Yap governs a lineage-specific neuregulin1 pathway-driven adaptive resistance to RAF kinase inhibitors

BACKGROUND

Inactivation of the Hippo pathway promotes Yap nuclear translocation, enabling execution of a transcriptional program that induces tissue growth. Genetic lesions of Hippo intermediates only identify a minority of cancers with illegitimate YAP activation. Yap has been implicated in resistance to targeted therapies, but the mechanisms by which YAP may impact adaptive resistance to MAPK inhibitors are unknown.

METHODS

We screened 52 thyroid cancer cell lines for illegitimate nuclear YAP localization by immunofluorescence and fractionation of cell lysates. We engineered a doxycycline (dox)-inducible thyroid-specific mouse model expressing constitutively nuclear YAP^S127A, alone or in combination with endogenous expression of either Hras^G12V or Braf^V600E. We also generated cell lines expressing dox-inducible sh-miR-E-YAP and/or YAP^S127A. We used cell viability, invasion assays, immunofluorescence, Western blotting, qRT-PCRs, flow cytometry and cell sorting, high-throughput bulk RNA sequencing and in vivo tumorigenesis to investigate YAP dependency and response of BRAF-mutant cells to vemurafenib.

RESULTS

We found that 27/52 thyroid cancer cell lines had constitutively aberrant YAP nuclear localization when cultured at high density (NU-YAP), which rendered them dependent on YAP for viability, invasiveness and sensitivity to the YAP-TEAD complex inhibitor verteporfin, whereas cells with confluency-driven nuclear exclusion of YAP (CYT-YAP) were not. Treatment of BRAF-mutant thyroid cancer cells with RAF kinase inhibitors resulted in YAP nuclear translocation and activation of its transcriptional output. Resistance to vemurafenib in BRAF-mutant thyroid cells was driven by YAP-dependent NRG1, HER2 and HER3 activation across all isogenic human and mouse thyroid cell lines tested, which was abrogated by silencing YAP and relieved by pan-HER kinase inhibitors. YAP activation induced analogous changes in BRAF melanoma, but not colorectal cells.

CONCLUSIONS

YAP activation in thyroid cancer generates a dependency on this transcription factor. YAP governs adaptive resistance to RAF kinase inhibitors and induces a gene expression program in BRAF^V600E-mutant cells encompassing effectors in the NRG1 signaling pathway, which play a central role in the insensitivity to MAPK inhibitors in a lineage-dependent manner. HIPPO pathway inactivation serves as a lineage-dependent rheostat controlling the magnitude of the adaptive relief of feedback responses to MAPK inhibitors in BRAF-^V600E cancers.

Co-inhibition of SMAD and MAPK signaling enhances 124I uptake in BRAF-mutant thyroid cancers

Constitutive MAPK activation silences genes required for iodide uptake and thyroid hormone biosynthesis in thyroid follicular cells. Accordingly, most BRAFV600E papillary thyroid cancers (PTC) are refractory to radioiodide (RAI) therapy. MAPK pathway inhibitors rescue thyroid-differentiated properties and RAI responsiveness in mice and patient subsets with BRAFV600E-mutant PTC. TGFB1 also impairs thyroid differentiation and has been proposed to mediate the effects of mutant BRAF. We generated a mouse model of BRAFV600E-PTC with thyroid-specific knockout of the Tgfbr1 gene to investigate the role of TGFB1 on thyroid-differentiated gene expression and RAI uptake in vivo. Despite appropriate loss of Tgfbr1, pSMAD levels remained high, indicating that ligands other than TGFB1 were engaging in this pathway. The activin ligand subunits Inhba and Inhbb were found to be overexpressed in BRAFV600E-mutant thyroid cancers. Treatment with follistatin, a potent inhibitor of activin, or vactosertib, which inhibits both TGFBR1 and the activin type I receptor ALK4, induced a profound inhibition of pSMAD in BRAFV600E-PTCs. Blocking SMAD signaling alone was insufficient to enhance iodide uptake in the setting of constitutive MAPK activation. However, combination treatment with either follistatin or vactosertib and the MEK inhibitor CKI increased 124I uptake compared to CKI alone. In summary, activin family ligands converge to induce pSMAD in Braf-mutant PTCs. Dedifferentiation of BRAFV600E-PTCs cannot be ascribed primarily to activation of SMAD. However, targeting TGFβ/activin-induced pSMAD augmented MAPK inhibitor effects on iodine incorporation into BRAF tumor cells, indicating that these two pathways exert interdependent effects on the differentiation state of thyroid cancer cells.

Service users' experiences of receiving a diagnosis of borderline personality disorder: A systematic review

There is ongoing controversy regarding the borderline personality disorder (BPD) diagnosis. Whilst the experiences of people living with BPD have been widely acknowledged, the process of receiving the diagnosis is poorly described. This systematic review aimed to synthesize the existing research exploring people's experiences of receiving a diagnosis of BPD, as well as examining what is considered best practice in the diagnostic delivery process. The findings from 12 qualitative studies were synthesized using thematic analysis, generating two overarching themes: negative and positive experiences of receiving a diagnosis of BPD. These themes were described using the following sub-themes: the communication of diagnosis and meaning made of it, validity around diagnosis and attitudes of others. Results indicate that there is a substantial difference between a well-delivered and poorly delivered diagnosis. The diagnostic delivery process is fundamental to how people understand and interpret the BPD diagnosis. The way in which the BPD diagnosis is shared with people can ultimately shape their views about hope for recovery and their subsequent engagement with services. © 2020 John Wiley & Sons, Ltd.

1036 Does Diary and Actigraphy Measured Sleep Differ Between Good and Poor Sleepers During Breast Cancer Treatment?

Introduction

Women may enter in breast cancer (BCa) treatment with poor sleep, or it may begin during treatment. We assessed how subjective and objective sleep changes during the first year of treatment for women with BCa. Further, we examined whether this differs between previously good and poor sleepers and whether there was agreement between subjective and objective measures of sleep.

