SAG/ROC2/RBX2 is a HIF-1 target gene that promotes HIF-1 alpha ubiquitination and degradation

SAG (sensitive to apoptosis gene) or ROC2/RBX2 is the second family member of ROC1/RBX1, a component of SCF (Skp1, Cullin, F-box protein) and VCB (von Hippel-Lindau (VHL), Cullin and Elongin B/C) E3 ubiquitin ligases. SAG protected cells from hypoxia-induced apoptosis when overexpressed. We report here that SAG was subjected to hypoxia induction at the levels of mRNA and protein. Hypoxia induction of SAG was largely HIF-1alpha dependent. A consensus HIF-1-binding site, GCGTG was identified in the first intron of the SAG gene. In response to hypoxia, HIF-1 bound to this site and transactivated SAG expression. SAG transactivation required both the intact binding site in cis and HIF-1alpha in trans. On the other hand, like its family member, ROC1, SAG promoted VHL-mediated HIF-1alpha ubiquitination and degradation, which was significantly inhibited upon small interfering RNA silencing of SAG or ROC1. Furthermore, the endogenous HIF-1alpha at both basal and hypoxia-induced levels was significantly increased upon SAG silencing. Finally, SAG forms in vivo complex with Cul-5 and VHL under hypoxia condition. These results suggest an HIF-1-SAG feedback loop in response to hypoxia, as follows: hypoxia induces HIF-1 to transactivate SAG. Induced SAG then promotes HIF-1alpha ubiquitination and degradation. This feedback loop may serve as a cellular defensive mechanism to reduce potential cytotoxic effects of prolonged HIF-1 activation under hypoxia.

Death on the kidney waiting list--good candidates or not?

The waiting list for a kidney or simultaneous pancreas-kidney transplant is growing, and waiting times are getting longer. As a consequence, transplant candidates are dying while waiting for a transplant. In a retrospective analysis, we studied whether patients on our list who died while waiting were good candidates. From January 1, 2002, through September 30, 2004, 85 candidates on our list died. Of these, 71% were waiting for a first transplant; 62% had a current panel-reactive antibody (PRA) level of 0%. Of the 85 candidates who died, the mean (+/-SD) age was 53 +/- 11 years; mean waiting time from listing to death, 979 +/- 749 days. The most common cause of death was cardiovascular disease. Many of those candidates who died while waiting were young, first-transplant candidates with a low PRA level. But only limited information was available; prospective studies are necessary to determine whether or not they were, in fact, good candidates.

Mobilized retrotransposon Tos17 of rice by alien DNA introgression transposes into genes and causes structural and methylation alterations of a flanking genomic region

Tos17 is a copia-like endogenous retrotransposon of rice, which can be activated by various stresses such as tissue culture and alien DNA introgression. To confirm element mobilization by introgression and to study possible structural and epigenetic effects of Tos17 insertion on its target sequences, we isolated all flanking regions of Tos17 in an introgressed rice line (Tong35) that contains minute amount of genomic DNA from wild rice (Zizania latifolia). It was found that there has been apparent but limited mobilization of Tos17 in this introgression line, as being reflected by increased but stable copy number of the element in progeny of the line. Three of the five activated copies of the element have transposed into genes. Based on sequence analysis and Southern blot hybridization with several double-enzyme digests, no structural change in Tos17 could be inferred in the introgression line. Cytosine methylation status at all seven CCGG sites within Tos17 was also identical between the introgression line and its rice parent (Matsumae)-all sites being heavily methylated. In contrast, changes in structure and cytosine methylation patterns were detected in one of the three low-copy genomic regions that flank newly transposed Tos17, and all changes are stably inherited through selfed generations.

