Adjuvant use of antibiotics with corticosteroids in inflammatory bowel disease exacerbations requiring hospitalisation: a retrospective cohort study and meta-analysis.

BACKGROUND: Patients hospitalised with an exacerbation of inflammatory bowel disease (IBD) often receive antibiotics in addition to intravenous steroids. However, their efficacy in this setting is unclear. AIM: To ascertain if the addition of antibiotics to intravenous steroids modifies short and long-term clinical outcomes. METHODS: Our study included IBD patients hospitalised between 2009 and 2014 who received intravenous (IV) steroids with or without adjuvant antibiotics. Outcomes of interest included length of stay (LOS), need for medical and surgical rescue therapy during the hospitalisation, and at 90 and 365 days. A meta-analysis of previously published randomised trials was additionally performed. RESULTS: A total of 354 patients were included [145 ulcerative colitis (UC); 209 Crohn's disease (CD)]. In CD, combination of IV steroids and antibiotics did not change need for in-hospital medical rescue therapy, surgery or hospitalisations at 1 year but was associated with greater LOS (6.1 vs. 4.6 days, P = 0.02). In UC, patients receiving antibiotics were less likely to require in-hospital medical rescue therapy [odds ratio (OR): 0.42, 95% confidence interval (CI): 0.19-0.93] but experienced no statistically significant differences in LOS, in-hospital surgery, re-hospitalisations or surgery by 1 year. A meta-analysis of three relevant randomised trials demonstrated no difference in clinical improvement with antibiotics over placebo (OR: 1.08, 95% CI: 0.50-2.32). CONCLUSIONS: The addition of antibiotics to intravenous steroids for treatment of IBD exacerbations was associated with a reduced need for in-hospital medical rescue therapy in ulcerative colitis without significant long-term benefit, and did not affect short- or long-term outcomes in Crohn's disease.

New onset idiosyncratic liver enzyme elevations with biological therapy in inflammatory bowel disease.

BACKGROUND: Anti-tumour necrosis factor α (anti-TNF) agents have been implicated in drug-induced liver injury. There is minimal data on this occurrence in inflammatory bowel disease (IBD) patients. AIM: To identify the characteristics of liver enzyme elevations following anti-TNF therapy initiation in IBD. METHODS: A retrospective cohort of patients initiating anti-TNF therapy were analysed for new onset alanine transaminase (ALT) elevation (≥60 U/L). We collected data on natural history, outcomes and patient characteristics compared with controls with persistent normal liver enzymes. Likelihood of causal association was assessed using the RUCAM score. RESULTS: From 1753 patients initiating an anti-TNF (1170 infliximab, 575 adalimumab, 8 certolizumab), 102 (6%) developed new onset ALT elevation. In 54 (53%), this could be linked to an alternate aetiology. Among those with idiopathic ALT elevations, the median time to ALT elevation from anti-TNF initiation was 18 weeks and median peak ALT was 96 U/L. Six underwent liver biopsy, all demonstrating hepatitis with autoimmune features. Compared to controls, cases were on a lower dose of infliximab (5.7 vs. 6.7 mg/kg, P = 0.02) but were otherwise similar in body mass index, sex and age. On follow-up, 34 continued the anti-TNF, 14 stopped therapy and 4 initiated steroids. Most (85%) normalised their LFTs after a median of 17 weeks including 28 (82%) of those who continued anti-TNF therapy. Ten patients were transitioned to a second anti-TNF without recurrence. CONCLUSIONS: ALT elevations occurred in 6% of IBD patients initiating anti-TNF therapy. Most idiopathic elevations were mild, transient and resolved despite therapy continuation.

Accuracy and interrater reliability for the diagnosis of Barrett's neoplasia among users of a novel, portable high-resolution microendoscope.

