Interaction of serologically defined colon cancer antigen-3 with Arf6 and its predominant expression in the mouse testis

Endosome associated trafficking regulator 1 promotes tumor growth and invasion of glioblastoma multiforme via inhibiting TNF signaling pathway

PURPOSE

Endosome associated trafficking regulator 1 (ENTR1) is a novel endosomal protein, which can affect multiple cellular biological behavior by remodeling plasma membrane structures. However, little is known regarding its function and underlying mechanisms in glioblastoma multiforme.

METHODS

Expression profile and clinical signature were obtained from The Public Database of human tumor. Immunohistochemical staining and western blotting assays were used to measure ENTR1 expression level. Human primary GBM tumor cells and human GBM cell lines A172, U87 and U251 were used to clarify the precise role of ENTR1. CCK-8 assays, wound healing and transwell invasion assays were designed to investigate cell viability, invasion and migration of GBM cells, respectively. Underlying molecular mechanisms of ENTR1 were determined via RNA-seq analysis. Tumor formation assay was used to validate the influence of ENTR1 in vivo.

RESULTS

Compared with normal brain tissues, ENTR1 was highly expressed in gliomas and correlated with malignant grades of gliomas and poor overall survival time. The proliferation and invasion of GBM cells could be weaken and the sensitivity to temozolomide (TMZ) chemotherapy increased after knocking down ENTR1. Overexpression of ENTR1 could reverse this effect. RNA-seq analysis showed that tumor necrosis factor (TNF) signaling pathway might be a putative regulatory target of ENTR1. Tumor formation assay validated that ENTR1 was a significant factor in tumor growth.

CONCLUSION

Our results indicated that ENTR1 played an important role in cell proliferation, invasion and chemotherapeutic sensitivity of GBM, suggesting that ENTR1 might be a novel prognostic marker and significant therapeutic target for GBM.

Regulation of anoikis by extrinsic death receptor pathways

Metastatic cancer cells can develop anoikis resistance in the absence of substrate attachment and survive to fight tumors. Anoikis is mediated by endogenous mitochondria-dependent and exogenous death receptor pathways, and studies have shown that caspase-8-dependent external pathways appear to be more important than the activity of the intrinsic pathways. This paper reviews the regulation of anoikis by external pathways mediated by death receptors. Different death receptors bind to different ligands to activate downstream caspases. The possible mechanisms of Fas-associated death domain (FADD) recruitment by Fas and TNF receptor 1 associated-death domain (TRADD) recruitment by tumor necrosis factor receptor 1 (TNFR1), and DR4- and DR5-associated FADD to induce downstream caspase activation and regulate anoikis were reviewed. This review highlights the possible mechanism of the death receptor pathway mediation of anoikis and provides new insights and research directions for studying tumor metastasis mechanisms. Video Abstract.

ARL9 is upregulated and serves as a biomarker for a poor prognosis in colon adenocarcinoma

BACKGROUND

ARL9 is a newly identified member of the ARF family, and the clinical significance of ARL9 in colon adenocarcinoma is unknown. In this study, we aimed to explore the expression of ARL9 mRNA in colon adenocarcinoma, and its effect on the prognosis of patients with colon adenocarcinoma.

METHODS

We investigated the differential expression of ARL9 between colon adenocarcinoma tissue and adjacent tissues through a bioinformatics analysis using The Cancer Genome Atlas (TCGA) database. The correlation between clinical characteristics and the mRNA expression level of ARL9 were analyzed. A survival analysis and a Cox regression analysis were used to determine the prognostic significance of ARL9. Finally, we conducted a gene set enrichment analysis (GSEA) to explore the ARL9 signaling pathways involved in the development of colon adenocarcinoma. The effect of the expression of ARL9 on the proliferation and migration of colon adenocarcinoma was analyzed by the CCK8 method and a cell scratch test, respectively.

RESULTS

The mRNA expression of ARL9 in colon adenocarcinoma tissues was higher in comparison to the level in normal adjacent tissues (P < 0.05). The mRNA expression of ARL9 was not related to sex, tumor stage, T stage, N stage, M stage, but to age. The 5-year survival rate of colon adenocarcinoma patients with high ARL9 mRNA expression levels was significantly lower than that of patients with low ARL9 mRNA expression levels (P < 0.05). Age and the high mRNA expression of ARL9 were independent risk factors for a poor prognosis in patients with colon adenocarcinoma. The GSEA suggested that ARL9 may be able to upregulate cell adhesion, extracellular matrix receptor interactions, tumor-associated pathways, and downregulate the citrate cycle and tricarboxylic acid cycle pathway, which are involved in the development of colon adenocarcinoma. After knocking down ARL9, the proliferation and migration abilities of colon adenocarcinoma cells were decreased (P < 0.01).

