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Standley S.M.,Northwestern University | Toft D.J.,Northwestern University | Cheng H.,Northwestern University | Soukasene S.,Northwestern University | And 6 more authors.
Cancer Research | Year: 2010

Nanotechnology offers novel delivery vehicles for cancer therapeutics. Potential advantages of nanoscale platforms include improved pharmacokinetics, encapsulation of cytotoxic agents, enhanced accumulation of therapeutics in the tumor microenvironment, and improved therapeutic structures and bioactivity. Here, we report the design of a novel amphiphilic molecule that self-assembles into nanostructures for intracellular delivery of cytotoxic peptides. Specifically, a cationic α-helical (KLAKLAK)2 peptide that is known to induce cancer cell death by membrane disruption was integrated into a peptide amphiphile (PA) that self-assembles into bioactive, cylindrical nanofibers. PAs are composed of a hydrophobic alkyl tail, a β-sheet forming peptide, and a bioactive peptide that is displayed on the surface of the nanofiber after self-assembly. PA nanostructures that included (KLAKLAK) 2 were readily internalized by breast cancer cells, in contrast to the (KLAKLAK)2 peptide that on its own was not cell permeable. (KLAKLAK)2 nanostructures, but not the peptides alone, also induced breast cancer cell death by caspase-independent and Bax/Bak-independent mechanisms associated with membrane disruption. Significantly, (KLAKLAK) 2 nanostructures induced cell death more robustly in transformed breast epithelial cells than in untransformed cells, suggesting a degree of tumor selectivity. Our results provide proof-of-principle that self-assembling PAs can be rationally designed to generate nanostructures that can efficiently deliver cytotoxic peptides to cancer cells. ©2010 AACR.

Menendez J.A.,Catalan Institute of Oncology ICO | Menendez J.A.,Girona Biomedical Research Institute IDIBGI | Benboudjema L.,Evanston Northwestern Healthcare Research Institute | Vellon L.,CONICET | And 6 more authors.
Oncotarget | Year: 2015

Telomere length, shape and function depend on a complex of six core telomere-associated proteins referred to as the telosome or shelterin complex. We here demonstrate that the isoform β2 of the heregulin family of growth factors (HRGβ2) is a novel interactor of the telosome/shelterin complex in human telomeres. Analysis of protein-protein interactions using a high-throughput yeast two-hybrid (Y2H) screen identified RAP1, the only telomere protein that is conserved from yeasts to mammals, as a novel interacting partner of HRGβ2. Deletion analysis of RAP1 revealed that the linker domain, a region previously suggested to recruit negative regulators of telomere length, interacts specifically with HRGβ2. Co-immunoprecipitation and imaging experiments demonstrated that, in addition to RAP1, HRGβ2 could associate with the RAP1-associated telomeric repeat binding factor 2 (TRF2). Deletion analysis of HRGβ2 confirmed that a putative nuclear localization signal (NLS) was necessary for nuclear HRGβ2 to exert a negative regulation of telomere length whereas the N-terminus (extracellular) amino acids of HRGβ2 were sufficient to interact with RAP1/TRF2 and promote telomere shortening. Taken together, our studies identify nuclear HRGβ2 as one of the previously unknown regulators predicted to be recruited by the RAP1 linker domain to negatively regulate telomere length in human cells. Our current findings reveal that a new, but likely not the last, unexpected visitor has arrived to the "telosome/shelterin town".

Lu M.C.,University of California at Los Angeles | Lu M.C.,Center for Healthier Children | Jones L.,Healthy African American Families | Bond M.J.,Washington Hospital Center | And 5 more authors.
Ethnicity and Disease | Year: 2010

Objectives: To: 1) review the historical contexts and current profiles of father involvement in African American families; 2) identify barriers to, and supports of, involvement; 3) evaluate the effectiveness of father involvement programs; and 4) recommend directions for future research, programs, and public policies. Methods: Review of observational and interventional studies on father involvement. Results: Several historical developments (slavery, declining employment for Black men and increasing workforce participation for Black women, and welfare policies that favored single mothers) led to father absence from African American families. Today, more than two thirds of Black infants are born to unmarried mothers. Even if unmarried fathers are actively involved initially, their involvement over time declines. We identified multiple barriers to, and supports of, father involvement at multiple levels. These levels include intrapersonal (eg, human capital, attitudes and beliefs about parenting), interpersonal (eg, the father's relationships with the mother and maternal grandmother), neighborhoods and communities (eg, high unemployment and incarceration rates), cultural or societal (eg, popular cultural perceptions of Black fathers as expendable and irresponsible, racial stratification and institutionalized racism), policy (eg, Earned Income Tax Credit, Temporary Assistance for Needy Families, child support enforcement), and life-course factors (eg, father involvement by the father's father). We found strong evidence of success for several intervention programs (eg, Reducing the Risk, Teen Outreach Program, and Children's Aid Society - Carrera Program) designed to prevent formation of father-absent families, but less is known about the effectiveness of programs to encourage greater father involvement because of a lack of rigorous research design and evaluation for most programs. Conclusion: A multi-level, life-course approach is needed to strengthen the capacity of African American men to promote greater involvement in pregnancy and parenting as they become fathers.

