Overexpression of metadherin mediates metastasis of osteosarcoma by regulating epithelial-mesenchymal transition

OBJECTIVES

Osteosarcoma (OS) is one of the most common primary malignant bone tumours of childhood and adolescence, and is characterized by high propensity for metastasis (specially to the lung), which is the main cause of death. However, molecular mechanisms underlying metastasis of OS are still poorly understood.

MATERIALS AND METHODS

Metadherin (MTDH) was identified to be significantly upregulated in OS tissues that had metastasized compared to OS without metastasis, using a two-dimensional approach of electrophoresis, coupled with mass spectrometry. To understand the function of MTDH in OS, OS cell lines U2OS and SOSP-M were transfected with retroviral shRNA vector against MTDH.

RESULTS

It was found that metastatic propensity as well as cell proliferation were significantly reduced in both U2OS and SOSP-M. Migration and invasion of U2OS and SOSP-M cells were significantly lower after knock-down of MTDH. In addition, epithelial-mesenchymal transition (EMT) was reduced after knock-down of MTDH. Clinicopathologically, overexpression of MTDH was significantly associated with metastasis and poor survival of patients with OS.

CONCLUSION

Taken together, our results demonstrate that MTDH mediated metastasis of OS through regulating EMT. This could be an ideal therapeutic target against metastasis of OS.

miR-221/222 confers radioresistance in glioblastoma cells through activating Akt independent of PTEN status

Glioblastoma is highly resistant to radiation therapy. The underlying molecular mechanism is not completely understood. The DNA damage response (DDR) pathway plays a crucial role in radioresistance of glioablastoma cells. Growing evidence has demonstrated that radiation induces alterations in microRNA (miR) profiles. However, how radiation induces specific miRs and how they might regulate the DDR remain elusive. In our study, we found that radiation induced c-jun transcription of miR-221 and miR-222. miR-221 and miR- 222 modulated DNA-PKcs expression to affect DNA damage repair by activating Akt independent of PTEN status. Knocking down of miR-221/222 significantly increased radiosensitivity of glioblastoma cells. Inhibition of Akt by RNAi or LY294002 treatment may overcome miR-221/222 induced radioresistance. Notably, combined anti-miR-221/222 and radiotherapy has remarkably inhibited tumor growth compared with anti-miR-221/222 or radiotherapy alone in a subcutaneous mouse model. Our results suggest that radio-induced c-jun promotes transcription of miR-221/222, which mediates DNA damage repair of glioblastoma cells independent of PTEN. These data indicate for the first time that miR-221/222 play an important role in mediating radio-induced DNA damage repair and that miR-221/222 could serve as potential therapeutic targets for increasing radiosensitivity of glioblastoma cells.

E3 ubiquitin ligase TRIM32 negatively regulates tumor suppressor p53 to promote tumorigenesis

Tumor suppressor p53 has a key role in maintaining genomic stability and preventing tumorigenesis through its regulation of cellular stress responses, including apoptosis, cell cycle arrest and senescence. To ensure its proper levels and functions in cells, p53 is tightly regulated mainly through post-translational modifications, such as ubiquitination. Here, we identified E3 ubiquitin ligase TRIM32 as a novel p53 target gene and negative regulator to regulate p53-mediated stress responses. In response to stress, such as DNA damage, p53 binds to the p53 responsive element in the promoter of the TRIM32 gene and transcriptionally induces the expression of TRIM32 in cells. In turn, TRIM32 interacts with p53 and promotes p53 degradation through ubiquitination. Thus, TRIM32 negatively regulates p53-mediated apoptosis, cell cycle arrest and senescence in response to stress. TRIM32 is frequently overexpressed in different types of human tumors. TRIM32 overexpression promotes cell oncogenic transformation and tumorigenesis in mice in a largely p53-dependent manner. Taken together, our results demonstrated that as a novel p53 target and a novel negative regulator for p53, TRIM32 has an important role in regulation of p53 and p53-mediated cellular stress responses. Furthermore, our results also revealed that impairing p53 function is a novel mechanism for TRIM32 in tumorigenesis.

