A Bioluminescent Biosensor for Quantifying the Interaction of SARS-CoV-2 and Its Receptor ACE2 in Cells and In Vitro.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is currently spreading and mutating with increasing speed worldwide. Therefore, there is an urgent need for a simple, sensitive, and high-throughput (HTP) assay to quantify virus-host interactions in order to quickly evaluate the infectious ability of mutant viruses and to develop or validate virus-inhibiting drugs. Here, we developed an ultrasensitive bioluminescent biosensor to evaluate virus-cell interactions by quantifying the interaction between the SARS-CoV-2 receptor binding domain (RBD) and its cellular receptor angiotensin-converting enzyme 2 (ACE2) both in living cells and in vitro. We have successfully used this novel biosensor to analyze SARS-CoV-2 RBD mutants and evaluated candidate small molecules (SMs), antibodies, and peptides that may block RBD:ACE2 interaction. This simple, rapid, and HTP biosensor tool will significantly expedite the detection of viral mutants and the anti-COVID-19 drug discovery process.

Evaluation of circulating miR-21 and miR-222 as diagnostic biomarkers for gastric cancer.

INTRODUCTION: Gastric cancer is responsible for a large number of death worldwide and its high death rate is associated with a lack of noninvasive tools in GC diagnosis. MicroRNAs (miRNAs), as gene regulators, were shown to dysregulate in different types of cancer. Moreover, it is proven that miRNAs are stable in serum/plasma, so they can be used as a potential noninvasive marker in GC diagnosis. The objective of this study is to investigate the plasma miRNA expression in GC samples compared to controls as a potential biomarker in cancer diagnosis. MATERIALS AND METHODS: Expression levels of miR-21 and miR-222 were assessed using quantitative real-time polymerase chain reaction in plasma of 30 GC patients and 30 healthy controls. Diagnostic value of selected miRNAs was evaluated using receiver operating characteristic curve. Target prediction was done using bioinformatics tools to investigate the signaling pathways and function of the selected miRNAs. RESULTS: Our results demonstrated that the expression levels of miR-21 and miR-222 were significantly higher in GC plasma than in the controls (P < 0.0001, P = 0.043). The sensitivity and specificity for miR-21 and in plasma were 86.7% and 72.2% and for miR-222 were 62.5% and 56.2%, respectively. Bioinformatics analysis revealed that most target genes of miR-21 and miR-222 are involved in cancer-related signaling pathway such as tumor initiation and progression. CONCLUSION: Our results indicated that miR-21 and miR-222 in plasma samples can be served as a potential noninvasive tool in GC detection. Furthermore, the miRNA target prediction manifested that miR-21 and miR-222 involve in key processes associated with GC initiation and development.

MicroRNA Expression Levels and Histopathological Features of Colorectal Cancer.

INTRODUCTION: Non-coding RNAs have opened a new window in cancer biology. MicroRNAs (miRNAs), as a family of non-coding RNAs, play an important role in the gene regulation. The aberrant expression of these small molecules has been documented to involve in colorectal cancer (CRC) pathogenesis. This study aimed to examine the expression of miRNAs in CRC and to correlate their expression levels with histological markers (Ki-67 and CD34). MATERIALS AND METHODS: Tumor tissues and matched normal adjacent tissues were collected from 36 patients with newly diagnosed CRC. Immunohistochemical (IHC) staining of tumor tissues was performed for Ki-67 (proliferation) and CD34 (angiogenesis) markers, and the immunoexpression staining scores were obtained. A polyadenylation SYBER Green quantitative real-time PCR technique was used to quantify the expression of a panel of five CRC-related miRNAs (hsa-miR-21, 31, 20a, 133b, and 145). Histopathological (H) scores and miRNA expression levels were correlated with clinicopathological features including the degree of differentiation, staging, and lymphovascular invasion. RESULTS: Our results showed the significant difference between the two groups for the expression level of hsa-miR-21, hsa-miR-31, hsa-miR-145, and miR-20a (P < 0.001), but not for hsa-miR-133b (P = 0.57). Further analysis revealed an inverse significant correlation between hsa-miR-145 and Ki-67 (r = - 0.942, P < 0.001). While a positive correlation was observed between hsa-miR-21 and Ki-67 (r = 0.920, P < 0.001), and hsa-miR-21 and CD34 (r = 0.981, P < 0.001). Also, a positive correlation between hsa-miR-31 and Ki-67 (r = 0.913, P < 0.001), hsa-miR-31 and CD34 (r = 0.798, P < 0.05), hsa-miR-20a and Ki-67 (r = 0.871, P < 0.001), and hsa-miR-20a and CD34 (r = 0.890, P < 0.001) was found. CONCLUSION: Dysregulation of miRNAs and correlation with molecular histopathology indicate a biological role for miRNAs in various cellular processes including cell proliferation and angiogenesis in CRC development. On the other hand, the pattern of miRNA expression and its correlation with histological markers are potentially valuable to apply as diagnostic biomarkers for CRC.