The high-resolution microendoscope (HRME) is a novel imaging modality that may be useful in the surveillance of Barrett's esophagus in low-resource or community-based settings. In order to assess accuracy and interrater reliability of microendoscopists in identifying Barrett's-associated neoplasia using HRME images, we recruited 20 gastroenterologists with no microendoscopic experience and three expert microendoscopists in a large academic hospital in New York City to interpret HRME images. They prospectively reviewed 40 HRME images from 28 consecutive patients undergoing surveillance for metaplasia and low-grade dysplasia and/or evaluation for high-grade dysplasia or cancer. Images were reviewed in a blinded fashion, after a 4-minute training with 11 representative images. All imaged sites were biopsied and interpreted by an expert pathologist. Sensitivity of all endoscopists for identification of high-grade dysplasia or cancer was 0.90 (95% confidence interval [CI]: 0.88-0.92) and specificity was 0.82 (95% CI: 0.79-0.85). Positive and negative predictive values were 0.72 (95% CI: 0.68-0.77) and 0.94 (95% CI: 0.92-0.96), respectively. No significant differences in accuracy were observed between experts and novices (0.90 vs. 0.84). The kappa statistic for all raters was 0.56 (95% CI: 0.54-0.58), and the difference between groups was not significant (0.64 vs. 0.55). These data suggest that gastroenterologists can diagnose Barrett's-related neoplasia on HRME images with high sensitivity and specificity, without the aid of prior microendoscopy experience.

Genetic risk factors for Clostridium difficile infection in ulcerative colitis.

BACKGROUND: Patients with inflammatory bowel disease (IBD) are at higher risk for Clostridium difficile infection (CDI). Disruption of gut microbiome and interaction with the intestinal immune system are essential mechanisms for pathogenesis of both CDI and IBD. Whether genetic polymorphisms associated with susceptibility to IBD are also associated with risk of CDI is unknown. AIMS: To use a well-characterised and genotyped cohort of patients with UC to (i) identify clinical risk factors for CDI; (ii) examine if any of the IBD genetic risk loci were associated with CDI; and (iii) to compare the performance of predictive models using clinical and genetic risk factors in determining risk of CDI. METHODS: We used a prospective registry of patients from a tertiary referral hospital. Medical record review was performed to identify all ulcerative colitis (UC) patients within the registry with a history of CDI. All patients were genotyped on the Immunochip. We examined the association between the 163 risk loci for IBD and risk of CDI using a dominant genetic model. Model performance was examined using receiver operating characteristics curves. RESULTS: The study included 319 patients of whom 29 developed CDI (9%). Female gender and pancolitis were associated with increased risk, while use of anti-TNF was protective against CDI. Six genetic polymorphisms including those at TNFRSF14 [Odds ratio (OR) 6.0, P-value 0.01] were associated with increased risk while 2 loci were inversely associated. On multivariate analysis, none of the clinical parameters retained significance after adjusting for genetics. Presence of at least one high-risk locus was associated with an increase in risk for CDI (20% vs. 1%) (P = 6 × 10⁻9). Compared to 11% for a clinical model, the genetic loci explained 28% of the variance in CDI risk and had a greater AUROC. CONCLUSION: Host genetics may influence susceptibility to Clostridium difficile infection in patients with ulcerative colitis.

Long-term outcome of a third anti-TNF monoclonal antibody after the failure of two prior anti-TNFs in inflammatory bowel disease.

BACKGROUND: A significant proportion of patients with IBD lose response to anti-TNF therapies. There is limited knowledge of the long-term outcomes of those who have failed two anti-TNF agents and commenced a third. AIM: To examine the safety and efficacy of third anti-TNF treatment after failure of two prior anti-TNF agents in patients with inflammatory bowel disease. METHODS: This was a retrospective study of all IBD patients [Crohn's disease (CD), ulcerative colitis (UC)] treated with a third anti-TNF agent after loss of response or intolerance to two prior anti-TNF agents at a single tertiary North American centre. Disease activity, drug therapy and Montreal phenotypes were noted at disease onset and commencement of the third anti-TNF agent. Kaplan-Meier estimates were used to calculate the probability of remaining on the third anti-TNF agent and to identify predictors of long-term clinical response. RESULTS: A total of 63 patients (64% women, 57 CD and 6 UC) were included in the analysis. The mean disease duration at initiation of third anti-TNF was 12 years. Thirty-five (55.6%) patients discontinued the third anti-TNF after a mean of 13.2 months. Probability of remaining on the third anti-TNF was 0.69, 0.55, 0.37 and 0.25 at 6, 12, 24 and 36 months respectively. Prior primary nonresponders to the first anti-TNF agent [hazard ratio (HR) 6.4, 95% CI 2.5-16.1] and persistent disease activity at 3 months after commencement of a third anti-TNF (HR 3.2, 95% CI 1.3-7.8) predicted poorer response. CONCLUSIONS: Over half of patients with inflammatory bowel disease, initiated on a third anti-TNF agent after failure of two prior anti-TNF drugs, are able to remain on the third anti-TNF at 1 year.

