[Clinical efficacy of local injection of platelet-rich plasma combined with double-layer artificial dermis in treating wounds with exposed tendon on extremity]

Objective: To investigate the clinical efficacy of local injection of platelet-rich plasma (PRP) combined with double-layer artificial dermis in treating wounds with exposed tendon on extremity. Methods: A retrospective observational study was conducted. From December 2017 to October 2022, 16 patients were admitted to Department of Orthopaedic Trauma of the Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, and 32 patients were admitted to Department of Burns and Plastic Surgery of Guiyang Steel Factory Staff Hospital. All the patients had wounds with exposed tendon on extremity caused by various reasons and met the inclusion criteria. There were 39 males and 9 females, aged 26 to 58 years. The patients were divided into PRP alone group, artificial dermis alone group, and PRP+artificial dermis group, with 16 patients in each group. The wounds were treated with autologous PRP, double-layer artificial dermis, or thei combination of autologous PRP and double-layer artificial dermis, followed by autologous split-thickness scalp grafting after good growth of granulation tissue. On the 7th day after the secondary surgery, the autograft survival was observed, and the survival rate was calculated. The wound healing time and length of hospital stay of patients were recorded. At 3 and 6 months after wound healing, the Vancouver scar scale (VSS) was used to score the pigmentation, height, vascularity, and pliability of scars, and the total score was calculated. Adverse reactions during the entire treatment process were recorded. Data were statistically analyzed with chi-square test, Fisher's exact probability test, one-way analysis of variance, least significant difference test, Kruskal-Wallis H test, Nemenyi test, and Bonferroni correction. Results: On the 7th day after the secondary surgery, there was no statistically significant difference in the autograft survival rate of patients among PRP alone group, artificial dermis alone group, and PRP+artificial dermis group (P>0.05). The wound healing time and length of hospital stay of patients in PRP+artificial dermis group were (20.1±3.0) and (24±4) d, respectively, which were significantly shorter than (24.4±5.5) and (30±8) d in PRP alone group (P<0.05) and (24.8±4.9) and (32±8) d in artificial dermis alone group (P<0.05). At 3 and 6 months after wound healing, the pliability scores of patients in PRP+artificial dermis group were significantly lower than those in PRP alone group (with Z values of 12.91 and 15.69, respectively, P<0.05) and artificial dermis alone group (with Z values of 12.50 and 12.91, respectively, P<0.05). There were no statistically significant differences in pigmentation, vascularity, height scores, and total score of scar of patients among the three groups (P>0.05). In artificial dermis alone group, one patient experienced partial liquefaction and detachment of the double-layer artificial dermis due to local infection of Staphylococcus epidermidis, which received wound dressing change, second artificial dermis transplantation, and subsequent treatment as before. No adverse reactions occurred in the remaining patients during the whole treatment process. Conclusions: Local injection of PRP combined with double-layer artificial dermis is effective in treating wounds with exposed tendon on extremity, which can not only significantly shorten wound healing time and length of hospital stay, but also improve scar pliability after wound healing to some extent in the long term. It is a clinically valuable treatment technique that is worth promoting and applying.

Epithelial cell adhesion molecule (EpCAM) regulates HGFR signaling to promote colon cancer progression and metastasis

BACKGROUND

Epithelial cell adhesion molecule (EpCAM) is known to highly expression and promotes cancer progression in many cancer types, including colorectal cancer. While metastasis is one of the main causes of cancer treatment failure, the involvement of EpCAM signaling in metastatic processes is unclear. We propose the potential crosstalk of EpCAM signaling with the HGFR signaling in order to govern metastatic activity in colorectal cancer.

METHODS

Immunoprecipitation (IP), enzyme-linked immunosorbent assay (ELISA), and fluorescence resonance energy transfer (FRET) was conducted to explore the extracellular domain of EpCAM (EpEX) and HGFR interaction. Western blotting was taken to determine the expression of proteins in colorectal cancer (CRC) cell lines. The functions of EpEX in CRC were investigated by proliferation, migration, and invasion analysis. The combined therapy was validated via a tail vein injection method for the metastasis and orthotopic colon cancer models.

RESULTS

This study demonstrates that the EpEX binds to HGFR and induces downstream signaling in colon cancer cells. Moreover, EpEX and HGF cooperatively mediate HGFR signaling. Furthermore, EpEX enhances the epithelial-to-mesenchymal transition and metastatic potential of colon cancer cells by activating ERK and FAK-AKT signaling pathways, and it further stabilizes active β-catenin and Snail proteins by decreasing GSK3β activity. Finally, we show that the combined treatment of an anti-EpCAM neutralizing antibody (EpAb2-6) and an HGFR inhibitor (crizotinib) significantly inhibits tumor progression and prolongs survival in metastatic and orthotopic animal models of colon cancer.

CONCLUSION

Our findings illuminate the molecular mechanisms underlying EpCAM signaling promotion of colon cancer metastasis, further suggesting that the combination of EpAb2-6 and crizotinib may be an effective strategy for treating cancer patients with high EpCAM expression.

Integrated genomic analysis to identify druggable targets for pancreatic cancer

According to the National Comprehensive Cancer Network and the American Society of Clinical Oncology, the standard treatment for pancreatic cancer (PC) is gemcitabine and fluorouracil. Other chemotherapeutic agents have been widely combined. However, drug resistance remains a huge challenge, leading to the ineffectiveness of cancer therapy. Therefore, we are trying to discover new treatments for PC by utilizing genomic information to identify PC-associated genes as well as drug target genes for drug repurposing. Genomic information from a public database, the cBio Cancer Genomics Portal, was employed to retrieve the somatic mutation genes of PC. Five functional annotations were applied to prioritize the PC risk genes: Kyoto Encyclopedia of Genes and Genomes; biological process; knockout mouse; Gene List Automatically Derived For You; and Gene Expression Omnibus Dataset. DrugBank database was utilized to extract PC drug targets. To narrow down the most promising drugs for PC, CMap Touchstone analysis was applied. Finally, ClinicalTrials.gov and a literature review were used to screen the potential drugs under clinical and preclinical investigation. Here, we extracted 895 PC-associated genes according to the cBioPortal database and prioritized them by using five functional annotations; 318 genes were assigned as biological PC risk genes. Further, 216 genes were druggable according to the DrugBank database. CMap Touchstone analysis indicated 13 candidate drugs for PC. Among those 13 drugs, 8 drugs are in the clinical trials, 2 drugs were supported by the preclinical studies, and 3 drugs are with no evidence status for PC. Importantly, we found that midostaurin (targeted PRKA) and fulvestrant (targeted ESR1) are promising candidate drugs for PC treatment based on the genomic-driven drug repurposing pipelines. In short, integrated analysis using a genomic information database demonstrated the viability for drug repurposing. We proposed two drugs (midostaurin and fulvestrant) as promising drugs for PC.

2,6-Difluorobenzamide derivatives as store-operated calcium channel (SOC) inhibitors

The Ca²⁺ entry from store-operated Ca²⁺ channel (SOC) is involved in regulating colorectal cancer progression, such as cell migration. SOC activation is due to STIM1 translocation and interaction with Orai1 upon Ca²⁺ depletion in the ER. Numerous SOC inhibitors, like 2-APB, have been developed and demonstrated their inhibition effects in the preclinical stage. However, most currently used SOC inhibitors have higher cytotoxicity or opposite effects at different doses, and the drugs to target SOC in the clinic are lacking. In this study, a total of 13 difluorobenzamide compounds had been synthesized and examined the inhibitory effects on SOC with Ca²⁺ imaging and wound-healing migration assay. Among them, 2,6-Difluoro-N-(5-(4-fluorophenyl)pyridine-2-yl)benzamide (MPT0M004, 8a) demonstrated a prominent inhibitory ability on SOC. Furthermore, the cell proliferation assay results showed that MPT0M004 (8a) had lower cytotoxicity than 2-APB, the reference compound. In the pharmacokinetic study, MPT0M004 (8a) has a long half-life (T_1/2 = 24 h) and lower daily dose administered intravenously with an oral bioavailability (F = 34%). Therefore, MPT0M004 (8a) has the potential to be a lead compound as a SOC inhibitor and further develop into a potential drug to treat colorectal cancer.

