Redox homeostasis in human renal cells that had been treated with amphotericin B in combination with selected 1,3,4-thiadiazole derivatives.

BACKGROUND: The use of amphotericin B (AmB) in the therapy of systemic mycosis is associated with strong side effects, including nephrotoxicity, and hepatotoxicity. Therefore, agents that can reduce the toxic effects of AmB while acting synergistically as antifungal agents are currently being sought. 1,3,4-thiadiazole derivatives are promising compounds that have an antifungal activity and act synergically with AmB. Such combinations might allow the dose of AmB, which is essential for preventing patients from having serious side effects, to be decreased. This might result from the antioxidant properties of 1,3,4-thiadiazoles. Thus, the aim of the study was to investigate redox homeostasis in human renal proximal tubule epithelial cells (RPTEC) after they had been treated with AmB in combination with 1,3,4-thiadiazole derivatives. METHODS: Cellular redox homeostasis was assessed by investigating the total antioxidant capacity (TAC) of cells, the malondialdehyde (MDA) concentration, and the activity of antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). TAC was measured using an ABTS method. The MDA concentration, and the activity of SOD, GPX, and CAT were determined spectrophotometrically using commercially available assays. Additionally, the antioxidant defense system-related gene expression profile was determined using oligonucleotide microarrays (HG-U133A 2.0). Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to confirm the microarray results. RESULTS: Amphotericin B and selected 1,3,4-thiadiazole derivatives had a significant effect on the total antioxidant capacity of the RPTEC cells, and the activity of the antioxidant enzymes. We also revealed that the effect of thiadiazoles on the SOD and CAT activities is dependent on the treatment of RPTEC cells with AmB. At the transcriptional level, the expression of several genes was affected by the studied compounds and their combinations. CONCLUSIONS: The results confirmed that thiadiazoles can stimulate the RPTEC cells to defend against the oxidative stress that is generated by AmB. In addition, together with the previously demonstrated synergistic antifungal activity, and low nephrotoxicity, these compounds have the potential to be used in new therapeutic strategies in the treatment of fungal infections.

The Influence of Betulin Derivatives EB5 and ECH147 on the Expression of Selected TGFß Superfamily Genes, TGFß1, GDF15 and BMP2, in Renal Proximal Tubule Epithelial Cells.

Betulin derivatives are proposed to serve as an alternative to the drugs already established in oncologic treatment. Drug-induced nephrotoxicity leading to acute kidney injury frequently accompanies cancer treatment, and thus there is a need to research the effects of betulin derivatives on renal cells. The objective of our study was to assess the influence of the betulin derivatives 28-propynylobetulin (EB5) and 29-diethoxyphosphoryl-28-propynylobetulin (ECH147) on the expression of TGFß1, BMP2 and GDF15 in renal proximal tubule epithelial cells (RPTECs) cultured in vitro. The changes in mRNA expression and copy numbers were assessed using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) and the standard curve method, respectively. An enzyme-linked immunosorbent assay (ELISA) was used to evaluate the effect of the betulin derivatives on the protein concentration in the culture media's supernatant. The assessment of the betulin derivatives' influence on gene expression demonstrated that the mRNA level and protein concentration did not always correlate with each other. Each of the tested compounds affected the mRNA expression. The RT-qPCR analyses showed that EB5 and ECH147 induced effects similar to those of betulin or cisplatin and resulted in a decrease in the mRNA copy number of all the analyzed genes. The ELISA demonstrated that EB5 and ECH147 elevated the protein concentration of TGFß1 and GDF15, while the level of BMP2 decreased. The concentration of the derivatives used in the treatment was crucial, but the effects did not always exhibit a simple linear dose-dependent relationship. Betulin and its derivatives, EB5 and ECH147, influenced the gene expression of TGFß1, BMP2 and GDF15 in the renal proximal tubule epithelial cells. The observed effects raise the question of whether treatment with these compounds could promote the development of renal fibrosis.

Changes in the Expression Profile of Pyroptosis-Related Genes in Senescent Retinal Pigment Epithelial Cells after Lutein Treatment.

