study the effect of myeloid-derived suppressor cells (MDSCs) on NK-cell FcR-mediated functions including antibody-dependent cellular cytotoxicity, cytokine production, and signal transduction Mouse breast cancer models were utilized to study the effect of MDSCs on antibody therapy and test the efficacy of combination therapies including a mAb and an MDSC-targeting agent. MDSCs from patients with cancer were found to significantly inhibit NK-cell FcR-mediated functions including antibody-dependent cellular cytotoxicity, cytokine production, and signal transduction in a contact-independent manner. In addition, adoptive transfer of MDSCs abolished the efficacy of mAb therapy in a mouse model of pancreatic cancer. Inhibition of iNOS restored NK-cell functions and signal transduction. Finally, nonspecific elimination of MDSCs or inhibition of iNOS significantly improved the efficacy of mAb therapy in a mouse model of breast cancer. MDSCs antagonize NK-cell FcR-mediated function and signal transduction leading to impaired response to mAb therapy in part through nitric oxide production. Thus, elimination of MDSCs or inhibition of nitric oxide production offers a strategy to improve mAb therapy. .
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http://dx.doi.org/10.1158/1078-0432.CCR-17-0691DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7184799PMC
April 2018

Nitric oxide mediated inhibition of antigen presentation from DCs to CD4 T cells in cancer and measurement of STAT1 nitration.

Sci Rep 2017 11 13;7(1):15424. Epub 2017 Nov 13.

Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, United States.

Myeloid derived suppressor cells (MDSC) produce nitric oxide (NO) and inhibit dendritic cell (DC) immune responses in cancer. DCs present cancer cell antigens to CD4 T cells through Jak-STAT signal transduction. In this study, NO donors (SNAP and DETA-NONOate) inhibited DC antigen presentation. As expected, MDSC isolated from peripheral blood mononuclear cells (PBMC) from cancer patients produced high NO levels. We hypothesized that NO producing MDSC in tumor-bearing hosts would inhibit DC antigen presentation. Antigen presentation from DCs to CD4 T cells (T cell receptor transgenic OT-II) was measured via a [H]-thymidine incorporation proliferation assay. MDSC from melanoma tumor models decreased the levels of proliferation more than pancreatic cancer derived MDSC. T cell proliferation was restored when MDSC were treated with inhibitors of inducible nitric oxide synthase (L-NAME and NCX-4016). A NO donor inhibited OT II T cell receptor recognition of OT II specific tetramers, thus serving as a direct measure of NO inhibition of antigen presentation. Our group has previously demonstrated that STAT1 nitration also mediates MDSC inhibitory effects on immune cells. Therefore, a novel liquid chromatography-tandem mass spectrometry assay demonstrated that nitration of the STAT1-Tyr701 occurs in PBMC derived from both pancreatic cancer and melanoma patients.
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http://dx.doi.org/10.1038/s41598-017-14970-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684213PMC
November 2017

Identification of NRAS isoform 2 overexpression as a mechanism facilitating BRAF inhibitor resistance in malignant melanoma.

Proc Natl Acad Sci U S A 2017 09 21;114(36):9629-9634. Epub 2017 Aug 21.

Division of Surgical Oncology, The Ohio State University, Columbus, OH 43210

Activating mutations in BRAF are found in 50% of melanomas and although treatment with BRAF inhibitors (BRAFi) is effective, resistance often develops. We now show that recently discovered NRAS isoform 2 is up-regulated in the setting of BRAF inhibitor resistance in melanoma, in both cell lines and patient tumor tissues. When isoform 2 was overexpressed in BRAF mutant melanoma cell lines, melanoma cell proliferation and in vivo tumor growth were significantly increased in the presence of BRAFi treatment. shRNA-mediated knockdown of isoform 2 in BRAFi resistant cells restored sensitivity to BRAFi compared with controls. Signaling analysis indicated decreased mitogen-activated protein kinase (MAPK) pathway signaling and increased phosphoinositol-3-kinase (PI3K) pathway signaling in isoform 2 overexpressing cells compared with isoform 1 overexpressing cells. Immunoprecipitation of isoform 2 validated a binding affinity of this isoform to both PI3K and BRAF/RAF1. The addition of an AKT inhibitor to BRAFi treatment resulted in a partial restoration of BRAFi sensitivity in cells expressing high levels of isoform 2. NRAS isoform 2 may contribute to resistance to BRAFi by facilitating PI3K pathway activation.
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http://dx.doi.org/10.1073/pnas.1704371114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5594655PMC
September 2017

Active hexose-correlated compound enhances extrinsic-pathway-mediated apoptosis of Acute Myeloid Leukemic cells.