Methods

Sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE) were measured among 100 patients with newly diagnosed, non-metastatic BCa using 7 days of diary and actigraphy collected at 4 time points: pre-treatment, 4, 8, and 12 months. Women with a score ≥5 on the Pittsburgh Sleep Quality Index at treatment onset were classified as poor sleepers. A 4 (time: 0-, 4-, 8-, 12-months) by 2 (sleep measure: sleep diary, actigraphy) by 2 (group: good, poor sleepers) mixed model ANOVAs was performed for each sleep parameter.

Results

There was a time by sleep measure by group interaction for TST, [F(3,294)= 3.014, p = .03). Good sleepers reported greater TST on diaries- than actigraphy at pre-treatment and 12 months, whereas there were no differences in poor sleepers. There was a group by time effect for good vs. poor sleepers [F(3,294)= 2.909, p = .035]. Good sleepers experienced decreased TST and SE from pre-treatment through 4-mo, followed by increases. Poor sleepers showed the opposite pattern. Neither group returned to pre-treatment levels. Sleep diaries and actigraphy are concordant over time for TST, but not SOL, WASO, or SE.

Conclusion

Sleep parameters worsen during the first year following onset of BCa and concordance between sleep diaries and actigraphy differ between good or poor sleepers.

Support

Dr. Garland is supported by a Scotiabank New Investigator Award and seed funding from the Beatrice Hunter Cancer Research Institute (BHCRI).

1030 An Exploration of the Impact of Cognitive Behavioural Therapy of Insomnia (CBT-I) on Perceived Cognitive Impairment in Breast Cancer Survivors

Introduction

Insomnia and cognitive impairment are prevalent and persistent symptoms in cancer survivors. Cognitive Behavior Therapy is effective for improving insomnia and comorbid symptoms in cancer survivors but there are very few empirically supported treatments that can improve cognitive impairment. This feasibility study explored the impact of CBT-I on perceived cognitive impairment in breast cancer survivors.

Methods

We enrolled 10 early stage breast cancer survivors with insomnia disorder and perceived cognitive impairment. Participants received 7 individual sessions of CBT-I over the course of 8 weeks and completed the Insomnia Severity Index (ISI), the Functional Assessment of Cancer Therapy - Cognitive Function (FACT-Cog) questionnaires and The Hospital Anxiety and Depression Scale (HADS) at baseline and post-treatment. Paired samples t-tests were used to assess change over time.

Results

The sample was predominantly diagnosed with stage II breast cancer (60%). Women were an average age of 50.8 (SD 6.84) and 18.2 (SD 3.62) years of education. CBT-I significantly reduced insomnia severity [19.4 to 7.1; t(9)= 6.56, p < .001] and improved perceived cognitive impairment [t(9)= -3.55, p < .01], perceived cognitive ability [t(9)= -2.87, p < .05], quality of life [t(9)= -3.14, p < .05], and overall subjective cognitive function [t(9)= -3.67, p < .01]. Although participants began treatment with low levels of mood disturbance, CBT-I further decreased symptoms of anxiety (baseline: M= 10.10, SD= 4.34; post-treatment M= 8.20, SD= 3.91) and depression (baseline: M= 7.90, SD= 3.45; post-treatment M= 5.30, SD= 2.83), although not statistically significant.

Conclusion

This study suggests CBT-I may improve perceived cognitive impairment in cancer survivors, in addition to insomnia and mood. Future randomized controlled trials with larger samples and objective measurements of cognition are needed.

Support

Nyissa Walsh is a trainee in the Cancer Research Training Program of the Beatrice Hunter Cancer Research Institute (BHCRI). Dr. Sheila Garland is supported by a Scotiabank New Investigator Award from BHCRI.

Advances in the systemic treatment of triple-negative breast cancer

Triple-negative breast cancer constitutes a heterogeneous group of malignancies that are often aggressive and associated with a poor prognosis. Molecular characterization, while not a standard of care, can further subtype triple-negative breast cancer and provide insight into prognostication and behaviour. Optimal chemotherapy regimens have yet to be established; however, there have been advances in the systemic treatment of triple-negative breast cancer in the neoadjuvant, adjuvant, and metastatic settings. In this review, we discuss evidence for the potential benefit of neoadjuvant platinum-based chemotherapy, adjuvant combination chemotherapy with weekly paclitaxel, and BRCA mutation-directed therapy in the metastatic setting. The role for adjuvant capecitabine in patients who do not achieve a pathologic complete response with neoadjuvant chemotherapy is reviewed. Future directions and data concerning novel targeted agents are reviewed, including the most recent data on parp [poly (adp-ribose) polymerase] inhibitors, antiandrogen agents, and immunotherapy.

Sex pheromones of rice moth,Corcyra cephalonica Stainton : I. Identification of male pheromone

Behavioral observations of the rice moth (Corcyra cephalonica, Pyralidae, Galleriinae) in the laboratory have shown that a male wing-gland pheromone induces attraction of female moths. This pheromone was identified as a blend of (E,E) and (Z,E)-farnesal. Wing-gland extracts or synthetic compounds were shown to be attractive to females by inducing walking.

Sex pheromones of rice moth,Corcyra cephalonica Stainton : II. Identification and role of female pheromone

Laboratory investigations of mating behavior in the rice moth,Corcyra cephalonica Stainton (Lepidoptera: Pyralidae; Galleriinae) showed that male moths are attracted at short range to live, virgin female moths and to female abdominal-tip extract. Volatiles collected from virgin female moths contained one component eliciting an electroantennographic (EAG) response from the male moth, and the chemical, spectroscopic, and Chromatographic data on this component were consistent with that of synthetic 6,10,14-tri-methyl-2-pentadecanol. This compound caused an EAG response from the male moth and attracted male moths in the bioassay. The pheromone is thought to play a role in courtship, and the synthetic material was shown to cause the male moths to search for a mate and attempt copulation.

