Transitional cell carcinoma (TCC) is the most common type of bladder cancer. Here we sequenced the exomes of nine individuals with TCC and screened all the somatically mutated genes in a prevalence set of 88 additional individuals with TCC with different tumor stages and grades. In our study, we discovered a variety of genes previously unknown to be mutated in TCC. Notably, we identified genetic aberrations of the chromatin remodeling genes (UTX, MLL-MLL3, CREBBP-EP300, NCOR1, ARID1A and CHD6) in 59% of our 97 subjects with TCC. Of these genes, we showed UTX to be altered substantially more frequently in tumors of low stages and grades, highlighting its potential role in the classification and diagnosis of bladder cancer. Our results provide an overview of the genetic basis of TCC and suggest that aberration of chromatin regulation might be a hallmark of bladder cancer.
We sequenced whole exomes of ten clear cell renal cell carcinomas (ccRCCs) and performed a screen of ∼1,100 genes in 88 additional ccRCCs, from which we discovered 12 previously unidentified genes mutated at elevated frequencies in ccRCC. Notably, we detected frequent mutations in the ubiquitin-mediated proteolysis pathway (UMPP), and alterations in the UMPP were significantly associated with overexpression of HIF1α and HIF2α in the tumors (P = 0.01 and 0.04, respectively). Our findings highlight the potential contribution of UMPP to ccRCC tumorigenesis through the activation of the hypoxia regulatory network.
Co-crystallization of polymers with different configurations/tacticities provides access to materials with enhanced performance. The stereocomplexation of isotactic poly(L-lactide) and poly(D-lactide) has led to improved properties compared with each homochiral material. Herein, we report the preparation of stereocomplex micelles from a mixture of poly(L-lactide)-b-poly(acrylic acid) and poly(D-lactide)-b-poly(acrylic acid) diblock copolymers in water via crystallization-driven self-assembly. During the formation of these stereocomplex micelles, an unexpected morphological transition results in the formation of dense crystalline spherical micelles rather than cylinders. Furthermore, mixture of cylinders with opposite homochirality in either THF/H2O mixtures or in pure water at 65 °C leads to disassembly into stereocomplexed spherical micelles. Similarly, a transition is also observed in a related PEO-b-PLLA/PEO-b-PDLA system, demonstrating wider applicability. This new mechanism for morphological reorganization, through competitive crystallization and stereocomplexation and without the requirement for an external stimulus, allows for new opportunities in controlled release and delivery applications.
A series of poly(L-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) diblock copolymers with a range of hydrophobic or hydrophilic block lengths were designed in order to tune the size of the resultant cylindrical micelles using a crystallization-driven self-assembly (CDSA) approach. The precursor poly(L-lactide)-b-poly(tetrahydropyran acrylate) (PLLA-b-PTHPA) was synthesized by a combination of ring-opening polymerization (ROP) and reversible additionfragmentation chain transfer (RAFT) polymerization. The CDSA process was carried out in a tetrahydrofuran/water (THF/H 2 O) mixture during the hydrolysis of PTHPA block at 65 °C using an evaporation method. A majority of PLLA-b-PAA diblock copolymers resulted in the formation of cylindrical micelles with narrow size distributions (L w /L n < 1.30) as determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Furthermore, the length of PLLA block was found to control the length of the resultant cylindrical micelles while the length of PAA block governed their widths. Synchrotron small-angle X-ray scattering (SAXS) further proved that the length increase of these cylinders was a consequence of the decreasing PLLA block lengths. The crystalline core nature of these cylinders was characterized by wide-angle X-ray diffraction (WAXD), and the relative core crystallinity was calculated to compare different samples. Both the hydrophobic weight fraction and the relative core crystallinity were found to determine the geometry of the formed PLLA-b-PAA cylindrical micelles. Finally, changing the pH conditions of the CDSA process was found to have no significant effect on tuning the resultant dimensions of the cylinders.
The shells of various poly(dl-lactide)-b-poly(acrylic acid) (PDLLA-b-PAA) spherical micelles and poly(l-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) cylindrical micelles were functionalized with mannose to yield glyco-nanoparticles (GNPs) with different shapes and dimensions. All of these GNPs were shown to have good biocompatibility (up to 1 mg/mL). Cellular uptake experiments using RAW 264.7 have shown that the spherical GNPs were internalized to a much greater extent than the cylindrical GNPs and such a phenomenon was attributed to their different endocytosis pathways. It was demonstrated that spherical GNPs were internalized based on clathrin- and caveolin-mediated endocytosis while cylindrical GNPs mainly depended on clathrin-mediated endocytosis. We also found that longer cylindrical GNPs (Ln × Wn = 215 × 47 nm) can induce an inflammatory response (specifically interleukin 6) more efficiently than shorter cylindrical GNPs (Ln × Wn = 99 × 50 nm) and spherical GNPs (Dn = 46 nm).
The mechanisms of axonal and neuronal degeneration causing visual and neurologic disability in multiple sclerosis are poorly understood. Here we explored the contribution of mitochondria to neurodegeneration in the experimental autoimmune encephalomyelitis animal model of multiple sclerosis. Oxidative injury to the murine mitochondrion preceded the infiltration of inflammatory cells, classically heralded as the mediators of demyelination and axonal injury by transection. Nitration of mitochondrial proteins affected key subunits of complexes I and IV of the respiratory chain and a chaperone critical to the stabilization and translocation of proteins into the organelle. Oxidative products were associated with loss of mitochondrial membrane potential and apoptotic cell death. Reductions in the rate of synthesis of adenosine triphosphate were severe and even greater than those associated with disorders caused by mutated mitochondrial DNA. Mitochondrial vacuolization, swelling, and dissolution of cristae occurred in axons as early as 3 days after sensitization for experimental autoimmune encephalomyelitis. Our findings implicate mitochondrial dysfunction induced by protein inactivation and mediated by oxidative stress initiates a cascade of molecular events leading to apoptosis and neurodegeneration in experimental autoimmune encephalomyelitis that is not mediated by inflammatory cells.
The Hsp90 chaperone machine is required for the folding, activation and/or stabilization of more than 50 proteins directly related to malignant progression. Hsp90 contains small molecule binding sites at both its N- and C-terminal domains, however, limited structural and biochemical data regarding the C-terminal binding site is available. In this report, the small molecule binding site in the Hsp90 C-terminal domain was revealed by protease fingerprinting and photoaffinity labeling utilizing LC-MS/MS. The identified site was characterized by generation of a homology model for hHsp90α using the SAXS open structure of HtpG and docking the bioactive conformation of NB into the generated model. The resulting model for the bioactive conformation of NB bound to Hsp90α is presented herein.
Amelioration of mitochondrial oxidative stress by SOD2 gene delivery may be a therapeutic strategy for suppressing neurodegeneration in optic neuritis.
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