Molecular mechanism for recognition of the cargo adapter Rab6GTP by the dynein adapter BicD2.

Rab6 is a key modulator of protein secretion. The dynein adapter Bicaudal D2 (BicD2) recruits the motors cytoplasmic dynein and kinesin-1 to Rab6GTP-positive vesicles for transport; however, it is unknown how BicD2 recognizes Rab6. Here, we establish a structural model for recognition of Rab6GTP by BicD2, using structure prediction and mutagenesis. The binding site of BicD2 spans two regions of Rab6 that undergo structural changes upon the transition from the GDP- to GTP-bound state, and several hydrophobic interface residues are rearranged, explaining the increased affinity of the active GTP-bound state. Mutations of Rab6GTP that abolish binding to BicD2 also result in reduced co-migration of Rab6GTP/BicD2 in cells, validating our model. These mutations also severely diminished the motility of Rab6-positive vesicles in cells, highlighting the importance of the Rab6GTP/BicD2 interaction for overall motility of the multi-motor complex that contains both kinesin-1 and dynein. Our results provide insights into trafficking of secretory and Golgi-derived vesicles and will help devise therapies for diseases caused by BicD2 mutations, which selectively affect the affinity to Rab6 and other cargoes.

A Structural Model for the Core Nup358-BicD2 Interface.

Dynein motors facilitate the majority of minus-end-directed transport events on microtubules. The dynein adaptor Bicaudal D2 (BicD2) recruits the dynein machinery to several cellular cargo for transport, including Nup358, which facilitates a nuclear positioning pathway that is essential for the differentiation of distinct brain progenitor cells. Previously, we showed that Nup358 forms a "cargo recognition α-helix" upon binding to BicD2; however, the specifics of the BicD2-Nup358 interface are still not well understood. Here, we used AlphaFold2, complemented by two additional docking programs (HADDOCK and ClusPro) as well as mutagenesis, to show that the Nup358 cargo-recognition α-helix binds to BicD2 between residues 747 and 774 in an anti-parallel manner, forming a helical bundle. We identified two intermolecular salt bridges that are important to stabilize the interface. In addition, we uncovered a secondary interface mediated by an intrinsically disordered region of Nup358 that is directly N-terminal to the cargo-recognition α-helix and binds to BicD2 between residues 774 and 800. This is the same BicD2 domain that binds to the competing cargo adapter Rab6, which is important for the transport of Golgi-derived and secretory vesicles. Our results establish a structural basis for cargo recognition and selection by the dynein adapter BicD2, which facilitates transport pathways that are important for brain development.

Homogeneous, Simple, and Direct Analysis of Exosomal PD-L1 via Aptamer-Bivalent-Cholesterol-Anchor Assembly of DNAzyme (ABCzyme) for Tumor Immunotherapy.

Breakthroughs in immune checkpoint inhibitor (ICI) therapy have revolutionized clinical tumor therapy. Immunohistochemistry (IHC) analysis of PD-L1 in tumor tissue has been used to predict the response to tumor immunotherapy, but the results are not reproducible, and IHC is invasive and cannot be used to monitor the dynamic changes in PD-L1 expression during treatment. Monitoring the expression level of the PD-L1 protein on exosomes (exosomal PD-L1) is promising for both tumor diagnosis and tumor immunotherapy. Here, we established an aptamer-bivalent-cholesterol-anchor assembly of DNAzyme (ABCzyme) analytical strategy that can directly detect exosomal PD-L1 with a minimum lower limit of detection of 5.21 pg/mL. In this way, we found that the levels of exosomal PD-L1 are significantly elevated in the peripheral blood of patients with progressive disease. The precise analysis of exosomal PD-L1 by the proposed ABCzyme strategy provides a potentially convenient method for the dynamic monitoring of tumor progression in patients who receive immunotherapy and proves to be a potential and effective liquid biopsy method for tumor immunotherapy.

Role of Nesprin-2 and RanBP2 in BICD2-associated brain developmental disorders.

