Jon Mallen-St. Clair

Mast cells promote atherosclerosis by releasing proinflammatory cytokines.

Mast cells contribute importantly to allergic and innate immune responses by releasing various preformed and newly synthesized mediators. Previous studies have shown mast cell accumulation in human atherosclerotic lesions. This report establishes the direct participation of mast cells in atherogenesis in low-density lipoprotein receptor–deficient (Ldlr−/−) mice. Atheromata from compound mutant Ldlr−/− KitW-sh/W-sh mice showed decreased lesion size, lipid deposition, T-cell and macrophage numbers, cell proliferation and apoptosis, but increased collagen content and fibrous cap development. In vivo, adoptive transfer of syngeneic wild-type or tumor necrosis factor (TNF)-α-deficient mast cells restored atherogenesis to Ldlr−/−KitW-sh/W-sh mice. Notably, neither interleukin (IL)-6- nor interferon (IFN)-γ-deficient mast cells did so, indicating that the inhibition of atherogenesis in Ldlr−/−KitW-sh/W-sh mice resulted from the absence of mast cells and mast cell–derived IL-6 and IFN-γ. Compared with wild-type or TNF-α-deficient mast cells, those lacking IL-6 or IFN-γ did not induce expression of proatherogenic cysteine proteinase cathepsins from vascular cells in vitro or affect cathepsin and matrix metalloproteinase activities in atherosclerotic lesions, implying that mast cell–derived IL-6 and IFN-γ promote atherogenesis by augmenting the expression of matrix-degrading proteases. These observations establish direct participation of mast cells and mast cell–derived IL-6 and IFN-γ in mouse atherogenesis and provide new mechanistic insight into the pathogenesis of this common disease.

In liver fibrosis, dendritic cells govern hepatic inflammation in mice via TNF-α

Hepatic fibrosis occurs during most chronic liver diseases and is driven by inflammatory responses to injured tissue. Because DCs are central to modulating liver immunity, we postulated that altered DC function contributes to immunologic changes in hepatic fibrosis and affects the pathologic inflammatory milieu within the fibrotic liver. Using mouse models, we determined the contribution of DCs to altered hepatic immunity in fibrosis and investigated the role of DCs in modulating the inflammatory environment within the fibrotic liver. We found that DC depletion completely abrogated the elevated levels of many inflammatory mediators that are produced in the fibrotic liver. DCs represented approximately 25% of the fibrotic hepatic leukocytes and showed an elevated CD11b+CD8- fraction, a lower B220+ plasmacytoid fraction, and increased expression of MHC II and CD40. Moreover, after liver injury, DCs gained a marked capacity to induce hepatic stellate cells, NK cells, and T cells to mediate inflammation, proliferation, and production of potent immune responses. The proinflammatory and immunogenic effects of fibrotic DCs were contingent on their production of TNF-alpha. Therefore, modulating DC function may be an attractive approach to experimental therapeutics in fibro-inflammatory liver disease.

Mast cell dipeptidyl peptidase I mediates survival from sepsis

Sepsis is a common, life-threatening disease for which there is little treatment. The cysteine protease dipeptidyl peptidase I (DPPI) activates granule-associated serine proteases, several of which play important roles in host responses to bacterial infection. To examine DPPIs role in sepsis, we compared DPPI(-/-) and DPPI(+/+) mice using the cecal ligation and puncture (CLP) model of septic peritonitis, finding that DPPI(-/-) mice are far more likely to survive sepsis. Outcomes of CLP in mice lacking mast cell DPPI reveal that the absence of DPPI in mast cells, rather than in other cell types, is responsible for the survival advantage. Among several cytokines surveyed in peritoneal fluid and serum, IL-6 is highly and differentially expressed in DPPI(-/-) mice compared with DPPI(+/+) mice. Remarkably, deleting IL-6 expression in DPPI(-/-) mice eliminates the survival advantage. The increase in IL-6 in septic DPPI(-/-) mice, which appears to protect these mice from death, may be related to reduced DPPI-mediated activation of mast cell tryptase and other peptidases, which we show cleave IL-6 in vitro. These results indicate that mast cell DPPI harms the septic host and that DPPI is a novel potential therapeutic target for treatment of sepsis.

Structure and activity of human pancreasin, a novel tryptic serine peptidase expressed primarily by the pancreas