Retinal pigment epithelium (RPE) is a specialized structure essential for proper vision, which is constantly exposed to oxidative damage. With aging, this damage accumulates within the RPE cells, causing various diseases, including age-related macular degeneration (AMD). Numerous antioxidant substances are used to prevent this process in humans, including lutein. This study aims to determine the differences in the expression patterns of pyroptosis genes in senescent human retinal pigment epithelial cell line ARPE-19 exposed to lutein. Changes in the expression of pyroptosis-related genes were assessed by oligonucleotide microarrays, and the results were validated by real-time RT-qPCR. The microarray analysis showed seven transcripts were differentially expressed both in the H2O2-treated cells versus the controls and in the lutein/H2O2-treated cells compared to the H2O2-treated cells (FC > 2.0). Depending on the used lutein, H2O2, or co-treatment of ARPE-19 cells, statistically significant differences in the expression of TXNIP, CXCL8, BAX, and CASP1 genes were confirmed by the RT-qPCR (p < 0.05). A STRING database analysis showed that the proteins encoded by the analyzed genes form a strong interaction network (p < 0.001). These data indicate that lutein modulates the expression level of pyroptosis-related genes, which may be useful for the development of new methods preventing pyroptosis pathway activation in the future.

Effect of Antibiotic Amphotericin B Combinations with Selected 1,3,4-Thiadiazole Derivatives on RPTECs in an In Vitro Model.

4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (C1) and 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl] benzene1,3-diol (NTBD) are representative derivatives of the thiadiazole group, with a high antimycotic potential and minimal toxicity against normal human fibroblast cells. The present study has proved its ability to synergize with the antifungal activity of AmB. The aim of this work was to evaluate the cytotoxic effects of C1 or NTBD, alone or in combination with AmB, on human renal proximal tubule epithelial cells (RPTECs) in vitro. Cell viability was assessed with the MTT assay. Flow cytometry and spectrofluorimetric techniques were used to assess the type of cell death and production of reactive oxygen species (ROS), respectively. The ELISA assay was performed to measure the caspase-2, -3, and -9 activity. ATR-FTIR spectroscopy was used to evaluate biomolecular changes in RPTECs induced by the tested formulas. The combinations of C1/NTBD and AmB did not exert a strong inhibitory effect on the viability/growth of kidney cells, as evidenced by the negligible changes in the apoptotic/necrotic rate and caspase activity, compared to the control cells. Both NTBD and C1 displayed stronger anti-oxidant activity when combined with AmB. The relatively low nephrotoxicity of the thiadiazole derivative combinations and the protective activity against AmB-induced oxidative stress may indicate their potential use in the therapy of fungal infections.

Composite Nanofibers Containing Multiwall Carbon Nanotubes as Biodegradable Membranes in Reconstructive Medicine.

We have tested titanium (Ti) plates that are used for bone reconstruction in maxillofacial surgery, in combination with five types of novel long-resorbable biomaterials: (i) PCL0-polycaprolactone without additives, (ii) PCLMWCNT-polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT), (iii) PCLOH-polycaprolactone doped with multiwall carbon nanotubes (MWCNT) containing ⁻OH hydroxyl groups, (iv) PCLCOOH-polycaprolactone with the addition of multiwall carbon nanotubes (MWCNT) containing carboxyl groups, and (v) PCLTI-polycaprolactone with the addition of Ti nanoparticles. The structure and properties of the obtained materials have been examined with the use of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and/or X-ray powder diffraction (XRD). Titanium BR plates have been covered with: (i) PCL0 fibers (PCL0BR-connection plates), (ii) PCLMWCNT fibers (PCLMWCNTBR-plates), (iii) PCLOH fibers (PCLOHBR-plates), (iv) PCLCOOH (PCLCOOHBR-plates), (v) PCLTI fiber (PCLTIBR-connection plates). Such modified titanium plates were exposed to X-ray doses corresponding to those applied in head and neck tumor treatment. The potential leaching of toxic materials upon the irradiation of such modified titanium plates, and their effect on normal human dermal fibroblasts (NHDF) have been assessed by MTT assay. The presented results show variable biological responses depending on the modifications to titanium plates.

Potential Mechanism of Action of Cyclosporin A in Human Dermal Fibroblasts-Transcriptomic Analysis of CYPs.

