Citations

AbstractB lymphopoiesis in bone marrow (BM) is critical for maintaining a diverse peripheral B cell pool to fight infection and establish lifelong immunity. The generation of immature B cells is reduced in Flt3‐ligand (FL‐/‐) mice leading to deficiencies in splenic B cells. Here, we sought to understand the cellular basis of the spleen B cell deficiency in FL‐/‐ mice. Significant reductions in transitional (TS) and follicular (FO) B cells were found in FL‐/‐ mice, and increased frequencies, but not absolute numbers, of marginal zone (MZ) B cells. BAFF‐R expression on splenic B cells and serum levels of B cell activating factor (BAFF) was comparable to wildtype (WT) mice. Mixed BM chimeras revealed that the reductions in TS and FO B cells were cell extrinsic. FL administration into FL‐/‐ mice restored the deficiency in TS B cells and normalized the MZ compartment. Ki67 analysis revealed a significant decrease in the proliferative capacity of TS B cells in FL‐/‐ mice. A Bcl2 transgene did not rescue TS cells in FL‐/‐ mice, uncoupling FL‐deficiency to Bcl2‐dependent survival pathways. Upregulation of CD1d expression and adoptive transfer experiments suggested MZ skewing in FL‐/‐ mice. These findings support an integral role for Flt3 signaling in peripheral B cell maturation.

Abstract Background: Mammographic density (MD) is a strong breast cancer risk factor. We previously reported associations of percent mammographic density (PMD) with larger and node-positive tumors across all ages, and estrogen receptor (ER)–negative status among women ages <55 years. To provide insight into these associations, we examined the components of PMD [dense area (DA) and nondense area (NDA)] with breast cancer subtypes. Methods: Data were pooled from six studies including 4,095 breast cancers and 8,558 controls. DA and NDA were assessed from digitized film-screen mammograms and standardized across studies. Breast cancer odds by density phenotypes and age according to histopathologic characteristics and receptor status were calculated using polytomous logistic regression. Results: DA was associated with increased breast cancer risk [OR for quartiles: 0.65, 1.00 (Ref), 1.22, 1.55; Ptrend <0.001] and NDA was associated with decreased risk [ORs for quartiles: 1.39, 1.00 (Ref), 0.88, 0.72; Ptrend <0.001] across all ages and invasive tumor characteristics. There were significant trends in the magnitude of associations of both DA and NDA with breast cancer by increasing tumor size (Ptrend < 0.001) but no differences by nodal status. Among women <55 years, DA was more strongly associated with increased risk of ER+ versus ER− tumors (Phet = 0.02), while NDA was more strongly associated with decreased risk of ER− versus ER+ tumors (Phet = 0.03). Conclusions: DA and NDA have differential associations with ER+ versus ER− tumors that vary by age. Impact: DA and NDA are important to consider when developing age- and subtype-specific risk models. Cancer Epidemiol Biomarkers Prev; 24(5); 798–809. ©2015 AACR.

Purpose To develop a genomic signature that predicts benefit from trastuzumab in human epidermal growth factor receptor 2–positive breast cancer. Patients and Methods DASL technology was used to quantify mRNA in samples from 1,282 patients enrolled onto the Combination Chemotherapy With or Without Trastuzumab in Treating Women With Breast Cancer (North Central Cancer Treatment Group N9831 [NCCTG-N9831]) adjuvant trastuzumab trial. Cox proportional hazard ratios (HRs), adjusted for significant clinicopathologic risk factors, were used to determine the association of each gene with relapse-free survival (RFS) for 433 patients who received chemotherapy alone (arm A) and 849 patients who received chemotherapy plus trastuzumab (arms B and C). Network and pathway analyses were used to identify key biologic processes linked to RFS. The signature was built by using a voting scheme. Results Network and functional ontology analyses suggested that increased RFS was linked to a subset of immune function genes. A voting scheme model was used to define immune gene enrichment based on the expression of any nine or more of 14 immune function genes at or above the 0.40 quantile for the population. This model was used to identify immune gene–enriched tumors in arm A and arms B and C. Immune gene enrichment was linked to increased RFS in arms B and C (HR, 0.35; 95% CI, 0.22 to 0.55; P < .001), whereas arm B and C patients who did not exhibit immune gene enrichment did not benefit from trastuzumab (HR, 0.89; 95% CI, 0.62 to 1.28; P = .53). Enriched immune function gene expression as defined by our predictive signature was not associated with increased RFS in arm A (HR, 0.90; 95% CI, 0.60 to 1.37; P = .64). Conclusion Increased expression of a subset of immune function genes may provide a means of predicting benefit from adjuvant trastuzumab.

