Novel therapeutic strategies are needed to address the emerging problem of imatinib resistance. The histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) is being evaluated for imatinib-resistant chronic myelogenous leukemia (CML) and has multiple cellular effects, including the induction of autophagy and apoptosis. Considering that autophagy may promote cancer cell survival, we hypothesized that disrupting autophagy would augment the anticancer activity of SAHA. Here we report that drugs that disrupt the autophagy pathway dramatically augment the antineoplastic effects of SAHA in CML cell lines and primary CML cells expressing wild-type and imatinib-resistant mutant forms of BcrAbl, including T315I. This regimen has selectivity for malignant cells and its efficacy was not diminished by impairing p53 function, another contributing factor in imatinib resistance. IntroductionImatinib (Gleevec; STI-571), a targeted competitive inhibitor of the Bcr-Abl tyrosine kinase, revolutionized the clinical treatment of chronic myelogenous leukemia (CML). 1 However, acquired imatinib resistance during the accelerated and blast crisis phases of the disease is an emerging problem and has been linked to gene amplification, to point mutations in Bcr-Abl that impede drug binding or structurally preclude adoption of the inactive conformation, and to loss of p53 function. [2][3][4] Two novel inhibitors of Bcr-Abl, dasatinib and nilotinib, have been evaluated to address this problem. 5,6 Both agents produce clinical responses in many imatinib-refractory patients but not in those carrying the most drug-resistant T315I mutation, which confers cross-resistance to nilotinib and dasatinib. 7,8 The lack of effective therapeutic regimens for T315I patients thus highlights the dire need for novel therapeutic strategies that are effective in treating these patients.Histone deacetylase (HDAC) inhibitors represent a novel class of anticancer agents currently under investigation in preclinical models and in phase 1/2 clinical trials. [9][10][11][12] Suberoylanilide hydroxamic acid (SAHA) is an orally bioavailable, well-tolerated pan-HDAC inhibitor with anticancer activity in hematologic and solid malignancies. 12,13 SAHA's anticancer effects have been linked to the generation of reactive oxygen species (ROS) and to the induction of apoptosis, growth arrest, polyploidy, and autophagy. 14-17 Whether SAHA's ability to augment autophagy affects its anticancer activity remains unclear. Here we tested the hypotheses that disruption of the autophagy pathway would significantly enhance the anticancer activity of SAHA and that this would prove effective in killing imatinib-resistant CML. Patients, materials, and methods Cells and cell cultureBa/F3 cells and Ba/F3 cells engineered to express comparable levels of wild-type (p210) and mutant forms of Bcr-Abl (E255K, M351T, and T315I) were maintained as previously described. 2 K562 and LAMA 84 CML cells were maintained in RPMI-1640 media with 10% heat-inactivated fetal bovine serum at 3...

These data provide new evidence of a potential role for KE strength asymmetries in the symptomatic fatigue and physical dysfunction of persons with MS, possibly through an effect on postural stability.

Reduced levels of the cyclin‐dependent kinase inhibitor p27Kip1 connote poor prognosis in cancer. In human Burkitt lymphoma and in precancerous B cells and lymphomas arising in Eμ‐Myc transgenic mice, p27Kip1 expression is markedly reduced. We show that the transcription of the Cks1 component of the SCFSkp2 complex that is necessary for p27Kip1 ubiquitylation and degradation is induced by Myc. Further, Cks1 expression is elevated in precancerous Eμ‐Myc B cells, and high levels of Cks1 are also a hallmark of Eμ‐Myc lymphoma and of human Burkitt lymphoma. Finally, loss of Cks1 in Eμ‐Myc B cells elevates p27Kip1 levels, reduces proliferation and markedly delays lymphoma development and dissemination of disease. Therefore, Myc suppresses p27Kip1 expression, accelerates cell proliferation and promotes tumorigenesis at least in part through its ability to selectively induce Cks1.

Aging of skeletal muscle is often accompanied by muscle atrophy and it appears that apoptosis plays an important role in this process. The detailed mechanism(s) is not completely understood, however. In this study, we examined expression of the apoptosis regulatory proteins as well as the heat shock proteins, which have been shown to modulate the apoptotic process in certain cell types, in order to more completely elucidate apoptotic signaling in aged skeletal muscle. To more specifically identify alterations that are likely to be the result of aging, we compared 16-month-old middle-aged (MD) and 29-month-old senescent (SE) male Fischer 344 x Brown Norway rats in our study. Our results show that the degree of DNA laddering was higher in SE compared to MD rats. Using total tissue homogenates we examined the level of expression of several apoptosis-related proteins in two categories: mitochondria-associated proteins and caspases. Of the mitochondria-associated proteins, the levels of p53 showed a significant increase in SE compared to MD rats. There was also a significant increase in the expression of Bax, Bcl-2 and Apaf-1 in SE rats over that of MD rats; cytochrome c and AIF levels remained unchanged, however. Regarding the caspases, there were increases in the levels of pro-caspases-12 and -7 and cleaved caspase-9, although the levels of pro- and cleaved caspase-3 as well as cleaved caspase-12 remained unchanged. Furthermore, our results showed significant increases in HSP27, HSP60, and the inducible HSP70. These data show that in rat skeletal muscle increased apoptosis occurs between middle-age and senescence, indicating an aging-related increase in apoptosis in skeletal muscle. The involvement of different apoptotic pathways in the aging process is suggested by the selective alterations in the apoptosis regulatory proteins. The increased expression of the HSPs suggests a relationship between HSPs and the aging-related apoptotic process.