Human rs75776403 polymorphism links differential phenotypic and clinical outcomes to a CLEC18A p.T151M-driven multiomics

BACKGROUND

Human traits, diseases susceptibility, and clinical outcomes vary hugely among individuals. Despite a fundamental understanding of genetic (or environmental) contributions, the detailed mechanisms of how genetic variation impacts molecular or cellular behaviours of a gene, and subsequently leads to such variability remain poorly understood.

METHODS

Here, in addition to phenome-wide correlations, we leveraged multiomics to exploit mechanistic links, from genetic polymorphism to protein structural or functional changes and a cross-omics perturbation landscape of a germline variant.

RESULTS

We identified a missense cis-acting expression quantitative trait locus in CLEC18A (rs75776403) in which the altered residue (T₁₅₁→M₁₅₁) disrupts the lipid-binding ability of the protein domain. The altered allele carriage led to a metabolic and proliferative shift, as well as immune deactivation, therefore determines human anthropometrics (body height), kidney, and hematological traits.

CONCLUSIONS

Collectively, we uncovered genetic pleiotropy in human complex traits and diseases via CLEC18A rs75776403-regulated pathways.

Aspirin and Sulindac act via different mechanisms to inhibit store-operated calcium channel: Implications for colorectal cancer metastasis

Store-operated Ca²⁺ channel (SOC)-regulated Ca²⁺ entry is involved in inflammation and colorectal cancer (CRC) progression, but clinically applicable treatments targeting this mechanism are lacking. Recent studies have shown that nonsteroidal anti-inflammatory drugs (NSAIDs) not only inhibit inflammation but they also suppress Ca²⁺ entry via SOC (SOCE). Therefore, delineating the mechanisms of SOCE inhibition by NSAIDs may lead to new CRC treatments. In this study, we tested eight candidate NSAIDs in Ca²⁺ imaging experiments and found that Aspirin and Sulindac were the most effective at suppressing SOCE. Furthermore, time-lapse FRET imaging using TIRF microscopy and ground state depletion (GSD) super-resolution (SR) imaging revealed that SOC was inhibited by Aspirin and Sulindac via different mechanisms. Aspirin quickly interrupted the STIM1-Orai1 interaction, whereas Sulindac mainly suppressed STIM1 translocation. Additionally, Aspirin and Sulindac both inhibited metastasis-related endpoints in CRC cells. Both drugs were used throughout the study at doses that suppressed CRC cell migration and invasion without altering cell survival. This is the first study to reveal the differential inhibitory mechanisms of Aspirin and Sulindac on SOC activity. Thus, our results shed new light on the therapeutic potential of Aspirin for CRC and SOCE-related diseases.

Social interactions upregulate hemolymph tryptophan and tyrosine levels in the male lobster cockroach

In the present study, we found that tryptophan (TRP) and tyrosine (TYR) levels are increased in hemolymph of male Nauphoeta cinerea after social contact with either male or female conspecifics. Hemolymph was collected from individual males before and after the social interactions, and samples were analyzed by HPLC-ECD; analyte identities were confirmed by UPLC/MS. After a male-male first encounter fight, hemolymph TRP and TYR levels were significantly increased in dominants compared with the levels before the encounter. Conversely, TRP and TYR in subordinates were maintained at levels similar to those before the encounter. While after-fight TRP and TYR levels were significantly higher in dominants than subordinates, no significant differences were found in the contestants before the fight. Moreover, contact with an isolated male antenna was sufficient to stimulate attack behavior and increase hemolymph TRP and TYR titers to levels similar to those seen in dominants. After a male-female interaction, two distinct outcomes could be observed. Either hemolymph TRP and TYR levels were increased in successfully mated males, or TRP and TYR levels were unchanged in males that only exhibited premating wing-raising behavior but failed in mating. After contacting the antenna of a socially naïve male with an isolated female antenna, three patterns of behavior and related amino acid response were observed: 1) only premating wing-raising behavior with significant increase of TRP and TYR levels, 2) only attack behavior with significant increase of TRP and TYR levels, and 3) mixed wing-raising and attack behaviors with no significant changes in TRP and TYR levels. The present results show a robust response of hemolymph TRP and TYR to social contact. In light of previously characterized responses in pheromone and juvenile hormone levels, these amine responses suggest that the physiological response of N. cinerea to social contact is multi-dimensional.

[A multicentric study on clinical characteristics and antibiotic sensitivity in children with methicillin-resistant Staphylococcus aureus infection]

Objective: To investigate the clinical characteristics of pediatric methicillin-resistant Staphylococcus aureus (MRSA) infection and the antibiotic sensitivity of the isolates. Methods: The clinical data of children with MRSA infection and antibiotic sensitivity of the isolates from 11 children's hospitals in Infectious Diseases Surveillance of Paediatrics (ISPED) group of China between January 1, 2018 and December 31, 2018 were collected retrospectively. The children's general condition, high-risk factors, antimicrobial therapy and prognosis, differences in clinical disease and laboratory test results between different age groups, and differences of antibiotic sensitivity between community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA were analyzed. The t test and Wilcoxon rank sum test were used for statistical analysis of the quantitative data and Chi-square test were used for comparison of rates. Results: Among the 452 patients, 264 were males and 188 were females, aged from 2 days to 17 years. There were 233 cases (51.5%) in the ≤1 year old group, 79 cases (17.5%) in the>1-3 years old group, 29 cases (6.4%) in the >3-5 years old group, 65 cases (14.4%) in the >5-10 years old group, and 46 cases (10.2%) in the>10 years old group. The main distributions of onset seasons were 55 cases (12.2%) in December, 47 cases (10.4%) in February, 46 cases (10.2%) in November, 45 cases (10.0%) in January, 40 cases (8.8%) in March. There were 335 cases (74.1%) CA-MRSA and 117 (25.9%) cases HA-MRSA. Among all cases, 174 cases (38.5%) had basic diseases or long-term use of hormone and immunosuppressive drugs. During the period of hospitalization, 209 cases (46.2%) received medical interventions. There were 182 patients (40.3%) had used antibiotics (β-lactams, glycopeptides, macrolides, carbapenems, oxazolones, sulfonamides etc) 3 months before admission. The most common clinical disease was pneumonia (203 cases), followed by skin soft-tissue infection (133 cases), sepsis (92 cases), deep tissue abscess (42 cases), osteomyelitis (40 cases), and septic arthritis (26 cases), suppurative meningitis (10 cases). The proportion of pneumonia in the ≤1 year old group was higher than the >1-3 years old group,>3-5 years old group,>5-10 years old group,>10 years old group (57.5% (134/233) vs. 30.4% (24/79), 31.0% (9/29), 38.5% (25/65), 23.9% (11/46), χ(2)=17.374, 7.293, 7.410, 17.373, all P<0.01) The proportion of skin and soft tissue infections caused by CA-MRSA infection was higher than HA-MRSA (33.4% (112/335) vs. 17.9% (21/117), χ(2)=10.010, P=0.002), and the proportion of pneumonia caused by HA-MRSA infection was higher than CA-MRSA (53.0% (62/117) vs. 42.1% (141/335), χ(2)=4.166, P=0.041). The first white blood cell count of the ≤1 year old group was higher than that children > 1 year old ((15±8)×10(9)/L vs. (13±7)×10(9)/L, t=2.697, P=0.007), while the C-reactive protein of the ≤1 year old group was lower than the 1-3 years old group,>5-10 years old group,>10 years old group (8.00 (0.04-194.00) vs.17.00 (0.50-316.00), 15.20 (0.23-312.00), 21.79(0.13-219.00) mg/L, Z=3.207, 2.044, 2.513, all P<0.05), there were no significant differences in procalcitonin (PCT) between different age groups (all P>0.05). After the treatment, 131 cases were cured, 278 cases were improved, 21 cases were not cured, 12 cases died, and 10 cases were abandoned. The 452 MRSA isolates were all sensitive to vancomycin (100.0%), linezolid (100.0%), 100.0% resistant to penicillin, highly resistant to erythromycin (85.0%, 375/441), clindamycin (67.7%, 294/434), less resistant to sulfonamides (5.9%, 23/391), levofloxacin (4.5%, 19/423), gentamicin (3.2%, 14/438), rifampicin (1.8%, 8/440), minocycline (1.1%, 1/91). The antimicrobial resistance rates were not significantly different between the CA-MRSA and HA-MRSA groups (all P>0.05). Conclusions: The infection of MRSA is mainly found in infants under 3 years old. The prevalent seasons are winter and spring, and MRSA is mainly acquired in the community. The main clinical diseases are pneumonia, skin soft-tissue infection and sepsis. No MRSA isolate is resistant to vancomycin, linezolid. MRSA isolates are generally sensitive to sulfonamides, levofloxacin, gentamicin, rifampicin, minocycline, and were highly resistant to erythromycin and clindamycin. To achieve better prognosis. clinicians should initiate anti-infective treatment for children with MRSA infection according to the clinical characteristics of patients and drug sensitivity of the isolates timely and effectively.