Abstract Recent thymic emigrants (RTEs) must undergo phenotypic and functional maturation to become long-lived mature naive T cells. In CD4-cre NKAP conditional knockout mice, NKAP-deficient RTEs fail to complete T cell maturation. In this study, we demonstrate that NKAP-deficient immature RTEs do not undergo apoptosis, but are eliminated by complement. C3, C4, and C1q are bound to NKAP-deficient peripheral T cells, demonstrating activation of the classical arm of the complement pathway. As thymocytes mature and exit to the periphery, they increase sialic acid incorporation into cell surface glycans. This is essential to peripheral lymphocyte survival, as stripping sialic acid with neuraminidase leads to the binding of natural IgM and complement fixation. NKAP-deficient T cells have a defect in sialylation on cell surface glycans, leading to IgM recruitment. We demonstrate that the defect in sialylation is due to aberrant α2,8-linked sialylation, and the expression of three genes (ST8sia1, ST8sia4, and ST8sia6) that mediate α2,8 sialylation are downregulated in NKAP-defcient RTEs. The maturation of peripheral NKAP-deficient T cells is partially rescued in a C3-deficient environment. Thus, sialylation during T cell maturation is critical to protect immature RTEs from complement in the periphery.

Abstract Although myeloid-derived suppressor cells (MDSCs) are well known for their immunosuppressive function in several pathological conditions, the role of MDSCs in hepatitis B virus infection remains obscure. In this study, we investigated the frequency and function of MDSCs in the peripheral blood and liver of 91 chronic hepatitis B (CHB) patients. A higher percentage of MDSCs, defined as CD14+HLA-DR−/low, was detected in peripheral blood of CHB patients than that of the healthy controls. Moreover, high expression of programmed death 1 (PD-1) and secretion of IL-10 in this population were determined. The frequency of MDSCs was positively correlated with serum viral load, but it was negatively correlated with liver inflammatory injury. These cells were also abundant in liver tissue of CHB patients and were related to necroinflammatory activity. Furthermore, we found that these cells could suppress hepatitis B virus–specific CD8+ T cell response, including reduced proliferation and IFN-γ production, and inhibit degranulation of CD8+ T cells, including reduced production of granzyme B and perforin. Importantly, PD-1–induced IL-10 production by MDSCs was responsible for the suppressive activity. To our knowledge, for the first time our study proved that CD14+HLA-DR–/lowPD-1+ MDSCs in CHB patients contribute to an inadequate immune response against the virus and lead to chronic infection, which represents a potential target for therapeutic intervention.

Abstract Mesenchymal stem cells (MSC) represent a new tool for delivery of therapeutic agents to cancer sites because of their strong tropism toward tumors. IL15 has demonstrated a potent antitumor activity in various animal models as well as clinical trials. However, because of its short half-life, effective therapeutic effects usually require a high dose, which often results in undesired side effects; thus, new strategies for overcoming this disadvantage are needed. In this study, human MSCs were isolated from umbilical cord blood as delivery vehicles and transduced with lentivirus vector expressing murine IL15 (MSC-IL15). In vitro assays of lymphocyte activation and proliferation demonstrated that IL15 produced by MSCs was biofunctional. In syngeneic mice bearing Pan02 pancreatic tumors, systemic administration of MSC-IL15 significantly inhibited tumor growth and prolonged the survival of tumor-bearing mice, which were associated with tumor cell apoptosis, and natural killer (NK)– and T-cell accumulation. Furthermore, we confirmed that MSC-IL15 could migrate toward tumor and secreted IL15 in tumor-specific sites. Depletion of NK and CD8+ T cells abolished the antitumor activity of MSC-IL15, suggesting that NK and CD8+ T cells play a key role for MSC-IL15–mediated effect. Interestingly, cured mice after MSC-IL15 treatment were resistant to Pan02 pancreatic tumor rechallenge, and adoptive transfer of lymphocytes from cured mice also could cause rejection of Pan02 tumor inoculation in naïve mice, indicating that MSC-IL15 induced tumor-specific T-cell immune memory response. Overall, these data support that MSCs producing IL15 might represent an innovative strategy for therapy of pancreatic tumor. Mol Cancer Ther; 13(8); 2127–37. ©2014 AACR.