Macrodactyly - options and outcomes

We report the outcomes of 32 patients diagnosed with macrodactyly. The average age at presentation was 46 months and there was an equal distribution across the sexes, although there was a male predominance in the upper limb and female predominance in the lower limb. There were 20 cases of upper limb macrodactyly and 13 cases affecting the lower limb. Multiple digits were more commonly affected than isolated digits, with an average of 2.5 digits affected. Static disease required significantly fewer operations than progressive disease. The need for repeated procedures must be highlighted in cases of progressive macrodactyly. In the vast majority of cases the functional and cosmetic outcome is good, with good patient acceptance.

Direct-acting antiviral therapies for hepatitis C genotype 1 infection: a multiple treatment comparison meta-analysis

BACKGROUND

New direct-acting antiviral agents for hepatitis C genotype 1 infection, boceprevir and telaprevir, offer enhanced sustained virologic response (SVR) among both treatment-naïve and treatment-experienced patients.

AIM

To determine the relative efficacy of the new direct-acting antiviral agents by applying a multiple treatment comparison meta-analysis.

DESIGN

We included published Phase II and III randomized controlled trials evaluating head-to-head comparisons between boceprevir, telaprevir, peg-interferon alpha-2a with ribavirin and peg-interferon alpha-2b with ribavirin in hepatitis C genotype 1 patients. We applied Bayesian multiple treatment comparison meta-analysis.

RESULTS

We included data from four boceprevir, three telaprevir and six peg-interferon alpha-2a plus ribavirin vs. peg-interferon alpha-2b plus ribavirin randomized controlled trials. Both boceprevir and telaprevir offer statistically superior outcomes for SVR, relapse and discontinuation due to adverse events than either peg-interferons among both treatment-naïve and treatment-experienced patients. Among treatment-naïve patients, clinical outcomes were similar for boceprevir and telaprevir, for SVR [odds ratio (OR) 0.90, 95% credible interval (95% CrI) 0.41-1.91] and for relapse (OR 1.09, 95% CrI 0.19-4.84). Similarly, among treatment-experienced patients, clinical outcomes were similar for boceprevir and telaprevir and for SVR (OR 1.45, 95% CrI 0.70-3.08) and for relapse (OR 0.35, 95% CrI 0.13-1.02). For treatment-naïve patients receiving standard-duration therapy, telaprevir yielded lower rates of anemia and neutropenia, but higher rates of rash and pruritus. For treatment-experience patients, all adverse event rates were higher with telaprevir.

DISCUSSION

Boceprevir and telaprevir exhibit similar effects among hepatitis C genotype 1 treatment-naïve and treatment-experienced patients.

Topical negative pressure for the treatment of neonatal post-sternotomy wound dehiscence

The use of topical negative pressure (TNP) dressings for sternal wound dehiscence or mediastinitis in the neonatal population is rare. The majority of case reports have focused on wound healing as an endpoint and have not discussed the physiological advantage that TNP dressings may impart with regard to sternal stabilisation, improved respiratory function and early weaning from mechanical ventilation. We present a case of the use of TNP in neonatal post-sternotomy wound dehiscence and mediastinitis, from a UK perspective, with an emphasis on wound healing and physiological optimisation. As well as an improvement in sternal wound healing due to the local effects of the TNP system, serial arterial blood gas analysis revealed a significant improvement in systemic physiological parameters, including a reduction in pCO(2) in the period (days 20-31) after application of TNP (p<0.0001) compared to the period before where simple occlusive dressings were applied. Hydrogen ion concentration also significantly reduced in this period (p=0.0058). The use of the TNP system in association with systemic antibiotics successfully treated the mediastinitis. A sealed, controlled wound environment also allowed ease of nursing and an expedited return to care by the parents. We would recommend the consideration of TNP dressings in similar cases of neonatal and paediatric sternal wound dehiscence. Not only do we observe the local effects of improved wound healing, the systemic effects of improved lung function are also valuable in the early management of such complex cases.

Syndactyly correction: an aesthetic reconstruction

Various flaps have been used with and without skin grafts to separate digits with syndactyly. Dorsal flap techniques with and without grafts result in dorsal and thus more visible scars. Some of the recent techniques which use no grafts are only applicable for some simple syndactylies. The technique described in this paper uses a combination of techniques which have been described previously. A shaped palmar flap is used to create the web space; narrow V-flaps and full-thickness skin grafts are used to resurface the lateral defects on the fingers and reciprocal pulp flaps are used to create aesthetically pleasing nail folds. This technique allows the full thickness grafts to be hidden on the radial and ulnar sides of the fingers and palm. It increases the span of the hand in conditions where there is shortage of palmar skin. A retrospective review has been undertaken of 102 patients in whom 221 webs were reconstructed through 176 surgical procedures. There were 54 cases of simple syndactylies (53%) and the rest were complex. Complications were encountered in 11 operations (6%) and web creep was noted in 12 web spaces (5%). Re-operation for web creep has been carried out in seven web spaces (3%).

Hypoplastic thumb in Gorlin's syndrome

Gorlin's syndrome or naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder that predisposes to basal cell carcinomas of the skin, ovarian fibromas, and medulloblastomas. This condition is due to mutations in the Patched (PTCH) gene which maps to chromosome 9q22 and acts as a tumour suppressor gene. Gorlin's syndrome is characterized by the development of multiple jaw keratocysts and/or basal carcinomas. There is a distinctive coarse facial appearance with macrocephaly, frontal bossing and prognathism. Most individuals have skeletal anomalies such as bifid ribs or wedge-shaped vertebrae. We present a case in which the patient presented with bilateral thumb hypoplasia. Various hand deformities have been reported in patients with Gorlin's syndrome including short metacarpals, cutaneous syndactyly of the second and third fingers, and pre- or post-axial polydactyly, but hypoplasia of the thumb has not been reported previously. These features of Gorlin's syndrome may be helpful diagnostically. The thumbs should be examined carefully in Gorlin's syndrome patients as minor degrees of hypoplasia are easy to miss. However, they still needs a specialist input to give the patient an optimum function of the thumb and the hand.