Serial monitoring for circulating cancer cells in blood samples of stage 1–4 breast cancer patients

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Serial monitoring for presence, number & characterization of circulating cancer cells (CCC) may provide valuable information that may be relevant to prognosis and treatment outcomes of breast cancer patients (BCP). We conducted a serial blood sampling study at the University of Maryland in BCP with stage 1–4 breast carcinoma. 15–20 ml of venous blood were collected before the start of systemic therapy and periodically thereafter & processed using negative selection method with double-gradient centrifugation & magnetic cell sorting to remove WBCs. Digital images of FITC-positive epithelial cells were acquired with a fluorescence microscope & counted. CCC from 41 patients (Pts) were also stained with Trastuzu-mAb-532 to quantify the HER-2/neu cell surface receptor expression relative to a fluorescence standard. 105 Pts were accrued & 415 blood samples tested (median number of samples/pt; 4 (1–8). During the 24 mos. monitoring period CCC were detected in 57 of 105 pts (54%). The Table below shows that presence of >10 CCC/sample is associated with decreased survival and increased probability of having metastatic disease.(Exact chi-square test for presence vs. absence of metastatses in A, B, C, D groups, P < 0.0001; Fisher’s exact test to compare individual groups: for B vs C+ D, P < 0.001; B vs C, P=0.001). HER-2/neu expression was assessed in CCC of 25 pts (minimum of 4 CCC per sample) as compared with strongly HER-2/neu positive control cell line SKBR-3. 10 Pts were positive & 15 negative for HER-2/neu over-expression in CCC. CCC data & primary tumor data concurred in 6 of 7 Her-2/neu primary tumor tissue positive Pts & in 12 of 13 Her-2/neu primary tissue negative Pts. For 5 Pts tissue data was not available. Conclusions: Increasing CCC numbers/sample appear to correlate with adverse outcome of BCP. Our CCC Test may provide valuable information about prognosis of stage 1–4 BCP. HER-2/neu expression could be quantified in individual CCC & concurred with primary tumor data in 90% of Pts. Supported by NCI Grant CA081903

[Table: see text]

[Table: see text]

Gene expression profiling identifies two distinct papillary renal cell carcinoma (RCC) subgroups of contrasting prognosis

4503

Background: Despite the moderate incidence of papillary renal cell carcinoma (PRCC), there is a disproportionately limited understanding of its underlying genetic programs. There is no effective therapy for metastatic PRCC, and patients are often excluded from kidney cancer trials. A morphological classification of PRCC into Type 1 and Type 2 tumors has been recently proposed, but its biological relevance remains uncertain. Methods: We studied the gene expression profiles of 34 cases of PRCC using Affymetrix HGU133 Plus 2.0 arrays (54,675 probe sets) using both unsupervised and supervised analysis. Comparative genomic microarray analysis (CGMA) was used to infer cytogenetic aberrations, and pathways were ranked with a curated database. Expression of selected genes was validated by immunohistochemistry in 34 samples, with 15 independent tumors. Results: We identified two highly distinct molecular PRCC subclasses with morphologic correlation. The first class, with excellent survival, corresponded to three histological subtypes: Type 1, low-grade Type 2 and mixed Type 1/low-grade Type 2 tumors. The second class, with poor survival, corresponded to high-grade Type 2 tumors (n = 11). Dysregulation of G1/S and G2/M checkpoint genes were found in Class 1 and Class 2 tumors respectively, alongside characteristic chromosomal aberrations. We identified a 7-transcript predictor that classified samples on cross-validation with 97% accuracy. Immunohistochemistry confirmed high expression of cytokeratin 7 in Class 1 tumors, and of topoisomerase IIα in Class 2 tumors. Conclusions: We report two molecular subclasses of PRCC, which are biologically and clinically distinct, which may be readily distinguished in a clinical setting. This may also have therapeutic implications.

No significant financial relationships to disclose.