PLoS One 2017 20;12(7):e0181729. Epub 2017 Jul 20.

Department of Internal Medicine, The Ohio State University, Columbus, Ohio, United States of America.

Active Hexose Correlated Compound (AHCC) has been shown to have many immunostimulatory and anti-cancer activities in mice and in humans. As a natural product, AHCC has potential to create safer adjuvant therapies in cancer patients. Acute Myeloid Leukemia (AML) is the least curable and second-most common leukemia in adults. AML is especially terminal to those over 60 years old, where median survival is only 5 to 10 months, due to inability to receive intensive chemotherapy. Hence, the purpose of this study was to investigate the effects of AHCC on AML cells both in vitro and in vivo. Results showed that AHCC induced Caspase-3-dependent apoptosis in AML cell lines as well as in primary AML leukopheresis samples. Additionally, AHCC induced Caspase-8 cleavage as well as Fas and TRAIL upregulation, suggesting involvement of the extrinsic apoptotic pathway. In contrast, monocytes from healthy donors showed suppressed Caspase-3 cleavage and lower cell death. When tested in a murine engraftment model of AML, AHCC led to significantly increased survival time and decreased blast counts. These results uncover a mechanism by which AHCC leads to AML-cell specific death, and also lend support for the further investigation of AHCC as a potential adjuvant for the treatment of AML.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181729PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5519206PMC
September 2017

MICA-Expressing Monocytes Enhance Natural Killer Cell Fc Receptor-Mediated Antitumor Functions.

Cancer Immunol Res 2017 09 19;5(9):778-789. Epub 2017 Jul 19.

The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.

Natural killer (NK) cells are large granular lymphocytes that promote the antitumor response via communication with other cell types in the tumor microenvironment. Previously, we have shown that NK cells secrete a profile of immune stimulatory factors (e.g., IFNγ, MIP-1α, and TNFα) in response to dual stimulation with the combination of antibody (Ab)-coated tumor cells and cytokines, such as IL12. We now demonstrate that this response is enhanced in the presence of autologous monocytes. Monocyte enhancement of NK cell activity was dependent on cell-to-cell contact as determined by a Transwell assay. It was hypothesized that NK cell effector functions against Ab-coated tumor cells were enhanced via binding of MICA on monocytes to NK cell NKG2D receptors. Strategies to block MICA-NKG2D interactions resulted in reductions in IFNγ production. Depletion of monocytes resulted in decreased IFNγ production by murine NK cells upon exposure to Ab-coated tumor cells. In mice receiving trastuzumab and IL12 therapy, monocyte depletion resulted in significantly greater tumor growth in comparison to mock-depleted controls ( < 0.05). These data suggest that NK cell-monocyte interactions enhance NK cell antitumor activity in the setting of monoclonal Ab therapy for cancer. .
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http://dx.doi.org/10.1158/2326-6066.CIR-16-0005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5581690PMC
September 2017

Fluorescent nanodiamonds engage innate immune effector cells: A potential vehicle for targeted anti-tumor immunotherapy.

Nanomedicine 2017 04 18;13(3):909-920. Epub 2016 Dec 18.

The Arthur G. James Comprehensive Cancer Center and Solove Research Institute, The Ohio State University, Columbus, OH, USA; Department of Surgery, The Ohio State University, Columbus, OH, USA. Electronic address:

Fluorescent nanodiamonds (FNDs) are nontoxic, infinitely photostable, and emit fluorescence in the near infrared region. Natural killer (NK) cells and monocytes are part of the innate immune system and are crucial to the control of carcinogenesis. FND-mediated stimulation of these cells may serve as a strategy to enhance anti-tumor activity. FNDs were fabricated with a diameter of 70±28 nm. Innate immune cell FND uptake, viability, surface marker expression, and cytokine production were evaluated in vitro. Evaluation of fluorescence emission from the FNDs was conducted in an animal model. In vitro results demonstrated that treatment of immune cells with FNDs resulted in significant dose-dependent FND uptake, no compromise in cell viability, and immune cell activation. FNDs were visualized in an animal model. Hence, FNDs may serve as novel agents with "track and trace" capabilities to stimulate innate immune cell anti-tumor responses, especially as FNDs are amenable to surface-conjugation with immunomodulatory molecules.
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http://dx.doi.org/10.1016/j.nano.2016.12.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5405740PMC
April 2017

Interferon-γ Promotes Antibody-mediated Fratricide of Acute Myeloid Leukemia Cells.