An observational study of sun and heat protection during Canada Day outdoor celebration, 2003

Attendance at summer outdoor mass gatherings may lead to heat- and sun-related illness. The purposes of this study were: (1) to estimate the proportion of people in attendance at the 2003 Canada Day celebration in the National Capital Region who used sun and heat protective items; (2) to identify factors associated with the utilization of these protective items; and (3) to provide research data to public outdoor event organizers when developing evidence-based plans for safer events. A naturalistic observational cross-sectional method was used to gather information at the 2003 Canada Day celebration in the National Capital Region on attendees' demographics, the sun and heat protective items they used and the protective resources available at the event sites. Of the 398 observed attendees, the proportion using any one of the protective items ranged from 3 percent (an open umbrella) to 51.5 percent (sunglasses). Females were more likely to use protective items more than males, and adults more likely than children. Planners of public outdoor events should consider the factors that influence the utilization of sun and heat protective behaviours and the environmental modifications that would allow participants to make safe choices.

Lower body anatomical distribution of solar ultraviolet radiation on the human form in standing and sitting postures

Humans undertake their daily activities in a number of different postures. This paper aims to compare the anatomical distribution of the solar erythemal UV to human legs for standing and sitting postures. The exposure ratios to the legs (ratio of the UV exposure to a particular anatomical site compared to the ambient) have been measured with UV dosimeters for standing and sitting postures of a manikin. The exposure ratios for the legs ranged from 0 to 0.75 for the different anatomical sites for the sitting posture in summer (December through February) compared to 0.14 to 0.39 for the standing posture. In winter (June through August) the exposure ratios ranged from 0.01 to 0.91 for sitting to 0.17 to 0.81 for standing. For the anterior thigh and shin, the erythemal UV exposures increased by a factor of approximately 3 for sitting compared to standing postures. The exposure ratios to specific anatomical sites have been multiplied by the ambient erythemal UV exposures for each day to calculate the annual exposures. The annual erythemal exposures to the anterior thigh and ankle were predicted to be higher than 800 MED for humans sitting outdoors each day between noon and 13:00 h Australian Eastern Standard Time (EST). For humans standing outdoors during this time, the annual erythemal UV exposure averaged over each leg site was 436 MED, whereas, the averaged annual erythemal UV exposure was 512 MED for the sitting posture. Similarly, the annual erythemal UV exposure averaged over each of the sites was 173 MED for humans standing outdoors between 09:00 h EST and noon each Saturday morning and 205 MED for humans sitting outdoors during this time. These results show that there is increased risk of non-melanoma skin cancer and malignant melanoma to the lower body if no UV preventative strategies are employed while in a sitting posture compared to a standing posture.

Comparison between seasons of the ultraviolet environment in the shade of trees in Australia

BACKGROUND/PURPOSE

This paper has considered the erythemal UV (UVery), UVA and visible irradiances in the shade of Australian trees for each season at a sub-tropical southern hemisphere site.

METHODS

The irradiances in tree shade have been measured with radiometers as a percentage of the irradiances in the sun for each season of the year.

RESULTS

Although the solar irradiances are lower in winter, the percentages of the UV in tree shade compared to the UV in full sun are marginally higher (by up to 7%) in the winter compared to summer. The range of percentages for UVery was up to double that of the percentages of the visible waveband. The percentages for UVery were also higher than for the UVA waveband. The percentages of the irradiances in the tree shade compared to full sun are 8-14% lower at noon compared to the morning and afternoon for the UVery waveband. The ratio of UVA to UVery is lower in the tree shade compared to the full sun.

CONCLUSIONS

The UVA to UVery ratio is expected to be even lower in the tree shade as a result of ozone depletion. This, combined with the visible irradiances in the tree shade not being a reliable indication of the biologically damaging UV irradiances, has consequences for public health and skin cancer prevention.

Randomised controlled trial of an educational strategy to increase school-based adolescent hepatitis B vaccination

OBJECTIVES

This study aimed to evaluate a specifically designed hepatitis B education/promotion curriculum package as part of a successful hepatitis B vaccination delivery system to adolescents.

METHODS

A randomised-controlled trial was used to evaluate the effect of the curriculum package (or intervention) on uptake of vaccine. Schools were randomly selected from the metropolitan region of Melbourne to intervention (66 schools or 7,588 students) or control groups (69 schools or 9,823 students). Class teachers administered the intervention to students over 4 class periods before the vaccination course.

RESULTS

The difference in mean school uptake between intervention and control was small at 1-2% per dose. 95% confidence intervals around the differences were -5% to 2% per dose and not significant. Intervention schools taught an average of 7 items out of 12 from the curriculum package. Immunisation rates increased by 4-10% per dose between low and high implementation schools, but this trend was not significant. Impact evaluation demonstrated significantly greater knowledge of hepatitis B and vaccination among students in the intervention than the control group.

CONCLUSION

Hepatitis B vaccination of pre-adolescents was not increased by the implementation of a curriculum package that successfully increased knowledge and awareness of hepatitis B in a school-based vaccination program. Additional strategies directed at the education of parents, the cooperative role of schools and pro-active providers might also be required to maximise vaccine uptake in this age group.

Open-label study to evaluate the healing rate and safety of the Profore Extra Four-Layer Bandage System in patients with venous leg ulceration

BACKGROUND

Venous ulcers are increasing in prevalence, especially since these are observed more frequently in the elderly, and the number of individuals in this age group is becoming a larger portion of the population.

OBJECTIVE

To determine the healing rate and safety of the Profore Extra Four-Layer Bandage System in the management of venous leg ulcers.

METHODS

In an open-label study, patients aged 18 years or older with venous leg ulcers were treated with a high compression four-layer bandage system in which a hydrocellular dressing was placed in contact with the wound. The combination is designated the "Profore Extra Four-Layer Bandage System." Follow-up visits took place weekly unless there was heavy exudation from the ulcer or if there was marked edema of the leg at the start of the study requiring reapplication of the bandage system.

