Abstract 3139: Pan-cancer splicing analysis reveals shared drivers of malignant transformation and survival

Alternative splicing is one of the primary mechanisms used to achieve mRNA transcript and proteomic diversity in higher order eukaryotes. In cancer, altered mRNA splicing can lead to aberrant protein products that promote oncogenic transformation, metastasis and confer chemotherapy resistance, due to splicing factor mutation or mis-expression. We hypothesize that the role of splicing imbalance in cancer is grossly underestimated and is likely regulated by the same recurrent global disruptions observed across human cancers. To determine common and malignancy specific splicing subtypes across cancer we designed a novel integrated computational workflow that uses genome variant data from RNA-Seq in conjunction with fully unsupervised analyses (NMF and SVM) to identify novel patient splicing-defined subtypes (OncoSplice). Applied to 20 adult and pediatric cancers with large cohorts, we identified common-recurrent splicing subtypes associated with MYC-hyperactivation and TGF-beta signaling, lineage reprogramming, tumor infiltration and broad mutation impacts. Such recurrent and tumor specific subtypes were frequently associated with poor prognosis and novel dominantly regulated driving splicing events (e.g., transcription factors). Broad splicing subtypes were associated with circadian dysregulation, as determined from normal healthy tissues (GTEx) and in many cases were found to phenocopy well-described splicing mutation impacts or were associated with new RNA-binding proteins (RBPs) evidenced by orthogonal computational predictions. Splicing subtype associated RBPs were frequently undergo autoregulation, as further evidenced by CLIP-Seq and RBP knockdown. To enhance the RNA community’s ability to explore hundreds of known and novel splicing variation across cancers and healthy tissues, we provide an interactive online splicing explorer at oncosplice.org. Together, these data highlight previously unknown regulatory relationships and prognostic associations in cancer associated with broad and targeted splicing regulation.

Citation Format: Anukana Bhattacharjee, Audrey Crowther, Guangyuan Li, Meenakshi Venkatasubramanian, Dan Schnell, Stuart Hay, Preeti Singh, Krithika R. Subramanian, Kashish Chetal, Xiaoting Chen, Aishwarya Kulkarni, Matthew T. Weirauch, Nathan Salomonis. Pan-cancer splicing analysis reveals shared drivers of malignant transformation and survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3139.

The Perils of Riding Motocross: A Summary of this Extensive, Prospective Study

Background

Motocross is a high-risk form of motorbiking where serious injuries occur regularly, although little data have been collected to illustrate this relationship. Over 5 years, teams from RJAH Oswestry and RSH sought to demonstrate the impact of Motocross on orthopaedic presentation and workload.

Method

Data were collected prospectively over 5 years including 615 orthopaedic injuries associated with both recreational and competitive motocross.

Results

An increase in injury and operation frequency was observed, young males were identified as the highest risk participant. This was evident over winter and weekends, during the competitive racing season. A variety of injuries have been implicated, some with life threatening or disabling consequences.

Conclusion

Motocross has seen exponential growth in popularity with increases in injuries and operations. This implicates major impacts on finances and healthcare, especially at times of seasonal vulnerability. The authors encourage event organisers to explore the avenues of rider safety in this increasingly popular sport.

Developmental dynamics and genomic programming of GC-derived precursors that give rise to long lived plasma cells