J Biol Chem 2016 Dec 25;291(49):25656-25666. Epub 2016 Oct 25.

From the Medical Scientist Training Program,

Acute myeloid leukemia (AML) is characterized by the proliferation of immature myeloid lineage blasts. Due to its heterogeneity and to the high rate of acquired drug resistance and relapse, new treatment strategies are needed. Here, we demonstrate that IFNγ promotes AML blasts to act as effector cells within the context of antibody therapy. Treatment with IFNγ drove AML blasts toward a more differentiated state, wherein they showed increased expression of the M1-related markers HLA-DR and CD86, as well as of FcγRI, which mediates effector responses to therapeutic antibodies. Importantly, IFNγ was able to up-regulate CD38, the target of the therapeutic antibody daratumumab. Because the antigen (CD38) and effector receptor (FcγRI) were both simultaneously up-regulated on the AML blasts, we tested whether IFNγ treatment of the AML cell lines THP-1 and MV4-11 could stimulate them to target one another after the addition of daratumumab. Results showed that IFNγ significantly increased daratumumab-mediated cytotoxicity, as measured both by Cr release and lactate dehydrogenase release assays. We also found that the combination of IFNγ and activation of FcγR led to the release of granzyme B by AML cells. Finally, using a murine NSG model of subcutaneous AML, we found that treatment with IFNγ plus daratumumab significantly attenuated tumor growth. Taken together, these studies show a novel mechanism of daratumumab-mediated killing and a possible new therapeutic strategy for AML.
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http://dx.doi.org/10.1074/jbc.M116.753145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5207262PMC
December 2016

Targeting myeloid-derived suppressor cells using a novel adenosine monophosphate-activated protein kinase (AMPK) activator.

Oncoimmunology 2016;5(9):e1214787. Epub 2016 Jul 25.

Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA; Division of Surgical Oncology, Department of Surgery and Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of early myeloid cells that accumulate in the blood and tumors of patients with cancer. MDSC play a critical role during tumor evasion and promote immune suppression through variety of mechanisms, such as the generation of reactive oxygen and nitrogen species (ROS and RNS) and cytokines. AMPactivated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that regulates energy homeostasis and metabolic stress. However, the role of AMPK in the regulation of MDSC function remains largely unexplored. This study was designed to investigate whether treatment of MDSC with OSU-53, a PPAR-inactive derivative that stimulates AMPK kinase, can modulate MDSC function. Our results demonstrate that OSU-53 treatment increases the phosphorylation of AMPK, significantly reduces nitric oxide production, inhibits MDSC migration, and reduces the levels of IL-6 in murine MDSC cell line (MSC2 cells). OSU53 treatment mitigated the immune suppressive functions of murine MDSC, promoting T-cell proliferation. Although OSU-53 had a modest effect on tumor growth in mice inoculated with EMT-6 cells, importantly, administration of OSU53 significantly ( < 0.05) reduced the levels of MDSC in the spleens and tumors. Furthermore, mouse MDSC from EMT-6 tumor-bearing mice and human MDSC isolated from melanoma patients treated with OSU-53 showed a significant reduction in the expression of immune suppressive genes iNOS and arginase. In summary, these results demonstrate a novel role of AMPK in the regulation of MDSC functions and provide a rationale of combining OSU-53 with immune checkpoint inhibitors to augment their response in cancer patients.
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http://dx.doi.org/10.1080/2162402X.2016.1214787DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5048767PMC
July 2016

A phase I study of recombinant (r) vaccinia-CEA(6D)-TRICOM and rFowlpox-CEA(6D)-TRICOM vaccines with GM-CSF and IFN-α-2b in patients with CEA-expressing carcinomas.

Cancer Immunol Immunother 2016 11 31;65(11):1353-1364. Epub 2016 Aug 31.

Division of Surgical Oncology, The Ohio State University, N924 Doan Hall, 410 W. 10th Avenue, Columbus, OH, 43210, USA.