RESULTS

Fifteen patients were entered into the study (men 8, women 7, mean age 66 years, mean duration of ulcers 1.3 years). Thirteen of the 15 patients completed the study, with two withdrawals. In one patient who withdrew, the ulcer became infected and required treatment with antibiotics. The other termination from the study occurred for reasons unrelated to treatment. The ulcer in this patient healed in 7 weeks. Ten of the 13 patients (77%) who completed the study, and 10 (67%) of 15, who had enrolled experienced complete (100%) healing. Healing of > 80% of the ulcers occurred in 11 of 13 patients (85%) who completed the study and in 12 (80%) of 15 enrolled patients. No patient experienced a study-related adverse event. One patient developed contact dermatitis and was later found to have stasis dermatitis. It is unclear whether the initial event was contact or stasis dermatitis.

CONCLUSION

In this open-label study, a high compression system, using the Profore Extra Four-Layer Bandage with a hydrocellular dressing in contact with the wound, was found to be effective and safe for the treatment of venous leg ulcers.

Variability of human hepatic UDP-glucuronosyltransferase activity

The availability of a unique series of liver samples from human subjects, both control patients (9) and those with liver disease (6; biliary atresia (2), retransplant, chronic tyrosinemia type I, tyrosinemia, Wilson's disease) allowed us to characterize human hepatic UDP-glucuronosyltransferases using photoaffinity labeling, immunoblotting and enzymatic assays. There was wide inter-individual variation in photoincorporation of the photoaffinity analogs, [32P]5-azido-UDP-glucuronic acid and [32P]5-azido-UDP-glucose and enzymatic glucuronidation of substrates specific to the two subfamilies of UDP-glucuronosyltransferases. However, the largest differences were between subjects with liver disease. Glucuronidation activities toward one substrate from each of the UDP-glucuronosyltransferases subfamilies, 1A and 2B, for control and liver disease, respectively, were 1.7-4.5 vs 0.4-4.7 nmol/mg x min for hyodeoxycholic acid (2B substrate) and 9.2-27.9 vs 8.1-75 nmol/mg x min for pchloro-m-xylenol (1A substrate). Microsomes from a patient with chronic tyrosinemia (HL32) photoincorporated [32P]5-azido-UDP-glucuronic acid at a level 1.5 times higher than the other samples, was intensely photolabeled by [32P]5-azido-UDP-glucose and had significantly higher enzymatic activity toward p-chloro-m-xylenol. Immunoblot analysis using anti-UDP-glucuronosyltransferase antibodies demonstrated wide inter-individual variations in UDP-glucuronosyltransferase protein with increased UDP-glucuronosyltransferase protein in HL32 microsomes, corresponding to one of the bands photolabeled by both probes. Detailed investigation of substrate specificity, using substrates representative of both the 1A (bilirubin, 4-nitrophenol) and 2B (androsterone, testosterone) families was carried out with HL32, HL38 (age and sex matched control) and HL18 (older control). Strikingly increased (5-8-fold) glucuronidation activity was seen in comparison to HL18 only with the phenolic substrates. The results indicate that one or more phenol-specific UDP-glucuronosyltransferase 1A isoforms are expressed at above normal levels in this tyrosinemic subject.

Immunisation uptake, services required and government incentives for users of formal day care

OBJECTIVES

To determine immunisation uptake in children attending formal day care prior to the introduction of certificates (state) and parent incentives (federal), and to document parent and child carers' attitudes to these strategies.

METHOD

In 1997, 60 child care centres and 300 family day carers in suburban Melbourne were randomly sampled. Immunisation dates, service use and preference, and views on government incentives were obtained from parents of children under three years of age.

RESULTS

From 2,454 eligible children, information was obtained for 1,779, of whom 84% (95% CI 82-86) were completely immunised. Low income (OR 1.8, 95% CI 1.2-1.9, p < or = 0.001) and larger family size (OR 1.8, 95% CI 1.2-2.7, p = 0.002) and only ever using a doctor (OR 1.6, 95% CI 1.1-2.3) was associated with incomplete immunisation. Main reasons for delaying immunisation were occurrence of minor illness and work commitments. Families would prefer immunisation services at Maternal and Child Health visits (39%), evening sessions (22%) and at day care (22%). Immunisation uptake could increase to 94% if those receiving Childcare Assistance (67%) immunised their children on time but would increase to 87% if these incentive only motivated those for whom Childcare Assistance was essential (15%). While 98% of day care co-ordinators and 71% of family day care co-ordinators documented immunisation status at commencement of child care, only 51% and 33% respectively regularly updated this information.

CONCLUSION

Providing client-focused, flexible immunisation services and government incentives and legislation may work together to boost immunisation levels for those in formal child care.

Variability of human hepatic UDP-glucuronosyltransferase activity

The availability of a unique series of liver samples from human subjects, both control patients (9) and those with liver disease (6; biliary atresia (2), retransplant, chronic tyrosinemia type I, tyrosinemia, Wilson's disease) allowed us to characterize human hepatic UDP-glucuronosyltransferases using photoaffinity labeling, immunoblotting and enzymatic assays. There was wide inter-individual variation in photoincorporation of the photoaffinity analogs, [32P]5-azido-UDP-glucuronic acid and [32P]5-azido-UDP-glucose and enzymatic glucuronidation of substrates specific to the two subfamilies of UDP-glucuronosyltransferases. However, the largest differences were between subjects with liver disease. Glucuronidation activities toward one substrate from each of the UDP-glucuronosyltransferases subfamilies, 1A and 2B, for control and liver disease, respectively, were 1.7-4.5 vs 0.4-4.7 nmol/mg x min for hyodeoxycholic acid (2B substrate) and 9.2-27.9 vs 8.1-75 nmol/mg x min for pchloro-m-xylenol (1A substrate). Microsomes from a patient with chronic tyrosinemia (HL32) photoincorporated [32P]5-azido-UDP-glucuronic acid at a level 1.5 times higher than the other samples, was intensely photolabeled by [32P]5-azido-UDP-glucose and had significantly higher enzymatic activity toward p-chloro-m-xylenol. Immunoblot analysis using anti-UDP-glucuronosyltransferase antibodies demonstrated wide inter-individual variations in UDP-glucuronosyltransferase protein with increased UDP-glucuronosyltransferase protein in HL32 microsomes, corresponding to one of the bands photolabeled by both probes. Detailed investigation of substrate specificity, using substrates representative of both the 1A (bilirubin, 4-nitrophenol) and 2B (androsterone, testosterone) families was carried out with HL32, HL38 (age and sex matched control) and HL18 (older control). Strikingly increased (5-8-fold) glucuronidation activity was seen in comparison to HL18 only with the phenolic substrates. The results indicate that one or more phenol-specific UDP-glucuronosyltransferase 1A isoforms are expressed at above normal levels in this tyrosinemic subject.