Inverse association between hepatic stellate cell apoptosis and fibrosis in chronic hepatitis C virus infection.

Perisinusoidal hepatic stellate cells (HSC) are the principal fibrogenic cells in the liver. In animal models, HSC apoptosis is the predominant clearance mechanism of activated HSC, although data evaluating whether the same processes occur in humans are limited. We conducted a cross-sectional study to evaluate the association between HSC apoptosis and fibrosis stage in subjects with chronic hepatitis C virus (HCV) infection (n = 44) and HCV-negative controls with normal liver histology (n = 9). We used immunohistochemical techniques to identify activated (alpha-smooth muscle actin+), proliferative (Ki-67+) and apoptotic (terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end-labelling+) HSC in liver biopsy specimens from all subjects. The same pathologist enumerated positive cells per high-power field (HPF, x 200) in 20 periportal/lobular areas. HSC apoptosis was decreased in HCV-positive subjects compared with controls (median 0.4, range 0.0-3.1 vs 1.1, 0.2-3.5 cells/HPF, P = 0.02). Among HCV-positive subjects, HSC apoptosis was decreased in those with moderate to advanced fibrosis (P = 0.04) compared with those with mild fibrosis. By multivariate analysis, HSC apoptosis decreased by an average of 0.14 cells/HPF (95% confidence interval 0.01-0.28 cells/HPF) per increase in fibrosis stage (P = 0.04). While the number of activated and proliferative HSC was significantly increased in HCV-infected subjects compared with that in uninfected controls, the numbers of these cells did not differ between HCV-infected subjects with mild vs moderate/advanced fibrosis. In conclusion, the number of apoptotic HSC was significantly decreased in HCV-infected subjects with advanced fibrosis. In chronic HCV infection, inhibition of HSC apoptosis may be one mechanism by which fibrosis progresses.

Expression and alterations of the PTEN / AKT / mTOR pathway in ameloblastomas.

OBJECTIVES: Recently, an allelic loss of phosphatase and tensin homologue (PTEN) was shown to occur in ameloblastomas. In carcinogenesis, loss of PTEN allows for overactivity of the phosphatidylinositol-3-kinase/protein kinase B (PI3K / AKT) pathway inducing an upregulation of mammalian-target of rapamycin (mTOR) and its downstream effector ribosomal-subunit-6 kinase (S6K); allowing for uncontrolled cell proliferation, apoptosis inhibition and cell cycle deregulation. METHODS: Thirty ameloblastomas and five dental follicles were studied, looking at the immunohistochemical expression of total PTEN and AKT, as well as their phosphorylated (p) active forms, and the downstream effector and indicator of mTOR activity p70 ribosomal-subunit-6 kinase (pS6K). Also assessed was the expression of extracellular-signal-regulated kinase (ERK), which cross talks with AKT. RESULTS: Total PTEN was absent in 33.3% of ameloblastomas, while its stabilized, phosphorylated(ser380 / thr382 / thr383) form was absent in 83.3% of tumors. In contrast, AKT was expressed in 83.3% of ameloblastomas, showing high expression of the p-thr(308)AKT and p-ser(473) AKT forms in 93.3% and 56.6% of cases, respectively. Further, the mTOR activated pS6K(ser240 / 244) was detected in 86.7% of ameloblastomas, while ERK was overexpressed in 70.0% of the cases. CONCLUSION: Immunohistochemical analysis of aberrant signaling in the PI3K/AKT/mTOR pathway in ameloblastomas may represent a valuable tool for elucidating pathogenesis, aggressiveness and selecting optimal therapeutics.