Best practices in near-infrared fluorescence imaging with indocyanine green (NIRF/ICG)-guided robotic urologic surgery: a systematic review-based expert consensus

PURPOSE

The aim of the present study is to investigate the impact of the near-infrared (NIRF) technology with indocyanine green (ICG) in robotic urologic surgery by performing a systematic literature review and to provide evidence-based expert recommendations on best practices in this field.

METHODS

All English language publications on NIRF/ICG-guided robotic urologic procedures were evaluated. We followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) statement to evaluate PubMed^®, Scopus^® and Web of Science™ databases (up to April 2019). Experts in the field provided detailed pictures and intraoperative video-clips of different NIRF/ICG-guided robotic surgeries with recommendations for each procedure. A unique QRcode was generated and linked to each underlying video-clip. This new exclusive feature makes the present the first "dynamic paper" that merges text and figure description with their own video providing readers an innovative, immersive, high-quality and user-friendly experience.

RESULTS

Our electronic search identified a total of 576 papers. Of these, 36 studies included in the present systematic review reporting the use of NIRF/ICG in robotic partial nephrectomy (n = 13), robotic radical prostatectomy and lymphadenectomy (n = 7), robotic ureteral re-implantation and reconstruction (n = 5), robotic adrenalectomy (n = 4), robotic radical cystectomy (n = 3), penectomy and robotic inguinal lymphadenectomy (n = 2), robotic simple prostatectomy (n = 1), robotic kidney transplantation (n = 1) and robotic sacrocolpopexy (n = 1).

CONCLUSION

NIRF/ICG technology has now emerged as a safe, feasible and useful tool that may facilitate urologic robotic surgery. It has been shown to improve the identification of key anatomical landmarks and pathological structures for oncological and non-oncological procedures. Level of evidence is predominantly low. Larger series with longer follow-up are needed, especially in assessing the quality of the nodal dissection and the feasibility of the identification of sentinel nodes and the impact of these novel technologies on long-term oncological and functional outcomes.

Znf179 E3 ligase-mediated TDP-43 polyubiquitination is involved in TDP-43- ubiquitinated inclusions (UBI) (+)-related neurodegenerative pathology

Background

The brain predominantly expressed RING finger protein, Znf179, is known to be important for embryonic neuronal differentiation during brain development. Downregulation of Znf179 has been observed in motor neurons of adult mouse models for amyotrophic lateral sclerosis (ALS), yet the molecular function of Znf179 in neurodegeneration has never been previously described. Znf179 contains the classical C3HC4 RING finger domain, and numerous proteins containing C3HC4 RING finger domain act as E3 ubiquitin ligases. Hence, we are interested to identify whether Znf179 possesses E3 ligase activity and its role in ALS neuropathy.

Methods

We used in vivo and in vitro ubiquitination assay to examine the E3 ligase autoubiquitination activity of Znf179 and its effect on 26S proteasome activity. To search for the candidate substrates of Znf179, we immunoprecipitated Znf179 and subjected to mass spectrometry (MS) analysis to identify its interacting proteins. We found that ALS/ FTLD-U (frontotemporal lobar degeneration (FTLD) with ubiquitin inclusions)-related neurodegenerative TDP-43 protein is the E3 ligase substrate of Znf179. To further clarify the role of E3 ubiquitin ligase Znf179 in neurodegenerative TDP-43-UBI (ubiquitinated inclusions) (+) proteinopathy, the effect of Znf179-mediated TDP-43 polyubiquitination on TDP-43 protein stability, aggregate formation and nucleus/cytoplasm mislocalization were evaluated in vitro cell culture system and in vivo animal model.

Results

Here we report that Znf179 is a RING E3 ubiquitin ligase which possesses autoubiquitination feature and regulates 26S proteasome activity through modulating the protein expression levels of 19S/20S proteasome subunits. Our immunoprecipitation assay and MS analysis results revealed that the neuropathological TDP-43 protein is one of its E3 ligase substrate. Znf179 interactes with TDP-43 protein and mediates polyubiquitination of TDP-43 in vitro and in vivo. In neurodegenerative TDP-43 proteinopathy, we found that Znf179-mediated polyubiquitination of TDP-43 accelerates its protein turnover rate and attenuates insoluble pathologic TDP-43 aggregates, while knockout of Znf179 in mouse brain results in accumulation of insoluble TDP-43 and cytosolic TDP-43 inclusions in cortex, hippocampus and midbrain regions.

Conclusions

Here we unveil the important role for the novel E3 ligase Znf179 in TDP-43-mediated neuropathy, and provide a potential therapeutic strategy for combating ALS/ FTLD-U neurodegenerative pathologies.

Electronic supplementary material

The online version of this article (10.1186/s12929-018-0479-4) contains supplementary material, which is available to authorized users.

Skeletal muscle in aged mice reveals extensive transformation of muscle gene expression

BACKGROUND

Aging leads to decreased skeletal muscle function in mammals and is associated with a progressive loss of muscle mass, quality and strength. Age-related muscle loss (sarcopenia) is an important health problem associated with the aged population.

RESULTS

We investigated the alteration of genome-wide transcription in mouse skeletal muscle tissue (rectus femoris muscle) during aging using a high-throughput sequencing technique. Analysis revealed significant transcriptional changes between skeletal muscles of mice at 3 (young group) and 24 (old group) months of age. Specifically, genes associated with energy metabolism, cell proliferation, muscle myosin isoforms, as well as immune functions were found to be altered. We observed several interesting gene expression changes in the elderly, many of which have not been reported before.

