Recurrent gross mutations of the PTEN tumor suppressor gene in breast cancers with deficient DSB repair

Basal-like breast cancer (BBC) is a subtype of breast cancer with poor prognosis. Inherited mutations of BRCA1, a cancer susceptibility gene involved in double-strand DNA break (DSB) repair, lead to breast cancers that are nearly always of the BBC subtype; however, the precise molecular lesions and oncogenic consequences of BRCA1 dysfunction are poorly understood. Here we show that heterozygous inactivation of the tumor suppressor gene Pten leads to the formation of basal-like mammary tumors in mice, and that loss of PTEN expression is significantly associated with the BBC subtype in human sporadic and BRCA1-associated hereditary breast cancers. In addition, we identify frequent gross PTEN mutations, involving intragenic chromosome breaks, inversions, deletions and micro copy number aberrations, specifically in BRCA1-deficient tumors. These data provide an example of a specific and recurrent oncogenic consequence of BRCA1-dependent dysfunction in DNA repair and provide insight into the pathogenesis of BBC with therapeutic implications. These findings also argue that obtaining an accurate census of genes mutated in cancer will require a systematic examination for gross gene rearrangements, particularly in tumors with deficient DSB repair

Three dimensional cellular architecture of sulfur doped graphene: self-standing electrode for flexible supercapacitors, lithium ion and sodium ion batteries

Tailoring the planar morphology of graphene and the generation of electron-dense active sites on its surface by heteroatom doping is one potential approach to enhance the charge storage performance of graphene based electrode materials. Herein, we have reported the preparation of a three-dimensional self-standing cellular architecture as sulfur-doped graphene foam (SGF) by using the simple self-assembly of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) polymer chains on graphene oxide followed by thermal treatment. Successful homogeneous sulfur doping in a three-dimensional (3D) framework of graphene allowed the material to have a large surface area with bulk electroactive regions on the surface for better interfacial contact with electrolyte ions and hence resulted in unprecedented energy storage capability in a flexible aqueous symmetric supercapacitor (367 F g−1 at 1 A g−1), a lithium ion battery (1697 mA h g−1 at 100 mA g−1), and a sodium ion battery (472 mA h g−1 at 50 mA g−1) as a binder-free electrode material. The outstanding electrochemical performance of the material demonstrates the potential of this synthesis approach for various heteroatom-doped self-standing nano-carbon monoliths on a small as well as a large scale for high-performance energy device fabrication for the advancement of modern electronic devices

Nanoarchitectured Nitrogen-Doped Graphene/Carbon Nanotube as High Performance Electrodes for Solid State Supercapacitors, Capacitive Deionization, Li-Ion Battery, and Metal-Free Bifunctional Electrocatalysis

A three-dimensional nanostructured nitrogen-doped graphene/carbon nanotube composite has been synthesized via a thermal annealing process, using the high surface attachment properties of uric acid (solid nitrogen precursor) with graphene oxide and oxidized multiwalled carbon nanotube. In the synthesis procedures, the attachment of uric acid to graphene oxide surfaces and the oxidized multiwalled carbon nanotubes via hydrogen bonding and electrostatic forces in the solution leads to a lamellar nanostructure during thermal annealing by the proper insertion of carbon nanotubes in graphene layers with nitrogen doping. The resultant composite has good atomic percentage of N (11.2 at. %) and shows superior electrochemical energy storage and conversion properties compared with nitrogen-doped graphene only and physically mixed nitrogen-doped graphene and nitrogen-doped carbon nanotube samples. The composite exhibits high gravimetric and volumetric capacitance (324 F g-1 at a current density of 1 A g-1) as electrode in solid-state supercapacitors, superior capacitive deionization (440 F g-1 at a current density of 1 A g-1) in 1 M sodium chloride solution, and as high-performance anode in lithium-ion batteries (1150 mAh g-1 at 0.1 A g-1) with long-term cycling stability. In addition, the composite demonstrates efficient metal-free bifunctional electrocatalysis toward the oxygen reduction and evolution reactions, comparable with the commercial electrocatalysts