ABERRANT METHYLATION OF CANCER-RELATED GENES IN VIETNAMESE BREAST CANCER PATIENTS: ASSOCIATIONS WITH CLINICOPATHOLOGICAL FEATURES

BACKGROUND

Epigenetic alteration is one of the most common molecular changes identified in the progression of breast cancer (BC).

AIM

To study the frequency and relation between methylation of BRCA1, MLH1, MGMT, GSTP1, APC, RASSF1A, p16, WIF, and EGFR and the clinicopathological features in Vietnamese BC patients.

MATERIALS AND METHODS

Methylation-specific polymerase chain reaction (MS-PCR) and SPSS 20.0 software were utilized in order to identify methylated frequency as well as evaluate its relationship with the patient's clinical features.

RESULTS

In 162 BC cases, the methylation rates of the selected genes were 53.7%, 22.8%, 38.9%, 34.6%, 29.0%, 46.3%, 20.4%, 18.5%, and 28.4% respectively. In 32 cases of benign breast diseases (BBD) - 12.5%, 15.6%, 6.3%, 3.1%, 12.5%, 21.9%, 3.1%, 15.6% and 3.1%. BC samples displayed higher BRCA1, MGMT, GSTP1, APC, RASSF1A, WIF1, and p16 methylation levels than BBD samples (p < 0.001). Hypermethylation of BRCA1, GSTP1, and RASSF1A was predominant in the invasive ductal carcinoma, while hypermethylation of BRCA1, GSTP1, RASSF1A, WIF-1, and p16 was found to significantly correlate with lymph node metastasis (p < 0.05). Hypermethylation of BRCA1, MGMT, and GSTP1 was more common in stage III (p < 0.05) than in stages I/II, whereas MLH1 methylation was predominant in stage I and APC methylation was less common in stage III (p = 0.03). In addition, methylation of RASSF1A and EGFR was more frequent in younger patients (p < 0.01) than in elder patients.

CONCLUSION

These data suggest that a gene panel (BRCA1/MGMT/GSTP1) can be used to support the diagnosis and screening of Vietnamese patients' BC with a sensitivity of 70%, and a specificity of 85%.

Polymorphism of glutathione S-transferase P1 of dogs with mammary tumours

Mammary tumours constitute more than half of neoplasms in female dogs from different countries. Genome sequences are associated with cancer susceptibility but there is little information available about genetic polymorphisms of glutathione S-transferase P1 (GSTP1) in canine cancers. The aim of this study was to find single nucleotide polymorphisms (SNPs) in GSTP1 of dogs (Canis lupus familiaris) with mammary tumours compared to healthy dogs and to determine the association between GSTP1 polymorphisms and the occurrence of these tumours. The study population included 36 client-owned female dogs with mammary tumours and 12 healthy female dogs, with no previous diagnosis of cancer. DNA was extracted from blood and amplified by PCR assay. PCR-products were sequenced by Sanger method and analysed manually. The 33 polymorphisms were found in GSTP1: 1 coding SNP (exon 4), 24 non-coding SNPs (9 in exon 1), 7 deletions and 1 insertion. The 17 polymorphisms have been found in introns 1, 4, 5 and 6. The dogs with mammary tumours have significant difference from healthy in SNPs I4 c.1018 + 123 T > C (OR 13.412, 95%CI 1.574-114.267, P = .001), I5 c.1487 + 27 T > C (OR 10.737, 95%CI 1.260-91.477, P = .004), I5 c.1487 + 842 G > C (OR 4.714, 95% CI 1.086-20.472, P = .046) and I6 c.2481 + 50 A > G (OR 12.000, 95% CI 1.409-102.207, P = .002). SNP E5 c.1487 T > C and I5 c.1487 + 829 delG also differed significantly (P = .03) but not to the confidence interval. The study, for the first time, showed a positive association of SNPs in GSTP1 with mammary tumours of dogs, that can possibly be used to predict the occurrence of this pathology.

