Downregulation of PCK2 remodels tricarboxylic acid cycle in tumor-repopulating cells of melanoma

For cancer cells to proliferate, a balance must be built between biomass-forming, glucose-metabolized intermediates and ATP production. How intrinsic glucose carbon flow regulates this balance remains unclear. Here we show that mitochondrial phosphoenolpyruvate carboxykinase (PCK2), the hub molecule linking tricarboxylic acid (TCA) cycle, glycolysis and gluconeogenesis by conversion of mitochondrial oxaloacetate (OAA) to phosphoenolpyruvate, regulates glucose carbon flow direction in stem-like cells that repopulate tumors (tumor-repopulating cells (TRCs)). PCK2 downregulation accelerated biosynthesis and transportation of citrate from mitochondria to the cytosol, leading to cytosolic glucose carbon flow via OAA-malate-pyruvate and acetyl-CoA-fatty acid pathways in TRCs. On the other hand, downregulating PCK2 hindered fumarate carbon flows in TCA cycle, leading to attenuated oxidative phosphorylation. In pathological terms, PCK2 overexpression slowed TRC growth in vitro and impeded tumorigenesis in vivo. Overall, our work unveiled unexpected glucose carbon flows of TRCs in melanoma that have implications for targeting metabolic aspects of melanoma.

Reconstruction with 3D-printed pelvic endoprostheses after resection of a pelvic tumour

Aims

The aims of this retrospective study were to report the feasibility of using 3D-printing technology for patients with a pelvic tumour who underwent reconstruction.

Patients and Methods

A total of 35 patients underwent resection of a pelvic tumour and reconstruction using 3D-printed endoprostheses between September 2013 and December 2015. According to Enneking’s classification of bone defects, there were three Type I lesions, 12 Type II+III lesions, five Type I+II lesions, two Type I+II+III lesions, ten type I+II+IV lesions and three type I+II+III+IV lesions. A total of three patients underwent reconstruction using an iliac prosthesis, 12 using a standard hemipelvic prosthesis and 20 using a screw-rod connected hemipelvic prosthesis.

Results

All patients had an en bloc resection. Margins were wide in 15 patients, marginal in 14 and intralesional in six. After a mean follow-up of 20.5 months (6 to 30), 25 patients survived without evidence of disease, five were alive with disease and five had died from metastatic disease. Complications included seven patients with delayed wound healing and two with a dislocation of the hip. None had a deep infection. For the 30 surviving patients, the mean Musculoskeletal Society 93 score was 22.7 (20 to 25) for patients with an iliac prosthesis, 19.8 (15 to 26) for those with a standard prosthesis, and 17.7 (9 to 25) for those with a screw-rod connected prosthesis.

Conclusion

The application of 3D-printing technology can facilitate the precise matching and osseointegration between implants and the host bone. We found that the use of 3D-printed pelvic prostheses for reconstruction of the bony defect after resection of a pelvic tumour was safe, without additional complications, and gave good short-term functional results. Cite this article: Bone Joint J 2017;99-B:267–75.

Are beta-blockers effective for preventing post-coronary artery bypass grafting atrial fibrillation? Direct and network meta-analyses

BACKGROUND

Atrial fibrillation is the most common arrhythmia in clinical practice and is a major contributor to mortality. Recently, several studies have reported different results for treatments aimed at reducing the risk of postoperative AF.

AIMS

The aim of this study was to evaluate the efficacy of beta-blockers (BBs) in preventing post-coronary artery bypass grafting (CABG) AF and to compare the efficacies of different BB treatments using a network meta-analytical approach.

METHODS

The PubMed, EMBASE and Cochrane Library databases were searched (Jan 1995 to May 2014) to identify randomized controlled trials. Two independent investigators separately extracted the data using a seven-point scoring system to assess randomization, allocation concealment, blinding, withdrawals and dropouts. A direct meta-analysis of these randomized controlled trials was conducted. Then, six trials comparing different BB treatments for the prevention of postoperative AF were added to perform a Bayesian network meta-analysis with mixed treatment comparisons.

