Mesencephalic Astrocyte-Derived Neurotrophic Factor Inhibits Liver Cancer Through Small Ubiquitin-Related Modifier (SUMO)ylation-Related Suppression of NF-κB/Snail Signaling Pathway and Epithelial-Mesenchymal Transition.

BACKGROUND AND AIMS: Endoplasmic reticulum (ER) stress is associated with liver inflammation and hepatocellular carcinoma (HCC). However, how ER stress links inflammation and HCC remains obscure. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an ER stress-inducible secretion protein that inhibits inflammation by interacting with the key subunit of nuclear factor kappa light chain enhancer of activated B cells (NF-κB) p65. We hypothesized that MANF may play a key role in linking ER stress and inflammation in HCC. APPROACH AND RESULTS: Here, we found that MANF mRNA and protein levels were lower in HCC tissues versus adjacent noncancer tissues. Patients with high levels of MANF had better relapse-free survival and overall survival rates than those with low levels. MANF levels were also associated with the status of liver cirrhosis, advanced tumor-node-metastasis (TNM) stage, and tumor size. In vitro experiments revealed that MANF suppressed the migration and invasion of hepatoma cells. Hepatocyte-specific deletion of MANF accelerated N-nitrosodiethylamine (DEN)-induced HCC by up-regulating Snail1+2 levels and promoting epithelial-mesenchymal transition (EMT). MANF appeared in the nuclei and was colocalized with p65 in HCC tissues and in tumor necrosis factor alpha (TNF-α)-treated hepatoma cells. The interaction of p65 and MANF was also confirmed by coimmunoprecipitation experiments. Consistently, knockdown of MANF up-regulated NF-κB downstream target genes TNF-α, interleukin (IL)-6 and IL-1α expression in vitro and in vivo. Finally, small ubiquitin-related modifier 1 (SUMO1) promoted MANF nuclear translocation and enhanced the interaction of MANF and p65. Mutation of p65 motifs for SUMOylation abolished the interaction of p65 and MANF. CONCLUSIONS: MANF plays an important role in linking ER stress and liver inflammation by inhibiting the NF-κB/Snail signal pathway in EMT and HCC progression. Therefore, MANF may be a cancer suppressor and a potential therapeutic target for HCC.

Xanthatin induces glioma cell apoptosis and inhibits tumor growth via activating endoplasmic reticulum stress-dependent CHOP pathway.

Xanthatin is a natural sesquiterpene lactone purified from Xanthium strumarium L., which has shown prominent antitumor activity against a variety of cancer cells. In the current study, we investigated the effect of xanthatin on the growth of glioma cells in vitro and in vivo, and elucidated the underlying mechanisms. In both rat glioma C6 and human glioma U251 cell lines, xanthatin (1-15 µM) dose-dependently inhibited cell viability without apparent effect on the cell cycle. Furthermore, xanthatin treatment dose-dependently induced glioma cell apoptosis. In nude mice bearing C6 glioma tumor xenografts, administration of xanthatin (10, 20, 40 mg·kg-1·d-1, ip, for 2 weeks) dose-dependently inhibited the tumor growth, but did not affect the body weight. More importantly, xanthatin treatment markedly increased the expression levels of the endoplasmic reticulum (ER) stress-related markers in both the glioma cell lines as well as in C6 xenografts, including glucose-regulated protein 78, C/EBP-homologous protein (CHOP), activating factor 4, activating transcription factor 6, spliced X-box binding protein-1, phosphorylated protein kinase R-like endoplasmic reticulum kinase, and phosphorylated eukaryotic initiation factor 2a. Pretreatment of C6 glioma cells with the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 7 mM) or knockdown of CHOP using small interfering RNA significantly attenuated xanthatin-induced cell apoptosis and increase of proapoptotic caspase-3. These results demonstrate that xanthatin induces glioma cell apoptosis and inhibits tumor growth via activating the ER stress-related unfolded protein response pathway involving CHOP induction. Xanthatin may serve as a promising agent in the treatment of human glioma.

Risk factors on admission associated with hospital length of stay in patients with COVID-19: a retrospective cohort study.

Treating patients with COVID-19 is expensive, thus it is essential to identify factors on admission associated with hospital length of stay (LOS) and provide a risk assessment for clinical treatment. To address this, we conduct a retrospective study, which involved patients with laboratory-confirmed COVID-19 infection in Hefei, China and being discharged between January 20 2020 and March 16 2020. Demographic information, clinical treatment, and laboratory data for the participants were extracted from medical records. A prolonged LOS was defined as equal to or greater than the median length of hospitable stay. The median LOS for the 75 patients was 17 days (IQR 13-22). We used univariable and multivariable logistic regressions to explore the risk factors associated with a prolonged hospital LOS. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated. The median age of the 75 patients was 47 years. Approximately 75% of the patients had mild or general disease. The univariate logistic regression model showed that female sex and having a fever on admission were significantly associated with longer duration of hospitalization. The multivariate logistic regression model enhances these associations. Odds of a prolonged LOS were associated with male sex (aOR 0.19, 95% CI 0.05-0.63, p = 0.01), having fever on admission (aOR 8.27, 95% CI 1.47-72.16, p = 0.028) and pre-existing chronic kidney or liver disease (aOR 13.73 95% CI 1.95-145.4, p = 0.015) as well as each 1-unit increase in creatinine level (aOR 0.94, 95% CI 0.9-0.98, p = 0.007). We also found that a prolonged LOS was associated with increased creatinine levels in patients with chronic kidney or liver disease (p < 0.001). In conclusion, female sex, fever, chronic kidney or liver disease before admission and increasing creatinine levels were associated with prolonged LOS in patients with COVID-19.