Association of glutathione thioltransferase P1 (GSTP1) gene polymorphism with sensitivity to oxaliplatin and traditional Chinese medicine syndrome types in colon cancer patients

BACKGROUND

Colon cancer has a high incidence, and chemotherapy is still the only treatment for it. Oxaliplatin, as a third generation platinum chemotherapy drug, has a good efficacy in the treatment of colorectal cancer. However, due to the influence of genetic susceptibility, people with different genotypes have different sensitivities to oxaliplatin. As a result, the therapeutic effect varies greatly among different patients.

AIM

To explore the association of glutathione sulfhydryl transferase P1 (GSTP1) gene polymorphism with sensitivity to oxaliplatin and traditional Chinese medicine (TCM) syndrome types in colon cancer patients.

METHODS

A total of 246 colon cancer patients who received chemotherapy with oxaliplatin-based regimens at our hospital from January 2015 to June 2020 were selected. The Ile105Val polymorphism of GSTP1 gene was detected before chemotherapy, and the curative effect was evaluated after three cycles of chemotherapy. The clinical data and the distribution of GSTP1 genotypes of patients with different chemotherapy effects were compared, and the factors affecting the efficacy of oxaliplatin chemotherapy were analyzed. The distribution of TCM syndrome types of colon cancer patients was also calculated, and the relationship between GSTP1 genotype and TCM syndrome types and syndrome elements was evaluated.

RESULTS

There was a polymorphism in the Ile105Val locus of the GSTP1 gene, which conformed to the Hardy-Weinberg equilibrium law and was representative of the population (P > 0.05). After three cycles of oxaliplatin chemotherapy in 246 patients with colon cancer, the total effective rate was 43.90% (108/246). Clinical stage Ⅳ, moderate/well differentiation lymph node metastasis, and GSTP1 genotypes AG and GG were important factors influencing the effect of oxaliplatin chemotherapy in colon cancer patients (P < 0.05). The distribution of TCM syndromes in 118 patients with colon cancer was as follows: Stasis-toxin internal resistance type > Spleen and kidney Yang deficiency type > Qi and blood deficiency type > Damp-heat accumulation type > Liver and kidney Yin deficiency type. There was a statistically significant difference in the distribution of GSTP1 genotypes in patients with blood stasis internal resistance type and Qi and blood deficiency type (P < 0.05). There was a statistically significant difference in the distribution of TCM syndrome types among patients with different GSTP1 genotypes (P < 0.05). The distribution of spleen, lung, and kidney elements of TCM syndromes in patients with different GSTP1 genotypes was significantly different (P < 0.05).

CONCLUSION

There is an association between the GSTP1 gene polymorphism and sensitivity to oxaliplatin and TCM syndrome types in colon cancer patients. Therefore, the detection of GSTP1 gene polymorphism is helpful to evaluate the therapeutic effect in patients receiving oxaliplatin as the basic drug chemotherapy, determine the type of TCM syndrome, and provide scientific guidance for individualized treatment of colon cancer.

Glutathione S transferase T1 gene polymorphism and its promoter methylation are associated with breast cancer susceptibility in Egyptian women

BACKGROUND

Breast cancer (BC) is one of the leading causes of cancer mortality in women. Glutathione S-transferase (GSTT1) is involved in activation of detoxification reactions and catalysis of chemicals conjugation with glutathione. GSTT1 genotype is a limiting factor for some environmental diseases. Epigenetic changes have an essential role in BC through inappropriate interaction between genomic and environmental risk factors.

AIM

This study was directed to explore the association of BC risk with GSTT1 genetic variations and its methylation status in Egyptian women.

DESIGN AND METHODS

This study included 100 healthy women as the control group and 100 patients were clinically and histologically diagnosed with breast cancer. All blood samples were used for genomic DNA extraction. GSTT1 genotyping was accomplished by multiplex PCR and methylation-specific PCR was used to analyze the GSTT1 promoter methylation status.

RESULTS

Breast cancer patients showed significant incidence of null GSTT1 in relation to controls (p = 0.004). GSTT1 gene promoter methylation status showed significant difference between hypermethylated and unmethylated patients when compared with healthy subjects (p = 0.005). GSTT1 promoter methylation status was not significantly associated with null genotype. There was no significant association between GSTT1-null genotypes and BC stage in cases with or without family history, but for promotor methylation, there was significant association with stage III and IV breast cancer disease.

