CXCR7 Agonist TC14012 Improves Angiogenic Function of Endothelial Progenitor Cells via Activating Akt/eNOS Pathway and Promotes Ischemic Angiogenesis in Diabetic Limb Ischemia.

PURPOSE: Endothelial progenitor cells (EPCs) play a critical role in repairing damaged vessels and triggering ischemic angiogenesis, but their number is reduced and function is impaired under diabetic conditions. Improving EPC function has been considered a promising strategy to ameliorate diabetic vascular complications. In the present study, we aim to investigate whether and how CXCR7 agonist TC14012 promotes the angiogenic function of diabetic EPCs. METHODS: High glucose (HG) treatment was used to mimic the hyperglycemia in diabetes. Tube formation, cell scratch recovery and transwell assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and cleaved-caspase3 expression were used to evaluate the angiogenic capability, cell migration, and apoptosis of EPCs, respectively. Hind limb ischemia (HLI) model was used to appraise the ability of TC14012 in promoting diabetic ischemic angiogenesis in vivo. RESULTS: HG treatment impaired EPC tube formation and migration, and induced EPC apoptosis and oxidative damage, while TC14012 rescued tube formation and migration, and prevented HG-induced apoptosis and oxidative damage of EPCs. Furthermore, these beneficial effects of TC14012 on EPCs were attenuated by specific siRNAs against CXCR7, validating that CXCR7 is a functional target of TC14012 in EPCs. Mechanistic studies demonstrated that HG treatment reduced CXCR7 expression in EPCs, and impaired Akt and endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production; similarly, these signal impairments in HG-exposed EPCs could be rescued by TC14012. However, the protective effects of TC14012 on tube formation and migration, Akt and eNOS phosphorylation, and NO production in HG-treated EPCs were almost completely abolished by siRNAs against CXCR7 or Akt specific inhibitor wortmannin. More importantly, in vivo study showed that TC14012 administration enhanced blood perfusion recovery and angiogenesis in the ischemic hind limb and increased the EPC number in peripheral circulation of db/db mice, demonstrating the capability of TC14012 in promoting EPC mobilization and ischemia angiogenic function. CONCLUSION: TC14012 can prevent EPCs from HG-induced dysfunction and apoptosis, improve eNOS activity and NO production via CXCR7/Akt signal pathway, and promote EPC mobilization and diabetic ischemia angiogenesis.

FGF21 promotes ischaemic angiogenesis and endothelial progenitor cells function under diabetic conditions in an AMPK/NAD+-dependent manner.

Diabetic vascular complications are closely associated with long-term vascular dysfunction and poor neovascularization. Endothelial progenitor cells (EPCs) play pivotal roles in maintaining vascular homeostasis and triggering angiogenesis, and EPC dysfunction contributes to defective angiogenesis and resultant diabetic vascular complications. Fibroblast growth factor 21 (FGF21) has received substantial attention as a potential therapeutic agent for diabetes via regulating glucose and lipid metabolism. However, the effects of FGF21 on diabetic vascular complications remain unclear. In the present study, the in vivo results showed that FGF21 efficiently improved blood perfusion and ischaemic angiogenesis in both type 1 and type 2 diabetic mice, and these effects were accompanied by enhanced EPC mobilization and infiltration into ischaemic muscle tissues and increases in plasma stromal cell-derived factor-1 concentration. The in vitro results revealed that FGF21 directly prevented EPC damage induced by high glucose, and the mechanistic studies demonstrated that nicotinamide adenine dinucleotide (NAD+ ) was dramatically decreased in EPCs challenged with high glucose, whereas FGF21 treatment significantly increased NAD+ content in an AMPK-dependent manner, resulting in improved angiogenic capability of EPCs. These results indicate that FGF21 promotes ischaemic angiogenesis and the angiogenic ability of EPCs under diabetic conditions by activating the AMPK/NAD+ pathway.

Interleukin-1ß augments the angiogenesis of endothelial progenitor cells in an NF-κB/CXCR7-dependent manner.