In a search for genes encoding the serine peptidases prostasin and testisin, which are expressed mainly in prostate and testis, respectively, we identified a related, novel gene. Sequencing of cDNA allowed us to deduce the full amino acid sequence of the human gene product, which we term “pancreasin” because it is transcribed strongly in the pancreas. The idiosyncratic 6-exon organization of the gene is shared by a small group of tryptic proteases, including prostasin, testisin, and γ-tryptase. Like the other genes, the pancreasin gene resides on chromosome 16p. Pancreasin cDNA predicts a 290-residue, N-glycosylated, serine peptidase with a typical signal peptide, a 12-residue activation peptide cleaved by tryptic hydrolysis, and a 256-amino acid catalytic domain. Unlike prostasin and other close relatives, human pancreasin and a nearly identical chimpanzee homologue lack a carboxyl-terminal membrane anchor, although this is present in 328-residue mouse pancreasin, the cDNA of which we also cloned and sequenced. In marked contrast to prostasin, which is 43% identical in the catalytic domain, human pancreasin is transcribed strongly in pancreas (and in the pancreatic ductal adenocarcinoma line, HPAC) but weakly or not at all in kidney and prostate. Antibodies raised against pancreasin detect cytoplasmic expression in HPAC cells. Recombinant, epitope-tagged pancreasin expressed in Chinese hamster ovary cells is glycosylated and secreted as an active tryptic peptidase. Pancreasins preferences for hydrolysis of extended peptide substrates feature a strong preference for P1 Arg and differ from those of trypsin. Pancreasin is inhibited by benzamidine and leupeptin but resists several classic inhibitors of trypsin. Thus, pancreasin is a secreted, tryptic serine protease of the pancreas with novel physical and enzymatic properties. These studies provide a rationale for exploring the natural targets and roles of this enzyme.

Epidemiology and Treatment of Lacrimal Gland Tumors: A Population-Based Cohort Analysis

IMPORTANCE Primary tumors of the lacrimal gland are rare and are associated with substantial morbidity and mortality. The literature regarding these tumors is limited to case series and case reports. OBJECTIVE To examine the incidence, treatment, and overall survival (OS) and disease-specific survival (DSS) of patients with cancer of the lacrimal gland. DESIGN, SETTING, AND PARTICIPANTS Population-based cohort analysis using the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with primary tumors of the lacrimal gland from 1973 to 2010. MAIN OUTCOMES AND MEASURES Overall survival and DSS. RESULTS A total of 321 patients with nonlymphoid tumors of the lacrimal gland were identified. The most common histological subtypes were adenoid cystic carcinoma (ACC) (32.1%) and squamous cell carcinoma (SCC) (29.9%). Survival analysis revealed a 5-year OS and DSS for all lacrimal gland tumors of 60% and 75%, respectively. On univariate analysis, low tumor grade (P = .04) and surgical treatment (P < .001) were associated with significantly better OS. For ACC tumors, surgery (P = .009), but not radiotherapy (P = .44), was found to significantly improve OS. For SCC tumors, surgical treatment significantly improved both OS (P < .001) and DSS (P = .004); radiation therapy also significantly improved OS (P = .03). Using a multivariable analysis model, age (hazard ratio [HR], 1.03 [95% CI, 1.01-1.04]; P < .001), surgery (HR, 0.43 [95% CI, 0.25-0.75]; P = .003), and T stage at presentation (HR, 1.18 [95% CI, 1.01-1.37]; P = .03) were found to be independent predictors of OS. For ACC alone, age (HR, 1.04 [95% CI, 1.02-1.06]; P < .001) and surgery (HR, 0.35 [95% CI, 0.13-0.91]; P = .03) were independent predictors of OS. For SCC, age (HR, 1.05 [95% CI, 1.02-1.09]; P = .005), surgical resection (HR, 0.31 [95% CI, 0.12-0.83]; P = .02), and radiation therapy (HR, 0.33 [95% CI, 0.14-0.80]; P = .01) were independent predictors of OS. CONCLUSIONS AND RELEVANCE Our study demonstrates that ACC is the most common malignant epithelial neoplasm of the lacrimal gland. Determinants of survival for tumors of the lacrimal gland include age at diagnosis and surgical therapy. Radiation therapy is associated with improved DSS in SCC but not in ACC.

Human papillomavirus in oropharyngeal cancer: The changing face of a disease.

The last decade has brought about an unexpected rise in oropharyngeal squamous cell carcinoma (OPSCC) primarily in white males from the ages of 40-55years, with limited exposure to alcohol and tobacco. This subset of squamous cell carcinoma (SCC) has been found to be associated with human papillomavirus infection (HPV). Other Head and Neck Squamous Cell carcinoma (HNSCC) subtypes include oral cavity, hypopharyngeal, nasopharyngeal, and laryngeal SCC which tend to be HPV negative. HPV associated oropharyngeal cancer has proven to differ from alcohol and tobacco associated oropharyngeal carcinoma in regards to the molecular pathophysiology, presentation, epidemiology, prognosis, and improved response to chemoradiation therapy. Given the improved survival of patients with HPV associated SCC, efforts to de-intensify treatment to decrease treatment related morbidity are at the forefront of clinical research. This review will focus on the important differences between HPV and tobacco related oropharyngeal cancer. We will review the molecular pathogenesis of HPV related oropharyngeal cancer with an emphasis on new paradigms for screening and treating this disease.

Cathepsins L and S are not required for activation of dipeptidyl peptidase I (cathepsin C) in mice

Abstract The cysteine protease dipeptidyl peptidase I (DPPI) activates granule-associated immune-cell serine proteases. The in vivo activator of DPPI itself is unknown; however, cathepsins L and S are candidates because they activate pro-DPPI in vitro. In this study, we tested whether cathepsins L and S activate pro-DPPI in vivo by characterizing DPPI activity and processing in cells lacking cathepsins L and S. DPPI activity, and the relative size and amounts of DPPI heavy and light chains, were identical in mast cells from wild-type and cathepsin L/S double-null mice. Furthermore, the activity of DPPI-dependent chymase was preserved in tissues of cathepsin L/S double-null mice. These results show that neither cathepsin L nor S is required for activation of DPPI and suggest that one or more additional proteases is responsible.

