Hyperglycosylated spike of SARS-CoV-2 gamma variant induces breast cancer metastasis

SARS-CoV-2 exploits the host cellular machinery for virus replication leading to the acute syndrome of coronavirus disease 2019 (COVID-19). Growing evidence suggests SARS-CoV-2 also exacerbates many chronic diseases, including cancers. As mutations on the spike protein (S) emerged as dominant variants that reduce vaccine efficacy, little is known about the relation between SARS-CoV-2 virus variants and cancers. Compared to the SARS-CoV-2 wild-type, the Gamma variant contains two additional NXT/S glycosylation motifs on the S protein. The hyperglycosylated S of Gamma variant is more stable, resulting in more significant epithelial-mesenchymal transition (EMT) potential. SARS-CoV-2 infection promoted NF-κB signaling activation and p65 nuclear translocation, inducing Snail expression. Pharmacologic inhibition of NF-κB activity by nature food compound, I3C suppressed viral replication and Gamma variant-mediated breast cancer metastasis, indicating that NF-κB inhibition can reduce chronic disease in COVID-19 patients. Our study revealed that the Gamma variant of SARS-CoV-2 activates NF-κB and, in turn, triggers the pro-survival function for cancer progression.

Epithelial-mesenchymal transition induced by SARS-CoV-2 required transcriptional upregulation of Snail

The engagement of human angiotensin-converting enzyme 2 (hACE2) and SARS-CoV-2 spike protein facilitate virus spread. Thus far, ACE2 and TMPRSS2 expression is correlated with the epithelial-mesenchymal transition (EMT) gene signature in lung cancer. However, the mechanism for SARS-CoV-2-induced EMT has not been thoroughly explored. Here, we showed that SARS-CoV-2 induces EMT phenotypic change and stemness in breast cancer cell model and subsequently identified Snail as a modulator for this regulation. The in-depth analysis identifies the spike protein (S), but not envelope (E), nucleocapsid (N), or membrane protein (M), of SARS-CoV-2 induces EMT marker changes. Suppression of Snail expression in these cells abrogates S protein-induced invasion, migration, stemness, and lung metastasis, suggesting that Snail is required for SARS-CoV-2-mediated aggressive phenotype in cancer. This study reveals an important oncogenic role of SARS-CoV-2 in triggering breast cancer metastasis through Snail upregulation.

Immune responses and COVID-19 severity

Background: The coronavirus-19-disease (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to >200 countries and surpassed 7 million cases. There is a broad range of COVID-19 illness, ranging from milder disease to a rapidly progressive respiratory disease and ARDS. The causes of this different clinical course and the drivers for severe disease are currently unknown. A fulminant increase of pro-inflammatory cytokines is thought to play a role in causing a rapid disease evolution, however the immune correlates of severe COVID-19 remain unclear. Methods: To gain insight into relationship between immune responses and disease severity we built a longitudinal cohort of 40 adult patients with known COVID- 19. Samples were collected at diagnosis and every 7 days until hospital discharge or death. As controls we also included a group of convalescent patients, and subjects who tested negative for COVID-19 by PCR. Clinical and laboratory data and were also collected. Multicolor flow cytometry was used to determine the presence and phenotype of B, T and natural killer (NK) cells. We also identified specific sub-populations (Tfh, activated/cytotoxic CD8 and NK) and assessed lymphoid exhaustion of different cell types such as naïve, memory T cells, or NK over time. Anti-Sars-CoV2 IgG and IgM antibody were detected using lateral flow method. Results: We found that the absolute number of lymphocytes and monocytes was decreased starting at diagnosis and correlated with disease severity. Disease severity correlated with decreased NK and T cell. In severe COVID-19 cases, NK cell populations were strongly decreased over time in intubated patients while they recovered in patients who improved and were discharged. CD8+ were also decreased at disease onset and seemed to correlate with disease severity. A high percentage of CD4+ and CD8+ T cells showed an exhausted phenotype. All patients tested at admission had IgM antibody responses irrespective of the course of the disease. Further analyses are ongoing. Conclusion: The characterization and role of the immune responses in COVID- 19 evolution is still under investigation. Further characterization of viral and immune factors will help in identifying subjects at high risk of severe disease and targets for intervention.