COVID-19 represents a public health emergency, whose mechanism of which is not fully understood. It is speculated that microRNAs may play a crucial role in host cells after infection by SARS-CoV-2. Thus, our study aimed to analyze the expression of miR-200c-3p in saliva samples from patients with COVID-19. One handred eleven samples from patients with COVID-19 were divided into 4 groups. Group I: 39 patients negative for Covid-19; Group II: 37 positive and symptomatic patients, with no indication of hospitalization; Group III: 21 patients with respiratory disorders (hospitalized); Group IV: 14 patients with severe conditions (oxygen therapy). The expression levels of miR-200c-3p were determined using qPCR. We found greater expression of miR-200c-3p in patients in group IV (p <0.0001), and also verified that patients aged ≥42 years had a higher expression of this miR (p =0.013). Logistic regression analysis revealed that the expression of miR-200c-3p and systemic arterial hypertension are factors independently associated with patients in group IV (p <0.0001). Our results suggest that miR-200c-3p is a predictor of severity independent of COVID-19 risk factors, which could represent a way of screening patients affected by SARS-CoV-2.

The acquisition of a castration-resistant prostate cancer phenotype by prostate cancer cells is the alteration that has the worst prognosis for patients. The aim of this study was to evaluate the role of the microRNAs-23b/-27b as well as the possible CCNG1 target gene in tissue samples from patients with localized prostate cancer that progressed to castration-resistant prostate cancer and in a castration-resistant prostate cancer cell line (PC-3). The microRNAs and target gene expression levels of the surgical specimens were analyzed by quantitative real-time polymerase chain reaction. The prostate cancer cell line, PC-3, was transfected with pre-miR-23b, pre-miR-27b, and their respective controls using Lipofectamine RNAiMAX and exposed or not to flutamide. After transfections, expression levels of both the microRNAs and the gene, CCNG1, were analyzed by quantitative real-time polymerase chain reaction. The apoptosis and cell cycle assays were performed on the mini MUSE cytometer. MicroRNAs-23b/-27b were underexpressed in surgical specimens of prostate cancer; however, their target gene, CCNG1, was overexpressed in 69% of the cases. After transfection with the microRNAs-23b/-27b and flutamide, we observed a reduction in gene expression compared with cells that were treated only with microRNAs or only with flutamide. In the apoptosis assay, we demonstrated cell sensitization following transfection with microRNAs-23b/-27b and potentiation when co-administered with flutamide. The number of cells in apoptosis was almost three times higher with the simultaneous treatments (miR + flutamide) compared with the control (p < 0.05). In the cell cycle assay, only flutamide treatment showed better results; a higher number of cells were found in the G0-G1 phase, and a lower percentage of cells completed the final phase of the cycle (p < 0.05). We conclude that microRNAs-23b/-27b are downexpressed in prostate cancer, and their target gene, CCNG1, is overexpressed. We postulated that microRNAs-23b/-27b sensitize the PC-3 cell line and that after the addition of flutamide in the apoptosis assay, we would observe synergism in the treatments between miR and flutamide. In the cell cycle assay, the use of flutamide was sufficient to decrease the number of cells in mitosis. Therefore, we postulate that microRNAs, along with other drugs, may become very useful therapeutic tools in the treatment of castration-resistant prostate cancer.

Prostate cancer (PCa) has a high prevalence and represents an important health problem, with an increased risk of metastasis. With the advance of CRISPR-Cas9 genome editing, new possibilities have been created for investigating PCa. The technique is effective in knockout oncogenes, reducing tumor resistance. MMP9 and miR-21 target genes are associated with PCa progression; therefore, we evaluated the MMP-9 and miR-21 targets in PCa using the CRISPR-Cas9 system. Single guide RNAs (sgRNAs) of MMP9 and miR-21 sequences were inserted into a PX-330 plasmid, and transfected in DU145 and PC-3 PCa cell lines. MMP9 and RECK expression was assessed by qPCR, WB, and IF. The miR-21 targets, integrins, BAX and mTOR, were evaluated by qPCR. Flow cytometry was performed with Annexin5, 7-AAD and Ki67 markers. Invasion assays were performed with Matrigel. The miR-21 CRISPR-Cas9-edited cells upregulated RECK, MARCKS, BTG2, and PDCD4. CDH1, ITGB3 and ITGB1 were increased in MMP9 and miR-21 CRISPR-Cas9-edited cells. Increased BAX and decreased mTOR were observed in MMP9 and miR-21 CRISPR-Cas9-edited cells. Reduced cell proliferation, increased apoptosis and low invasion in MMP9 and miR-21 edited cells was observed, compared to Scramble. CRISPR-Cas9-edited cells of miR-21 and MMP9 attenuate cell proliferation, invasion and stimulate apoptosis, impeding PCa evolution.

Clear cell renal cell carcinoma (ccRCC) is the third most common urological cancer in adults. Our aim is to evaluate genes and miRNAs expression profiles involved with angiogenesis and tumor characteristics in ccRCC. The expression levels of miRNAs miR-99a, 99b, 100; 199a; 106a; 106b; 29a; 29b; 29c; 126; 200a, 200b and their respective target genes: mTOR, HIF1-α, VHL, PDGF, VEGF, VEGFR1 and VEGFR2 were analyzed using qRT-PCR in tumor tissue samples from 56 patients with ccRCC. Five samples of benign renal tissue were utilized as control. The expression levels of miRNAs and genes were related to tumor size, Fuhrman nuclear grade and microvascular invasion. miR99a was overexpressed in most samples and its target gene mTOR was underexpressed, this also occurs for miRNAs 106a, 106b, and their target gene VHL. An increase in miR-200b was correlated with high-risk tumors (p = 0.01) while miR-126 overexpression was associated with Fuhrman’s low grade (p = 0.03). Our results show that in ccRCC there are changes in miRNAs expression affecting gene expression that could be important in determining the aggressiveness of this lethal neoplasia.