Jacek Kabziński

An association selected polymorphisms of XRCC1, OGG1 and MUTYH gene and the level of efficiency oxidative DNA damage repair with a risk of colorectal cancer.

Oxidative damage has been implicated in the pathogenesis of colorectal cancer (CRC). The base excision repair (BER) pathway is the major DNA repair pathway for oxidative DNA damage and genetic variation associated with impaired BER might thus increase a risk of CRC. In this work, we evaluated associations between the repair efficiency of oxidative DNA lesions and single-nucleotide polymorphisms of BER genes: the 194Trp/Arg and the 399Arg/Gln XRCC1, the 326Ser/Cys OGG1 and the 324Gln/His MUTYH and CRC occurrence in a Polish population. These polymorphisms were genotyped in 182 CRC patients and 245 control subjects, using a PCR-RFLP approach. The level of oxidative damage and DNA repair capacity in lymphocytes and CRC tissue samples was evaluated by comet assay using FPG and Nth glycosidases. The 326Ser/Cys OGG1 and the 324Gln/His as well as the 324His/His MUTYH genotypes were found to be associated with an increased CRC risk, while no association was found for the XRCC1 gene polymorphisms. It was also demonstrated the reduced capacity of oxidative damage repair in CRC patients in comparison to healthy controls. Moreover, the decrease efficiency of DNA repair were correlated with the 399Gln/Gln XRCC1 and the 324His/His MUTYH genotypes occurrence in CRC patients. The results obtained in our study indicated an association of OGG1 and MUTYH genes polymorphisms involved in oxidative DNA lesions repair with the risk occurrence of colorectal cancer in Polish patients. It was also found that studied polymorphisms might affect DNA repair capacity suggesting their role in CRC pathogenesis. Finally, we conclude that BER pathway may be an important target for the diagnosis and treatment of colorectal patients.

Impaired nucleotide excision repair pathway as a possible factor in pathogenesis of head and neck cancer.

Tobacco smoking is one of the major risk factors in pathogenesis of head and neck squamous cell carcinomas (HNSCC). Many of the chemical compounds present in tobacco are well-known carcinogens which form adducts with DNA. Cells remove these adducts mainly by the nucleotide excision repair pathway (NER). NER also eliminates a broad spectrum of pyrimidine dimers (CPD) and photo-products (6-4PP) induced by UV-radiation or DNA cross-links after cisplatin anti-cancer treatment. In this study DNA damage and repair was examined in peripheral blood lymphocytes obtained from 20 HNSCC patients and 20 healthy controls as well as HTB-43 larynx and SSC-25 tongue cancer cell lines. DNA repair kinetics in the examined cells after cisplatin or UV-radiation treatment were investigated using alkaline comet assay during 240min of post-treatment incubation. MTT assay was used to analyse cell viability and the Annexin V-FITC kit specific for kinase-3 was employed to determine apoptosis after treating the cells with UV-radiation at dose range from 0.5 to 60J/m(2). NER capability was assessed in vitro with cell extracts by the use of a bacterial plasmid irradiated with UV-light as a substrate for the repair. The results show that lymphocytes from HNSCC patients and HTB-43 or SSC-25 cancer cells were more sensitive to genotoxic treatment with UV-radiation and displayed impaired DNA repair. Also evidenced was a higher rate of apoptosis induction after UV-radiation treatment of lymphocytes from the HNSCC patients and the HTB-43 cancer cells than after treatment of those from healthy donors. Finally, our results showed that there was a significant decrease in NER capacity in HTB-43 or SSC-25 cancer cells as well as in peripheral blood lymphocytes of HNSCC patients compared to controls. In conclusion, we suggest that the impaired NER pathway might be a critical factor in pathogenesis of head and neck cancer.

Tetrahydroacridine derivatives with fluorobenzoic acid moiety as multifunctional agents for Alzheimer’s disease treatment

A novel series of 9-amino-1,2,3,4-tetrahydroacridine derivatives with 2-fluorobenzoic acid or 3-fluorobenzoic acid moiety were designed, synthesized and evaluated as inhibitors of cholinesterases and aggregation of β-amyloid. In the study target compounds were very potent inhibitors of AChE and BChE. The most promising agents had higher inhibitory potency than the reference drugs which was tacrine. Ultimately, the kinetic assay shows the most active target compound 3c against AChE. Almost all of them were more potent against BChE than AChE. Compound 3c in various concentrations was tested by aggregation experiment. Inhibition of β-amyloid aggregation was 77.32% and 80.43% at 50µM and 100µM, respectively. Therefore, compound 3c is a promising agent for the treatment of AD.

