Temozolomide (TMZ) is an oral alkylating agent used to treat glioblastoma multiforme (GBM) and astrocytomas. However, at least 50% of TMZ treated patients do not respond to TMZ. This is due primarily ...to the over-expression of O6-methylguanine methyltransferase (MGMT) and/or lack of a DNA repair pathway in GBM cells. Multiple GBM cell lines are known to contain TMZ resistant cells and several acquired TMZ resistant GBM cell lines have been developed for use in experiments designed to define the mechanism of TMZ resistance and the testing of potential therapeutics. However, the characteristics of intrinsic and adaptive TMZ resistant GBM cells have not been systemically compared. This article reviews the characteristics and mechanisms of TMZ resistance in natural and adapted TMZ resistant GBM cell lines. It also summarizes potential treatment options for TMZ resistant GBMs.
Characterization of the prostate cancer transcriptome and genome has identified chromosomal rearrangements and copy number gains and losses, including ETS gene family fusions, PTEN loss and androgen ...receptor (AR) amplification, which drive prostate cancer development and progression to lethal, metastatic castration-resistant prostate cancer (CRPC). However, less is known about the role of mutations. Here we sequenced the exomes of 50 lethal, heavily pre-treated metastatic CRPCs obtained at rapid autopsy (including three different foci from the same patient) and 11 treatment-naive, high-grade localized prostate cancers. We identified low overall mutation rates even in heavily treated CRPCs (2.00 per megabase) and confirmed the monoclonal origin of lethal CRPC. Integrating exome copy number analysis identified disruptions of CHD1 that define a subtype of ETS gene family fusion-negative prostate cancer. Similarly, we demonstrate that ETS2, which is deleted in approximately one-third of CRPCs (commonly through TMPRSS2:ERG fusions), is also deregulated through mutation. Furthermore, we identified recurrent mutations in multiple chromatin- and histone-modifying genes, including MLL2 (mutated in 8.6% of prostate cancers), and demonstrate interaction of the MLL complex with the AR, which is required for AR-mediated signalling. We also identified novel recurrent mutations in the AR collaborating factor FOXA1, which is mutated in 5 of 147 (3.4%) prostate cancers (both untreated localized prostate cancer and CRPC), and showed that mutated FOXA1 represses androgen signalling and increases tumour growth. Proteins that physically interact with the AR, such as the ERG gene fusion product, FOXA1, MLL2, UTX (also known as KDM6A) and ASXL1 were found to be mutated in CRPC. In summary, we describe the mutational landscape of a heavily treated metastatic cancer, identify novel mechanisms of AR signalling deregulated in prostate cancer, and prioritize candidates for future study.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
The oligosaccharyltransferase (OT) complex catalyzes N‐glycosylation of nascent secretory polypeptides in the lumen of the endoplasmic reticulum. Despite their importance, little is known ...about the structure and function of plant OT complexes, mainly due to lack of efficient recombinant protein production systems suitable for studies on large plant protein complexes. Here, we purified Arabidopsis OT complexes using the tandem affinity‐tagged OT subunit STAUROSPORINE AND TEMPERATURE SENSITIVE3a (STT3a) expressed by an Arabidopsis protein super‐expression platform. Mass‐spectrometry analysis of the purified complexes identified three essential OT subunits, OLIGOSACCHARYLTRANSFERASE1 (OST1), HAPLESS6 (HAP6), DEFECTIVE GLYCOSYLATION1 (DGL1), and a number of ribosomal subunits. Transmission‐electron microscopy showed that STT3a becomes incorporated into OT–ribosome super‐complexes formed in vivo, demonstrating that this expression/purification platform is suitable for analysis of large protein complexes. Pairwise in planta interaction analyses of individual OT subunits demonstrated that all subunits identified in animal OT complexes are conserved in Arabidopsis and physically interact with STT3a. Genetic analysis of newly established OT subunit mutants for OST1 and DEFENDER AGAINST APOTOTIC DEATH (DAD) family genes revealed that OST1 and DAD1/2 subunits are essential for the plant life cycle. However, mutations in these individual isoforms produced much milder growth/underglycosylation phenotypes than previously reported for mutations in DGL1, OST3/6 and STT3a.
Significance Statement
A protein super‐expression system was established that is suitable for studying higher‐order structure and function of protein super‐complexes using Arabidopsis cell cultures. The system enabled the production and isolation of authentic oligosaccharyltransferase (OT) complexes assembled on a recombinant STT3a subunit, leading to identification and characterization of OT subunits and solving the three‐dimensional structure of plant OT–ribosome complexes.
