Increasing Sufu gene dosage reveals its unorthodox role in promoting polydactyly and medulloblastoma tumorigenesis.

Suppressor of fused (SUFU) is widely regarded as a key negative regulator of the sonic hedgehog (SHH) morphogenic pathway and a known tumor suppressor of medulloblastoma (MB). However, we report here that SUFU expression was markedly increased in 75% of specimens compiled in a tissue array comprising 49 unstratified MBs. The SUFU and GLI1 expression levels in this MB array showed strong positive correlation, which was also identified in a large public data set containing 736 MBs. We further report that increasing Sufu gene dosage in mice caused preaxial polydactyly, which was associated with the expansion of the Gli3 domain in the anterior limb bud and heightened Shh signaling responses during embryonic development. Increasing Sufu gene dosage also led to accelerated cerebellar development and, when combined with ablation of the Shh receptor encoded by Patched1 (Ptch1), promoted MB tumorigenesis. These data reveal multifaceted roles of SUFU in promoting MB tumorigenesis by enhancing SHH signaling. This revelation clarifies potentially counterintuitive clinical observation of high SUFU expression in MBs and may pave way for novel strategies to reduce or reverse MB progression.

Solid pseudopapillary neoplasm: Report of a case of primary ovarian origin and review of the literature.

Background: Solid pseudopapillary neoplasms (SPNs) are uncommon tumors of low malignancy with a generally favorable prognosis, mostly originating from the pancreas. To date, 12 cases of SPNs with a primary ovarian origin (SPN-Os) have been reported globally, and their detailed characteristics have not been fully elucidated. Case description: We reported the 13th SPN-O case, which occurred in a 52-year-old woman with an 18.5 cm left ovarian mass. Four imaging methods, including ultrasound, computed tomography, magnetic resonance imaging and positron emission tomography, were utilized before surgery. An elevated level of serum cancer antigen 125 was detected and a total hysterectomy plus bilateral salpingo-oophorectomy was performed. Microscopic examination revealed a typical solid pseudopapillary structure. The tumor cells were stained focally for pan-cytokeratin, synaptophysin, CD99 and CD10, while ß-catenin, vimentin and CD56 were diffusely expressed. The Ki-67 proliferation index was 3%, and immunohistochemical (IHC) staining for chromogranin-A, inhibin-a, and E-cadherin was negative. No evidence of recurrence or metastasis was observed by clinical and imaging data during a 5-month postoperative follow-up. Conclusion: This is a report of an unusual case of a primary ovarian SPN with an up-to-date review of SPN-Os. A minimum combination of imaging methods and IHC stains was proposed for SPN-Os, which may prove beneficial in clinical practice.

Learning to Discover Multi-Class Attentional Regions for Multi-Label Image Recognition.

Multi-label image recognition is a practical and challenging task compared to single-label image classification. However, previous works may be suboptimal because of a great number of object proposals or complex attentional region generation modules. In this paper, we propose a simple but efficient two-stream framework to recognize multi-category objects from global image to local regions, similar to how human beings perceive objects. To bridge the gap between global and local streams, we propose a multi-class attentional region module which aims to make the number of attentional regions as small as possible and keep the diversity of these regions as high as possible. Our method can efficiently and effectively recognize multi-class objects with an affordable computation cost and a parameter-free region localization module. Over three benchmarks on multi-label image classification, our method achieves new state-of-the-art results with a single model only using image semantics without label dependency. In addition, the effectiveness of the proposed method is extensively demonstrated under different factors such as global pooling strategy, input size and network architecture. Code has been made available at https://github.com/gaobb/MCAR.

YTHDF2 is a potential target of AML1/ETO-HIF1α loop-mediated cell proliferation in t(8;21) AML.

The t(8;21) fusion product, AML1/ETO, and hypoxia-inducible factor 1α (HIF1α) form a feed-forward transcription loop that cooperatively transactivates the DNA methyltransferase 3a gene promoter that leads to DNA hypermethylation and drives leukemia cell growth. Suppression of the RNA N6-methyladenosine (m6A)-reader enzyme YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) specifically compromises cancer stem cells in acute myeloid leukemia (AML) but promotes hematopoietic stem cell expansion without derailing normal hematopoiesis. However, the relevance of expression between AML1/ETO-HIF1α loop and YTHDF2, and its functional relationship with t(8;21) AML have not been documented. Here, we show that YTHDF2 is highly expressed in t(8;21) AML patients and associated with a higher risk of relapse and inferior relapse-free survival. Knockdown of YTHDF2 in leukemia cells causes an impaired cell proliferation rate in vitro and in mice. Mechanistically, HIF1α is able to bind to the hypoxia-response elements of the 5'-untranslated region of the YTHDF2 gene and promotes the transactivity of the YTHDF2 promoter. Knockdown and overexpression of either AML1/ETO or HIF1α resulted in decreased and increased YTHDF2 protein and mRNA expression in t(8;21) AML cells. In particular, knockdown of YTHDF2 resulted in increased global mRNA m6A levels in t(8;21) AML cells, accompanied by increased TNF receptor superfamily member 1b (TNFRSF1b) mRNA and protein expression levels. Last, we demonstrated that the m6A methylation and expression levels of the TNFRSF1b gene were both negatively correlated with HIF1α expression levels. In conclusion, YTHDF2 is a downstream target of the AML1/ETO-HIF1α loop and promotes cell proliferation probably by modulating the global m6A methylation in t(8;21) AML.

