Alterations in gut microbiota and bile acids by proton-pump inhibitor use and possible mediating effects on elevated glucose levels and insulin resistance.

Several observational studies have suggested that proton-pump inhibitor (PPI) use might increase diabetes risk, but the mechanism remains unclear. This study aimed to investigate the effects of PPI use on gut microbiota and bile acids (BAs) profiles, and to explore whether these changes could mediate the association of PPIs use with fasting blood glucose (FBG) levels and insulin resistance (IR) in Chinese population. A cross-sectional study was conducted in Shenzhen, China, from April to August 2021, enrolled 200 eligible patients from the local hospital. Participants completed a questionnaire and provided blood and stool samples. Gut microbiome was measured by16S rRNA gene sequencing, and bile acids were quantified by UPLC-MS/MS. Insulin resistance (IR) was assessed using the Homeostasis Model Assessment 2 (HOMA2-IR). PPI use was positively associated with higher levels of FBG and HOMA2-IR after controlling for possible confounders. PPI users exhibited a decreased Firmicutes and an increase in Bacteroidetes phylum, alongside higher levels of glycoursodeoxycholic acid (GUDCA) and taurochenodeoxycholic acid (TCDCA). Higher abundances of Bacteroidetes and Fusobacterium as well as higher levels of TCDCA in PPI users were positively associated with elevated FBG or HOMA2-IR. Mediation analyses indicated that the elevated levels of FBG and HOMA2-IR with PPI use were partially mediated by the alterations in gut microbiota and specific BAs (i.e., Fusobacterium genera and TCDCA). Long-term PPI use may increase FBG and HOMA2-IR levels, and alterations in gut microbiota and BAs profiles may partially explain this association.

Tyrosine phosphorylation-mediated YAP1-TFAP2A interactions coordinate transcription and trastuzumab resistance in HER2+ breast cancer.

Trastuzumab resistance in HER2+ breast cancer (BC) is the major reason leading to poor prognosis of BC patients. Oncogenic gene overexpression or aberrant activation of tyrosine kinase SRC is identified to be the key modulator of trastuzumab response. However, the detailed regulatory mechanisms underlying SRC activation-associated trastuzumab resistance remain poorly understood. In the present study, we discover that SRC-mediated YAP1 tyrosine phosphorylation facilitates its interaction with transcription factor AP-2 alpha (activating enhancer binding protein 2 alpha, TFAP2A), which in turn promotes YAP1/TEAD-TFAP2A (YTT) complex-associated transcriptional outputs, thereby conferring trastuzumab resistance in HER2+ BC. Inhibition of SRC kinase activity or disruption of YTT complex sensitizes cells to trastuzumab treatment in vitro and in vivo. Additionally, we also identify YTT complex co-occupies the regulatory regions of a series of genes related to trastuzumab resistance and directly regulates their transcriptions, including EGFR, HER2, H19 and CTGF. Moreover, YTT-mediated transcriptional regulation is coordinated by SRC kinase activity. Taken together, our study reveals that SRC-mediated YTT complex formation and transcriptions are responsible for multiple mechanisms associated with trastuzumab resistance. Therefore, targeting HER2 signaling in combination with the inhibition of YTT-associated transcriptional outputs could serve as the treatment strategy to overcome trastuzumab resistance caused by SRC activation.

Overexpression of ABCC1 and ABCG2 confers resistance to talazoparib, a poly (ADP-Ribose) polymerase inhibitor.

