The defect nature of photoluminescence from a porous silicon nanowire array

The orange luminescence in porous Si nanowires prepared by metal-assisted etching is of defect nature and can be assigned to donor–acceptor pair (DAP)-like recombination.

Multifunctional polyamidoamine-modified selenium nanoparticles dual-delivering siRNA and cisplatin to A549/DDP cells for reversal multidrug resistance

Multidrug resistance (MDR) is a major barrier against effective cancer treatment. Dual-delivering a therapeutic small interfering RNA (siRNA) and chemotherapeutic agents has been developed to reverse drug resistance in tumor cells. In this study, amine-terminated generation 5 polyamidoamine (PAMAM) dendrimers (G5.NH2)-modified selenium nanoparticles (G5@Se NP) were synthesized for the systemic dual-delivery of mdr1 siRNA and cisplatin (cis-diamminedichloroplatinum-(II), DDP), which was demonstrated to enhance siRNA loading, releasing efficiency and gene-silencing efficacy. When the mdr1 siRNA was conjugated with G5@Se NP via electrostatic interaction, a significant down-regulation of P-glycoprotein and multidrug resistance-associated protein expression was observed; G5@Se-DDP-siRNA arrested A549/DDP cells at G1 phase and led to enhanced cytotoxicity in A549/DDP cells through induction of apoptosis involving the AKT and ERK signaling pathways. Interestingly, G5@Se-DDP NP were much less reactive than DDP in the reactions with both MT and GSH, indicating that loading of DDP in a nano-delivery system could effectively prevent cell detoxification. Furthermore, animal studies demonstrated that the new delivery system of G5@Se-DDP-siRNA significantly enhanced the anti-tumor effect on tumor-bearing nude mice, with no appreciable abnormality in the major organs. These results suggest that G5@Se NP could be a potential platform to combine chemotherapy and gene therapy technology in the treatment of human disease.

The abnormal expression level of microRNA in epithelial-mesenchymal transition of peritoneal mesothelial cells induced by high glucose

OBJECTIVE

To determine the expression level of the microRNA in the process of epithelial-mesenchymal transition (EMT) of the peritoneal mesothelial cells (PMCs) induced by high glucose.

MATERIALS AND METHODS

The PMCs were cultured using M199 medium with 10% fetal bovine serum, and the EMT was induced by D-glucose stimulation. Epithelial-mesenchymal transition was determined by changes in cell morphology and the expression levels of the EMT marker genes. Changes in cell morphology were observed by inverted microscope, and the expression levels of the EMT marker genes were determined by real-time PCR. The expression levels of the microRNA were detected by real-time PCR with microRNA-specific stem-loop structure primer.

RESULTS

The PMCs changed to fusiformis following a high-glucose medium stimulated for 48 hours, and the EMT marker genes changed significantly, such as the decrease of E-cadherin and an increase of Vimentin (p < 0.01). These results proved the EMT had been induced by high-glucose. Applying real-time PCR with microRNA-specific stem-loop structure primer, miR-193a increased notably (p < 0.01), and miR-15a and let-7e decreased (p < 0.01), while miR-16 and miR-21 had no significant changes (p > 0.05). Most importantly, the increase of miR-193a was correlated with stimulus duration.

CONCLUSIONS

MicroRNA with abnormal expression levels have a primary role in regulating the EMT of PMCs induced by high glucose.

ERK and p38MAPK pathways regulate myosin light chain phosphatase and contribute to Ca2+ sensitization of intestinal smooth muscle contraction

BACKGROUND

Mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated protein kinase (ERK) and p38MAPK, are known regulators of smooth muscle contractility. The contraction of smooth muscle is mainly regulated by the phosphorylation of regulatory light chains of myosin II (LC20), which is driven by the balance between myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP). We hypothesized that one possible mechanism for MAPK-dependent modulation of intestinal smooth muscle contractility is via the regulation of MLCP activity.