Effect of cyclosporin A (CsA) in a therapeutic concentration, on the expression of cytochrome P450 genes (CYPs), was investigated in normal human dermal fibroblast cells. The expression of 57 genes, encoding cytochrome P450 isoforms, was estimated using the microarray method. Amongst 396 normalized fluorescence signals related to cytochrome P450 activity, only 91 were strictly connected to CYPs and were analyzed using two methods: a self-organizing feature map of artificial neural networks and typical statistical analysis with significance level at p ≤ 0.05. Comparing the samples from fibroblasts cultured with CsA and those cultured without, up-regulated changes of CYP19A1, 1B1, 7A1, 7F1, 17A1 and down-regulated 2D6 gene expression were observed. The mRNAs with increased changes were in the same neuron of the self-organizing feature map. All distinguished CYPs encode monooxygenases, which plays an important role in steroids biosynthesis and metabolism. Based on the obtained results, we can conclude that CsA in therapeutic concentration changes the expression profile of CYPs in human dermal fibroblasts, especially affecting genes linked to steroids synthesis and/or metabolism. It shows the potential mechanism of action of CsA in human dermal fibroblast cells.

The Capability to Forecast Response to Therapy with Regard to The Time and Intensity of The Inflammatory Process in vitro in Dermal Fibroblasts Induced by IL-12.

BACKGROUND: The aim of the study was to evaluate the changes in the expression of genes - TNF-α, IFN-γ, depending on the time and concentration of IL-12 used to expose the Normal Human Dermal Fibroblast (NHDF) cells. METHODS: The material for the study included NHDF exposed to IL-12 in various IL-12 concentrations (1/10/100 ng/ml) and exposure time 0.5h, 1h, 2h, 4h, 8h, 24h, compared to the control. Changes in gene expression were evaluated with the use of the RTqPCR method. The statistical analysis was performed with the use of Statistica 12.5 PL The role of genes of the JAK-STAT signaling pathway in the induction of the inflammatory process was determined with the use of the PANTHER overrepresentation test. RESULTS: Regardless of the time of NHDF exposure and the IL-12 concentrations used, we observed changes in the expressions of TNF-α and IFN-γ. Increased expression of one transcript involves the decreased expression of the other. We assessed that genes of the JAK-STAT signaling pathway are engaged in 6 biological processes, 8 molecular functions, 6 signaling pathways. CONCLUSION: The conducted studies indicate that conclusions about the intensity of the inflammatory process, and the efficacy of the anti-cytokine therapeutic strategy, may be made on the basis of the TNF-α, IFN-γ expression.

Amphotericin B-copper (II) complex alters transcriptional activity of genes encoding transforming growth factor-beta family members and related proteins in renal cells.

BACKGROUND: Several chemical modifications have been developed to overcome the toxicity of amphotericin B (AmB). Oxidized forms of AmB (AmB-ox), which may occur in patient's circulation during therapy, are as toxic as AmB. Complexes with copper (II) ions (AmB-Cu2+) have been reported to be less toxic to human cells. Previous studies showed that AmB changed the expression of transforming growth factor-beta (TGF-ß). Therefore, the objective of this study was to investigate the influence of AmB and its modified forms on the expression of genes encoding for TGF-ß family members and related proteins in renal cells. METHODS: Human renal proximal tubule cells (RPTEC) were treated with AmB-Cu2+, AmB, or the oxidized form AmB-ox. The expression of TGF-ß family members and related genes was determined using oligonucleotide microarrays. TGF-ß1 protein level was determined using ELISA method. The mRNA level of TGF-ß isoforms, TGF-ß receptors and differentiating genes was evaluated by real-time RT-qPCR. RESULTS: AmB-Cu2+ increased the mRNA levels of TGF-ß1 and TGF-ß2 isoforms and two genes encoding receptors: TGFBR1 and TGFBR2. TGF-ß1 protein level in culture medium was not increased after stimulation with AmB-Cu2+. Microarray analysis revealed changes in both pro-fibrotic and anti-fibrotic genes. CONCLUSIONS: These results suggest that AmB-Cu2+ may induce repair mechanisms in renal proximal tubule cells via changes in the expression of genes involved in intracellular signaling.

Differential expression of microRNAs and their predicted targets in renal cells exposed to amphotericin B and its complex with copper (II) ions.

