Biology Direct最新文献

Background: Oral squamous cell carcinoma (OSCC) is one of the leading causes of cancer-related mortality worldwide due to its high aggressive potential and drug resistance. Previous studies have revealed an important function of HECT And RLD Domain Containing E3 Ubiquitin Protein Ligase 5 (HERC5) in cancer. Six GEO gene microarrays identified HERC5 as a significant upregulated gene in OSCC tissues or cells (log2 Fold change > 1 and adj.p < 0.05). This study aimed to explore the role and underlying mechanisms of HERC5 in OSCC development.

Results: High HERC5 expression in OSCC tissues was confirmed by our hospital validation cohort and positively correlated with primary tumor stages. Subsequent functional studies demonstrated that knockdown of HERC5 inhibited the migratory and invasive capabilities with decrease of Vimentin and increase of E-cadherin in OSCC cells. In cisplatin treatment, cell survival rates were significantly reduced in HERC5-silencing OSCC cells, accompanied by the increase in cytotoxicity, DNA damage and apoptosis. OSCC cell-derived tumor xenograft displayed that HERC5 depletion inhibited pulmonary metastasis as well as restored the cisplatin-induced tumor burden. In line with this, overexpression of HERC5 yielded the opposite alterations both in vivo and in vitro. Mechanistically, UDP-glucose 6-dehydrogenase (UGDH) was identified as a HERC5-binding protein. Cysteine residue at position 994 in the HECT domain of HERC5 catalyzed the conjugation of ubiquitin-like protein Interferon-induced 15 kDa protein (ISG15) to UGDH (ISGylation of UGDH) and facilitated its phosphorylation, therefore enhancing SNAI1 mRNA stability. SNAI1 depletion inhibited HERC5 overexpression-triggered invasion and cisplatin resistance of OSCC cells.

Conclusions: Our study indicates that HERC5 may be a promising therapeutic target for OSCC.

Background: Hepatocellular carcinoma is a fatal malignancy that lacking specific therapies. Homeobox B4 (HOXB4) was negatively correlated with poor prognosis in cancers, but its role in hepatocellular carcinoma has not been elucidated.

Results: We confirmed that HOXB4 was downregulated in hepatocellular carcinoma tissues and lower HOXB4 expression associated with poor prognosis. Gain- and loss-of function experiments were performed to understand the functional consequences. We revealed that HOXB4 overexpression inhibited proliferation and metastasis of hepatocellular carcinoma cells, accompanied with the decrease in epithelial-mesenchymal transition and increase in cell apoptosis. Database analysis showed that HOXB4 was positively correlated with the immune infiltration. PD-L1 expression was decreased in HOXB4 overexpressed hepatocellular carcinoma cells. HOXB4 overexpression was confirmed to inhibit the progression of hepatocellular carcinoma and promote T cell infiltration in vivo. N6-methyladenosine (m6A) modification was implicated in the tumorigenesis. RNA-seq analysis showed that HOXB4 overexpression modulated METTL7B expression. With the performance of dual-luciferase reporter, ChIP, and DNA pulldown assays, we revealed that HOXB4 binding to METTL7B promoter and inhibited its mRNA expression. The increased aggressiveness of hepatocellular carcinoma cells and the enhanced immune escape, triggered by HOXB4 knockdown, were inhibited via METTL7B downregulation. Methylated RNA immunoprecipitation assay displayed that METTL7B controlled the mRNA decay of TKT in m6A methylation. METTL7B overexpression increase the expression of TKT, ultimately promoting hepatocellular carcinoma progression and immune evasion.

Conclusions: HOXB4 mediated the malignant phenotypes and modulated the immune evasion via METTL7B/TKT axis. The HOXB4/METTL7B cascade and its downstream changes might be novel targets for blocking hepatocellular carcinoma progression.

Background: Nucleolin (NCL) plays an important regulatory role in angiotensin II (Ang II)-induced phenotypic switching of vascular smooth muscle cells (VSMCs). The aim of this study was to discuss its potential regulatory mechanisms.