Preparation of carbon-based AuAg alloy nanoparticles by using the heterometallic [Au4Ag4] cluster for efficient oxidative coupling of anilines.

We herein report the preparation of unique heteroatom-doped and carbon-based AuAg alloy nanoparticles (NPs) via the pyrolysis of a structurally defined octanuclear heterometallic Au(i)-Ag(i) cluster [Au4Ag4(Dppy)4(Tab)4(MeCN)4](PF6)8 (2, Dppy = diphenylphosphine-2-pyridine and Tab = 4-(trimethylammonio)benzenethiolate). This cluster-precursor approach exerts a fine control over the spatial arrangement, size and uniformity of the AuAg alloy NPs as well as the doped heteroatoms (P, N, F and S). The optimized material prepared at 450 °C efficiently catalyzes the oxidative coupling of anilines to yield azobenzenes under mild conditions.

[Cd(H2O)6]@{Cd6Cl4(nico)12[Hg(Tab)2(µ-Cl)]2}: a heterometallic host-guest icosidodecahedron cage via hierarchical assembly.

Complexation of a preformed complex [Hg(Tab)2](PF6)2 (1) with nicotinic acid in the presence of Et3N afforded a mononuclear complex [Hg(Tab)2(nico)]2(PF6)2 (2) (nico = nicotinate, Tab = 4-(trimethylammonio)benzenethiolate) which, upon subsequent treatment with one or three equiv. of CdCl2·2.5H2O, gave rise to an unprecedented heterometallic cage complex [Cd(H2O)6]@{Cd6Cl4(nico)12[Hg(Tab)2(µ-Cl)]2} (3) or a simple salt of [Hg(Tab)2][CdCl4] (4).

Deep Label Distribution Learning With Label Ambiguity.

Convolutional neural networks (ConvNets) have achieved excellent recognition performance in various visual recognition tasks. A large labeled training set is one of the most important factors for its success. However, it is difficult to collect sufficient training images with precise labels in some domains, such as apparent age estimation, head pose estimation, multilabel classification, and semantic segmentation. Fortunately, there is ambiguous information among labels, which makes these tasks different from traditional classification. Based on this observation, we convert the label of each image into a discrete label distribution, and learn the label distribution by minimizing a Kullback-Leibler divergence between the predicted and ground-truth label distributions using deep ConvNets. The proposed deep label distribution learning (DLDL) method effectively utilizes the label ambiguity in both feature learning and classifier learning, which help prevent the network from overfitting even when the training set is small. Experimental results show that the proposed approach produces significantly better results than the state-of-the-art methods for age estimation and head pose estimation. At the same time, it also improves recognition performance for multi-label classification and semantic segmentation tasks.

Palladium(ii) and palladium(ii)-silver(i) complexes with N-heterocyclic carbene and zwitterionic thiolate mixed ligands: synthesis, structural characterization and catalytic properties.

