35 research outputs found
Preparation of Colon-Targeted Acetylharpagide Tablets and its Release Properties in vivo and in vitro
Ethno Pharmacological Relevance: Acetylharpagide is a monomeric compound extracted from Ajuga decumbens, widely used for remedying infectious and inflammatory diseases in Southern China.Aim of the Study: The present study designed and investigated the formulation of colon-targeted acetylharpagide tablets according to the dual controlled release mechanisms of time-delay and pH-sensitivity.Materials and Methods: The core tablets of acetylharpagide were coated with the material used in time-delay systems such as ethyl cellulose and suitable channeling agent, followed by pH-dependent polymers, polyacrylic resin II and III in a combination of 1:4. Furthermore, the release and absorption performance of colon-targets tables were evaluated in vitro and in vivo. In the in vitro tests, the optimized formulation was not released in simulated gastric fluid in 2 h; the release was <5% at pH 6.8 simulated intestinal fluids for 4 h; the drug was completely released within 5 h at pH 7.6 simulated colon fluid. In the in vivo tests, pharmacokinetic characteristics of the colon-targeted tablets were investigated in dogs.Results: The results indicated that the acetylharpagide tablets with the technology of colon-targeting caused delayed Tmax, prolonged absorption time, lower Cmax, and AUCINF_obs. Meanwhile, the apparent volume of distribution (Vz_F_bs) of the colon-target tablets was higher than the reference.Conclusions: These results suggested that colon-targeted acetylharpagide tablets deliver the drug to the colon. The in vitro performance of colon-targeted acetylharpagide tablet was appropriately correlated with its performance in vivo
FAK Mediates a Compensatory Survival Signal Parallel to PI3K-AKT in PTEN-Null T-ALL Cells
SummaryMutations and inactivation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) are observed in 15%–25% of cases of human T cell acute lymphoblastic leukemia (T-ALL). Pten deletion induces myeloproliferative disorders (MPDs), acute myeloid leukemia (AML), and/or T-ALL in mice. Previous studies attributed Pten-loss-related hematopoietic defects and leukemogenesis to excessive activation of phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling. Although inhibition of this signal dramatically suppresses the growth of PTEN-null T-ALL cells in vitro, treatment with inhibitors of this pathway does not cause a complete remission in vivo. Here, we report that focal adhesion kinase (Fak), a protein substrate of Pten, also contributes to T-ALL development in Pten-null mice. Inactivation of the FAK signaling pathway by either genetic or pharmacologic methods significantly sensitizes both murine and human PTEN-null T-ALL cells to PI3K/AKT/mTOR inhibition when cultured in vitro on feeder layer cells or a matrix and in vivo
Cathelicidin-BF, a Snake Cathelicidin-Derived Antimicrobial Peptide, Could Be an Excellent Therapeutic Agent for Acne Vulgaris
Cathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules in innate immunity. Cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and it is the first identified cathelicidin antimicrobial peptide in reptiles. In this study, cathelicidin-BF was found exerting strong antibacterial activities against Propionibacterium acnes. Its minimal inhibitory concentration against two strains of P. acnes was 4.7 µg/ml. Cathelicidin-BF also effectively killed other microorganisms including Staphylococcus epidermidis, which was possible pathogen for acne vulgaris. Cathelicidin-BF significantly inhibited pro-inflammatory factors secretion in human monocytic cells and P. acnes-induced O2.− production of human HaCaT keratinocyte cells. Observed by scanning electron microscopy, the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by disrupting membranes of microorganisms. The efficacy of cathelicidin-BF gel topical administering was evaluated in experimental mice skin colonization model. In vivo anti-inflammatory effects of cathelicidin-BF were confirmed by relieving P. acnes-induced mice ear swelling and granulomatous inflammation. The anti-inflammatory effects combined with potent antimicrobial activities and O2.− production inhibition activities of cathelicidin-BF indicate its potential as a novel therapeutic option for acne vulgaris
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PHF6 Somatic Mutations and Their Functional Role in the Pathophysiology of Myelodysplastic Syndromes (MDS) and Acute Myeloid Leukemia (AML)
Abstract
Recurrent somatic nonsense PHF6 mutations have been reported in patients with T-acute lymphocytic leukemia, AML and chronic myeloid leukemia in blast crisis. Germ line (GL) PHF6 mutations are responsible for Borjeson−Forssman−Lehmann syndrome (BFLS), a hereditary X-linked disorder characterized by mental retardation and dysmorphic features. PHF6 is a highly conserved 41kDa protein with ubiquitous expression in hematopoietic cells, including CD34+ cells.
