Deletion of the cardiolipin-specific phospholipase Cld1 rescues growth and life span defects in the tafazzin mutant: implications for Barth syndrome

Cardiolipin (CL) that is synthesized de novo is deacylated to monolysocardiolipin (MLCL), which is reacylated by tafazzin. Remodeled CL contains mostly unsaturated fatty acids. In eukaryotes, loss of tafazzin leads to growth and respiration defects, and in humans, this results in the life-threatening disorder Barth syndrome. Tafazzin deficiency causes a decrease in the CL/MLCL ratio and decreased unsaturated CL species. Which of these biochemical outcomes contributes to the physiological defects is not known. Yeast cells have a single CL-specific phospholipase, Cld1, that can be exploited to distinguish between these outcomes. The cld1Δ mutant has decreased unsaturated CL, but the CL/MLCL ratio is similar to that of wild type cells. We show that cld1Δ rescues growth, life span, and respiratory defects of the taz1Δ mutant. This suggests that defective growth and respiration in tafazzin-deficient cells are caused by the decreased CL/MLCL ratio and not by a deficiency in unsaturated CL. CLD1 expression is increased during respiratory growth and regulated by the heme activator protein transcriptional activation complex. Overexpression of CLD1 leads to decreased mitochondrial respiration and growth and instability of mitochondrial DNA. However, ATP concentrations are maintained by increasing glycolysis. We conclude that transcriptional regulation of Cld1-mediated deacylation of CL influences energy metabolism by modulating the relative contribution of glycolysis and respiration.

Activation of the JAK-STAT3 pathway is associated with the growth of colorectal carcinoma cells

Excessive activation of inflammatory signaling pathways facilitates colorectal carcinoma (CRC) malignancy. Continuous activation of the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway plays a central role in the development and progression of CRC. With the intent to explore whether attenuation of the JAK-STAT3 signaling axis inhibits cancer cell proliferation or induces apoptosis, a sophisticated oncolytic adenoviral vector, AdCN305, carrying the SOCS3 gene was used to treat CRC cells. Our data revealed that i) in CRC cells, STAT3 was continuously activated by phosphorylation, and SOCS3 was at a relative low expression level; and ii) AdCN305-cppSOCS3 inhibited the continuous activation of the JAK/STAT3 pathway, suppressed CRC cell growth and induced apoptosis, in vitro and in vivo. We proved that SOCS3, a negative regulator of the JAK-STAT3 pathway, efficiently inhibited the activation of the pathway and decreased levels of downstream factors which regulate cell proliferation and the cell cycle.

The effect of dornase alfa on ventilation inhomogeneity in patients with cystic fibrosis

Outcome measures to assess therapeutic interventions in cystic fibrosis (CF) patients with mild lung disease are lacking. Our aim was to determine if the lung clearance index (LCI) can detect a treatment response to dornase alfa in paediatric CF patients with normal spirometry. CF patients between 6-18 yrs of age with FEV(1 )≥ 80% pred were eligible. In a crossover design, 17 patients received 4 weeks of dornase alfa and placebo in a randomised sequence separated by a 4-week washout period. The primary end-point was the change in LCI from dornase alfa versus placebo. A mixed model approach incorporating period-dependent baselines was used. The mean ± sd age was 10.32 ± 3.35 yrs. Dornase alfa improved LCI versus placebo (0.90 ± 1.44; p = 0.022). Forced expiratory flow at 25-75% expired volume measured by % pred and z-scores also improved in subjects on dornase alfa (6.1% ± 10.34%; p = 0.03 and 0.28 ± 0.46 z-score; p = 0.03). Dornase alfa significantly improved LCI. Therefore the LCI may be a suitable tool to assess early intervention strategies in this patient population.

Potent antitumor activity in experimental hepatocellular carcinoma by adenovirus-mediated coexpression of TRAIL and shRNA against COX-2

PURPOSE

Recent studies have indicated that short hairpin RNA (shRNA) driven by RNA polymerase (Pol) II promoters can be transcribed into precursor mRNAs together with transgenes. It remains unclear, however, whether coexpression of shRNA and transgene from a single promoter is feasible for cancer therapy.

EXPERIMENTAL DESIGN

In this study, we generated novel adenoviral vectors that permitted coexpression of shRNA against cyclooxygenase-2 (COX-2) and the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) therapeutic gene from a cytomegalovirus promoter to evaluate whether silencing of COX-2 could increase the sensitivity of hepatocellular carcinoma to TRAIL.

