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Despite many years of intensive investigation, real biological role of SERPINB2 is largely unknown. However, recent high throughput studies suggest its function in inflammation, influence on autoimmune disorders, and modulation of processes leading to carcinogenesis. SERPINB2 expression is acutely upregulated by many different stimuli, among others by aryl hydrocarbon receptor ligands. Mechanisms of regulation of SERPINB2 expression, involvement of the gene in processes leading to inflammation or carcinogenesis, and its interplay with aryl hydrocarbon receptor are subject of present review.

The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. In this study, the effects of administration of β-naphthoflavone (BNF), a potent AhR ligand, on the expression of AhR-dependent genes were examined by microarray and qPCR analysis in both, differentiated and undifferentiated HepaRG cell lines. To prove that BNF-induced changes of investigated genes were indeed AhR-dependent, we knock down the expression of AhR by stable transfection of HepaRG cells with shRNA. Regardless of genetical identity, our results clearly demonstrate different expression profiles of AhR-dependent genes between differentiated and undifferentiated HepaRG cells. Genes involved in metabolism of xenobiotics constitute only minute fraction of all genes regulated by AhR in HepaRG cells. Participation of AhR in induction of expression of genes associated with regulation of apoptosis or involved in cell proliferation as well as AhR-dependent inhibition of genes connected to cell adhesion could support suggestion of involvement of AhR not only in initiation but also in progression of carcinogenesis. Among the AhR-dependent genes known to be involved in metabolism of xenobiotics, cytochromes P4501A1 and 1B1 belong to the most inducible by BNF. On the contrary, expression of GSTA1 and GSTA2 was significantly inhibited after BNF treatment of HepaRG cells. Among the AhR-dependent genes that are not involved in metabolism of xenobiotics SERPINB2, STC2, ARL4C, and TIPARP belong to the most inducible by BNF. Our results imply involvement of Ah receptor in regulation of CYP19A1, the gene-encoding aromatase, and an enzyme responsible for a key step in the biosynthesis of estrogens. Electronic supplementary material The online version of this article (doi:10.1007/s11010-016-2862-3) contains supplementary material, which is available to authorized users.

Aryl hydrocarbon receptor (AhR) is a highly conserved ligand-activated transcription factor with high affinity to aromatic planar compounds, such as β-naphthoflavone (BNF), benzo[a]pyrene (BaP) or dioxin (TCDD). After binding the ligand, AhR triggers induction of the expression of phase I and phase II drug-metabolizing genes, together with numerous other genes that are not directly involved in the metabolism of xenobiotics. Several studies have shown that AhR plays a role in tumor initiation, promotion and progression, but the molecular mechanisms involved in these processes are not fully understood. A previous study from our laboratory indicated that the SERPINB2 gene is presumably regulated by AhR. To prove that such induction is really AhR-dependent, in the present study we knocked down the expression of AhR by stable transfection of a laryngeal squamous cell carcinoma cell line (UT-SCC-34) with shRNA, resulting in 92% reduction of BNF-induced expression of SERPINB2. However, in silico analysis did not reveal AhR-dependent responsive elements in the promoter of the SERPINB2 gene. Therefore, to address this problem, we have used cycloheximide, an inhibitor of translation, and our results clearly indicate that an additional, newly synthesized protein is involved in AhR-dependent induction of SERPINB2 expression by BNF. So, to exclude that AhR binds to the putative xenobiotic-responsive elements (XREs) localized upstream of the SERPINB2 gene, we performed chromatin immunoprecipitation assays. As expected, we found no direct binding of AhR to its responsive elements in the vicinity of the SERPINB2 gene, further demonstrating the indirect SERPINB2 induction by AhR. However, the further analysis demonstrated that the expression of the enhancer RNA encoded by the region of DNA 20 kbp upstream from the SERPINB2 gene was AhR-dependent. Although AhR-mediated SERPINB2 induction clearly requires the synthesis of an additional protein, the kinetics of SERPINB2 induction is as fast as the kinetics of CYP1A1 and CYP1B1 induction (both genes directly regulated by AhR). Therefore, given previous studies regarding the induction of SERPINB2 expression by bacterial lipopolysaccharides (LPS), we think that, similarly, the interaction with pause-release proteins may be responsible for AhR-dependent regulation of SERPINB2 expression.