Plasma cell (PC) precursors are generated during a germinal center (GC) response and migrate to the bone marrow (BM) where they undergo terminal differentiation into short-lived (SL) or long-lived (LL) antibody secreting cells. The developmental dynamics and genomic states of PC precursors remain to be elucidated1. We utilize a novel experimental system, involving CD138+ splenocytes isolated from NP-KLH immunized C57Bl/6J mice (21–42 dpi) and their adoptive transfer into B cell deficient mMT mice, to analyze developmental dynamics of antigen-specific PC precursors and their progeny at single-cell resolution. We demonstrate that SLPC precursors are generated earlier (d21), whilst LLPC precursors are generated later (d35) during a GC response. scRNA-seq analyses reveals increased frequency of a novel cluster of transitional cells expressing both B-lineage and plasma cell-specific genes. Coupled analyses using BCR-seq shows that NP-specific transitional cells express cell cycle genes and undergo greater clonal expansion on d35 to give rise to proliferating and quiescent PCs. Antigen-specific clonal tracking in the spleen and BM compartments suggests that the transitional cells emanating from the GC, differentiate into proliferating PCs before migrating to the BM. CITE-seq analyses and reconstitution experiments demonstrate that proliferating PCs are contained within the B220− CD138+ CD44+ CD11a+ subset and are enriched for BMPC precursors. These results reveal novel GC-derived transitional cells that generate precursors of both SLPCs and LLPCs with differing developmental and proliferation dynamics in a humoral immune response.

42 An Analysis of Virtual Fracture Clinics in Orthopaedic Trauma in the UK During the Coronavirus Crisis

Aim

Virtual Fracture Clinics (VFC) are advocated by new Orthopaedic (British Orthopaedic Association) and National Health Service (NHS) guidelines in the United Kingdom. We discuss benefits and limitations, reviewing the literature. As well as recommendations on introducing a VFC service during the Coronavirus pandemic and into the future.

Method

A narrative review identifying current literature on virtual fracture clinic outcomes when compared to traditional model fracture clinics in the UK. We identify 9 relevant publications related to VFC.

Results

The Glasgow Model initiated in 2011 has become the benchmark. Clinical efficiency can be improved, reducing the number of ED referrals seen in VFC by 15%-28% and face to face consultations by 65%. 33-60% of patients may be discharged after review in the VFC. Some studies have shown no negative impact on the Emergency Department (ED), the time to discharge was not increased. Patients satisfaction ranges from 91%-97% using a VFC service, and there may be cost saving benefits annually from £67,385-£212,705. Non-attendance may be reduced by 75% and there are educational opportunities for trainees. However, evidence is limited, 28% of patients prefer face-to-face consultations and not all have access to internet or email (72%).

Conclusions

We propose a pathway integrating the VFC model, whilst having Senior Orthopaedic decision makers available in ED, during normal working hours, to cope with the pandemic. Beyond the pandemic, evidence suggests the Glasgow model is viable for day-to-day practice.

An analysis of virtual fracture clinics in orthopaedic trauma in the UK during the coronavirus crisis

Virtual fracture clinics (VFC) are advocated by new orthopaedic (British Orthopaedic Association) and National Health Service (NHS) guidelines in the United Kingdom. We discuss benefits and limitations, reviewing the literature, as well as recommendations on introducing a VFC service during the coronavirus pandemic and into the future.A narrative review identifying current literature on virtual fracture clinic outcomes when compared to traditional model fracture clinics in the UK. We identify nine relevant publications related to VFC.The Glasgow model, initiated in 2011, has become the benchmark. Clinical efficiency can be improved, reducing the number of emergency department (ED) referrals seen in VFC by 15-28% and face-to-face consultations by 65%. After review in the VFC, 33-60% of patients may be discharged. Some studies have shown no negative impact on the ED; the time to discharge was not increased. Patient satisfaction ranges from 91-97% using a VFC service, and there may be cost-saving benefits annually of £67,385 to £212,705. Non-attendance may be reduced by 75% and there are educational opportunities for trainees. However, evidence is limited; 28% of patients prefer face-to-face consultations and not all have access to internet or email (72%).We propose a pathway integrating the VFC model, whilst having senior orthopaedic decision makers available in the ED, during normal working hours, to cope with the pandemic. Beyond the pandemic, evidence suggests the Glasgow model is viable for day-to-day practice. Cite this article: EFORT Open Rev 2020;5:442-448. DOI: 10.1302/2058-5241.5.200041.

cellHarmony: cell-level matching and holistic comparison of single-cell transcriptomes