Endothelial progenitor cells (EPCs) are able to trigger angiogenesis, and pro-inflammatory cytokines have beneficial effects on angiogenesis under physiological and pathological conditions. C-X-C chemokine receptor type 7 (CXCR-7), receptor for stromal cell-derived factor-1, plays a critical role in enhancing EPC angiogenic function. Here, we examined whether CXCR7 mediates the pro-angiogenic effects of the inflammatory cytokine interleukin-1ß (IL-1ß) in EPCs. EPCs were isolated by density gradient centrifugation and angiogenic capability was evaluated in vitro by Matrigel capillary formation assay and fibrin gel bead assay. IL-1ß elevated CXCR7 expression at both the transcriptional and translational levels in a dose- and time-dependent manner, and blockade of the nuclear translocation of NF-κB dramatically attenuated the IL-1ß-mediated up-regulation of CXCR7 expression. IL-1ß stimulation significantly promoted EPCs tube formation and this effect was largely impaired by CXCR7-siRNA transfection. IL-1ß treatment stimulated extracellular signal-regulated kinase 1/2 (Erk1/2) phosphorylation, and inhibition of Erk1/2 phosphorylation partially impaired IL-1ß-induced tube formation of EPCs but without significant effects on CXCR7 expression. Moreover, blocking NF-κB had no significant effects on IL-1ß-stimulated Erk1/2 phosphorylation. These findings indicate that CXCR7 plays an important role in the IL-1ß-enhanced angiogenic capability of EPCs and antagonizing CXCR7 is a potential strategy for inhibiting angiogenesis under inflammatory conditions.

Electroacupuncture Alleviates Pain Responses and Inflammation in Collagen-Induced Arthritis Rats via Suppressing the TLR2/4-MyD88-NF-κB Signaling Pathway.

Results: EA intervention and OxPAPC injection could relieve mechanical allodynia and thermal hyperalgesia caused by CIA. Paw edema and pathological damage of synovium were significantly ameliorated after EA intervention and OxPAPC injection. Furthermore, EA intervention and OxPAPC injection markedly reduced the contents of serum TNF-α, IL-1ß, and IL-6, as well as the protein expression levels of synovial TLR2, TLR4, MyD88, and NF-κB p-p65. In particular, the expression of TLR2 and TLR4 on synovial fibroblasts and macrophages in synovium was significantly reduced by EA intervention. Conclusions: Repeated EA stimulation at ST36 and SP6 can effectively relieve joint pain and synovial inflammation caused by RA in CIA rats. The analgesic and anti-inflammatory effect of EA may be closely related to the inhibition of innate immune responses driven by the TLR2/4-MyD88-NF-κB signaling pathway in the synovium.

PbANK facilitates the long-distance movement of the PbWoxT1-PbPTB3 RNP complex by degrading deposited callose.

Grafting horticultural crops can result in phenotypic changes in the grafted materials due to the movement of macromolecular signals, including RNAs and proteins, across the graft union; however, little is known about the composition of trafficking ribonucleoprotein (RNP) complexes or how these macromolecules are transported. Here, we used the core of PbPTB3-PbWoxT1 RNP complex, PbPTB3, as bait to screen Pyrus betulaefolia cDNA library for its interaction partners. We identified an ankyrin protein, PbANK, that interacts with PbPTB3 to facilitate its transport through the phloem alongside PbWoxT1 mRNA. Heterografting experiments showed that silencing PbANK in rootstock prevented the transport of PbPTB3 and PbWoxT1 mRNA from the rootstock to the scion. Similarly, heterologous grafting experiments demonstrated that PbANK itself cannot be transported over long distances through a graft union. Fluorescence microscopy showed that silencing ANK affected the intercellular diffusion of PbPTB3 and increased callose deposition at plasmodesmata. Collectively, these findings demonstrate that PbANK mediates the long-distance movement of PbPTB3 and PbWoxT1 by degrading callose to increase the efficiency of cell-to-cell movement.

