Cetuximab-activated natural killer and dendritic cells collaborate to trigger tumor antigen-specific T-cell immunity in head and neck cancer patients.

PURPOSE: Tumor antigen-specific monoclonal antibodies (mAb) block oncogenic signaling and induce Fcγ receptor (FcγR)-mediated cytotoxicity. However, the role of CD8(+) CTL and FcγR in initiating innate and adaptive immune responses in mAb-treated human patients with cancer is still emerging. EXPERIMENTAL DESIGN: FcγRIIIa codon 158 polymorphism was correlated with survival in 107 cetuximab-treated patients with head and neck cancer (HNC). Flow cytometry was carried out to quantify EGF receptor (EGFR)-specific T cells in cetuximab-treated patients with HNC. The effect of cetuximab on natural killer (NK) cell, dendritic cell (DC), and T-cell activation was measured using IFN-γ release assays and flow cytometry. RESULTS: FcγRIIIa polymorphism did not predict clinical outcome in cetuximab-treated patients with HNC; however, elevated circulating EGFR(853-861)-specific CD8(+) T cells were found in cetuximab-treated patients with HNC (P < 0.005). Cetuximab promoted EGFR-specific cellular immunity through the interaction of EGFR(+) tumor cells and FcγRIIIa on NK cells but not on the polymorphism per se. Cetuximab-activated NK cells induced IFN-γ-dependent expression of DC maturation markers, antigen processing machinery components such as TAP-1/2 and T-helper cell (T(H)1) chemokines through NKG2D/MICA binding. Cetuximab initiated adaptive immune responses via NK cell-induced DC maturation, which enhanced cross-presentation to CTL specific for EGFR as well as another tumor antigen, MAGE-3. CONCLUSION: Cetuximab-activated NK cells promote DC maturation and CD8(+) T-cell priming, leading to tumor antigen spreading and TH1 cytokine release through "NK-DC cross-talk." FcγRIIIa polymorphism did not predict clinical response to cetuximab but was necessary for NK-DC interaction and mAb-induced cross-presentation. EGFR-specific T cells in cetuximab-treated patients with HNC may contribute to clinical response.

Endoscopic endonasal pituitary surgery: impact of surgical education on operation length and patient morbidity.

Objectives To determine the difference in operative times and associated complications for cases performed solely by attending-level surgeons versus cases assisted by surgeons-in-training for endoscopic endonasal pituitary surgeries. Design Retrospective chart review. Setting Tertiary-care academic medical center. Participants A total of 228 patients having undergone endoscopic endonasal pituitary surgery from 2005 to 2011. Main Outcome Measure Duration of surgery comparing attending only (AO) and trainee-assisted (TA) surgeries. Results Thirty-seven (19%) of 198 cases were identified as AO surgeries, the remaining 161 (81%) were TA. Operative times (minutes) for the AO group were significantly shorter than the TA group (149.1 ± 54.8 vs 219.5 ± 83.7, p < 0.001). The AO group had fewer intraoperative cerebrospinal fluid leaks (30% vs 39%, p = 0.318), decreased estimated blood loss (408 mL vs 523 mL, p = 0.176), fewer postoperative complications (27% vs 37%, p = 0.268), and shorter length of stay (3.5 vs 4.3 days, p = 0.294). Conclusions This is the first study in otolaryngology or neurosurgery to compare operative times and outcomes for AO versus TA cases at a single academic institution. Operative times were significantly decreased and a trend toward a decrease in patient morbidity was noted for cases performed solely by attendings. The valuation of teaching activities in the operating room is a necessary first step toward optimizing the allocation of resources and funding of surgical education.

Intracellular uptake and associated toxicity of silver nanoparticles in Caenorhabditis elegans.

Silver nanoparticles (AgNPs) are frequently used as antimicrobials. While the mechanism(s) by which AgNPs are toxic are unclear, their increasing use raises the concern that release into the environment could lead to environmental toxicity. We characterized the physicochemical behavior, uptake, toxicity (growth inhibition), and mechanism of toxicity of three AgNPs with different sizes and polyvinylpyrrolidone (PVP) or citrate coatings to the nematode Caenorhabditis elegans. We used wild-type (N2) C. elegans and strains expected to be sensitive to oxidative stress (nth-1, sod-2 and mev-1), genotoxins (xpa-1 and nth-1), and metals (mtl-2). Using traditional and novel analytical methods, we observed significant aggregation and extra-organismal dissolution of silver, organismal uptake and, in one case, transgenerational transfer of AgNPs. We also observed growth inhibition by all tested AgNPs at concentrations in the low mg/L levels. A metallothionein-deficient (mtl-2) strain was the only mutant tested that exhibited consistently greater AgNP sensitivity than wild-type. Although all tested AgNPs were internalized (passed cell membranes) in C. elegans, at least part of the toxicity observed was mediated by ionic silver. Finally, we describe a modified growth assay that permits differentiation between direct growth-inhibitory effects and indirect inhibition mediated by toxicity to the food source.

Blimp-1/PRDM1 mediates transcriptional suppression of the NLR gene NLRP12/Monarch-1.

NLR (nucleotide-binding domain, leucine-rich repeat) proteins are intracellular regulators of host defense and immunity. One NLR gene, NLRP12 (NLR family, pyrin domain containing 12)/Monarch-1, has emerged as an important inhibitor of inflammatory gene expression in human myeloid cells. This is supported by genetic analysis linking the loss of a functional NLRP12 protein to hereditary periodic fever. NLRP12 transcription is diminished by specific TLR stimulation and myeloid cell maturation, consistent with its role as a negative regulator of inflammation. The NLRP12 promoter contains a novel Blimp-1 (B lymphocyte-induced maturation protein-1)/PRDM1 (PR domain-containing 1, with ZNF domain) binding site, and Blimp-1 reduces NLRP12 promoter activity, expression, and histone 3 acetylation. Blimp-1 associates with the endogenous NLRP12 promoter in a TLR-inducible manner and mediates the down-regulation of NLRP12 expression by TLR agonists. As expected, the expression of NLRP12 and Blimp-1 is inversely correlated. Analysis of Blimp-1(-/-) murine myeloid cells provides physiologic evidence that Blimp-1 reduces NLRP12 gene expression during cell differentiation. This demonstrates a novel role for Blimp-1 in the regulation of an NLR gene.