To understand the molecular pathogenesis of human disease, precision analyses to define alterations within and between disease-associated cell populations are desperately needed. Single-cell genomics represents an ideal platform to enable the identification and comparison of normal and diseased transcriptional cell populations. We created cellHarmony, an integrated solution for the unsupervised analysis, classification, and comparison of cell types from diverse single-cell RNA-Seq datasets. cellHarmony efficiently and accurately matches single-cell transcriptomes using a community-clustering and alignment strategy to compute differences in cell-type specific gene expression over potentially dozens of cell populations. Such transcriptional differences are used to automatically identify distinct and shared gene programs among cell-types and identify impacted pathways and transcriptional regulatory networks to understand the impact of perturbations at a systems level. cellHarmony is implemented as a python package and as an integrated workflow within the software AltAnalyze. We demonstrate that cellHarmony has improved or equivalent performance to alternative label projection methods, is able to identify the likely cellular origins of malignant states, stratify patients into clinical disease subtypes from identified gene programs, resolve discrete disease networks impacting specific cell-types, and illuminate therapeutic mechanisms. Thus, this approach holds tremendous promise in revealing the molecular and cellular origins of complex disease.

Hand and Wrist Injuries Related to Motocross Injuries: 5 Year Series

Background: The increasingly fashionable sport of motocross is practiced worldwide by millions of people, but there is very little in the literature regarding its associated injuries and their prevention. We therefore present the first comprehensive, prospective study looking at hand and wrist injuries resulting from motocross injuries in the UK.

Methods: Data was prospectively collected over a 5-year period (from 2010 to 2015) at our regional trauma unit. We exclusively looked at motocross riders. Injuries sustained via motorcycle were excluded from our study.

Results: During the period studied (five years), 615 injuries were collected, including 240 patients with 265 hand and wrist injuries. Most of injuries were sustained in male patients. The patient’s age range was from 4–78 years with most injuries occurring during the spring and summer months. A total of 96 (40%) patients required operative treatment. The most common injury pattern was distal radius fractures (n = 53, 20%), followed by metacarpal fractures (n = 38, 14%) and phalangeal fractures (n = 36, 13.5%).

Conclusions: This study shows the impact and incidence of related hand and wrist injuries. Motocross is a globally fashionable sport. This study shows that the number of annual tournaments and racers have doubled in last 5 years. The number of hand and wrist related injuries and operative requirements have quadruples over the last five years. It is recognized as a high-risk sport despite the use of protective equipment and course adaptions. These injuries can have implications for nearby treating hospitals.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

The Provision of Primary and Revision Elbow Replacement Surgery in the NHS

BESS Surgical Procedure Guidelines (SPGs). Optimising Surgical Outcomes for Shoulder and Elbow patients. The British Elbow and Shoulder Society (BESS) SPGs are a series of evidence and consensus Best Practice Recommendations developed by BESS surgeons and physiotherapists to help drive quality improvement and achieve the best possible surgical outcomes for UK patients. This SPG on primary and revision elbow replacement surgery is supported and endorsed by both the British Orthopaedic Association (BOA) and the Getting It Right First Time (GIRFT) Programme.

Revision shoulder arthroplasty for failed surface replacement hemiarthroplasty

PURPOSE

The aim of this study was to assess the reasons of failure of shoulder surface replacement hemiarthroplasty (SRH) and to evaluate the outcome of revision surgery.

METHOD

The study group included 25 patients (26 shoulders) with failed SRHs. The mean time to revision surgery was 3.6 years. Their functional outcome was evaluated using adjusted Constant-Murley score at mean follow-up of 5.2 years (range 2-16 years).

RESULT

Most common cause of failure was glenoid erosion (42%) and progressive failure of rotator cuff (31%). Median adjusted Constant-Murley score at mean follow-up of 5.2 years was 51.6. Median adjusted Constant-Murley score in patients who had primary diagnosis of osteoarthritis and had revision performed to anatomic TSA (14 shoulders) was 85 (range 40-100) at mean follow-up of 5 years compared to 36.3 (range 20-66.3) in the remaining patients at 5.4 years, p = 0.00008.

