Citations

Abstract Multiple myeloma is a blood cancer that arises in the bone marrow from malignant plasma cells. Although treatments have dramatically improved during the last decade, multiple myeloma remains an incurable disease responsible for more than 10 000 deaths per year in the United States. CD137 is a costimulatory molecule expressed on activated T cells and NK cells. We recently established that agonist monoclonal antibodies (mAbs) against CD137 (clone 3H3) significantly reduce tumor burden and improve survival in a mouse model of multiple myeloma1. We found that anti-CD137 mAb therapeutic activity requires the presence of both CD8 T cells and NK cells but is independent of Fc receptors. Moreover, we observed increased numbers of T cells in the bone marrow of anti-CD137 mAb treated mice. CD8 T cells were increased while the percentage of Tregs was reduced. Thus, anti-CD137 mAbs protect mice against multiple myeloma by inducing potent NK cell and CD8 T cell responses. In the present study, we investigate further the therapeutic interest and the potential limitations of anti-CD137 mAbs. To this aim, we used multiple myeloma cell lines derived from Vk*MYC transgenic mice. Wild-type (WT) mice intravenously injected with Vk*MYC cells develop a disease very similar to human multiple myeloma. High percentages of malignant plasma cells are observed in the bone marrow and in the spleen 5 weeks after injection and disease progression can be followed by the level of serum gamma-globulin (M protein). We first observed that, although early anti-CD137 mAb treatment efficiently protected the mice against multiple myeloma, this treatment loses efficacy when given more than 3 weeks after Vk*MYC cell injection. Interestingly, CD4 cell depletion restores the efficacy of late anti-CD137 mAb treatment, indicating that Treg-mediated suppression may limit the therapeutic efficacy of anti-CD137 mAbs. In line with previous studies, we observed that NK cell numbers in the spleen are dramatically reduced 12 days after the initiation of anti-CD137 mAb treatment. NK cell numbers are also decreased in other organs including liver, lung and blood. Importantly, we found that NK cells are still poorly represented in the spleen 3 weeks after the last treatment with anti-CD137 mAbs. Finally, we observed that anti-CD137 mAb treatment induced T cell activation and increases T cell infiltration in the liver. Consistent with the cases of severe hepatitis observed in patients treated with anti-CD137 mAbs, we noted that some of anti-CD137 mAb treated mice that had survived multiple myeloma developed severe liver damage. Such liver damage could be observed more than 100 days after the last therapy with anti-CD137 mAbs. In conclusion, we report several side effects induced by anti-CD137 mAbs treatment that last long after the treatment has been interrupted. These results encourage being particularly careful when administrating this drug to patients. Our study demonstrates the utility of mouse models to investigate the anti-tumor benefits versus toxicity of immunotherapies. We are planning to use this approach to assess the therapeutic efficacy of anti-CD137 mAbs in combination with other treatments. We speculate that the prior reduction of tumor burden by chemotherapy or stem cell transplantation will allow better efficacy of anti-CD137 mAbs at lower doses. The use of mice injected with multiple myeloma cell lines will help determining which combination allows efficient anti-tumor responses at late multiple myeloma stages with limited toxicity. 1 Guillerey C*, De Andrade LF*, Vuckovic S, Miles K, Ngiow SF, Yong MCR, Teng MWL, Colonna M, Ritchie DS, Chesi M, Bergsagel PL, Hill GR, Smyth MJ*, Martinet L* Immunosurveillance and therapy of multiple myeloma is CD226-dependent; Journal of Clinical Investigation, May 1;125(5):2077-89. Citation Format: Camille Guillerey, Lucas Ferrari de Andrade, Slavica Vuckovic, David Ritchie, Marta Chesi, Leif Bergsagel, Geoffrey R. Hill, Ludovic Martinet, Mark J. Smyth. Anti-CD137 mAb therapy of multiple myeloma. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B155.