CONCLUSIONS

Those data expand our understanding of the various compensatory mechanisms that can occur with age, and further will assist in the development of methods to prevent and attenuate adverse outcomes of aging.

Abstract 85: Oleic acid promotes head and neck squamous cell carcinoma anoikis resistance and metastasis via ANGPTL4/fibronectin pathway

Obese patients have higher levels of free fatty acids (FFAs) in their plasma and a higher risk of cancer than their non-obese counterparts. However, the mechanisms involved in the regulation of cancer metastasis by FFAs remain unclear. In this study, we found that oleic acid (OA) induced angiopoietin-like 4 (ANGPTL4) protein expression and secretion and conferred anoikis resistance to head and neck squamous cell carcinomas (HNSCCs). The autocrine production of OA-induced ANGPTL4 further promoted HNSCC migration and invasion. In addition, the expression of peroxisome proliferator-activated receptor (PPAR) was essential for the OA-induced ANGPTL4 expression and invasion. The levels of OA-induced epithelial-mesenchymal transition markers, such as vimentin, MMP-9, and fibronectin and its downstream effectors Rac1/Cdc42, were significantly reduced in ANGPTL4-depleted cells. Knocking down fibronectin not only inhibited the expression of MMP-9 but also repressed OA- and recombinant ANGPTL4-induced HNSCC invasion. On the other hand, ANGPTL4 siRNA inhibited OA-induced MMP-9 expression, which was reversed in fibronectin-overexpressing cells. Furthermore, the depletion of ANGPTL4 impeded the OA-primed metastatic seeding of tumor cells in the lungs. These results demonstrate that OA enhances HNSCC metastasis through the ANGPTL4/fibronectin/Rac1/Cdc42 and ANGPTL4/fibronectin/MMP-9 signaling axes. The inhibition of ANGPTL4 could be a potential strategy for the treatment of FFA-mediated HNSCC metastasis.

Citation Format: Chih-Jie Shen, Shih-Hung Chan, Chung-Ta Lee, Wan-Chen Huang, Jhih-Peng Tsai, Kwang-Yu Chang, Wen-Chang Chang, Ben-Kuen Chen. Oleic acid promotes head and neck squamous cell carcinoma anoikis resistance and metastasis via ANGPTL4/fibronectin pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 85.

Single-molecule Förster resonance energy transfer (FRET) analysis discloses the dynamics of the DNA-topoisomerase II (Top2) interaction in the presence of TOP2-targeting agents

Topoisomerases play crucial roles in DNA replication, transcription, and recombination. For instance, topoisomerase II (Top2) is critically important for resolving DNA tangles during cell division, and as such, it is a broad anticancer drug target. Top2 regulates DNA topology by transiently breaking one double-stranded DNA molecule (cleavage), allowing a second double strand to pass through the opened DNA gate (opening), and then closing the gate by rejoining the broken ends. Drugs that modulate Top2 catalysis may therefore affect enzymatic activity at several different steps. Previous studies have focused on examining DNA cleavage and ligation; however, the dynamic opening and closing of the DNA gate has been less explored. Here, we used the single-molecule Förster resonance energy transfer (smFRET) method to observe the open and closed state of the DNA gate and to measure dwell times in each state. Our results show that Top2 binds and bends DNA to increase the energy transfer efficiency (E_FRET), and ATP treatment further induces the fluctuation of E_FRET, representing the gate opening and closing. Additionally, our results demonstrate that both types of Top2-targeting anticancer drugs, the catalytic inhibitor dexrazoxane (ICRF187) and mechanistic poison teniposide (VM26), can interfere with DNA gate dynamics and shorten the dwell time in the closed state. Moreover, Top2 bound to the nonhydrolyzable ATP analog 5'-adenylyl-β,γ-imidodiphosphate exhibits altered DNA gate dynamics, but the DNA gate appears to open and close even after N-gate closure. In summary, we have utilized single-molecule detection to unravel Top2 DNA gate dynamics and reveal previously unknown effects of Top2 drugs on these dynamics.

Oleic acid-induced ANGPTL4 enhances head and neck squamous cell carcinoma anoikis resistance and metastasis via up-regulation of fibronectin

Obese patients have higher levels of free fatty acids (FFAs) in their plasma and a higher risk of cancer than their non-obese counterparts. However, the mechanisms involved in the regulation of cancer metastasis by FFAs remain unclear. In this study, we found that oleic acid (OA) induced angiopoietin-like 4 (ANGPTL4) protein expression and secretion and conferred anoikis resistance to head and neck squamous cell carcinomas (HNSCCs). The autocrine production of OA-induced ANGPTL4 further promoted HNSCC migration and invasion. In addition, the expression of peroxisome proliferator-activated receptor (PPAR) was essential for the OA-induced ANGPTL4 expression and invasion. The levels of OA-induced epithelial-mesenchymal transition markers, such as vimentin, MMP-9, and fibronectin and its downstream effectors Rac1/Cdc42, were significantly reduced in ANGPTL4-depleted cells. Knocking down fibronectin inhibited the expression of MMP-9 and repressed OA- and recombinant ANGPTL4-induced HNSCC invasion. On the other hand, ANGPTL4 siRNA inhibited OA-induced MMP-9 expression, which was reversed in fibronectin-overexpressing cells. Furthermore, the depletion of ANGPTL4 impeded the OA-primed metastatic seeding of tumor cells in the lungs. These results demonstrate that OA enhances HNSCC metastasis through the ANGPTL4/fibronectin/Rac1/Cdc42 and ANGPTL4/fibronectin/MMP-9 signaling axes.

Characterization of cytokinome landscape for clinical responses in human cancers

Dysfunctional intratumoral immune reactions are shaped by complex networks of cytokines (including chemokines), and how the cytokinome landscape coordinates with tumors has not been systematically investigated. Using high-dimensional datasets of cancer specimens, we explored the transcript abundance, biomarker potential, and prognostic impact of local cytokines across 19 tumor types. We found that most cytokines are highly locally dysregulated (p = 0.024), revealing spatiotemporal pattern of local cytokines in the development of cancers. In addition, we noted the significant downregulation of CCL14 and CXCL12 in 9 and 10 cancer types, respectively, implying their crucial roles in tumor pathogenesis. We also found that cytokines showed significantly higher specificity properties compared to other protein-coding genes (PCGs) in primary tumor specimens (p << 0.001), indicating that tissue context remains an issue when considering cancer cytokinomes. Finally, we linked concentrations of local cytokines to patient survival. Our results thus provide a panoramic view of pan-cancer cytokinomes, which highlights tumor type specificity of cancer-related cytokines and their impacts on disease prognosis.

Development of a chitosan-based tissue-engineered renal proximal tubule conduit

Renal proximal tubule cells (RPTCs) are responsible for glomerular filtration and maintenance of water/electrolyte balance. To regenerate a proximal tubule, sufficient cell numbers and normal cell function are requisite. Collagen has been routinely used as a substrate for culturing human RPTCs (HRPTCs); however, the role of biomaterials has not been thoroughly explored. In this study, RPTCs retrieved from human nephrectomy/nephroureterectomy specimens were cultivated on chitosan as a substrate in serum-free condition for up to 150 days. HRPTCs could maintain a typical epithelial morphology and the specific differentiation feature of transporting epithelia after such long-term culture. As compared with HRPTCs cultivated on collagen, those cultivated on chitosan showed more dome formation, higher Na⁺ -K⁺ ATPase expression, lower vimentin expression, and lower transepithelial electrical resistance, indicating that HRPTCs cultivated on chitosan presented better differentiation status and would be more functional with better active transportation. Thus, the current study indicates greater scope for the use of chitosan as a biomaterial for preparing a HRPTC-coated chitosan conduit, which might be useful for the scaffold design of tissue-engineered proximal tubules. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 9-20, 2018.