A multifunctional ribonuclease A-conjugated carbon dot cluster nanosystem for synchronous cancer imaging and therapy

Carbon dots exhibit great potential in applications such as molecular imaging and in vivo molecular tracking. However, how to enhance fluorescence intensity of carbon dots has become a great challenge. Herein, we report for the first time a new strategy to synthesize fluorescent carbon dots (C-dots) with high quantum yields by using ribonuclease A (RNase A) as a biomolecular templating agent under microwave irradiation. The synthesized RNase A-conjugated carbon dots (RNase A@C-dots) exhibited quantum yields of 24.20%. The fluorescent color of the RNase A@C-dots can easily be adjusted by varying the microwave reaction time and microwave power. Moreover, the emission wavelength and intensity of RNase A@C-dots displayed a marked excitation wavelength-dependent character. As the excitation wavelength alters from 300 to 500 nm, the photoluminescence (PL) peak exhibits gradually redshifts from 450 to 550 nm, and the intensity reaches its maximum at an excitation wavelength of 380 nm. Its Stokes shift is about 80 nm. Notably, the PL intensity is gradually decreasing as the pH increases, almost linearly dependent, and it reaches the maximum at a pH = 2 condition; the emission peaks also show clearly a redshift, which may be caused by the high activity and perfective dispersion of RNase A in a lower pH solution. In high pH solution, RNase A tends to form RNase A warped carbon dot nanoclusters. Cell imaging confirmed that the RNase A@C-dots could enter into the cytoplasm through cell endocytosis. 3D confocal imaging and transmission electron microscopy observation confirmed partial RNase A@C-dots located inside the nucleus. MTT and real-time cell electronic sensing (RT-CES) analysis showed that the RNase A@C-dots could effectively inhibit the growth of MGC-803 cells. Intra-tumor injection test of RNase A@C-dots showed that RNase A@C-dots could be used for imaging in vivo gastric cancer cells. In conclusion, the as-prepared RNase A@C-dots are suitable for simultaneous therapy and in vivo fluorescence imaging of nude mice loaded with gastric cancer or other tumors.

Effect of sodium ferulate on delayed rectifier K+ currents in PC12 cells

In order to investigate the effect of sodium ferulate (SF) on voltage-activated K⁺ channels, the delayed rectifier K⁺ current (Ik) in PC12 rat pheochromocytoma cells was recorded using the automated patch-clamp method. The results indicated that following the application of SF, the Ik in PC12 cells was significantly decreased in a concentration-dependent manner. The analysis of activation kinetic curves and inactivation kinetic curves of Ik showed that SF had an effect on the activation and inactivation kinetics. Following the application of 15.3 μM SF, the activation curve of the Ik of PC12 cells was shifted to positive potentials and the inactivation curve of the Ik of PC12 cells was shifted to negative potentials. This study revealed that the delayed rectifier K⁺ currents of PC12 cells were inhibited following SF treatment in a concentration-dependent manner. The mechanism may be associated with the delayed activation and enhanced inactivation of Ik-associated channels.

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.

Epidemiological characteristics of motor neuron disease in Chinese patients

BACKGROUND

The epidemiology, diagnosis, and treatment of motor neuron disease (MND) in Chinese patients are ill known.

METHODS

A registered study of 461 MND patients was conducted across 10 facilities in 7 Chinese cities from February 2009 to March 2010.

RESULTS

Patients were classified as amyotrophic lateral sclerosis (ALS) (84.4%), progressive bulbar palsy (PBP) (4.1%), progressive muscular atrophy (PMA) (10.4%), or primary lateral sclerosis (PLS) (0.9%). MND was predominant in men (men/women; 1.6:1.0). Mean onset age was 52.6 years, with the highest incidence being observed between 51 and 60 years. Notably, 26.0% of MND patients were employed in forestry, fishery, or animal husbandry industries. Ten cases (2.7%) reported family history of MND, and 54.2% exhibited cervical onset. MND was also associated with head/neck trauma. Non-invasive positive pressure ventilation was the most common supportive therapy.