The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. AhR is ligand activated transcription factor with high affinities for aromatic planar compounds such as β-naphthoflavone (BNF), 3-methylcholanthrene (3-MC), benzo[a]pyrene (BaP) or dioxin (TCDD). After binding appropriate ligand, AhR trigger induction of expression of some phase I and phase II drug metabolizing genes together with numerous other genes. One of such gene appear to be polymerase (DNA directed) kappa (Polκ). Polκ gene encodes newly identified low fidelity DNA polymerase. The enzyme bypasses benzo[a]pyrene-N2-dG lesions in a mostly error free manner by incorporating predominantly dC opposite the bulky lesions. It was demonstrated that AhR activation increases expression of the mouse Polκ gene and probably human POLK gene. In this study we examined the effect of i.p. administration of different AhR ligands on the expression of Polκ, RNA polymerase II polypeptide A (PolR2a) and cytochrome P450 1B1 (CYP1B1), the genes controlled by AhR in Sprague-Dawley rat liver. Quantitative real-time RT-PCR analysis revealed significant induction in the mRNA expression levels of Polκ and PolR2a following BNF treatment. Time courses of mRNA expression after treatment with BNF were similar in both genes, with maximal increases at 8h after treatment. The maximal induction of CYP1B1 and CYP1A1 expression was observed after 24 and 8h after BNF injection, respectively. TCDD treatment caused the significant increase in the mRNA level of CYP1B1 at 72h after administration of the ligand but no effect on Polκ and PolR2a mRNA expression was observed. These results confirm connection between AhR and Polκ, and strongly suggest that AhR up-regulates the mRNA transcription of PolR2a as well. However physiological importance of AhR dependent regulation of PolR2a expression must be further elucidated.

Although down-regulation of GNG7 in cancer was reported before, its role in carcinogenesis is poorly understood. It belongs to a family of large G-proteins that may be involved in cell-contact-induced growth arrest and function in tumor suppression. In the present study, we stained immunohistochemically 188 tumors derived from larynx or floor of the mouth for GNG7 protein and confronted it with clinicopathologic data. Moreover, we performed bisulfite pyrosequencing to analyze GNG7 promoter methylation. We identified recurrent loss of GNG7 protein expression in 68/188 (36%) cases and promoter hypermethylation in (42/98; 43%) primary tumors, predominantly in young patients (p

Thirteen laryngeal squamous cell carcinoma cell lines were recently studied by array comparative genomic hybridization (array-CGH) in order to identify recurrent DNA copy number alterations in the tumor genome. A highly amplified region 22q11.2 was found in two of the thirteen cell lines. Two established oncogenes CRKL and MAPK1 are localized in this region, but only CRKL was amplified in both cell lines. Therefore, to check if amplification of either CRKL or MAPK1 genes may be important in the pathogenesis of laryngeal squamous cell carcinoma, the DNA copy number and mRNA expression were measured in a cohort of 17 LSCC cell lines by quantitative real-time PCR (qPCR). For the CRKL gene gains of the copy number were found in 3/17 cell lines, while overexpression was found in 6/17 cell lines. Gains in the copy number for the MAPK1 gene were found in 1/17 cell lines, but overexpression was not detected in any cell line. A highly significant correlation between DNA copy number and expression for CRKL gene, but not for MAPK1 gene was established using the Pearson test. Thereafter, 46 primary samples of laryngeal cancer were tested by qPCR to check for possible gains in copy number of the CRKL gene. Gains were found in 3/46 cases. These results suggest that CRKL, but not MAPK1 is the target oncogene of the rare but recurrent amplification at 22q11.2 in laryngeal squamous cell carcinoma.

Many classical tumor suppressor genes (TSG) were identified by delineation of bi-allelic losses called homozygous deletions. To identify systematically homozygous deletions in laryngeal squamous cell carcinoma (LSCC) and to unravel novel putative tumor suppressor genes, we screened 10 LSCC cell lines using high resolution array comparative genomic hybridization (arrayCGH) and array based expression analysis. ArrayCGH identified altogether 113 regions harboring protein coding genes that showed strong reduction in copy number indicating a potential homozygous deletion. Out of the 113 candidate regions, 22 novel homozygous deletions that affected the coding sequences of 15 genes were confirmed by multiplexPCR. Three genes were homozygously lost in two cell lines: PCDH17/PCH68, PRR20, and PTPRD. For the 15 homozygously deleted genes, four showed statistically significant downregulation of expression in LSCC cell lines as compared with normal human laryngeal controls. These were ATG7 (1/10 cell line), ZMYND11 (BS69) (1/10 cell line), PCDH17/PCH68 (9/10 cell lines), and PTPRD (7/10 cell lines). Quantitative real-time PCR was used to confirm the downregulation of the candidate genes in 10 expression array-studied cell lines and an additional cohort of cell lines; statistical significant downregulation of PCDH17/PCH68 and PTPRD was observed. In line with this also Western blot analyses demonstrated a complete absence of the PCDH17 and PTPRD proteins. Thus, expression profiling confirmed recurrent alterations of two genes identified primarily by delineation of homozygous deletions. These were PCDH17/PCH68, the protocadherin gene, and the STAT3 inhibiting receptor protein tyrosine phosphatase gene PTPRD. These genes are good candidates for novel TSG in LSCC. (C) 2010 Wiley-Liss, Inc.

