scholarly journals GLAD-PCR assay of DNA methylation sites in regulatory regions of some tumor-suppressor genes in breast cancer

2022 ◽  
Vol 20 (6) ◽  
pp. 41-54
Author(s):  
N. A. Smetannikova ◽  
M. A. Abdurashitov ◽  
A. G. Akishev ◽  
P. I. Pozdnyakov ◽  
E. V. Dubinin ◽  
...  

Hypermethylation of the RcgY sites is shown for many cancer diseases. such aberrant methylation, suppressing the gene activity, occurs at early stages of carcinogenesis. Recently, using glad-pcR assay, we have detected aberrantly methylated RcgY sites, which can be considered to be epigenetic markers of colorectal, lung, and gastric cancers. in breast cancer, methylation of the regulatory regions of ALX4, BMP2, CCND2, CDH13, CDX1, FOXA1, GALR1, GATA5, GREM1, HIC1, HMX2, HS3ST2, HOXC10, ICAM5, LAMA1, RARB, RASSF1A, RUNX3, RXRG, RYR2, SFRP2, SOX17, TERT, and ZNF613 tumor-suppressor genes is reported. in the present work, we determined aberrantly methylated RcgY sites in the regulatory regions of these genes in dNa preparations from breast cancer tissues. the study of dNa samples from 30 tumor and 22 normal mammary tissue samples demonstrates a high diagnostic potential of selected R(5mc)gY sites in regulatory regions of CCND2, BMP2, GALR1, SOX17, HMX2, and HS3ST2 genes with total index of sensitivity and specificity for R(5mc)gY detection in tumor dNa 90.0 % and 100.0 %, respectively.

Acta Naturae ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 124-133
Author(s):  
Boris S. Malyshev ◽  
Nina A. Netesova ◽  
Natalia A. Smetannikova ◽  
Murat A. Abdurashitov ◽  
Alexander G. Akishev ◽  
...  

At early stages of carcinogenesis, the regulatory regions of some tumor suppressor genes become aberrantly methylated at RCGY sites, which are substrates of DNA methyltransferase Dnmt3. Identification of aberrantly methylated sites in tumor DNA is considered to be the first step in the development of epigenetic PCR test systems for early diagnosis of cancer. Recently, we have developed a GLAD-PCR assay, a method for detecting the R(5mC)GY site in the genome position of interest even at significant excess of DNA molecules with a non-methylated RCGY site in this location. The aim of the present work is to use the GLAD-PCR assay to detect the aberrantly methylated R(5mC)GY sites in the regulatory regions of tumor suppressor genes (brinp1, bves, cacna2d3, cdh11, cpeb1, epha7, fgf2, galr1, gata4, hopx, hs3st2, irx1, lrrc3b, pcdh10, rprm, runx3, sfrp2, sox17, tcf21, tfpi2, wnt5a, zfp82, and znf331) in DNA samples obtained from gastric cancer (GC) tissues. The study of the DNA samples derived from 29 tumor and 25 normal gastric tissue samples demonstrated a high diagnostic potential of the selected RCGY sites in the regulatory regions of the irx1, cacna2d3, and epha7 genes; the total indices of sensitivity and specificity for GC detection being 96.6% and 100%, respectively.


2021 ◽  
Author(s):  
Dejuan Yang ◽  
Yue Wu ◽  
Qin Xiang ◽  
Dishu Zhou ◽  
Zhu Qiu ◽  
...  

Abstract Background: Aberrant methylation of tumor suppressor genes is a common feature of breast cancer. Identifying a panel of methylated genes that are sensitive and specific for breast cancer could help to diagnose and predict prognosis of breast cancer.Methods: We determined the methylation status of DACT1, PAX5, PLCD1, ZNF545 and TET1 in 32 benign controls, 237 cancer tissue samples and 33 paired plasma samples.Results: PAX5 and PLCD1 showed exceedingly high methylation rates with percentages of 69.2% and 54.9%, whereas the methylation percentage of DACT1, ZNF545 and TET1 were 33.8%, 28.7% and 18.2% in cancer samples, respectively. A better survival of patients with ZNF545 methylation (p = 0.0350) was detected. Correlation of promoter methylation and clinicopathological features in 32 individuals with benign disease and 237 cancer patients demonstrated that methylated status of DACT1 (p=0.012), PLCD1 (p=0.013), and ZNF545 (p=0.012) had significant difference in age, and the methylation of PAX5 (p=0.006) was correlated with absence of hormone receptors, which implied an adverse outcome. PAX5 and PLCD1 both had high sensitivity (69.20% and 54.85%, respectively) and high specificity (87.50% and 100.00%, respectively). Patients with methylation of PAX5 likely to have a higher risk of breast cancer (OR=15.726, 95% CI=5.323-46.463, p<0.001), and statistical analysis of public online database showed the similar results. Conclusion: PAX5, PLCD1, ZNF545 and TET1 may serve as new potential diagnostic and prognostic biomarkers for breast cancer.