MicroRNAs (miRNAs) have been reported to regulate essential biological processes, and their expression was shown to be affected by pathological processes and drug-induced toxicity. Amphotericin B (AmB) can cause liver and kidney injury, but a recently developed complex of AmB with copper (II) ions (AmB-Cu2+) exhibits a lower toxicity to human renal cells while retaining a high antifungal activity. The aim of our study was to assess AmB-Cu2+-induced changes in the miRNA profile of renal cells and examine which biological processes are significantly affected by AmB-Cu2+. We also aimed to predict whether differentially expressed miRNAs would influence observed changes in the mRNA profile. miRNA and mRNA profiles in normal human renal proximal tubule epithelial cells (RPTEC) treated with AmB-Cu2+ or AmB were appointed with the use of microarray technology. For differentially expressed mRNAs, the PANTHER overrepresentation binomial test was performed. miRNA target interactions (MTIs) were predicted using the miRTar tool. The mRNA profile was much more strongly affected than the miRNA profile, in both AmB-Cu2+- and AmB-treated cells. AmB-Cu2+ influenced both the miRNA and mRNA profiles much more strongly than AmB. The most affected biological processes were intracellular signal transduction (AmB-Cu2+) and signal transduction (AmB). Only a few interactions between differentiating miRNAs and mRNAs were found. Changes in the profiles of genes involved in signal transduction and intracellular signal transduction may not result from interactions with differentially expressed miRNAs. Changes in the miRNA profile suggest the possible influence of tested drugs on the regulation of fibrosis via a miRNA-dependent mechanism.

Transforming growth factor ß-related genes in human retinal pigment epithelial cells after tacrolimus treatment.

BACKGROUND: The transforming growth factor ß (TGFß) family plays an important role in the pathogenesis of many diseases, including fibrotic pathologies of the eyes. The difficulties of surgical procedures contribute to the search for new treatment strategies for proliferative vitreoretinopathy. Therefore, the aim of this study was to investigate the expression profile of TGFß isoforms, their receptors, and TGFß-related genes in human retinal pigment epithelial cells (RPE) after tacrolimus (FK-506) treatment in the presence or absence of lipopolysaccharide (LPS)-induced inflammation. METHODS: The expression profile was analyzed using oligonucleotide microarrays and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) techniques. RESULTS: Analysis using oligonucleotide microarrays revealed 20 statistically significant differentially expressed TGFß-related genes after LPS treatment in relation to control cells, and after tacrolimus and LPS treatment in relation to LPS-treated cells. Moreover, our results showed that mRNA levels for TGFß2 and TGFßR3 after tacrolimus treatment, and for TGFßR3 after tacrolimus and LPS treatment in RPE cells were decreased. In turn, in the presence of LPS-induced inflammation, TGFß2 mRNA level was increased. CONCLUSIONS: These results can be important in regard to the treatment of proliferative vitreoretinopathy, pathogenesis of which is associated with processes regulated by TGFß, such as inflammation, proliferation, epithelial-mesenchymal transition (EMT), and fibrosis.

Microarray analysis of retroviral restriction factor gene expression in response to porcine endogenous retrovirus infection.

Microarray analysis has been used for screening genes involved in specific biological processes. Many studies have shown that restriction factors may play an important role in xenotransplantation safety, but it is still unclear whether porcine endogenous retroviruses (PERVs) may be inhibited by these factors. Therefore, the present study focused on the microarray analysis retroviral restriction factors gene expression in normal human dermal fibroblasts (NHDFs) in response to PERVs. PERV infectivity was analyzed using a co-culture system of NHDFs and porcine kidney epithelial cells (PK15 cell line). Detection of the copy number of PERV A, PERV B DNA and PERV A, PERV B RNA was performed using real-time Q-PCR and QRT-PCR. The expression of retroviral restriction factor genes was compared between PERV-infected and uninfected NHDF cells using oligonucleotide microarray. The up-regulated transcripts were recorded for two differentially expressed genes (TRIM1, TRIM16) with the use of GeneSpring platform and Significance Analysis of Microarrays. In conclusion, our results suggest that the TRIM family may play an important role in innate immunity to PERV infection. These results can allow a better understanding of restriction mechanism of PERV infection and probably design molecularly targeted therapies in the future. Moreover, knowledge of retroviral restriction factor gene expression in human cells may help to uncover strategies for determining their exact function. Microarray analyses seem to be promising in biological and biomedical studies, however, these results should be further confirmed by research conducted at the protein level.

