CYP1B1 Gene Mutation Impact on Prognosis of Primary Congenital Glaucoma

Background Primary congenital glaucoma (PCG) is a leading cause of childhood blindness in Egypt. The discovery of the underlying genetic causes has led to far greater understanding of disease mechanisms. Cytochrome P450, family 1, subfamily B, polypeptide 1(CYP1B1) gene mutations usually inherited in an autosomal recessive manner are one of the major etiologies behind PCG. Gene screening aids early diagnosis of PCG which is a key factor in managing and preventing blindness from the disease. Aim This study aims to screen for CYP1B1gene mutations in PCG patients and study its possible impact on surgical outcome of PCG. Methods Twenty-four PCG patients enrolled in this study underwent trabeculotomy, and were followed up at a 3 month interval for a year. Patients’ demographic details were recorded, and their genomic DNA was screened for CYP1B1 mutations. Genotypic impact on surgical outcome was compared between the group of patients who harbored mutations and the group unsolved with mutations. Results Six different disease causing CYP1B1 mutations were identified in 13 (54.17 %) of affected patients who exhibited more surgical failure at the last follow up visit. Conclusion This study further endorses CYP1B1 mutations as a possible etiological and prognostic factor for PCG.

Screening of West Siberian patients with primary congenital glaucoma for CYP1B1 gene mutations

Primary congenital glaucoma (PСG) is a visual organ pathology that leads to progressive blindness and poor vision in children. Its main cause is an anomaly of the anterior chamber angle. Most cases of PСG are sporadic, but familial cases with an autosomal recessive (predominantly) and autosomal dominant (rare) type of inheritance have been described. Congenital glaucoma is a rare condition (1 case per 10,000–20,000 newborns), but its prevalence is substantially higher (up to 1 case per 250 newborns) in countries where consanguineous marriages are common. Mutations in the CYP1B1 gene, which encodes cytochrome P450 1B1, are the most common cause of autosomal recessive primary congenital glaucoma. This enzyme is known to be involved in retinoic acid metabolism and is necessary for normal eye development. The aim of this work was to assess the polymorphism of the CYP1B1 gene among West Siberian patients with primary congenital glaucoma. Direct automatic Sanger sequencing of exons and adjacent splicing sites of the CYP1B1 gene was carried out in 28 people with the PCG phenotype from a West Siberian region. As a result, in the sample of the white population we examined, pathogenic variants previously described in other ethnic groups were revealed: E387K (rs55989760), R444* (rs377049098), R444Q (rs72549376), and P437L (rs56175199), as well as novel single-nucleotide deletion p.F114Lfs*38 in the CYP1B1 gene. The latter can cause a frame shift, changed amino acid composition, and a formation of truncated in the protein. None of the detected mutations were found in the control sample of ophthalmologically examined individuals without PCG (100 people). Variants R444* (rs377049098) and R444Q (rs72549376) were not found in the general population sample either (576 randomly selected West Siberia residents). All the detected mutations caused the development of the autosomal recessive form of primary congenital glaucoma. The most severe clinical phenotype was observed in carriers of mutations in codon 444 of the gene. Consequently, in children with signs of increased intraocular pressure, molecular genetic analysis of the CYP1B1 gene is advisable for early diagnosis and timely initiation of PCG therapy.

P0517RENAL STEM CELLS (ARPCS) AS A NEPHROPROTECTIVE APPROACH DURING CISPLATIN-INDUCED ACUTE KIDNEY INJURY: A DEFENSE MECHANISM BY EXTRACELLULAR VESICLES CARRYING THE CYP1B1 GENE