CONCLUSION

GSTT1 null genetic variant and promoter hypermethylation in the GSTT region of the gene may be considered as critical risk factors for BC in Egyptian women.

Silencing of long non-coding RNA LINC01270 inhibits esophageal cancer progression and enhances chemosensitivity to 5-fluorouracil by mediating GSTP1methylation

Esophageal cancer (EC) is a serious digestive malignancy which remains the sixth leading cause of cancer-related deaths worldwide. Emerging evidence suggests the involvement of long non-coding RNAs (lncRNAs) in the tumorigenesis of EC and thus, in this study we explored the potential effects of lncRNA LINC01270 on EC cell proliferation, migration, invasion and, drug resistance via regulation of glutathione S-transferase P1 (GSTP1) methylation. First, we screened out the EC-related differentially expressed lncRNAs, and the expression of our top candidate LINC01270 was quantified in EC tissues and cells. To define the role of LINC01270 in EC progression, we evaluated the proliferation, migration and invasion of EC cells when the LINC01270 was overexpressed or knocked down, in the presence of the GSTP1 methylation inhibitor SGI-1027 and 5-fluorouracil (5-FU). In addition, interaction between LINC01270 and methylation of the GSTP1 promoter was identified. Finally, we assessed transplantable tumor growth in nude mice. LINC01270 was up-regulated and GSTP1 was down-regulated in EC tissues and cells. Silencing of LINC01270 inhibited migration and invasion, and enhanced the sensitivity of 5-FU in EC cells. We found that LINC01270 recruited the DNA methyltransferases DNMT1, DNMT3A and DNMT3B initiating GSTP1 promoter methylation, thereby leading to the proliferation, migration, invasion and drug resistance of EC cells. Moreover, GSTP1 overexpression was observed to reverse the effects of LINC01270 overexpression on EC cells and their response to 5-FU. Taken together, this study shows that inhibition of LINC01270 can lead to suppression of EC progression via demethylation of GSTP1, highlighting this lncRNA as a potential target for EC treatment.

Genetic and epigenetic modifications of adiponectin gene: Potential association with breast cancer risk

BACKGROUND

Adipokines produced by adipose tissue are directly linked to obesity and may contribute to the pathogenesis of cancer. We hypothesized that genetic and epigenetic modifications in the adiponectin (ADIPOQ) gene and their impact on serum ADIPOQ levels may participate in increasing breast cancer (BC) risk. The present study aimed to investigate ADIPOQ +45 T/G gene polymorphism, methylation status at CpG sites -74 nucleotides (nt) and -283 nt of the ADIPOQ gene, and ADIPOQ serum levels in BC obese women.

METHODS

Serum ADIPOQ was measured by an enzyme-linked immunosorbent assay. ADIPOQ +45 T/G gene polymorphism and ADIPOQ promoter methylation status were determined using a polymerase chain reaction (PCR) and a methylation-specific PCR, respectively, in 120 obese women with BC and 120 age-matched controls.

RESULTS

ADIPOQ +45 GG genotype carriers had a significant increased risk of developing BC (odds ratio = 6.2, 95% confidence interval = 1.3-29.6, p = 0.02). ADIPOQ gene methylation at site -74 nt resulted in a 1.7-fold increased BC risk. Methylation at site -283 nt resulted in a 1.9-fold increased BC risk. Moreover serum levels of ADIPOQ were significantly decreased in BC patients and down-regulated in the presence of methylation in both examined sites. By contrast, no association between ADIPOQ gene polymorphism and serum ADIPOQ level was detected. Using both methylated sites in one panel detected cancer breast with 76.67% sensitivity and 62.18% accuracy.

CONCLUSIONS

ADIPOQ +45 T/G polymorphism and ADIPOQ promoter methylation were found to be associated with BC risk in obese Egyptian women.