Survivin is a downstream target and effector of sulindac-sensitive oncogenic Stat3 signalling in head and neck cancer.

Sulindac exerts its antitumorigenic effects in oral squamous cell carcinoma (SCC) cells by modulating survivin in a Stat3-dependent manner. Immunohistochemistry was used to detect the protein levels of phosphorylated-tyrosine Stat3 (p-tyr Stat3) and survivin in SCC tissues. Western blot, reverse transcriptase polymerase chain reaction, Annexin-V and cell proliferation assays were used to determine p-tyr Stat3 and survivin protein and mRNA expression, and cell viability following treatment with cyclooxygenase (COX) inhibitors, Stat3 siRNA, or the forced expression of Stat3 or survivin. Immunohistochemical analysis revealed an overexpression of p-tyr Stat3 in T1 SCCs. The importance of constitutive Stat3 activation in tumourigenesis was confirmed by siRNA inhibition of Stat3, resulting in cell growth inhibition and apoptosis, via a downregulation of survivin mRNA and protein expression. The forced expression of survivin partially reversed these effects of Stat3 inhibition. Sulindac, but not other COX inhibitors, downregulated Stat3, which correlated to an inhibition of cell proliferation, survival and survivin expression. Transfection of constitutively active Stat3 restored survivin expression and partially rescued SCC cells from sulindac-induced antitumorigenic effects. These data indicate that survivin is a downstream target and effector of oncogenic Stat3 signalling in SCC, which is targeted by sulindac in a COX-2-independent manner.

Targeting the STAT pathway in head and neck cancer: recent advances and future prospects.

Head and neck cancer, the sixth most common type of cancer worldwide, is associated with a dismal prognosis that has minimally improved during the last few decades. Future advances in the treatment and prognosis of this fatal disease largely rely upon a better understanding of the molecular events that underlie tumor development and progression, allowing specific targeting of the involved molecules and pathways. In this context, recent efforts have revolved around a family of transcription factors known as STATs (signal transducers and activators of transcription). STAT proteins comprise a family of latent cytoplasmic transcription factors that become transiently activated in response to extracellular signals, leading to regulation of diverse physiological responses. There is compelling evidence that persistent activation of specific STAT molecules, especially Stat3 and Stat5, possesses oncogenic properties in a number of human cancers, including head and neck cancer. The presence of constitutively activated STAT molecules in cancer cells is mainly attributed to the dysregulation of upstream activating pathways and the aberration of negative regulatory mechanisms. The end result is induction of specific target genes that stimulate cell proliferation, prevent apoptosis, promote angiogenesis and facilitate tumor immune evasion. Therefore, targeting and disruption of oncogenic STAT signaling may theoretically be accomplished through various approaches, involving direct (e.g. interference with the various facets of STAT expression, activation or function) and indirect strategies (e.g. inhibition of upstream signaling events and enhancement or restoration of negative regulatory mechanisms). The availability of multiple potential targets for interruption of aberrant STAT signaling in cancer and the thus-far promising results have generated optimism for the clinical applicability of STAT targeting in head and neck cancer, which is the focus of this review.

Signal transducers and activators of transcription: insights into the molecular basis of oral cancer.

Recent efforts on developing more direct and effective targets for cancer therapy have revolved around a family of transcription factors known as STATs (signal transducers and activators of transcription). STAT proteins are latent cytoplasmic transcription factors that become activated in response to extracellular signaling proteins. STAT proteins have been convincingly reported to possess oncogenic properties in a plethora of human cancers, including oral and oropharyngeal cancer. Signal transduction pathways mediated by these oncogenic transcription factors and their regulation in oral cancer are the focus of this review.

Abrogation of IL-6-mediated JAK signalling by the cyclopentenone prostaglandin 15d-PGJ(2) in oral squamous carcinoma cells.