Formation of adeno-associated virus circular genomes is differentially regulated by adenovirus E4 ORF6 and E2a gene expression

A central feature of the adeno-associated virus (AAV) latent life cycle is persistence in the form of both integrated and episomal genomes. However, the molecular processes associated with episomal long-term persistence of AAV genomes are only poorly understood. To investigate these mechanisms, we have utilized a recombinant AAV (rAAV) shuttle vector to identify circular AAV intermediates from transduced HeLa cells and primary fibroblasts. The unique structural features exhibited by these transduction intermediates included circularized monomer and dimer virus genomes in a head-to-tail array, with associated specific base pair alterations in the 5' viral D sequence. In HeLa cells, the abundance and stability of AAV circular intermediates were augmented by adenovirus expressing the E2a gene product. In the absence of E2a, adenovirus expressing the E4 open reading frame 6 gene product decreased the abundance of AAV circular intermediates, favoring instead the linear replication form monomer (Rfm) and dimer (Rfd) structures. In summary, the formation of AAV circular intermediates appears to represent a new pathway for AAV genome conversion, which is consistent with the head-to-tail concatemerization associated with latent-phase persistence of rAAV. A better understanding of this pathway may increase the utility of rAAV vectors for gene therapy.

Salmonella in Victoria, 1997: the story so far

The Infectious Diseases Unit of the Department of Human Services, Victoria, reported an increased incidence of Salmonella infections in early 1997. To 21 April 1997, 944 notifications had been received, passing the previous year's total of 915. Five outbreaks of five separate serovars have been investigated and traced to their sources. The outbreaks, their sources and the control measures undertaken are described. Further clusters of other Salmonella serovars are being investigated.

A case of human anthrax in Victoria

A human case of anthrax was identified through surveillance of knackery workers who had been exposed to infected cattle. The outbreak in cattle has affected 38 herds in the Stanhope/Tatura area of central northern Victoria. The human case, a 39 year old male, was treated in hospital and is recovering. Surveillance of other knackery workers has now been completed, and no other cases were found. Public health measures are in place to prevent further human cases.

Two kinetically-distinct components of UDP-glucuronic acid transport in rat liver endoplasmic reticulum

Previous studies have documented the presence of protein-mediated transport of UDP-glucuronic acid (UDP-GlcUA) in rat liver endoplasmic reticulum (ER). Measurement of uptake at varying concentrations of high specific activity [beta-32P]UDP-GlcUA has revealed the presence of a two component UDP-GlcUA transporting system. Transport at low substrate concentrations occurred predominantly via a high affinity component (K(m) = 1.6 microM), whereas a low affinity component (K(m) = 38 microM) predominated at high substrate concentrations. The K(m) for the high affinity system is in agreement with that previously published, while the low affinity component is a new finding. The uptake of UDP-GlcUA was temperature-sensitive, time dependent, and saturable for both components. The high affinity transport was affected by trans-stimulation and cis-inhibition by UDP-N-acetylglucosamine (UDP-GlcNAc); however, the same concentrations of UDP-GlcNAc had less effect on the low affinity system. In order to further study the two transport components, various inhibitors of anion transport carriers were tested. The high affinity component was strongly inhibited by 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and furosemide, while the low affinity system was less sensitive to these reagents. Dose-dependent inhibition by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) was found for both transport systems. Probenecid was found to be a weak inhibitor of both components of the UDP-GlcUA uptake. Finally, the major metabolite of 3'-azido-3'-deoxythymidine, 3'-azido-3'-deoxythymidine monophosphate (AZTMP), was able to inhibit the uptake of UDP-GlcUA by both components. The results indicate the presence of two carrier-mediated UDP-glucuronic acid transporting components in rat liver ER.

Photoaffinity labeling of human recombinant sulfotransferases with 2-azidoadenosine 3',5'-[5'-32P]bisphosphate

Photoaffinity labeling with 2-azidoadenosine 3', 5'-[5'-32P]bisphosphate was used to identify and characterize adenosine 3',5'-bisphosphate-binding proteins in human liver cytosol and recombinant sulfotransferase proteins. The sulfotransferases investigated in these studies were the human phenol sulfotransferases, HAST1, -3, and -4, dehydroepiandrosterone sulfotransferase, and estrogen sulfotransferase. The cDNAs for these enzymes have been previously cloned and expressed in COS-7 cells or Escherichia coli. Photoaffinity labeling of all proteins was highly dependent on UV irradiation, was protected by co-incubation with unlabeled adenosine 3',5'-bisphosphate and phosphoadenosine phosphosulfate, and reached saturation at concentrations above 10 microM. To verify that the 31 35-kDa photolabeled proteins were indeed sulfotransferases, specific antibodies known to recognize human sulfotransferases were used for Western blot analyses of photolabeled proteins. It was shown unequivocally that the proteins in the 31-35-kDa region recognized by the antibodies also photoincorporated 2-azidoadenosine 3',5'-[5'-32P]bisphosphate. This is the first application of photoaffinity labeling with 2-azidoadenosine 3',5'-[5'-32P]bisphosphate for the characterization of recombinant human sulfotransferases. Photoaffinity labeling will be also useful in the purification and functional identification of other adenosine 3',5'-bisphosphate-binding proteins and to determine amino acid sequences at or near their active sites.