RESULTS

Our data showed that adenovirus vector Ad-TM, in which the shRNA was inserted into the 3' untranslated region of the TRAIL gene, not only significantly suppressed COX-2 expression, but also expressed a high level of TRAIL. Moreover, infection with Ad-TM resulted in significant cytotoxicity in hepatocellular carcinoma cell lines. In contrast, it had no effect on normal liver cell line. Impressively, treatment of the established hepatocellular carcinoma tumors with Ad-TM resulted in complete tumor regression. This potent antitumor activity induced by Ad-TM was due to strong inhibition of COX-2 and high expression of TRAIL. Furthermore, using the shRNA and transgene coexpression adenovirus system, we showed that silencing of COX-2 increased the sensitivity of hepatocellular carcinoma to TRAIL through inhibition of Bcl-2 and Bcl-w.

CONCLUSION

This study indicated that adenovirus carrying shRNA and transgene expressed from a single promoter represented a potent approach for cancer therapy.

Carotid atherosclerosis and a reduced likelihood for lowered cognitive performance in a Canadian First Nations population

BACKGROUND

We investigated the associations among cardiovascular risk factors, carotid atherosclerosis and cognitive function in a Canadian First Nations population.

METHODS

Individuals aged > or = 18 years, without stroke, nonpregnant and with First Nations status were assessed by the Trail Making Test Parts A and B. Results were combined into a Trail Making Test executive function score (TMT-exec). Doppler ultrasonography assessed carotid stenosis and plaque volume. Anthropometric, vascular and metabolic risk factors were assessed by interview, clinical examinations and blood tests.

RESULTS

For 190 individuals with TMT-exec scores, the median age of the population was 39 years. Compared to the reference group, individuals with elevated levels of left carotid stenosis (LCS) and total carotid stenosis (TCS) were less likely to demonstrate lowered cognitive performance [LCS, odds ratio (OR): 0.47, 95% confidence interval (CI): 0.24-0.96; TCS, OR: 0.40, 95% CI: 0.20-0.80]. No effect was shown for plaque volume. In structural equation modeling, we found that for every 1-unit change in the anthropometric factor in kg/m(2), there was a 0.86-fold decrease in the percent of TCS (p < 0.05).

CONCLUSIONS

Individuals with elevated levels of LCS and TCS were less likely to demonstrate lowered performance. There was some suggestion that TCS mediates the effect of anthropometric risk factors on cognitive function.

Therapeutic vaccination against advanced pancreatic cancer by autologous dendritic cells pulsed with a MUC1 peptide: Preclinical results of a clinical phase I trial

e15652

Background: Pancreatic ductal adenocarcinoma has a particularly poor prognosis. Therefore, novel therapeutic strategies such as immunotherapy are required. The aim of the present phase I study was to evaluate the safety, immune responses and clinical activity of a vaccine based on autologous dendritic cells (DC) pulsed with a specific MUC1 peptide in advanced pancreatic cancer patients. Methods: Five patients who had pancreatic cancer ductal adenocarcinoma expressing MUC1 in stage of III/IV were enrolled to the clinical trial. Patients underwent leukapheresis to generate dendritic cells by culture in vitro with granulocyte macrophage colony-stimulating factor and interleukin-4 for 5 days. Dendritic cells were then pulsed overnight with MUC1 peptide (GVTSAPDTRPAPGSTAPPAH) and harvested for vaccination. Dendritic cells (3×106-6×106) were injected intradermally every 2 weeks for 3–4 times. Results: All patients remained with progressive disease. Four patients developed strong T-cell IFN-γ and Granzyme B Elispot responses to the vaccine. Most interestingly, the patient who was treated with the highest number of DC(6×106) had more number of CTL than other patients and showed delayed-type hypersensitivity responses at injection sites and this patient stopped application of the analgetics. Another patient with relapsed pancreatic cancer who had finished the 4 times of vaccination and then followed 6 times of chemotherapy with Gemcitabine had a surprisingly long term of survival of 12 month. No evidence of significant treatment related toxicity or auto-immunity was observed. Conclusions: This study showed the safety and clinical response of MUC1 peptide-pulsed dendritic cell therapy for patients with advanced pancreatic cancer. It confirms the capability of this DC vaccine to stimulate an immune response in patients with pancreatic cancer even in the presence of a large tumor burden. Dendritic cell therapy is recommended for further clinical studies in pancreatic cancer patients.

No significant financial relationships to disclose.