CONCLUSION

Revision surgery for failed SRH can be technically challenging with variable results. Most common mode of failure was glenoid erosion. Functional outcomes are better in those with revision performed to anatomic TSA.

Spinal Motocross Injuries in the United Kingdom

Background

Motocross is a form of motorcycle racing held on established off-road circuits and has been a recreational and competitive sport across the world for >100 years. In the United Kingdom alone, motocross has grown into a phenomenally ambitious and popular franchise. There are >200 motocross clubs across the country, permitting >900 events annually.

Purpose

To assess the current trend of spine-related motocross injuries over the past 5 years.

Study Design

Descriptive epidemiology study.

Methods

Data were prospectively collected over 5 years (August 2010-August 2015) at our regional trauma and spine unit, regardless of whether the rider was performing the sport competitively or recreationally.

Results

During the study period, spine-related injuries were identified for 174 patients (age range, 6-75 years) who were directly referred to our department following recreational or competitive motocross, with most injuries being sustained within the early spring and summer months, representing the start of the motocross season. A significant number of injuries were in males (n = 203, 94%), with the majority of injuries occurring within the 21- to 30-year-old age group. A total of 116 (54%) injuries required operative treatment. The most common spinal injury was thoracolumbar burst fracture (n = 95), followed by chance fractures (n = 26).

Conclusion

This data series emphasizes the prevalence and devastation of motocross-related spinal injuries in the United Kingdom and may serve in administering sanctions and guidelines to governing bodies of motocross. The spinal injuries that occur during motocross have significant capital connotations for regional spinal centers. The recent surge in motocross popularity is correlated with the number of injuries, which have increased over the past 5 years by almost 500%.

A Study To Assess The Prevalence Of Exercise-Induced Bronchoconstriction In Inter-County Hurling

Exercise-Induced Bronchoconstriction (EIB) is an acute, transient airway narrowing occurring after exercise which may impact athletic performance. Studies report 10% of the general population and up to 90% of asthmatics experience EIB. Ninety-two players from three elite hurling squads underwent a spirometric field-based provocation test with real-time heart rate monitoring and lactate measurements to ensure adequate exertion. Players with a new diagnosis of EIB and those with a negative field-test but with a previous label of EIB or asthma underwent further reversibility testing and if negative, methacholine challenge. Eight (8.7%) of players had EIB, with one further athlete having asthma with a negative field test. Interestingly, only three out of 12 players who had previously been physician-labelled with EIB or asthma had their diagnosis objectively confirmed. Our study highlights the role of objective testing in EIB.

Unusual lesions mimicking impingement syndrome in the shoulder joint - Think medially

Impingement syndrome is usually caused by irritation of the rotator cuff within the sub acromial space and this includes the coraco-acromial arch (Acromion and Coraco-acromial ligament), the acromio-clavicular joint and occasionally the coracoid. Iatrogenic causes such as sutures, pins, plates or wires left from previous surgery can cause similar symptoms. We present a series of four cases mimicking “classical” impingement symptoms/signs in which the causal pathology was identified outside the sub-acromial space. Magnetic Resonance Imaging (MRI) showed lesions that were present in the supra-spinatus fossa but were causing pressure effects on the sub-acromial space, namely - a ganglion cyst in one case, lipomata in two other cases, and a glomus tumour. A ganglion cyst and glomus tumour mimicking impingement syndrome is a rare reported case to our knowledge.

These are unusual causes that should be considered when investigating classical impingement syndrome and particularly those who may have failed to respond to decompression surgery. They highlight the potential value of looking beyond the sub-acromial space for causal lesions and in these cases, at a time when limited ultrasound investigation has become increasingly popular; MRI has clearly played an important and was essential in planning surgery as these lesions would not have been identified on USS. Even though the symptoms were classical.

•

Impingement syndrome is defined as impingement of the rotator cuff by the anterior one-third of the acromion, 1.

•

Iatrogenic causes such as sutures, can cause similar symptoms.

•

Symptoms and signs of impingement may be present can originate outside the sub-acromial space.

•

MRI scan remains an important imaging tool.

