Multiplexed DNA Methylation Analysis in Colorectal Cancer Using Liquid Biopsy and Its Diagnostic and Predictive Value

Early diagnosis of colorectal cancer (CRC) is of high importance as prognosis depends on tumour stage at the time of diagnosis. Detection of tumour-specific DNA methylation marks in cfDNA has several advantages over other approaches and has great potential for solving diagnostic needs. We report here the identification of DNA methylation biomarkers for CRC and give insights in our methylation-sensitive restriction enzyme coupled qPCR (MSRE-qPCR) system. Targeted microarrays were used to investigate the DNA methylation status of 360 cancer-associated genes. Validation was done by qPCR-based approaches. A focus was on investigating marker performance in cfDNA from 88 patients (44 CRC, 44 controls). Finally, the workflow was scaled-up to perform 180plex analysis on 110 cfDNA samples, to identify a DNA methylation signature for advanced colonic adenomas (AA). A DNA methylation signature (n = 44) was deduced from microarray experiments and confirmed by quantitative methylation-specific PCR (qMSP) and by MSRE-qPCR, providing for six genes’ single areas under the curve (AUC) values of >0.85 (WT1, PENK, SPARC, GDNF, TMEFF2, DCC). A subset of the signatures can be used for patient stratification and therapy monitoring for progressed CRC with liver metastasis using cfDNA. Furthermore, we identified a 35-plex classifier for the identification of AAs with an AUC of 0.80.

DNA methylation landscape of 16 canine somatic tissues by methylation-sensitive restriction enzyme-based next generation sequencing

DNA methylation plays important functions in gene expression regulation that is involved in individual development and various diseases. DNA methylation has been well studied in human and model organisms, but only limited data exist in companion animals like dog. Using methylation-sensitive restriction enzyme-based next generation sequencing (Canine DREAM), we obtained canine DNA methylation maps of 16 somatic tissues from two dogs. In total, we evaluated 130,861 CpG sites. The majority of CpG sites were either highly methylated (> 70%, 52.5–64.6% of all CpG sites analyzed) or unmethylated (< 30%, 22.5–28.0% of all CpG sites analyzed) which are methylation patterns similar to other species. The overall methylation status of CpG sites across the 32 methylomes were remarkably similar. However, the tissue types were clearly defined by principle component analysis and hierarchical clustering analysis with DNA methylome. We found 6416 CpG sites located closely at promoter region of genes and inverse correlation between DNA methylation and gene expression of these genes. Our study provides basic dataset for DNA methylation profiles in dogs.

Deficiency in Vitamin B12 and Ferritin Is Associated With Epigenetic Alterations in Cancer Patients

Background: Cancer is the second-leading cause of death worldwide, caused by several mutations in DNA within the cells including epigenetic alteration. The epigenetic changes are external modifications to the DNA that switch “on” or “off” gene expression. The present study was conducted to investigate the epigenetic modifications and its correlation with the levels of vitamin B12 and ferritin in cancer patients with hepatocellular carcinoma (HCC), breast cancer (BC), lung cancer (LC), or colon cancer (CC). Methods and Results: A total of 200 blood samples were obtained from cancer patients and healthy individuals. The relative expression of DNA methyltransferases (DNMTs), Ten-Eleven translocation (TET), and methionine synthase (MS) was evaluated in patients with the normal level of vitamin B12/ferritin and patients with the deficient levels of them. DNA methylation within the promoter regions was investigated of each indicated genes using the methylation-sensitive restriction enzyme HpaII and bisulfite PCR. Interestingly, the expression of DNMT1, DNMT3a, and DNMT3b was increased in patients with low levels of vitamin B12 and ferritin, while the expression of MS, TET1, and TET3 was significantly decreased. DNA methylation analysis in patients with deficient levels of vitamin B12/ferritin showed a methylated-cytosine within the location 318/CG and 385/CG in the promoter region of TET1 and TET3, respectively. Moreover, the bisulfite PCR assay further confirmed the methylation changes in the promoter region of TET1 and TET3 at the indicated locations. Conclusion: These data indicate that the deficiency in vitamin B12 and ferritin in cancer patients plays a key role in the epigenetic exchanges during cancer development.

Epigenetic Variability Among Saffron Crocus (Crocus sativus L.) Accessions Characterized by Different Phenotypes

This work represents the first epigenomic study carried out on saffron crocus. Five accessions of saffron, showing differences in tepal pigmentation, yield of saffron and flowering time, were analyzed at the epigenetic level by applying a methylation-sensitive restriction enzyme-sequencing (MRE-seq) approach. Five accession-specific hypomethylomes plus a reference hypomethylome, generated by combining the sequence data from the single accessions, were obtained. Assembled sequences were annotated against existing online databases. In the absence of the Crocus genome, the rice genome was mainly used as the reference as it is the best annotated genome among monocot plants. Comparison of the hypomethylomes revealed many differentially methylated regions, confirming the high epigenetic variability present among saffron accessions, including sequences encoding for proteins that could be good candidates to explain the accessions’ alternative phenotypes. In particular, transcription factors involved in flowering process (MADS-box and TFL) and for the production of pigments (MYB) were detected. Finally, by comparing the generated sequences of the different accessions, a high number of SNPs, likely having arisen as a consequence of the prolonged vegetative propagation, were detected, demonstrating surprisingly high genetic variability. Gene ontology (GO) was performed to map and visualize sequence polymorphisms located within the GOs and to compare their distributions among different accessions. As well as suggesting the possible existence of alternative phenotypes with a genetic basis, a clear difference in polymorphic GO is present among accessions based on their geographic origin, supporting a possible signature of selection in the Indian accession with respect to the Spanish ones.