[Effects of transcutaneous auricular vagus nerve stimulation on bone and cartilage destruction in rats with rheumatoid arthritis].

OBJECTIVE: To observe the alleviating effect of transcutaneous auricular vagus nerve stimulation (taVNS) on articular cartilage and bone destruction in rats with collagen-induced arthritis (CIA), and explore the cellular and molecular mechanisms of taVNS against rheumatoid arthritis (RA). METHODS: The male SD rats were randomly divided into normal control group (n=12), model group (n=12), and taVNS group (n=12). The CIA rat model was established by multi-point injection of emulsion prepared from type Ⅱ bovine collagen and Freund's incomplete adjuvant into the root of rat tail. The rats in the taVNS group were treated with taVNS at bilateral auricular conchae, 30 min per time, once a day, for consecutive 28 d. The cartilage destruction of the ankle joint was observed by safranin O-fast green staining, the production of osteoclasts in the joint tissue by tartrate-resistant acid phosphatase (TRAP) staining, and the bone erosion by X-ray and Micro-CT imaging. The protein expression levels of matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, receptor activator of nuclear factor-κB ligand (RANKL), and osteoprotegerin (OPG) in the synovial tissues were detected by Western blot. RESULTS: Compared with the normal control group, the CIA rats presented with typical RA symptoms and elevated arthritis index (AI,P<0.05). After intervention with taVNS, the AI remarkably declined in comparison with that in the model group (P<0.05). Compared with the control group, the model group displayed loss of cartilage matrix in the ankle joint, thinned cartilage layer, obvious cartilage damage, and increased number of osteo-clasts in the joint (P<0.01); the imaging results showed bone loss and three-dimensional structural destruction of ankle joint and aggravated bone erosion (P<0.01); the expression levels of MMP-1, MMP-3 and MMP-13, and RANKL/OPG ratio were significantly elevated in the synovial tissue of ankle joint (P<0.01, P<0.05), while the expression level of OPG was decreased (P<0.05). Compared with the model group, taVNS resulted in relatively intact cartilage layer of ankle joint, alleviated cartilage destruction, decreased number of osteoclasts (P<0.01), improved bone erosion, loss, and three-dimensional structural destruction (P<0.01), and diminished MMP-1, MMP-3, and MMP-13 expression and RANKL/OPG ratio in the synovial tissue of ankle joint (P<0.05, P<0.01), while the expression level of OPG was increased (P<0.05). CONCLUSION: taVNS effectively relieves bone and cartilage destruction in CIA rats, which might be related to its efficacy in reducing the production of osteoclasts in joint tissues and down-regulating the expression levels of MMP-1, MMP-3 and MMP-13, and RANKL/OPG ratio.

[Effect of electroacupuncture on articular morphological changes and serum inflammatory factors and synovial MMPs in collagen-induced arthritis rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of "Zusanli"(ST36) and "Sanyinjiao"(SP6) on serum TNF-α, IL-1ß, and IL-6 and expression of synovial matrimetalloproteinases (MMPs) and articular morphology in collagen-induced arthritis (CIA) rats, so as to explore its mechanisms underlying relief of arthritis. METHODS: Thirty male SD rats were randomly divided into normal control, CIA model and EA groups (n=10 rats per group). The arthritis model was induced by multi-point intradermal injection of bovine type Ⅱ collagen emulsion. EA (2 Hz/100 Hz, 1 mA) was applied to bilateral ST36 and SP6 for 30 min, once a day for 28 days. The hind-limb paw volume was measured and the arthritis index (AI) score given according to the swelling degree, rigidity and deformity of the ankle joint (0-4 points). After EA intervention, the morphological damage of the affected ankle joints was revealed by H.E. staining, safranin O-fast green staining, and tartrate-resistant acid phosphatase (TRAP) staining, separately. The levels of serum TNF-α, IL-1ß, and IL-6 were measured by ELISA, and the expression levels of MMP-1, MMP-3, MMP-13, and receptor activator of nuclear factor Kappa B ligand (RANKL) in the synovial tissue were detected by Western blot. RESULTS: Compared with the normal control group, the paw volume, AI score, TRAP-revealed number of osteoclasts, contents of serum TNF-α, IL-1ß and IL-6, and expression levels of MMP-1, MMP-3, MMP-13 and RANKL proteins were significantly increased in the model group (P<0.01, P<0.05). Following the intervention, the paw volume, AI score, number of osteoclasts, contents of serum TNF- α, IL-1ß and IL-6, and expression levels of MMP-1, MMP-3, MMP-13 and RANKL proteins were significantly decreased in the EA group (P<0.05, P<0.01) in contrast to the model group. H.E. and safranin O-fast green staining showed rough articular cartilage surface with thinned cartilage layer, obvious hyperplasia of the synovial tissue with many inflammatory cells, and serious damage and degradation of the cartilage matrix in the model group, these situations were relatively milder in the EA group. CONCLUSION: EA of ST36 and SP6 can reduce the articular damage in collagen-induced arthritis rats, which is associated with its function in reducing inflammatory response and down-regulating the expression of synovial MMP-1, MMP-3, MMP-13 and RANKL proteins.