Motocross biking for competition and for recreation: a prospective analysis of 423 injured riders

Background

Motocross is a form of motorcycle racing held on established off-road circuits and has been a recreational and competitive sport across the world for over 100 years. In the UK alone, motocross has grown into a phenomenally ambitious and popular franchise. There are over 200 motocross clubs across the country, permitting over 900 events annually.

Method

Data were collected prospectively over 4 years (from 2010 to 2014) at our unit. All injuries caused by motocross biking that were referred to our trauma and orthopaedic department were included in this study, regardless of whether the rider was performing the sport competitively or recreationally.

Results

During the period studied (4 years), 423 patients were included with a total of 485 injuries, ranging from 1 to 6 injuries per patient. The patient's age range was from 4 to 73 years, with most of the injuries being sustained within the early spring and summer months representing the start of the motocross season.

Conclusions

We present the first epidemiological study of motocross injuries in the UK. Within the growing culture of ‘adrenaline sports’, motocross has become an exhilarating and extremely fashionable pastime. This study has identified and categorised the spectrum of injuries from upper limb fracture dislocations to life-threatening head and chest injuries, some of which are serious and may cause significant morbidity and possible mortality. These injuries could have significant resource implications, especially for smaller rural hospitals.

An epidemiological study of paediatric motocross injuries in the United Kingdom

PURPOSE

Although off-road motorcycling is one of the most popular sports activities practised by millions of people worldwide, little has been written on motocross injuries and their prevention. In the UK alone, motocross has grown into a phenomenally ambitious and popular franchise. There are >200 motocross clubs across the country holding >900 events annually. The aim of this study is to categorise and quantify the magnitude of motocross paediatric injuries and associated morbidity.

METHODS

Data were collected prospectively over 4 years (2010-2014) at our unit. All injuries caused by motocross biking that were referred to our trauma and orthopaedic department were included in this study, regardless of whether the rider was performing the sport competitively or recreationally.

RESULTS

During the study period, 130 patients (aged 4-17 years) were identified with a total of 142 injuries, ranging from one to six injuries per patient. Most of the injuries were sustained within the early spring and summer months, representing the start of the motocross season; 76 patients required hospital admission, with 60 (42 %) requiring surgical intervention.

CONCLUSION

We present the first epidemiological study of motocross paediatric injuries in the UK. The results from this study highlight the frequency and severity of motocross-related injuries in the paediatric population in the UK. This may assist in providing recommendations and guidelines to governing bodies and to parents. The injuries sustained during motocross have significant resource implications, especially for smaller rural hospitals, as shown by the number of injuries doubling over the past 4 years.

Sensitivity of fresh isolates of soft tissue sarcoma, osteosarcoma and giant cell tumour cells to Apo2L/TRAIL and doxorubicin

Chemotherapy is an established treatment modality for bone sarcomas such as osteosarcoma (OS). However, the use of chemotherapy in high-grade soft tissue sarcomas remains controversial, with the most active chemotherapeutic agent, doxorubicin (DOX), reported to have a response rate of, at best only 34% and most studies reporting lower response rates. Apo2L/TRAIL is a member of the tumour necrosis factor (TNF) family of cytokines and induces death of tumour cells, but not normal cells. Its potent apoptotic activity is mediated through cell surface death domain-containing receptors, DR4/TRAIL-R1 and DR5/TRAIL-R2. We investigated the efficacy of Apo2L/TRAIL as a single agent, and in combination with clinically relevant chemotherapeutic drugs, in fresh isolates of primary malignant cells obtained from biopsy material. The data presented here demonstrate that, in a range of primary bone related tumours, as well as soft tissue sarcomas, chemotherapeutic agents were only moderately effective, in terms of induction of cell death. Apo2L/TRAIL alone had little or no effect on any bone-related tumour or sarcoma in culture. In contrast, the combination of Apo2L/TRAIL and chemotherapeutic drugs produced a significant increase in tumour cell death, with DOX and Apo2L/TRAIL proving to be the most effective combination. These data suggest the potential for Apo2L/TRAIL to increase the effectiveness of chemotherapeutic drugs in bone and soft tissue sarcomas, while perhaps concurrently allowing a reduction in the exposure to drugs such as DOX, and a consequent reduction in toxicity. The synergistic action between these two different classes of agents has yet to be tested in vivo but may prove clinically relevant in the treatment of this refractive class of malignancies.