Porcine endogenous retrovirus infection changes the expression of inflammation-related genes in lipopolysaccharide-stimulated human dermal fibroblasts.

BACKGROUND: The present study focuses on explaining the interaction between porcine endogenous retroviruses (PERVs) and human cells in inflammatory conditions. The differences in expression of selected inflammation-related genes in human dermal fibroblasts (NHDF) infected with PERVs with and without lipopolysaccharide stimulation were identified. MATERIAL AND METHODS: The PERV infectivity was analyzed using a co-culture of NHDF and PK15 cells. Quantification of PERV A, B DNA and PERV A, B RNA was performed by real-time QPCR and QRT-PCR. The analysis of the expression profile was performed using HG-U133A 2.0 oligonucleotide microarrays. RESULTS: PERV infection of NHDF cells with LPS stimulation resulted in a statistically significant decrease in the copy number of PERV A DNA, and an increase in the copy number of PERV A RNA compared to fibroblasts without stimulation. There was no statistically significant difference between the copy number of PERV B RNA of LPStreated and untreated NHDF cells. Typing of differentiation genes was performed in a panel of 571 selected transcripts of inflammation-related genes. Among all studied genes, 23 were differentially regulated with a change greater that 1.1-fold and p<0.05 in all studied groups. Of these 23 genes, 3 were found to be regulated by more than 2.0-fold at least in 2 studied groups (IL6, IL8, and IL33). CONCLUSIONS: The interaction between porcine endogenous retroviruses and human cells changes in inflammatory conditions. PERV infection of NHDF cells may alter the expression of inflammation-related genes. Further investigations concerning PERV infection of human cells in different conditions seem to be necessary.

Quantitative analysis of porcine endogenous retroviruses in different organs of transgenic pigs generated for xenotransplantation.

The pig appears to be the most promising animal donor of organs for use in human recipients. Among several types of pathogens found in pigs, one of the greatest problems is presented by porcine endogenous retroviruses (PERVs). Screening of the source pig herd for PERVs should include analysis of both PERV DNA and RNA. Therefore, the present study focuses on quantitative analysis of PERVs in different organs such as the skin, heart, muscle, and liver and blood of transgenic pigs generated for xenotransplantation. Transgenic pigs were developed to express the human α-galactosidase, the human α-1,2-fucosyltransferase gene, or both genetic modifications of the genome (Lipinski et al., Medycyna Wet 66:316-322, 2010; Lipinski et al., Ann Anim Sci 12:349-356, 2012; Wieczorek et al., Medycyna Wet 67:462-466, 2011). The copy numbers of PERV DNA and RNA were evaluated using real-time Q-PCR and QRT-PCR, respectively. Comparative analysis of all PERV subtypes revealed the following relationships: PERV A > PERV B > PERV C. PERV A and B were found in all samples, whereas PERV C was detected in 47 % of the tested animals. The lowest level of PERV DNA was shown in the muscles for PERV A and B and in blood samples for PERV C. The lowest level of PERV A RNA was found in the skin, whereas those of PERV B and C RNA were found in liver specimens. Quantitative analysis revealed differences in the copy number of PERV subtypes between various organs of transgenic pigs generated for xenotransplantation. Our data support the idea that careful pig selection for organ donation with low PERV copy number may limit the risk of retrovirus transmission to the human recipients.

Degradation effect of diepoxide fixation on porcine endogenous retrovirus DNA in heart valves: molecular aspects.

