Secreted protease PRSS35 suppresses hepatocellular carcinoma by disabling CXCL2-mediated neutrophil extracellular traps.

Hepatocytes function largely through the secretion of proteins that regulate cell proliferation, metabolism, and intercellular communications. During the progression of hepatocellular carcinoma (HCC), the hepatocyte secretome changes dynamically as both a consequence and a causative factor in tumorigenesis, although the full scope of secreted protein function in this process remains unclear. Here, we show that the secreted pseudo serine protease PRSS35 functions as a tumor suppressor in HCC. Mechanistically, we demonstrate that active PRSS35 is processed via cleavage by proprotein convertases. Active PRSS35 then suppresses protein levels of CXCL2 through targeted cleavage of tandem lysine (KK) recognition motif. Consequently, CXCL2 degradation attenuates neutrophil recruitment to tumors and formation of neutrophil extracellular traps, ultimately suppressing HCC progression. These findings expand our understanding of the hepatocyte secretome's role in cancer development while providing a basis for the clinical translation of PRRS35 as a therapeutic target or diagnostic biomarker.

Non-canonical phosphoglycerate dehydrogenase activity promotes liver cancer growth via mitochondrial translation and respiratory metabolism.

Phosphoglycerate dehydrogenase (PHGDH) is a key serine biosynthesis enzyme whose aberrant expression promotes various types of tumors. Recently, PHGDH has been found to have some non-canonical functions beyond serine biosynthesis, but its specific mechanisms in tumorigenesis remain unclear. Here, we show that PHGDH localizes to the inner mitochondrial membrane and promotes the translation of mitochondrial DNA (mtDNA)-encoded proteins in liver cancer cells. Mechanistically, we demonstrate that mitochondrial PHGDH directly interacts with adenine nucleotide translocase 2 (ANT2) and then recruits mitochondrial elongation factor G2 (mtEFG2) to promote mitochondrial ribosome recycling efficiency, thereby promoting mtDNA-encoded protein expression and subsequent mitochondrial respiration. Moreover, we show that treatment with a mitochondrial translation inhibitor or depletion of mtEFG2 diminishes PHGDH-mediated tumor growth. Collectively, our findings uncover a previously unappreciated function of PHGDH in tumorigenesis acting via promotion of mitochondrial translation and bioenergetics.

Metagenomics Reveals Dominant Unusual Sulfur Oxidizers Inhabiting Active Hydrothermal Chimneys From the Southwest Indian Ridge.

The deep-sea hydrothermal vents (DSHVs) in the Southwest Indian Ridge (SWIR) are formed by specific geological settings. However, the community structure and ecological function of the microbial inhabitants on the sulfide chimneys of active hydrothermal vents remain largely unknown. In this study, our analyses of 16S rRNA gene amplicons and 16S rRNA metagenomic reads showed the dominance of sulfur-oxidizing Ectothiorhodospiraceae, Thiomicrorhabdus, Sulfurimonas, and Sulfurovum on the wall of two active hydrothermal chimneys. Compared with the inactive hydrothermal sediments of SWIR, the active hydrothermal chimneys lacked sulfur-reducing bacteria. The metabolic potentials of the retrieved 82 metagenome-assembled genomes (MAGs) suggest that sulfur oxidation might be conducted by Thiohalomonadales (classified as Ectothiorhodospiraceae based on 16S rRNA gene amplicons), Sulfurovaceae, Hyphomicrobiaceae, Thiotrichaceae, Thiomicrospiraceae, and Rhodobacteraceae. For CO2 fixation, the Calvin-Benson-Bassham and reductive TCA pathways were employed by these bacteria. In Thiohalomonadales MAGs, we revealed putative phytochrome, carotenoid precursor, and squalene synthesis pathways, indicating a possible capacity of Thiohalomonadales in adaptation to dynamics redox conditions and the utilization of red light from the hot hydrothermal chimneys for photolithotrophic growth. This study, therefore, reveals unique microbiomes and their genomic features in the active hydrothermal chimneys of SWIR, which casts light on ecosystem establishment and development in hydrothermal fields and the deep biosphere.

[Overexpression of LncRNA ITGB2-AS1 Predicts Adverse Prognosis in Acute Myeloid Leukemia].