Induction of cell death of human osteogenic sarcoma cells by zoledronic acid resembles anoikis

The aim of this study was to investigate the cytotoxic activity of the third-generation nitrogen-containing bisphosphonate zoledronic acid (ZOL) as a single agent, and in combination with clinically relevant anticancer drugs, in a panel of human osteogenic sarcoma cell lines (HOS, BTK-143, MG-63, SJSA-1, G-292, and SAOS2). We found that ZOL, when used alone, reduced cell number in a dose- and time-dependent manner, due either to cell cycle arrest in S-phase or to the induction of apoptosis. In the sensitive HOS, BTK-143, and G-292 cell lines, genomic DNA fragmentation and morphological changes characteristic of apoptosis were evident, and cells became nonadherent. Induction of apoptosis in osteosarcoma cells by ZOL was associated with caspase activation. However, coaddition of the broad-spectrum caspase inhibitors, z-VAD-fmk, Boc-D-fmk, or the caspase-3-specific inhibitor z-DEVD fmk, failed to protect these cells from ZOL-induced apoptosis. Our data support a ZOL-specific induction of cell apoptosis that involves cell detachment (anoikis), and in which caspase activation occurs secondarily to, and is redundant as a mediator of cell death. The addition of geranylgeraniol, an intermediate of the mevalonate pathway, suppressed the ZOL-induced apoptosis, suggesting that the cytotoxic effects of ZOL in osteosarcoma cells were mediated by the mevalonate pathway. While treatment of osteosarcoma cells with the chemotherapeutic agents doxorubicin or etoposide decreased cell viability, combination of these agents with ZOL did not significantly augment apoptosis in any of the cell lines tested. These observations suggest that ZOL has direct effects on the proliferation and survival of osteosarcoma cells in vitro, which has implications for future therapy of osteosarcoma.

Progressive resistance of BTK-143 osteosarcoma cells to Apo2L/TRAIL-induced apoptosis is mediated by acquisition of DcR2/TRAIL-R4 expression: resensitisation with chemotherapy

Apo2 ligand (Apo2L, also known as TRAIL) is a member of the tumour necrosis factor (TNF) family of cytokines that selectively induces the death of cancer cells, but not of normal cells. We observed that recombinant Apo2L/TRAIL was proapoptotic in early-passage BTK-143 osteogenic sarcoma cells, inducing 80% cell death during a 24 h treatment period. Apo2L/TRAIL-induced apoptosis was blocked by caspase inhibition. With increasing passage in culture, BTK-143 cells became progressively resistant to the apoptotic effects of Apo2L/TRAIL. RNA and flow cytometric analysis demonstrated that resistance to Apo2L/TRAIL was paralleled by progressive acquisition of the decoy receptor, DcR2. Blocking of DcR2 function with a specific anti-DcR2 antibody restored sensitivity to Apo2L/TRAIL in a dose-dependent manner. Importantly, treatment of resistant cells with the chemotherapeutic agents doxorubicin, cisplatin and etoposide reversed the resistance to Apo2L/TRAIL, which was associated with drug-induced upregulation of mRNA encoding the death receptors DR4 and DR5. BTK-143 cells thus represent a useful model system to investigate both the mechanisms of acquisition of resistance of tumour cells to Apo2L/TRAIL and the use of conventional drugs and novel agents to overcome resistance to Apo2L/TRAIL.