Deficiency in vitamin B12 and ferritin is associated with epigenetic alterations in cancer patients

Background: Cancer is the second-leading cause of death worldwide, caused by several mutations in DNA within the cells including epigenetic alteration. The epigenetic changes are external modifications to the DNA that switch “on” or “off” gene expression. The present study was conducted to investigate the epigenetic modifications and its correlation with the levels of vitamin B12 and ferritin in cancer patients with hepatocellular carcinoma (HCC), breast cancer (BC), lung cancer (LC), or colon cancer (CC). Methods and Results: A total of 200 blood samples were obtained from cancer patients and healthy individuals. The relative expression of DNA methyltransferases (DNMTs), Ten-Eleven translocation (TET), and methionine synthase (MS) was evaluated in patients with the normal level of vitamin B12/ferritin and patients with the deficient levels of them. DNA methylation within the promoter regions was investigated of each indicated genes using the methylation-sensitive restriction enzyme HpaII and bisulfite PCR. Interestingly, the expression of DNMT1, DNMT3a, and DNMT3b was increased in patients with low levels of vitamin B12 and ferritin, while the expression of MS, TET1, and TET3 was significantly decreased. DNA methylation analysis in patients with deficient levels of vitamin B12/ferritin showed a methylated-cytosine within the location 318/CG and 385/CG in the promoter region of TET1 and TET3, respectively. Moreover, the bisulfite PCR assay further confirmed the methylation changes in the promoter region of TET1 and TET3 at the indicated locations. Conclusion: These data indicate that the deficiency in vitamin B12 and ferritin in cancer patients plays a key role in the epigenetic exchanges during cancer development.

DNA Methylation Landscape of 16 Canine Somatic Tissues by Methylation-Sensitive Restriction Enzyme-Based Next Generation Sequencing

Background: DNA methylation plays important functions in gene expression regulation that is involved in individual development and various diseases. DNA methylation has been well studied in human and model organisms, but only limited data exist in companion animals like dog. Results: Using methylation-sensitive restriction enzyme-based next generation sequencing (Canine DREAM), we obtained canine DNA methylation maps from 16 somatic tissues. In total, we evaluated 130,861 CpG sites. The majority of CpG sites were either highly methylated (>70%, 52.5%-64.6% of all CpG sites analyzed) or unmethylated (<30%, 22.5%-28.0% of all CpG sites analyzed) which are methylation patterns similar to other species. The overall methylation status of CpG sites across the 32 methylomes were remarkably similar. However, the tissue types were clearly defined by principle component analysis and hierarchical clustering analysis with DNA methylome. We found 6416 CpG sites located closely at promoter region of genes and inverse correlation between DNA methylation and gene expression of these genes. Conclusions: Our study provides basic dataset for DNA methylation profiles in dogs.

ITIH5 and ECRG4 DNA Methylation Biomarker Test (EI-BLA) for Urine-Based Non-Invasive Detection of Bladder Cancer

Bladder cancer is one of the more common malignancies in humans and the most expensive tumor for treating in the Unites States (US) and Europe due to the need for lifelong surveillance. Non-invasive tests approved by the FDA have not been widely adopted in routine diagnosis so far. Therefore, we aimed to characterize the two putative tumor suppressor genes ECRG4 and ITIH5 as novel urinary DNA methylation biomarkers that are suitable for non-invasive detection of bladder cancer. While assessing the analytical performance, a spiking experiment was performed by determining the limit of RT112 tumor cell detection (range: 100–10,000 cells) in the urine of healthy donors in dependency of the processing protocols of the RWTH cBMB. Clinically, urine sediments of 474 patients were analyzed by using quantitative methylation-specific PCR (qMSP) and Methylation Sensitive Restriction Enzyme (MSRE) qPCR techniques. Overall, ECRG4-ITIH5 showed a sensitivity of 64% to 70% with a specificity ranging between 80% and 92%, i.e., discriminating healthy, benign lesions, and/or inflammatory diseases from bladder tumors. When comparing single biomarkers, ECRG4 achieved a sensitivity of 73%, which was increased by combination with the known biomarker candidate NID2 up to 76% at a specificity of 97%. Hence, ITIH5 and, in particular, ECRG4 might be promising candidates for further optimizing current bladder cancer biomarker panels and platforms.