OBJECTIVE: LncRNA ITGB2-AS1 has been found to play important roles in the occurrence and development of human solid tumors. However, its role in hematological diseases, especially acute myeloid leukemia (AML), remains unclear. The aim of this study was to identify the expression pattern of ITGB2-AS1 in AML patients and to further explore its clinical significance. METHODS: ITGB2-AS1 expression was analyzed in public datasets (including TCGA and GSE63270) and further validated in a cohort of 109 AML patients by real-time quantitative PCR (RT-qPCR). RESULTS: The level of ITGB2-AS1 was up-regulated among two independent cohorts (TCGA, P<0.05; GSE63270, P<0.05), which was confirmed by the data from 109 AML patients enrolled in this study (P<0.05). Clinically, high ITGB2-AS1 expression was associated with older age (P=0.023) and lower complete remission (CR) rate (P=0.005). Multivariate analysis identified that high ITGB2-AS1 expression was an independent prognostic factor not only for CR rate (P=0.027) but also for overall survival (OS) time (P=0.011), and ITGB2-AS1 was positively correlated with ITGB2 expression in both TCGA (r=0.74, P<0.001) and clinical data detected in this study (r=0.881, P<0.001). High ITGB2 expression was also associated with older age (P=0.02) and lower CR rate (P=0.020). Moreover, high ITGB2 expression predicted worse OS (P=0.028). CONCLUSION: ITGB2-AS1 is overexpressed in AML and predicts poor prognosis in AML patients.

MYC promotes cancer progression by modulating m6 A modifications to suppress target gene translation.

The MYC oncoprotein activates and represses gene expression in a transcription-dependent or transcription-independent manner. Modification of mRNA emerges as a key gene expression regulatory nexus. We sought to determine whether MYC alters mRNA modifications and report here that MYC promotes cancer progression by down-regulating N6-methyladenosine (m6 A) preferentially in transcripts of a subset of MYC-repressed genes (MRGs). We find that MYC activates the expression of ALKBH5 and reduces m6 A levels in the mRNA of the selected MRGs SPI1 and PHF12. We also show that MYC-regulated m6 A controls the translation of MRG mRNA via the specific m6 A reader YTHDF3. Finally, we find that inhibition of ALKBH5, or overexpression of SPI1 or PHF12, effectively suppresses the growth of MYC-deregulated B-cell lymphomas, both in vitro and in vivo. Our findings uncover a novel mechanism by which MYC suppresses gene expression by altering m6 A modifications in selected MRG transcripts promotes cancer progression.

The High mortality and antimicrobial resistance of Klebsiella pneumoniae bacteremia in northern Taiwan.

INTRODUCTION: Klebsiella pneumoniae, a common hospital- and community-acquired pathogen, is notorious for multidrug resistance. This study aimed to better understand the correlation of clinical presentation and microbiological characteristics of the isolates causing bloodstream infections (BSIs) in Taiwan. METHODOLOGY: We retrospectively collected 150 isolates derived from K. pneumoniae bacteremia patients in Taiwan in both 2014 and 2016. Clinical data, bacterial serotyping and drug susceptibility tests were comparatively analyzed. RESULTS: Demographic data showed that diabetes mellitus (DM) was the most common underlying disease (44.0%). The overall 30-day mortality rate was 19.3%, and higher mortality was found in patients with malignancy than others (P = 0.023). Serotype distribution was diverse. The major isolates belonged to non-PCR-typeable serotypes (58.7%) associated with hospital-acquired infections (P = 0.007) and in non-DM patients (P < 0.001), while K2 and K20 significantly caused infections and in DM patients (P = 0.046 and P = 0.006, respectively); however, only K2 showed more community-acquired infection (P = 0.022) than other typeable serotypes. Resistance to antibiotics in clinical isolates in the year 2016 was > 24%, including cefazolin (54%), ampicillin-sulbactam (25%) and cefuroxime (25%). Susceptibility to gentamicin, flomoxef, and tigecycline reduced between the two time periods (2014 and 2016). However, the isolates remained highly susceptible to amikacin and ertapenem (> 95%). CONCLUSIONS: Patients with cancer had a higher 30-day mortality rate than others. Amikacin and ertapenem are the drugs of choice for the treatment of multidrug-resistant K. pneumoniae BSIs in Taiwan.

Tumor necrosis factor receptor-associated factor 3 from Anodonta woodiana is an important factor in bivalve immune response to pathogen infection.

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a multifunctional adaptor protein in innate and acquired immune system that plays a key role in the regulation of the RIG-I-like receptor (RLR) and Toll-like receptor (TLR) signaling pathway in mammals. However, the immune function of TRAF3 homologs in freshwater mollusks is not well understood. In this study, we identified a bivalve TRAF3 gene (AwTRAF3) from Anodonta woodiana and investigated its potential roles during immune challenges. The present AwTRAF3 encoded a polypeptide of 562 amino acids with predicted molecular mass of 64.5 kDa and PI of 7.9. Similar to other reported TRAF3s, AwTRAF3 contained a RING finger domain, two TRAF domains with zinc finger domains, a coiled coli region and a conserved C-terminal meprin and TRAF homology (MATH) domain. Quantitative real-time PCR (qRT-PCR) analysis revealed that AwTRAF3 mRNA was broadly expressed in all of the examined tissues, with high expression in hepatopancreas, gill and heart. In addition, immune challenge experiments directly showed that transcript levels of AwTRAF3 in hepatopancreas were significantly regulated upon bacterial (Vibrio alginolyticus and Staphylococcus aureus) and viral (poly (I:C)) challenges, respectively. Moreover, GFP-tagged AwTRAF3 fusion protein was found to be located primarily in the cytoplasm in HEK293T cells. Altogether, these data provided the first experimental demonstration that freshwater mollusks possess a functional TRAF3 that was involved in the innate defense against bacterial and viral infection.

