Gene mutation and pathogenesis bacteria are highly associated with colorectal cancer (CRC) development and progression. Autophagy is a self-clearance pathway to degrade abnormal proteins and infected bacteria in cells. Autophagy plays a dual role in cancer development. Among the autophagy-related (ATG) proteins, ATG5 is the key component required for the core machinery of autophagy. However, the role of ATG5 in CRC malignancy remains unclear. Herein, we found that a high ATG5 protein level was correlated with poor overall survival (OS) and disease-free survival (DFS) of 118 patients with CRC. After stratification with demographic and clinicopathologic factors, a high ATG5 protein level was significantly correlated with unfavorable overall survival in female and elder (>60 year) CRC patients and tumor tissues with poor differentiation, late T stages (III + IV), whereas the ATG5 protein level was positively associated with the overall survival in CRC patients without lymph node invasion and radiation therapy. In contrast, a high ATG5 protein level was significantly associated with worse DFS in CRC patients with early stage of AJCC and no radiation therapy. In addition, colorectal cancer cells stably harboring small interfering RNA (siRNA) against ATG5 diminished the tumorsphere formation and sensitized cancer cells to chemotherapeutic agents. Taken together, our results suggest that ATG5 might be a prognostic biomarker for CRC and a potential therapeutic target for CRC patients.

Tumor Susceptibility Gene 101 (TSG101) is a member of endosomal sorting complexes responsible for endocytic pathway, which is associated with autophagic process. However, the role of TSG101 in autophagy remains unclear. To investigate the effect of TSG101 on the membrane-bound MAP1LC3-II, p62 and ubiquitinated protein levels in neuron cells, immunoblotting was used to evaluate the effects in cells silenced with siRNA against TSG101 and treated with autophagy inducer rapamycin. GFP-MAP1LC3 and tandem fluorescent-tagged LC3 (mTagRFP-mWasabi-MAP1LC3) reporter vectors were used to monitor autophagy in cells using confocal microcopy. The autophagic vacuoles were further validated with transmission electron microscopy. Our results showed that TSG101 expression was slightly increased in neuron cells when exposed to rapamycin. Depletion of TSG101 with siRNA lead to accumulation of MAP1LC3-II, GFP-MAP1LC3 puncta and autophagic vacuoles in the cells. Rapamycin-elevated MAP1LC3-II turnover and RFP+Wasabi- puncta were repressed in TSG101 silenced cells, indicating that TSG101 is involved in rapamycin-induced autophagic flux in cells. Moreover, silencing TSG101 reduced colocalization of Rab7, MAP1LC3 and cell viability, increased p62, ubiquitinated proteins in the neuron cells. Taken together, our results suggested that TSG101 might be required for amphisome formation to promote autophagic flux in neuron cells when exposed to rapamycin.

The term cytokine storm refers to an uncontrolled overproduction of soluble inflammatory markers known as cytokines and chemokines. Autoimmune destruction of the lungs triggered by the release of these inflammatory markers often induces acute respiratory distress syndrome (ARDS). ARDS is an emergency condition with a high mortality rate in COVID-19 patients. Dexamethasone is the first repurposed corticosteroid with life-saving efficacy in patients with severe SARS-CoV-2 infection. Dexamethasone has traditionally been known to suppress the production of inflammatory markers at the transcriptional level, but its role as a direct therapeutic to neutralize cytokines, chemokines, their receptors, and functionally critical SARS-CoV-2 proteins has not yet been explored. Herein, we demonstrated that dexamethasone binds with high affinity to interlukin-1 (IL-1), IL-6, IL-8, IL-12, IL-21, INF2, TGFβ-1, INF-γ, CXCL8, some of the receptors, IL-1R, IL-21R, IFNGR, INFAR, IL-6αR-gp130, ST2 and the SARS-CoV-2 protein NSP macro X, and 3CLpro, forming stable drug–protein complexes. Our work implied that dexamethasone has the potential to directly neutralize inflammatory markers, further supporting its life-saving potential in patients with severe manifestations of COVID-19.