CONCLUSION

The mRNA expression of ARL9 is upregulated in colon adenocarcinoma, and higher mRNA expression levels are associated with a poor prognosis. Knocking down ARL9 can reduce the proliferation and migration of colon adenocarcinoma cells. ARL9 mRNA can be used as a prognostic biomarker in patients with colon adenocarcinoma.

ADP-ribosylation factor 6 expression increase in oesophageal adenocarcinoma suggests a potential biomarker role for it

ADP-ribosylation factor 6 small GTPase plays an important role in cell migration, invasion and angiogenesis, which are the hallmarks of cancer. Although alterations in ARF6 expression and activity have been linked to metastatic cancer in one or two tissues, the expression of ARF6 in cancers over a wide range of tissues has not been studied so far. In this report, we analysed the expression of ARF6 mRNA in cancers and corresponding healthy controls from 17 different tissues by real-time qualitative polymerase chain reaction (RT-qPCR). We further evaluated ARF6 protein expression in oesophageal adenocarcinoma (EAC) tissue microarray cores by immunohistochemistry. The ARF6 gene expression levels are highly variable between healthy and cancer tissues. Our findings suggest that the ARF6 gene expression is up-regulated highest in oesophageal cancer. In EAC TMAs, ARF6 protein expression increase correlated with EAC progression. This is the first study to investigate ARF6 gene expression in a wide array of cancer tissues and demonstrate that ARF6 expression, at both mRNA and protein levels, is significantly upregulated in higher grades of EAC, which may be useful in targeting ARF6 for cancer diagnostic and therapeutic purposes.

Genome-Wide Detection of Copy Number Variations and Their Association With Distinct Phenotypes in the World's Sheep

Copy number variations (CNVs) are a major source of structural variation in mammalian genomes. Here, we characterized the genome-wide CNV in 2059 sheep from 67 populations all over the world using the Ovine Infinium HD (600K) SNP BeadChip. We tested their associations with distinct phenotypic traits by conducting multiple independent genome-wide tests. In total, we detected 7547 unique CNVs and 18,152 CNV events in 1217 non-redundant CNV regions (CNVRs), covering 245 Mb (∼10%) of the whole sheep genome. We identified seven CNVRs with frequencies correlating to geographical origins and 107 CNVRs overlapping 53 known quantitative trait loci (QTLs). Gene ontology and pathway enrichment analyses of CNV-overlapping genes revealed their common involvement in energy metabolism, endocrine regulation, nervous system development, cell proliferation, immune, and reproduction. For the phenotypic traits, we detected significantly associated (adjusted P < 0.05) CNVRs harboring functional candidate genes, such as SBNO2 for polycerate; PPP1R11 and GABBR1 for tail weight; AKT1 for supernumerary nipple; CSRP1, WNT7B, HMX1, and FGFR3 for ear size; and NOS3 and FILIP1 in Wadi sheep; SNRPD3, KHDRBS2, and SDCCAG3 in Hu sheep; NOS3, BMP1, and SLC19A1 in Icelandic; CDK2 in Finnsheep; MICA in Romanov; and REEP4 in Texel sheep for litter size. These CNVs and associated genes are important markers for molecular breeding of sheep and other livestock species.

The Vps52 subunit of the GARP and EARP complexes is a novel Arf6-interacting protein that negatively regulates neurite outgrowth of hippocampal neurons

ADP ribosylation factor 6 (Arf6) is a small GTP-binding protein implicated in neuronal morphogenesis through endosomal trafficking and actin remodeling. In this study, we identified Vps52, a core subunit of the Golgi-associated retrograde protein (GARP) and endosome-associated recycling protein (EARP) complexes, as a novel Arf6-binding protein by yeast two-hybrid screening. Vps52 interacted specifically with GTP-bound Arf6 among the Arf family. Immunohistochemical analyses of hippocampal pyramidal cells revealed that fine punctate immunolabeling for Vps52 was distributed throughout neuronal compartments, most densely in the cell body and dendritic shafts, and was largely associated with trans-Golgi network and vesicular endomembranes. In cultured hippocampal neurons, knockdown of Vps52 increased total length of axons and dendrites; these phenotypes were completely restored by co-expression of shRNA-resistant full-length Vps52. However, co-expression of a Vps52 mutant lacking the ability to interact with Arf6 restored only the Vps52-knockdown phenotype of the dendritic length. The present findings suggest that Vps52 is a novel Arf6-interacting protein that regulates neurite outgrowth in hippocampal neurons.