Significance of Tumor Stage in Sinonasal Undifferentiated Carcinoma Survival A Population-Based Analysis

Objective To describe the incidence and determinants of survival of patients with sinonasal undifferentiated carcinoma (SNUC) from 1973 to 2011 using the SEER database (Surveillance, Epidemiology, and End Results), with consideration of tumor stage based on the Kadish system. Study Design Retrospective database analysis. Setting Academic medical center. Subjects and Methods The SEER registry was utilized to calculate survival trends for 328 patients with SNUC between 1973 and 2011. Patient data were then analyzed with respect to histopathology, age, sex, race, subsite, modified Kadish stage, tumor size, and treatments rendered. Results The cohort was composed of 61.9% males with median age of 60 years. The median overall survival (OS) was 1.9 years. Most tumors presented in the nasal cavity, maxillary sinus, and ethmoid sinus (29.3%, 27.4%, 21%, respectively); 43.7% of patients received both surgical and radiation therapy. OS at 2, 5, and 10 years was 43%, 30%, and 25%, respectively. On univariate analysis, age, Kadish stage, and tumor size were associated with worse OS and disease-specific survival (DSS), while surgery and radiation therapy were associated with improved OS and DSS (all P < .05). On multivariate analysis, radiation therapy and lower Kadish stage were associated with improved OS and DSS, while younger age was additionally associated with improved OS (all P < .05). Conclusion SNUC is a rare but aggressive sinonasal malignancy. Tumor stage as determined by the Kadish system is associated with worse survival, with radiation therapy appearing to play a key role in therapeutic management.

Epidemiology of Squamous Cell Carcinoma of the Lip in the United States: A Population-Based Cohort Analysis.

Importance Squamous cell carcinoma of the lip (lip SCC) composes more than 25% of all oral cancers. Most of the demographic and prognostic indicators for lip SCC are only available through retrospective case series. Objective To examine the incidence, treatment, overall survival, and disease-specific survival (DSS) of patients with lip SCC. Design, Setting, and Participants Population-based cohort analysis using the Surveillance, Epidemiology, and End Results database identified patients with lip SCC between January 1, 1973, and December 31, 2012. Main Outcomes and Measures Overall survival and DSS. Results A total of 15 832 cases of lip SCC were identified. The cohort was composed of 12 945 men (81.8%) and 2887 women (18.2%). The mean age at diagnosis was 66.1 years. White patients accounted for 98.4% of the cases. Most of the tumors presented in the lower lip (77.8% external and 10.2% mucosal), whereas the external upper lip, mucosal upper lip, and the oral commissure represented 8%, 1%, and 1.2% of all cases, respectively. Of the patients, 91.2% underwent surgical therapy, 7.7% received radiation therapy, and 4.7% received both. Overall survival at 2 years, 5 years, and 10 years was 85.5%, 69.9%, and 50.2%, respectively. Multivariate analysis revealed that age, primary site, T stage, and N stage were determinants of overall survival and DSS. Kaplan-Meier survival analysis showed that SCC of the upper and lower lip had similar overall survival (163.6 months vs 163.8 months) and DSS (418.6 months vs 423.6 months). In contrast, SCC of the oral commissure had significantly lower overall survival (128.5 months) and DSS (286.7 months). Conclusions and Relevance Our study demonstrates that lip SCC predominantly affects white men in their mid-60s. The determinants of survival for lip SCC include age at diagnosis, primary site, T stage, and N stage. Squamous cell carcinoma of the upper lip and lower lip had similar survival, whereas SCC of the oral commissure was associated with decreased survival.

p38 MAPK mediates epithelial-mesenchymal transition by regulating p38IP and Snail in head and neck squamous cell carcinoma.

BACKGROUND In the present study, we investigated the role of p38-p38IP signaling in the inflammation-induced promotion of epithelial-to-mesenchymal transition (EMT) in Head and Neck Squamous Cell Carcinoma (HNSCC). METHODS Quantitative RT-PCR, western blot analysis, spheroid modeling and immunohistochemical staining of human HNSCC tissue sections were used. RESULTS p38 inhibitor treated and p38 shRNA HNSCC cell lines demonstrate a significant upregulation in E-cadherin mRNA and a decrease in the mRNA expression of Snail. p38 binds to and stabilizes p38IP, a subunit of histone SPT3-TAF9-GCN5 acetyltransferase (STAGA), resulting in enhanced transcription of Snail. p38 shRNA HNSCC cell lines show a less invasive phenotype in a spheroid model. In clinical HNSCC samples, p38 interacting protein (p38IP) is significantly increased compared to adjacent normal tissue. An inverse relationship between p38, p38IP and E-cadherin is demonstrated. CONCLUSIONS Herein we provide the first report that p38-p38IP is required for the Snail-induced E-cadherin down-regulation and cell invasion in HNSCC.