Colorectal cancer (CRC), the second leading cause of cancer mortality, constitutes a significant global health burden. An accurate, noninvasive detection method for cRc as complement to colonoscopy could improve the effectiveness of treatment. In the present study, SureSelectXT Methyl-Seq was performed on cancerous and normal colon tissues and CLDN1, INHBA and SLC30A10 were found as candidate methylated genes. MethyLight assay was run on formalin-fixed paraffin-embedded (FFPE) and fresh case and control tissues to validate the methylation of the selected gene. the methylation was significantly different (p-values < 2.2e-16) with a sensitivity of 87.17%; at a specificity cut-off of 100% in FFPE tissues. Methylation studies on fresh tissues, indicated a sensitivity of 82.14% and a specificity cut-off of 92% (p-values = 1.163e-07). The biomarker performance was robust since, normal tissues indicated a significant 22.1-fold over-expression of the selected gene as compared to the corresponding CRC tissues (p-value < 2.2e-16) in the FFPE expression assay. In our plasma pilot study, evaluation of the tissue methylation marker in the circulating cell-free DNA, demonstrated that 9 out of 22 CRC samples and 20 out of 20 normal samples were identified correctly. In summary, there is a clinical feasibility that the offered methylated gene could serve as a candidate biomarker for CRC diagnostic purpose, although further exploration of our candidate gene is warranted.Colorectal cancer (CRC) constitutes a significant global health burden, leading to over 862,000 deaths globally in 2018. It is the second main cause of cancer mortality in the world and currently stands as the third most common cancer, with a yearly incidence of over one million and eight thousand cases worldwide 1 . Its leading cause of death is due to liver metastasis with a median survival rate of approximately 30 months. Generally, half of the patients with CRC develop tumor recurrences 2 . For early-diagnosed CRC patients, the 5-year survival rates are approximately 90% but this lowers to less than 10% in patients with extensive metastases. Thus, the most effective approach to reduce CRC incidence and its mortality is early detection of colonic lesions 3 . Fortunately, because of implementation and growth of wide spread cancer screening assays, such as colonoscopy as well as increasingly effective therapies, the mortality rate of CRC is lowering in many countries 2 .
Methylation analysis of circulating cell-free DNA (cirDNA), as a liquid biopsy, has a significant potential to advance the detection, prognosis, and treatment of cancer, as well as many genetic disorders. The role of epigenetics in disease development has been reported in several hereditary disorders, and epigenetic modifications are regarded as one of the earliest and most significant genomic aberrations that arise during carcinogenesis. Liquid biopsy can be employed for the detection of these epigenetic biomarkers. It consists of isolation (pre-analytical) and detection (analytical) phases. The choice of pre-analytical variables comprising cirDNA extraction and bisulfite conversion methods can affect the identification of cirDNA methylation. Indeed, different techniques give a different return of cirDNA, which confirms the importance of pre-analytical procedures in clinical diagnostics. Although novel techniques have been developed for the simplification of methylation analysis, the process remains complex, as the steps of DNA extraction, bisulfite treatment, and methylation detection are each carried out separately. Recent studies have noted the absence of any standard method for the pre-analytical processing of methylated cirDNA. We have therefore conducted a comprehensive and systematic review of the important pre-analytical and analytical variables and the patient-related factors which form the basis of our guidelines for analyzing methylated cirDNA in liquid biopsy.
The latest outbreak of pneumonia caused by SARS-CoV-2 presents a significant challenge to global public health and has a major impact on clinical microbiology laboratories. In some situations, such as patients in coma condition, the oropharyngeal or nasopharyngeal sampling is seldom feasible, and blood sampling could be an alternative. In the current article, a comprehensive literature search has been conducted for detecting coronavirus disease 2019 (COVID-19) using plasma or serum samples. To date, twenty-six studies have used SARS-CoV-2 nucleic acid in plasma or serum (RNAaemia) to diagnose COVID-19. The pros and cons are discussed in this article. While the detection of SARS-CoV-2 viral load in respiratory specimens is commonly used to diagnose COVID-19, detecting SARS-CoV-2 RNA in plasma or serum should not lose sight and it could be considered as an alternative diagnostic approach.
Background:
Thanatin is the smallest member of Beta-hairpin class of cationic peptide
derived from insects with vast activities against various pathogens.
Objective:
n this study, the antimicrobial activity of this peptide against some species of human
bacterial pathogens as well as its toxicity on NIH cells were evaluated.
Method:
Thanatin DNA sequence was cloned into pcDNA3.1+ vector and transformed into a
DH5α bacterial strain. Then the recombinant plasmids were transfected into HEK-293 cells by
calcium phosphate co-precipitation. After applying antibiotic treatment, the supernatant medium
containing thanatin was collected. The peptide quantity was estimated by SDS-PAGE and
GelQuant software. The antimicrobial activity of this peptide was performed with Minimum
Inhibitory Concentration (MIC) method. In addition, its toxicity on NIH cells were evaluated by
MTT assay.
Results:
The peptide quantity was estimated approximately 164.21 µmolL-1. The antibacterial
activity of thanatin was estimated between 0.99 and 31.58 µmolL-1 using MIC method. The result
of cytotoxicity test on NIH cell line showed that the peptide toxicity up to the concentration of
394.10 µmolL-1 and for 48 hours, was not statistically significant from negative control cells
(P>0.05). The antimicrobial assay demonstrated that thanatin had an antibacterial effect on some
tested microorganisms. The results obtained in this study also showed that thanatin had no toxicity
on mammalian cell lines including HEK293 and NIH.
Conclusion:
Antimicrobial peptides such as thanatin are considered to be appropriate alternatives
to conventional antibiotics in treating various human pathological diseases bacteria.
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