Bicaudal D2 (BICD2) is responsible for recruiting cytoplasmic dynein to diverse forms of subcellular cargo for their intracellular transport. Mutations in the human BICD2 gene have been found to cause an autosomal dominant form of spinal muscular atrophy (SMA-LED2), and brain developmental defects. Whether and how the latter mutations are related to roles we and others have identified for BICD2 in brain development remains little understood. BICD2 interacts with the nucleoporin RanBP2 to recruit dynein to the nuclear envelope (NE) of Radial Glial Progenitor cells (RGPs) to mediate their well-known but mysterious cell-cycle-regulated interkinetic nuclear migration (INM) behavior, and their subsequent differentiation to form cortical neurons. We more recently found that BICD2 also mediates NE dynein recruitment in migrating post-mitotic neurons, though via a different interactor, Nesprin-2. Here, we report that Nesprin-2 and RanBP2 compete for BICD2-binding in vitro. To test the physiological implications of this behavior, we examined the effects of known BICD2 mutations using in vitro biochemical and in vivo electroporation-mediated brain developmental assays. We find a clear relationship between the ability of BICD2 to bind RanBP2 vs. Nesprin-2 in controlling of nuclear migration and neuronal migration behavior. We propose that mutually exclusive RanBP2-BICD2 vs. Nesprin-2-BICD2 interactions at the NE play successive, critical roles in INM behavior in RGPs and in post-mitotic neuronal migration and errors in these processes contribute to specific human brain malformations.

Optimization of Laser-MAG Hybrid Welding Parameters of Ship Steel Based on Response Surface Methodology.

In this paper, the optimization of laser-MAG hybrid welding parameters of 10CrNi3MoV ship steel was developed. Using the Box-Behnken Design (BBD) model in Response Surface Methodology (RSM) and taking laser power, welding speed and welding current as response factors, the design matrix was completed and verified by experiment. The regression model associated with welding parameters was established by measuring the response indices, such as penetration, tensile strength and impact absorption energy. Through the model check, it was found that the accuracy of penetration and tensile strength of the model was high, and the optimized parameters were as follows: laser power (P) = 3700 W, welding speed (V) = 0.8 m/min, wire feeding speed (Vs) = 7 m/min. On the premise of meeting mechanical performance inspection standards, the maximum penetration was 8 mm.

Coil-to-α-helix transition at the Nup358-BicD2 interface activates BicD2 for dynein recruitment.

Nup358, a protein of the nuclear pore complex, facilitates a nuclear positioning pathway that is essential for many biological processes, including neuromuscular and brain development. Nup358 interacts with the dynein adaptor Bicaudal D2 (BicD2), which in turn recruits the dynein machinery to position the nucleus. However, the molecular mechanisms of the Nup358/BicD2 interaction and the activation of transport remain poorly understood. Here for the first time, we show that a minimal Nup358 domain activates dynein/dynactin/BicD2 for processive motility on microtubules. Using nuclear magnetic resonance titration and chemical exchange saturation transfer, mutagenesis, and circular dichroism spectroscopy, a Nup358 α-helix encompassing residues 2162-2184 was identified, which transitioned from a random coil to an α-helical conformation upon BicD2 binding and formed the core of the Nup358-BicD2 interface. Mutations in this region of Nup358 decreased the Nup358/BicD2 interaction, resulting in decreased dynein recruitment and impaired motility. BicD2 thus recognizes Nup358 through a 'cargo recognition α-helix,' a structural feature that may stabilize BicD2 in its activated state and promote processive dynein motility.

ABHD5 inhibits YAP-induced c-Met overexpression and colon cancer cell stemness via suppressing YAP methylation.