An association of selected ERCC2 and ERCC5 genes polymorphisms, the level of oxidative DNA damage and its repair efficiency with a risk of colorectal cancer in polish population

Aim of this study was to analyze the correlation between polymorphisms of ERCC2 and ERCC5 genes and efficiency of repair of oxidative DNA damage with the risk of colorectal cancer (CRC). Experimental material was peripheral blood and tumor slices from CRC collected from 235 patients, 240 people without any cancer were control group. Distribution of polymorphisms of ERCC2 and ERCC5 genes in patients with CRC and healthy subjects, as well as level of oxidative DNA damage in patients and in healthy controls was performed. It has been found that the genotype 751Gln/Gln and allele Gln of ERCC2 gene and allele Asp of 312Asn/Asp polymorphism of ERCC2 gene may be associated with an increased risk of colorectal cancer. Reduced DNA repair efficiency was also demonstrated, which can confirm the important role of oxidative damage and polymorphisms of ERCC2 and ERCC5 genes in the pathogenesis of CRC. In summary, it is critical to establish a link between gene polymorphisms in repair of oxidative DNA damage with the risk of cancer. This in future will allow for diagnostic tests which will let to identify persons with high risk of developing cancer and thus effectively implement prophylactic treatment.

Association of polymorphism of Lys589Glu Exo1 gene with the risk of colorectal cancer in the Polish population.

UNLABELLED The incidence of colorectal cancer (CRC) is increasing from year to year. Despite intensive research CRC etiology remains unknown. Studies suggest that at the basis of the process of carcinogenesis can lie reduced efficiency of DNA repair mechanisms, often caused by polymorphisms in DNA repair genes. The aim of the study was to determine the relationship between gene polymorphism Lys589Glu of EXO1 gene and modulation of the risk of colorectal cancer in the Polish population. Determination of the molecular basis of carcinogenesis process and predicting increased risk will allow qualifying patients to increased risk group and including them in preventive program. MATERIAL AND METHODS The material used in study was blood collected from 130 patients diagnosed with colorectal cancer. The control group consisted of 135 healthy people. Genotyping was performed by TaqMan method. RESULTS The results obtained indicate that the genotype Lys/Glu is associated with an increased risk of colorectal cancer (OR 1.811, 95% Cl 1.031-3.181, p = 0.038). CONCLUSION On the basis of these results, we conclude that Exo1 gene polymorphism Lys589Glu may be associated with an increased risk of colorectal cancer.

New cyclopentaquinoline hybrids with multifunctional capacities for the treatment of Alzheimer’s disease

Abstract Alzheimer’s disease (AD) is the most common progressive form of brain neurodegeneration and the most prevailing cause of dementia. Unfortunately, the aetiology of AD is not completely studied but different factors are associated with the development of AD such as among others low level of acetylcholine, aggregation of β-amyloid (Aβ), hyperphosphorylated tau protein, oxidative stress, and inflammation. The study encompass organic syntheses of 2,3-dihydro-1H-cyclopenta[b]quinoline with 5,6-dichloronicotinic acid and suitable linkers derivatives as multifunctional agents for AD treatment. Afterwards self-induced amyloid beta aggregation, inhibition studies of acetylcholinesterase and butyrylcholinesterase and molecular docking studies were performed. The results showed that 3b compound exhibited the best acetylcholinesterase inhibitory activity, with IC50 value of 0.052 µM which is lower compared to references. Besides, all synthesised compounds showed good butyrylcholinesterase inhibitory activity with IC50 values from 0.071 to 0.797 µM. Compound 3b exhibited strong Aβ1–42 aggregation inhibitory effect with 25.7% at 5 µM to 92.8% at 100 µM as well as good anti-inflammatory effect. Thus, new compounds could create new perspectives for further development as a multi-target-directed agent for AD treatment. Graphical Abstract

Tetrahydroacridine derivatives with dichloronicotinic acid moiety as attractive, multipotent agents for Alzheimer's disease treatment

A novel series of 9-amino-1,2,3,4-tetrahydroacridine and 5,6-dichloronicotinic acid moiety were conjugated with different linkers. Afterwards new derivatives were evaluated as potential multifunctional acetylcholinesterase inhibitors (AChEIs), anti-Alzheimers disease (AD) drug candidates. All the compounds were synthesized and tested for capacity for the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. Specifically, the most promising derivative 3b (IC50 = 1.02 nM) had higher inhibitory potency compared to the reference drug, tacrine. Consequently, kinetic studies of 3b compound showed a mixed-type inhibition of both AChE and BuChE. Afterwards the best potent AChE inhibitor has been examined on amyloid β (Aβ) self-induced aggregation. Furthermore, 3b compound was tested in various concentrations and had moderate activity against Aβ aggregation. Inhibition of Aβ aggregation was 46.63% and 19.41% at 50 μM and 5  μM concentrations, respectively. Moreover, no cytotoxicity was observed for the mentioned concentrations. Therefore, 3b compound is a promising multipotent agent for the treatment of AD.