AIMS: The overexpression of ABC transporters on cancer cell membranes is one of the most common causes of multidrug resistance (MDR). This study investigates the impact of ABCC1 and ABCG2 on the resistance to talazoparib (BMN-673), a potent poly (ADP-ribose) polymerase (PARP) inhibitor, in ovarian cancer treatment. METHODS: The cell viability test was used to indicate the effect of talazoparib in different cell lines. Computational molecular docking analysis was conducted to simulate the interaction between talazoparib and ABCC1 or ABCG2. The mechanism of talazoparib resistance was investigated by constructing talazoparib-resistant subline A2780/T4 from A2780 through drug selection with gradually increasing talazoparib concentration. RESULTS: Talazoparib cytotoxicity decreased in drug-selected or gene-transfected cell lines overexpressing ABCC1 or ABCG2 but can be restored by ABCC1 or ABCG2 inhibitors. Talazoparib competitively inhibited substrate drug efflux activity of ABCC1 or ABCG2. Upregulated ABCC1 and ABCG2 protein expression on the plasma membrane of A2780/T4 cells enhances resistance to other substrate drugs, which could be overcome by the knockout of either gene. In vivo experiments confirmed the retention of drug-resistant characteristics in tumor xenograft mouse models. CONCLUSIONS: The therapeutic efficacy of talazoparib in cancer may be compromised by its susceptibility to MDR, which is attributed to its interactions with the ABCC1 or ABCG2 transporters. The overexpression of these transporters can potentially diminish the therapeutic impact of talazoparib in cancer treatment.

ABCB1-dependent collateral sensitivity of multidrug-resistant colorectal cancer cells to the survivin inhibitor MX106-4C.

AIMS: To investigate the collateral sensitivity (CS) of ABCB1-positive multidrug resistant (MDR) colorectal cancer cells to the survivin inhibitor MX106-4C and the mechanism. METHODS: Biochemical assays (MTT, ATPase, drug accumulation/efflux, Western blot, RT-qPCR, immunofluorescence, flow cytometry) and bioinformatic analyses (mRNA-sequencing, reversed-phase protein array) were performed to investigate the hypersensitivity of ABCB1 overexpressing colorectal cancer cells to MX106-4C and the mechanisms. Synergism assay, long-term selection, and 3D tumor spheroid test were used to evaluate the anti-cancer efficacy of MX106-4C. RESULTS: MX106-4C selectively killed ABCB1-positive colorectal cancer cells, which could be reversed by an ABCB1 inhibitor, knockout of ABCB1, or loss-of-function ABCB1 mutation, indicating an ABCB1 expression and function-dependent mechanism. MX106-4C's selective toxicity was associated with cell cycle arrest and apoptosis through ABCB1-dependent survivin inhibition and activation on caspases-3/7 as well as modulation on p21-CDK4/6-pRb pathway. MX106-4C had good selectivity against ABCB1-positive colorectal cancer cells and retained this in multicellular tumor spheroids. In addition, MX106-4C could exert a synergistic anti-cancer effect with doxorubicin or re-sensitize ABCB1-positive cancer cells to doxorubicin by reducing ABCB1 expression in the cell population via long-term exposure. CONCLUSIONS: MX106-4C selectively kills ABCB1-positive MDR colorectal cancer cells via a novel ABCB1-dependent survivin inhibition mechanism, providing a clue for designing CS compound as an alternative strategy to overcome ABCB1-mediated colorectal cancer MDR.

A Mitochondria-Targeted Nitric Oxide Probe for Multimodality Imaging of Macrophage Immune Responses.

Nitric oxide (NO) is a crucial signal molecule closely linked to the biological immune response, especially in macrophage polarization. When activated, macrophages enter a pro-inflammatory state and produce NO, a marker for the M1 phenotype. In contrast, the anti-inflammatory M2 phenotype does not produce NO. We developed a mitochondria-targeted two-photon iridium-based complex (Ir-ImNO) probe that can detect endogenous NO and monitor macrophages' different immune response states using various imaging techniques, such as one- and two-photon phosphorescence imaging and phosphorescence lifetime imaging. Ir-ImNO was used to monitor the immune activation of macrophages in mice. This technology aims to provide a clear and comprehensive visualization of macrophage immune responses.

Effects of serta and sertb knockout on aggression in zebrafish (Danio rerio).