Cyclopentenone 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) exerts antineoplastic effects on various types of human cancer. We recently showed that treatment with 15d-PGJ(2) induces apoptosis accompanied by downregulation of the oncogenic signal transducer and activator of transcription 3 (Stat3) signalling in human oral squamous cell carcinoma (SCC) cells. The current study examines the effects of 15d-PGJ(2) on the epidermal growth factor receptor (EGFR) and Janus Kinase (JAK)-mediated signalling pathways. Inhibition of Stat3 by 15d-PGJ(2) was abolished by exogenous stimulation with transforming growth factor alpha (TGF-alpha), but not interleukin 6 (IL-6), supporting a selective effect of 15d-PGJ(2) on IL-6-mediated signalling. Importantly, 15d-PGJ(2) selectively abrogated constitutive and IL-6-mediated JAK phosphorylation without affecting EGFR-activated levels. Moreover, the inhibitory effect of 15d-PGJ(2) on JAK signalling required the reactive alpha,beta-unsaturated carbon within the cyclopentenone ring. Targeting of JAK signalling using a specific JAK inhibitor also abolished Stat3 phosphorylation and resulted in apoptosis in oral SCC cells. Our findings provide the first evidence for 15d-PGJ(2)-mediated downregulation of constitutive and IL-6-induced JAK signalling in cancer and support that JAK inhibition and suppression of EGFR-independent Stat3 activation by 15d-PGJ(2) represent a promising approach for induction of apoptosis in oral SCC cells.

Cyclosporin A induces proliferation in human gingival fibroblasts via induction of transforming growth factor-beta1.

BACKGROUND: Cyclosporin A (CsA) is a widely used immunosuppressant that causes significant side effects including gingival overgrowth. The pathogenesis of this condition is not fully understood; however, recent studies show that CsA regulates the transcription of several cytokines including transforming growth factor-beta 1 (TGF-beta1). In this study, we evaluated the effects of CsA and TGF-beta1 on human normal gingival (NG) fibroblast proliferation, and explored a possible autocrine stimulation of TGF-beta1 as a cellular regulator of proliferation induced by CsA in NG fibroblasts. METHODS: NG fibroblast cell lines were incubated with increasing concentrations of CsA or TGF-beta1 and the proliferation index determined by automatic cell counting, BrdU incorporation, PCNA expression, and mitotic potential. To determine the effect of TGF-beta1 on the proliferation rate of NG fibroblasts under CsA treatment, NG fibroblast cultures were simultaneously treated with CsA and antisense oligonucleotides against the translation-start site of the TGF-beta1 mRNA. RESULTS: Treatment of NG fibroblasts with CsA or TGF-beta1 significantly stimulated the cell proliferation in a dose-dependent manner. Furthermore, neutralization of TGF-beta1 production in CsA-treated NG fibroblasts inhibited CsA's effect on NG fibroblast proliferation, demonstrating an autocrine stimulatory effect of TGF-beta1 in CsA-treated NG fibroblast proliferation. CONCLUSION: The results presented here suggest that CsA stimulatory induction of NG fibroblast proliferation is mediated via TGF-beta1 in an autocrine fashion.

Phenotypic switching of VEGF and collagen XVIII during hypoxia in head and neck squamous carcinoma cells.

The present study sought to determine the potential role of stress activated MAPK and phosphatidylinositol 3-kinase (PI3K) signaling pathways in mediating phenotypic switching between angiogenic and angiostatic elements among squamous cell carcinoma (SCC) cell lines. In particular, we investigated the effects of hypoxia and those of cobalt chloride (CoCl(2)), which mimics the hypoxic response including the production of reactive oxygen species, on such phenotypic shifts. The expression and production of collagen XVIII, and CBP2/Hsp47 provided a measure of an angiostatic phenotype, while vascular endothelial growth factor (VEGF) expression was used to assess potential angiogenic states. These studies revealed that hypoxia produced a slight up-regulation of collagen XVIII and CBP2/Hsp47 that was inhibited by the stress kinase inhibitor SB203580 but was unaffected by N-acetylcysteine (NAC). In addition, VEGF expression was increased following hypoxia and this effect was reversed with inhibition of by SB203580. Conversely, CoCl(2) significantly diminished the expression of both collagen XVIII and CBP2/Hsp47 and enhanced VEGF expression. These changes were reversed by the PI3K inhibitor wortmannin and by treating cells with NAC. These studies show that phenotypic switching between collagen XVIII and VEGF is controlled by stress activated kinases under hypoxia, and PI3K signaling pathways as well as reactive oxygen species (ROS) following CoCl(2) treatment. Furthermore, modulation of the angiogenic switch is most profound during Akt activation than during activation of stress activated kinases.