Impact of the Ser326Cys polymorphism of the OGG1 gene on the level of oxidative DNA damage in patients with colorectal cancer

As a result of reactive oxygen species operation, cell damage occurs in both cellular organelles and molecules, including DNA. Oxidative damage within the genetic material can lead to accumulation of mutations and consequently to cancer transformation. OGG1 glycosylase, a component of the Base Excision Repair (BER) system, is one of the enzymes that prevents excessive accumulation of 8-oxoguanine (8-oxG), the most common compound formed by oxidative DNA damage. In case of structural changes of OGG1 resulting from polymorphic variants, we can observe a significant increase in the concentration of 8-oxG. Linking individual polymorphisms to DNA repair systems with increased risk of colorectal cancer will allow patients to be classified as high risk and included in a prophylactic program. The aim of the study was to determine the level of oxidative DNA damage and to analyze the distribution of Ser326Cys polymorphism of the OGG1 gene in a group of patients with colorectal cancer and in a control group in the Polish population. MATERIAL AND METHODOLOGY DNA was isolated from the blood of 174 patients with colorectal cancer. The control group consisted of 176 healthy individuals. The level of oxidative damage was determined by analyzing the amount of 8-oxguanine using the HT 8-oxo-dG ELISA II Kit. Genotyping was performed via the TaqMan method. RESULTS The obtained results indicate that Ser326Cys polymorphism of the OGG1 gene increases the risk of RJG and is associated with significantly increased levels of 8-oxoguanine. CONCLUSIONS Based on the results obtained, we conclude that Ser326Cys polymorphism of the OGG1 gene may modulate the risk of colorectal cancer by increasing the level of oxidative DNA damage.

The Role of the XPF Gene Polymorphism (Xrcc4) Ser835ser in the Risk of Malignant Transformation of Cells in the Colorectal Cancer

UNLABELLED Participation of DNA repair systems in the pathogenesis of cancer has been a suspected phenomenon for a long time. Decreased efficiency in DNA repair translates to their ability to fix and consequently leads to mutations and the process of carcinogenesis. Linking individual polymorphisms of DNA repair systems with an increased risk of colorectal cancer will allow the classification of patients to high-risk groups and their placement under preventive program. The aim of the study was to determine the effect of XPF gene polymorphism Ser835Ser on increasing the risk of colorectal cancer in the Polish population. MATERIAL AND METHODS as the material blood collected from 146 patients diagnosed with colon cancer was used. The control group consisted of 149 healthy subjects. Genotyping was performed by Taq- Man method. RESULTS The results indicate that genotype TCC/TCT is associated with an decreased risk of colorectal cancer (OR 0.574; CI 95% 0.335-0.984; p=0.043). CONCLUSIONS Based on these results, we conclude that the XPF gene polymorphism Ser835Ser may be associated with a decreased risk of colorectal cancer.

Impact of APEX Ile64val Gene Polymorphisms of DNA Repair Ber System on Modulation of the Risk of Colorectal Cancer in the Polish Population

UNLABELLED Colorectal cancer (CRC) is one of the deadliest cancers which lie in the incidence of morbidity in second place. Intensive research is to determine and confirm the genetic basis of this disease, which is believed may have a direct relationship with the reduced efficiency of DNA repair systems. The aim of this study was to determine the effect of APEX gene polymorphism Ile64Val on increasing the risk of colorectal cancer in the Polish population. MATERIAL AND METHODS The blood samples collected from 150 patients diagnosed with colon cancer was used. The control group consisted of 150 healthy subjects. Genotyping was performed by TaqMan method. RESULTS The results indicate that genotype Ile Val is associated with an increased risk of colorectal cancer (OR 2.069; 95% CI 1,205-3,552; p = 0.008). CONCLUSIONS Based on these results, we conclude that the APEX gene polymorphism Ile64Val may be associated with an increased risk of colorectal cancer.