Zebrafish (Danio rerio) are unusual in having two paralogues of the serotonin re-uptake transporter (Sert), slc6a4a (serta) and slc6a4b (sertb), the transporter that serves in serotonin re-uptake from a synapse into the pre-synaptic cell or in serotonin uptake from the extracellular milieu into cells in the peripheral tissues. To address a knowledge gap concerning the specific roles of these paralogues, we used CRISPR/Cas9 technology to generate zebrafish knockout lines predicted to lack functional expression of Serta or Sertb. The consequences of loss-of-function of Serta or Sertb were assessed at the gene expression level, focusing on the serotonergic signalling pathway, and at the behaviour level, focusing on aggression. Whereas serta mRNA was expressed in all tissues examined, with high expression in the heart, gill and brain, only the brain displayed substantial sertb mRNA expression. In both serta-/- and sertb-/- fish, changes in transcript abundances of multiple components of the serotonin signalling pathway were detected, including proteins involved in serotonin synthesis (tph1a, tph1b, tph2, ddc), packaging (vmat2) and degradation (mao), and serotonin receptors (htr1aa, htr1ab). Using a mirror aggression test, serta-/- male but not female fish exhibited greater aggression than wildtype fish. However, both male and female sertb-/- fish displayed less aggression than their wildtype counterparts. These differences in behaviour between serta-/- and sertb-/- individuals hold promise for increasing our understanding of the neurophysiological basis of aggression in zebrafish.

Tyrosine kinase SRC-induced YAP1-KLF5 module regulates cancer stemness and metastasis in triple-negative breast cancer.

SRC is the first identified oncogene, and its aberrant activation has been implicated as a driving event in tumor initiation and progression. However, its role in cancer stemness regulation and the underlying regulatory mechanism are still elusive. Here, we identified a YAP1 tyrosine phosphorylation-dependent YAP1-KLF5 oncogenic module, as the key downstream mediator of SRC kinase regulating cancer stemness and metastasis in triple-negative breast cancer (TNBC). SRC was overexpressed in TNBC patient tissues and its expression level was highly correlated with the tumor malignancy. SRC activation induced, while inhibition of SRC kinase reduced the cancer stemness, tumor cell growth and metastasis in vitro and in vivo. Transcriptomic and proteomic analysis revealed that SRC-mediated YAP1 tyrosine phosphorylation induced its interaction with Kruppel-like factor 5 (KLF5) to form a YAP1/TEAD-KLF5 complex in TNBC cells. YAP1-KLF5 association further promoted TEAD-mediated transcriptional program independently of canonical Hippo kinases, which eventually gave rise to the enhanced cancer stemness and metastasis. Disruption of YAP1-KLF5 module in TNBC cells dramatically attenuated the SRC-induced cancer stemness and metastasis in vitro and in vivo. Accordingly, co-upregulations of SRC and YAP1-KLF5 module in TNBC tissues were significantly positively correlated with the tumor malignance. Altogether, our work presents a novel tyrosine phosphorylation-dependent YAP1-KLF5 oncogenic module governing SRC-induced cancer stemness and metastasis in TNBC. Therefore, targeting YAP1/KLF5-mediated transcription may provide a promising strategy for TNBC treatment with SRC aberrantly activation.

scEnhancer: a single-cell enhancer resource with annotation across hundreds of tissue/cell types in three species.

Previous studies on enhancers and their target genes were largely based on bulk samples that represent 'average' regulatory activities from a large population of millions of cells, masking the heterogeneity and important effects from the sub-populations. In recent years, single-cell sequencing technology has enabled the profiling of open chromatin accessibility at the single-cell level (scATAC-seq), which can be used to annotate the enhancers and promoters in specific cell types. A comprehensive resource is highly desirable for exploring how the enhancers regulate the target genes at the single-cell level. Hence, we designed a single-cell database scEnhancer (http://enhanceratlas.net/scenhancer/), covering 14 527 776 enhancers and 63 658 600 enhancer-gene interactions from 1 196 906 single cells across 775 tissue/cell types in three species. An unsupervised learning method was employed to sort and combine tens or hundreds of single cells in each tissue/cell type to obtain the consensus enhancers. In addition, we utilized a cis-regulatory network algorithm to identify the enhancer-gene connections. Finally, we provided a user-friendly platform with seven useful modules to search, visualize, and browse the enhancers/genes. This database will facilitate the research community towards a functional analysis of enhancers at the single-cell level.