Developing countries such as Belize have been facing profound challenges in their quest to effectively track cases of Coronavirus Disease 2019 (COVID-19) and contain the pandemic within their own territory. We assume that at the heights of a COVID-19 wave the number of daily reported cases are substantially lower (often under-reported) than the true number of cases that exist and are reported on a daily basis. Here, we attempt to quantitatively derive the number of daily undetected cases of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Belize. We also used the Markov's Model to correlate the current mortality rate in Belize with the reported incidence of SARS-CoV-2 infections in Belize. We also proposed a differential mathematical model for estimating a dynamic mortality rate. Finally, we demonstrated the ability to estimate the wavelength and amplitude of a COVID-19 wave. Nations worldwide can anticipate two COVID-19 waves annually with an average of 3 months apart. How vaccines and emerging variants potentially skew the amplitude of a COVID-19 wave requires further inquiry. Our findings are therefore relevant to all countries in their quest to develop and implement swift and versatile national healthcare response measures. The present study, however, is particularly relevant to the countries with underdeveloped healthcare systems. These countries often experience economic and resource challenges around building an effective COVID-19 surveillance system to test and report daily COVID-19 cases.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a newly identified RNA virus that causes the serious infection Coronavirus Disease 2019 (COVID-19). The incidence of COVID-19 is still increasing worldwide despite the summer heat and cool winter. However, little is known about seasonal stability of SARS-CoV-2. Herein, we employ Molecular Dynamics (MD) simulations to explore the effect of temperature on four critical SARS-CoV-2 proteins. Our work demonstrates that the spike Receptor Binding Domain (RBD), Main protease (Mpro), and nonstructural protein 3 (macro X) possesses extreme thermos-stability when subjected to temperature variations rendering them attractive drug targets. Furthermore, our findings suggest that these four proteins are well adapted to habitable temperatures on earth and are largely insensitive to cold and warm climates. Furthermore, we report that the critical residues in SARS-CoV-2 RBD were less responsive to temperature variations as compared to the critical residues in SARS-CoV. As such, extreme summer and winter climates, and the transition between the two seasons, are expected to have a negligible effect on the stability of SARS-CoV-2 which will marginally suppress transmission rates until effective therapeutics are available world-wide.

Purpose ATG4, an autophagy protease, cleaves ATG8 family proteins to activate autophagy, a process linked to cancer progression. This study aimed to design α-helical peptides targeting ATG4 to assess their potential as autophagy inhibitors for cancer therapy. Methods Three α-helical peptides (H1–H3) derived from GBRL2 (a human ATG8 homolog) were synthesized. Their effects on ATG4B activity and binding stability were evaluated using reporter assays and molecular dynamics simulations. Autophagy modulation was analyzed by immunoblotting and confocal microscopy. Anticancer effects were assessed using flow cytometry, fluorescence imaging, tumorsphere models, and xenograft studies. Results Among the peptides, the second helical peptide, GBRL2H2, significantly inhibited ATG4B/A enzymatic activity in vitro. The ATG4 Targeting Peptide (GBRL2H2, termed ATP) fused with the cell-penetrating Tat peptide internalized into cells and reduced intracellular ATG4 activity and autophagic flux, whereas Tat or ATP alone elicited minimal to modest effects. Consistently, Tat-ATP treatment decreased cancer cell viability and colony formation. Additionally, Tat-ATP significantly increased the population of dead cancer cells concomitant with decreased mitophagy and mitochondrial membrane potential, elevated reactive oxygen species (ROS) and caspase-3/7 activity. The observed cell death induced by Tat-ATP was substantially reversed by treatment with ROS scavengers and caspase inhibitors, indicating the involvement of ROS and caspase-mediated cell death pathways. Furthermore, Tat-ATP impaired cancer cell motility and reduced the viability of cancer cell line- and patient-derived tumorspheres. Administration of Tat-ATP also led to a significant reduction in tumor size in a xenograft mouse model. Conclusions These results indicate the Tat-ATP is a novel ATG4 inhibitor, highlighting its potential as an anticancer agent. Graphical Abstract