PTX3 gene activation in EGF-induced head and neck cancer cell metastasis

Overexpression of the epidermal growth factor (EGF) receptor (EGFR) is associated with enhanced invasion and metastasis in head and neck squamous cell carcinoma (HNSCC). Long Pentraxin PTX3 is involved in immune escape in cancer cells. Here, we identified PTX3 as a promoting factor that mediates EGF-induced HNSCC metastasis. EGF-induced PTX3 transcriptional activation is via the binding of c-Jun to the activator protein (AP)-1 binding site of the PTX3 promoter. PI3K/Akt and NF-κB were essential for the PTX3 activation. EGF-induced PTX3 expression was blocked in c-Jun- and NF-κB-knockdown cells. EGF-mediated PTX3 secretion resulted in the enhancement of cell migration and invasion, and interactions between cancer and endothelial cells. The tail-vein injection animal model revealed that depletion of PTX3 decreased EGF-primed tumor cell metastatic seeding of the lungs. In addition, fibronectin, matrix metalloproteinase-9 (MMP9) and E-cadherin were essential components in EGFR/PTX3-mediated cancer metastasis. In conclusion, PI3K/Akt and NF-κB-dependent regulation of AP-1 mediates PTX3 transcriptional responses to EGF. Autocrine production of EGF-induced PTX3 in turn induces metastatic molecules, activating inflammatory cascades and metastasis.

Dynamic response of HPV16/anti-HPV16 pairs with unbinding events studied by atomic force microscopy

This paper proposes an effective approach to distinguish whether samples include Human Papilloma virus type-16 (HPV16) by Atomic force microscopy (AFM). AFM is an important instrument in nanobiotechnology field. At first we identified the HPV16 by Polymerase chain reaction (PCR) analysis and Western blotting from specimen of the HPV patient (E12) and the normal (C2), and then we used an AFM to observe the surface ultrastructure by tapping mode and to measure the unbinding force between HPV16 coupled to an AFM tip and anti-HPV16 L1 coated on the substrate surface by contact mode. The experimental results by tapping mode show that the size of a single HPV viron was similar to its SEM image from the previous literatures; moreover, based on the purposed methods and the analysis, two obvious findings that we can determine whether or not the subject is a HPV patient can be derived from the results; one is based on the distribution of unbinding forces, and the other is based on the distribution of the stiffness. Furthermore, the proposed method could be a useful technique for further investigating the potential role among subtypes of HPVs in the oncogenesis of human cervical cancer.

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Human Papilloma virus type-16 (HPV16) particles were observed by AFM tapping mode and contact mode.

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This study develops a convenient procedure by AFM to check HPV16 samples under test.

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This procedure by AFM could be used to design the HPV16 biosensor.

Gene expression profiling combined with functional analysis identify integrin beta1 (ITGB1) as a potential prognosis biomarker in triple negative breast cancer

Triple negative breast cancer (TNBC) accounts for approximately 15-20% of all types of breast cancer, and treatment is still limited. This type of breast cancer shows a high risk of recurrence, visceral metastasis, a worse prognosis, and shorter distant metastasis-free survival. Several studies have been reported that genetics factors are associated with breast cancer disease progression and patients' survival. In this study, we combined Taiwanese microarray data from the GEO database and The Cancer Genome Atlas (TCGA) database to study the role of Integrin Beta1 (ITGB1) in TNBC. Two triple negative breast cancer cell lines (MDA-MB-231; MDA-MB-468) were used to validate the functions of ITGB1. We found that a higher ITGB1 gene expression level was associated to lower survival. Silencing of ITGB1 inhibited TNBC cell migration, invasion and store-operated calcium influx. Our study provided a potential candidate biomarker for breast cancer cells migration, invasion and TNBC patients' survival.

Progenitor-like cells derived from mouse kidney protect against renal fibrosis in a remnant kidney model via decreased endothelial mesenchymal transition

Introduction

Pathophysiological changes associated with chronic kidney disease impair angiogenic processes and increase renal fibrosis. Progenitor-like cells derived from adult kidney have been previously used to promote regeneration in acute kidney injury, even though it remained unclear whether the cells could be beneficial in chronic kidney disease (CKD).

Methods

In this study, we established a CKD model by five-sixths nephrectomy and mouse kidney progenitor-like cells (MKPCs) were intravenously administered weekly for 5 weeks after establishing CKD. We examined the impact of MKPCs on the progression of renal fibrosis and the potential of MKPCs to preserve the angiogenic process and prevent endothelial mesenchymal transition in vivo and in vitro.

Results

Our results demonstrate that the MKPCs delayed interstitial fibrosis and the progression of glomerular sclerosis and ameliorated the decline of kidney function. At 17 weeks, the treated mice exhibited lower blood pressures, higher hematocrit levels, and larger kidney sizes than the control mice. In addition, the MKPC treatment prolonged the survival of the mice with chronic kidney injuries. We observed a decreased recruitment of macrophages and myofibroblasts in the interstitium and the increased tubular proliferation. Notably, MKPC both decreased the level of vascular rarefaction and prevented endothelial mesenchymal transition (EndoMT) in the remnant kidneys. Moreover, the conditioned medium from the MKPCs ameliorated endothelial cell death under hypoxic culture conditions and prevented TGF-β-induced EndoMT through downregulation of phosphorylated Smad 3 in vitro.

Conclusions

MKPCs may be a beneficial treatment for kidney diseases characterized by progressive renal fibrosis. The enhanced preservation of angiogenic processes following MKPC injections may be associated with decreased fibrosis in the remnant kidney. These findings provide further understanding of the mechanisms involved in these processes and will help develop new cell-based therapeutic strategies for regenerative medicine in renal fibrosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0241-8) contains supplementary material, which is available to authorized users.

Acidic FGF promotes neurite outgrowth of cortical neurons and improves neuroprotective effect in a cerebral ischemic rat model

Acidic fibroblast growth factor (aFGF) is a neurotrophic factor which is a powerful neuroprotective and neuroregenerative factor of the nervous system. Prior study had shown that levels of FGFs significantly increase following ischemic injury, reflecting a physiological protection mechanism. However, few reports demonstrated the efficacy of applying aFGF in cerebral ischemia. A recent report showed that the intranasal aFGF treatment improved neurological functional recovery; however, it did not significantly reduce the lesion size in ischemic rats. The present study examines the neuroprotective effect of aFGF on cortical neuron-glial cultures under oxygen glucose deprivation (OGD)-induced cell damage and investigates whether epidural application of slow-released aFGF could improve benefit on ischemic stroke injury in conscious rats. We used a topical application of aFGF mixed in fibrin glue, a slow-release carrier, over the peri-ischemic cortex and examined such treatment on cerebral infarction and behavioral impairments of rats subjected to focal cerebral ischemia (FCI). Results demonstrate that aFGF effectively protected cortical neuron-glial cultures from OGD-induced neuronal damage. Neurite extension from cortical neurons was significantly enhanced by aFGF, mediated through activation of AKT and ERK. In addition, topical application of fibrin glue-mixed aFGF dose-dependently reduced ischemia-induced brain infarction and improved functional restoration in ischemic stroke rats. Slow-released aFGF not only protected hippocampal and cortical cell loss but reduced microglial infiltration in FCI rats. Our results suggest that aFGF mixed in fibrin glue could prolong the protective/regenerative efficacy of aFGF to the damaged brain tissue and thus improve the functional restorative effect of aFGF.