Cancer stemness represents a major source of development and progression of colorectal cancer (CRC). c-Met critically contributes to CRC stemness, but how c-Met is activated in CRC remains elusive. We previously identified the lipolytic factor ABHD5 as an important tumour suppressor gene in CRC. Here, we show that loss of ABHD5 promotes c-Met activation to sustain CRC stemness in a non-canonical manner. Mechanistically, we demonstrate that ABHD5 interacts in the cytoplasm with the core subunit of the SET1A methyltransferase complex, DPY30, thereby inhibiting the nuclear translocation of DPY30 and activity of SET1A. In the absence of ABHD5, DPY30 translocates to the nucleus and supports SET1A-mediated methylation of YAP and histone H3, which sequesters YAP in the nucleus and increases chromatin accessibility to synergistically promote YAP-induced transcription of c-Met, thus promoting the stemness of CRC cells. This study reveals a novel role of ABHD5 in regulating histone/non-histone methylation and CRC stemness.

TERT Genetic Mutations as Prognostic Marker in Glioma.

Telomerase reverse transcriptase (TERT) encodes the catalytic subunit of telomerase. The role of TERT in gliomagenesis has been extensively investigated. Since the influence of district, population, sample size, and experimental technology, our analysis, based on published articles, was aimed to obtain an accurate estimation of the relationship between TERT mutations and prognosis of glioma patients. PubMed, Web of science and Google Scholar databases were searched for potential articles. Finally, six studies with 2111 patients were included in the meta-analysis. Heterogeneity was evaluated by I2 statistics and P value. I2 > 50 % and P < 0.05 indicated significant heterogeneity between included studies and random-effects model was used; otherwise, fixed-effects model was used for analysis. The results of meta-analysis was expressed as hazard ratio (HR) and 95 % confidence interval (CI). The pooled results calculated by fixed-effects model suggested that TERT mutations were associated with poor prognosis of glioma patients (HR 1.68, 95 % CI 1.43-1.97). In conclusion, TERT mutations may be associated with shorter survival of glioma patients.

Mitogen-Activated Protein Kinase Kinase 4 Gene Polymorphism and Cancer Risk.

A number of epidemiological studies have assessed the association of -1304T > G polymorphism in the MKK4 gene and risk of cancer, but the results lack of statistical power due to the limited subjects used in these studies. This study was devised to identify the genetic effects of the -1304T > G polymorphism on cancer risk in a large meta-analysis.Eligible studies were identified by searching both Chinese and English databases. General as well as subgroup analyses were performed for 8 independent case-control publications with a total of 4623 cases and 5256 cancer-free controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association.Overall, this meta-analysis showed that the association between the -1304T > G polymorphism and cancer risk was statistically significant (GG vs TT: OR = 0.63, 95% CI, 0.52-0.75; GG + TG vs TT: OR = 0.85, 95% CI, 0.79-0.91; GG vs TG + TT: OR = 0.67, 95% CI, 0.56-0.80; G vs T: OR = 0.82, 95% CI, 0.77-0.88; TG vs TT: OR = 0.86, 95% CI, 0.79-0.93).Our meta-analysis reveals that the presence of the -1304T > G polymorphism is likely to decrease risk of cancer. Future larger studies are necessary to validate the current finding.

PSCA rs2294008 Polymorphism with Increased Risk of Cancer.

BACKGROUND: Published data on the association between PSCA rs2294008 polymorphism and cancer risk have implicated inconclusive results. To determine the relationship and to precisely assess the effect size estimate of the association, we performed a meta-analysis. METHODS: We searched published literature in Embase and PubMed databases using the search terms "PSCA", "prostate stem cell antigen", "variants", "polymorphism", "polymorphisms", and "cancer". A total of 21 eligible articles were retrieved, with 27, 197 cancer cases and 48, 237 controls. RESULTS: On the whole, we found the association between PSCA rs2294008 polymorphism and cancer risk was statistically significant: TT vs CC: OR = 1.18, 95% CI, 1.10 to 1.27; TT + CT vs CC: OR = 1.08, 95% CI, 1.05 to 1.10; TT vs CT + CC: OR = 1.14, 95% CI, 1.07 to 1.21; T vs C: OR = 1.10, 95% CI, 1.06 to 1.14; CT vs CC: OR = 1.10, 95% CI, 1.06 to 1.13. Stratified analyses in cancer type and ethnicity showed similar results. CONCLUSIONS: Based on the statistical evidence, we can draw a conclusion that the rs2294008 polymorphism of PSCA gene is likely to play a role in cancer carcinogenesis, especially in gastric cancer and bladder cancer.