Prime-boost vaccination with recombinant (r) vaccinia(V)-CEA(6D)-TRICOM (triad of co-stimulatory molecules B7.1, ICAM-1 and LFA-3) and rFowlpox(F)-CEA(6D)-TRICOM infect antigen-presenting cells and direct expression of co-stimulatory molecules. We hypothesized that co-administration of vaccine with GM-CSF and interferon alpha (IFN-α) would have efficacy in CEA-expressing cancers. Patients with CEA-expressing cancers received the rV-CEA(6D)-TRICOM vaccine subcutaneously (s.c.) on day 1 followed by GM-CSF s.c. to the injection site on days 1-4. In Cycle 1, patients received thrice weekly s.c. injections of IFN-α-2b the week after rV-CEA(6D)-TRICOM. In Cycles 2-4, patients received thrice weekly s.c. injections of IFN-α-2b the same week that rF-CEA(6D)-TRICOM was given. The first cohort received no IFN followed by dose escalation of IFN-α in subsequent cohorts. Thirty-three patients were accrued (mean 59.8 years). Grade 3 toxicities included fatigue and hyperglycemia. Grade 4-5 adverse events (unrelated to treatment) were confusion (1), elevated aspartate transaminase (AST)/alanine transaminase (ALT) (1), and sudden death (1). No patients had a partial response, and eight patients exhibited stable disease of ≥3 months. Median progression-free survival and overall survival (OS) were 1.8 and 6.3 months, respectively. Significantly higher serum CD27 levels were observed after vaccine therapy (p = 0.006 post 1-2 cycles, p = 0.003 post 3 cycles, p = 0.03 post 4-7 cycles) and 42 % of patients assayed developed CEA-specific T cell responses. Pre-treatment levels of myeloid-derived suppressor cells correlated with overall survival (p = 0.04). Administration of IFN-α led to significantly increased OS (p = 0.02) compared to vaccine alone. While the vaccine regimen produced no clinical responses, IFN-α administration was associated with improved survival.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5071149PMC
http://dx.doi.org/10.1007/s00262-016-1893-7DOI Listing
November 2016

IL-21 Enhances Natural Killer Cell Response to Cetuximab-Coated Pancreatic Tumor Cells.

Clin Cancer Res 2017 Jan 19;23(2):489-502. Epub 2016 Jul 19.

Division of Surgical Oncology, Department of Surgery, The Ohio State University, Columbus, Ohio.

Purpose: Alternative strategies to EGFR blockage by mAbs is necessary to improve the efficacy of therapy in patients with locally advanced or metastatic pancreatic cancer. One such strategy includes the use of NK cells to clear cetuximab-coated tumor cells, as need for novel therapeutic approaches to enhance the efficacy of cetuximab is evident. We show that IL-21 enhances NK cell-mediated effector functions against cetuximab-coated pancreatic tumor cells irrespective of KRAS mutation status.

Experimental Design: NK cells from normal donors or donors with pancreatic cancer were used to assess ADCC, IFN-γ release, and T-cell chemotaxis toward human pancreatic cancer cell lines. The in vivo efficacy of IL-21 in combination with cetuximab was evaluated in a subcutaneous and intraperitoneal model of pancreatic cancer.

Results: NK cell lysis of cetuximab-coated wild-type and mutant kras pancreatic cancer cell lines were significantly higher following NK cell IL-21 treatment. In response to cetuximab-coated pancreatic tumor cells, IL-21-treated NK cells secreted significantly higher levels of IFN-γ and chemokines, increased chemotaxis of T cells, and enhanced NK cell signal transduction via activation of ERK and STAT1. Treatment of mice bearing subcutaneous or intraperitoneal EGFR-positive pancreatic tumor xenografts with mIL-21 and cetuximab led to significant inhibition of tumor growth, a result further enhanced by the addition of gemcitabine.

Conclusions: These results suggest that cetuximab treatment in combination with IL-21 adjuvant therapy in patients with EGFR-positive pancreatic cancer results in significant NK cell activation, irrespective of KRAS mutation status, and may be a potential therapeutic strategy. Clin Cancer Res; 23(2); 489-502. ©2016 AACR.
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http://dx.doi.org/10.1158/1078-0432.CCR-16-0004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241232PMC
January 2017

Insulin and the phosphatidylinositol 3-kinase signaling pathway regulate Ribonuclease 7 expression in the human urinary tract.

Kidney Int 2016 09 9;90(3):568-79. Epub 2016 Jul 9.