An increase in reactive oxygen species by deregulation of ARNT enhances chemotherapeutic drug-induced cancer cell death

Background

Unique characteristics of tumor microenvironments can be used as targets of cancer therapy. The aryl hydrocarbon receptor nuclear translocator (ARNT) is an important mediator of tumor progression. However, the functional role of ARNT in chemotherapeutic drug-treated cancer remains unclear.

Methodology/Principal Findings

Here, we found that knockdown of ARNT in cancer cells reduced the proliferation rate and the transformation ability of those cells. Moreover, cisplatin-induced cell apoptosis was enhanced in ARNT-deficient cells. Expression of ARNT also decreased in the presence of cisplatin through proteasomal degradation pathway. However, ARNT level was maintained in cisplatin-treated drug-resistant cells, which prevented cell from apoptosis. Interestingly, reactive oxygen species (ROS) dramatically increased when ARNT was knocked down in cancer cells, enhancing cisplatin-induced apoptosis. ROS promoted cell death was inhibited in cells treated with the ROS scavenger, N-acetyl-cysteine (NAC).

Conclusions/Significance

These results suggested that the anticancer activity of cisplatin is attributable to its induction of the production of ROS by ARNT degradation. Targeting ARNT could be a potential strategy to eliminate drug resistance in cancer cells.

Toward discovering new anti-cancer agents targeting topoisomerase IIα: a facile screening strategy adaptable to high throughput platform

Topoisomerases are a family of vital enzymes capable of resolving topological problems in DNA during various genetic processes. Topoisomerase poisons, blocking reunion of cleaved DNA strands and stabilizing enzyme-mediated DNA cleavage complex, are clinically important antineoplastic and anti-microbial agents. However, the rapid rise of drug resistance that impedes the therapeutic efficacy of these life-saving drugs makes the discovering of new lead compounds ever more urgent. We report here a facile high throughput screening system for agents targeting human topoisomerase IIα (Top2α). The assay is based on the measurement of fluorescence anisotropy of a 29 bp fluorophore-labeled oligonucleotide duplex. Since drug-stabilized Top2α-bound DNA has a higher anisotropy compared with free DNA, this assay can work if one can use a dissociating agent to specifically disrupt the enzyme/DNA binary complexes but not the drug-stabilized ternary complexes. Here we demonstrate that NaClO₄, a chaotropic agent, serves a critical role in our screening method to differentiate the drug-stabilized enzyme/DNA complexes from those that are not. With this strategy we screened a chemical library of 100,000 compounds and obtained 54 positive hits. We characterized three of them on this list and demonstrated their effects on the Top2α–mediated reactions. Our results suggest that this new screening strategy can be useful in discovering additional candidates of anti-cancer agents.

Multi-step magnetization of the Ising model on a Shastry-Sutherland lattice: a Monte Carlo simulation

The magnetization behaviors and spin configurations of the classical Ising model on a Shastry-Sutherland lattice are investigated using Monte Carlo simulations, in order to understand the fascinating magnetization plateaus observed in TmB(4) and other rare-earth tetraborides. The simulations reproduce the 1/2 magnetization plateau by taking into account the dipole-dipole interaction. In addition, a narrow 2/3 magnetization step at low temperature is predicted in our simulation. The multi-step magnetization can be understood as the consequence of the competitions among the spin-exchange interaction, the dipole-dipole interaction, and the static magnetic energy.

Solvothermal synthesis of zincblende and wurtzite CuInS2 nanocrystals and their photovoltaic application

We report a simple solvothermal synthesis approach to the growth of CuInS(2) nanocrystals with zincblende- and wurtzite-phase structures. Zincblende nanocrystals with particle sizes of 10-20 nm were produced using oleylamine as the solvent. When ethylenediamine was used as the solvent, similarly sized wurtzite nanocrystals with some degree of particle aggregation were formed. Use of a mixture of these solvents gave products with mixed phases including some polyhedral nanostructures. The crystal phases of these nanocrystals were carefully determined by X-ray diffraction and transmission electron microscopy analysis. All the samples exhibit strong absorption from the entire visible light region to the near-infrared region beyond 1300 nm. Pure-phase zincblende and wurtzite CuInS(2) nanocrystals were employed as ink in the fabrication of solar cells. The spray-coated nanocrystal layer was subjected to a selenization process. A power conversion efficiency of ~0.74% and a good external quantum efficiency profile over broad wavelengths have been measured. The results demonstrate that wurtzite and zincblende CuInS(2) nanocrystals may be attractive precursors to light-absorbing materials for making efficient photovoltaic devices.

Bonding temperature optimization and property evolution of SU-8 material in metal/adhesive hybrid wafer bonding

Bonding temperature optimization of SU-8 material for metal/adhesive hybrid bonding was investigated. The good bond quality of SU-8 adhesive can be achieved with the bonding temperature between 150 degrees C and 250 degrees C, while bond failures of SU-8 wafers are observed starting from 275 degrees C. IR transmittance spectra measurements indicate the crosslinks inside SU-8 break and further bond failure is observed due to the large decomposition of epoxy rings and phenyl in plane bending above 275 degrees C. This research provides guidelines of material selection and bonding parameters for heterogeneous integration, 3DIC and MEMS applications using metal/adhesive hybrid bonding.

Hybrid Q-switched Yb-doped fiber laser

We investigate the performance of a hybrid Q-switched (HQS) fiber laser that is constructed with a low RF-power driven acousto-optic (AO) Q-switch and an AlGaInAs semiconductor saturable absorber. Compared to a pure passively Q-switched (PQS) fiber laser, the ratio of timing jitter to pulse period can be significantly reduced from 2% to 0.3% in the regime of far above threshold. On the other hand, the prelasing effect in a pure actively Q-switched fiber laser can be considerably improved. More importantly, the maximum pulse energy of the HQS fiber laser can be increased approximately 25% in comparison with the result of the PQS fiber laser. At a pump power of 24 W, the highest pulse energy is up to 0.56 mJ with the pulse duration of 50 ns at the repetition rate of 23 kHz.

Divalent lead cations induce cyclooxygenase-2 gene expression by epidermal growth factor receptor/nuclear factor-kappa B signaling in A431carcinoma cells

Divalent lead cations (Pb²+) are toxic metal pollutants that may contribute to inflammatory diseases in people and animals. Human vascular smooth muscle cells in culture respond to low concentrations of Pb²+ ions by activating mediators of inflammation via the plasma membrane epidermal growth factor receptor (EGFR). These include cyclooxygenase-2 (COX-2) and cytosolic phospholipase A₂ as well as the hormone-like lipid compound prostaglandin E₂. To further clarify the mechanism by which Pb²+ induces such mediators of inflammation, we tested human epidermoid carcinoma cell line A431 that expresses high levels of EGFR. Reverse transcription PCR and western blots confirmed A431 cells treated with a low concentration (1 μM) of Pb²+ in the form of lead (II) nitrate increased expression of COX-2 mRNA and its encoded protein in a time-dependent manner. Promoter deletion analysis revealed the transcription factor known as nuclear factor-kappa B (NF-κB) was a necessary component of the COX-2 gene response. NF-κB inhibitor BAY 11-7082 suppressed Pb²+-induced COX-2 mRNA expression, and EGFR inhibitors AG1478 and PD153035 as well as EGFR small interfering RNA reduced the coincident nuclear translocation of NF-κB. Our findings support the hypothesis that low concentrations of Pb²+ ions incite inflammation by inducing COX-2 gene expression via the EGFR/NF-κB signal transduction pathway.