A novel recombinant tandem repeat DNA vaccine targeting at MUC1

3066

Background: Tandem repeat (TR) is the key epitope of mucin 1 (MUC1) for inducing cytotoxic T lymphocytes (CTL) to kill the tumor cells specifically. A novel recombinant TR DNA vaccine was constructed to study its induced immune responses. Methods: A recombinant human TR (rhTR) gene encoding a single TR polypeptide of MUC1 was synthesized and cloned into the multiple cloning sites of plasmid pcDNA3.1/Myc-his (+) A to construct the recombinant plasmid pcDNA3.1-TR/Myc-his (+) A (pTR plasmid). Expression of pTR plasmid was confirmed by transfection assay and Western blot analysis. C57BL/6 (H-2b) mice were immunized with pTR plasmid (n=15) by tibial muscle injection. Mice inoculated with the empty vector (EV group, n=15) and 0.9% NaCl solution (NS group, n=15) were used as vector and blank control respectively. Four weeks later, all mice were immunized again. Specific antibody detection and cytotoxic assay were used to evaluate the vaccine-induced TR specific immune responses. Results: DNA sequencing confirmed that the pTR plasmid was exactly constructed. Transfection assay and Western blot analysis found that the transfected COS7 cells expressed TR polypeptide of MUC1 48 hours after transfection. Cytotoxic assay showed that immunization with pTR plasmid into C57BL/6 mice resulted in more efficient induction of CTL specific cytolysis against TR polypeptide than that of EV group and NS group (p<0.01). Vaccine immunized mice had a higher equivalent concentration of anti-TR specific antibodies (2324μg/ml±238μg/ml) than that of EV group (1896μg/ml±533μg/ml, p<0.01) and NS group (1736μg/ml±142μg/ml, p<0.01). Conclusions: The novel recombinant TR DNA vaccine targeting at MUC1 was exactly constructed, immunization with which could induce TR specific CTL response and antibodies response in mice.

No significant financial relationships to disclose.

[Studies on the feasibility of detecting circulating antibodies in saliva of Schistosoma japonicum infected rabbits]

AIM

To investigate the feasibility of detecting anti-Schistosoma japonicum antibodies in saliva.

METHODS

Saliva and serum samples of 5 infected, 7 reinfected and 8 treated rabbits were collected at different times periods. The CAb in saliva and serum was detected by using ELISA.

RESULTS

The sensitivity of ELISA was 94.7% for saliva and 100% for serum. The specificity of ELISA was 100% for both saliva and serum.

CONCLUSION

Saliva can be used to detect circulating antibodies for the diagnosis of schistosomiasis japonica.

[Preparation of monoclonal antibodies by intrasplenic immunization of mice with urine circulating antigen from patients infected with Schistosoma japonicum]

AIM

To explore an efficient method for preparing monoclonal antibodies against circulating antigen of S. japonicum in the urine of schistosomiasis patients.

METHODS

The urine of schistosomasis patients were precipitated with 5% trichloroacetic acid, and then used to immunize the BALB/c mice by intrasplenic immunization to prepare McAb.

RESULTS

Two monoclonal cell lines against the CAg in the urine of schistosomiasis patients have been established. The immunoglobulin subclass of the 2 McAbs (2E6 and 2B11) were identified as IgM. The titres of 2E6 and 2B11 were 2.56 x 10(5) and 6.4 x 10(4). On immunodiffusion, McAb 2E6 showed one precipitation line with IHU-CAg, however, both McAbs did not react with NHU-CAg. Using ascitic fluid of 2B11 and 2E6 as capture antibody separately, and HRP-H11 as labelled antibody to detect the urine of 12 acute schistosomasis patients, 2B11 2E6 gave 6 and 3 positive, respectively, whereas 8 normal urine were all negative.

CONCLUSION

It is feasible to use CAg from schistosomasis patients' urine to prepare anti-CAg McAb by intrasplenic immunization in mice.

[Determination of circulating antigen in urine of rabbits infected with Schistosoma japonicum]

AIM

To develop an immunoassay for the detection of circulating schistosome antigen (CSA) in host urine.

METHODS

CSA extracted from the urine of the rabbits infected with Schistosoma japonicum was used for preparing and selecting specific monoclonal antibody. A one-step dot-ELISA using this specific McAb and a 2nd antibody was used for detection of circulating schistosome antigen in the urine of infected rabbits.