Center for Clinical and Translational Research, Department of Pediatrics, The Research Institute at Nationwide Children's, Columbus, Ohio, USA; Division of Nephrology, Department of Pediatrics, Nationwide Children's, Columbus, Ohio, USA. Electronic address:

Diabetes mellitus is a systemic disease associated with a deficiency of insulin production or action. Diabetic patients have an increased susceptibility to infection with the urinary tract being the most common site. Recent studies suggest that Ribonuclease 7 (RNase 7) is a potent antimicrobial peptide that plays an important role in protecting the urinary tract from bacterial insult. Because the impact of diabetes on RNase 7 expression and function are unknown, we investigated the effects of insulin on RNase 7 using human urine specimens. The urinary RNase 7 concentrations were measured in healthy control patients and insulin-deficient type 1 diabetics before and after starting insulin therapy. Compared with controls, diabetic patients had suppressed urinary RNase 7 concentrations, which increased with insulin. Using primary human urothelial cells, the mechanisms by which insulin stimulates RNase 7 synthesis were next explored. Insulin induced RNase 7 production via the phosphatidylinositide 3-kinase signaling pathway (PI3K/AKT) to shield urothelial cells from uropathogenic E. coli. In contrast, uropathogenic E. coli suppressed PI3K/AKT activity and RNase 7 production. Thus, insulin and PI3K/AKT signaling are essential for RNase 7 expression and increased infection risks in diabetic patients may be secondary to suppressed RNase 7 production. Our data may provide unique insight into novel urinary tract infection therapeutic strategies in at-risk populations.
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http://dx.doi.org/10.1016/j.kint.2016.04.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5576060PMC
September 2016

Reprogramming Nurse-like Cells with Interferon γ to Interrupt Chronic Lymphocytic Leukemia Cell Survival.

J Biol Chem 2016 Jul 13;291(27):14356-14362. Epub 2016 May 13.

Department of Internal Medicine, Ohio State University, Columbus, Ohio 43210. Electronic address:

Nurse-like cells (NLCs) play a central role in chronic lymphocytic leukemia (CLL) because they promote the survival and proliferation of CLL cells. NLCs are derived from the monocyte lineage and are driven toward their phenotype via contact-dependent and -independent signals from CLL cells. Because of the central role of NLCs in promoting disease, new strategies to eliminate or reprogram them are needed. Successful reprogramming may be of extra benefit because NLCs express Fcγ receptors (FcγRs) and thus could act as effector cells within the context of antibody therapy. IFNγ is known to promote the polarization of macrophages toward an M1-like state that is no longer tumor-supportive. In an effort to reprogram the phenotype of NLCs, we found that IFNγ up-regulated the M1-related markers CD86 and HLA-DR as well as FcγRIa. This corresponded to enhanced FcγR-mediated cytokine production as well as rituximab-mediated phagocytosis of CLL cells. In addition, IFNγ down-regulated the expression of CD31, resulting in withdrawal of the survival advantage on CLL cells. These results suggest that IFNγ can re-educate NLCs and shift them toward an effector-like state and that therapies promoting local IFNγ production may be effective adjuvants for antibody therapy in CLL.
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http://dx.doi.org/10.1074/jbc.M116.723551DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4933188PMC
July 2016

Myeloid-Derived Suppressor Cells Express Bruton's Tyrosine Kinase and Can Be Depleted in Tumor-Bearing Hosts by Ibrutinib Treatment.

Cancer Res 2016 04 15;76(8):2125-36. Epub 2016 Feb 15.

Division of Surgical Oncology, Department of Surgery and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of immature myeloid cells that expand in tumor-bearing hosts in response to soluble factors produced by tumor and stromal cells. MDSC expansion has been linked to loss of immune effector cell function and reduced efficacy of immune-based cancer therapies, highlighting the MDSC population as an attractive therapeutic target. Ibrutinib, an irreversible inhibitor of Bruton's tyrosine kinase (BTK) and IL2-inducible T-cell kinase (ITK), is in clinical use for the treatment of B-cell malignancies. Here, we report that BTK is expressed by murine and human MDSCs, and that ibrutinib is able to inhibit BTK phosphorylation in these cells. Treatment of MDSCs with ibrutinib significantly impaired nitric oxide production and cell migration. In addition, ibrutinib inhibited in vitro generation of human MDSCs and reduced mRNA expression of indolamine 2,3-dioxygenase, an immunosuppressive factor. Treatment of mice bearing EMT6 mammary tumors with ibrutinib resulted in reduced frequency of MDSCs in both the spleen and tumor. Ibrutinib treatment also resulted in a significant reduction of MDSCs in wild-type mice bearing B16F10 melanoma tumors, but not in X-linked immunodeficiency mice (XID) harboring a BTK mutation, suggesting that BTK inhibition plays an important role in the observed reduction of MDSCs in vivo Finally, ibrutinib significantly enhanced the efficacy of anti-PD-L1 (CD274) therapy in a murine breast cancer model. Together, these results demonstrate that ibrutinib modulates MDSC function and generation, revealing a potential strategy for enhancing immune-based therapies in solid malignancies. Cancer Res; 76(8); 2125-36. ©2016 AACR.
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http://dx.doi.org/10.1158/0008-5472.CAN-15-1490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873459PMC
April 2016

NK Cell-Mediated Antitumor Effects of a Folate-Conjugated Immunoglobulin Are Enhanced by Cytokines.