RESULTS

Treatment with BBs was associated with a significant reduction in the postoperative incidence of AF compared with placebo/control [22.37 % compared with 34.45 %, relative risk (RR) = 0.53, 95 % confidence interval (CI): 0.37-0.75, p < 0.00001].

CONCLUSIONS

The network meta-analysis revealed no significant differences among eight types of BB treatments but did provide a ranking. BB treatments could significantly reduce the occurrence of post-CABG AF. Insufficient evidence was available to show that one BB treatment was more effective than the others were. According to our network meta-analysis, bisoprolol and landiolol+bisoprolol are better alternatives compared with the other treatments.

Ultrathin nickel sulfide nano-flames as an electrode for high performance supercapacitor; comparison of symmetric FSS-SCs and electrochemical SCs device

(a) The schematic for fabrication of the symmetric FSS-SCs device, (b) demonstration of FSS-SCs device with the glow of a red LED and (c) the performance comparison of symmetric FSS-SCs and electrochemical SCs device.

Comparative proteomic analysis reveals mite (Varroa destructor) resistance-related proteins in Eastern honeybees (Apis cerana)

The mite (Varroa destructor) has become the greatest threat to apiculture worldwide. As the original host of the mite, Apis cerana can effectively resist the mite. An increased understanding of the resistance mechanisms of Eastern honeybees against V. destructor may help researchers to protect other species against these parasites. In this study, the proteomes of 4 Apis cerana colonies were analyzed using an isobaric tag for relative and absolute quantitation technology. We determined the differences in gene and protein expression between susceptible and resistant colonies that were either unchallenged or challenged by V. destructor. The results showed that a total of 1532 proteins were identified. Gene Ontology enrichment analysis suggested that the transcription factors and basic metabolic and respiratory processes were efficient and feasible factors controlling this resistance, and 12 differentially expressed proteins were identified in Venn analysis. The results were validated by quantitative polymerase chain reaction. This study may provide insight into the genetic mechanisms underlying the resistance of honeybee to mites.

Cytoplasmic p21 is responsible for paclitaxel resistance in ovarian cancer A2780 cells

PURPOSE

P21 which bound to cyclin-dependent kinase complexes was originally described as a suppressor of cancer cell prolifera- tion, while many recent studies have shown p21, when accumulated in the cell cytoplasm, could promote tumor progression. This study was conducted to investigate the role of p21 in the paclitaxel (PTX) resistance of ovarian cancer.

MATERIALS AND METHODS

Regulation of cytoplasmic p21 was performed through transfection of Akt2 constitutively active vector, Akt2 shRNA and p21 siRNA in the ovar- ian cancer cell line A2780. Akt2, p-Akt, and p21 expression were examined by Western blot and cell apoptosis rates were assessed by flow cytometry after treatment with PTX.

RESULTS

Induction of p21 translocation into the cytoplasm via constitutively active Akt2 transfection in A2780 enhanced the resistance to PTX, while inhibition of p21 translocation into the cytoplasm via Akt2 shRNA trans- fection in A2780 cells significantly increased PTX treatment sensitivity. Furthermore, knockdown of cytoplasmic p21 by direct p21 siRNA transfection in Akt2 overexpressed A2780 cells notably increased PTX-induced apoptosis.

CONCLUSION

Cytoplasmic p21 may represent a potential therapeutic target for ovarian tumors that are resistant to PTX treatment.