Kornum B.R.,Stanford University | Kornum B.R.,Copenhagen University | Kawashima M.,Stanford University | Kawashima M.,University of Tokyo | And 62 more authors.
Nature Genetics | Year: 2011

Growing evidence supports the hypothesis that narcolepsy with cataplexy is an autoimmune disease. We here report genome-wide association analyses for narcolepsy with replication and fine mapping across three ethnic groups (3,406 individuals of European ancestry, 2,414 Asians and 302 African Americans). We identify a SNP in the 3ĝ€2 untranslated region of P2RY11, the purinergic receptor subtype P2Y 11 gene, which is associated with narcolepsy (rs2305795, combined P = 6.1 - 10 '10, odds ratio = 1.28, 95% CI 1.19ĝ€"1.39, n = 5689). The disease-associated allele is correlated with reduced expression of P2RY11 in CD8 + T lymphocytes (339% reduced, P = 0.003) and natural killer (NK) cells (P = 0.031), but not in other peripheral blood mononuclear cell types. The low expression variant is also associated with reduced P2RY11-mediated resistance to ATP-induced cell death in T lymphocytes (P = 0.0007) and natural killer cells (P = 0.001). These results identify P2RY11 as an important regulator of immune-cell survival, with possible implications in narcolepsy and other autoimmune diseases. © 2011 Nature America, Inc. All rights reserved.

Youmans K.L.,University of Illinois at Chicago | Tai L.M.,University of Illinois at Chicago | Stine W.B.,Evanston Northwestern Healthcare Research Institute | Stine W.B.,Abbott Laboratories | And 11 more authors.
Molecular Neurodegeneration | Year: 2012

Background: The form(s) of amyloid-β peptide (Aβ) associated with the pathology characteristic of Alzheimer's disease (AD) remains unclear. In particular, the neurotoxicity of intraneuronal Aβ accumulation is an issue of considerable controversy; even the existence of Aβ deposits within neurons has recently been challenged by Winton and co-workers. These authors purport that it is actually intraneuronal APP that is being detected by antibodies thought to be specific for Aβ. To further address this issue, an anti-Aβ antibody was developed (MOAB-2) that specifically detects Aβ, but not APP. This antibody allows for the further evaluation of the early accumulation of intraneuronal Aβ in transgenic mice with increased levels of human Aβ in 5xFAD and 3xTg mice. Results: MOAB-2 (mouse IgG 2b) is a pan-specific, high-titer antibody to Aβ residues 1-4 as demonstrated by biochemical and immunohistochemical analyses (IHC), particularly compared to 6E10 (a commonly used commercial antibody to Aβ residues 3-8). MOAB-2 did not detect APP or APP-CTFs in cell culture media/lysates (HEK-APP Sweor HEK-APP Swe/BACE1) or in brain homogenates from transgenic mice expressing 5 familial AD (FAD) mutation (5xFAD mice). Using IHC on 5xFAD brain tissue, MOAB-2 immunoreactivity co-localized with C-terminal antibodies specific for Aβ40 and Aβ42. MOAB-2 did not co-localize with either N- or C-terminal antibodies to APP. In addition, no MOAB-2-immunreactivity was observed in the brains of 5xFAD/BACE -/- mice, although significant amounts of APP were detected by N- and C-terminal antibodies to APP, as well as by 6E10. In both 5xFAD and 3xTg mouse brain tissue, MOAB-2 co-localized with cathepsin-D, a marker for acidic organelles, further evidence for intraneuronal Aβ, distinct from Aβ associated with the cell membrane. MOAB-2 demonstrated strong intraneuronal and extra-cellular immunoreactivity in 5xFAD and 3xTg mouse brain tissues. Conclusions: Both intraneuronal Aβ accumulation and extracellular Aβ deposition was demonstrated in 5xFAD mice and 3xTg mice with MOAB-2, an antibody that will help differentiate intracellular Aβ from APP. However, further investigation is required to determine whether a molecular mechanism links the presence of intraneuronal Aβ with neurotoxicity. As well, understanding the relevance of these observations to human AD patients is critical. © 2012 Youmans et al; licensee BioMed Central Ltd.

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