The coronavirus disease 2019 (COVID‐19) pandemic has casted a huge impact on global public health and the economy. In this challenging situation, older people are vulnerable to the infection and the ...secondary effects of the pandemic and need special attention. To evaluate the impacts of COVID‐19 on older people, it is important to balance the successful pandemic control and active management of secondary consequences. These considerations are particularly salient in the Asian context, with its diversity among countries in terms of sociocultural heritage, healthcare setup and availability of resources. Thus, the Asian Working Group for Sarcopenia summarized the considerations of Asian countries focusing on responses and difficulties in each country, impacts of health inequity related to the COVID‐19 pandemic and proposed recommendations for older people, which are germane to the Asian context. More innovative services should be developed to address the increasing demands for new approaches to deliver healthcare in these difficult times and to establish resilient healthcare systems for older people. Geriatr Gerontol Int 2020; 9999: n/a–n/a.
Studies suggest that Schisandra chinensis Baillon (Sc) may enhance muscle strength and mass because of its anti-inflammatory and antioxidant properties.
We aimed to examine the effects and safety of ...consumption of Sc extract (SCe) for 12 wk on muscle strength and mass in older adults with relatively low muscle mass who do low-intensity exercise.
A randomized, double-blind, placebo-controlled trial was performed in adults >50 y of age. Fifty-four participants were randomly assigned into 2 groups and, for 12 wk, received either 1 g SCe/d or a placebo. All participants were required to walk for 30–60 min/d for >3 d/wk during the trial period. At baseline and at 4 and 12 wk after treatment, the participants were examined for knee extension strength using Biodex isokinetic dynamometers, handgrip strengths, and body composition, and blood tests were performed. The Euro-QoL-5D (EQ-5D) questionnaire and the FFQ were administered at baseline and at 12 wk after treatment. Physical activity was assessed using a self-recorded daily exercise log and an accelerometer during the study.
SCe supplementation over 12 wk caused a higher increase in right knee extensor strength by 10.2 Nm (95% CI: 3.7, 16.8 Nm; P = 0.003) and left knee extensor strength by 6.7 Nm (95% CI: 0.3, 13.1 Nm; P = 0.041) than did the placebo. However, no differences were observed in the muscle mass, anti-inflammatory markers, antioxidative markers, and EQ-5D score between the groups. None of the participants experienced adverse events.
SCe supplementation may enhance skeletal muscle strength but not mass in older adults who perform low-intensity exercise. This trial was registered at clinicaltrials.gov as NCT03402308.
Plastics, used everyday, are mostly synthetic polymers derived from fossil resources, and their accumulation is becoming a serious concern worldwide. Polyhydroxyalkanoates (PHAs) are naturally ...produced polyesters synthesized and intracellularly accumulated by many different microorganisms. PHAs are good alternatives to petroleum‐based plastics because they possess a wide range of material properties depending on monomer types and molecular weights. In addition, PHAs are biodegradable and can be produced from renewable biomass. Thus, producing PHAs through the development of high‐performance engineered microorganisms and efficient bioprocesses gained much interest. In addition, non‐natural polyesters comprising 2‐hydroxycarboxylic acids as monomers have been produced by fermentation of metabolically engineered bacteria. For example, poly(lactic acid) and poly(lactic acid‐co‐glycolic acid), which have been chemically synthesized using the corresponding monomers either fermentatively or chemically produced, can be produced by metabolically engineered bacteria by one‐step fermentation. Recently, PHAs containing aromatic monomers could be produced by fermentation of metabolically engineered bacteria. Here, metabolic engineering strategies applied in developing microbial strains capable of producing non‐natural polyesters in a stepwise manner are reviewed. It is hoped that the detailed strategies described will be helpful for designing metabolic engineering strategies for developing diverse microbial strains capable of producing various polymers that can replace petroleum‐derived polymers.
Systems metabolic engineering strategies applied for the biosynthesis of non‐natural polyesters such as poly(lactic acid) (PLA), poly(lactic acid‐co‐glycolic acid) (PLGA), and poly(3‐hydroxybutyrate‐co‐d‐phenyllactate) are described. These strategies include protein engineering, metabolic engineering, synthetic biology, systems biology, and bioprocess engineering. Sequential and iterative application of these strategies allows one‐step direct fermentative production of several non‐natural polyesters directly from the renewable resources.
Lymphatic remodeling in inflammation has been found in tracheal mycoplasma infection, human kidney transplant, skin inflammation, peritonitis, and corneal inflammation. Here we investigated ...lymphangiogenesis in fibrotic area in unilateral ureteral obstruction, a model of progressive renal fibrosis, and evaluated the roles of vascular endothelial growth factor (VEGF)-C and -D in the obstructed kidney. Compared to sham-operated mice, the number of LYVE-1-positive lymphatic vessels, the proliferation of LYVE-1-positive lymphatic endothelial cells, along with VEGF-C and -D mRNA expression were all significantly increased following ureteral obstruction. Depletion of macrophages with clodronate decreased lymphangiogenesis in the obstructed kidney. VEGF-C expression was higher in M2- than in M1-polarized macrophages from bone marrow–derived macrophages, and also increased in Raw 264.7 or renal proximal tubule cells by stimulation with TGF-β1 or TNF-α. VEGF-D reversed the inhibitory effect of TGF-β1 on VEGF-C-induced migration, capillary-like tube formation, and proliferation of human lymphatic endothelial cells. Additionally, the blockade of VEGF-C and VEGF-D signaling decreased obstruction-induced lymphangiogenesis. Thus, VEGF-C and VEGF-D are associated with lymphangiogenesis in the fibrotic kidney in a mouse model of ureteral obstruction.