Methylation of Glutathione-S-Transferase P1 Promotor in Egyptian Females with Breast Cancer

Background:

Breast cancer (BC) is the second most common cancer after the lung cancer worldwide and number one killing cancer in Egyptian females . It is a multifactorial disease driven by different environmental, hormonal, genetic and epigenetic factors. Epigenetic alterations have been studied in cancer breast. Role of GSTP1 promotor methylation in breast cancer has been studied in different ethnic groups.

Objectives:

Current study aimed at studying the methylation status of the promotor region of glutathione-S-transferase P1 in breast ductal carcinoma of a cohort group of Egyptian females and its correlations with histopathological and prognostic parameters.

Methods:

Control group included 15 fresh normal breast tissues taken from BC female patients after leaving a clearly defined safety margin and a Patient group included confirmed 35 fresh breast ductal carcinoma tissue biopsies taken from female patients postoperatively. To all patients clinical examination, radiological examination (plain X-ray chest and or CT scan, ultrasonography of abdomen and pelvis were done), in addition to histopathological examination, typing, grading and staging of tumour, hormonal receptors status and molecular typing of breast mass. GSTP1 methylation status was evaluated using methyl specific polymerase chain reaction.

Results:

Statistical significant increase was found in methylation status of GSTP1 promotor gene in BC cases than that in control group, (60% of patients samples had methylated GSTP1 promotor vs only 6.7% of controls) (p= >0.001). No association was found between GSTP1 promotor methylation status and the poor prognostic factors neither with hormonal profile nor molecular type. However, GSTP1 promotor methylation were two times higher in postmenopausal than premenopausal cases and three times higher in late grade (III). Also GSTP1 promotor methylation was 2.4 times higher in Her2 positive cases than either ER or PR positive cases. Conclusion: Glutathione-S-Transferase P1 Promotor methylation plays a role in breast cancer development.

Glutathione S-transferase π: a potential role in antitumor therapy

Glutathione S-transferase π (GSTπ) is a Phase II metabolic enzyme that is an important facilitator of cellular detoxification. Traditional dogma asserts that GSTπ functions to catalyze glutathione (GSH)-substrate conjunction to preserve the macromolecule upon exposure to oxidative stress, thus defending cells against various toxic compounds. Over the past 20 years, abnormal GSTπ expression has been linked to the occurrence of tumor resistance to chemotherapy drugs, demonstrating that this enzyme possesses functions beyond metabolism. This revelation reveals exciting possibilities in the realm of drug discovery, as GSTπ inhibitors and its prodrugs offer a feasible strategy in designing anticancer drugs with the primary purpose of reversing tumor resistance. In connection with the authors' current research, we provide a review on the biological function of GSTπ and current developments in GSTπ-targeting drugs, as well as the prospects of future strategies.

Methylation Profiles of BRCA1, RASSF1A and GSTP1 in Vietnamese Women with Breast Cancer

Objective: This study investigated the DNA promoter methylation profiles of BRCA1, RASSF1A and GSTP1 genes, both individually and in an integrative manner in order to clarify their correlation with clinicopathological parameters of breast cancer from Vietnamese patients, and establish new potential integrative methylation biomarkers for breast cancer detection. Material and methods: The methylation frequencies of BRCA1, RASSF1A and GSTP1 were analyzed by methylation specific polymerase chain reaction (MSP) in 70 specimens of breast carcinomas and 79 pairs of tumor and matched adjacent normal tissues from breast cancer patients. Results: All the three analyzed genes showed a concordance concerning their promoter methylation in tumor and adjacent normal tissue. The methylation of BRCA1, RASSF1A and GSTP1 was found in 58.23 %, 74.68 % and 59.49 % of tumor tissues and 51.90 %, 63.29 % and 35.44 % of corresponding adjacent tissues, respectively. When each gene was assessed individually, only the methylation of GSTP1 was significantly associated with tumor tissues (p=0.003). However, the methylation frequency of at least one of the three genes and the methylation frequency of all the three genes both showed significant association with tumor (p=0.008 and p=0.04, respectively). The methylation of BRCA1 was found to be significantly associated with tumor grade (p=0.01). Conclusion: This study emphasized that the panel of the three genes BRCA1, RASSF1A and GSTP1 can be further developed as potential biomarkers in diagnosis and classification of breast cancer in Vietnamese women.