Expression of Sec61 alpha in F9 and P19 teratocarcinoma cells after retinoic acid treatment.

Nascent procollagen peptides and other secretory proteins are transported across the endoplasmic reticulum (RE) membrane through a protein-conducting channel called the translocon. Sec61 alpha, a multispanning membrane translocon protein, has been implicated as essential for translocation of polypeptides chains into the cisterns of the ER. However, it is not known whether Sec61 alpha is ubiquitously expressed in collagen producing teratocarcinoma cells. Furthermore, the production, expression, and utilization of Sec61 alpha may depend on the cell differentiation stage. Stem cells from many cultured teratocarcinoma cell lines such as F9 and P19 cells are capable of differentiation in response to low retinoic acid concentrations. This differentiation of the tumorigenic stem cells results in tumorigenicity loss. For this study, mouse F9 and P19 teratocarcinoma cells were grown in culture medium treated with or without retinoic acid. Expression of Sec61 alpha was determined by reverse trancriptase polimerase chain reaction (RT-PCR). In untreated conditions, F9 cells expressed undetected Sec61 alpha amounts. It was also demonstrated that Sec61 alpha expression is stimulated in F9 cells after retinoic acid treatment for 72 hours. No changes were found in Sec61 alpha expression in P19 cells after retinoic acid treatment. These data indicate that the expression of Sec61 alpha is enhanced with retinoic acid induced differentiation of F9 teratocarcinoma cells.

Targeting of human squamous carcinomas by SPA470-doxorubicin immunoconjugates.

In a quest to identify a favorable target for head and neck cancers and squamous cell carcinoma, we sought to determine if Hsp47/CBP2 could be used as a target and whether the expression of this target was influenced by hypoxia. Moreover, we determined if doxorubicin (DOX) immunoconjugates directed against Hsp47/CBP2 that linked monoclonal antibodies (MAbs) to the 13-keto position of the drug possessed high cytotoxic drug activity and antibody-directed killing of antigen bearing tumor target cells. Experiments were performed using established cell lines of human oral squamous carcinoma cells (SCCs) (SCC-4, -9, -15 and -25) obtained from American Type Culture Collection (ATCC) (Manassas, VA). In addition, the UMB2 cell line is a spontaneous mutant of SCC-9 that does not express Hsp47/CBP2 was also used. Synthesis of the immunoconjugates was accomplished by thiolating the MAbs with 2 IT and reacting the MAbs with the DOX-hydrazone. The binding of MAb-DOX conjugates to SCC cells was determined by indirect immunofluorescence and analyzed using a Becton Dickinson FACS scan with Cell Quest software. Comparison of the cytotoxicity of DOX, MAb-DOX conjugates and MAb+DOX were determined using a limited dilution assay and colony survival assays during normoxia and hypoxia. These studies revealed that SCC cells treated with the SPA470-DOX conjugate for 2 h retained the original binding activity for targeted SCC cells and was significantly more potent that unconjugated DOX, DOX-hydrazone or equivalent MAb protein+DOX. Also, SPA47-DOX produced equal to and at lower concentrations greater cell killing than equivalent dose of free DOX. During hypoxia cells treated with SPA470-DOX demonstrated a small increase in colony survival and a diminishment in cytotoxicity. SPA470-DOX conjugates target SCC cells that express Hsp47/CBP2. The demonstration that SPA470-DOX is effective during hypoxia or conditions that mimic hypoxia presumes the further utility of SPA470-DOX in treating head and neck cancers.

Histomorphometric characteristics and expression of epidermal growth factor and its receptor by epithelial cells of normal gingiva and hereditary gingival fibromatosis.