Background and Aims Cisplatin, is a nonspecific cytotoxic agent that primarily interferes with cellular DNA replication and the cell cycle, nevertheless it lacks tumor selectivity and acts also in normal cells. The most serious adverse reaction of cisplatin is Acute Kidney Injury (AKI), limiting its use and efficacy in chemotherapy. Cisplatin nephrotoxicity is observed in more than 30% of older patients, however the mechanism of nephrotoxicity remains unclear and specific preventive measures are not available. Today, there is an urgent need for specific nephroprotective strategies to be used during cisplatin chemotherapy. Recently, we found that tubular stem/progenitor cells (tARPC) are able to protect the tubular epithelial (RPTEC) from cisplatin induced injury, preserving their proliferation and inhibiting apoptosis. The aim of this study was to identify the molecular mechanisms involved in tARPC-mediated resistance to cisplatin. Method Co-cultures of RPTEC cells and tARPCs were exposed to cisplatin (2.5 µM) for 6 h and then kept in culture for 96 h. Gene expression profile was obtained from tARPCs and RPTECs by Agilent SurePrint G3 Human Gene Expression Microarrays. Genespring and R software were used for the analysis. Gene expression data were validated by Real-time PCR. Extracellular vesicles were isolated from cell culture supernatant by miRCURY Exosome Cell/Urine/CSF Kit (Qiagen) and RNA contained in extracellular vesicles was purified, analyzed in quality by Bioanalyzer (RNA nano) and evaluated by qPCR. The BrdU assay and caspase 3 were used to measure proliferation and apoptosis levels. Immunohistochemical expression of activated caspase-3 was used as a marker of apoptosis in RPTECs. Results By a whole-genome gene expression analysis, we found 107 genes specifically modulated by RPTECs in response to cisplatin and, among these, 30 genes induced by ARPCs following the cisplatin damage. In particular, we found a strong upregulation of the CYP1B1 gene (false discovery rate corrected p value <0.05; fold change=4,1). The qPCR confirmed the increase in CYP1B1 levels in the co-cultures with respect to the respective basal conditions (p <0.05). Interestingly, the CYP1B1 mRNA was also enveloped in Extracellular Vesicles released in the cell co-culture media by tARPC and RPTEC after cisplatin exposition. The CYP1B1 gene encodes a member of the cytochrome P450 superfamily of enzymes and the produced enzyme metabolizes procarcinogens, such as polycyclic aromatic hydrocarbons. CYP1B1 has been shown to be active within tumors and is also capable of metabolizing a structurally diverse range of anticancer drugs. It is responsible for the resistance to docetaxel, cisplatin, tamoxifen and nucleoside analogues. CYP1B1 is involved in the detoxification of the body by various exogenous toxic agents, including cisplatin. We found that CYP1B1 gene was expressed at low levels in RPTECs and in cisplatin-damaged RPTECs. Moreover, 96 h days after 2.5 μM exposure to cisplatin, RPTECs reduced the proliferation and underwent in apoptosis, as showed by caspase 3. However, in co-culture with ARPCs, ARPC cellular and extracellular vesicles CYP1B1 gene expression significantly increased, the apoptotic process was stopped and RPTECs increased their proliferation rate. These data support the hypothesis that ARPCs are sensor of cisplatin damaged-RPTEC and confers cisplatin resistance by transferring CYP1B1 gene in extracellular vesicles. Conclusion This is the first evidence of a cisplatin-induced overexpression of CYP1b1 in renal epithelial cells as a defense mechanism against cisplatin toxicity. This is consistent with our previous data showing that renal progenitors are resistant to cisplatin. The findings may have biological and clinical significance in terms of their implications in cellular communications and potential use of CYP1B1 as biomarkers for AKI induced by cisplatin or as protective agent.

Cytochrome P450 Family 1 B1 Gene Mutations in Primary Congenital Glaucoma Affected Egyptian Patients