METHODS

Contractile responses to carbachol (CCh) and effects of MAPK inhibitors on CCh-induced contractions were assessed with isolated rat ileal longitudinal smooth muscle strips. Biochemical assessments of MLCP activity and myosin phosphatse targeting subunit (MYPT1) and CPI-17 phosphorylations were completed.

KEY RESULTS

Treatment of ileal smooth muscle with PD98059 (10 μM; MEK inhibitor) or SB203580 (10 μM; p38MAPK inhibitor) significantly inhibited CCh-induced contractile force. Decreased MLCP activity was observed during sustained contractions induced by CCh; the MLCP activity was recovered by treatment with PD98059 and SB203580. However, MYPT1 (Thr697 and Thr855) and CPI-17 (Thr38) phosphorylations were not affected. Application of ML-7 (MLCK inhibitor) during CCh-induced sustained contraction elicited an MLCP-dependent relaxation, the rate of which was accelerated by application of PD98059 and SB203580 with proportional changes in LC20 phosphorylation levels but not MYPT1 phosphorylation (Thr697 or Thr855).

CONCLUSIONS & INFERENCES

ERK and p38MAPK contribute to CCh-induced sustained contraction in a LC20 phosphorylation dependent manner. Moreover, both kinases inhibit MLCP activity possibly by a novel mechanism.

Clinical study on gastric cancer susceptibility genes IL-10-1082 and TNF-α

TNF 308 gene polymorphism and IL-10 polymorphism provided evidence in diagnosing some types of cancer. We aimed to explore the relation of gene polymorphism with gastric cancer. A total of 360 cases of gastric cancer patients were included in the study. The genotypes GG, GA, and AA of the interleukin-10-1082 gene (IL-10-1082) and the tumor necrosis factor-alpha gene (TNF-α) 308 polymorphism were examined by chromogenic detection. Three hundred healthy individuals' gene as control group were also examined. The GA 308 genotype of TNF-α differed significantly between the control group and the gastric cancer group (X(2) = 9.32, P < 0.05). Genotype frequencies of A/A (17.2%), A/G (26.2%), and G/G (9.1%) of the IL-10-1082 gene polymorphism in the gastric cancer group differed significantly compared to those of the control group (X(2) = 20.32, P < 0.05). The IL-10-1082 gene and the GA 308 genotype of the TNF-α gene were found to be susceptibility genes for gastric cancer.

BST-2 expression in human hepatocytes is inducible by all three types of interferons and restricts production of hepatitis C virus

Bone marrow stromal cell antigen 2 (BST-2, also known as tetherin, CD317, or HM1.24) has recently been identified as a host restriction factor against diverse families of enveloped viruses. However, the effects of BST-2 on the life cycle of hepatitis C virus (HCV), an enveloped RNA virus, remain unclear and controversial. Here we demonstrated that human hepatocytes including Huh7.5.1 cells, primary human hepatocytes (PHHs), and HepG2 cells constitutively expressed low to moderate levels of endogenous BST-2 on the cell surface, which could be robustly up-regulated by all three types of interferons (IFNs) such as IFN-α, IFN-γ, and IFN-λ. IFN-α and IFN-γ showed a synergistic effect in induction of BST-2 expression on human hepatocytes. Over-expression of BST-2 by BST-2-expressing vector transfection or up-regulation of BST-2 by IFN stimulation markedly suppressed HCV production, whereas shRNA-mediated depletion of endogenous BST-2 significantly enhanced HCV production in infected Huh7.5.1 cells. IFN-mediated anti-HCV activity was partially but significantly diminished by shRNA-mediated knockdown of BST-2 expression, indicating that BST- 2 upregulation is directly involved in IFN-mediated inhibition of HCV production. We also found that both BST-2 and HCV core co-localized with intracellular lipid droplets (LDs), suggesting that BST-2-HCV interaction may take place around LDs as LDs constitute an important intracellular organelle for HCV assembly and replication. Taken together, our data suggest that BST-2 is a host restriction factor against HCV, and induction of BST-2 in hepatocytes could be one of the mechanisms by which current HCV standard therapy (IFN-α plus ribavirin) achieves a sustained virological response (SVR).