OBJECTIVE: The objective of this study was to examine the histomorphometric features and evaluate the expression of epidermal growth factor (EGF) and transmembranic receptor (EGFr) and the proliferative potential of epithelial cells from normal and hereditary gingival fibromatosis (HGF) gingival tissues. BACKGROUND: EGF is a multifunctional cytokine with a variety of biological effects including stimulation of cell proliferation by binding to its specific EGFr. METHODS: Immunohistochemistry was performed to measure EGF and EGFr expression and the epithelial cell proliferation was determined by measuring proliferating cell nuclear antigen (PCNA). RESULTS: Histomorphometric evaluation indicated that in HGF the mean height of the epithelial papillae was higher compared to the normal gingiva (NG), whereas mean epithelial area and number of epithelial papillae were quite similar in both groups. The EGF and EGFr positive cells were observed in the basal, spinous and granular cell layers of both normal and HGF tissues, with a gradual reduction from the basal layer. Although the expressions of EGF and EGFr in the control group were significantly higher than those from HGF, in HGF the epithelial papilla tips showed increased number of proliferating cells and elevated expression of EGF and EGFr. There was a correlation between the proliferative potential of epithelial cells and the expression of EGF or EGFr only in the epithelial papilla tips of HGF gingiva. CONCLUSION: Our data suggest that EGF and EGFr in the oral epithelium of HGF gingiva may stimulate epithelial cell proliferation, with the resultant apical migration of the oral epithelium and formation of the slender deep epithelial papillae; however, without hyperplastic alterations.

Expression of Sec61alpha in F9 and P19 teratocarcinoma cells after retinoic acid treatment

Nascent procollagen peptides and other secretory proteins are transported across the endoplasmic reticulum (RE) membrane through a protein-conducting channel called the translocon. Sec61alpha, a multispanning membrane translocon protein, has been implicated as essential for translocation of polypeptides chains into the cisterns of the ER. However, it is not known whether Sec61alpha is ubiquitously expressed in collagen producing teratocarcinoma cells. Furthermore, the production, expression, and utilization of Sec61alpha may depend on the cell differentiation stage. Stem cells from many cultured teratocarcinoma cell lines such as F9 and P19 cells are capable of differentiation in response to low retinoic acid concentrations. This differentiation of the tumorigenic stem cells results in tumorigenicity loss. For this study, mouse F9 and P19 teratocarcinoma cells were grown in culture medium treated with or without retinoic acid. Expression of Sec61alpha was determined by reverse trancriptase polimerase chain reaction (RT-PCR). In untreated conditions, F9 cells expressed undetected Sec61alpha amounts. It was also demonstrated that Sec61alpha expression is stimulated in F9 cells after retinoic acid treatment for 72 hours. No changes were found in Sec61alpha expression in P19 cells after retinoic acid treatment. These data indicate that the expression of Sec61alpha is enhanced with retinoic acid induced differentiation of F9 teratocarcinoma cells

Effect of transforming growth factor-beta1, interleukin-6, and interferon-gamma on the expression of type I collagen, heat shock protein 47, matrix metalloproteinase (MMP)-1 and MMP-2 by fibroblasts from normal gingiva and hereditary gingival fibromatosis.

BACKGROUND: Increased collagen and extracellular matrix deposition within the gingiva is the main characteristic feature of hereditary gingival fibromatosis (HGF). To date, it is not well established if these events are a consequence of alterations in the collagen and other extracellular matrix molecules synthesis or disturbances in the homeostatic equilibrium between synthesis and degradation of extracellular matrix molecules. Cytokines are important regulators of expression of the profibrogenic genes, including type I collagen and its molecular chaperone heat shock protein (Hsp)47 and proteolytic enzymes degrading extracellular matrix such as matrix metalloproteinases-1 and -2 (MMP-1 and MMP-2). METHODS: In this study, we analyzed the expression and production of type I collagen, Hsp47, MMP-1, and MMP-2 in normal gingiva (NG) and HGF fibroblasts, and investigated the effects of transforming growth factor-beta1 (TGF-beta1), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) on the expression of these genes by NG and HGF fibroblasts. RESULTS: Our results obtained from semi-quantitative reverse transcription-polymerase chain reactions (RT-PCR), Western blots, enzyme-linked immunosorbent assays (ELISA), and enzymographies clearly demonstrated that the expression and production of type I collagen and Hsp47 were significantly higher in fibroblasts from HGF than from NG, whereas MMP-1 and MMP-2 expression and production were lower in fibroblasts from HGF patients. Addition of TGF-beta1 and IL-6, which are produced in greater amounts by HGF fibroblasts, promoted an increase in type I collagen and Hsp47 and a decrease in MMP-1 and MMP-2 expression. IFN-gamma reduced both type I collagen and Hsp47 expression, whereas it had a slight effect on the expression of MMP-1 and MMP-2. CONCLUSION: These patterns of expression and production suggest that enhanced TGF-beta1 and IL-6 production simultaneously increase the synthesis and reduce the proteolytic activities of fibroblasts from patients with HGF, which may favor the accumulation of extracellular matrix observed in patients with this condition.

