ABSTRACT
Objective To investigate the effect of long non-coding RNA (lncRNA) LNC01309 on the proliferation and migration abilities of human hepatocellular carcinoma (HCC) cells and its mechanism of action. Methods HCC samples and corresponding adjacent tissue samples were collected from 12 patients with HCC who underwent surgical treatment in The Sixth Medical Center of PLA General Hospital from February 2018 to June 2019, and quantitative real-time PCR was used to measure the relative expression level of LNC01309. Quantitative real-time PCR was also used to measure the expression level of LNC01309 in human hepatoma cell lines (HepG2, SNU-398, and Hep3B) and the human immortalized normal liver cell line THLE-2. After LNC01309 was overexpressed in HepG2 cells, the cells were divided into plasmid control group (pEXP-control) and overexpression group (pEXP-LNC01309). CCK-8 assay was used to observe the change in cell proliferation, and wound healing assay and Transwell assay were used to observe migration ability. RNA co-immunoprecipitation was used to detect the interaction between LNC01309 with RBM38, with cells divided into IgG group and RBM38 antibody group, and cycloheximide chase assay was used to analyze the effect of LNC01309 on the stability of RBM38 protein. RBM38 was overexpressed in HepG2 cells to conduct the recovery experiment, and CCK-8 assay, wound healing assay, and Transwell assay were used to observe the changes in cell proliferation and migration abilities. The t -test was used for comparison of continuous data between two groups. Results The mean expression level of LNC01309 in HCC tissue was significantly higher than that in adjacent tissue (4.225±2.285 vs 1.541±0.530, t =3.618, P =0.004), and the relative expression level of LNC01309 in hepatoma cells (HepG2, SNU-398, and Hep3B) was also significantly higher than that in normal hepatocytes (THLE-2) ( t =4.231、6.489、14.480, all P < 0.05). Compared with the control group, HepG2 cells with the overexpression of LNC01309 had significant increases in growth rate (OD 450 value at 96 hours: 1.885±0.107 vs 2.527±0.234, t =4.330, P =0.012) and migration ability (11.65%±2.40% vs 35.66%±4.90%, t =9.837, P < 0.001; 100.00%±3.11% vs 161.00%±35.93%, t =4.399, P =0.005); however, the upregulated proliferation and migration abilities of hepatoma cells induced by LNC01309 overexpression were partially inhibited by RBM38 (OD 450 value at 96 hours: 2.500±0.227 vs 1.913±0.282, t =2.812, P =0.048; 168.00%±9.43% vs 117.20%±18.03%, t =6.622, P < 0.001). Compared with the IgG control group, RBM38 antibody significantly enriched the precipitation of LNC01309 ( t =3.846, P =0.031). The results of cycloheximide chase assay showed that the LNC01309 overexpression group had a significant reduction in the stability of RBM38 protein ( t =8.038, P =0.001). Conclusion The newly identified LNC01309 reduces the stability of RBM38 protein through interaction with RBM38 and promotes the proliferation and migration of HCC cells.
ABSTRACT
SARS-CoV-2 is the causative agent for the COVID-19 pandemic and there is an urgent need to understand the cellular response to SARS-CoV-2 infection. Beclin-1 is an essential scaffold autophagy protein that forms two distinct subcomplexes with modulators Atg14 and UVRAG, responsible for autophagosome formation and maturation, respectively. In the present study, we found that SARS-CoV-2 infection triggers an incomplete autophagy response, elevated autophagosome formation but impaired autophagosome maturation, and declined autophagy by genetic knockout of essential autophagic genes reduces SARS-CoV-2 replication efficiency. By screening 28 viral proteins of SARS-CoV-2, we demonstrated that expression of ORF3a alone is sufficient to induce incomplete autophagy. Mechanistically, SARS-CoV-2 ORF3a interacts with autophagy regulator UVRAG to facilitate Beclin-1-Vps34-Atg14 complex but selectively inhibit Beclin-1-Vps34-UVRAG complex. Interestingly, although SARS-CoV ORF3a shares 72.7% amino acid identity with the SARS-CoV-2 ORF3a, the former had no effect on cellular autophagy response. Thus, our findings provide the mechanistic evidence of possible takeover of host autophagy machinery by ORF3a to facilitate SARS-CoV-2 replication and raises the possibility of targeting the autophagic pathway for the treatment of COVID-19.
ABSTRACT
The ongoing coronavirus disease (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a global public health concern due to relatively easy person-to-person transmission and the current lack of effective antiviral therapy. However, the exact molecular mechanisms of SARS-CoV-2 pathogenesis remain largely unknown. We exploited an integrated proteomics approach to systematically investigate intra-viral and virus-host interactomes for the identification of unrealized SARS-CoV-2 host targets and participation of cellular proteins in the response to viral infection using peripheral blood mononuclear cells (PBMCs) isolated from COVID-19 patients. Using this approach, we elucidated 251 host proteins targeted by SARS-CoV-2 and more than 200 host proteins that are significantly perturbed in COVID-19 derived PBMCs. From the interactome, we further identified that non-structural protein nsp9 and nsp10 interact with NKRF, a NF-[Kcy]B repressor, and may precipitate the strong IL-8/IL-6 mediated chemotaxis of neutrophils and overexuberant host inflammatory response observed in COVID-19 patients. Our integrative study not only presents a systematic examination of SARS-CoV-2-induced perturbation of host targets and cellular networks to reflect disease etiology, but also reveals insights into the mechanisms by which SARS-CoV-2 triggers cytokine storms and represents a powerful resource in the quest for therapeutic intervention.
ABSTRACT
BACKGROUND@#Flubendazole is an anthelmintic and categorized in benzimidazole. Previous evidence indicates its suppression on proliferation of colon cancer and breast cancer cells. Our study aims to explore the effects of flubendazole on non-small cell lung cancer A549 and H460 cell lines and the underlying mechanism.@*METHODS@#CCK-8 assay was used to detect the effect of flubendazole at different concentrations on viability of both cell lines A549 and H460. We used western blot to detect the expression levels of autophagy-related proteins p62 and LC3 after flubendazole treatment. Cells were transfected with tandem fluorescent adenovirus (mRFP-GFP-LC3), and the impact of flubendazole treatment on autophagic flux were analyzed.@*RESULTS@#Cell viability analysis showed a dose-dependent inhibitory effect on proliferation of both A549 and H460, comparing to cells without flubendazole treating (P<0.001). Level of p62 decreased and LC3 II/I ratio increased in cells treated with 2 μmol/L flubendazole for 24 h and 48 h, compared to control groups (P<0.005). Red fluorescence signals increased in mRFP-GFP-LC3 transfected cells after flubendazole treating, suggesting an elevation in autophagic flux.@*CONCLUSIONS@#Flubendazole may inhibit the proliferation of A549 and H460 cells and promote autophagy.
ABSTRACT
The virome in genital tract secretion samples collected from 80 dairy cattle in Shanghai, China, was characterized. Viruses detected included members of the families Papillomaviridae, Polyomaviridae, Hepeviridae, Parvoviridae, Astroviridae, Picornaviridae, and Picobirnaviridae. A member of a new species within the genus Dyoxipapillomavirus and six circular Rep-encoding single-stranded DNA (ssDNA) (CRESS-DNA) viral genomes were fully sequenced and phylogenetically analyzed. The prevalence of bovine polyomaviruses 1 and 2 was measured by PCR to be 10% (8/80) and 6.25% (5/80), respectively. PCR screening also indicated that the novel papillomavirus ujs-21015 and bovine herpesvirus 6 were present in three and two out of the 80 samples, respectively.