Abstract Our previous work has shown that in multiple hematologic and solid malignancies, an increased presence of CD14+HLA-DRlo/neg cells in the peripheral blood are associated with systemic immune suppression and poor prognosis. We have also demonstrated that glioblastoma and non-Hodgkin lymphoma tumor cells can convert healthy donor CD14+ cells into CD14+HLA-DRlo/neg. Thus, a critical step toward the generation of these immune suppressive cells is the recruitment of CD14+ monocytes to the tumor. In this study we investigated the mechanism for monocyte recruitment by lung cancer cell lines, the effect these lines have on the monocytes, and the effect the monocytes have on the tumor. Monocyte recruitment by H23, a human lung adenocarcinoma cell line, was studied using freshly isolated CD14+ cells and measured in real time with live cell imaging. Monocytes from 10 of 10 unique healthy donors robustly migrated towards H23 supernatant in a dose dependent fashion. H23 produces CCL2 at levels of 9160 ± 1615 pg/mL measured by ELISA in addition to elaborating the monocyte recruitment factors CXCL1 and IL-8 seen by cytokine array. A 2 day co-culture of H23 with monocytes from 17 of 18 unique healthy volunteers resulted in downregulated monocyte cell surface expression of HLA-DR by 49.7% ± 22.1%, a phenotype known to mediate both local and systemic immune suppression. Most importantly, monocytes had a positive effect on H23 survival under stress conditions. H23 continuously exposed to cisplatin in culture had improved survival when co-cultured with monocytes for 2 days prior to cisplatin exposure. After 6 days of low serum growth conditions, H23 survival and proliferation was bolstered by the presence of monocytes in culture resulting in a 2 fold greater number of viable H23 cells compared to H23 cultured in low serum without monocytes. These experiments have been repeated and showed that 3 of 4 additional human lung cancer cell lines demonstrated improved survival in low serum growth conditions when co-cultured with monocytes. In conclusion, we have demonstrated the active recruitment of monocytes by lung cancer cell lines, the transformation of the monocytes to an immune suppressive phenotype and the monocyte cancer cross-talk that results in improved tumor survival when exposed to the likely in vivo conditions of a nutrient poor environment or chemotherapy. Taken together these results suggest that the recruitment of monocytes may confer additional survival benefit in the tumor microenvironment beyond local immune suppression and angiogenesis. Citation Format: Erin Schenk, Allan Dietz. CD14+ monocyte recruitment, transformation and support of tumor survival in a lung cancer model. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A123.

Abstract Background: Entinostat, a class I HDAC inhibitor (HDACi), has shown promising activity in ENCORE 301, a randomized, placebo-controlled, phase II trial of entinostat + exemestane (EE) vs. exemestane + placebo (EP) in advanced hormone receptor-positive breast cancer progressed on nonsteroidal aromatase inhibitors. ENCORE 301 met the primary progression free survival endpoint and showed a median 8.3-month improvement in the overall survival (OS) exploratory endpoint for the EE arm. Emerging preclinical work suggests that entinostat has immunomodulatory effects and can eradicate modestly immunogenic mouse tumors in combination with immune checkpoint blockade agents via reduction of circulating myeloid-derived suppressor cells (MDSC). Based on these data, we conducted an analysis of immune subsets in blood samples from ENCORE 301 breast cancer patients. Method: Blood was collected from a subset of 49 patients (27 EE and 22 EP) representative of the 130 patients enrolled in ENCORE 301 on cycle 1 day 1 (C1D1; pre-treatment), C1D2, C1D8, and C1D15 for biomarker analysis. Of these, 34 patient samples (20 EE and 14 EP) were analyzed for circulating immune subsets. The percent change in subsets at C1D15 vs. baseline was assessed based on the following surface markers: Lin-MDSC (lin; CD3, CD19, CD56)-HLA-DR-CD11b+CD33+), granulocytic MDSC (CD14-CD11b+CD33+), monocytic MDSC (Lin-HLA-DR-CD11b+CD33+CD14+), immature MDSC (Lin-HLA-DR-CD11b+CD33+CD14-), CD8+ T-cells (CD4-CD8+), Foxp3-CD4+ T-cells (CD8-CD4+Foxp3-), and Tregs (CD4+CD8-CD25hiFoxp3+). Monocytes were analyzed for three populations: CD14+, CD14+HLA-DRhi, and CD14+HLA-DRlow/negative. In addition, PD-1, CTLA-4, and TIM-3 were measured on T-cell subsets, and CD40 was measured on MDSCs. Results: In line with preclinical data, we observed a significant reduction in granulocytic MDSC (-14.67% vs. +20.56%, p 0.029) and monocytic MDSC (-62.3% vs. +1.97%, p 0.002) in EE. Entinostat did not alter immature MDSC levels (-20.9% vs. -15.0%, p 0.93) suggesting a downstream effect of entinostat on MDSC subsets. Interestingly, CD40, a costimulatory receptor required for MDSC-mediated immune suppression was significantly down-regulated in all MDSC subsets except granulocytic MDSC where a downward trend was observed. Entinostat did not significantly impact the ratio of CD8+ T-cells per CD4+ T-cells or per Tregs or alter expression of CTLA4, PD-1, or TIM3 on T-cell subsets. Reduced expression of HLA-DR on monocytes has been associated with poor prognosis in cancer. Consistent with entinostat-mediated immunomodulatory effects, a significant increase in the number of HLA-DR+ monocytes (34.1% vs. -11.38%, p 0.0004) and level of HLA-DR expression on monocytes (16.3% vs. -4.7%; p 0.015) was observed. Conclusion: Data with entinostat combined with exemestane in ENCORE 301 provide the first evidence of HDACi-mediated reduction of immunosuppressive MDSCs and increased immunocompetent CD14+HLA-DRhi monocytes in patients. These findings may explain the improved OS seen with EE in ENCORE 301 and provide strong rationale for planned combination studies of entinostat with immune checkpoint blockade agents. Citation Format: Peter Ordentlich, Min-Jung Lee, Yusuke Tomita, Sunmin Lee, Saori Tomita, Scott Cruickshank, Saranya Chumsri, Jane B. Trepel. Epigenetic immune modulation by entinostat in breast cancer: Correlative analysis of ENCORE 301 trial. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A030.