Nuclear translocation of ATG5 induces DNA mismatch repair deficiency (MMR-D)/microsatellite instability (MSI) via interacting with Mis18α in colorectal cancer.

BACKGROUND AND PURPOSE: It is well known that microsatellite instability-high (MSI-H) is associated with 5-fluorouracil (5-FU) resistance in colorectal cancer. MSI-H is the phenotype of DNA mismatch repair deficiency (MMR-D), mainly occurring due to hypermethylation of MLH1 promoter CpG island. However, the mechanisms of MMR-D/MSI-H are unclear. We aim to investigate the pathway of MMR-D/MSI-H involved in 5-FU resistance. EXPERIMENTAL APPROACH: Human colorectal cancer specimens were diagnosed for MSI-H by immunohistochemistry and western blotting. Proteome microarray interactome assay was performed to screen nuclear proteins interacting with ATG5. Nuclear ATG5 and ATG5-Mis18α overexpression were analysed in ATG5high colorectal cancer bearing mice. The methylation assay determined the hypermethylation of hMLH1 promoter CpG island in freshly isolated human colorectal cancer tissue samples and HT29atg5 and SW480atg5 cancer cells. KEY RESULTS: In ATG5high colorectal cancer patients, 5-FU-based therapy resulted in nuclear translocation of ATG5, leading to MSI-H. Colorectal cancer in Atg5 Tg mice demonstrated 5-FU resistance, compared to Atg5+/- and WT mice. Proteome microarray assay identified Mis18α, a protein localized on the centromere and a source for methylation of the underlying chromatin, which responded to the translocated nuclear ATG5 leading to ATG5-Mis18α conjugate overexpression. This resulted in MLH1 deficiency due to hypermethylation of hMLH1 promoter CpG island, while the deletion of nuclear Mis18α failed to induce ATG5-Mis18α complex and MMR-D/MSI-H. CONCLUSIONS AND IMPLICATIONS: Nuclear ATG5 resulted in MMR-D/MSI-H through its interaction with Mis18α in ATG5high colorectal cancer cells. We suggest that ATG5-Mis18α or Mis18α may be a therapeutic target for treating colorectal cancer.

Exosome-encapsulated miRNAs contribute to CXCL12/CXCR4-induced liver metastasis of colorectal cancer by enhancing M2 polarization of macrophages.