Sec61alpha synthesis is enhanced during translocation of nascent chains of collagen type IV in F9 teratocarcinoma cells after retinoic acid treatment.

Nascent procollagen peptides and other secretory proteins are transported across the endoplasmic reticulum (ER) membrane through a protein-conducting channel called translocon. Sec61alpha, a multispanning membrane translocon protein, has been implicated as being essential for translocation of polypeptide chains into the cisterns of the ER. Sec61alpha forms a protein complex with collagen and Hsp47, an ER-resident heat shock protein that binds specifically to collagen. However, it is not known whether Sec61alpha is ubiquitously produced in collagen-producing F9 teratocarcinoma cells or under heat shock treatment. Furthermore, the production and utilization of Sec61alpha may depend on the stage of cell differentiation. Cultured F9 teratocarcinoma cells are capable of differentiation in response to low concentrations of retinoic acid. This differentiation results in loss of tumorigenicity. Mouse F9 cells were grown in culture medium at 37 degrees C and 43 degrees C (heat shock treatment) treated or not with retinoic acid, and labeled in certain instances with 35S-methionine. Membrane-bound polysomes of procollagen IV were then isolated. Immunoprecipitation and Western blot analysis were performed using polyclonal antibodies against collagen IV, Hsp47 and Sec61alpha. Under retinoic acid-untreated conditions, F9 cells produced undetectable amounts of Sec61alpha. Sec61alpha, Hsp47 and type IV collagen levels were increased after retinoic acid treatment. Heat shock treatment did not alter Sec61alpha levels, suggesting that Sec61alpha production is probably not affected by heat shock. These data indicate that the enhanced production of Sec61alpha in retinoic acid-induced F9 teratocarcinoma cells parallels the increased synthesis of Hsp47 and collagen type IV.

Sec61alpha synthesis is enhanced during translocation of nascent chains of collagen type IV in F9 teratocarcinoma cells after retinoic acid treatment

Nascent procollagen peptides and other secretory proteins are transported across the endoplasmic reticulum (ER) membrane through a protein-conducting channel called translocon. Sec61alpha, a multispanning membrane translocon protein, has been implicated as being essential for translocation of polypeptide chains into the cisterns of the ER. Sec61alpha forms a protein complex with collagen and Hsp47, an ER-resident heat shock protein that binds specifically to collagen. However, it is not known whether Sec61alpha is ubiquitously produced in collagen-producing F9 teratocarcinoma cells or under heat shock treatment. Furthermore, the production and utilization of Sec61alpha may depend on the stage of cell differentiation. Cultured F9 teratocarcinoma cells are capable of differentiation in response to low concentrations of retinoic acid. This differentiation results in loss of tumorigenicity. Mouse F9 cells were grown in culture medium at 37ºC and 43ºC (heat shock treatment) treated or not with retinoic acid, and labeled in certain instances with 35S-methionine. Membrane-bound polysomes of procollagen IV were then isolated. Immunoprecipitation and Western blot analysis were performed using polyclonal antibodies against collagen IV, Hsp47 and Sec61alpha. Under retinoic acid-untreated conditions, F9 cells produced undetectable amounts of Sec61alpha. Sec61alpha, Hsp47 and type IV collagen levels were increased after retinoic acid treatment. Heat shock treatment did not alter Sec61alpha levels, suggesting that Sec61alpha production is probably not affected by heat shock. These data indicate that the enhanced production of Sec61alpha in retinoic acid-induced F9 teratocarcinoma cells parallels the increased synthesis of Hsp47 and collagen type IV