The von Hippel-Lindau gene mutation is associated with the good-prognosis profiling subtype of clear cell renal cell carcinoma

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Background: The prevalence of von Hippel-Lindau (VHL) mutations in clear cell renal cell carcinoma (ccRCC) is about 30–50%. The association between VHL mutation and patient prognosis remains controversial, despite extensive in vitro research on its role in hypoxia response. We have previously reported a robust prognostic classification of ccRCC using gene expression profiling. In view of reports of activity of anti-angiogenesis agents, we studied the association of VHL mutation with tumor profiling subtypes, survival and other clinical parameters. Methods: All exons of the VHL gene in 88 ccRCC samples were sequenced. Expression profiling using oligonucleotide arrays (54,675 probe sets) was also performed, and the samples classified using hierarchical clustering. For identification of VHL mutation specific signatures, nearest shrunken centroids with internal validation was used with a 10% misclassification cutoff. Results: 35% of the samples had VHL mutations. Mutation status was not significantly associated with survival on univariate analysis (p = 0.54). Hierarchical clustering yielded two ccRCC subtypes with divergent clinical outcomes (HR = 4.13, p < 0.001). VHL mutations were significantly associated with the good-prognosis profiling subtype of ccRCC tumors (OR 3.3, p = 0.04), but no effect modification between VHL mutation and the prognostic subtypes was found (p=0.31). No standard clinical parameter was associated with VHL mutation. No significant association between VHL mutation and downstream hypoxia response gene expression, including VEGF (p = 0.14), PDGF (p = 0.5), TGF-A (p = 0.24) and GLUT1 (p = 0.45) was found. Conclusion: While VHL mutation is associated with a biologically distinct good-prognosis profiling tumor subtype, its lack of prognostic value on univariate analysis suggests an expanded study to evaluate effect modification. The absence of a specific gene classifier for VHL mutation and the lack of association between VHL gene mutation and known hypoxia response genes suggest that VHL mutations result in heterogenous tissue phenotypes. These results support molecular subtyping of ccRCC in laboratory and clinical studies; in particular, this may be critical for trials involving anti-angiogenesis agents.

No significant financial relationships to disclose.

Autologous stem cell transplantation followed by consolidation chemotherapy for patients with multiple myeloma

Although high-dose therapy and autologous stem cell transplant (ASCT) is superior to conventional chemotherapy for treatment of myeloma, most patients relapse and the time to relapse depends upon the initial prognostic factors. The administration of non-cross-resistant chemotherapies during the post-transplant period may delay or prevent relapse. We prospectively studied the role of consolidation chemotherapy (CC) after single autologous peripheral blood stem cell transplant (auto-PBSCT) in 103 mostly newly diagnosed myeloma patients (67 patients were < or =6 months from the initial treatment). Patients received conditioning with BCNU, melphalan+/-gemcitabine and auto-PBSCT followed by two cycles of the DCEP+/-G regimen (dexamethasone, cyclophosphamide, etoposide, cisplatin+/-gemcitabine) at 3 and 9 months post-transplant and alternating with two cycles of DPP regimen (dexamethasone, cisplatin, paclitaxel) at 6 and 12 months post-transplant. With a median follow-up of 61.2 months, the median event-free survival (EFS) and overall survival (OS) are 26 and 54.1 months, respectively. The 5-year EFS and OS are 23.1 and 42.5%, respectively. Overall, 51 (49.5%) patients finished all CC, suggesting that a major limitation of this approach is an inability to deliver all planned treatments. In order to improve results following autotransplantation, novel agents or immunologic approaches should be studied in the post-transplant setting.

Upregulation and activation of PKC alpha by ErbB2 through Src promotes breast cancer cell invasion that can be blocked by combined treatment with PKC alpha and Src inhibitors