Tumor-associated macrophages (TAMs) are important immunocytes associated with cancer metastasis. However, whether TAMs play a dominant role in mediating CXCL12/CXCR4-induced liver metastasis of colorectal cancer (CRC) remains unexplored. Herein, we found that CD206+ TAMs, which infiltrated at the invasive front, were correlated with CXCR4 expression and liver metastasis of CRC in clinical specimens. Several miRNAs (miR-25-3p, miR-130b-3p, miR-425-5p), upregulated in CRC cells by activation of the CXCL12/CXCR4 axis, could be transferred to macrophages via exosomes. These exosomal miRNAs induced M2 polarization of macrophages by regulating PTEN through activation of PI3K/Akt signaling pathway. In turn, M2 polarized macrophages promoted cancer metastasis by enhancing epithelial-mesenchymal transition (EMT) and secreting vascular endothelial growth factor (VEGF). Co-culture of CRC cells with macrophages transfected with these miRNAs or treated with exosomes enhanced their metastatic capacity both in vitro and in vivo. Clinically, the serum levels of exosomal miR-25-3p, miR-130b-3p and miR-425-5p were correlated with progression and metastasis of CRC. In conclusion, these results reveal a crucial role of exosomal miRNAs in mediating the crosstalk between CXCR4 overexpressing cancer cells and TAMs, providing potential therapeutic targets for circumventing liver metastasis of CRC.

SphK2 confers 5-fluorouracil resistance to colorectal cancer via upregulating H3K56ac-mediated DPD expression.

Aberrant sphingolipid metabolism has been implicated in chemoresistance, but the underlying mechanisms are still poorly understood. Herein we revealed a previously unrecognized mechanism of 5-fluorouracil (5-FU) resistance contributed by high SphK2-upregulated dihydropyrimidine dehydrogenase (DPD) in colorectal cancer (CRC), which is evidenced from human CRC specimens, animal models, and cancer cell lines. TMA samples from randomly selected 60 CRC specimens firstly identified the clinical correlation between high SphK2 and increased DPD (p < 0.001). Then the regulatory mechanism was explored in CRC models of villin-SphK2 Tg mice, SphK2-/-mice, and human CRC cells xenografted nude mice. Assays of ChIP-Seq and luciferase reporter gene demonstrated that high SphK2 upregulated DPD through promoting the HDAC1-mediated H3K56ac, leading to the degradation of intracellular 5-FU into inactive α-fluoro-ß-alanine (FBAL). Lastly, inhibition of SphK2 by SLR080811 exhibited excellent inhibition on DPD expression and potently reversed 5-FU resistance in colorectal tumors of villin-SphK2 Tg mice. Overall, this study manifests that SphK2high conferred 5-FU resistance through upregulating tumoral DPD, which highlights the strategies of blocking SphK2 to overcome 5-FU resistance in CRC.

Endothelial Overexpression of Metallothionein Prevents Diabetes-Induced Impairment in Ischemia Angiogenesis Through Preservation of HIF-1α/SDF-1/VEGF Signaling in Endothelial Progenitor Cells.

Diabetes-induced oxidative stress is one of the major contributors to dysfunction of endothelial progenitor cells (EPCs) and impaired endothelial regeneration. Thus, we tested whether increasing antioxidant protein metallothionein (MT) in EPCs promotes angiogenesis in a hind limb ischemia (HLI) model in endothelial MT transgenic (JTMT) mice with high-fat diet- and streptozocin-induced diabetes. Compared with littermate wild-type (WT) diabetic mice, JTMT diabetic mice had improved blood flow recovery and angiogenesis after HLI. Similarly, transplantation of JTMT bone marrow-derived mononuclear cells (BM-MNCs) stimulated greater blood flow recovery in db/db mice with HLI than did WT BM-MNCs. The improved recovery was associated with augmented EPC mobilization and angiogenic function. Further, cultured EPCs from patients with diabetes exhibited decreased MT expression, increased cell apoptosis, and impaired tube formation, while cultured JTMT EPCs had enhanced cell survival, migration, and tube formation in hypoxic/hyperglycemic conditions compared with WT EPCs. Mechanistically, MT overexpression enhanced hypoxia-inducible factor 1α (HIF-1α), stromal cell-derived factor (SDF-1), and vascular endothelial growth factor (VEGF) expression and reduced oxidative stress in ischemic tissues. MT's pro-EPC effects were abrogated by siRNA knockdown of HIF-1α without affecting its antioxidant action. These results indicate that endothelial MT overexpression is sufficient to protect against diabetes-induced impairment of angiogenesis by promoting EPC function, most likely through upregulation of HIF-1α/SDF-1/VEGF signaling and reducing oxidative stress.

