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Summary Background and Purpose Sprawling ( Swl ) is a radiation‐induced mutation which has been identified to have a nine base pair deletion in dynein heavy chain 1 (DYNC1H1: encoded by a single gene Dync1h1 ). This study is to investigate the phenotype and the underlying mechanism of the Dync1h1 mutant. Methods and Results To display the phenotype of Swl mutant mice, we examined the embryos of homozygous ( Swl/Swl ) and heterozygous ( Swl /+) mice and their postnatal dorsal root ganglion (DRG) of surviving Swl /+ mice. The Swl /+ mice could survive for a normal life span, while Swl/Swl could only survive till embryonic (E) 8.5 days. Excessive apoptosis of Swl/ + DRG neurons was revealed during E11.5–E15.5 days, and the peak rate was at E13.5 days. In vitro study of mutated DRG neurons showed impaired retrograde transport of dynein‐driven nerve growth factor (NGF). Mitochondria, another dynein‐driven cargo, demonstrated much slower retrograde transport velocity in Swl/+ neurons than in wild‐type (WT) neurons. Nevertheless, the Swl , Loa, and Cra mutations did not affect homodimerization of DYNC1H1. Conclusion The Swl/Swl mutation of Dync1h1 gene led to embryonic mal‐development and lethality, whereas the Swl/+ DRG neurons demonstrated deficient retrograde transport in dynein‐driven cargos and excessive apoptosis during mid‐ to late‐developmental stages. The underlying mechanism of the mutation may not be due to impaired homodimerization of DYNC1H1.

BACKGROUNDRAS/RAF/mitogen‐activated protein kinase activation is common in myeloid malignancies. Trametinib, a mitogen‐activated protein kinase kinase 1 (MEK1)/MEK2 inhibitor with activity against multiple myeloid cell lines at low nanomolar concentrations, was evaluated for safety and clinical activity in patients with relapsed/refractory leukemias.METHODSThis phase 1/2 study accrued patients with any relapsed/refractory leukemia in phase 1. In phase 2, this study accrued patients with relapsed/refractory acute myeloid leukemia (AML) or high‐risk myelodysplastic syndromes (MDS) with NRAS or KRAS mutations (cohort 1); patients with AML, MDS, or chronic myelomonocytic leukemia (CMML) with a RAS wild‐type mutation or an unknown mutation status (cohort 2); and patients with CMML with an NRAS or KRAS mutation (cohorts 3).RESULTSThe most commonly reported treatment‐related adverse events were diarrhea, rash, nausea, and increased alanine aminotransferase levels. The phase 2 recommended dose for Trametinib was 2 mg orally daily. The overall response rates were 20%, 3%, and 27% for cohorts 1, 2, and 3, respectively, and this indicated preferential activity among RAS‐mutated myeloid malignancies. Repeated cycles of trametinib were well tolerated with manageable or reversible toxicities; these results were similar to those of other trametinib studies.CONCLUSIONSThe selective, single‐agent activity of trametinib against RAS‐mutated myeloid malignancies validates its therapeutic potential. Combination strategies based on a better understanding of the hierarchical role of mutations and signaling in myeloid malignancies are likely to improve the response rate and duration. Cancer 2016;122:1871–9. © 2016 American Cancer Society.

ObjectiveApolipoprotein E (apoE), a major cholesterol carrier in the brain, is associated with a strong risk for Alzheimer disease. Compared to the risky APOE4 gene allele, the effects of the protective APOE2 gene allele are vastly understudied, and thus need to be further clarified.MethodsWe reviewed National Alzheimer's Coordinating Center clinical records and performed preclinical experiments using human apoE‐targeted replacement (apoE‐TR) mice, which do not show amyloid pathology.ResultsClinically, the APOE2 allele was associated with less cognitive decline during aging. This effect was also seen in subjects with little amyloid pathology, or after adjusting for Alzheimer disease‐related pathologies. In animal studies, aged apoE2‐TR mice also exhibited preserved memory function in water maze tests. Regardless, apoE2‐TR mice showed similar or greater age‐related changes in synaptic loss, neuroinflammation, and oxidative stress compared to apoE3‐TR or apoE4‐TR mice. Interestingly, apoE concentrations in the cortex, hippocampus, plasma, and cerebrospinal fluid (CSF) were positively correlated with memory performance across apoE isoforms, where apoE2‐TR mice had higher apoE levels. Moreover, apoE2‐TR mice exhibited the lowest levels of cholesterol in the cortex, despite higher levels in CSF and plasma. These cholesterol levels were associated with apoE levels and memory performance across apoE isoforms.InterpretationAPOE2 is associated with less cognitive decline during aging. This can occur independently of age‐related synaptic/neuroinflammatory changes and amyloid accumulation. Higher levels of apoE and associated cholesterol metabolism in APOE2 carriers might contribute to this protective effect. Ann Neurol 2016;79:758–774