High-throughput sequencing identification of genes involved with Varroa destructor resistance in the eastern honeybee, Apis cerana

Varroa destructor is the greatest threat to the honeybee Apis mellifera worldwide, while it rarely causes serious harm to its native host, the Eastern honeybee Apis cerana. The genetic mechanisms underlying the resistance of A. cerana to Varroa remain unclear. Thus, understanding the molecular mechanism of resistance to Varroa may provide useful insights for reducing this disease in other organisms. In this study, the transcriptomes of two A. cerana colonies were sequenced using the Illumina Solexa sequencing method. One colony was highly affected by mites, whereas the other colony displayed strong resistance to V. destructor. We determined differences in gene expression in the two colonies after challenging the colonies with V. destructor. After de novo transcriptome assembly, we obtained 91,172 unigenes for A. cerana and found that 288 differentially expressed genes varied by more than 15-fold. A total of 277 unigenes were present at higher levels in the non-affected colony. Genes involved in resistance to Varroa included unigenes related to skeletal muscle movement, olfactory sensitivity, and transcription factors. This suggests that hygienic behavior and grooming behavior may play important roles in the resistance to Varroa.

Five-year follow-up of a prospective study comparing laparoscopic Nissen fundoplication with Stretta radiofrequency for gastroesophageal reflux disease

AIM

Laparoscopic Nissen fundoplication (LNF) and Stretta radiofrequency (RF) are used as main alternative strategies to manage medication-refractory GERD. This study was therefore prospectively evaluated outcomes of patients with refractory GERD 5 years after LNF or Stretta RF.

METHODS

A total of 215 consecutive patients with refractory GERD underwent LNF (N.=102) and Stretta RF (N.=113) in our department between 2007 and 2008. They were followed-up for 5 years, during which the outcome measures including symptom scores of regurgitation, heartburn, chest pain, belching, hiccup, cough and asthma as well as the proton pump inhibitor (PPI) use and complications.

RESULTS

Of the 215 patients, 179 patients following LNF (N.=87) or Stretta RF (N.=92) completed the designated 5-year follow-up and were included in the final analysis. At the end of 5-year follow-up, the post-treatment scores were statistically lower as compared with the pre-treatment scores in both groups, while the symptom improvements after Stretta were significantly lower than that after LNF (p < 0.05). Besides, 81 (91%) patients achieved complete PPI therapy independence after LNF, comparing with 47 (51.1%) after Stretta RF (P<0.05). No significant differences in post-treatment complications were observed except for the abdominal distention.

CONCLUSION

Even though laparoscopic Nissen fundoplication and Stretta RF are capable of controlling GERD symptoms effectively and safely in selected patients, LNF could improve more in symptoms and PPI elimination.

Predicting the target genes of microRNA based on microarray data

MicroRNAs (miRNAs) are small non-coding RNAs of approximately 22 nucleotides in length, which play important roles in regulating gene expression post-transcriptionally. Several computational methods and algorithms have been developed to predict miRNA targets. In this study, we described a method that can be used to integrate miRNA target prediction data from multiple sources and gene expression data to predict target genes of particular miRNAs. We used hsa-miR-375 as an example to test the feasibility of our method. A total of 5645 target genes of hsa-miR-375 were identified from five prediction programs, and among them, 2440 target genes were shared by at least 2 of these 5 programs. By using our method, the number was further reduced to 149 and 5 of the 149 target genes had been validated by previous study. This is a simple yet highly effective approach.

Genetic diversity of the honeybee Apis cerana in Yunnan, China, based on mitochondrial DNA

DNA sequence diversity in the tRNA(leu)-COII portion of the mitochondrial genome was investigated in samples of Apis cerana from Yunnan, China. A fragment of about 480 bp in tRNA(leu)-COII, including a noncoding area and part of COII, was sequenced. The noncoding area was 97-98 bp; 8 haplotypes were found, among which 5 had been reported previously, while 3 were new. The mean diversity of haplotypes was 0.752 ± 0.030 (0.378-0.698), and nucleotide diversity was 0.01073 ± 0.00087 (0.00412-0.01123). A neighbor-joining tree was constructed based on 73 sequences of noncoding intergenic regions in the mtDNA of A. cerana from China and other Asian countries; all haplotypes found in China fell into the mainland Asian group. This result does not support the hypothesis that A. cerana indica occurs in southern Yunnan, which was concluded in a recent report based on morphological variation.