CXCL12/CXCR4 promotes inflammation-driven colorectal cancer progression through activation of RhoA signaling by sponging miR-133a-3p.

BACKGROUND: Activation of CXCL12/CXCR4 axis has been found to be associated with invasion and metastasis in many cancers. However, the underlying mechanism remains elusive. Increasing data highlight that non-coding RNAs are linked to CRC progression. METHODS: The effects of CXCR4 were investigated using villin-CXCR4 transgenic mice model by flow cytometry assay, immunohistochemistry, and Western blot. The mechanism was explored through bioinformatics, luciferase reporter assay and RNA immunoprecipitation assay. RESULTS: We found that high CXCR4 expression exacerbated colitis-associated cancer in villin-CXCR4 transgenic mice. CXCR4+/-Apcmin/+ compound mutant mice demonstrated higher colorectal tumorigenesis than Apcmin/+ mice. Furthermore, overexpression of CXCR4 was found to promote the epithelial-mesenchymal transition (EMT) and infiltration of myeloid-derived suppressor cells (MDSCs) and macrophages in colonic tissue, accelerating colitis-associated and Apc mutation-driven colorectal tumorigenesis and progression. Notably, miR-133a-3p was found to be significantly decreased in HCT116 cells overexpressing CXCR4 by miRNA sequencing. miR-133a-3p was proved to target RhoA, which is involved in cytoskeletal reorganization that drive cell motility. Importantly, CXCL12/CXCR4-induced upregulation of lncRNA XIST functioned as a ceRNA to sponge miR-133a-3p, thereby liberating the repression of RhoA by miR-133a-3p. The negative correlation of miR-133a-3p with RhoA was also confirmed in human CRC tissues and CXCR4+/- mice. CONCLUSIONS: Our findings revealed the critical role of CXCR4 in promoting progression of inflammatory colorectal cancer through recruiting immunocytes and enhancing cytoskeletal remodeling by lncRNA XIST/ miR-133a-3p/ RhoA signaling. These results provide novel potential therapeutic targets for hindering CXCL12/CXCR4-induced CRC progression.

Different effects of propofol and dexmedetomidine sedation on electroencephalogram patterns: Wakefulness, moderate sedation, deep sedation and recovery.

Sedation induces changes in electroencephalography (EEG) dynamics. However, the distinct EEG dynamic characteristics at comparable sedation levels have not been well studied, resulting in potential interpretation errors in EEG monitoring during sedation. We aimed to analyze the EEG dynamics of dexmedetomidine and propofol at comparable sedation levels and to explore EEG changes with increased sedation levels for each agent. We measured the Bispectral Index (BIS) and 20-channel EEG under dexmedetomidine and propofol sedation from wakefulness, moderate sedation, and deep sedation to recovery in healthy volunteers (n = 10) in a randomized, 2-day, crossover study. Observer's Assessment of Alertness and Sedation (OAA/S) score was used to assess sedation levels. Despite similar changes in increased delta oscillations, multiple differences in the EEG spatiotemporal dynamics were observed between these two agents. During moderate sedation, both dexmedetomidine and propofol induced increased spindle power; however, dexmedetomidine decreased the global alpha/beta/gamma power, whereas propofol decreased the alpha power in the occipital area and increased the global spindle/beta/gamma power. During deep sedation, dexmedetomidine was associated with increased fronto-central spindle power and decreased global alpha/beta/gamma power, but propofol was associated with increased theta/alpha/spindle/beta power, which was maximized in the frontal area. The transition of topographic alpha/spindle/beta power distribution from moderate sedation to deep sedation completely differed between these two agents. Our study demonstrated that there was a distinct hierarchy of EEG changes with increased sedation depths by propofol and dexmedetomidine. Differences in EEG dynamics at the same sedation level might account for differences in the BIS value and reflect the different sedation mechanisms. EEG-based clinical sedation monitoring should consider the effect of drug types on EEG dynamics.