Cancer Immunol Res 2016 Apr 10;4(4):323-336. Epub 2016 Feb 10.

Department of Biomedical Sciences Graduate Program, College of Medicine, The Ohio State University, Columbus, OH.

Optimally effective antitumor therapies would not only activate immune effector cells but also engage them at the tumor. Folate conjugated to immunoglobulin (F-IgG) could direct innate immune cells with Fc receptors to folate receptor-expressing cancer cells. F-IgG bound to human KB and HeLa cells, as well as murine L1210JF, a folate receptor (FR)-overexpressing cancer cell line, as determined by flow cytometry. Recognition of F-IgG by natural killer (NK) cell Fc receptors led to phosphorylation of the ERK transcription factor and increased NK cell expression of CD69. Lysis of KB tumor cells by NK cells increased by about 5-fold after treatment with F-IgG, an effect synergistically enhanced by treatment with IL2, IL12, IL15, or IL21 (P< 0.001). F-IgG also enhanced the lysis of chronic lymphocytic leukemia cells by autologous NK cells. NK cells significantly increased production of IFNγ, MIP-1α, and RANTES in response to F-IgG-coated KB target cells in the presence of the NK cell-activating cytokine IL12, and these coculture supernatants induced significant T-cell chemotaxis (P< 0.001). F-IgG-coated targets also stimulated FcR-mediated monocyte effector functions. Studies in a murine leukemia model confirmed the intratumoral localization and antitumor activity of F-IgG, as well as enhancement of its effects by IL12 (P =0.05). The antitumor effect of this combination was dependent on NK cells and led to decreased tumor cell proliferation in vivo Thus, F-IgG can induce an immune response against FR-positive tumor cells that is mediated by NK cells and can be augmented by cytokine therapy.
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http://dx.doi.org/10.1158/2326-6066.CIR-15-0168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818694PMC
April 2016

Toll-like Receptor 4 Ligands Down-regulate Fcγ Receptor IIb (FcγRIIb) via MARCH3 Protein-mediated Ubiquitination.

J Biol Chem 2016 Feb 22;291(8):3895-904. Epub 2015 Dec 22.

Department of Internal Medicine, and

Monocytes and macrophages are critical for the effectiveness of monoclonal antibody therapy. Responses to antibody-coated tumor cells are largely mediated by Fcγ receptors (FcγRs), which become activated upon binding to immune complexes. FcγRIIb is an inhibitory FcγR that negatively regulates these responses, and it is expressed on monocytes and macrophages. Therefore, deletion or down-regulation of this receptor may substantially enhance therapeutic outcomes. Here we screened a panel of Toll-like receptor (TLR) agonists and found that those selective for TLR4 and TLR8 could significantly down-regulate the expression of FcγRIIb. Upon further examination, we found that treatment of monocytes with TLR4 agonists could lead to the ubiquitination of FcγRIIb protein. A search of our earlier microarray database of monocytes activated with the TLR7/8 agonist R-848 (in which FcγRIIb was down-regulated) revealed an up-regulation of membrane-associated ring finger (C3HC4) 3 (MARCH3), an E3 ubiquitin ligase. Therefore, we tested whether LPS treatment could up-regulate MARCH3 in monocytes and whether this E3 ligase was involved with LPS-mediated FcγRIIb down-regulation. The results showed that LPS activation of TLR4 significantly increased MARCH3 expression and that siRNA against MARCH3 prevented the decrease in FcγRIIb following LPS treatment. These data suggest that activation of TLR4 on monocytes can induce a rapid down-regulation of FcγRIIb protein and that this involves ubiquitination.
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http://dx.doi.org/10.1074/jbc.M115.701151DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4759169PMC
February 2016

Analysis of the Effects of the Bruton's tyrosine kinase (Btk) Inhibitor Ibrutinib on Monocyte Fcγ Receptor (FcγR) Function.