Current research of C-Sight visual prosthesis for the blind

Electrical stimulation of the optic nerve with penetrating electrode array for visual recovery had been proposed by C-Sight group. This paper presents the latest progress of various component parts of visual prosthesis, including design and testing of neural stimulator, fabrication of multi-channel flexible microelectrode array. According to the experiment data, the linearity between practical stimulator output and the setting parameters has been validated. The temporal properties of EEP evoked by optic nerve stimulation with penetrating electrodes will be introduced briefly according to in vivo electrophysiological study.

Millijoule-level Yb-doped photonic crystal fiber laser passively Q-switched with AlGaInAs quantum wells

We report on a millijoule-level Yb-doped photonic crystal fiber (PCF) laser passively Q-switched with AlGaInAs quantum wells (QWs). Three types of AlGaInAs devices with different QW numbers are fabricated to investigate the performance. With 50 groups of three AlGaInAs QWs as a saturable absorber (SA), the PCF laser generates an average power of 7.1 W with a pulse repetition rate of 6.5 kHz at a pump power of 16 W, corresponding to the pulse energy of 1.1 mJ. The maximum peak power is up to 110 kW.

Ultrashort pulse compression and delivery in a hollow-core photonic crystal fiber at 540 nm wavelength

We have fabricated a bandgap-guiding hollow-core photonic crystal fiber (PCF) capable of transmitting and compressing ultrashort pulses in the green spectral region around 532 nm. When propagating subpicosecond pulses through 1 m of this fiber, we have observed soliton-effect temporal compression by up to a factor of 3 to around 100 fs. This reduces the wavelength at which soliton effects have been observed in hollow-core PCF by over 200 nm. We have used the pulses delivered at the output of the fiber to machine micrometer-scale features in copper.

Passively Q-switched photonic crystal fiber laser and intracavity optical parametric oscillator

We report on a passively Q-switched photonic crystal fiber (PCF) laser with Cr(4+):YAG as a saturable absorber. Under a pump power of 14.2 W, the maximum pulse energy is up to 630 microJ with a pulse width of 36 ns at a repetition rate of 5.6 kHz. With an intracavity optical parametric oscillator, the passively Q-switched PCF laser is used to generate the signal wave at 1515 nm. The output pulse energy of the signal wave is found to be 140 microJ with a pulse width as short as 1.0 ns at a repetition rate of 3.3 kHz. The very short pulse width leads to the peak power up to 140 kW.

Abstract LB-19: Involvement of aryl hydrocarbon receptor nuclear translocator in EGF-induced c-Jun/Sp1-mediated gene expression

Aryl hydrocarbon receptor nuclear translocator (ARNT)/ hydroxia-inducible factor-1β (HIF-1β) is a basic helix-loop-helix Per/AhR/ARNT/Sim (bHLH-PAS) that forms dimeric transcriptional regulatory complexes with other bHLH-PAS proteins to regulate various biological pathways. Our previous report has shown that ARNT is also involved in epidermal growth factor (EGF)-induced COX-2 gene expression. By using pull-down and protein-DNA interaction assays, we herein report that ARNT is associated with transcription factors c-Jun/Sp1, and it regulates gene expression. We find that EGF stimulated the formation of the c-Jun/ARNT/Sp1 complex and the binding of the transcription protein complex to the Sp1 site of the gene promoter in a time-dependent manner. In addition, the promoter activity and the mRNA level of 12(S)-lipoxygenase upon EGF stimulation were inhibited by ARNT small interfering RNA (siRNA). Notably, ARNT cooperated with c-Jun to regulate gene expression. Although both c-Jun and ARNT have a transactivation domain, c-Jun was responsible for the EGF-induced transcriptional activation because a dominant negative c-Jun mutant, TAM-67, blocked ARNT-mediated 12(S) lipoxygenase expression, but not the binding of ARNT to the promoter. ARNT knockdown attenuated the association between c-Jun and Sp1 and the downregulation of gene expression. Furthermore, ARNT siRNA also inhibited other EGF-induced c-Jun/Sp1 mediated gene expression, such as p21WAF1/CIP1. Our results revealed a novel mechanism by which ARNT acts as a modulator to bridge the c-Jun/Sp1 interaction and plays a role in EGF-mediated gene expression under normoxic conditions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-19.

High-power, diode-end-pumped, multigigahertz self-mode-locked Nd:YVO4 laser at 1342 nm

We report on a high-power, diode-pumped, self-mode-locked laser at 1342 nm with the Kerr effect arising from large third-order nonlinearity of Nd:YVO(4) crystal. At the pump power of 10.2 W, the average output power of 1.2 W was generated with a repetition rate in the range of 2-6 GHz. The mode-locked pulse width can be smoothly varied from 11.5 to 37 ps by controlling the amount of spatial hole burning.

Comparative studies for Cr4+:YAG crystal and AlGaInAs semiconductor used as a saturable absorber in Q-switched Yb-doped fiber lasers

We demonstrate comparative studies for Cr(4+):YAG crystal and AlGaInAs quantum-well (QW) used as a saturable absorbers in passively Q-switched Yb-doped fiber lasers. Both saturable absorbers were designed to be possessed of nearly the same initial transmission. Under a pump power of 24 W, the average output powers were up to 14.4 W and 13.8 W obtained with the AlGaInAs QWs and with the Cr(4+):YAG crystal, respectively. The maximum pulse energies obtained with the Cr(4+):YAG crystal and with the AlGaInAs QWs were found to be 0.35 mJ and 0.45 mJ, respectively.

High-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells as a saturable absorber

We demonstrate an efficient, high-pulse-energy, passively Q-switched Yb-doped fiber laser with AlGaInAs quantum wells (QWs) as a saturable absorber. The AlGaInAs QW material is designed to provide a large modulation change and a quite-low nonsaturable loss. At an incident pump power of 7.6 W, an average output power of 3.8 W, pulse energy of 300 microJ, pulse repetition rate of 12.5 kHz, and pulse duration of 30 ns was obtained.

Inhibiting glycogen synthase kinase-3 reduces endotoxaemic acute renal failure by down-regulating inflammation and renal cell apoptosis

BACKGROUND AND PURPOSE

Excessive inflammation and apoptosis are pathological features of endotoxaemic acute renal failure. Activation of glycogen synthase kinase-3 (GSK-3) is involved in inflammation and apoptosis. We investigated the effects of inhibiting GSK-3 on lipopolysaccharide (LPS)-induced acute renal failure, nuclear factor-kappaB (NF-kappaB), inflammation and apoptosis.

EXPERIMENTAL APPROACH

The effects of inhibiting GSK-3 with inhibitors, including lithium chloride (LiCl) and 6-bromo-indirubin-3'-oxime (BIO), on LPS-treated (15 mg x kg(-1)) C3H/HeN mice (LiCl, 40 mg x kg(-1) and BIO, 2 mg x kg(-1)) and LPS-treated (1 microg x mL(-1)) renal epithelial cells (LiCl, 20 mM and BIO, 5 microM) were studied. Mouse survival was monitored and renal function was analysed by histological and serological examination. Cytokine and chemokine production, and cell apoptosis were measured by enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling staining, respectively. Activation of NF-kappaB and GSK-3 was determined by immunostaining and Western blotting, respectively.