We screened patients (N=1166) with myeloid neoplasms by targeted multi-amplicon deep NGS targeting all ORFs of PHF6 to determine the prevalence and distribution and molecular context of PHF6 gene alterations. In total, we identified and verified 52 cases with somatic PHF6 mutations, 32 of which were frameshift or nonsense mutations and with a strong male predominance (76%). Mutations were distributed almost equally between 2 DNA binding domains. Previously, PHF6 has been included in other screening panels (Haferlach et al. 2014 and Papaemmanuil 2013) with somatic mutations found in 24/944 and 21/738 MDS cases, respectively. SNP-array karyotyping showed that microdeletions involving the PHF6 locus were present in about 1.2% of myeloid neoplasms, but affected only female patients.
The most frequent chromosomal aberration observed in conjunction with PHF6 mutations was trisomy-8 (P=.018). The most commonly associated somatic mutations included RUNX1 (P=.001) and IDH1 (P=.008) but not IDH2 (P>.1). There was no impact on overall survival with respect to PHF6 mutant status in total or within individual risk groups (low risk (RA,RARS) vs. high-risk (RAEB1/2). Concomitant PHF6 and RUNX1 mutations were associated with particularly poor prognosis. RUNX1 mutational status correlated with PHF6 expression levels and PHF6 expression inversely correlated with RUNX1 mRNA levels. Subsequent analysis of clonal architecture using VAF calculations and serial samples for these cases suggested that PHF6 may function as a founder driver gene in 18% of cases. PHF6 variant allelic frequency (VAF) varied between disease subtypes, with the highest clonal burden found in AML patients (P<.01). Within MDS patients we also found lower expression of PHF6 mRNA in CD34+ cells in MDS overall vs. controls (P<.01), as well as lower expression of PHF6 in advanced myeloid neoplasms (P<.05). Lower expression (defined as mean+1SD of controls) was found in 12% and 23% of patients with lower- or higher- risk MDS, respectively.
Recent studies have proposed that PHF6 deficiency leads to impaired cell proliferation, cell cycle arrest at G2/M phase and DNA damage. Following shRNA knockdown, hematopoietic cell lines showed only moderately accelerated growth and increased response to growth factors, while EPO-dependent UT7, did not result in growth factor autonomy. To delineate the possible pathophysiological pathway involving PHF6, we compared transcriptional expression profiles of 5 different cell lines with shPHF6 to WT counterparts. We then studied the consequences of PHF6 knockdown on transcriptional profiles. We have found 1020 transcripts differentially expressed (with at least 1.5x change up/down) in the context of shPHF6 knock down. Concordant results among all 5 cell lines resulted in 354 genes that were upregulated and 766 that were down-regulated. Analyses with primary patient data derived from low PHF6 expressors and mutant cases found a concordance of 71 upregulated genes and 80 genes that were downregulated.
The most significant functional group of transcripts that was found to be modulated was a family belonging to ribosomal biogenesis pathway (pFDR<1x10-6). Mass spec fingerprinting found protein-protein interaction partners that were found to be dysregulated on a transcriptional level. This finding of protein interaction/transcriptional dependence might suggest feedback mechanisms on a transcriptional level.
In conclusion, our results indicate that PHF6 mutations are generally present in more aggressive types of myeloid neoplasms, frequently associated with RUNX1/IDH1 mutations. Our functional in vitro studies along with recently published reports suggest an association of PHF6 deficiency with transcriptional regulation and thereby provide a basis for a phenotype conveyed by ancestral lesions, consistent with its role as a tumor suppressor gene.