Results: We investigated if the pathways involving Ang II type 1 receptor (AT1R) and PKC/MAPK are responsible for Ang II's effects on VSMC phenotypic switching. Ang II upregulated NCL expression and activated the PKC/MAPK signaling pathway to induce VSMC phenotypic switching. In addition, Ang II promoted the translocation of NCL from the nucleus to the cell membrane. NCL was shown to bind to AT1R, whereas the binding of NCL to AT1R was greatly attenuated after the deletion of the GAR region. In addition, when peptide-N-glycosidase F (PNGase F) was applied, the N-glycosylation of NCL protein and the phenotypic switching of VSMC were inhibited. Ang II-induced AT1R internalization, whereas overexpression of NCL delayed Ang II-induced AT1R internalization by inhibiting AT1R phosphorylation and recruited Rab4 and Rab11 to promote recycling, and knockdown of NCL showed the opposite effect and reversal of AT1R binding by the use of rasarfin reversed the effects of sh-NCL. In in vivo experiments, knockdown of NCL expression inhibited Ang II-induced blood pressure rise and vasculopathy.

Conclusions: Our study demonstrates that NCL promotes Ang II-mediated phenotypic switching of VSMCs by regulating AT1R internalization function.

Background: Doxorubicin (DOX) is an anthracycline with potent antitumor properties and rare yet serious cardiotoxic side effects that limit its clinical application. The sigma-1 receptor is a stress-triggered chaperone often dysregulated in diseases and has known cardioprotective effects. Although its anti-oxidative stress and anti-apoptotic effects have been demonstrated, its effectiveness in DOX-induced cardiotoxicity has never been explored. This study investigated the potential role of the activated sigma-1 receptor in a DOX-induced murine cardiotoxicity model to elucidate the receptor's mechanism of action.

Methods: We established the model in C57BL/6 mice by daily intraperitoneal injections of fluvoxamine (Flv) for 4 consecutive weeks to activate the receptor and by weekly intraperitoneal injections of DOX at 5 mg/kg for 3 weeks. We performed in vitro experiments using cardiomyocytes of neonatal Sprague-Dawley rats to verify the protective effect of the sigma-1 receptor.

Results: We found that sigma-1 expression in the heart decreased in the DOX-treated mice, and activating the receptor with Flv improved cardiac function. Moreover, Flv pretreatment inhibited cardiomyocyte apoptosis and endoplasmic reticulum stress and increased the expression of the Bcl2 apoptosis regulator (Bcl2), effectively alleviating the pathophysiological manifestations in mice. In addition, activating the receptor exerted cardioprotective effects by modulating endoplasmic reticulum stress through the PRKR-like endoplasmic reticulum kinase (PERK) signaling pathway. It also reduced mitochondrial and endoplasmic reticulum contact and alleviated mitochondrial calcium overload through the IP3R-VDAC1-MCU signaling pathway.

Conclusion: In conclusion, our study emphasizes the therapeutic potential of activating sigma-1 receptors against DOX-induced cardiotoxicity, suggesting sigma-1 receptors as potential therapeutic targets for this disease.

Background: Cellular boundaries of microorganisms can be modified by the expression in the cell wall of specific proteins endowed with relevant properties, improving their functional performance. So far, the surface display (SD) technique had been widely employed in the yeast Saccharomyces cerevisiae, but it was limited to few laboratory strains and never explored in sauvage strains, i.e., isolated from natural environment, which are featured by higher levels of genetic variability, leading to peculiar phenotypic traits of possible advantage in biotechnology.

Results: In this work, a series of plasmids performing SD in natural yeast strains have been generated and further characterized by multiple functional and biochemical assays, providing the first experimental evidence that natural strains of S.cerevisiae can be genetically modified to express on their cell wall a protein-of-interest, which retains its biological competence. Interestingly, data further demonstrated that engineered strains expressing (transiently or stably) metal-binding proteins or peptides on cell surface exhibit significantly enhanced metal adsorption properties.

Conclusions: The molecular tools presented here can be very useful for yeast research community, as the plasmids efficiently support the surface engineering in virtually all S.cerevisiae strains, independently from either genetic background, source, or applications (wine, beer, bread). Overall, data strongly suggest that, upon genetic modification, S. cerevisiae strains isolated from natural environments could serve as promising platforms for biotechnological applications, as heavy metals removal or enzymes immobilization. Importantly, the strains investigated here represent only a small fraction of the multitude of S. cerevisiae strains present in nature yet to be isolated.