ABSTRACT Understanding how some HIV-infected cells resist the cytotoxicity of HIV replication is crucial to enabling HIV cure efforts. HIV killing of CD4 T cells that replicate HIV can involve HIV protease-mediated cleavage of procaspase 8 to generate a fragment (Casp8p41) that directly binds and activates the mitochondrial proapoptotic protein BAK. Here, we demonstrate that Casp8p41 also binds with nanomolar affinity to the antiapoptotic protein Bcl-2, which sequesters Casp8p41 and prevents apoptosis. Further, we show that central memory CD4 T cells (T CM ) from HIV-infected individuals have heightened expression of BCL-2 relative to procaspase 8, possibly explaining the persistence of HIV-infected T CM despite generation of Casp8p41. Consistent with this hypothesis, the selective BCL-2 antagonist venetoclax induced minimal killing of uninfected CD4 T cells but markedly increased the death of CD4 T cells and diminished cell-associated HIV DNA when CD4 T cells from antiretroviral therapy (ART)-suppressed HIV patients were induced with αCD3/αCD28 to reactivate HIV ex vivo . Thus, priming CD4 T cells from ART suppressed HIV patients with a BCL-2 antagonist, followed by HIV reactivation, achieves reductions in cell-associated HIV DNA, whereas HIV reactivation alone does not. IMPORTANCE HIV infection is incurable due to a long-lived reservoir of HIV + memory CD4 T cells, and no clinically relevant interventions have been identified that reduce the number of these HIV DNA-containing cells. Since postintegration HIV replication can result in HIV protease generation of Casp8p41, which activates BAK, causing infected CD4 T cell death, we sought to determine whether this occurs in memory CD4 T cells. Here, we demonstrate that memory CD4 T cells can generate Casp8p41 and yet are intrinsically resistant to death induced by diverse stimuli, including Casp8p41. Furthermore, BCL-2 expression is relatively increased in these cells and directly binds and inhibits Casp8p41's proapoptotic effects. Antagonizing BCL-2 with venetoclax derepresses this antagonism, resulting in death, preferentially in HIV DNA containing cells, since only these cells generate Casp8p41. Thus, BCL-2 antagonism is a clinically relevant intervention with the potential to reduce HIV reservoir size in patients.

Abstract Elucidating mechanisms of chemoresistance is critical to improve cancer therapy, especially for the treatment of pancreatic ductal adenocarcinoma (PDAC). Genome-wide association studies have suggested the less studied gene HEAT repeat-containing protein 1 (HEATR1) as a possible determinant of cellular sensitivity to different chemotherapeutic drugs. In this study, we assessed this hypothesized link in PDAC, where HEATR1 expression is downregulated significantly. HEATR1 silencing in PDAC cells increased resistance to gemcitabine and other chemotherapeutics, where this effect was associated with increased AKT kinase phosphorylation at the Thr308 regulatory site. Mechanistically, HEATR1 enhanced cell responsiveness to gemcitabine by acting as a scaffold to facilitate interactions between AKT and the protein phosphatase PP2A, thereby promoting Thr308 dephosphorylation. Consistent with these findings, treatment with the AKT inhibitor triciribine sensitized HEATR1-depleted PDAC cells to gemcitabine, suggesting that this therapeutic combination may overcome gemcitabine resistance in patients with low HEATR1 expression. Clinically, we found that HEATR1 downregulation in PDAC patients was associated with increased AKT phosphorylation, poor response to tumor resection plus gemcitabine standard-of-care treatment, and shorter overall survival. Collectively, our findings establish HEATR1 as a novel regulator of AKT and a candidate predictive and prognostic indicator of drug responsiveness and outcome in PDAC patients. Cancer Res; 76(3); 572–81. ©2015 AACR.

BACKGROUNDThe objective of this study was to demonstrate that computer‐extracted image phenotypes (CEIPs) of biopsy‐proven breast cancer on magnetic resonance imaging (MRI) can accurately predict pathologic stage.METHODSThe authors used a data set of deidentified breast MRIs organized by the National Cancer Institute in The Cancer Imaging Archive. In total, 91 biopsy‐proven breast cancers were analyzed from patients who had information available on pathologic stage (stage I, n = 22; stage II, n = 58; stage III, n = 11) and surgically verified lymph node status (negative lymph nodes, n = 46; ≥ 1 positive lymph node, n = 44; no lymph nodes examined, n = 1). Tumors were characterized according to 1) radiologist‐measured size and 2) CEIP. Then, models were built that combined 2 CEIPs to predict tumor pathologic stage and lymph node involvement, and the models were evaluated in a leave‐1‐out, cross‐validation analysis with the area under the receiver operating characteristic curve (AUC) as the value of interest.RESULTSTumor size was the most powerful predictor of pathologic stage, but CEIPs that captured biologic behavior also emerged as predictive (eg, stage I and II vs stage III demonstrated an AUC of 0.83). No size measure was successful in the prediction of positive lymph nodes, but adding a CEIP that described tumor “homogeneity” significantly improved discrimination (AUC = 0.62; P = .003) compared with chance.CONCLUSIONSThe current results indicate that MRI phenotypes have promise for predicting breast cancer pathologic stage and lymph node status. Cancer 2016;122:748–757. © 2015 American Cancer Society.