CXCL12/CXCR4 axis induced miR-125b promotes invasion and confers 5-fluorouracil resistance through enhancing autophagy in colorectal cancer.

The activation of CXCL12/CXCR4 axis is associated with potential progression of cancer, such as invasion, metastasis and chemoresistance. However, the underlying mechanisms of CXCL12/CXCR4 axis and cancer progression have been poorly explored. We hypothesized that miRNAs might be critical downstream mediators of CXCL12/CXCR4 axis involved in cancer invasion and chemoresistance in CRC. In human CRC cells, we found that the activation of CXCL12/CXCR4 axis promoted epithelial-mesenchymal transition (EMT) and concurrent upregulation of miR-125b. Overexpression of miR-125b robustly triggered EMT and cancer invasion, which in turn enhanced the expression of CXCR4. Importantly, the reciprocal positive feedback loop between CXCR4 and miR-125b further activated the Wnt/ß-catenin signaling by targeting Adenomatous polyposis coli (APC) gene. There was a negative correlation of the expression of miR-125b with APC mRNA in paired human colorectal tissue specimens. Further experiments indicated a role of miR-125b in conferring 5-fluorouracil (5-FU) resistance in CRC probably through increasing autophagy both in vitro and in vivo. MiR-125b functions as an important downstream mediator upon the activation of CXCL12/CXCR4 axis that involved in EMT, invasion and 5-FU resistance of CRC. These findings shed a new insight into the role of miR-125b and provide a potential therapeutic target in CRC.

Overexpression of SphK2 contributes to ATRA resistance in colon cancer through rapid degradation of cytoplasmic RXRα by K48/K63-linked polyubiquitination.

The resistance mechanisms that limit the efficacy of retinoid therapy in cancer are poorly understood. Sphingosine kinase 2 (SphK2) is a highly conserved enzyme that is mainly located in the nucleus and endoplasmic reticulum. Unlike well-studied sphingosine kinase 1 (SphK1) located in the cytosol, little has yet understood the functions of SphK2. Here we show that SphK2 overexpression contributes to the resistance of all-trans retinoic acid (ATRA) therapy in colon cancer through rapid degradation of cytoplasmic retinoid X receptor α (RXRα) by lysine 48 (K48)- and lysine 63 (K63)-based polyubiquitination. Human colonic adenocarcinoma HCT-116 cells transfected with SphK2 (HCT-116Sphk2 cells) demonstrate resistance to ATRA therapy as determined by in vitro and in vivo assays. Sphk2 overexpression increases the ATRA-induced nuclear RXRα export to cytoplasm and then rapidly degrades RXRα through the polyubiquitination pathway. We further show that Sphk2 activates the ubiquitin-proteasome system through the signal mechanisms of (1) K48-linked proteosomal degradation and (2) K63-linked ubiquitin-dependent autophagic degradation. These results provide new insights into the biological functions of Sphk2 and the molecular mechanisms that underlie the Sphk2-mediated resistance to retinoid therapy.

Problematic Internet Users' Discounting Behaviors Reflect an Inability to Delay Gratification, Not Risk Taking.

The relationship between impulse control disorder (ICD) behaviors and problematic Internet use (PIU) has been established in the literature. Our aim was to further investigate whether the ICDs of individuals suffering from PIU primarily involve an inability to delay gratification or a tendency to take risks. Using delay and probability discounting tasks, we compared the subjective value of discounting between PIU individuals and controls in conditions of gaining or losing different monetary amounts. The results of the present study revealed a significant positive relationship between PIU and impulsivity scores. PIU individuals discounted delayed amounts more steeply than controls, regardless of the reward sign and monetary amount. Conversely, there were no significant group differences in the probability discounting task. These findings suggest that PIU individuals may be more impulsive than controls when impulsivity is framed as insensitivity to delayed outcomes rather than as a tendency to take risks, which is inconsistent with the view of impulsivity as a general trait.

Naringin, a natural dietary compound, prevents intestinal tumorigenesis in Apc (Min/+) mouse model.