Author(s):  
Abhijit Chakraborty ◽  
Atul Katarkar ◽  
Keya Chaudhuri ◽  
Ashis Mukhopadhyay ◽  
Jayasri Basak

AbstractHereditary breast cancer constitutes 5–10% of all breast cancer cases. Inherited mutations in the BRCA1 and BRCA2 tumor-suppressor genes account for the majority of hereditary breast cancer cases. The BRCA1 C-terminal region (BRCT) has a functional duplicated globular domain, which helps with DNA damage repair and cell cycle checkpoint protein control. More than 100 distinct BRCA1 missense variants with structural and functional effects have been documented within the BRCT domain. Interpreting the results of mutation screening of tumor-suppressor genes that can have high-risk susceptibility mutations is increasingly important in clinical practice. This study includes a novel mutation, p.His1746 Pro (c.5237A>C), which was found in BRCA1 exon 20 of a breast cancer patient. In silico analysis suggests that this mutation could alter the stability and orientation of the BRCT domain and the differential binding of the BACH1 substrate.


Tumor Biology ◽  
2017 ◽  
Vol 39 (2) ◽  
pp. 101042831769225 ◽  
Author(s):  
Umesh Kumar ◽  
Ujjawal Sharma ◽  
Garima Rathi

One of the mechanisms for epigenetic silencing of tumor suppressor genes is hypermethylation of cytosine residue at CpG islands at their promoter region that contributes to malignant progression of tumor. Therefore, activation of tumor suppressor genes that have been silenced by promoter methylation is considered to be very attractive molecular target for cancer therapy. Epigenetic silencing of glutathione S-transferase pi 1, a tumor suppressor gene, is involved in various types of cancers including breast cancer. Epigenetic silencing of tumor suppressor genes can be reversed by several molecules including natural compounds such as polyphenols that can act as a hypomethylating agent. Curcumin has been found to specifically target various tumor suppressor genes and alter their expression. To check the effect of curcumin on the methylation pattern of glutathione S-transferase pi 1 gene in MCF-7 breast cancer cell line in dose-dependent manner. To check the reversal of methylation pattern of hypermethylated glutathione S-transferase pi 1, MCF-7 breast cancer cell line was treated with different concentrations of curcumin for different time periods. DNA and proteins of treated and untreated cell lines were isolated, and methylation status of the promoter region of glutathione S-transferase pi 1 was analyzed using methylation-specific polymerase chain reaction assay, and expression of this gene was analyzed by immunoblotting using specific antibodies against glutathione S-transferase pi 1. A very low and a nontoxic concentration (10 µM) of curcumin treatment was able to reverse the hypermethylation and led to reactivation of glutathione S-transferase pi 1 protein expression in MCF-7 cells after 72 h of treatment, although the IC50 value of curcumin was found to be at 20 µM. However, curcumin less than 3 µM of curcumin could not alter the promoter methylation pattern of glutathione S-transferase pi 1. Treatment of breast cancer MCF-7 cells with curcumin causes complete reversal of glutathione S-transferase pi 1 promoter hypermethylation and leads to re-expression of glutathione S-transferase pi 1, suggesting it to be an excellent nontoxic hypomethylating agent.


2019 ◽  
Vol 20 (16) ◽  
pp. 1151-1157 ◽  
Author(s):  
Jia Yu ◽  
Jacqueline Zayas ◽  
Bo Qin ◽  
Liewei Wang

Triple-negative breast cancer (TNBC) accounts for 15–20% of all invasive breast cancers and tends to have aggressive histological features and poor clinical outcomes. Unlike, estrogen receptor- or HER2-positive diseases, TNBC patients currently lack the US FDA-approved targeted therapies. DNA methylation is a critical mechanism of epigenetic modification. It is well known that aberrant DNA methylation contributes to the malignant transformation of cells by silencing critical tumor suppressor genes. DNA methyltransferase inhibitors reactivate silenced tumor suppressor genes and result in tumor growth arrest, with therapeutic effects observed in patients with hematologic malignancies. The antitumor effect of these DNA methyltransferase inhibitors has also been explored in solid tumors, especially in TNBC that currently lacks targeted therapies.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2780-2780
Author(s):  
Ana Valencia ◽  
Jose Cervera ◽  
Esperanza Such ◽  
Esther Gamero ◽  
Mariam Ibañez ◽  
...  

