Cellular localization, accumulation and trafficking of double-walled carbon nanotubes in human prostate cancer cells

Carbon nanotubes (CNTs) are at present being considered as potential nanovectors with the ability to deliver therapeutic cargoes into living cells. Previous studies established the ability of CNTs to enter cells and their therapeutic utility, but an appreciation of global intracellular trafficking associated with their cellular distribution has yet to be described. Despite the many aspects of the uptake mechanism of CNTs being studied, only a few studies have investigated internalization and fate of CNTs inside cells in detail. In the present study, intracellular localization and trafficking of RNA-wrapped, oxidized double-walled CNTs (oxDWNT–RNA) is presented. Fixed cells, previously exposed to oxDWNT–RNA, were subjected to immunocytochemical analysis using antibodies specific to proteins implicated in endocytosis; moreover cell compartment markers and pharmacological inhibitory conditions were also employed in this study. Our results revealed that an endocytic pathway is involved in the internalization of oxDWNT–RNA. The nanotubes were found in clathrin-coated vesicles, after which they appear to be sorted in early endosomes, followed by vesicular maturation, become located in lysosomes. Furthermore, we observed co-localization of oxDWNT–RNA with the small GTP-binding protein (Rab 11), involved in their recycling back to the plasma membrane via endosomes from the trans-golgi network

A long view of liberal peace and its crisis

The ‘crisis’ of liberal peace has generated considerable debate in International Relations. However, analysis is inhibited by a shared set of spatial, cultural and temporal assumptions that rest on and reproduce a problematic separation between self-evident ‘liberal’ and ‘non-liberal’ worlds, and locates the crisis in presentist terms of the latter’s resistance to the former’s expansion. By contrast, this article argues that efforts to advance liberal rule have always been interwoven with processes of alternative order-making, and in this way are actively integral, not external, to the generation of the subjectivities, contestations, violence and rival social orders that are then apprehended as self-evident obstacles and threats to liberal peace and as characteristic of its periphery. Making visible these intimate relations of co-constitution elided by representations of liberal peace and its crisis requires a long view and an analytical frame that encompasses both liberalism and its others in the world. The argument is developed using a Foucauldian governmentality framework and illustrated with reference to Sri Lanka

Paclitaxel sensitivity of ovarian cancer can be enhanced by knocking down pairs of kinases that regulate MAP4 phosphorylation and microtubule stability

Purpose: Most patients with ovarian cancer receive paclitaxel chemotherapy, but less than half respond. Pre-treatment microtubule stability correlates with paclitaxel response in ovarian cancer cell lines. Microtubule stability can be increased by depletion of individual kinases. As microtubule stability can be regulated by phosphorylation of microtubule-associated proteins (MAPs), we reasoned that depletion of pairs of kinases that regulate phosphorylation of MAPs could induce microtubule stabilization and paclitaxel sensitization. Experimental Design: Fourteen kinases known to regulate paclitaxel sensitivity were depleted individually in 12 well-characterized ovarian cancer cell lines before measuring proliferation in the presence or absence of paclitaxel. Similar studies were performed by depleting all possible pairs of kinases in six ovarian cancer cell lines. Pairs that enhanced paclitaxel sensitivity across multiple cell lines were studied in depth in cell culture and in two xenograft models. Results: Transfection of siRNA against 10 of the 14 kinases enhanced paclitaxel sensitivity in at least six of 12 cell lines. Dual knockdown of IKBKB/STK39 or EDN2/TBK1 enhanced paclitaxel sensitivity more than silencing single kinases. Sequential knockdown was superior to concurrent knockdown. Dual silencing of IKBKB/STK39 or EDN2/TBK1 stabilized microtubules by inhibiting phosphorylation of p38 and MAP4, inducing apoptosis and blocking cell cycle more effectively than silencing individual kinases. Knockdown of IKBKB/STK39 or EDN2/TBK1 enhanced paclitaxel sensitivity in two ovarian xenograft models. Conclusions: Sequential knockdown of dual kinases increased microtubule stability by decreasing p38-mediated phosphorylation of MAP4 and enhanced response to paclitaxel in ovarian cancer cell lines and xenografts, suggesting a strategy to improve primary therapy

Maternal Embryonic Leucine Zipper Kinase is Associated with Metastasis in Triple-negative Breast Cancer

UNLABELLED: Triple-negative breast cancer (TNBC) has high relapse and metastasis rates and a high proportion of cancer stem-like cells (CSC), which possess self-renewal and tumor initiation capacity. MELK (maternal embryonic leucine zipper kinase), a protein kinase of the Snf1/AMPK kinase family, is known to promote CSC maintenance and malignant transformation. However, the role of MELK in TNBC metastasis is unknown; we sought to address this in the current study. We found that SIGNIFICANCE: These findings indicate that MELK is a driver of aggressiveness and metastasis in TNBC