Abstract To reveal biologic mechanisms underlying clinical outcome of high-grade serous (HGS) epithelial ovarian carcinomas (EOC), we evaluated the association between tumor epigenetic changes and time to recurrence (TTR). We assessed methylation at approximately 450,000 genome-wide CpGs in tumors of 337 Mayo Clinic (Rochester, MN) patients. Semi-supervised clustering of discovery (n = 168) and validation (n = 169) sets was used to determine clinically relevant methylation classes. Clustering identified two methylation classes based on 60 informative CpGs, which differed in TTR in the validation set [R vs. L class, P = 2.9 × 10−3, HR = 0.52; 95% confidence interval (CI), 0.34–0.80]. Follow-up analyses considered genome-wide tumor mRNA expression (n = 104) and CD8 T-cell infiltration (n = 89) in patient subsets. Hypomethylation of CpGs located in 6p21.3 in the R class associated with cis upregulation of genes enriched in immune response processes (TAP1, PSMB8, PSMB9, HLA-DQB1, HLA-DQB2, HLA-DMA, and HLA-DOA), increased CD8 T-cell tumor infiltration (P = 7.6 × 10−5), and trans-regulation of genes in immune-related pathways (P = 1.6 × 10−32). This is the most comprehensive assessment of clinical outcomes with regard to epithelial ovarian carcinoma tumor methylation to date. Collectively, these results suggest that an epigenetically mediated immune response is a predictor of recurrence and, possibly, treatment response for HGS EOC. Cancer Res; 74(11); 3084–91. ©2014 AACR.

Aims To explore the immunohistochemical utility of proliferating cell nuclear antigen (PCNA), insulin-like growth factor 2 (IGF2) and clusterin in the distinction between malignant and benign liver nodular lesions. Methods Immunohistochemical stains for PCNA, IGF2 and clusterin were performed on 284 liver nodular lesions, including 33 hepatocellular adenomas (HCA), 40 focal nodular hyperplasias (FNH), 77 large regenerative nodules (LRN) and 134 hepatocellular carcinomas (HCC). Results Strong and diffuse nuclear PCNA immunoreactivity was observed in 103 (77%) HCCs but in only 2 (6%) HCAs. None of the FNH and LRN cases showed a strong and diffuse staining pattern. All HCAs, 95% of FNHs and 92% of LRNs showed cytoplasmic IGF2 expression, with a strong staining observed in 70% of HCAs, 20% of FNHs and 30% of LRNs. This was in marked contrast to that observed in HCCs, where 66% of HCCs demonstrated a weak and focal/patchy immunostaining pattern and another 25% showed no detectable IGF2 immunoreactivity. In comparison with their adjacent non-lesional hepatocytes, 75% of HCCs showed decreased IGF2 expression. However, decreased IGF2 expression was not evident in HCAs, FNHs and LRNs. Cytoplasmic staining for clusterin was seen in both benign and malignant nodular lesions. However, an enhanced and exaggerated pericanalicular staining pattern was observed in 75% of HCCs, which was not demonstrated in HCAs, FNHs and LRNs. Conclusions PCNA, IGF2 and clusterin show unique immunostaining characteristics in HCCs, which can be useful adjuncts to other currently available markers to aid in the distinction of HCC from benign liver nodular lesions.