Inhibition of phosphoglycerate dehydrogenase induces ferroptosis and overcomes enzalutamide resistance in castration-resistant prostate cancer cells.

Phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme in the first step of the serine synthesis pathway (SSP), is overexpressed in multiple types of cancers. The androgen receptor inhibitor enzalutamide (Enza) is the primary therapeutic drug for patients with castration-resistant prostate cancer (CRPC). However, most patients eventually develop resistance to Enza. The association of SSP with Enza resistance remains unclear. In this study, we found that high expression of PHGDH was associated with Enza resistance in CRPC cells. Moreover, increased expression of PHGDH led to ferroptosis resistance by maintaining redox homeostasis in Enza-resistant CRPC cells. Knockdown of PHGDH caused significant GSH reduction, induced lipid peroxides (LipROS) increase and significant cell death, resulting in inhibiting growth of Enza-resistant CRPC cells and sensitizing Enza-resistant CRPC cells to enzalutamide treatment both in vitro and in vivo. We also found that overexpression of PHGDH promoted cell growth and Enza resistance in CRPC cells. Furthermore, pharmacological inhibition of PHGDH by NCT-503 effectively inhibited cell growth, induced ferroptosis, and overcame enzalutamide resistance in Enza-resistant CRPC cells both in vitro and in vivo. Mechanically, NCT-503 triggered ferroptosis by decreasing GSH/GSSG levels and increasing LipROS production as well as suppressing SLC7A11 expression through activation of the p53 signaling pathway. Moreover, stimulating ferroptosis by ferroptosis inducers (FINs) or NCT-503 synergistically sensitized Enza-resistant CRPC cells to enzalutamide. The synergistic effects of NCT-503 and enzalutamide were verified in a xenograft nude mouse model. NCT-503 in combination with enzalutamide effectively restricted the growth of Enza-resistant CRPC xenografts in vivo. Overall, our study highlights the essential roles of increased PHGDH in mediating enzalutamide resistance in CRPC. Therefore, the combination of ferroptosis inducer and targeted inhibition of PHGDH could be a potential therapeutic strategy for overcoming enzalutamide resistance in CRPC.

Confounded association between proton pump inhibitor use and risk of biliary tract cancer: Result from three cohorts.

Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.

The oncogenic roles and clinical implications of YAP/TAZ in breast cancer.

Breast cancer (BC) is the most commonly diagnosed form of cancer and a leading cause of cancer-related deaths among women worldwide. Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are homologous transcriptional coactivators and downstream effectors of Hippo signalling. YAP/TAZ activation has been revealed to play essential roles in multiple events of BC development, including tumour initiation, progression, metastasis, drug resistance and stemness regulations. In this review, we will first give an overview of YAP/TAZ-mediated oncogenesis in BC, and then systematically summarise the oncogenic roles of YAP/TAZ in various BC subtypes, BC stem cells (BCSCs) and tumour microenvironments (TMEs). Based on these findings, we will further discuss the clinical implications of YAP/TAZ-based targeted therapies in BC and the potential future direction.

Genetic factors, adherence to healthy lifestyle behaviors, and risk of bladder cancer.

BACKGROUND: Genetic and lifestyle factors both contribute to the pathogenesis of bladder cancer, but the extent to which the increased genetic risk can be mitigated by adhering to a healthy lifestyle remains unclear. We aimed to investigate the association of combined lifestyle factors with bladder cancer risk within genetic risk groups. METHODS: We conducted a prospective study of 375 998 unrelated participants of European ancestry with genotype and lifestyle data and free of cancer from the UK biobank. We generated a polygenic risk score (PRS) using 16 single nucleotide polymorphisms and a healthy lifestyle score based on body weight, smoking status, physical activity, and diet. Cox models were fitted to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of genetic and lifestyle factors on bladder cancer. RESULTS: During a median follow-up of 11.8 years, 880 participants developed bladder cancer. Compared with those with low PRS, participants with intermediate and high PRS had a higher risk of bladder cancer (HR 1.29, 95% CI 1.07-1.56; HR 1.63, 95% CI 1.32-2.02, respectively). An optimal lifestyle was associated with an approximately 50% lower risk of bladder cancer than a poor lifestyle across all genetic strata. Participants with a high genetic risk and a poor lifestyle had 3.6-fold elevated risk of bladder cancer compared with those with a low genetic risk and an optimal lifestyle (HR 3.63, 95% CI 2.23 -5.91). CONCLUSIONS: Adhering to a healthy lifestyle could substantially reduce the bladder cancer risk across all genetic strata, even for high-genetic risk individuals. For all populations, adopting an intermediate lifestyle is more beneficial than a poor one, and adhering to an optimal lifestyle is the ideal effective strategy for bladder cancer prevention.