Sdccag3 Promotes Implant Osseointegration during Experimental Hyperlipidemia

Hyperlipidemia adversely affects bone metabolism, often resulting in compromised osseointegration and implant loss. In addition, genetic networks associated with osseointegration have been proposed. Serologically defined colon cancer antigen 3 (Sdccag3) is a novel endosomal protein that functions in actin cytoskeleton remodeling, protein trafficking and secretion, cytokinesis, and apoptosis, but its roles in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and in implant osseointegration under hyperlipidemic conditions have not been uncovered. Here, we performed microarray and RNA sequencing analysis to determine the differential expression of the Sdccag3 gene and related noncoding RNAs (ncRNAs) and to assess the long noncoding RNA (lncRNA) MSTRG.97162.4-miR-193a-3p-Sdccag3 coexpression network in bone tissues within the region 0.5 mm around implants in hyperlipidemic rats. In this experiment, we found that Sdccag3 and the previously uncharacterized lncRNA-MSTRG.97162.4 were downregulated during hyperlipidemia, while miR-193a-3p was upregulated. Sdccag3 overexpression increased new trabecular formation, the bone volume/total volume (BV/TV) (1.24-fold), and bone-implant combination ratio (BIC%) (1.26-fold). An RNA pulldown experiment revealed that Sdccag3 protein targeted lncRNA-MSTRG.97162.4 nucleotides 361 to 389. In addition, lncRNA-MSTRG.97162.4 overexpression significantly enhanced Sdccag3 (2.78-fold) expression and increased BV/TV (1.45-fold) and BIC% (1.07-fold) at the bone-implant interface. Taken together, these findings indicate that Sdccag3 overexpression enhances implant osseointegration under hyperlipidemic conditions by binding to lncRNA-MSTRG.97162.4. Furthermore, miR-193a-3p overexpression inhibited lncRNA-MSTRG.97162.4 (0.63-fold) and Sdccag3 (0.88-fold) expression and induced poor implant osseointegration (BV/TV, 0.86-fold; BIC%, 0.82-fold), while miR-193a-3p downregulation produced the opposite results (lncRNA-MSTRG.97162.4, 10.69-fold; Sdccag3, 6.96-fold; BV/TV, 1.20-fold; BIC%, 1.26-fold). Therefore, our findings show that Sdccag3 promotes implant osseointegration, and its related lncRNA-MSTRG.97162.4 and miR-193a-3p play an important role in osseointegration during hyperlipidemia, which might be a promising therapeutic target for improving dental implantation success rates.

ADP Ribosylation Factor 6 Regulates Neuronal Migration in the Developing Cerebral Cortex through FIP3/Arfophilin-1-dependent Endosomal Trafficking of N-cadherin

During neural development, endosomal trafficking controls cell shape and motility through the polarized transport of membrane proteins related to cell–cell and cell–extracellular matrix interactions. ADP ribosylation factor 6 (Arf6) is a critical small GTPase that regulates membrane trafficking between the plasma membrane and endosomes. We herein demonstrated that the knockdown of endogenous Arf6 in mouse cerebral cortices led to impaired neuronal migration in the intermediate zone and cytoplasmic retention of N-cadherin and syntaxin12 in migrating neurons. Rescue experiments with separation-of-function Arf6 mutants identified Rab11 family-interacting protein 3 (FIP3)/Arfophilin-1, a dual effector for Arf6 and Rab11, as a downstream effector of Arf6 in migrating neurons. The knockdown of FIP3 led to impaired neuronal migration in the intermediate zone and cytoplasmic retention of N-cadherin in migrating neurons, similar to that of Arf6, which could be rescued by the coexpression of wild-type FIP3 but not FIP3 mutants lacking the binding site for Arf6 or Rab11. These results suggest that Arf6 regulates cortical neuronal migration in the intermediate zone through the FIP3-dependent endosomal trafficking.