The establishment of better selection criteria for identifying sub-populations that may benefit from treatment is a key aspect of the development and success of targeted therapy. To investigate ...methods for assessing MET overexpression in gastric cancer, we conducted immunohistochemistry using a new anti-Total MET monoclonal antibody in a single-institution cohort of 495 patients. As antibody is directed against a membranous and/or cytoplasmic epitope, two interpretation methods were used: (1) membranous and cytoplasmic and (2) membranous alone. In selected 120 cases, copy number gain and mRNA expression levels were measured using quantitative real-time PCR. Further in situ hybridization confirmed the presence of MET gene amplification. Among the 495 gastric cancers, simultaneous membranous and cytoplasmic overexpression of MET was found in 108 cases (21.8%) and membranous alone overexpression was observed in 40 cases (8.1%). The highest correlation was observed in membranous and cytoplasmic staining of MET: MET expression scores correlated significantly with high MET mRNA levels (r=0.465, P<0.0001), increased copy number gain (r=0.393, P=0.000002) and amplification of MET gene. Moreover, patients with MET overexpression showed shorter overall survival (HR, 1.781; 95% CI, 1.324-2.395; P<0.001) and disease-free survival (HR, 1.765; 95% CI, 1.227-2.541; P=0.002) compared with patients without MET overexpression. However, membranous overexpression of MET did not highly correlate with mRNA level (r=0.274, P=0.002), copy number gain or survival (P>0.05). We developed highly correlating interpretation methods of MET immunohistochemistry in gastric carcinomas. MET overexpression is an independent prognostic factor and could be a potential target and predictor of benefit for targeted therapy with MET inhibitors.
This study aimed to determine how the muscle mass of the lower leg affects the preservation of the lower extremities in patients with diabetic foot ulcer. This study analyzed patients with diabetic ...foot ulcer between January 2014 and June 2018 with a follow-up of at least 2 years. Of these 181 patients whose ulcer is located distal to the metatarsophalangeal joint, which was categorized as grade ≤2 by the Wagner classification were classified into 4 grades: grade 0 (treated without amputation), grade 1 (amputation distal to the metatarsophalangeal joint), grade 2 (Ray, transmetatarsal, Lisfranc, and Chopart amputation), and grade 3 (Syme, below-knee, and above-knee amputation) according to the final amputation degree. The muscles of the lower leg were classified into 4 compartments: anterior, lateral, deep posterior, and superficial posterior. The cross-sectional area and attenuation to estimate the muscle volume and density were measured at the axial image of computed tomography (CT) angiography. No significant differences were observed in the sex ratio and mean age among the grades (P = .966 and .962). The cross-sectional area of the anterior, lateral, and posterior compartments demonstrated no significant differences, but that of the superficial posterior compartment exhibited significant differences among the grades (P < .001). Moreover, the attenuation of the anterior, lateral, and deep posterior compartments showed no significant differences, but that of the posterior compartment showed significant differences among the grades (P = .003). The muscle mass of the superficial posterior compartment of the lower leg could be a good indicator of the preservation of the lower extremity in patients with diabetic foot ulcer. Therefore, a strengthening exercise for the triceps surae and plantaris muscles in the early stage could help preserve as much of the lower extremities as possible.
The homeostatic iron regulator protein HFE is involved in regulation of iron acquisition for cells. The prevalence of two common HFE gene variants (H63D, C282Y) has been studied in many cancer types; ...however, the impact of HFE variants, sex and HFE gene expression in lung cancer has not been studied. We determined the prevalence of HFE variants and their impact on cancer phenotypes in lung cancer cell lines, in lung cancer patient specimens, and using The Cancer Genome Atlas (TCGA) database. We found that seven out of ten human lung cancer cell lines carry the H63D or C282Y HFE variant. Analysis of lung cancer specimens from our institute (Penn State Hershey Medical Center) revealed a sex and genotype interaction risk for metastasis in lung adenocarcinoma (LUAD) patients; H63D HFE is associated with less metastasis in males compared to wild type (WT) HFE; however, females with the H63D HFE variant tend to develop more metastatic tumors than WT female patients. In the TCGA LUAD dataset, the H63D HFE variant was associated with poorer survival in females compared to females with WT HFE. The frequency of C282Y HFE is higher in female lung squamous cell carcinoma (LUSC) patients of TCGA than males, however the C282Y HFE variant did not impact the survival of LUSC patients. In the TCGA LUSC dataset, C282Y HFE patients (especially females) had poorer survival than WT HFE patients. HFE expression level was not affected by HFE genotype status and did not impact patient's survival, regardless of sex. In summary, these data suggest that there is a sexually dimorphic effect of HFE polymorphisms in the survival and metastatic disease in lung cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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