A pan-cancer analysis revealing the role of LFNG, MFNG and RFNG in tumor prognosis and microenvironment.

BACKGROUND: Fringe is a glycosyltransferase involved in tumor occurrence and metastasis. However, a comprehensive analysis of the Fringe family members lunatic fringe (LFNG), manic fringe (MFNG), radical fringe (RFNG) in human cancers is lacking. METHODS: In this study, we performed a pan-cancer analysis of Fringe family members in 33 cancer types with transcriptomic, genomic, methylation data from The Cancer Genome Atlas (TCGA) project. The correlation between Fringe family member expression and patient overall survival, copy number variation, methylation, Gene Ontology enrichment, and tumor-infiltrating lymphocytes (TILs) was investigated by using multiple databases, such as cBioPortal, Human Protein Atlas, GeneCards, STRING, MSigDB, TISIDB, and TIMER2. In vitro experiments and immunohistochemical assays were performed to validate our findings. RESULTS: High expression levels of LFNG, MFNG, RFNG were closely associated with poor overall survival in multiple cancers, particularly in pancreatic adenocarcinoma (PAAD), uveal melanoma (UVM), and brain lower-grade glioma (LGG). Copy number variation analysis revealed that diploid and gain mutations of LFNG was significantly increased in PAAD and stomach adenocarcinoma (STAD), and significantly associated with the methylation levels in promoter regions. Significant differential genes between high and low expression groups of these Fringe family members were found to be consistently enriched in immune response and T cell activation pathway, extracellular matrix adhesion pathway, RNA splicing and ion transport pathways. Correlation between the abundance of tumor-infiltrating lymphocytes (TILs) and LFNG, MFNG, and RFNG expression showed that high LFNG expression was associated with lower TIL levels, particularly in PAAD. In vitro experiment by using pancreatic cancer PANC1 cells showed that LFNG overexpression promoted cell proliferation and invasion. Immunohistochemical assay in 90 PAAD patients verified the expression level of LFNG and its relationship with the prognosis. CONCLUSIONS: Our study provides a relatively comprehensive understanding of the expression, mutation, copy number, promoter methylation level changes along with prognosis values of LFNG, MFNG, and RFNG in different tumors. High LFNG expression may serve as a poor prognosis molecular marker for PAAD.

The control of breathing in fishes - historical perspectives and the path ahead.

The study of breathing in fishes has featured prominently in Journal of Experimental Biology (JEB), particularly during the latter half of the past century. Indeed, many of the seminal discoveries in this important sub-field of comparative respiratory physiology were reported first in JEB. The period spanning 1960-1990 (the 'golden age of comparative respiratory physiology') witnessed intense innovation in the development of methods to study the control of breathing. Many of the guiding principles of piscine ventilatory control originated during this period, including our understanding of the dominance of O2 as the driver of ventilation in fish. However, a critical issue - the identity of the peripheral O2 chemoreceptors - remained unanswered until methods for cell isolation, culture and patch-clamp recording established that gill neuroepithelial cells (NECs) respond to hypoxia in vitro. Yet, the role of the NECs and other putative peripheral or central chemoreceptors in the control of ventilation in vivo remains poorly understood. Further progress will be driven by the implementation of genetic tools, most of which can be used in zebrafish (Danio rerio). These tools include CRISPR/Cas9 for selective gene knockout, and Tol2 systems for transgenesis, the latter of which enables optogenetic stimulation of cellular pathways, cellular ablation and in vivo cell-specific biosensing. Using these methods, the next period of discovery will see the identification of the peripheral sensory pathways that initiate ventilatory responses, and will elucidate the nature of their integration within the central nervous system and their link to the efferent motor neurons that control breathing.