Characterization of human liver microsomal UDP-glycosyltransferases using photoaffinity analogs

The photoaffinity analogs [beta-32P]5-azido-UDP-glucuronic acid ([32P]5N3UDP-GlcUA) and [beta-32P]5-azido-UDP-glucose ([32P]5N3UDP-Glc) were used to characterize UDP-glycosyltransferases of microsomes prepared from human liver. Photoincorporation of both probes into proteins in the 50- to 56-kdalton range, known to contain UDP-glucuronosyl transferases (UGTs), was concentration dependent, and photolabeled proteins were susceptible to trypsin digestion only in the presence of detergent. The latter was demonstrated by the appearance on Western blots of the trypsin-treated, detergent-disrupted microsomes of a protein band of slightly lower molecular mass than, and presumably derived from, the UGTs. However, a labeled cleavage product was found only in samples photolabeled with [32P]5N3UDP-GlcUA and not in those labeled with [32P]5N3UDP-Glc. In detergent-treated microsomes, all of the nucleotide sugars that were tested protected better against photoinsertion of [32P]5N3UDP-GlcUA than of [32P]5N3UDP-Glc, with UDP-glucose being the most effective, followed by UDP-GlcUA and UDP-galactose. The pattern of inhibition of a series of uridinyl analogs toward photolabeling by the two probes was quite different: one inhibitor that was ineffective in blocking photoincorporation of [32P]5N3UDP-GlcUA (L-DPASiU) was one of the most potent inhibitors of photolabeling with [32P]5N3UDP-Glc. A similar dichotomy was seen with several inhibitors in enzymatic assays measuring hyodeoxycholic acid 6-O glucuronidation and glucosidation activities; the most potent inhibitors of HDCA glucosidation were not as effective against glucuronidation. The results indicate a lumenal orientation for human microsomal UGTs and provide substantial evidence that two distinct enzyme systems are involved in 6-O glucuronidation and 6-O glucosidation of HDCA.

Characterization of a new class of inhibitors of the recombinant human liver UDP-glucuronosyltransferase, UGT1*6

The inhibitory effect of a series of novel structurally related compounds on the human UDP-glucuronosyltransferase UGT1*6 stably expressed in a V79 cell line was investigated. The inhibitors contain a lipophilic N-acyl phenylaminoalcohol residue and a uridine moiety connected by a spacer varying for each compound. The effects of these compounds on the glucuronidation reaction measured with 4-methylumbelliferone as substrate were determined. The best inhibitor of the series, D-DPMSU, had an IC50 of 39 microM in the assay conditions. Low Ki values were found toward both UDP-glucuronic acid and 4-methylumbelliferone (17 and 21 microM, respectively). The inhibition was competitive toward both substrates. A similar strong and competitive inhibitory effect was observed with two other inhibitors, DHPASU and DHPASiU. Another compound, D-DPASiU, showed a pure competitive inhibition towards UDP-glucuronic acid, but a non-competitive inhibition towards the acceptor substrate. These data and the optimization of the structures of the inhibitors by molecular modeling suggest that D-DPMSU and DHPASiU compounds may be transition state analog inhibitors of the recombinant UGT1*6 enzyme.

Membrane translocation and regulation of uridine diphosphate-glucuronic acid uptake in rat liver microsomal vesicles

BACKGROUND/AIMS

Hepatic glucuronidation is quantitatively the most important conjugation reaction by which an array of endogenous compounds and xenobiotics undergo biotransformation and detoxification. The active site of the uridine diphosphate (UDP) glucuronosyltransferases, which catalyze glucuronidation reactions, has been postulated to reside in the lumen of the endoplasmic reticulum. The aim of this study was to characterize the process whereby UDP glucuronic acid (UDP-GlcUA), the cosubstrate for all glucuronidation reactions, is transported into microsomal vesicles.

METHODS

The uptake process was analyzed using rapid filtration techniques, radiolabeled UDP-GlcUA, and rat liver microsomes.

RESULTS

Uptake was saturable with respect to time and concentration, inhibited by 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid and 4-acetamido-4'-isothio-cyanatostilbene-2-2'-disulfonic acid, and was osmotically sensitive. Transport was stimulated by Mg2+ and guanosine triphosphate (50 mumol/L) but not guanosine 5'-O-(3-thiotriphosphate) or adenosine triphosphate. Luminal UDP-N-acetylglucosamine (1 mmol/L) produced enhanced uptake of UDP-GlcUA (trans stimulation). In contrast to nucleotide sugar transport in the Golgi apparatus, trans uridine monophosphate and UDP did not alter UDP-GlcUA transport in microsomes, indicating distinct processes.

CONCLUSIONS

These data provide unambiguous evidence for the existence of a unique, substrate-specific, regulated, carrier-mediated process that transports UDP-GlcUA into the lumen of hepatocyte microsomes. This transporter may regulate glucuronidation in vivo.

Surveillance for sexually transmissible diseases in Victoria, 1983 to 1992

Surveillance systems have been developed in Victoria to determine trends in sexually transmissible diseases (STDs). Notifications to the Health Department (including laboratory notification since May 1990) have been supplemented by data about strains of Neisseria gonorrhoeae and cultures for Chlamydia trachomatis processed by the Microbiological Diagnostic Unit, enhanced laboratory surveillance of syphilis, and data on genital herpes and genital warts from the Melbourne Sexual Health Centre. During the period under review the incidence of gonorrhoea declined, rapidly at first, and then more slowly. For women, this trend has continued, while gonorrhoea acquired abroad by men has become relatively more important. Since 1988, gonorrhoea in homosexual men has increased, and rectal isolates have increased concurrently, raising concerns about HIV risk behaviour. Cases of syphilis are likely to be ascertained through STD, antenatal and refugee screening, rather than because of symptoms or contact tracing. Chlamydia is a the most common notifiable STD, despite underreporting and underdiagnosis. In 1991, 832 cases were notified, increasing to 1377 in 1992. In 1992, of the 73 cases (65 per cent of notifications) where the doctor identified a risk, 15 per cent was attributed to homosexual contact, and 27.4 per cent to heterosexual exposure. Limitations in the data include inadequate standard case definitions for many STDs, changes in the statutory requirement for notifications in 1990, underreporting, changes in diagnostic and screening patterns, and lack of detailed demographic data. Education of general practitioners is needed to improve diagnosis and notification of chlamydia.