The integration of a geometrically rigid Pd(ii), a coordinatively monotonous N-heterocyclic carbene 1,3-dimethylimidazoline-2-ylidene (IMe), and a flexible zwitterionic thiolate 4-(trimethylammonio)benzenethiolate (Tab) affords a class of Pd-IMe-Tab complexes with various nuclearities, namely, trans-[Pd(IMe)2(Tab)2](OTf)2 (2, mononuclear), cis-[Pd(IMe)2(Tab)2](OTf)(Cl) (3a, mononuclear), cis-[Pd(IMe)2(Tab)2](PF6)2·MeCN (3b·MeCN, mononuclear), [Pd2(IMe)4(Tab)2](PF6)4·2MeCN (4·2MeCN, dinuclear) and [Pd4(IMe)4(Tab)6](OTf)6(Cl)2 (5, tetranuclear). Further presence of Ag(i) in the assembly provides a heterometallic octanuclear cluster of [Pd4Ag4(IMe)8(Tab)10](PF6)12 (6). Compounds 2-6 are formed by the reaction of trans-Pd(IMe)2Cl2 (1) with various additional reagents via different reaction pathways. These compounds are characterized by means of FT-IR, 1H and 13C NMR, ESI-MS, elemental analysis and X-ray crystallography. Notably, the skeleton of compound 5 features a [Pd4S4] parallelogram wherein each of the four Pd(ii) centers bisects the edge defined by the S atoms. The main skeleton of compound 6 is an oval-shaped Pd4Ag4S10 unit, featuring an edge-fused norbornane-like (Pd2Ag4S6) framework appended by two additional PdS2 motifs at the polar positions. Compounds 5 and 6 also feature PdPd (5), PdAg and AgAg (6) interactions. Compound 5 as a representative example is highly effective at catalyzing Suzuki-Miyaura couplings in water, highlighting the potential of applying these types of homo- and heterometallic clusters as catalysts for organic transformations in environmentally benign media.

One Unique 1D Silver(I)-Bromide-Thiol Coordination Polymer Used for Highly Efficient Chemiresistive Sensing of Ammonia and Amines in Water.

Reaction of AgBr with TabHPF6 (TabH = 4-(trimethylammonio)benzenethiol) readily produces a unique one-dimensional coordination polymer [(TabH)(AgBr2)]n (1), consisting of anionic chains [AgBr2]n(n-) with hydrogen bonds to TabH(+) cations. By examining its electrical resistance and stability upon exposure to ammonia and seven common organic amines in water under ambient conditions, compound 1 is found to exhibit good stability and reproducibly high sensitivity toward these analytes at low concentrations. Especially, it can selectively detect NH3 in water with the detection limit as low as 0.05 ppm. This chemiresistive sensing system has the potential for highly efficient monitoring of ammonia and amines responsible for water pollution, eutrophication, food contamination, and industrial hazards.

Two new 28-nor-oleanane-type triterpene saponins from roots of Camellia oleifera and their cytotoxic activity.

Two new 28-nor-oleanane-type triterpene saponins, oleiferoside U (1), and oleiferoside V (2) were isolated from the 50% EtOH extract of the roots of Camellia oleifera C. Abel. Their structures were elucidated as camellenodiol 3ß-O-ß-d-galactopyranosyl-(1→2)-ß-d-xylopyranosyl-(1→2)-[ß-d-galactopyranosyl-(1→3)]-ß-d-glucuronopyranoside and camellenodiol 3ß-O-ß-d-galactopyranosyl-(1→3)-ß-d-xylopyranosyl-(1→2)-[ß-d-galactopyranosyl-(1→3)]-ß-d-glucuronopyranoside. Their chemical structures were established mainly on the basis of integrated spectroscopic techniques. In vitro, cytotoxic activities of the two new triterpene saponins were evaluated against three human tumor cell lines (A549, SMMC-7721, and MCF-7) using the MTT assay. Both of them showed a certain cytotoxic activities toward the tested cell lines and gave IC50 values in the range of 45.04-63.22 µM.

Regulation of the chemokine receptor CXCR4 and metastasis by hypoxia-inducible factor in non small cell lung cancer cell lines.

Hypoxia promotes metastatic potential of tumor cells by largely unknown mechanisms. Hypoxia inducible factor (HIF) is a heterodimeric transcription factor consisting of alpha and beta (ARNT) subunits and plays an important role in tumor microenvironment. CXCR4 is a cell surface receptor that has been shown to mediate the metastasis of various tumors. CXCR4 induction by hypoxia is dependent on both activation of HIF and transcript stabilization. To investigate the mechanisms involved in hypoxia-induced metastasis and hypoxia-mediated chemokine receptor CXCR4 expression, we used lentiviral vector mediated RNA interfering (RNAi) to knock down expression of HIF-1alpha or HIF-2alpha in two NSCLC cell lines to investigate HIF-dependent invasion, migration and adhesion. Here we show that: (1) hypoxia is an important factor in regulating CXCR4 mediated metastasis and the cells exhibited reducing invasion, adhesion and migration in response to CXCL12 after knocking down HIF. (2) HIF-1alpha and HIF-2alpha are essential for hypoxic cellular response to cancer invasion and adhesion through upregulation of CXCR4. HIF-1alpha and HIF-2alpha are playing important roles in tumor metastasis, which may offer for future intervention strategies. We also show that the lentivirus mediated RNAi technology is very effective on knocking down gene expression.