Glioblastoma multiforme (GBM) is a neurologically debilitating disease that culminates in death 14 to 16 months after diagnosis. An incomplete understanding of how cataloged genetic aberrations ...promote therapy resistance, combined with ineffective drug delivery to the central nervous system, has rendered GBM incurable. Functional genomics efforts have implicated several oncogenes in GBM pathogenesis but have rarely led to the implementation of targeted therapies. This is partly because many "undruggable" oncogenes cannot be targeted by small molecules or antibodies. We preclinically evaluate an RNA interference (RNAi)-based nanomedicine platform, based on spherical nucleic acid (SNA) nanoparticle conjugates, to neutralize oncogene expression in GBM. SNAs consist of gold nanoparticles covalently functionalized with densely packed, highly oriented small interfering RNA duplexes. In the absence of auxiliary transfection strategies or chemical modifications, SNAs efficiently entered primary and transformed glial cells in vitro. In vivo, the SNAs penetrated the blood-brain barrier and blood-tumor barrier to disseminate throughout xenogeneic glioma explants. SNAs targeting the oncoprotein Bcl2Like12 (Bcl2L12)--an effector caspase and p53 inhibitor overexpressed in GBM relative to normal brain and low-grade astrocytomas--were effective in knocking down endogenous Bcl2L12 mRNA and protein levels, and sensitized glioma cells toward therapy-induced apoptosis by enhancing effector caspase and p53 activity. Further, systemically delivered SNAs reduced Bcl2L12 expression in intracerebral GBM, increased intratumoral apoptosis, and reduced tumor burden and progression in xenografted mice, without adverse side effects. Thus, silencing antiapoptotic signaling using SNAs represents a new approach for systemic RNAi therapy for GBM and possibly other lethal malignancies.
Nanoscale electrode junctions have been selectively functionalized with specific oligonucleotide sequences using dip‐pen nanolithography (see picture). These sequences direct the assembly of ...electrical circuits containing 20‐ and 30‐nm‐diameter DNA‐modified nanoparticles so that junctions bridged by single nanoparticles can be realized. Different nanoparticle types can be directed to specific junctions on a single chip through solution‐phase bottom‐up assembly.
Herein, we report the synthesis of DNA‐functionalized infinite‐coordination‐polymer (ICP) nanoparticles as biocompatible gene‐regulation agents. ICP nanoparticles were synthesized from ferric nitrate ...and a ditopic 3‐hydroxy‐4‐pyridinone (HOPO) ligand bearing a pendant azide. Addition of FeIII to a solution of the ligand produced nanoparticles, which were colloidally unstable in the presence of salts. Conjugation of DNA to the FeIII–HOPO ICP particles by copper‐free click chemistry afforded colloidally stable nucleic‐acid nanoconstructs. The DNA–ICP particles, when cross‐linked through sequence‐specific hybridization, exhibited narrow, highly cooperative melting transitions consistent with dense DNA surface loading. The ability of the DNA–ICP particles to enter cells and alter protein expression was also evaluated. Our results indicate that these novel particles carry nucleic acids into mammalian cells without the need for transfection agents and are capable of efficient gene knockdown.
Iron it out: DNA‐modified infinite‐coordination‐polymer (ICP) nanoparticles were constructed by a facile method to afford biocompatible gene‐regulation agents. The iron(III)‐based ICP nanoparticles were synthesized in water and conjugated directly to oligonucleotides by a copper‐free click reaction. The resulting conjugates were capable of entering cells and effecting antisense gene regulation without transfection agents (see picture).
Schizosaccharomyces pombe Ddb1 is homologous to the mammalian DDB1 protein, which has been implicated in damaged-DNA recognition and global genomic repair. However, a recent study suggested that the ...S. pombe Ddb1 is involved in cell division and chromosomal segregation. Here, we provide evidence that the S. pombe Ddb1 is functionally linked to the replication checkpoint control gene cds1. We show that the S. pombe strain lacking ddb1 has slow growth due to delayed replication progression. Flow cytometric analysis shows an extensive heterogeneity in DNA content. Furthermore, the Δddb1 strain is hypersensitive to UV irradiation in S phase and is unable to tolerate a prolonged replication block imposed by hydroxyurea. Interestingly, the Δddb1 strain exhibits a high level of the Cds1 kinase activity during passage through S phase. Moreover, mutation of the cds1 gene relieves the defects observed in Δddb1 strain. The results suggest that many of the defects observed in Δddb1 cells are linked to an aberrant activation of Cds1, and that Ddb1 is functionally linked to Cds1.
A fibro-osseous pseudotumor (FOPT) is a rare, rapidly enlarging, benign soft-tissue neoplasm that presents with localized pain, swelling, and redness. It typically presents in the hands and much less ...frequently in the feet. FOPT is characterized histologically by foci of osseous differentiation within the proliferated fibroblasts. This must be differentiated from other benign and malignant lesions. FOPT of the toes has been described in a few reports, but recurrence, following surgical excision, is extremely rare. Here we report a young, healthy female patient who presented with a rapidly growing FOPT of the left great toe. This unusual case had recurred twice following surgical excision, all within a 2-month period of time. The lesion was again completely excised, with no recurrences at follow-ups of 18 and 36 months. In conclusion, FOPT is a rare soft tissue lesion of the toes. It features fibroblastic proliferation and osseous differentiation, which needs to be differentiated from other benign and malignant tumors. The standard treatment is complete surgical excision with an excellent prognosis.