The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. AhR together with ARNT, AhRR, HIF1alpha represent a novel basic helix-loop-helix/PAS family of transcriptional regulators. Their interplay may affect the xenobiotic response. In this study, the effect of i.p. administration of different AhR ligands on the expression of AhR, AhRR, ARNT, HIF1alpha and CYP1A1 and NAD(P)H: quinone oxidoreductase (NQO1), the enzymes controlled by AhR were examined in Sprague-Dawley rat liver. Quantitative real-time RT-PCR analysis revealed no changes in the mRNA expression of ARNT and HIF1alpha following 3-methylcholanthrene (3-MC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or beta-naphthoflavone (BNF) treatment. AhRR expression was affected by TCDD but not by BNF and 3-MC. Expression of AhR mRNA and of the markers of its activation, CYP1A1 and NQO1, was significantly increased by administration of TCDD, 3-MC and, to lower extent, BNF. These results indicate that binding of the ligands to AhR up-regulates the mRNA transcription not only of CYP1A1 and NQO1, but also of AhR itself. The level of AhR induction depends on the potency of xenobiotic metabolizing enzymes inducer.

Several naturally occurring plant phenols were shown to inhibit the mutagenicity and/or tumorigenicity of chemical carcinogens, including polycyclic aromatic hydrocarbons (PAHs). In this study, the effect of the topical application of three structurally diverse phenolic acids and trihydroxystilbene, resveratrol, on epidermal aryl hydrocarbon hydroxylase (AHH), phase II enzymes, as well as the binding of benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA) to epidermal DNA were compared. The single, topical application of 8 and 16 mumol of protocatechuic or chlorogenic acid increased the activity of AHH by 10-30%, whereas resveratrol in a dose of 16 mumol almost completely (99%) inhibited the enzyme activity. Phenolic acids also increased the activities of phase II enzymes. Resveratrol did not affect the glutathione S-transferase activity but induced UDP glucuronosyltransferase (by approximately 100-150%) and to a lesser extent NAD(P)H:quinone oxidoreductase. In a dose of 16 micromol all phenolic acids afforded 40-50% inhibition of covalent benzo[a]pyrene-diol-epoxide (B[a]PDE) binding to DNA. Resveratrol had no effect on B[a]PDE adduct formation but reduced the levels of all the major DMBA adducts. Phenolic acids, particularly tannic acid, mostly affected the formation of syn- and anti-DMBADE dAdo adducts. These results indicate that both the modulation of carcinogen activating enzymes and the prevention of their ultimate metabolites binding to DNA by naturally occurring phenolics are involved in the antitumorigenic activity of these compounds. For phenolic acids, however, their interactions with reactive PAH metabolites and/or blocking of a specific binding site in a genome seem more important. Derivatives of stilbene, such as resveratrol, affect DNA adduct formation and thus the initiation of tumorigenesis through the interaction with the Ah receptor rather than the scavenging active metabolites.

Obtaining a good quality of RNA from small population of cells remain an issue. Isolation for a special anatomic location such as inner ear placed in the temporal bone become a challenge, especially in terms of time needed for isolation of living tissue from the bone, which is a key factor to preserve the RNA. Due to limited accessibility to the technologies such as laser dissection, we present a simplified procedure for isolation of good quality of RNA from the inner ear for further studies.

The aryl hydrocarbon receptor (AhR) mediates a variety of biological responses to ubiquitous environmental pollutants. In this study the effect of administration of β-naphthoflavone (BNF), potent AhR ligand, on the expression of AhR, AhRR, CYP1A1, CYP1A2, CYP1B1, NQO1, GSTA1, ALDH3A1 and UGT1A genes encoding the enzymes controlled by AhR were examined in thirteen laryngeal tumor cell lines and in HepaRG cell line. The analyzed cell lines were derived from patients with squamous laryngeal cancer, with history of cigarette smoking and without signs of human papillomavirus types 16 and 18 infection in investigated cells. Quantitative real-time RT-PCR analysis revealed huge interindividual differences in expression of genes from AhR regulatory network. Our results strongly suggest predominant effect of DNA methylation on induction of CYP1A1 expression by AhR ligands as well. Our results indicate that differentiated HepaRG cell line appeared to be very good substitute for human liver in studies on xenobiotic metabolism by AhR regulated enzymes.