Catecholamines modulate the hypoxic ventilatory response of larval zebrafish (Danio rerio).

The hypoxic ventilatory response (HVR) in fish is an important reflex that aids O2 uptake when low environmental O2 levels constrain diffusion. In developing zebrafish (Danio rerio), the acute HVR is multiphasic, consisting of a rapid increase in ventilation frequency (fV) during hypoxia onset, followed by a decline to a stable plateau phase above fV under normoxic conditions. In this study, we examined the potential role of catecholamines in contributing to each of these phases of the dynamic HVR in zebrafish larvae. We showed that adrenaline elicits a dose-dependent ß-adrenoreceptor (AR)-mediated increase in fV that does not require expression of ß1-ARs, as the hyperventilatory response to ß-AR stimulation was unaltered in adrb1-/- mutants, generated by CRISPR/Cas9 knockout. In response to hypoxia and propranolol co-treatment, the magnitude of the rapidly occurring peak increase in fV during hypoxia onset was attenuated (112±14 breaths min-1 without propranolol to 68±17 breaths min-1 with propranolol), whereas the increased fV during the stable phase of the HVR was prevented in both wild type and adrb1-/- mutants. Thus, ß1-AR is not required for the HVR and other ß-ARs, although not required for initiation of the HVR, are involved in setting the maximal increase in fV and in maintaining hyperventilation during continued hypoxia. This adrenergic modulation of the HVR may arise from centrally released catecholamines because adrenaline exposure failed to activate (based on intracellular Ca2+ levels) cranial nerves IX and X, which transmit O2 signals from the pharyngeal arch to the central nervous system.

SRC kinase-mediated signaling pathways and targeted therapies in breast cancer.

Breast cancer (BC) has been ranked the most common malignant tumor throughout the world and is also a leading cause of cancer-related deaths among women. SRC family kinases (SFKs) belong to the non-receptor tyrosine kinase (nRTK) family, which has eleven members sharing similar structure and function. Among them, SRC is the first identified proto-oncogene in mammalian cells. Oncogenic overexpression or activation of SRC has been revealed to play essential roles in multiple events of BC progression, including tumor initiation, growth, metastasis, drug resistance and stemness regulations. In this review, we will first give an overview of SRC kinase and SRC-relevant functions in various subtypes of BC and then systematically summarize SRC-mediated signaling transductions, with particular emphasis on SRC-mediated substrate phosphorylation in BC. Furthermore, we will discuss the progress of SRC-based targeted therapies in BC and the potential future direction.

Efficacy of SCF drug conjugate targeting c-KIT in gastrointestinal stromal tumor.

BACKGROUND: Gastrointestinal stromal tumor (GIST) is a rare type of cancer that occurs in the gastrointestinal tract. The majority of GIST cases carry oncogenic forms of KIT, the receptor for stem cell factor (SCF). Small molecule kinase inhibitor imatinib is effective in prolonging the survival of GIST patients by targeting KIT. However, drug resistance often develops during the therapeutic treatment. Here, we produced a SCF-emtansine drug conjugate (SCF-DM1) with favorable drug efficacy towards GIST cells. METHODS: Recombinant human SCF (rhSCF) was expressed in E. coli cells and further purified with Ni-NTA Sepharose and Phenyl Sepharose. It was then conjugated with DM1, and the conjugated product SCF-DM1 was evaluated using in vitro cell-based assays and in vivo xenograft mouse model. RESULTS: SCF-DM1 was effective in inhibiting imatinib-sensitive and -resistant GIST cell lines and primary tumor cells, with IC50 values of < 30 nM. It induced apoptosis and cell cycle arrest in GIST cells. In xenograft mouse model, SCF-DM1 showed favorable efficacy and safety profiles. CONCLUSIONS: rhSCF is a convenient and effective vector for drug delivery to KIT positive GIST cells. SCF-DM1 is an effective drug candidate to treat imatinib-sensitive and -resistant GIST.