A molluscan TNF receptor-associated factor 2 (TRAF2) was involved in host defense against immune challenges.

Tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) is a member of the TRAF superfamily that acted as a key signal transduction protein and has been implicated in inflammatory and apoptosis processes in mammals. However, identification of TRAF2s in invertebrates is very limited and its function, in particular that under immune challenges, is still unknown. In this report, a molluscan TRAF2 gene (referred to as AwTRAF2) was cloned and characterized from the freshwater bivalve, Anodonta woodiana. The open reading frame (ORF) of AwTRAF2 was 1683 bp in length, which encoded a putative 560 amino acid-protein. The deduced AwTRAF2 sequence shared similar structural characteristics and close evolutionary relationship with mollusk TRAF2s. The tissue-specific expression analysis revealed that AwTRAF2 mRNA was broadly expressed in all tested tissues, with high expression in gill and hepatopancreas. In addition, in vivo injection experiments directly showed that AwTRAF2 mRNA levels in hepatopancreas were significantly up-regulated in response to bacterial pathogen (Vibrio alginolyticus and Staphylococcus aureus) and PAMPs (Lipopolysaccharides and Peptidoglycan) challenges. Moreover, fluorescence microscopy observations revealed that AwTRAF2 was mainly located in cytoplasm of HEK293T cells and its overexpression significantly increased the transcriptional activities of the NF-κB-Luc reporter gene in HEK293T cells. Taken together, this study provided the experimental evidence of the presence of a functional TRAF2 in freshwater bivalves, which revealed its involvement in host response to immune challenges in A. woodiana.

Molecular identification and functional characterization of a tumor necrosis factor (TNF) gene in Crassostrea hongkongensis.

Tumor necrosis factor superfamily (TNFSF) represents a group of multifunctional inflammatory cytokines that have been shown to participate in a variety of pathological and immunological process. However, the functions of these proteins in oyster are still poorly understood. In the present study, an oyster TNF homolog (named ChTNF) was identified from a cDNA library of Crassostrea hongkongensis. The complete cDNA of ChTNF was 2457bp in length containing an open reading frame (ORF) of 1044bp, a 5'-untranslated region (UTR) of 381bp and a 3'-UTR of 1032bp. The deduced ChTNF protein consisted of 347 amino acids with a characteristic transmembrane domain and a typical TNF homology domain (THD). Quantitative real-time PCR analysis revealed that ChTNF was broadly expressed in various oyster tissues and different stages of embryonic development. In addition, transcriptional analysis indicated that ChTNF transcription levels in hemocytes were increased significantly in pathogen challenge groups (Vibrio alginolyticus and Staphylococcus haemolyticus) compared to that in the control. Moreover, in vitro PAMP (lipopolysaccharide and peptidoglycan) treatments showed a stimulatory effect on the expression of ChTNF in the primary cultured hemocytes of C. hongkongensis. Finally, dual-luciferase reporter assays revealed that ChTNF could activate the NF-κB-Luc reporter in a dose-dependent manner in HEK293T cells. Altogether, these findings may provide valuable information regarding oyster TNFs and its role in innate immunity.

A molluscan extracellular signal-regulated kinase is involved in host response to immune challenges in vivo and in vitro.

Extracellular signal-regulated kinases (ERKs) are a group of highly conserved serine/threonine-specific protein kinases that function as important signaling intermediates in mitogen-activated protein kinase (MAPK) pathways, which are involved in a wide variety of cellular activities, including proliferation, inflammation and cytokine production. However, little is known about the roles of this kinase in mollusk immunity. In this study, we identified a molluscan ERK homolog (ChERK) in the Hong Kong oyster (Crassostrea hongkongensis) and investigated its biological functions. The open reading frame (ORF) of ChERK encoded a polypeptide of 365 amino acids, with a predicted molecular weight of 41.96 kDa and pI of 6.43. The predicted ChERK protein contained typical characteristic motifs of the ERK family, including a dual threonine-glutamate-tyrosine (TEY) phosphorylation motif and an ATRW substrate binding site. Phylogenetic analysis revealed that ChERK belonged to the mollusk cluster and shared a close evolutionary relationship with ERK from Crassostrea gigas. In addition, quantitative real-time PCR analysis revealed that ChERK expression was detected in all of the examined tissues and stages of embryonic development; its transcript level was significantly induced upon challenge with bacterial pathogens (Vibrio alginolyticus and Staphylococcus haemolyticus) in vivo and PAMPs (lipopolysaccharide and peptidoglycan) in vitro. Moreover, ChERK was mainly located in the cytoplasm of HEK293T cells. Taken together, these findings may provide novel insights into the functions of molluscan ERKs, especially their roles in response to immune challenge in oyster.