KEY RESULTS

Mice treated with GSK-3 inhibitors showed decreased mortality, renal tubular dilatation, vacuolization and sloughing, blood urea nitrogen, creatinine and renal cell apoptosis in response to endotoxaemia. Inhibiting GSK-3 reduced LPS-induced tumour necrosis factor-alpha (TNF-alpha) and CCL5/RANTES (released upon activation of normal T-cells) in vivo in mice and in vitro in murine kidney cortical collecting duct epithelial M1 cells. Inhibiting GSK-3 did not block TNF-alpha-induced cytotoxicity in rat kidney proximal tubular epithelial NRK52E or in M1 cells.

CONCLUSIONS AND IMPLICATIONS

These results suggest that GSK-3 inhibition protects against endotoxaemic acute renal failure mainly by down-regulating pro-inflammatory TNF-alpha and RANTES.

Beta-catenin expression and mutation in adult and pediatric Wilms' tumors

Wilms' tumor is the most common pediatric renal neoplasm, but its occurrence in adults is very rare. In contrast to pediatric Wilms' tumor (PWT), very little is known about the pathogenesis of adult Wilms' tumor (AWT). Despite there currently being no morphological difference between AWT and PWT, a cytogenetic study has suggested that the pathogenesis of AWT might be different from that of PWT. Although dysregulation of the Wnt pathway has been implicated in PWT, its role in AWT has never been investigated. To investigate the role of dysregulation of the Wnt pathway in AWT, tumor samples from 4 AWTs and 19 PWTs were surveyed for subcellular localization of beta-catenin by immunohistochemistry and potential mutation of the beta-catenin gene by sequencing. Nuclear translocation of beta-catenin was found in one out of four cases of AWT, but none of them carried mutation of the beta-catenin gene. By comparison, nuclear translocation for beta-catenin and mutation of the beta-catenin gene were present in 53% (10/19) and 15.8% (3/19) of PWTs, respectively. Of the three mutations identified, we found a novel mutation combining a silent mutation (TCT to TCC, Ser37Ser) and an in-frame six-base-pair deletion (del GGTGCC, del Gly38Ala39). This report suggests that dysregulation of the Wnt pathway might also play a role in the pathogenesis of AWT.

Extracellular acidification elicits spatially and temporally distinct Ca2+ signals

Extracellular acidification accompanies neoplastic transformation of tissues and increases with tumor aggressiveness [1, 2]. The intracellular signaling cascade triggered by this process remains poorly understood and may be linked to recently discovered proton-activated G protein-coupled receptors such as OGR1 and G2A [3, 4]. Here, we report that OGR1 and G2A are expressed in human medulloblastoma tissue and its corresponding neuronal cell line. We show that extracellular acidification activates phospholipase C, IP(3) formation, and subsequent Ca2+ release from thapsigargin-sensitive stores in neurons. The number of responsive cells and the amount of Ca2+ released from stores correlated positively with the extent of extracellular acidification. Ca2+ release recruited the MEK/ERK pathway, providing a mechanistic explanation for how acidification stimulates cell growth. In addition, acidification activated Ca2+-permeable ion channels through a mechanism dependent on phospholipase C but independent of store depletion or a cytoplasmic Ca2+ rise. Hence, extracellular acidification, to levels seen in tumor tissue, activates temporally and spatially distinct pathways that elevate Ca2+ and may be directly relevant for tumor cell biology.

Primary mediastinal large B-cell lymphoma mimicking liposarcoma

A 78-year-old man consulted for acute exacerbation of chronic obstructive pulmonary disease (COPD) and an incidental finding of an anterior mediastinal tumor on chest radiograph was noted on admission. Chest computed tomography (CT) revealed a fat-containing mediastinal mass with solid component. Mediastinal liposarcoma was the initial diagnosis based on image characteristics but histopathologic examination of the excised tumor revealed lymphoma infiltration of the mediastinal adipose tissue. To our knowledge, this is the first case report of lymphomatous growth in mediastinal lipomatosis.

Superoxide anion-dependent Raf/MEK/ERK activation by peroxisome proliferator activated receptor gamma agonists 15-deoxy-delta(12,14)-prostaglandin J(2), ciglitazone, and GW1929

In this study, we examined the signaling pathways for extracellular signal-related protein kinase (ERK) activation by three structurally different peroxisome proliferator activated receptor-gamma (PPARgamma) agonists. In murine C2C12 myoblasts, treatment with 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), ciglitazone, and GW1929 leads to ERK1/2 phosphorylation in a time- and concentration-dependent manner. Consistent with ERK phosphorylation, mitogen activated protein/ERK kinase (MEK) phosphorylation as well as Raf-1 kinase activity are also accordingly stimulated, while the constitutive Ser259 phosphorylation of Raf-1 is decreased. The ERK phosphorylation induced by PPARgamma agonists is not blocked by the PKC inhibitors GF109203X and Ro31-8220, the PI3K inhibitor wortmannin, the Ras inhibitor FPTI, the negative mutant of Ras, or the PPARgamma antagonist bisphenol A diglycidil ether. Expression of PPARgamma2 without DNA binding domain or with a nonphosphorylatable mutant (S112A) fails to change ERK phosphorylation by 15d-PGJ(2). On the contrary, the ERK phosphorylation by PPARgamma agonists is inhibited by the MEK inhibitor PD98059, GSH, and permeable SOD mimetic MnTBAP. Chemiluminescence study reveals that these three PPARgamma agonists are able to induce superoxide anion production, with an efficacy similar to their action on ERK phosphorylation. Consistent with this notion, we also show that superoxide anion donor 2,3-dimethoxy-1,4-naphoquinone elicits ERK phosphorylation. In this study, we for the first time demonstrate a novel mechanism, independent of Ras activation but initiated by superoxide anion production, for PPARgamma agonists to trigger the Raf-MEK-ERK1/2 signaling pathway.

Automated nasopharyngeal carcinoma detection with dynamic gadolinium-enhanced MR imaging

OBJECTIVES

The purpose of this research is to develop an automatic medical diagnosis for segmenting nasopharyngeal carcinoma (NPC) with dynamic gadolinium-enhanced MR imaging.

METHODS

This system is a multistage process, involving motion correction, head mask generation, dynamic MR data quantitative evaluation, rough segmentation, and rough segmentation refinement. Two approaches, a relative signal increase method and a slope method, are proposed for the quantitative evaluation of dynamic MR data.

RESULTS

The NPC detection results obtained using the proposed methods had a rating of 85% in match percent compared with these lesions identified by an experienced radiologist. The match percent for the two proposed methods did not have significant differences. However, the computation cost for the slope method was about twelve times faster than the relative signal increase method.

CONCLUSIONS

The proposed methods can identify the NPC regions quickly and effectively. This system can enhance the performance of clinical diagnosis.

Protein kinase C and changes in manganese superoxide dismutase gene expression in cultured glial cells

1. To study the role of protein kinase C (PKC) in the increase in manganese superoxide dismutase (Mn-SOD) gene expression following transient hypoxia in glial cells, we examined the mRNA levels of Mn-SOD using northern blot analysis. 2. The Mn-SOD mRNA levels were markedly increased after exposure to nitrogen gas for 5 min. 3. Pretreatment with chelerythrine or GF109203x, inhibitors of PKC, attenuated the increase in Mn-SOD mRNA following hypoxia in a concentration-dependent manner. 4. Incubation with phorbol 12-myristate 13-acetate, the PKC activator, enhanced the increase in Mn-SOD gene expression in response to transient hypoxia. 5. The results suggest that hypoxia increases Mn-SOD gene expression in cultured glial cells mainly through activation of a PKC pathway.