ABCB1 polymorphisms predict imatinib response in chronic myeloid leukemia patients: a systematic review and meta-analysis

Imatinib mesylate, a competitive tyrosine kinase inhibitor, is considered the first-line therapy drug for Ph+ chronic myeloid leukemia (CML). Three single-nucleotide polymorphisms (SNPs) in the ATP-binding cassette, subfamily B (MDR/TAP), member 1 gene (ABCB1/MDR1), c.1236C>T, c.2677G>T/A and c.3435C>T, have been shown to affect cellular transport/metabolism of imatinib. The associations between these SNPs and imatinib response in CML patients have been widely evaluated, but the results were inconsistent. To derive a conclusive assessment of the associations, we performed a meta-analysis by combining data from a total of 12 reports including 1826 patients. The results showed that the 2677G allele or 3435T allele predicted a worse response to imatinib in CML patients, whereas 1236CC genotype was associated with better response in CML patients from Asian region. In conclusion, this meta-analysis suggests that c.1236C>T, c.2677G>T/A and c.3435C>T can be served as predictive markers for the therapeutical use of imatinib in CML patients.

Parathyroid hormone-related peptide (PTHrP): prokaryotic expression, purification, and preparation of a polyclonal antibody

Parathyroid hormone-related peptide (PTHrP) plays important roles in promoting cancer occurrence and in the development of bone metastases. To increase our knowledge of the biological functions of PTHrP, the prokaryotic expression vector pET-PTHrP was successfully constructed and the His-PTHrP fusion protein was expressed in Escherichia coli. Anti-PTHrP polyclonal antibody was then prepared from rabbits. Finally, the goat tissue expression profile of PTHrP was analyzed by Western blot with the anti-PTHrP polyclonal antibody. The results showed that the expression of PTHrP in goat mammary glands was significantly higher than that in other organs. This indicates that PTHrP may play important roles in the goat mammary gland. The antibody prepared will be a useful tool for detecting PTHrP and will be valuable in future studies investigating the role of PTHrP in calcium metabolism in the goat model.

Combined effects of leukocyte telomere length, p53 polymorphism and human papillomavirus infection on esophageal squamous cell carcinoma in a Han Chinese population

Telomere shortening has been suggested to be a genetic predictor for various cancers. However, evidences about this point with respect to esophageal squamous cell carcinoma (ESCC) in Han Chinese populations remain limited. Our previous study demonstrated that p53 Arg72Pro polymorphism was associated with the risk of human papillomavirus (HPV)-related ESCC. Telomeres and p53 play important roles in maintaining genomic stability and regulating the cell cycle. HPV impacts both telomere length stabilization and p53 degradation. Given the roles of the three factors, we evaluated leukocyte telomere length, p53 variants and HPV-16 serology to examine the potential associations between them and ESCC risk in a case-control study with 308 patients and 309 cancer-free controls matched by age and sex. Compared with long telomere length, short telomere length was significantly associated with an increased risk of ESCC (adjusted OR 2.01; 95% CI 1.41-2.80). Moreover, this association was enhanced when combined with HPV-16 seropositivity and p53 Arg/Arg or Arg/Pro genotypes. Notably, individuals with short telomere length, Arg/Pro or Arg/Arg genotypes and HPV-16 seropositivity had a 12.08-fold (95% CI 5.49-26.56) increased risk of ESCC compared to those with none of the three investigated risk factors. Taken together, these results indicate that short telomere length in peripheral blood leukocytes is a biomarker for ESCC risk, and has statistically additive effects with p53 variants and HPV seropositivity with regard to the risk of ESCC in a Han Chinese population.

