Synthesis and Characterization of a Terminal Iron(II)-PH2 Complex and a Series of Iron(II)-PH3 Complexes.

Reported is the reaction of a series of iron(II) bisphosphine complexes with PH3 in the presence of NaBArF4 [where BArF4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate]. The iron(II) bisphosphine reagents bear two chlorides or a hydride and a chloride motif. We have isolated six different cationic terminal-bound PH3 complexes and undertaken rigorous characterization by NMR spectroscopy, single crystal X-ray diffraction, and mass spectrometry, where the PH3 often remains intact during the ionization process. Unusual bis- and tris-PH3 complexes are among the compounds isolated. Changing the monophosphine from PH3 to PMe3 results in the formation of an unusual Fe7 cluster, but with no PMe3 being ligated. Finally, by using an iron(0) source, we have provided a rare example of a terminally bound iron-PH2 complex.

Iron(II)-Catalyzed Activation of Si-N and Si-O Bonds Using Hydroboranes.

We report the activation and functionalization of Si-N bonds with pinacol borane catalyzed by a three-coordinate iron(II) ß-diketiminate complex. The reactions proceed via the mild activation of silazanes to yield useful hydrosilanes and aminoboranes. The reaction is studied by kinetic analysis, along with a detailed investigation of decomposition pathways using catecholborane as an analogue of the pinacol borane used in catalysis. We have extended the methodology to develop a polycarbosilazane depolymerization strategy, which generates hydrosilane quantitatively along with complete conversion to the Bpin-protected diamine. The analogous Si-O bond cleavage can also be achieved with heating, using silyl ether starting materials to generate hydrosilane and alkoxyborane products. Depolymerization of poly(silyl ether)s using our strategy successfully converts the polymer to 90% Bpin-protected alcohols.

Dual-AAV vector-mediated expression of MYO7A improves vestibular function in a mouse model of Usher syndrome 1B.

Usher syndrome is the most common cause of deafness-blindness in the world. Usher syndrome type 1B (USH1B) is associated with mutations in MYO7A. Patients with USH1B experience deafness, blindness, and vestibular dysfunction. In this study, we applied adeno-associated virus (AAV)-mediated gene therapy to the shaker-1 (Myo7a4626SB/4626SB) mouse, a model of USH1B. The shaker-1 mouse has a nonsense mutation in Myo7a, is profoundly deaf throughout life, and has significant vestibular dysfunction. Because of the ∼6.7-kb size of the MYO7A cDNA, a dual-AAV approach was used for gene delivery, which involves splitting human MYO7A cDNA into 5' and 3' halves and cloning them into two separate AAV8(Y733F) vectors. When MYO7A cDNA was delivered to shaker-1 inner ears using the dual-AAV approach, cochlear hair cell survival was improved. However, stereocilium organization and auditory function were not improved. In contrast, in the vestibular system, dual-AAV-mediated MYO7A delivery significantly rescued hair cell stereocilium morphology and improved vestibular function, as reflected in a reduction of circling behavior and improved vestibular sensory-evoked potential (VsEP) thresholds. Our data indicate that dual-AAV-mediated MYO7A expression improves vestibular function in shaker-1 mice and supports further development of this approach for the treatment of disabling dizziness from vestibular dysfunction in USH1B patients.

Hydroboration of aldehydes, ketones and CO2 under mild conditions mediated by iron(iii) salen complexes.

The hydroboration of aldehydes, ketones and CO2 is demonstrated using a cheap and air stable [Fe(salen)]2-µ-oxo pre-catalyst with pinacolborane (HBpin) as the reductant under mild conditions. This catalyst system chemoselectively hydroborates aldehydes over ketones and ketones over alkenes. In addition, the [Fe(salen)2]-µ-oxo pre-catalyst shows good efficacy at reducing "wet" CO2 with HBpin at room temperature.

Family life events in the first year of acute lymphoblastic leukemia therapy: a children's oncology group report.

BACKGROUND: Despite higher cure rates, childhood acute lymphoblastic leukemia (ALL) may continue to result in considerable family strain. We sought to (i) measure incidence of divorce, reduced career opportunities, changes to work hours, home relocation, and changes to family planning at one year after ALL diagnosis; and (ii) Identify family and patient factors associated with these events. PROCEDURE: We conducted a prospective cohort study of 159 children with average risk-ALL enrolled and treated on COG protocol AALL0331 at 31 selected sites. Eligibility criteria included age ≥2 years and English or Spanish comprehension. Parents completed surveys at three time points during the first 12 months of therapy. RESULTS: Parents were at significantly increased risk of loss of employment (46% vs. 9.1%, P ≤ 0.001) than peers nationally. 13% divorced/separated, 27% relocated homes, 22% decided not to have more children, 51% declined occupational opportunities, and 68% decreased work hours. In adjusted analyses, relocation correlated with less maternal education (OR: 4.27 [95% CI: 1.43-12.82]). Declining parental opportunities associated with family income <$50,000 (OR: 4.25 [95% CI: 1.50-12.02]) and child <5 years old (OR: 4.21 [95% CI: 1.73-10.25]). Deciding not to have more children correlated with smaller family size 2-3 versus 4-5 (OR: 3.62 [95% CI: 1.10-11.96]). CONCLUSION: Families experience a high incidence of major life changes in the first year of ALL treatment. Understanding these burdens helps health care providers to provide appropriate anticipatory guidance and support. No unifying factor was associated with the different family events. Ongoing follow-up is planned to measure long-term outcomes.