Background: The Rho GTPase Rac family small GTPase 1 (RAC1) is considered a promising fibrotic therapeutic target, but the role of its activator, dedicator of cytokinesis 2 (DOCK2), in liver fibrosis is largely unknown. This study aimed to investigate the expression and role of DOCK2 in cholestasis-induced liver fibrosis and to further explore the potential mechanisms.

Results: Cholestasis was induced in male C57BL/6 mice by bile duct ligation (BDL). DOCK2 knockdown was achieved by tail vein injection of adenovirus containing DOCK2-targeting shRNA. The effect of DOCK2 knockdown on cholestatic liver injury was evaluated at different time points after BDL. Hepatic DOCK2 expression gradually increased after BDL. Knockdown of DOCK2 reduced the necrotic area in BDL liver and downregulated serum levels of liver injury indicators. At 3d post-BDL (acute phase), DOCK2 knockdown alleviated M1 macrophage inflammation in the liver, as evidenced by reduced infiltrating iNOS + macrophages and inflammatory cytokines and mitigated NLRP3 inflammasome activation. At 14d post-BDL (chronic phase), DOCK2 knockdown suppressed hepatic stellate cell (HSC) activation and liver fibrosis as indicated by decreased α-SMA + HSCs and extracellular matrix deposition. In vitro experiments further demonstrated that DOCK2 knockdown suppressed M1 macrophage polarisation and HSC to myofibroblast transition, accompanied by inhibition of RAC1 activation.

Conclusions: In summary, this study demonstrates for the first time that the RAC1 activator DOCK2 regulates M1 macrophage polarisation and hepatic stellate cell activation to promote cholestasis-induced liver inflammation and fibrosis, suggesting that DOCK2 may be a potential therapeutic target in cholestatic liver injury.

Members from the RAS GTPase superfamily have been closely implicated in the tumorigenesis of various human cancers. Recent sequencing analysis of lung adenocarcinoma has revealed the prevalence of alterations in the RIT1 gene that is a close RAS paralog. However, relative to RAS subfamily members KRAS, NRAS, and HRAS, our characterization of RIT1 oncogenic properties remains incomplete. Therefore, further investigation on RIT1 will facilitate future development of targeted therapies. Our bioinformatic analysis revealed that RIT1 alterations in lung cancer predicted poor survivals but differed from its RAS paralogs by showing largely amplification and mutation. Through biochemical characterization of RIT1 hotspot mutations, we propose that RIT1 alterations were associated with increased protein abundance that promoted cell growth. Transcriptomic profiling indicated that oncogenic RIT1 mutant expression influenced common tumorigenic RAS/MAPK, PI3K/AKT, and E2F1 pathways, in addition to altered NFE2L2 target expression. Importantly, RIT1 mutants markedly sensitized cells to ferroptosis induction, and RIT1 knockdown suppressed ferroptotic cell death. Lung adenocarcinoma NCI-H2110 cells containing endogenous RIT1 M90I mutation were susceptible to ferroptosis induction both in vitro and in vivo within xenograft models. Hence, our study unravels a novel aspect of RIT1 mutations in lung cancer and suggests ferroptosis induction as a potential therapeutic strategy to treat lung cancer patients carrying RIT1 mutations.

Cyclic GMP/AMP (cGAMP) synthase (cGAS), along with the endoplasmic reticulum (ER)-associated stimulator of interferon genes (STING), are crucial elements of the type 1 interferon response. cGAS senses microbial DNA and self-DNA, labeling cGAS-STING as a crucial mechanism in autoimmunity, sterile inflammatory responses, and cellular senescence. However, chronic and aberrant activation of the cGAS-STING axis results in inflammatory and autoimmune diseases. cGAS-STING has emerged as a vital mechanism driving inflammation-related diseases, including lung diseases. Insights into the biology of the cGAS-STING pathway have enabled the discovery of small-molecule agents which have the potential to inhibit the cGAS-STING axis in lung diseases. In this review, we first outline the principal components of the cGAS-STING signaling cascade. Then, we discuss recent research that highlights general mechanisms by which cGAS-STING contributes to lung diseases. Then, we focus on summarizing a list of bioactive small-molecule compounds which inhibit the cGAS-STING pathway, reviewing their potential mechanisms.These review highlights a novel groundbreaking therapeutic possibilities through targeting cGAS-STING in lung diseases.