High IGF2 expression is associated with poor clinical outcome in human ovarian cancer.

Ovarian cancer is one of the most common types of cancer in females and is the leading cause of death among gynaecological cancers in women worldwide. In the present study, we identified insulin-like growth factor 2 (IGF2) as a differentially expressed gene between cancerous and non-cancerous ovarian tissues. IGF2 was frequently increased in the human ovarian cancers when compared to the frequency in the non-cancerous ovarian tissues both at the mRNA (30/35) and protein level (61/72). The mean level of IGF2 in the tumor tissues was markedly higher than that in the non-cancerous tissues (nearly 3-fold change) (P=0.000). There was a significant correlation of IGF2 expression with histological grade (P=0.047). Kaplan-Meier analysis indicated that the ovarian cancer patients with high IGF2 expression showed a poorer prognosis both in regards to overall survival (OS) and progression-free survival (PFS) (n=1,648, P=0.000). Further analysis revealed that high expression of IGF2 was an unfavorable factor for the prognosis of the ovarian cancer patients at clinical stage I + II, stage III, histological grade 2, grade 3 or those treated with chemotherapy containing platin and Taxol. Our data provide evidence that IGF2 expression is frequently increased in ovarian cancer tissues, and high expression of IGF2 may be a significant prognostic factor for poor survival in ovarian cancer patients.

Discovery of the migrasome, an organelle mediating release of cytoplasmic contents during cell migration.

Cells communicate with each other through secreting and releasing proteins and vesicles. Many cells can migrate. In this study, we report the discovery of migracytosis, a cell migration-dependent mechanism for releasing cellular contents, and migrasomes, the vesicular structures that mediate migracytosis. As migrating cells move, they leave long tubular strands, called retraction fibers, behind them. Large vesicles, which contain numerous smaller vesicles, grow on the tips and intersections of retraction fibers. These fibers, which connect the vesicles with the main cell body, eventually break, and the vesicles are released into the extracellular space or directly taken up by surrounding cells. Since the formation of these vesicles is migration-dependent, we named them "migrasomes". We also found that cytosolic contents can be transported into migrasomes and released from the cell through migrasomes. We named this migration-dependent release mechanism "migracytosis".

Distinct role of CD86 polymorphisms (rs1129055, rs17281995) in risk of cancer: evidence from a meta-analysis.

BACKGROUND AND PURPOSE: Previous studies concerning the role of CD86 polymorphisms (rs1129055 and rs17281995) in cancer fail to provide compelling evidence. The aim of this study was to investigate the role of common polymorphisms in the risk of cancer by meta-analysis. METHODS: By using the search terms Cluster of Differentiation 86/CD86/B7-2/polymorphism/polymorphisms/cancer, we searched PubMed, Embase, CNKI, and Wanfang and identified four studies for rs1129055 (2137 subjects) and rs17281995 (2856 subjects) respectively. Cancer risk was estimated by odds ratio (OR) and 95% confidence interval (95% CI). MAJOR FINDINGS: Overall, we observed significant reduced risk of cancer in relation to rs1129055. Compared with the individuals with AA genotype, the individuals with GG genotype appeared to have 62% decreased risk to develop cancer (GG versus AA: OR, 0.62; 95% CI, 0.49-0.79; P(het)., 0.996). Similar effects were indicated in the G versus A allele model and the GG versus GA+AA genetic model (OR, 0.83; 95% CI, 0.74-0.93; P(het)., 0.987; OR, 0.63; 95% CI, 0.50-0.79; P(het)., 0.973). In addition, we found genotypes of rs17281995 had a major effect on overall cancer risk (CC versus GG: OR, 2.38; 95% CI, 1.43-3.95; P(het)., 0.433; C versus G: OR, 1.23; 95% CI, 1.06-1.43; P(het)., 0.521; CC versus GC+GG: OR, 2.38; 95% CI, 1.45-3.93; P(het)., 0.443). The association was also observed in Caucasians and colorectal cancer. No obvious publication bias was detected in this meta-analysis. CONCLUSIONS: These data reveal that rs1129055 may have protective effects on cancer risk in Asians and that rs17281995 is likely to contribute to risk of cancer, particularly colorectal cancer in Caucasians.