Although ErbB2 is known to enhance breast cancer metastasis, the signaling events responsible for this remain elusive. Alpha-isozyme of protein kinase C (PKCalpha), which is involved in cancer development and progression, has been suggested to be activated by ErbB2 without direct evidence. In addition, the roles of PKCalpha in ErbB2-mediated cancer cell malignancy have not been clearly identified. In this study, we investigated whether ErbB2 can activate PKCalpha and determined what role PKCalpha plays in ErbB2-mediated breast cancer cell invasion. We expressed wild-type and mutant ErbB2 with altered signaling capacities in MDA-MB-435 breast cancer cells and revealed that overexpression or activation of ErbB2 in MDA-MB-435 cells upregulated and activated PKCalpha and that downregulation of ErbB2 by small-interfering RNA decreased the expression and activity of PKCalpha in BT474 breast cancer cells. These in vitro results were supported by data from breast cancer patient samples. In 150 breast cancer tumor samples, ErbB2-overexpressing tumors showed significantly higher positive rates of PKCalpha membrane immunohistochemistry staining than that of ErbB2-low-expressing tumors. Mechanistically, we found that PKCalpha is co-immunoprecipitated with Src and PKCalpha expression and activity can be decreased by Src inhibitor PP2 and by the expression of a dominant-negative mutant of Src. Moreover, ErbB2-mediated upregulation of urokinase-type plasminogen activator receptor (uPAR) is reduced by either the PKCalpha inhibitor Go6976 or the Src inhibitor PP2, and the combination of Go6976 with PP2 is superior to either agent alone in suppressing uPAR expression and cell invasion. These results demonstrate that PKCalpha is critical for ErbB2-mediated cancer cell invasion and provide valuable insights for current and future PKCalpha and Src inhibitor clinical trials.

Mucormycosis presenting with painful ophthalmoplegia

Mucormycosis is a rare fungal infection that can involve the sino-orbito-cerebral region. Sino-orbito-cerebral mucormycosis is most common in patients who are immunocompromised or have diabetes mellitus, severe malnutrition or burns. This condition can be fatal if it is not diagnosed early and treated aggressively. This article presents 4 cases of mucormycosis, including 2 with orbital apex syndrome, 1 with cavernous sinus syndrome, and 1 with multiple cranial nerve involvement. All of the patients were presented with painful ophthalmoplegia. The predisposing factors for mucormycosis included diabetes mellitus (three patients) and chronic leukemia (one patient). In all cases, mucormycosis was diagnosed by examining endoscopic sinus drainage material and was treated with surgical debridement and amphotericin B. Two patients with central nervous system involvement died. The others have survived, but still exhibiting various neurologic abnormalities after aggressive treatment. Patients with mucormycosis rarely present with orbital apex syndrome. The possibility of mucormycosis should be investigated in any patient with painful ophthalmoplegia, and prompt otorhinolaryngologic examination is recommended to ensure rapid diagnosis and treatment.

Congenital anomaly rate in offspring of mothers with diabetes treated with insulin lispro during pregnancy

AIM

To determine the rate of major congenital anomalies in offspring of a large group of women with diabetes mellitus treated with insulin lispro (Humalog).

METHODS

This multinational, multicentre, retrospective study included mothers with diabetes mellitus (diagnosed prior to conception) who were treated with insulin lispro for at least 1 month before conception and during at least the first trimester of pregnancy. Anomalies were assessed by two independent dysmorphologists not affiliated with the sponsor.

RESULTS

The charts of 496 women were reviewed for 533 pregnancies resulting in 542 offspring (500 live births, 31 spontaneous and seven elective abortions, and four stillbirths). Mothers' characteristics: mean (+/- SD) age was 29.9 (+/- 5.2) years, 85.6% were Caucasian and 97.2% had Type 1 diabetes mellitus. Insulin lispro continued to be the main mealtime insulin for more than 96% of the women during the second and third trimester. The dysmorphologists determined that 27 (5.4%) offspring had major congenital anomalies and 2 (0.4%) offspring had minor congenital anomalies.

CONCLUSIONS

The rate of major congenital anomalies was 5.4% [95% CI (3.45%, 7.44%)] for offspring of mothers with diabetes mellitus treated with insulin lispro before and during pregnancy. The current published rates of major anomalies in infants born to mothers with diabetes treated with insulin are between 2.1 and 10.9%. This suggests that the anomaly rate with insulin lispro treatment does not differ from the published major congenital anomaly rates for other insulin treatments.