J Biol Chem 2016 Feb 1;291(6):3043-52. Epub 2015 Dec 1.

the Department of Internal Medicine and

The irreversible Bruton's tyrosine kinase (Btk) inhibitor ibrutinib has shown efficacy against B-cell tumors such as chronic lymphocytic leukemia and B-cell non-Hodgkin lymphoma. Fcγ receptors (FcγR) on immune cells such as macrophages play an important role in tumor-specific antibody-mediated immune responses, but many such responses involve Btk. Here we tested the effects of ibrutinib on FcγR-mediated activities in monocytes. We found that ibrutinib did not affect monocyte FcγR-mediated phagocytosis, even at concentrations higher than those achieved physiologically, but suppressed FcγR-mediated cytokine production. We confirmed these findings in macrophages from Xid mice in which Btk signaling is defective. Because calcium flux is a major event downstream of Btk, we tested whether it was involved in phagocytosis. The results showed that blocking intracellular calcium flux decreased FcγR-mediated cytokine production but not phagocytosis. To verify this, we measured activation of the GTPase Rac, which is responsible for actin polymerization. Results showed that ibrutinib did not inhibit Rac activation, nor did the calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester). We next asked whether the effect of ibrutinib on monocyte FcγR-mediated cytokine production could be rescued by IFNγ priming because NK cells produce IFNγ in response to antibody therapy. Pretreatment of monocytes with IFNγ abrogated the effects of ibrutinib on FcγR-mediated cytokine production, suggesting that IFNγ priming could overcome this Btk inhibition. Furthermore, in monocyte-natural killer cell co-cultures, ibrutinib did not inhibit FcγR-mediated cytokine production despite doing so in single cultures. These results suggest that combining ibrutinib with monoclonal antibody therapy could enhance chronic lymphocytic leukemia cell killing without affecting macrophage effector function.
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http://dx.doi.org/10.1074/jbc.M115.687251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742765PMC
February 2016

The Raf Kinase Inhibitor Sorafenib Inhibits JAK-STAT Signal Transduction in Human Immune Cells.

J Immunol 2015 Sep 3;195(5):1995-2005. Epub 2015 Aug 3.

Department of Surgery, The Ohio State University, Columbus, OH 43210; Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210; Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus, OH 43210

Sorafenib is an oral multikinase inhibitor that was originally developed as a Raf kinase inhibitor. We hypothesized that sorafenib would also have inhibitory effects on cytokine signaling pathways in immune cells. PBMCs from normal donors were treated with varying concentrations of sorafenib and stimulated with IFN-α or IL-2. Phosphorylation of STAT1 and STAT5 was measured by flow cytometry and confirmed by immunoblot analysis. Changes in IFN-α- and IL-2-stimulated gene expression were measured by quantitative PCR, and changes in cytokine production were evaluated by ELISA. Cryopreserved PBMCs were obtained from cancer patients before and after receiving 400 mg sorafenib twice daily. Patient PBMCs were thawed, stimulated with IL-2 or IFN-α, and evaluated for phosphorylation of STAT1 and STAT5. Pretreatment of PBMCs with 10 μM sorafenib decreased STAT1 and STAT5 phosphorylation after treatment with IFN-α or IL-2. This inhibitory effect was observed in PBMCs from healthy donors over a range of concentrations of sorafenib (5-20 μM), IL-2 (2-24 nM), and IFN-α (10(1)-10(6) U/ml). This effect was observed in immune cell subsets, including T cells, B cells, NK cells, regulatory T cells, and myeloid-derived suppressor cells. Pretreatment with sorafenib also inhibited PBMC expression of IFN-α- and IL-2-regulated genes and inhibited NK cell production of IFN-γ, RANTES, MIP1-α, and MIG in response to IFN-α stimulation. PBMCs from patients receiving sorafenib therapy showed decreased responsiveness to IL-2 and IFN-α treatment. Sorafenib is a Raf kinase inhibitor that could have off-target effects on cytokine-induced signal transduction in immune effector cells.
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http://dx.doi.org/10.4049/jimmunol.1400084DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4546911PMC
September 2015

Granzyme B expression is enhanced in human monocytes by TLR8 agonists and contributes to antibody-dependent cellular cytotoxicity.

J Immunol 2015 Mar 9;194(6):2786-95. Epub 2015 Feb 9.