PURPOSE: Xenotransplantations of porcine cells, tissues, and organs involve a risk of zoonotic viral infections in recipients, including by porcine endogenous retroviruses (PERVs), which are embedded the genome of all pigs. An appropriate preparation of porcine heart valves for transplantation can prevent retroviral infection. Therefore, the present study focuses on the effect of epoxy compounds and glutaraldehyde on the PERV presence in porcine heart valves prepared for clinical use. METHODS: Porcine aortic heart valves were fixed with ethylene glycol diglycidyl ether (EDGE) at 5 °C and 25 °C as well as with glutaraldehyde (GA) for 4 weeks. Salting out was used to isolate genomic DNA from native as well as EDGE- and GA-fixed fragments of valves every week. Quantification of PERV-A, PERV-B, and PERV-C DNA was performed by real-time quantitative polymerase chain reaction (QPCR). RESULTS: All subtypes of PERVs were detected in native porcine aortic heart valves. The reduction of the PERV-A, PERV-B, and PERV-C DNA copy numbers was observed in the heart valves which were EDGE-fixed at both temperatures, and in GA-fixed ones in the following weeks. After 7 and 14 days of EDGE cross-linking, significant differences between the investigated temperatures were found for the number of PERV-A and PERV-B copies. PERV DNA was completely degraded within the first week of EDGE fixation at 25 °C. CONCLUSIONS: EDGE fixation induces complete PERV genetic material degradation in porcine aortic heart valves. This suggests that epoxy compounds may be alternatively used in the preparation of bioprosthetic heart valves in future.

Quantitative Estimation of Porcine Endogenous Retrovirus Release from PK15 Cells.

The present study focuses on the assessment of porcine endogenous retrovirus (PERV) release from PK15 cells in a time dependent manner. The highest amount of PERV A RNA was detected in PK15 cells after 16 hours of culture. The highest amount of PERV B RNA was detected in PK15 cells after 20 hours. The highest amount of both subtypes RNAs was detected in culture medium after 32 hours of culture. The peaks of PERV reverse transcriptase (RT) activity were detected after 28 h of culture in PK15 cells and after 32 hours in the culture medium. The monitoring of PERV release from PK15 cell line may be useful for the evaluation of PERV replication.

Differential expression of transforming growth factor-beta isoforms in bullous keratopathy corneas.

PURPOSE: The aim of this study was to investigate transcriptional activities of genes encoding transforming growth factor (TGF)-beta isoforms in bullous keratopathy corneas. METHODS: The study group consisted of 45 patients with bullous keratopathy (22 females and 23 males). The control group included 45 corneal donors (21 females and 24 males). Quantification of TGF-beta1, TGF-beta2, and TGF-beta3 mRNAs was performed by real-time quantitative reverse transcription PCR (QRT-PCR). RESULTS: TGF-beta1, TGF-beta2, and TGF-beta3 mRNAs were detected in both normal and pseudophakic bullous keratopathy (PBK) corneas. We found significantly lower transcriptional activity of TGF-beta3 mRNA in bullous keratopathy corneas compared to normal tissues. TGF-beta1 and TGF-beta2 expressions were at the same level in both PBK and healthy corneas. CONCLUSIONS: Downregulation of TGF-beta3 gene expression may play a significant role in molecular changes observed in bullous keratopathy.

Relevance of glutathione S-transferase M1 and cytochrome P450 1A1 genetic polymorphisms to the development of head and neck cancers.

BACKGROUND: Cytochrome P450 (CYP) and glutathione S-transferase (GST) gene variants have been intensively investigated for their implication in the development of different neoplasms. METHODS: In the present study, we analyzed genetic polymorphisms of CYP1A1, GSTM1, GSTP1, and GSTT1 in 127 head and neck cancer patients and 151 hospital controls. RESULTS: No significant increase in risk in patients with the GSTM1 null genotype (OR=1.52, 95% CI: 0.93-2.49) or CYP1A1 462Val alleles (OR=1.60, 95% CI: 0.73-3.52) or GSTP1 105Val alleles (OR=0.97, 95% CI: 0.59-1.58) was observed. The GSTT1 null genotype was found in 30.5% of the controls and 21.3% of the head and neck cancer patients (p=0.15). The estimated head and neck cancer risk for the combination of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with either GSTP1 Ile105Val or Val105Val genotype (OR=2.89, 95% CI: 0.71-11.71) and for the combination of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with GSTT1 null genotype (OR=2.62, 95% CI: 0.64-10.85) suggested the absence of the modifying effect of combined variant alleles on head and neck cancer susceptibility. The joint effect of either CYP1A1 Ile462Val or CYP1A1 Val462Val genotype with GSTM1 null genotype significantly increased the risk of head and neck cancer (OR=7.15, 95% CI: 1.49-34.32). CONCLUSIONS: Our findings corroborate metabolic genes interactions, especially for CYP1A1 462Val alleles and GSTM1 homozygous deletion, in the development of head and neck cancer in the investigated population groups in Poland.