SARS-CoV-2: Evolution and Emergence of New Viral Variants.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent responsible for the coronavirus disease 2019 (COVID-19). The high rate of mutation of this virus is associated with a quick emergence of new viral variants that have been rapidly spreading worldwide. Several mutations have been documented in the receptor-binding domain (RBD) of the viral spike protein that increases the interaction between SARS-CoV-2 and its cellular receptor, the angiotensin-converting enzyme 2 (ACE2). Mutations in the spike can increase the viral spread rate, disease severity, and the ability of the virus to evade either the immune protective responses, monoclonal antibody treatments, or the efficacy of current licensed vaccines. This review aimed to highlight the functional virus classification used by the World Health Organization (WHO), Phylogenetic Assignment of Named Global Outbreak (PANGO), Global Initiative on Sharing All Influenza Data (GISAID), and Nextstrain, an open-source project to harness the scientific and public health potential of pathogen genome data, the chronological emergence of viral variants of concern (VOCs) and variants of interest (VOIs), the major findings related to the rate of spread, and the mutations in the spike protein that are involved in the evasion of the host immune responses elicited by prior SARS-CoV-2 infections and by the protection induced by vaccination.

Clinical pathology, diagnostic and treatment in SARS-CoV-2 infection. / Patología clínica, diagnóstico y tratamiento en la infección por SARS-CoV-2.

SARS-CoV-2 is a new virus causing an infection and illness referred to as COVID-19. As of July 7th of 2020, this virus has been associated worldwide with over 12 million of infections and more than 550,000 deaths. Transmission rate of SARS-CoV-2 in the population is high, and the origin of this coronavirus appears to be related to some species of the bat. However, scientific information related to the pathogenesis, and immune response to COVID-19 changes rapidly, which is why the aim of this work is to provide recent information related to an exacerbated inflammatory immune response which causes multiorgan failure and patient death. The timely identification of infected individuals will be key to stop the spread of infection and in severe cases to establish optimal strategies to reduce the risk of death in critically ill patients. In this review, we have considered the latest findings collected from the clinical studies, diagnostic tests, and treatment for COVID-19. Information presented here will help to the better understanding of this disease.

El SARS-CoV-2 es un nuevo virus que causa la enfermedad denominada COVID-19. Este virus ha generado hasta el 7 de julio de 2020 12 millones de contagios y más de 550 000 muertes en todo el mundo. Se sabe que la tasa de transmisión es muy alta y su origen está relacionado con una especie del murciélago. Sin embargo, la información científica relacionada con la COVID-19 cambia rápidamente, por lo que este trabajo tiene como objetivo aportar información reciente y relacionada con el desarrollo de la respuesta inflamatoria exacerbada, que con frecuencia causa falla orgánica múltiple y muerte del paciente. La rápida identificación de los individuos infectados es clave para detener la propagación de esta enfermedad y en los casos más graves establecer estrategias que permitan la reducción de la infección y del riesgo de muerte. En esta revisión, hemos considerado los últimos hallazgos recopilados de los estudios clínicos, pruebas diagnósticas y de tratamiento para COVID-19. La información presentada en este trabajo contribuirá al entendimiento de esta enfermedad.

NF-κB Participates in the Stem Cell Phenotype of Ovarian Cancer Cells.

BACKGROUND: NF-κB is a transcription factor involved in cancer stem cells maintenance of many tumors. Little is known about the specific stem-associated upstream regulators of this pathway in ovarian cancer. The Aim of the study was to analyze the role of the canonical and non-canonical NF-κB pathways in stem cells of ovarian cancer cell lines. METHODS: Stem cells were isolated using sorting cytometry. Western blot and RT-PCR were used to quantify protein and messenger RNA levels. Loss and gain of function assays were performed using siRNAs and dominant-negative proteins, respectively. NF-κB binding activity was measured with a reporter gene assay. The stem phenotype was estimated with clonogenic assays using soft agar, colony formation, ovospheres formation and in vivo tumorigenicity assays. RESULTS: The CD44+ subpopulation of SKOV3 ovarian cancer cell line presented higher mRNA levels of key stemness genes, an increased tumorigenic capacity and higher expression of the RelA, RelB and IKKα. When the canonical pathway was inhibited by means of a dominant-negative version of IkBα, the stem cell population was reduced, as shown by a reduced CD44+ subpopulation, a decrease in the expression of the stemness genes and a reduction of the stem phenotype. In addition, IKKα, the main upstream non-canonical kinase, was highly expressed in the CSC population. Accordingly, when IKKα was inhibited using shRNAs, the expression of the stemness genes was reduced. CONCLUSIONS: This report is the first to show the importance of several elements of both NF-κB pathway in maintaining the ovarian cancer stem cell population.

NF-kappaΒ-inducing kinase regulates stem cell phenotype in breast cancer.

Breast cancer stem cells (BCSCs) overexpress components of the Nuclear factor-kappa B (NF-κB) signaling cascade and consequently display high NF-κB activity levels. Breast cancer cell lines with high proportion of CSCs exhibit high NF-κB-inducing kinase (NIK) expression. The role of NIK in the phenotype of cancer stem cell regulation is poorly understood. Expression of NIK was analyzed by quantitative RT-PCR in BCSCs. NIK levels were manipulated through transfection of specific shRNAs or an expression vector. The effect of NIK in the cancer stem cell properties was assessed by mammosphere formation, mice xenografts and stem markers expression. BCSCs expressed higher levels of NIK and its inhibition through small hairpin (shRNA), reduced the expression of CSC markers and impaired clonogenicity and tumorigenesis. Genome-wide expression analyses suggested that NIK acts on ERK1/2 pathway to exert its activity. In addition, forced expression of NIK increased the BCSC population and enhanced breast cancer cell tumorigenicity. The in vivo relevance of these results is further supported by a tissue microarray of breast cancer samples in which we observed correlated expression of Aldehyde dehydrogenase (ALDH) and NIK protein. Our results support the essential involvement of NIK in BCSC phenotypic regulation via ERK1/2 and NF-κB.