Characterization of UDP-glucuronic acid transport in rat liver microsomal vesicles with photoaffinity analogs

The endoplasmic reticulum (ER) of rat liver contains several well characterized UDP-glucuronosyltransferases (UGTs), membrane-bound proteins of 50-54 kDa, and also less well identified UDP-glucosyltransferases, with nucleotide binding sites located on the lumenal surface. There is evidence that the substrates for these enzymes, UDP-glucuronic acid (UDP-GlcUA) and UDP-glucose (UDP-Glc), biosynthesized in the cytosol, are transported into the lumen of the ER via unknown mechanisms, the characteristics of which are poorly defined. A new approach for the study of the transport process has been devised using two active-site directed photoaffinity analogs, [beta-32P]5-azido-UDP-GlcUA and [beta-32P]5-azido-UDP-Glc. Photoincorporation of these probes into the lumenally oriented UGTs of intact rat liver microsomal vesicles was used as an indicator of transport. In intact vesicles, [32P]5N3UDP-GlcUA was efficiently incorporated into UGTs in a time, temperature and concentration dependent manner. In contrast, [32P]5N3UDP-Glc apparently was not transported effectively; maximal photolabeling of the 50-54 kDa proteins by this probe was dependent on detergent disruption of the vesicles. Vesicular uptake of and subsequent photolabeling of the 50-54 kDa proteins by [32P]5N3UDP-GlcUA were inhibited by UDP-GlcUA and 5N3UDP-GlcUA while UDP-Glc, 5N3UDP-Glc, UDP-xylose and UDP-N-acetylglucosamine were less inhibitory, suggesting a high degree of specificity for the uptake/photolabeling process. The anionic transport inhibitors DIDS and SITS inhibited [32P]5N3UDP-GlcUA photoincorporation into UGTs in intact vesicles, but also inhibited photolabeling of these and other enzymes in detergent disrupted vesicles. These data suggest the presence in rat liver microsomal vesicles of a specific, carrier-mediated transport process for UDP-GlcUA which is distinct from the mechanism of UDP-Glc transport.

Photoaffinity labeling for evaluation of uridinyl analogs as specific inhibitors of rat liver microsomal UDP-glucuronosyltransferases

The UDP-glucuronosyltransferases (UGT) involved in glucuronidation of endogenous and exogenous toxic compounds transfer the glucuronic acid residue from UDP-glucuronic acid (UDP-GlcUA), to various acceptor groups. A series of compounds that contain N-acyl phenylaminoalcohol derivatives linked to uridine or isopropylideneuridine were tested as UGT inhibitors. The potency of these inhibitors was determined by studying their effect on the photoaffinity labeling of rat liver microsomal UGTs by two photoaffinity probes, [beta-32P]5-azido-UDP-glucuronic acid (5N3UDP-GlcUA) and [beta-32P]5-azido-UDP-glucose (5N3UDP-Glc) and on the enzymatic formation of the two glucuronide conjugates (3-O- and carboxyl-specific) of lithocholic acid. All but one of the compounds tested proved to have an inhibitory effect on UGTs, both in the photoaffinity labeling system and in the enzymatic glucuronidation assay. In the photoaffinity labeling system, the inhibitors containing the isopropylidene moiety were less effective than their unprotected derivatives; however, the protected forms were, with one exception, more potent inhibitors of enzymatic activity. The photoaffinity labeling of UGTs with [beta-32P]5N3UDP-Glc was more susceptible to inhibition by all derivatives than that with [beta-32P]5N3UDP-GlcUA. The effect of one inhibitor, PP50B, on the two enzymatic activities involved in LA glucuronidation was extensively tested. A double-reciprocal plot suggested a competitive inhibition for UDP-GlcUA with an apparent Ki of 35 microM for LA 3-O-glucuronide formation and 94 microM for the carboxyl-linked glucuronide of the same substrate.

Bile acid glucuronidation by rat liver microsomes and cDNA-expressed UDP-glucuronosyltransferases

Four rat UDP-glucuronosyltransferases (UGTs), UGT2B1, UGT2B2, UGT2B3 and UGT2B6, synthesized in COS-7 cells from appropriate cDNA clones were screened for activity towards a range of bile acids, neutral steroids and retinoic acid. For comparison, as well as optimization of enzymatic assays and product identification, rat liver microsomal preparations from Sprague-Dawley, Fischer 344 and phenobarbital-induced Fischer 344 male rats were also used as enzyme sources. Only two of the expressed proteins, UGT2B1 and UGT2B2, were active in bile acid glucuronidation. UGT2B1 exhibited a high substrate specificity for the carboxyl function of bile acids, whereas UGT2B2 demonstrated less specificity, accepting both hydroxyl and carboxyl functions of bile acids. The preferred substrates for both cloned enzymes were mono-hydroxylated bile acids, followed by di-hydroxylated 6-OH compounds. The levels of UGT activity were sufficient to allow for the identification of the biosynthesized products. The data presented here demonstrate that bile acid glucuronidation is carried out, at least in part, by members of the UGT2B subfamily. Similar results have been obtained previously for neutral steroid glucuronidation. UGT2B3 and UGT2B6 was not involved in BA glucuronidation; none of the cloned enzymes was active toward retinoic acid.