Department of Internal Medicine, The Ohio State University, Columbus, OH 43210; Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210;

FcγRs are critical mediators of mAb cancer therapies, because they drive cytotoxic processes upon binding of effector cells to opsonized targets. Along with NK cells, monocytes are also known to destroy Ab-coated targets via Ab-dependent cellular cytotoxicity (ADCC). However, the precise mechanisms by which monocytes carry out this function have remained elusive. In this article, we show that human monocytes produce the protease granzyme B upon both FcγR and TLR8 activation. Treatment with TLR8 agonists elicited granzyme B and also enhanced FcγR-mediated granzyme B production in an additive fashion. Furthermore, monocyte-mediated ADCC against cetuximab-coated tumor targets was enhanced by TLR8 agonist treatment, and this enhancement of ADCC required granzyme B. Hence we have identified granzyme B as an important mediator of FcγR function in human monocytes and have uncovered another mechanism by which TLR8 agonists may enhance FcγR-based therapies.
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http://dx.doi.org/10.4049/jimmunol.1402316DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4355383PMC
March 2015

Role of cysteine-rich 61 protein (CCN1) in macrophage-mediated oncolytic herpes simplex virus clearance.

Mol Ther 2014 Sep 4;22(9):1678-87. Epub 2014 Jun 4.

Department of Neurological Surgery, Dardinger Laboratory for Neuro-oncology and Neurosciences, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.

Glioblastoma is a devastating disease, and there is an urgent need to develop novel therapies, such as oncolytic HSV1 (OV) to effectively target tumor cells. OV therapy depends on tumor-specific replication leading to destruction of neoplastic tissues. Host responses that curtail virus replication limit its efficacy in vivo. We have previously shown that cysteine-rich 61 protein (CCN1) activates a type 1 IFN antiviral defense response in glioblastoma cells. Incorporating TCGA data, we found CCN1 expression to be a negative prognostic factor for glioblastoma patients. Based on this, we used neutralizing antibodies against CCN1 to investigate its effect on OV therapy. Use of an anti-CCN1 antibody in mice bearing glioblastomas treated with OV led to enhanced virus expression along with reduced immune cell infiltration. OV-induced CCN1 increases macrophage migration toward infected glioblastoma cells by directly binding macrophages and also by enhancing the proinflammatory activation of macrophages inducing MCP-1 expression in glioblastoma cells. Activation of macrophages by CCN1 also increases viral clearance. Neutralization of integrin αMβ2 reversed CCN1-induced macrophage activation and migration, and reduced MCP-1 expression by glioblastoma cells. Our findings reveal that CCN1 plays a novel role in pathogen clearance; increasing macrophage infiltration and activation resulting in increased virus clearance in tumors.
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http://dx.doi.org/10.1038/mt.2014.101DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4435480PMC
September 2014

Virulent Type A Francisella tularensis actively suppresses cytokine responses in human monocytes.

Front Cell Infect Microbiol 2014 10;4:45. Epub 2014 Apr 10.

Center for Microbial Interface Biology, The Ohio State University Columbus, OH, USA ; Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, The Ohio State University Columbus, OH, USA.

Background: Human monocyte inflammatory responses differ between virulent and attenuated Francisella infection.

Results: A mixed infection model showed that the virulent F. tularensis Schu S4 can attenuate inflammatory cytokine responses to the less virulent F. novicida in human monocytes.

Conclusion: F. tularensis dampens inflammatory response by an active process.

Significance: This suppression may contribute to enhanced pathogenicity of F. tularensis. Francisella tularensis is a Gram-negative facultative bacterium that can cause the disease tularemia, even upon exposure to low numbers of bacteria. One critical characteristic of Francisella is its ability to dampen or subvert the host immune response. Previous work has shown that monocytes infected with highly virulent F. tularensis subsp. tularensis strain Schu S4 responded with a general pattern of quantitatively reduced pro-inflammatory signaling pathway genes and cytokine production in comparison to those infected with the less virulent related F. novicida. However, it has been unclear whether the virulent Schu S4 was merely evading or actively suppressing monocyte responses. By using mixed infection assays with F. tularensis and F. novicida, we show that F. tularensis actively suppresses monocyte pro-inflammatory responses. Additional experiments show that this suppression occurs in a dose-dependent manner and is dependent upon the viability of F. tularensis. Importantly, F. tularensis was able to suppress pro-inflammatory responses to earlier infections with F. novicida. These results lend support that F. tularensis actively dampens human monocyte responses and this likely contributes to its enhanced pathogenicity.
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http://dx.doi.org/10.3389/fcimb.2014.00045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3988375PMC
January 2015