Disclosures
Sekeres: Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Makishima:The Yasuda Medical Foundation: Research Funding
N-Terminus-Mediated Degradation of ACS7 Is Negatively Regulated by Senescence Signaling to Allow Optimal Ethylene Production during Leaf Development in Arabidopsis
Senescence is the final phase of leaf development, characterized by key processes by which resources trapped in deteriorating leaves are degraded and recycled to sustain the growth of newly formed organs. As the gaseous hormone ethylene exerts a profound effect on the progression of leaf senescence, both the optimal timing and amount of its biosynthesis are essential for controlled leaf development. The rate-limiting enzyme that controls ethylene synthesis in higher plants is ACC synthase (ACS). In this study, we evaluated the production of ethylene and revealed an up-regulation of ACS7 during leaf senescence in Arabidopsis. We further showed that the promoter activity of ACS7 was maintained at a relatively high level throughout the whole rosette development process. However, the accumulation level of ACS7 protein was extremely low in the light-grown young seedlings, and it was gradually restored as plants aging. We previously demonstrated that degradation of ACS7 is regulated by its first 14 N-terminal residues, here we compared the phenotypes of transgenic Arabidopsis overexpressing a truncated ACS7 lacking the 14 residues with transgenic plants overexpressing the full-length protein. Results showed that seedlings overexpressing the truncated ACS7 exhibited a senescence phenotype much earlier than their counterparts overexpressing the full-length gene. Fusion of the 14 residues to SSPP, a PP2C-type senescence-suppressed protein phosphatase, effectively rescued the SSPP-induced suppression of rosette growth and development but had no effect on the delayed senescence. This observation further supported that N-terminus-mediated degradation of ACS7 is negatively regulated by leaf senescence signaling. All results of this study therefore suggest that ACS7 is one of the major contributors to the synthesis of ‘senescence ethylene’. And more importantly, the N-terminal 14 residue-mediated degradation of this protein is highly regulated by senescence signaling to enable plants to produce the appropriate levels of ethylene required
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U2AF1 Mutations in S34 and Q157 Create Distinct Molecular and Clinical Contexts
Abstract
Background: U2AF1 forms a heterodimer for the recognition of the 3' splice site during pre-mRNA splicing. Somatic U2AF1 mutations are present in approximately 10% of MDS patients. Most U2AF1 mutations are recurrent at 2 highly conserved hotspots, while non-canonical mutations are rare. U2AF1S34 and U2AF1Q157 mutations map within the zinc finger domains of the protein, resulting in distinct downstream effects. We have previously shown that U2AF1Q157 mutant patients have distinct splicing patterns compared to U2AF1WT with a set of misspliced targeted genes, including ARID2 and EZH2. In contrast, recent work focusing on S34 suggests a distinct subset of misspliced genes, including ATG7 (Park SM, Molecular Cell, 2016). The biological and clinical implications of these 2 distinct mutations are unknown. We investigated the differences between these mutations with respect to clinical outcomes and molecular background, including their impact on clonal architecture.
Methods: We first collected molecular and clinical data on a cohort of 1700 patients with myeloid neoplasms (median follow up 1.0 year, range 1-5 years), median age was 65 years (range, 11-93). Targeted deep sequencing of a panel of frequently mutated genes (64) was applied. Our analyses included somatic mutational patterns, clonal hierarchy, and mutational correlation of the cohort of patients with U2AF1S34 and U2AF1Q157 and those without mutations in this gene. U2AF1 mutations were found in 5% (78/1700) of patients, all of them were missense and in a heterozygous configuration.
Results: Both mutations were equally distributed in the cohort: U2AF1S34 (45%, 35/78), and U2AF1Q157 (46%, 36/78). Other mutations (Q84, E124, E152, and R156) were detected at a lower frequency (9%). We then dissected the clonal hierarchy of both U2AF1 mutations and found that 44% (34/77) were ancestral while 56% (43/77) were secondary. In MDS, most U2AF1 mutations (77%, P=.002) were dominant, while subclonal U2AF1 mutations were evenly distributed between the subentities. U2AF1S34 or U2AF1Q157 were equally likely to be dominant (21% vs. 27%; ancestral events; P=.09, respectively). Similarly, S34 and Q157 mutant clones had similar median variant allele frequencies (3-52% vs. 8-64%).