CONCLUSION

As a novel comprehensive report of a Chinese population, this study reveals that epidemiological characteristics of MND patients were similar to those observed in international populations. MND is age-related, male gender predominant, and may be associated with both environmental and genetic risk factors.

AdLTR2EF1α-FGF2-mediated prevention of fractionated irradiation-induced salivary hypofunction in swine

Patients frequently experience a loss of salivary function following irradiation (IR) for the treatment of an oral cavity and oropharyngeal cancer. Herein, we tested if transfer of fibroblast growth factor-2 (FGF2) cDNA could limit salivary dysfunction after fractionated IR (7.5 or 9 Gy for 5 consecutive days to one parotid gland) in the miniature pig (minipig). Parotid salivary flow rates steadily decreased by 16 weeks post-IR, whereas blood flow in the targeted parotid gland began to decrease ~3 days after beginning IR. By 2 weeks, post-IR salivary blood flow was reduced by 50%, at which point it remained stable for the remainder of the study. The single preadministration of a hybrid serotype 5 adenoviral vector encoding FGF2 (AdLTR2EF1a-FGF2) resulted in the protection of parotid microvascular endothelial cells from IR damage and significantly limited the decline of parotid salivary flow. Our results suggest that a local treatment directed at protecting salivary gland endothelial cells may be beneficial for patients undergoing IR for oral cavity and oropharyngeal cancer.

High-mobility group box 1 inhibition alleviates lupus-like disease in BXSB mice

High-mobility group box 1 protein (HMGB1), a ubiquitous nuclear DNA-binding protein, functions as a potent proinflammatory factor. In this study, we evaluated the effects of HMGB1 inhibition on murine lupus using the lupus-prone model. We treated male BXSB mice with neutralizing anti-HMGB1 monoclonal antibody (HMGB1 mAb) from age 16 weeks to 26 weeks. The control group received the same amount of control IgG. Lupus-prone male BXSB mice treated with HMGB1mAb showed attenuated proteinuria, glomerulonephritis, circulating anti-dsDNA and immune complex deposition. Levels of serum IL-1β, IL-6, IL-17 and IL-18 were also significantly decreased by administration of HMGB1mAb in lupus-prone BXSB mice. HMGB1mAb treatment also decreased the caspase-1 activity in the kidneys of BXSB mice and reduced the mouse mortality. Our study supports that HMGB1 inhibition alleviates lupus-like disease in BXSB mice and might be a potential treatment option for human SLE.

Identification of a novel synonymous mutation in the human β -Ureidopropionase Gene UPB1 affecting pre-mRNA splicing

β-Ureidopropionase is the third enzyme of the pyrimidine degradation pathway and it catalyzes the conversion of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid to β-alanine and β-aminoisobutyric acid, respectively, and ammonia and CO2. To date, only 16 genetically confirmed patients with a complete ß-ureidopropionase deficiency have been reported. Here, we report the clinical, biochemical, and molecular analysis of a newly identified patient with β-ureidopropionase deficiency. Mutation analysis of the UPB1 gene showed that the patient was compound heterozygous for a novel synonymous mutation c.93C >T (p.Gly31Gly) in exon 1 and a previously described missense mutation c.977G >A (p.Arg326Gln) in exon 9. The in silico predicted effect of the synonymous mutation p.Gly31Gly on pre-mRNA splicing was investigated using a minigene approach. Wild-type and the mutated minigene constructs, containing the entire exon 1, intron 1, and exon 2 of UPB1, yielded different splicing products after expression in HEK293 cells. The c.93C >T (p.Gly31Gly) mutation resulted in altered pre-mRNA splicing of the UPB1 minigene construct and a deletion of the last 13 nucleotides of exon 1. This deletion (r.92_104delGCAAGGAACTCAG) results in a frame shift and the generation of a premature stop codon (p.Lys32SerfsX31). Using a minigene approach, we have thus identified the first synonymous mutation in the UPB1 gene, creating a cryptic splice-donor site affecting pre-mRNA splicing.