Buddhist extremism, anti-Muslim violence and civil war legacies in Sri Lanka

A post-civil war country may cease military activity, but the social rupture impacts political discourse and ethnic relations, and can lead to collective violence against minorities. Sri Lanka has witnessed multiple examples of anti-Muslim sentiment and violence since the civil war termination, most infamously in 2014 when ethnic riots affected large numbers of people. Buddhist monks appeared to play a prominent role. The lengthy war and ethnonationalist ideologies have produced politico-religious shifts associated with ‘Buddhist extremism’, implicated in these riots and other aggressions. This paper uses interview data to explore the question: what causal mechanisms link post-civil war and extremist ideologies, and how this can lead to ethnic rioting. Interview respondents argue that promoting a monolithic national identity in a heterogeneous country enhances divisions, which can be politically expedient. An outright war victory, militarization of society and lack of peacebuilding sustain ethnic tensions that can be mobilized for further anti-minority violence

Comparative evaluation of INNO-LiPA HBV assay, direct DNA sequencing and subtractive PCR-RFLP for genotyping of clinical HBV isolates

Genotypes (A to H) of hepatitis B virus (HBV) influence liver disease progression and response to antiviral therapy in HBV-infected patients. Several methods have been developed for rapid genotyping of HBV strains. However, some of these methods may not be suitable for developing countries. The performance of INNO-LiPA HBV Genotyping assay (LiPA), direct DNA sequencing and subtractive PCR-RFLP of genotype-specific HBV genome regions were evaluated for accurately determining the HBV genotypes by analyzing sera (n = 80) samples from chronic HBV patients. Both, LiPA and DNA sequencing identified 63, 4 and 13 HBV strains as belonging to genotype D, genotype A and mixed genotype A and D, respectively. On the contrary, the PCR-RFLP-based method correctly identified all 4 genotype A but only 56 of 63 genotype D strains. Seven genotype D strains yielded indeterminate results. DNA sequence comparisons showed that a single nucleotide change in the target region generated an additional restriction site for Nla IV that compromised the accuracy of this method. Furthermore, all the mixed genotype A and D strains were identified only as genotype A strains. The data show that the PCR-RFLP-based method incorrectly identified some genotype D strains and failed to identify mixed genotype infections while LiPA and DNA sequencing yielded accurate results

Genotyping the hepatitis B virus with a fragment of the HBV DNA polymerase gene in Shenyang, China

The hepatitis B virus (HBV) has been classified into eight genotypes (A-H) based on intergenotypic divergence of at least 8% in the complete nucleotide sequence or more than 4% in the S gene. To facilitate the investigation of the relationship between the efficacy of drug treatment and the mutation with specific genotype of HBV, we have established a new genotyping strategy based on a fragment of the HBV DNA polymerase gene. Pairwise sequence and phylogenetic analyses were performed using CLUSTAL V (DNASTAR) on the eight (A-H) standard full-length nucleotide sequences of HBV DNA from GenBank (NCBI) and the corresponding semi-nested PCR products from the HBV DNA polymerase gene. The differences in the semi-nested PCR fragments of the polymerase genes among genotypes A through F were greater than 4%, which is consistent with the intergenotypic divergence of at least 4% in HBV DNA S gene sequences. Genotyping using the semi-nested PCR products of the DNA polymerase genes revealed that only genotypes B, C, and D were present in the 50 cases, from Shenyang, China, with a distribution of 11 cases (22%), 25 cases (50%), and 14 cases (28%) respectively. These results demonstrate that our new genotyping method utilizing a fragment of the HBV DNA polymerase gene is valid and can be employed as a general genotyping strategy in areas with prevalent HBV genotypes A through F. In Shenyang, China, genotypes C, B, and D were identified with this new genotyping method, and genotype C was demonstrated to be the dominant genotype

Mechanisms of c-Myc Degradation by Nickel Compounds and Hypoxia

Nickel (Ni) compounds have been found to cause cancer in humans and animal models and to transform cells in culture. At least part of this effect is mediated by stabilization of hypoxia inducible factor (HIF1a) and activating its downstream signaling. Recent studies reported that hypoxia signaling might either antagonize or enhance c-myc activity depending on cell context. We investigated the effect of nickel on c-myc levels, and demonstrated that nickel, hypoxia, and other hypoxia mimetics degraded c-myc protein in a number of cancer cells (A549, MCF-7, MDA-453, and BT-474). The degradation of the c-Myc protein was mediated by the 26S proteosome. Interestingly, knockdown of both HIF-1α and HIF-2α attenuated c-Myc degradation induced by Nickel and hypoxia, suggesting the functional HIF-1α and HIF-2α was required for c-myc degradation. Further studies revealed two potential pathways mediated nickel and hypoxia induced c-myc degradation. Phosphorylation of c-myc at T58 was significantly increased in cells exposed to nickel or hypoxia, leading to increased ubiquitination through Fbw7 ubiquitin ligase. In addition, nickel and hypoxia exposure decreased USP28, a c-myc de-ubiquitinating enzyme, contributing to a higher steady state level of c-myc ubiquitination and promoting c-myc degradation. Furthermore, the reduction of USP28 protein by hypoxia signaling is due to both protein degradation and transcriptional repression. Nickel and hypoxia exposure significantly increased the levels of dimethylated H3 lysine 9 at the USP28 promoter and repressed its expression. Our study demonstrated that Nickel and hypoxia exposure increased c-myc T58 phosphorylation and decreased USP28 protein levels in cancer cells, which both lead to enhanced c-myc ubiquitination and proteasomal degradation