Aquatic surface respiration improves survival during hypoxia in zebrafish (Danio rerio) lacking hypoxia-inducible factor 1-α.

Hypoxia-inducible factor 1-α (Hif-1α), an important transcription factor regulating cellular responses to reductions in O2, previously was shown to improve hypoxia tolerance in zebrafish (Danio rerio). Here, we examined the contribution of Hif-1α to hypoxic survival, focusing on the benefit of aquatic surface respiration (ASR). Wild-type and Hif-1α knockout lines of adult zebrafish were exposed to two levels (moderate or severe) of intermittent hypoxia. Survival was significantly compromised in Hif-1α knockout zebrafish prevented from accessing the surface during severe (16 mmHg) but not moderate (23 mmHg) hypoxia. When allowed access to the surface in severe hypoxia, survival times did not differ between wild-type and Hif-1α knockouts. Performing ASR mitigated the negative effects of the loss of Hif-1α with the knockouts initiating ASR at a higher PO2 threshold and performing ASR for longer than wild-types. The loss of Hif-1α had little impact on survival in fish between 1 and 5 days post-fertilization, but as the larvae aged, their reliance on Hif-1α increased. Similar to adult fish, ASR compensated for the loss of Hif-1α on survival. Together, these results demonstrate that age, hypoxia severity and, in particular, the ability to perform ASR significantly modulate the impact of Hif-1α on survival in hypoxic zebrafish.

Full-length MAVS, a mitochondrial antiviral-signaling protein, inhibits hepatitis E virus replication, requiring JAK-STAT signaling.

Hepatitis E virus (HEV) infection is the leading cause of acute hepatitis worldwide. The mitochondrial antiviral signaling protein (MAVS)-mediated interferon (IFN) response plays a pivotal role in hepatic antiviral immunity. However, little is known about the effect of overexpression of MAVS on HEV infection. Full-length MAVS (FL-MAVS) is the main form of MAVS that increases the production of IFNs. Here, we studied the effect of FL-MAVS on HEV infection. We found that overexpression of FL-MAVS profoundly inhibited HEV replication. Furthermore, we showed that the anti-HEV effect of FL-MAVS is largely dependent on JAK-STAT signaling activation.

Stepwise crosstalk between aberrant Nf1, Tp53 and Rb signalling pathways induces gliomagenesis in zebrafish.

The molecular pathogenesis of glioblastoma indicates that RTK/Ras/PI3K, RB and TP53 pathways are critical for human gliomagenesis. Here, several transgenic zebrafish lines with single or multiple deletions of nf1, tp53 and rb1 in astrocytes, were established to genetically induce gliomagenesis in zebrafish. In the mutant with a single deletion, we found only the nf1 mutation low-efficiently induced tumour incidence, suggesting that the Nf1 pathway is critical for the initiation of gliomagenesis in zebrafish. Combination of mutations, nf1;tp53 and rb1;tp53 combined knockout fish, showed much higher tumour incidences, high-grade histology, increased invasiveness, and shortened survival time. Further bioinformatics analyses demonstrated the alterations in RTK/Ras/PI3K, cell cycle, and focal adhesion pathways, induced by abrogated nf1, tp53, or rb1, were probably the critical stepwise biological events for the initiation and development of gliomagenesis in zebrafish. Gene expression profiling and histological analyses showed the tumours derived from zebrafish have significant similarities to the subgroups of human gliomas. Furthermore, temozolomide treatment effectively suppressed gliomagenesis in these glioma zebrafish models, and the histological responses in temozolomide-treated zebrafish were similar to those observed in clinically treated glioma patients. Thus, our findings will offer a potential tool for genetically investigating gliomagenesis and screening potential targeted anti-tumour compounds for glioma treatment.