Aims: Primary congenital glaucoma (PCG) is a leading cause of childhood blindness. The cytochrome P450 family 1, subfamily B, polypeptide 1 (CYP1B1) is the most mutated gene that is associated with PCG. Very few studies have examined the promoter region and exon1 of the CYP1B1 gene. This work was planned to contribute to the description of the possible causative mutations of CYP1B1 gene that are related to PCG affected Egyptian patients. Patients and Methods: Patients diagnosed as glaucomatous based on their symptoms and detailed ophthalmological examinations at the time of presentation underwent an intraocular pressure lowering surgical procedure. Investigations were further proceeded on the molecular level. Sequencing-based mutation screen for the promoter region, exon1 and the coding region of exon3 of CYP1B1 gene have been performed in two related consanguineous PCG affected families and four other sporadic Egyptian patients using the polymerase chain reaction (PCR) assay; where PCR products were sequenced, and further analyzed. Results: Sequencing analysis revealed three novel mutations in PCG affected patients one in the promoter region (g.G2872A) and two in exon1 (g.C3268T and g.C3332T). Two additional mutations in exon3 (p.L432V and p.N453S) reported for the first time in PCG affected Egyptian patients. Clinical and genetic data of the two consanguineous families revealed that although the four parents have the same variations as their sons, they are ophthalmologically free. Conclusion: Regular ophthalmic examinations of siblings and parents of these affected patients should take place for early detection of any form of glaucoma to allow prompt diagnosis and early treatment when needed. Clinical examination and molecular genetic data could contribute to early diagnosis and prevention of the visual impairment caused by PCG. This study provides groundwork for expanded genetic investigations in Egypt paving the way for genetic counseling to help affected families make informed medical and personal decisions.

Polymorphisms in Phase I (CYP450) Genes CYP1A1 (rs4646421), CYP1B1 (rs1056836), CYP19A1 (rs749292) and CYP2C8 (rs1058930) and Their Relation to Risk of Breast Cancer: A Case-Control Study in Mazandaran Province in North of Iran

BACKGROUND: The second leading cause of cancer-related death in women is breast cancer. Xenobiotic Metabolizing Enzymes (XMEs) contribute to the detoxification of numerous cancer therapy-induced products. In the metabolism of xenobiotic, cytochrome P450s or monooxygenases perform an important function by catalysing the hydroxylation reaction. In this study, the susceptibility and genetic polymorphisms of CYP450 isoenzymes was investigated that may have an etiological role in breast cancer. AIM: The main purpose of this study was to evaluate the association of CYP1A1 (rs4646421), CYP1B1 (rs1056836), CYP2C8 (rs1058930), and CYP19A1 (rs749292) polymorphisms with the risk of breast cancer in Mazandaran province. MATERIAL AND METHODS: This cross-sectional case-control study were recruited 72 patients and 51 healthy individuals and was performed between March 2018 to May 2018 in the Oncology Department at Imam Hospital in Sari city, Iran. Peripheral blood samples were collected in EDTA tube, and DNA extraction was performed using the salting-out method and WizPrep extraction kits. Breast cancer patients with known clinicopathological characters and healthy women as control group were genotyped for genes polymorphisms by PCR-RFLP technique, using restriction enzymes. Chi-square, Fisher exact test and Logistic regression model, were applied for statistical analysis. RESULTS: The results of the experiments showed that there was a significant relationship between two groups and the age of the patients is significantly higher than the control group (p = 0.044). According to the chi-square and Fisher exact test, education, pregnancy, menopause status and oppose were significant between the two groups. Based on using a logistic regression model in two normalized and age-adjusted models to finding relationship between the genotypes of each gene and breast cancer risk, it was determined that in the CYP2C8 genotype, those who have the CG allele have a 7.74 degree increased risk of breast cancer (CI = 95% 0.95-62.5) and in the CYP19A1 gene, individuals with GA genotype, increased risk of breast cancer (CI = %95 1.52-27.21), about the CYP1B1 gene, people with two genotypes of CG + GG had higher risk of breast cancer (CI = %95 1.19-5.71) and allele G has decreased risk of breast cancer in this gene (P = 0.0271), also allele G in CYP2C8 gene had the protective effect (P = 0.02). In the age-adjusted model, for the CYP2C8 gene, GG genotype increased risk of breast cancer (CI = %95 1.11-75.84) as well as, the CG + GG genotype in CYP1B1 gene (CI = %95 1.31-6.57). CONCLUSION: Our results confirm the association between CYP2C8 (rs1058930), CYP19A1 (rs749292) and CYP1B1 (rs1056836) gene polymorphisms and increased risk of breast cancer in women in Mazandaran province.