The Polycomb group (PcG) protein EZH2 supports the survival of PAX3-FOXO1 alveolar rhabdomyosarcoma by repressing FBXO32 (Atrogin1/MAFbx)

The Polycomb group (PcG) proteins regulate stem cell differentiation via the repression of gene transcription, and their deregulation has been widely implicated in cancer development. The PcG protein Enhancer of Zeste Homolog 2 (EZH2) works as a catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) by methylating lysine 27 on histone H3 (H3K27me3), a hallmark of PRC2-mediated gene repression. In skeletal muscle progenitors, EZH2 prevents an unscheduled differentiation by repressing muscle-specific gene expression and is downregulated during the course of differentiation. In rhabdomyosarcoma (RMS), a pediatric soft-tissue sarcoma thought to arise from myogenic precursors, EZH2 is abnormally expressed and its downregulation in vitro leads to muscle-like differentiation of RMS cells of the embryonal variant. However, the role of EZH2 in the clinically aggressive subgroup of alveolar RMS, characterized by the expression of PAX3-FOXO1 oncoprotein, remains unknown. We show here that EZH2 depletion in these cells leads to programmed cell death. Transcriptional derepression of F-box protein 32 (FBXO32) (Atrogin1/MAFbx), a gene associated with muscle homeostasis, was evidenced in PAX3-FOXO1 RMS cells silenced for EZH2. This phenomenon was associated with reduced EZH2 occupancy and H3K27me3 levels at the FBXO32 promoter. Simultaneous knockdown of FBXO32 and EZH2 in PAX3-FOXO1 RMS cells impaired the pro-apoptotic response, whereas the overexpression of FBXO32 facilitated programmed cell death in EZH2-depleted cells. Pharmacological inhibition of EZH2 by either 3-Deazaneplanocin A or a catalytic EZH2 inhibitor mirrored the phenotypic and molecular effects of EZH2 knockdown in vitro and prevented tumor growth in vivo. Collectively, these results indicate that EZH2 is a key factor in the proliferation and survival of PAX3-FOXO1 alveolar RMS cells working, at least in part, by repressing FBXO32. They also suggest that the reducing activity of EZH2 could represent a novel adjuvant strategy to eradicate high-risk PAX3-FOXO1 alveolar RMS.

The use of pH-sensitive functional selenium nanoparticles shows enhanced in vivo VEGF-siRNA silencing and fluorescence imaging

The utility of small interfering RNAs (siRNAs) has shown great promise in treating a variety of diseases including many types of cancer. While their ability to silence a wide range of target genes underlies their effectiveness, the application of therapies remains hindered by a lack of an effective delivery system. In this study, we sought to develop an siRNA-delivery system for VEGF, a known signaling molecule involved in cancer, that consists of two selenium nanoparticles SeNPs and G2/PAH-Cit/SeNPs. A G2/PAH-Cit/SeNP is a pH-sensitive delivery system that is capable of enhancing siRNA loading, thus increasing siRNA release efficiency and subsequent target gene silencing both in vitro and in vivo. In vivo experiments using G2/PAH-Cit/SeNPs@siRNA led to significantly higher accumulation of siRNA within the tumor itself, VEGF gene silencing, and reduced angiogenesis in the tumor. Furthermore, the G2/PAH-Cit/SeNP delivery system not only enhanced anti-tumor effects on tumor-bearing nude mice as compared to SeNPs@siRNA, but also resulted in weak occurrence of lesions in major target organs. In sum, this study provides a new class of siRNA delivery system, thereby providing an alternative therapeutic route for cancer treatment.

Effectiveness and security of CT-guided percutaneous implantation of (125)I seeds in pancreatic carcinoma

OBJECTIVE

To assess the effectiveness and security of CT-guided percutaneous implantation of iodine-125 ((125)I)-labelled seeds in pancreatic carcinoma.

METHODS

A total of 36 patients (25 males and 11 females) with an average age of 57 years (range, 39-84 years) were enrolled and categorized into Stage III (27 cases) and Stage IV (9 cases) of pancreatic cancer. There were 3 tumours in the pancreatic head and 33 tumours in the pancreatic body or tail. The average diameter of the tumours was 37.1 mm (range, 15-65 mm). The implantation of (125)I seeds was performed by using 18-G needles (length, 150-200 mm) through the anterior, lateral and posterior approaches. Then, (125)I seeds were loaded and released into the lesions.