U2AF1 S34 mutant cases had similar OS to patients carrying U2AF1Q157 (N=35 vs. N=36; 10 vs. 15 months; P=.209; LogR=.65). When we compared the impact of ancestral vs. secondary U2AF1S34 and U2AF1Q157 we found that MDS patients carrying ancestral U2AF1 mutations had a shorter OS compared to MDS patients carrying secondary U2AF1 patients (N=26 vs. N=18; 13 vs. 34 months; LogR=.04). Of note, ancestral U2AF1S34 patients had shorter OS compared to ancestral U2AF1Q157 patients (13 vs.11; 10 vs.15 months; P=.03; LogR=.86).
Given these differences, we also investigated the mutational spectrum of U2AF1MUT patients. Cross sectional analysis identified that the top genes mutated in the U2AF1 mutant cohort were: ASXL1 (26%), BCOR/L1 (15%), TET2 (13%), DNMT3A and PHF6 (12%), ETV6 (10%), RUNX1 and STAG2 (9%), and SETBP1 (8%). Transcriptional factor and DNA-methylation genes were predominantly mutated in U2AF1MUT patients (35% and 24%, respectively). Exploring the association between S34/Q157 vs. other gene mutations, S34 co-occurred with BCOR/L1 mutations (P=.007, 24%), while Q157 mutations co-occurred with ASXL1 (P=.003, 44%) irrespective of their rank in the clonal hierarchy. When S34 was the dominant mutation, secondary mutations included ETV6, BCOR, and CUX1. In contrast, when Q157 was the ancestral event, secondary mutations included ASXL1 and DNMT3A. Subclonal S34 occurred in the context of ancestral RUNX1, BCOR/L1, CUX1 and DNMT3A, while subclonal Q157 followed ancestral ASXL1, EZH2, PHF6 and TET2.
Conclusion: In sum, U2AF1S34 and U2AF1Q157, consistent with their differential missplicing consequences, create a distinct molecular milieu leading to differences in clinical outcomes.
Disclosures
Makishima: The Yasuda Medical Foundation: Research Funding. Carraway:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Research Funding, Speakers Bureau; Baxalta: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Maciejewski:Celgene: Consultancy, Honoraria, Speakers Bureau; Alexion Pharmaceuticals Inc: Consultancy, Honoraria, Speakers Bureau; Apellis Pharmaceuticals Inc: Membership on an entity's Board of Directors or advisory committees
Effects of 0.2% cathelicidin-BF and clindamycin gel on <i>P. acnes</i>-induced inflammation and <i>P. acnes</i> growth <i>in vivo</i>.
<p>Left ears of mice were intradermally injected with <i>P. acnes</i> (1×10<sup>7</sup> CFU per 20 µl in PBS) to induce inflammation. Right ears of the same mice were injected with 20 µl of 0.9% salt water (vehicle). Subsequently, 0.2% cathelicidin-BF gel, 0.2% clindamycin gel or vehicle was applied on the ear skin surface of mice. (<b>A</b>) The increase in ear thickness was measured using a micro caliper before and 24 hours after the bacterial injection. (<b>B</b>) 24 hours after P. acnes injection, CFUs of P. acnes in the ear were enumerated as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0022120#s4" target="_blank">Materials and methods</a>” section. Data represent mean ± SE of five individual experiments. Cath: cathelicidin-BF; CL: clindamycin. The values for cathelicidin-BF and clindamycin were significant different from the value for the vehicle (*<i>P</i><0.05 and **<i>p</i><0.01).</p
Scanning electron micrographs of control (A), cathelicidin-BF-treated (B), and clindamycin-treated (C) <i>P. acnes</i>.
<p>The arrows indicate damage to the plasma membranes of bacteria or the intracellular inclusions efflux.</p