PURPOSE: Naringin is a natural dietary flavonoid compound. We aimed to evaluate the effects of naringin on intestinal tumorigenesis in the adenomatous polyposis coli multiple intestinal neoplasia (Apc (Min/+)) mouse model. METHODS: Apc (Min/+) mice were given either naringin (150 mg/kg) or vehicle by p.o. gavage daily for 12 consecutive weeks. Mice were killed with ether, and blood samples were collected to assess the concentrations of IL-6 and PGE2. Total intestines were removed, and the number of polyps was examined. Tissue samples of intestinal polyps were subjected to the assays of histopathology, immunohistochemical analysis and Western blotting analysis. RESULTS: Apc (Min/+) mice fed with naringin developed less and smaller polyps in total intestines. Naringin prevented intestinal tumorigenesis without adverse effects. Histopathologic analysis revealed the reduction of dysplastic cells and dysplasia in the adenomatous polyps. The treatments' effects might arise from its anti-proliferation, induction of apoptosis and modulation of GSK-3ß and APC/ß-catenin signaling pathways. Naringin also exerted its effects on tumorigenesis through anti-chronic inflammation. CONCLUSION: Naringin prevented intestinal tumorigenesis likely through a collection of activities including anti-proliferation, induction of apoptosis, modulation of GSK-3ß and APC/ß-catenin pathways and anti-inflammation. Naringin is a potential chemopreventive agent for reducing the risk of colonic cancers.

Chemoprevention of intestinal tumorigenesis by the natural dietary flavonoid myricetin in APCMin/+ mice.

Myricetin is a natural dietary flavonoid compound. We evaluated the efficacy of myricetin against intestinal tumorigenesis in adenomatous polyposis coli multiple intestinal neoplasia (APCMin/+) mice. Myricetin was given orally once a day for 12 consecutive weeks. APCMin/+ mice fed with myricetin developed fewer and smaller polyps without any adverse effects. Histopathological analysis showed a decreased number of dysplastic cells and degree of dysplasia in each polyp. Immunohistochemical and western blot analysis revealed that myricetin selectively inhibits cell proliferation and induces apoptosis in adenomatous polyps. The effects of myricetin were associated with a modulation the GSK-3ß and Wnt/ß-catenin pathways. ELISA analysis showed a reduced concentration of pro-inflammatory cytokines IL-6 and PGE2 in blood, which were elevated in APCMin/+ mice. The effect of myricetin treatment was more prominent in the adenomatous polyps originating in the colon. Further studies showed that myricetin downregulates the phosphorylated p38 MAPK/Akt/mTOR signaling pathways, which may be the mechanisms for the inhibition of adenomatous polyps by myricetin. Taken together, our data show that myricetin inhibits intestinal tumorigenesis through a collection of biological activities. Given these results, we suggest that myricetin could be used preventatively to reduce the risk of developing colon cancers.

Dissociable early attentional control mechanisms underlying cognitive and affective conflicts.

It has been well documented that cognitive conflict is sensitive to the relative proportion of congruent and incongruent trials. However, few studies have examined whether affective conflict processing is modulated as a function of proportion congruency (PC). To address this question we recorded event-related potentials (ERP) while subjects performed both cognitive and affective face-word Stroop tasks. By varying the proportion of congruent and incongruent trials in each block, we examined the extent to which PC impacts both cognitive and affective conflict control at different temporal stages. Results showed that in the cognitive task an anteriorly localized early N2 component occurred predominantly in the low proportion congruency context, whereas in the affective task it was found to occur in the high proportion congruency one. The N2 effects across the two tasks were localized to the dorsolateral prefrontal cortex, where responses were increased in the cognitive task but decreased in the affective one. Furthermore, high proportions of congruent items produced both larger amplitude of a posteriorly localized sustained potential component and a larger behavioral Stroop effect in cognitive and affective tasks. Our findings suggest that cognitive and affective conflicts engage early dissociable attentional control mechanisms and a later common conflict response system.