RESULTS

Implantations were performed via the anterior (23 patients), lateral (9 patients) and posterior (4 patients) approaches. During implantation, 3-14 punctures were performed for each patient, and a total of 164 punctures were recorded. Meanwhile, a total of 657 seeds were implanted with an average of 25.27 (range, 12-50) seeds per patient, and the success rate was 100%. The activity of each seed ranged from 0.55 to 0.65 mCi. A main adverse event occurred in one puncture and minor events in seven punctures. No significant relationship between the punctures or adverse events was identified. No serious complication was detected after the implantations during follow-up visits.

CONCLUSION

This study suggested that CT-guided percutaneous implantation of (125)I seeds in a pancreatic carcinoma was relatively safe and effective for treating unresectable pancreatic cancer.

ADVANCES IN KNOWLEDGE

The CT-guided percutaneous implantation of (125)I seeds in unresectable pancreatic cancer showed highly successful rates without serious complications.

Epigallocatechin-3-gallate (EGCG)-stabilized selenium nanoparticles coated with Tet-1 peptide to reduce amyloid-β aggregation and cytotoxicity

Alzheimer's disease (AD), the most common neurodegenerative disease, is caused by an accumulation of amyloid-β (Aβ) plaque deposits in the brains. Evidence is increasingly showing that epigallocatechin-3-gallate (EGCG) can partly protect cells from Aβ-mediated neurotoxicity by inhibiting Aβ aggregation. In order to better understand the process of Aβ aggregation and amyloid fibril disaggregation and reduce the cytotoxicity of EGCG at high doses, we attached EGCG onto the surface of selenium nanoparticles (EGCG@Se). Given the low delivery efficiency of EGCG@Se to the targeted cells and the involvement of selenoprotein in antioxidation and neuroprotection, which are the key factors for preventing the onset and progression of AD, we synthesized EGCG-stabilized selenium nanoparticles coated with Tet-1 peptide (Tet-1-EGCG@Se, a synthetic selenoprotein analogue), considering the affinity of Tet-1 peptide to neurons. We revealed that Tet-1-EGCG@Se can effectively inhibit Aβ fibrillation and disaggregate preformed Aβ fibrils into nontoxic aggregates. In addition, we found that both EGCG@Se and Tet-1-EGCG@Se can label Aβ fibrils with a high affinity, and Tet-1 peptides can significantly enhance the cellular uptake of Tet-1-EGCG@Se in PC12 cells rather than in NIH/3T3 cells.

Clinical significance of PIK3CA and survivin in primary adenosquamous lung carcinoma

The aim of this study was to evaluate the expression of PIK3CA and survivin in adenosquamous lung cancer (ASC) patients and their clinicopathological significance. A total of 32 patients with adenosquamous carcinoma and ten cases of normal lung lesion were investigated, and the expressions of PIK3CA and survivin were detected by immunohistochemistry. The PIK3CA and survivin expression in adenosquamous lung carcinoma tissues was significantly higher than those of the normal lesions (p = 0.02). The positive rate of PIK3CA and survivin expressions was in accordance with the tumor-node-metastasis stage (p = 0.002/0.013), pathological grade (p = 0.019/0.013), and lymph node metastasis (p = 0.029/0.008). Out of 15 patients with definite follow-ups, highly positive expressions of PIK3CA (12 cases) and survivin (11 cases) were suggested to be associated with adverse prognosis (nine cases recurrence and four cases died). A positive correlation was also observed between the expressions of PIK3CA and survivin (r = 0.622, p < 0.001). These findings indicated that PIK3CA and survivin up-regulation might play an important role in lymph node metastasis and adverse prognosis in ASC. Nevertheless, further additional prospective studies in the area of ASC molecular profiling are needed.