Pioglitazone elicits long-term improvements in insulin sensitivity in patients with type 2 diabetes: comparisons with gliclazide-based regimens

AIMS/HYPOTHESIS

Recent studies have demonstrated that pioglitazone (PIO) has beneficial effects on insulin sensitivity compared with placebo in patients with type 2 diabetes. The effects of PIO and gliclazide (GLIC)-based therapy on insulin sensitivity have not previously been directly compared. This analysis aimed to compare the effects of 52 weeks of treatment with PIO (30-45 mg/day) and GLIC (80-320 mg/day), both titrated to maximum tolerable doses, as monotherapy or in combination with metformin (MET), on insulin sensitivity and lipid parameters known to be related to insulin sensitivity in patients with type 2 diabetes.

METHODS

We performed an analysis of 1,880 patients with inadequately controlled type 2 diabetes (HbA1c 7.5-11.0%) who were participants in two parallel-group, double-blind, double-dummy, randomised, multicentre, clinical trials. Measures of insulin sensitivity and lipids were assessed.

RESULTS

The PIO- and GLIC-based regimens produced similar levels of glycaemic control (HbA1c). In both trials, insulin sensitivity as assessed using the homeostasis model assessment was improved in patients receiving PIO, but decreased in those receiving GLIC (mean change, baseline to endpoint: PIO 15.5, GLIC -15.6; p<0.001 and PIO+MET 18.9, GLIC+MET -5.3; p<0.001). Improvements in the atherogenic index of plasma (mean change: PIO -0.17, GLIC -0.08; p<0.001 and PIO+MET -0.17, GLIC+MET -0.02; p<0.001), triglycerides (mean change, mmol/l: PIO+MET -0.62, GLIC+MET -0.22; p<0.001) and NEFA (mean change, mmol/l: PIO+MET -0.12, GLIC+MET-0.05; p<0.001) were greater in PIO-treated patients than in patients receiving GLIC.

CONCLUSIONS/INTERPRETATION

The PIO-based regimens resulted in improved insulin sensitivity and more favourable insulin sensitivity-related lipid profiles compared with the GLIC-based regimens. These benefits may be important in the management of cardiovascular risk in patients with type 2 diabetes.

The value of Bilicheck as a screening tool for neonatal jaundice in term and near-term babies

AIMS

To determine the accuracy of Bilicheck in assessing serum bilirubin. To evaluate the effectiveness of Bilicheck as a screening device in a population of jaundiced term and near-term babies.

METHODS

Prospective evaluation of paired Bilicheck measurements and serum bilirubin in 300 babies.

RESULTS

There was a strong correlation between Bilicheck and serum bilirubin. The mean difference between Bilicheck and serum bilirubin was -10.7 micromol/l, but the 95% limits of agreement were wide at -80 micromol/l to +60 micromol/l. Bilicheck identified significant jaundice (serum bilirubin above 250 micromol/l) with a sensitivity (95% confidence interval) of 91% (88% to 94%) and specificity of 66% (60% to 71%). The area under the receiver operator characteristic curve was 0.85. There were five false negatives, all of whom had a serum bilirubin below 300 micromol/l. If Bilicheck had been used as a screening device, there would have been a 55% decrease in blood samples taken in these babies.

CONCLUSION

Bilicheck cannot be used to measure serum bilirubin in term and near-term babies with jaundice, but is an effective screening method, which can be used to safely reduce the number of blood tests in these babies.

Attention deficit and hyperactivity disorder, methylphenidate, and epilepsy

Attention deficit hyperactivity disorder (ADHD) is characterised by inattention, impulsivity, and hyperactivity. The DSM-IV diagnosis of ADHD requires the presence of six of nine items or features that must have been present for at least six months, to have had an onset before 7 years of age, and to have resulted in significant distress or impairment.1 In the general population, the prevalence of ADHD is approximately 5%.2 There is a high co-morbidity of epilepsy and attentional and behavioural problems,3,4 including ADHD, and it has been estimated that at least 20% of patients with epilepsy may present with features of ADHD.5.

Breath carbon monoxide as an indication of smoking habit in the military setting

INTRODUCTION

The breath carbon monoxide (CO) monitor has been shown to be an effective tool in predicting smoking habits. This study aims to assess whether the breath CO level can be employed to determine a person's smoking habit in the military setting and to analyse various factors that can influence the breath CO levels.