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T helper-2 (T H 2)-bias, the propensity of naive CD4 + T cells to differentiate into interleukin 4 (IL-4) secreting T H 2 cells, is a genetic trait impacting infectious, autoimmune and allergic disease susceptibility. T H 2-bias correlates with the amount of IL-4 initially secreted by newly activated T H cells that feeds back positively through the IL-4R-STAT6-GATA3 pathway to drive T H 2 development. Here, we identify Mina, a JmjC family member, as a genetic determinant of T H 2-bias. Mina specifically bound to and repressed the Il4 promoter. Mina overexpression in transgenic mice impaired Il4 expression, while its knockdown in primary CD4 + T cells led to Il4 derepression. Together, these findings provide mechanistic insight into an Il4 regulatory pathway controlling T H differentiation and genetic variation in T H 2-bias. Naive CD4 + T cells are multipotent sentinels of the immune system, poised to respond to instructive signals from antigen-presenting cells by differentiating into distinct effector cell lineages. These include T helper (T H ) 1 and T H 2 cells, differentially adapted for the control, respectively, of intra-and extracellular pathogens, in part via developmentally acquired potential for high expression of distinct cytokine genes 1 . Dysregulated CD4 + T cell development can promote susceptibility to infectious, autoimmune and allergic disease [2][3][4][5][6][7][8][9] .Interleukin 4 (IL-4) [http://www.signaling-gateway.org/molecule/query?afcsid=A001262], the canonical T H 2 effector cytokine, is also a critical developmental determinant, promoting Accession codesThe microarray data are deposited in RCAI RefDIC (URL: http://refdic.rcai.riken.jp/welcome.cgi) 50 under the following accession codes: RMSPTB007001 and RMSPTB008001. 11,12 to promote the differentiation of T H 2 cells possessing the capacity to secrete copious amounts of IL-4 10, 13-18 . Thus, regulation of autocrine IL-4 expression by activated T H cells is a key control point in T helper cell lineage commitment. Nonetheless, the molecular mechanism underlying this regulation is incompletely understood. Author contributions NIH Public AccessT H 2-bias is a complex genetic trait characterizing variation in the propensity of naive T H cells to differentiate into T H 2 (as opposed to T H 1) cells. T H 2-bias, measured experimentally as the amount of IL-4 produced by effector CD4 + T cells differentiated in vitro from naive T H cells activated under 'neutral' conditions (no exogenous cytokines added, except IL-2, and cultured without cytokine-specific antibodies), varies over 50-fold from the highproducer phenotype of BALB/c mice to the low-producer phenotype of B10.D2 mice and correlates with susceptibility to T H 2-dependent diseases such as bronchial asthma and leishmaniasis [14][15][16][19][20][21][22] . Various cellular mechanisms have been suggested as the basis for T H 2-bias, including variation in the sensitivity to prostaglandin 2 (PGE 2 )-dependent inhibition of interferon-γ (IFN-γ) production 23 , the timing of IL-1...

These results indicate that simulated hypoxia during HRC exercise reduce blood oxygenation, pH, and HCO and increased blood lactate ultimately decreasing muscular performance.

Vasoactive intestinal peptide (VIP) is known to induce histamine release in human skin and to include a nitric oxide (NO)-dependent dilation in several other vascular beds. However, the relative contribution of histamine and NO to VIP-mediated vasodilation in human skin is unknown. Forty-three subjects volunteered to participate in two studies designed to examine the mechanism of VIP-mediated vasodilation in human skin. Study 1 examined the contribution of NO in the skin blood flow response to eight doses of VIP ranging from 25 to 800 pmol. In addition, study 1 examined a specific role for NO in VIP-mediated dilation. Study 2 examined the relative contribution of NO and histamine to VIP-mediated dilation via H1 and H2 histamine receptors. Infusions were administered to skin sites via intradermal microdialysis. Red blood cell flux was measured by using laser-Doppler flowmetry (LDF), and cutaneous vascular conductance (CVC; LDF/mean arterial pressure) was calculated and normalized to maximal vasodilation. VIP-mediated vasodilation includes a NO-dependent component at doses above 100 pmol, where NO synthase inhibition significantly attenuates CVC (P < 0.05). Inhibition of H1 receptors attenuates the rise in CVC to exogenous VIP (P < 0.05); however, combined H1-receptor inhibition and NO synthase inhibition further reduced VIP-mediated vasodilation compared with either H1 inhibition or NO synthase inhibition alone (P < 0.05). In contrast to H1-receptor inhibition, H2-receptor inhibition did not affect vasodilation to exogenous VIP. Thus, in human skin, VIP-mediated vasodilation includes a NO-dependent component that could not be explained by H1- and H2-receptor activation.