In Dip Pen Nanolithography (DPN), arbitrary nanoscale chemical patterns can be created by the diffusion of chemicals from the tip of an atomic force microscope (AFM) probe to a surface. This paper ...describes the design, optimization, fabrication, and testing of an actuated multi-probe DPN array. The probe array consists of 10 thermal bimorph active probes made of silicon nitride and gold. The probes are 300 /spl mu/m long and the tips are spaced 100 /spl mu/m apart. An actuation current of 10 mA produces a tip deflection of 8 /spl mu/m, which is enough to remove individual tips from the surface independent of the adjacent probes. An analytical probe model is presented and used to optimize the design against several possible failure modes. The array is demonstrated by using it to simultaneously write 10 unique octadecanethiol patterns on a gold surface. Pattern linewidth as small as 80 nm has been created at a maximum write speed of 20 /spl mu/m/sec. By writing multiple, distinctly different patterns in parallel, this device provides a significant improvement in throughput and flexibility over conventional AFM probes in the DPN process.
We report on the development of a nanoplotter that consists of an array of microfabricated probes for parallel dip-pen nanolithography. Two types of devices have been developed using ...microelectromechanical systems micromachining technology. The first consists of 32 silicon nitride cantilevers separated by 100 microns, while the second consists of eight boron-doped silicon tips separated by 310 microns. The former offers writing and imaging capabilities, but is challenged with respect to tip sharpness. The latter offers smaller linewidths and increased imaging capabilities at the expense of probe density. Parallel generation of nanoscopic monolayer patterns with a minimum linewidth of 60 nm has been demonstrated using an eight-pen microfabricated probe array. (Author)
Conjugated estrogens/bazedoxifene (CE/BZA) reduced menopause-related hot flashes (HFs) in the Selective estrogens, Menopause, And Response to Therapy (SMART) trials. This post hoc pooled analysis of ...SMART-1 and -2 further characterized effects of CE/BZA on HFs in the overall population and patient subgroups.
Data from two randomized, double-blind, placebo- and active-controlled, phase 3 studies were pooled for nonhysterectomized postmenopausal women with moderate/severe HFs given CE 0.45 mg/BZA 20 mg, CE 0.625 mg/BZA 20 mg, or placebo for 12 weeks. HF frequency and severity were assessed by daily diary.
The pooled analysis included 403 participants. At 12 weeks, CE 0.45 mg/BZA 20 mg and CE 0.625 mg/BZA 20 mg significantly (all p < 0.001) decreased moderate/severe HF frequency versus placebo (-7.9, -8.2, -4.1), reduced adjusted average daily HF severity score versus placebo (-1.0, -1.3, -0.3), increased the percentage of women who had a ≥50% (81.2%,87.1%, 50.6%) and ≥75% (62.4%, 74.8%, 26.4%) reduction from baseline in daily frequency of moderate/severe HFs, increased the percentage with ≥50% (38.3%, 58.1%, 11.0%) and ≥75% (24.2%, 38.1%, 5.5%) reductions in average daily HF severity score, and improved MENQOL vasomotor function versus placebo (adjusted mean change-3.08, -3.69, -1.37). CE/BZA was significantly more effective than placebo irrespective of time since menopause, with some evidence of a lower placebo response in women in later menopause (>5 years) versus early menopause (≤5 years).
CE/BZA effectively reduces moderate/severe HFs in postmenopausal women. NCT#'s: NCT00675688; NCT00234819.
Herein, we report the synthesis of DNA‐functionalized infinite‐coordination‐polymer (ICP) nanoparticles as biocompatible gene‐regulation agents. ICP nanoparticles were synthesized from ferric nitrate ...and a ditopic 3‐hydroxy‐4‐pyridinone (HOPO) ligand bearing a pendant azide. Addition of FeIII to a solution of the ligand produced nanoparticles, which were colloidally unstable in the presence of salts. Conjugation of DNA to the FeIII–HOPO ICP particles by copper‐free click chemistry afforded colloidally stable nucleic‐acid nanoconstructs. The DNA–ICP particles, when cross‐linked through sequence‐specific hybridization, exhibited narrow, highly cooperative melting transitions consistent with dense DNA surface loading. The ability of the DNA–ICP particles to enter cells and alter protein expression was also evaluated. Our results indicate that these novel particles carry nucleic acids into mammalian cells without the need for transfection agents and are capable of efficient gene knockdown.
DNA‐modifizierte Nanopartikel aus kontinuierlichen Koordinationspolymeren (ICPs) wurden durch eine einfache Methode synthetisiert, um biokompatible Genregulatoren zu erhalten. Die Eisen(III)‐basierten ICP‐Nanopartikel wurden in Wasser synthetisiert und durch eine kupferfreie Klickreaktion direkt an Oligonukleotide konjugiert. Die Konjugate können in Zellen eintreten und ohne Transfektionsagentien die Genregulation von Antisense‐Genen bewirken.
The cover picture shows a schematic representation of a nanoscale tunnel junction circuit formed when a DNA‐functionalized gold nanoparticle is directed between two metallic electrodes (a ...field‐emission SEM image is shown in the inset). The background displays an electron microscopy image of a device containing such junctions for potential use as a biosensor. Such a combination of biology, chemistry, engineering, and materials science serves as a model for the interdisciplinary character that
Small
exemplifies. For more information, please refer to the Communication by C. A. Mirkin and co‐workers on page 64 ff. The authors thank Yeechi Chen for the cover design.
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