RESULTS

No CSA was detected in urine from all of 22 rabbits before infection. The positive rate of CSA in infected rabbits was correlated with the intensity of infection and the time of infection. No CSA was detected in the urine rabbits of 3 weeks after infection with 25 cercariae while the positive rate of CSA in the urine from rabbits infected with 200 cercariae was 40% and 100% after 3 and 6 weeks, respectively. A combination of CSA detection in both urine and serum may increase the detectability.

CONCLUSION

The specific McAb prepared by urine CSA of Schistosoma japonicum-infected rabbits can be used as a probe for detecting CSA in the urine of infected rabbits.

[Establishment and application of dipstick sandwich colloidal dye immunoassay for circulating antigen detection in schistosomiasis patients]

AIM

To set up a simple immunoassay for the detection of circulating antigens in host serum.

METHODS

A kind of colloidal pale purple dye (HFRL) used as a staining reagent for immunoassay was first selected from the dyes produced in China and an optimum condition for labelling the dye onto the combined IgM antibodies was explored. A dipstick sandwich colloidal dye immunoassay (DS-DIA) for the detection of circulating antigens in host sera was established.

RESULTS

The minimal concentration of SEA detected was 5 ng/ml by DS-DIA. Serum circulating antigen detection in 14 cases of acute schistosomiasis japonica, 113 chronic cases and in 113 healthy controls revealed that the sensitivity was 100% in acute cases, 52.2% in chronic cases and the specificity was 92.9% for uninfected students. The sensitivity and specificity of DIA were similar to those of dot-ELISA. A certain degree of diagnostic complementarity up to 76.1% in sera from these patients was seen when DS-DIA and dot-ELISA were used in paralle.

CONCLUSION

DS-DIA is a simple, economical and reliable method for detecting circulating antigens of Schistosoma japonicum, having a wide potential value especially for field use.

[Comparative observation on the efficacy of several test/probe systems for detecting schistosome circulating antigen]

AIM

To compare the efficacy of 5 test/probe systems for the detecting of schistosomal circulation antigen (SCA) in sera from infected rabbits.

METHODS

Nine rabbits were infected with monosexual cercariae (either male or female), 7 rabbits were infected with bisexual cercariae as controls. Blood samples were collected periodically post infection (p.i). 15 rabbits were infected each with 250 bisexual cercaria and divided into 3 groups, 2 groups were treated with allyl thiourea (295-590 mg/kg) from 19 d or 46 d respectively, to inhibit their egg formation. One untreated group was used as control. Blood samples were collected weekly until 8 wk post infection. SCA detecting methods include (1) dot-ELISA/McAb anti-surface membrane antigen of adult worms (8SE4), (2) dot-ELISA/McAb anti-CCA (3D10), (3) Sandwich dot-ELISA/McAb anti-egg antigen (MG2), (4) Sandwich-ELISA/McAb anti-egg antigen (2H10), (5) Sandwich-ELISA/McAb anti-CAA (1B10).

RESULTS

Using method (1) all of the 18 rabbits infected with monosexual cercariae were negative. Using method (2) only 1 rabbit harboured 133 male worms showed positive. Using method (5) no SCA were detected in sera from female cercariae-infected rabbits but 3 out of 9 male cercariae-infected rabbits showed positive reaction. SCA detecting results from rabbits treated with allyl thiourea: both method (1) and (3) showed negative in rabbits treated from 19 d (p.i.) but all gave positive reaction in 6-7 wk in rabbits treated from 46 d (p.i.). There were all negative detected by using method (4) and all positive at 6 wk (p.i.) detected by method (5) in rabbits of 3 groups whether treated or non-treated.

CONCLUSION

Various test/probe systems have different efficacy in detecting SCA but (5) of the methods (1)(2) tests/probe systems could not detect SCA in rabbits with single female cercariae infection. From the egg formation inhibition study, the SCA detected by McAb 8SE4 dot-ELISA might be related to egg maturation. Whether the surface membrane antigen of adult worm has common antigenic component with egg antigen remains to be studied.

Artificial neural network-based predictive model for bacterial growth in a simulated medium of modified-atmosphere-packed cooked meat products

The data of Devilieghere et al. (Int. J. Food Microbiol. 1999, 46, 57--70) on bacterial growth in a simulated medium of modified-atmosphere-packed cooked meat products was processed for estimating maximum specific growth rate mu(max) and lag phase lambda of Lactobacillus sake using artificial neural networks-based model (ANNM) computation. The comparison between ANNM and response surface methodology (RSM) model showed that the accuracy of ANNM prediction was higher than that of RSM. Two-dimensional and three-dimensional plots of the response surfaces revealed that the relationships of water activity a(w), temperature T, and dissolved CO(2) concentration with mu(max) and lambda were complicated, not just linear or second-order relations. Furthermore, it was possible to compute the sensitivity of the model outputs against each input parameter by using ANNM. The results showed that mu(max) was most sensitive to a(w), T, and dissolved CO(2) in this order; whereas lambda was sensitive to T the most, followed by a(w), and dissolved CO(2) concentrations.