Multimodal therapy for adult Wilms' tumour: an experience from one centre.

INTRODUCTION: Wilms' tumour (WT) is very rare in adults but very common in children. Treatment guidelines for adult patients with WT are still insufficient. Some study groups recommend that therapeutic protocols for adults with WT (AWT) should follow the guidelines that have been established for children. OBJECTIVE: To describe the clinical and pathological characteristics of AWT as well as the treatment protocols and outcomes for AWT at our treatment centre. MATERIAL AND METHODS: Seven patients (5 females and 2 males) were diagnosed with AWT in our hospital between 2002 and 2009. The tumours were staged and the patients were treated according to the paediatric regimen recommended by the National Wilms' Tumor Study Group. RESULTS: The median patient age at the time of diagnosis was 29 years (range, 16-37 years). Flank pain was the most common clinical presentation. One patient was in Stage I of disease development, two were in Stage II, two were in Stage III and two were in Stage IV. Anaplasia was present in 3 patients with Stage III or Stage IV disease. All of the patients but one underwent nephrectomy and 2 incomplete surgeries were performed. Seven patients received 2-drug or 3-drug chemotherapy (dactinomycin and vincristine and/or doxorubicin). Two patients with Stage III disease also received radiation therapy (a total dose of 3600 or 3960 cGy). Complete remission was achieved in 4 patients. Three patients (one with Stage III disease, 2 patients with Stage IV disease) died of their disease and those patients were all classified with an unfavourable histological type called anaplasia. With a median follow-up of 53.5 months (range, 40-102 months), the 3-year and 5-year overall survival rates were 57.1% (95% confidence interval, 20.4-93.8%). CONCLUSIONS: The results of this report suggest that histological anaplasia might be an adverse prognostic factor for AWT. Proper application of the diagnostic and therapeutic regimens established for children may improve the prognosis of adult patients with WT.

Phosphorylated insulin-like growth factor 1 receptor is implicated in resistance to the cytostatic effect of gefitinib in colorectal cancer cells.

INTRODUCTION: The ability of certain cancer cells to maintain signaling via the phosphoinositide-3-kinase/Akt and/or Ras/mitogen-activated protein kinase (MAPK) pathways has been repeatedly involved in resistance to epidermal growth factor receptor (EGFR) inhibition. DISCUSSION: We investigated the potential mechanisms of the uncoupling of EGFR from its downstream signals in colorectal cancer (CRC) cells. Alternative growth factor receptors and regulation of downstream pathways in different gefitinib-responsive cell lines were determined. Basal insulin-like growth factor receptor-1ß (IGFR-1ß) phosphorylation was undetectable or present at very low levels in highly gefitinib-responsive cell lines and was present at strikingly high levels in less responsive cell lines. Further analysis of cell lines representing the most sensitive (Lovo), moderately sensitive (HT29), and most resistant (HCT116) strains was treated with an IGFR-1 inhibitor (AG1024), gefitinib, or both, revealing that elevated IGFR-1ß phosphorylation can compensate for the loss of EGFR signaling function. Increased insulin-like growth factor II expression induced by gefitinib or heterodimerization of EGFR and IGFR-1ß may trigger IGFR-1ß signal transduction via activation of Akt and MAPK. In addition, high levels of EGFR and IGFR-1ß phosphorylation were detected in CRC tumor tissue. We also showed that gefitinib- and/or AG1024-induced cytostatic effects could be mediated by glycogen synthase kinase-3ß (GSK-3ß) activation. Our data suggest that the crosstalk between EGFR and IGFR-1ß signaling are likely to contribute to resistance of CRC cells to gefitinib and that measurement of GSK-3ß activation may present a potential biomarker for evaluating the antitumor efficacy of receptor tyrosine kinase inhibition.