Abstract Abstract 2780 Poster Board II-756 Patients with refractory anemia with ring sideroblasts (RARS) are considered to have good prognosis and anemia is usually managed with best supportive care and erythroid stimulating agents. Nowadays, no specific molecular marker related to outcome and disease progression has been identified. Several genes involved in cell cycle and apoptosis that may become inactivated by aberrant hypermethylation have been identified in patients with myelodysplastic syndromes (MDS) but the significance of a methylation profile (studying several genes at the same time) in RARS is unknown, mainly because the number of patients with RARS in published reports is rather low. To assess the implication of aberrant methylation in RARS, we studied the methylation status of 25 sequences of a set of tumor suppressor genes in 40 patients (median age 70 yr, 25 male gender) with RARS according to FAB criteria [WHO classification, RARS in 22 patients (55%); refractory citopenia with multilineage dysplasia and ring sideroblasts, 18 (45%)] by means of methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay. The MS-MLPA procedure (SALSA MLPA kit ME001, MRC-Holland, Amsterdam, The Netherlands) has been developed for detecting in a semi-quantitative manner changes in the methylation status of 25 tumor suppressor genes in a single experiment. Briefly, approximately 50 ng of DNA were denatured and hybridized with MLPA probes. Subsequently, the probes were ligated in half of every sample, whereas for the rest of the sample, ligation was combined with an endonuclease HhaI digestion resulting in ligation of the methylated sequences only. PCR was performed as described by the manufacturer, and then separated by capillary gel electrophoresis and quantified using the Genemapper software (ABI 310, Applied Biosystems, Foster City, CA). Quantification of the methylation status was done by dividing the peak area with the combined areas of the control probes lacking the target sequence of the HhaI. Finally, the relative peak area of each target probe from the digested sample was compared with those obtained from the undigested sample. Aberrant methylation was scored when the calculated methylation percentage was >10%. To validate the MS-MLPA method the methylation status of CDKN2B was also analyzed by methylation-specific PCR (MSP). Actuarial curves of OS were built by Kaplan-Meier method and differences between curves compared with log-rank tests. Small numbers precluded the use of multivariate methodology. The MS-MLPA analysis detected methylation of at least one gene in 17 patients (42.5%). The genes aberrantly methylated were CDKN2B (n = 8, 20%), RASSF1 (n = 7, 17%), RARB (n = 3, 7.5%), CDH13 (n = 3, 7.5%) and FHIT (n = 2; 5%). Of the 17 patients, five (12%) presented methylation in two genes (RASSF1-FHIT in 2, RASSF1-RARB in 1, RASSF1-CDH13 in 1, and CDKN2B-CDH13 in 1, who was the only patient who progressed to AML). The presence of aberrant gene methylation was not significantly associated with any clinical or biological characteristic or WHO morphological subtype. Patients with aberrant gene methylation had a significantly shorter overall survival (OS) than patients without methylated genes (median OS, 72 mo vs 114 mo, respectively; P = 0.03). Patients with hemoglobin level below 10 g/dL and platelet count below 150 ×109/L also had a significantly poorer OS (P= 0.01 and P= 0.02, respectively). As the majority of probes used in the MS-MPLA method detect methylation in only one CpG pair, the results of CDKN2B methylation were validated by MSP, which yielded the same methylation results than with MS-MPLA methodology. The 8 patients with methylated CDKN2B show a trend for a shorter survival than the remaining 32 with unmethylated CDKN2B (median 72 mo vs 114 mo, P = 0.08). The results of this study indicate that aberrant methylation of several tumor suppressor genes is observed in a substantial proportion of patients with RARS. As occurs in patients with high-risk MDS, our results suggest that aberrant gene methylation confers a poor prognosis in RARS, but these data and their potential independent value require confirmation in larger series that employ multivariate methods. Finally, these findings provide a strong rationale for the use of hypomethylating agents (e.g., azacitidine or decitabine) in patients with RARS. This work has been partially supported by ISCIII grants RD06/0020/0031 and CA08/00141. Disclosures: No relevant conflicts of interest to declare.


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