[Study on the relation between the cell cycle regulators and laryngeal carcinogenesis]

OBJECTIVE

To investigate the clinicopathological significance of the Cyclin E, p21WAF1/CIP1 and p53 expression in laryngeal carcinogenesis.

METHOD

The expression of Cyclin E, p21WAF1/CIP1 and p53 was examined by using immunohistochemical method in normal epithelia (20), dysplastic epithelia (40) and laryngeal cancers (60).

RESULT

1. In normal epithelium, dysplastic squamous epithelium and in squamous cell carcinoma of the larynx, the positive immunostaining rate of Cyclin E protein was 5.0%(1/20), 20.0%(8/40) and 45.0%(27/60) respectively (P < 0.001), and p21WAF1/CIP1 protein was 95.0%(19/20), 75.0%(30/40) and 63.3%(38/60) respectively (P < 0.01), while the rate of p53 was 0, 30.0%(12/40) and 61.7%(37/60)(P < 0.001) respectively. 2. p21WAF1/CIP1 positive expression in highly, moderately and poorly differentiated carcinomas were 76.2%(16/21), 66.5%(19/29) and 30.0%(3/10) respectively (P < 0.05), p21WAF1/CIP1 protein expression was significantly associated with tumour cell differentiation. 3. The positive expression of Cyclin E closely related with the positive expression of p53 (P < 0.05). No correlation was found between p21WAF1/CIP1 expression and p53 expression.

CONCLUSION

1. Cyclin E and p53 could be an early molecular event in the carcinogenesis of larynx. 2. p21WAF1/CIP1 expression is associated with tumour cell differentiation. 3. The mutual mechanism of cell cycle regulators (Cyclin E, p21WAF1/CIP1 and p53) play an important role in the laryngeal carcinoma.

Physician-patient discussions of controversial cancer screening tests

BACKGROUND

Screening mammography for younger women and prostate-specific antigen (PSA) measurement have controversial benefits and known potential adverse consequences. While providing informed consent and eliciting patient preference have been advocated for these tests, little is known about how often these discussions take place or about barriers to these discussions.

METHODS

We administered a survey to medical house staff and attending physicians practicing primary care. The survey examined physicians' likelihood of discussing screening mammography and PSA testing, and factors influencing the frequency and quality of these discussions.

RESULTS

For the three scenarios, 16% to 34% of physicians stated that they do not discuss the screening tests. The likelihood of having a discussion was significantly associated with house staff physicians' belief that PSA screening is advantageous; house staff and attending physicians' intention to order a PSA test, and attending physicians' intention to order a mammogram; and a controversial indication for screening. The most commonly identified barriers to discussions were lack of time, the complexity of the topic, and a language barrier.

CONCLUSIONS

Physicians report they often do not discuss cancer screening tests with their patients. Our finding that physicians' beliefs and intention to order the tests, and extraneous factors such as time constraints and a language barrier, are associated with discussions indicates that some patients may be inappropriately denied the opportunity to choose whether to screen for breast and prostate cancer.

Phospholipase C is involved in kinetochore function in Saccharomyces cerevisiae

The budding yeast PLC1 gene encodes a homolog of the delta isoform of mammalian phosphoinositide-specific phospholipase C. Here, we present evidence that Plc1p associates with the kinetochore complex CBF3. This association is mediated through interactions with two established kinetochore proteins, Ndc10p and Cep3p. We show by chromatin immunoprecipitation experiments that Plc1p resides at centromeric loci in vivo. Deletion of PLC1, as well as plc1 mutations which abrogate the interaction of Plc1p with the CBF3 complex, results in a higher frequency of minichromosome loss, nocodazole sensitivity, and mitotic delay. Overexpression of Ndc10p suppresses the nocodazole sensitivity of plc1 mutants, implying that the association of Plc1p with CBF3 is important for optimal kinetochore function. Chromatin extracts from plc1Delta cells exhibit reduced microtubule binding to minichromosomes. These results suggest that Plc1p associates with kinetochores and regulates some aspect of kinetochore function and demonstrate an intranuclear function of phospholipase C in eukaryotic cells.