SpliceArray profiling of breast cancer reveals a novel variant of NCOR2/SMRT that is associated with tamoxifen resistance and control of ERα transcriptional activity.

Gene expression profiling aimed at classifying and prognosing breast cancer has yielded signatures with little, if any, concordance. However, expression arrays used in these studies do not discriminate alternate RNA splice isoforms that vary widely in cancer and may resolve this problem. In this study, we profiled splice isoforms in a panel of tamoxifen-sensitive and -resistant cell lines, defining a novel variant (BQ323636.1) of the nuclear receptor corepressor 2 (NCOR2) that was associated with tamoxifen resistance. Overexpression of this variant in a tamoxifen-sensitive cell line induced its resistance to tamoxifen. We confirmed our initial findings from cell lines in 77 breast tumors from a Chinese cohort, where BQ323636.1 expression was higher in tamoxifen-resistant patients than tamoxifen-sensitive patients. For patients who were estrogen receptor (ER)-positive and had received tamoxifen treatment, higher BQ323636.1 expression level correlated with distant metastasis. High expression level of BQ323636.1 was found to be associated with poorer overall and disease-free survival for patients who had received tamoxifen treatment. Notably, higher BQ323636.1 versus NCOR2 wild-type ratio was also associated with negative ER and progesterone receptor (PR) status, and triple-negative status (ER-/PR-/HER2- receptor status). Mechanistic investigations showed that under conditions of tamoxifen exposure, BQ323636.1 suppressed the transcriptional activity of ERα, exhibiting promoter-regulating functions. Our findings highlight a novel splice variant of the ERα corepressor NCOR2 as a candidate biomarker in breast cancer that not only predicts tamoxifen response but may be targeted to overcome tamoxifen resistance.

Interferons induce the expression of IFITM1 and IFITM3 and suppress the proliferation of rat neonatal cardiomyocytes.

Cardiovascular diseases have been one of the leading killers among the human population worldwide. During the heart development, cardiomyocytes undergo a transition from hyperplastic to hypertrophic growth with an unclear underlying mechanism. In this study, we aim to investigate how interferons differentially stimulate the interferon-inducible transmembrane (IFITM) family proteins and further be involved in the process of heart development. The expression levels of three IFITM family members, IFITM1, IFITM2, and IFITM3 were investigated during Sprague-Dawley rat myocardial development and differentiation of H9C2 cardiomyocytes. The effects of interferon-α, -ß, and -γ on DNA synthesis in H9C2 cells were also characterized. Up-regulation of IFITM1 and IFITM3 were observed during the heart development of Sprague-Dawley rat and the differentiation of H9C2 cells. Moreover, interferon-α and -ß induce the expression of IFITM3 while interferon-γ up-regulates IFITM1. Finally, interferon-α and -ß were demonstrated to inhibit DNA synthesis during H9C2 cell differentiation. Our results indicated interferons are potentially involved in the differentiation and cell proliferation during heart development.

Generation of easily accessible human kidney tubules on two-dimensional surfaces in vitro.

The generation of tissue-like structures in vitro is of major interest for various fields of research including in vitro toxicology, regenerative therapies and tissue engineering. Usually 3D matrices are used to engineer tissue-like structures in vitro, and for the generation of kidney tubules, 3D gels are employed. Kidney tubules embedded within 3D gels are difficult to access for manipulations and imaging. Here we show how large and functional human kidney tubules can be generated in vitro on 2D surfaces, without the use of 3D matrices. The mechanism used by human primary renal proximal tubule cells for tubulogenesis on 2D surfaces appears to be distinct from the mechanism employed in 3D gels, and tubulogenesis on 2D surfaces involves interactions between epithelial and mesenchymal cells. The process is induced by transforming growth factor-ß(1), and enhanced by a 3D substrate architecture. However, after triggering the process, the formation of renal tubules occurs with remarkable independence from the substrate architecture. Human proximal tubules generated on 2D surfaces typically have a length of several millimetres, and are easily accessible for manipulations and imaging, which makes them attractive for basic research and in vitro nephrotoxicology. The experimental system described also allows for in vitro studies on how primary human kidney cells regenerate renal structures after organ disruption. The finding that human kidney cells organize tissue-like structures independently from the substrate architecture has important consequences for kidney tissue engineering, and it will be important, for instance, to inhibit the process of tubulogenesis on 2D surfaces in bioartificial kidneys.