METHODS

155 navy personnel were questioned on their smoking habits in phase one of the study. The subjects were explained the objective of the study and instructed to provide two breaths into the CO monitor (EC-50 Smokerlyser, Bedford Instruments, Kent, UK). In a subsequent single blind study, 40 trainees were not told of the purpose of the study and were assessed via a questionnaire and smokerlyser estimation. Descriptive statistics were used to examine the data and assess distribution. Depending on the distribution, a two-sample t test or Mann-Whitney U test were used to test for a significant difference between CO levels among smokers and non-smokers.

RESULTS

In phase one, the mean breath CO levels were 11.6 (plus or minus 6.2) ppm for smokers and (1.9 plus or minus 0.9) ppm for non-smokers (p-value less than 0.0001). A cut-off level of 5 ppm gave a sensitivity of 96 percent and a specificity of 98 percent. The high CO levels were clustered within five hours of the last cigarette smoked. Therefore, this value may not reliably predict smoking habits if an individual smoked more than five hours before the test. Of the 40 subjects in phase two, five smokers who stated that their last cigarette smoked was 48 hours before the breath test had a mean CO level greater than 5 ppm. (range of 5.5 to 18.0 ppm). On further questioning, all admitted to having smoked on the day of the test.

CONCLUSION

The breath CO monitor has good potential for use as an adjunct in future smoking control assessments and a reading greater than 5 ppm strongly suggests that the military outpatient is a smoker.

Role of zinc in the pathogenesis and treatment of prostate cancer: critical issues to resolve

The most consistent and persistent biochemical characteristic of prostate cancer (PCa) is the marked decrease in zinc and citrate levels in the malignant cells. This relationship provides compelling evidence that the lost ability of the malignant cells to accumulate zinc is an important factor in the development and progression of prostate malignancy. In addition, this relationship provides a rational basis for the concept that restoration of high zinc levels in malignant cells could be efficacious in the treatment and prevention of PCa. Epidemiological studies regarding dietary zinc effects on PCa have been conflicting and confusing. The purpose of this presentation is to present a current state of information regarding zinc relationships in the pathogenesis and treatment of PCa. We also hope to bring more attention to the medical and research community of the critical need for concerted clinical and basic research regarding zinc and PCa.

Activation of a rice endogenous retrotransposon Tos17 in tissue culture is accompanied by cytosine demethylation and causes heritable alteration in methylation pattern of flanking genomic regions

Tos17 is a copia-like, cryptic retrotransposon of rice, but can be activated by tissue culture. To study possible epigenetic mechanism controlling activity of Tos17, we subjected three rice lines (the parental line cv. Matsumae and two introgression lines, RZ2 and RZ35) that harbor different copies of the element to tissue culture. For each line, we investigated transcription and transposition of Tos17 in seed plants, calli and regenerated plants, cytosine-methylation status at CG and CNG positions within Tos17, effect of 5-azacytidine on methylation status and activity of Tos17, and cytosine-methylation states in genomic regions flanking original and some newly transposed copies of Tos17 in calli and regenerated plants. We found that only in introgression line RZ35 was Tos17 transcriptionally activated and temporarily mobilized by tissue culture, which was followed by repression before or upon plant regeneration. The activity and inactivity of Tos17 in calli and regenerated plants of RZ35 are accompanied by hypo- and hyper-CG methylation and hemi- and full CNG methylation, respectively, within the element, whereas immobilization of the element in the other two lines is concomitant with near-constant, full hypermethylation. Treatment with 5-azacytidine induced both CG and CNG partial hypomethylation of Tos17 in two lines (Matsumae and RZ35), which, however, was not accompanied by activation of Tos17 in any line. Heritable alteration in cytosine-methylation patterns occurred in three of seven genomic regions flanking Tos17 in calli and regenerated plants of RZ35, but in none of the five regions flanking dormant Tos17 in the other two lines.