Xanthatin induces apoptosis by activating endoplasmic reticulum stress in hepatoma cells.

Hepatocellular carcinoma (HCC) has high incidence and mortality in patients with chronic liver diseases worldwide. However, there are limited chemotherapeutic agents for HCC in clinic. Xanthatin, a natural sesquiterpene lactone, has significant antitumor activity against a variety of cancers, but little is known about its effects on HCC and the underlying mechanism. Here, we evaluated the antitumor effects of xanthatin on human hepatoma cells. We found that xanthatin caused morphological changes and reduced cell viability in three HCC cell lines in concentration- and time-dependent manners. Xanthatin at 10 µM significantly arrested cell cycle at the G2/M checkpoint, and at 40 µM significantly arrested cell cycle at the S phase in hepatoma cells. Additionally, xanthatin induced apoptosis associated with activation of caspase-3 in hepatoma cells, but did not apparently induce apoptosis in human normal LO2 hepatocytes. We also demonstrated that the three primary signaling pathways of unfolded protein response (UPR) were activated by xanthatin to different extents. Notably, the PERK/eIF-2α/ATF4 axis was most significantly activated by xanthatin. More importantly, both xanthatin and tunicamycin, an endoplasmic reticulum stress (ERS) inducing compound, increased the levels of CHOP and cleaved-caspase-3 in HepG2 cells, but their effects were significantly abolished by siRNA-mediated knockdown of CHOP. Further experiments validated that xanthatin more potently activated ATF4 by promoting its nuclear translocation in hepatoma cells. Taken together, we discovered that xanthatin induced apoptosis in human hepatoma cells by activating ERS. Our current data revealed a novel mechanism for xanthatin as a promising anti-tumor candidate for HCC therapy.

Ubiquitin ligase SYVN1/HRD1 facilitates degradation of the SERPINA1 Z variant/α-1-antitrypsin Z variant via SQSTM1/p62-dependent selective autophagy.

SERPINA1/AAT/α-1-antitrypsin (serpin family A member 1) deficiency (SERPINA1/ AAT-D) is an autosomal recessive disorder characterized by the retention of misfolded SERPINA1/AAT in the endoplasmic reticulum (ER) of hepatocytes and a significant reduction of serum SERPINA1/AAT level. The Z variant of SERPINA1/AAT, containing a Glu342Lys (E342K) mutation (SERPINA1E342K/ATZ), the most common form of SERPINA1/AAT-D, is prone to misfolding and polymerization, which retains it in the ER of hepatocytes and leads to liver injury. Both proteasome and macroautophagy/autophagy pathways are responsible for disposal of SERPINA1E342K/ATZ after it accumulates in the ER. However, the mechanisms by which SERPINA1E342K/ATZ is selectively degraded by autophagy remain unknown. Here, we showed that ER membrane-spanning ubiquitin ligase (E3) SYVN1/HRD1 enhances the degradation of SERPINA1E342K/ATZ through the autophagy-lysosome pathway. We found that SYVN1 promoted SERPINA1E342K/ATZ, especially Triton X 100-insoluble SERPINA1E342K/ATZ clearance. However, the effect of SYVN1 in SERPINA1E342K/ATZ clearance was impaired after autophagy inhibition, as well as in autophagy-related 5 (atg5) knockout cells. On the contrary, autophagy induction enhanced SYVN1-mediated SERPINA1E342K/ATZ degradation. Further study showed that SYVN1 mediated SERPINA1E342K/ATZ ubiquitination, which is required for autophagic degradation of SERPINA1E342K/ATZ by promoting the interaction between SERPINA1E342K/ATZ and SQSTM1/p62 for formation of the autophagy complex. Interestingly, SYVN1-mediated lysine 48 (K48)-linked polyubiquitin chains that conjugated onto SERPINA1E342K/ATZ might predominantly bind to the ubiquitin-associated (UBA) domain of SQSTM1 and couple the ubiquitinated SERPINA1E342K/ATZ to the lysosome for degradation. In addition, autophagy inhibition attenuated the suppressive effect of SYVN1 on SERPINA1E342K/ATZ cytotoxicity, and the autophagy inducer rapamycin enhanced the suppressive effect of SYVN1 on SERPINA1E342K/ATZ-induced cell apoptosis. Therefore, this study proved that SYVN1 enhances SERPINA1E342K/ATZ degradation through SQSTM1-dependent autophagy and attenuates SERPINA1E342K/ATZ cytotoxicity.