Germline mutations in the DNA base excision repair gene MUTYH are known to increase a carrier's risk of colorectal cancer. However, the risks of other (extracolonic) cancers for MUTYH mutation carriers are not well defined. We identified 266 probands (91% Caucasians) with a MUTYH mutation (41 biallelic and 225 monoallelic) from the Colon Cancer Family Registry. Mutation status, sex, age and histories of cancer from their 1,903 first‐ and 3,255 second‐degree relatives were analyzed using modified segregation analysis conditioned on the ascertainment criteria. Compared with incidences for the general population, hazard ratios (HRs) (95% confidence intervals [CIs]) for biallelic MUTYH mutation carriers were: urinary bladder cancer 19 (3.7–97) and ovarian cancer 17 (2.4–115). The HRs (95% CI) for monoallelic MUTYH mutation carriers were: gastric cancer 9.3 (6.7–13); hepatobiliary cancer 4.5 (2.7–7.5); endometrial cancer 2.1 (1.1–3.9) and breast cancer 1.4 (1.0–2.0). There was no evidence for an increased risk of cancers at the other sites examined (brain, pancreas, kidney or prostate). Based on the USA population incidences, the estimated cumulative risks (95% CI) to age 70 years for biallelic mutation carriers were: bladder cancer 25% (5–77%) for males and 8% (2–33%) for females and ovarian cancer 14% (2–65%). The cumulative risks (95% CI) for monoallelic mutation carriers were: gastric cancer 5% (4–7%) for males and 2.3% (1.7–3.3%) for females; hepatobiliary cancer 3% (2–5%) for males and 1.4% (0.8–2.3%) for females; endometrial cancer 3% (2%–6%) and breast cancer 11% (8–16%). These unbiased estimates of both relative and absolute risks of extracolonic cancers for people, mostly Caucasians, with MUTYH mutations will be important for their clinical management.

ABSTRACT Measles is a highly contagious, acute viral illness. Immune cells within the airways are likely first targets of infection, and these cells traffic measles virus (MeV) to lymph nodes for amplification and subsequent systemic dissemination. Infected immune cells are thought to return MeV to the airways; however, the mechanisms responsible for virus transfer to pulmonary epithelial cells are poorly understood. To investigate this process, we collected blood from human donors and generated primary myeloid cells, specifically, monocyte-derived macrophages (MDMs) and dendritic cells (DCs). MDMs and DCs were infected with MeV and then applied to primary cultures of well-differentiated airway epithelial cells from human donors (HAE). Consistent with previous results obtained with free virus, infected MDMs or DCs were incapable of transferring MeV to HAE when applied to the apical surface. Likewise, infected MDMs or DCs applied to the basolateral surface of HAE grown on small-pore (0.4-μm) support membranes did not transfer virus. In contrast, infected MDMs and DCs applied to the basolateral surface of HAE grown on large-pore (3.0-μm) membranes successfully transferred MeV. Confocal microscopy demonstrated that MDMs and DCs are capable of penetrating large-pore membranes but not small-pore membranes. Further, by using a nectin-4 blocking antibody or recombinant MeV unable to enter cells through nectin-4, we demonstrated formally that transfer from immune cells to HAE occurs in a nectin-4-dependent manner. Thus, both infected MDMs and DCs rely on cell-to-cell contacts and nectin-4 to efficiently deliver MeV to the basolateral surface of HAE. IMPORTANCE Measles virus spreads rapidly and efficiently in human airway epithelial cells. This rapid spread is based on cell-to-cell contact rather than on particle release and reentry. Here we posit that MeV transfer from infected immune cells to epithelial cells also occurs by cell-to-cell contact rather than through cell-free particles. In addition, we sought to determine which immune cells transfer MeV infectivity to the human airway epithelium. Our studies are based on two types of human primary cells: (i) myeloid cells generated from donated blood and (ii) well-differentiated airway epithelial cells derived from donor lungs. We show that different types of myeloid cells, i.e., monocyte-derived macrophages and dendritic cells, transfer infection to airway epithelial cells. Furthermore, cell-to-cell contact is an important component of successful MeV transfer. Our studies elucidate a mechanism by which the most contagious human respiratory virus is delivered to the airway epithelium.