beta-Naphthoflavone (beta-NF) is a widely used inducer of phase-I and phase-II enzymes controlled by aryl hydrocarbon receptor (AhR). Studies of competitive binding with (3)H-labelled 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 3-methylcholanthrene (3-MC) and benzo[a]pyrene (B[a]P) have shown that beta-NF is a high-affinity ligand for AhR and also for polycyclic aromatic hydrocarbon (PAH)-binding protein, both soluble proteins of rat liver in 8 S and 4 S fractions, respectively, of sucrose gradients. This study examined binding of [(3)H]beta-NF to liver cytosolic proteins of female Sprague-Dawley rats. Treatment of rats with beta-NF, 3-MC, TCDD or alpha-naphthoflavone (alpha-NF) increased the specific [(3)H]beta-NF binding to liver cytosol up to 125-fold that of vehicle (corn oil)-treated rats (

We reinvestigated rearrangements occurring in region q13 of chromosome 11 aiming to: (i) describe heterogeneity of the observed structural alterations, (ii) estimate amplicon size and (iii) identify of oncogenes involved in laryngeal cancer progression as potential targets for therapy. The study included 17 cell lines derived from laryngeal cancers and 34 specimens from primary laryngeal tumors. The region 11q13 was analyzed by fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and gene expression microarray. Next, quantitative real time PCR was used for chosen genes to confirm results from aCGH and gene expression microarray. The observed pattern of aberrations allows to distinguish three ways, in which gain and amplification involving 11q13 region may occur: formation of a homogeneously staining region; breakpoints in/near 11q13, which lead to the three to sevenfold increase of the copy number of 11q13 region; the presence of additional copies of the whole chromosome 11. The minimal altered region of gain and/or amplification was limited to ~1.8 Mb (chr.11:69,395,184–71,209,568) and comprised mostly 11q13.3 band which contain 12 genes. Five, out of these genes (CCND1, ORAOV1, FADD, PPFIA1, CTTN) had higher expression levels in comparison to healthy controls. Apart from CCND1 gene, which has an established role in pathogenesis of head and neck cancers, CTTN, ORAOV1 and FADD genes appear to be oncogene-candidates in laryngeal cancers, while a function of PPFIA1 requires further studies.

Mutations in mitochondrial DNA have been reported as associated with non-syndromic and aminoglycoside-induced hearing loss. In the present study, we have performed mutational screening of entire 12S rRNA gene in 250 unrelated patients with non-syndromic and aminoglycoside-induced hearing loss. Twenty-one different homoplasmic sequence variants were identified, including eight common polymorphisms, one deafness-associated mutation m.1555 A>G and three putatively pathogenic variants: m.669 T>C, m.827 A>G, m.961 delT+C(n)ins. The incidence of m.1555 A>G was estimated for 3.6% (9/250); however, where aminoglycoside exposure was taken as a risk factor, the frequency was 5.5% (7/128). Substitution m.669 T>C was identified only in patients with hearing impairment and episode of aminoglycoside exposure, which may suggest that such additional risk factors must appear to induce clinical phenotype. Moreover, two 12S rRNA sequence variants: m.988 G>A and m.1453 A>G, localized at conserved sites and affected RNA secondary structure, may be new candidates for non-syndromic and aminoglycoside-induced hearing loss associated mutations.

A profound induction of a 4S β-naphthoflavone (BNF)-binding protein, cytochrome P450 1A1 (CYP1A1) and NAD(P)H:quinone oxidoreductase (NQO1) activities was determined in the livers of Sprague–Dawley rats following intraperitoneal administration of BNF. Time-course of this induction differed for CYP1A1 and NQO1 activities, suggesting independent regulation of the phase I and II enzymes of xenobiotic metabolism. Time-course of the induction of CYP1A1 and BNF-binding activities was similar, suggesting that regulation of a 4S BNF- binding protein is associated with that of the CYP1A1 enzyme activity. The BNF specific binding to a 4S protein was inhibited by exogenous (BNF) and endogenous (indirubin and indigo) ligands for the aryl hydrocarbon receptor.

The online version of the original article can be found underdoi:10.1007/s11033-012-1465-7.M. Szaumkessel (&) D. Brauze M. Rydzanicz K. SzyfterInstitute of Human Genetics, Polish Academy of Sciences,ul. Strzeszynska 32, 60-479 Poznan, Polande-mail: marcinsz@man.poznan.plM. Karlik K. Szyfter W. Szyfter M. Wro´belDepartment of Otolaryngology, Poznan University of MedicalSciences, Poznan, Polande-mail: wrobmac@ump.edu.pl

1. Institute of Human Genetic, Polish Academy of Sciences, Poznan, Poland 2. Department of Otolaryngology, Poznan University of Medical Sciences, Poland 3. Institute of Human Genetics, University Hospital Schleswig-Holstein Campus Kiel, Germany 4. Department of OtorhinolaryngologyeHead and Neck Surgery and Department of Medical Biochemistry, Turku University Central Hospital and Turku University, Finland