Comparative transcriptome analysis reveals significant differences in MicroRNA expression and their target genes between adipose and muscular tissues in cattle

The posttranscriptional gene regulation mediated by microRNAs (miRNAs) plays an important role in various species. However, to date limited miRNAs have been reported between fat and muscle tissues in beef cattle. In this paper, 412 known and 22 novel miRNAs in backfat as well as 334 known and 10 novel miRNAs in longissimus thoracis were identified in the Chinese Qinchuan beef cattle. Bta-miR-199a-3p, -154c, -320a and -432 were expressed at higher levels in backfat tissue, while bta-miR-1, -133a, -206, and -378 were also significantly enriched in muscle tissue. Functional analysis revealed that fat-enriched miRNAs targeted PRKAA1/2, PPARA and PPARG genes to modulate lipid and fatty acid metabolism, and muscle-enriched miRNAs targeted CSRP3 gene to present function involved in skeletal and muscular system development. The results obtained may help in the design of new selection strategies to improve beef quality.

A novel microbead-based microfluidic device for rapid bacterial identification and antibiotic susceptibility testing

Effective treatment of infectious diseases depends on the ability to rapidly identify the infecting bacteria and the use of sensitive antibiotics. The currently used identification assays usually take more than 72 h to perform and have a low sensitivity. Herein, we present a microbead-based microfluidic platform that is highly sensitive and rapid for bacterial detection and antibiotic sensitivity testing. The platform includes four units, one of which is used for bacterial identification and the other three are used for susceptibility testing. Our results showed that Escherichia coli O157 at a cell density range of 10(1)-10(5) CFU/μL could be detected within 30 min. Additionally, the effects of three antibiotics on E. coli O157 were evaluated within 4-8 h. Overall, this integrated microbead-based microdevice provides a sensitive, rapid, reliable, and highly effective platform for the identification of bacteria, as well as antibiotic sensitivity testing.

Detection of fetal sex chromosome aneuploidy by massively parallel sequencing of maternal plasma DNA: initial experience in a Chinese hospital

OBJECTIVES

To evaluate the performance of a massively parallel sequencing (MPS)-based test in detecting fetal sex chromosome aneuploidy (SCA) and to present a comprehensive clinical counseling protocol for SCA-positive patients.

METHODS

This was a retrospective study in a large patient cohort of 5950 singleton pregnancies which underwent MPS-based testing as a prenatal screening test for trisomies 21, 18 and 13, with X and Y chromosomes as secondary findings, in Southwest Hospital in China. MPS-based SCA-positive women were offered the choice of knowing whether their SCA results were positive and those who did commenced a two-stage post-test clinical counseling protocol. In Stage 1, general information about SCA was given, and women were given the option of invasive testing for confirmation of findings; in Stage 2, those who had chosen to undergo invasive testing were informed about the specific SCA affecting their fetus and their management options.

RESULTS

Thirty-three cases were classified as SCA-positive by MPS-based testing. After Stage 1 of the two-stage post-test clinical counseling session, 33 (100%) of these pregnant women chose to know the screening test results, and 25 (75.76%) underwent an invasive diagnostic procedure and karyotype analysis, in one of whom karyotyping failed. In thirteen cases, karyotyping confirmed the MPS-based test results (two X0 cases, seven XXX cases, three XXY cases and one XYY case), giving a positive predictive value of 54.17% (13/24 cases confirmed by karyotyping). After post-test clinical counseling session Stage 2, seven women chose to terminate the pregnancy: one X0 case, two XXX cases, the three XXY cases and the single XYY case. Six women decided to continue with pregnancy: one X0 case and five XXX cases.

CONCLUSION

Our study showed the feasibility of clinical application of the MPS-based test in the non-invasive detection of fetal SCA. Together with a two-stage post-test clinical counseling protocol, it leads to a well-informed decision-making procedure.