SummaryAimsFibrillar aggregates of β‐amyloid protein (Aβ) are the main constituent of senile plaques and considered to be one of the causative events in the pathogenesis of Alzheimer's disease (AD). Compounds that could inhibit Aβ fibrils formation, disaggregate preformed Aβ fibrils as well as reduce their associated neurotoxicity might have therapeutic values for treating AD. In this study, the inhibitory effects of bis (heptyl)‐cognitin (B7C), a multifunctional dimer derived from tacrine, on aggregation and neurotoxicity of Aβ1‐40 were evaluated both in vitro and in vivo.MethodsThioflavin T fluorescence assay was carried out to evaluate Aβ aggregation, MTT and Hoechst‐staining assays were performed to investigate Aβ‐associated neurotoxicity. Fluorescent probe DCFH‐DA was used to estimate the accumulation of intracellular reactive oxygen stress (ROS). Morris water maze was applied to determine learning and memory deficits induced by intracerebroventricular infusion of Aβ in rats.ResultsB7C (0.1–10 μM), but not tacrine, effectively inhibited Aβ fibrils formation and disaggregated preformed Aβ fibrils following co‐incubation of B7C and Aβ monomers or preformed fibrils, respectively. In addition, B7C markedly reduced Aβ fibrils‐associated neurotoxicity in SH‐SY5Y cell line, as evidenced by the increase in cell survival, the decrease in Hoechst‐stained nuclei and in intracellular ROS. Most encouragingly, B7C (0.1 and 0.2 mg/kg), 10 times more potently than tacrine (1 and 2 mg/kg), inhibited memory impairments after intracerebroventricular infusion of Aβ in rats, as evidenced by the decrease in escape latency and the increase in the spatial bias in Morris water maze test along with upregulation of choline acetyltransferase activity and downregulation of acetylcholinesterase activity.ConclusionThese findings provide not only novel molecular insight into the potential application of B7C in treating AD, but also an effective approach for screening anti‐AD agents.

Abstract The aim of this study was to estimate the effect of exposure to secondhand tobacco smoke on the incidence of lung adenocarcinoma in situ/minimally invasive adenocarcinoma (AIS/MIA). Data from seven case–control studies participating in the International Lung Cancer Consortium (ILCCO) were pooled, resulting in 625 cases of AIS/MIA and 7,403 controls, of whom 170 cases and 3,035 controls were never smokers. Unconditional logistic regression was used to estimate adjusted ORs (ORadj) and 95% confidence intervals (CI), controlling for age, sex, race, smoking status (ever/never), and pack-years of smoking. Study center was included in the models as a random-effects intercept term. Ever versus never exposure to secondhand tobacco smoke was positively associated with AIS/MIA incidence in all subjects (ORadj = 1.48; 95% CI, 1.14–1.93) and in never smokers (ORadj = 1.45; 95% CI, 1.00–2.12). There was, however, appreciable heterogeneity of ORadj across studies (P = 0.01), and the pooled estimates were largely influenced by one large study (40% of all cases and 30% of all controls). These findings provide weak evidence for an effect of secondhand tobacco smoke exposure on AIS/MIA incidence. Further studies are needed to assess the impact of secondhand tobacco smoke exposure using the newly recommended classification of subtypes of lung adenocarcinoma. Cancer Epidemiol Biomarkers Prev; 24(12); 1902–6. ©2015 AACR.

Polylactic acid (PLA) has a long history in medical applications. Reinforced PLA has the potential to be used in the medical applications that require high mechanical strength such as coronary stents and bone fixation devices. Halloysite nanotube (HNT) has received considerable attention recently due to its tubular structure, high aspect ratio, high mechanical strength, thermal stability, biocompatibility and sustained drug releasing properties. Halloysite has been investigated in compounding with many polymers. However, the research in compounding halloysite with biodegradable materials for use in biological applications is sparse. In this study various weight fractions of HNT was compounded with the biodegradable polymer PLA using a melt compounding method. Tensile test, Fourier infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), contact angle test, scanning electron microscopy (SEM), void content and thermogravimetric analysis (TGA) were carried out to study the PLA/HNT composite. Tensile test results indicated that Young's modulus and stiffness of PLA were enhanced with the addition of HNT; FTIR spectra showed the interaction between the PLA and HNT; whereas contact angle measurements indicated that the wettability of the PLA/HNT composite was not affected by the addition of HNT. However, the thermal stability of PLA was adversely effected by the addition of HNT which may be related to the presence of voids between the polymer and matrix. Nevertheless, the reinforced PLA/HNT composite, which maintains the surface characteristics, may prove beneficial for use in biological applications. POLYM. COMPOS., 38:2166–2173, 2017. © 2015 Society of Plastics Engineers