Calcitonin decreases the adherence and survival of HEK-293 cells by a caspase-independent mechanism

We recently reported that calcitonin (CT) can profoundly inhibit the growth of HEK-293 cells transfected with the human calcitonin receptor (hCTR). We also obtained preliminary evidence that suggested a role for CT in cell survival, and in the present study we have investigated the pro-apoptotic action of CT, which we observe in conditions of low serum concentration. Under these conditions, we have found that CT treatment of HEK-293 cells stably transfected with the insert-negative form of the human CTR (HR12 cells) caused a time-dependent decrease in cell number associated with loss of cellular attachment. Loss of cellular adherence in CT-treated cultures caused programmed cell death, as shown by Annexin V staining of cells, failure of cells to exclude Trypan Blue dye, condensation and cleavage of nuclear DNA, and appearance of hypodiploid cells in fluorescence-activated cell sorting (FACS) analysis. The accumulation of non-adherent cells and cell death was concomitant with increased intracellular activity of caspase-3. However, inhibition of caspase activation in HR12 cells did not prevent CT-mediated loss of attachment and did not maintain the viability of non-adherent cells, indicating that caspase activation accompanied, but was probably not the cause of, the loss of cell viability. Neither the effects of CT on cell survival nor the activation of caspase-3 were observed in serum-replete conditions, suggesting that serum-derived factors provide protection of cells from CT-induced apoptosis. The inhibitory effects of CT on cell growth were found previously to be related to activation of Erk1/2 MAP kinase. In the present experiments, it was found that the Erk1/2 inhibitor, PD 98059, inhibited the CT-induced loss of cellular adherence and the consequent reduction in cell numbers. These results demonstrate that CT can negatively affect cell survival and they identify roles for cell adherence and MAP kinase activation in this process.

Human osteoblasts are resistant to Apo2L/TRAIL-mediated apoptosis

Apo2 ligand (Apo2L/TRAIL) is a member of the tumor necrosis factor (TNF) cytokine family. Apo2L/TRAIL can selectively induce programmed cell death in transformed cells, although its wide tissue distribution suggests potential physiological roles. We have investigated the expression, in human osteoblast-like cells (NHBC), of Apo2L/TRAIL and the known Apo2L/TRAIL death receptors, DR4 and DR5, and the Apo2L/TRAIL decoy receptors, DcR-1, DcR-2, and osteoprotegerin (OPG). NHBC expressed abundant mRNA corresponding to each of these molecular species. Immunofluorescence staining demonstrated that Apo2L/TRAIL protein was abundant within the cytoplasm of NHBC and OPG was strongly expressed at the cell surface. DR5 and DcR-2 were present in the cell membrane and cytoplasm and DcR-1 was confined to the nucleus. DR4 staining was weak. Neither Apo2L/TRAIL alone, nor in combination with chemotherapeutic agents of clinical relevance to treatment of osteogenic sarcoma, induced cell death in NHBC, as assessed morphologically and by activation of caspase-3. In contrast, the human osteogenic sarcoma cell lines, BTK-143 and G-292, were sensitive to exogenous Apo2L/TRAIL alone, and to the combined effect of Apo2L/TRAIL/cisplatin and Apo2L/TRAIL/doxorubicin treatments, respectively. In NHBC, we observed strong associations between the levels of mRNA corresponding to the pro-apoptotic molecules, Apo2L/TRAIL, DR4, and DR5, and those corresponding to pro-survival molecules, DcR-1, DcR-2, OPG, and FLIP, suggesting that the balance between pro-survival and pro-apoptotic molecules is a mechanism by which NHBC can resist Apo2L/TRAIL-mediated apoptosis. In contrast, osteogenic sarcoma cells had low or absent levels of DcR-1 and DcR-2. These results provide a foundation to explore the role of Apo2L/TRAIL in osteoblast physiology. In addition, they predict that therapeutic use of recombinant Apo2L/TRAIL, in combination with chemotherapeutic agents to treat skeletal malignancies, would have limited toxic effects on normal osteoblastic cells.

Enhanced apoptosis of soft tissue sarcoma cells with chemotherapy: A potential new approach using TRAIL

Soft tissue sarcomas are less responsive to conventional chemotherapy when compared to bone sarcomas. We investigated the possibility of enhancing the efficacy of chemotherapy by utilising the recently identified cytokine, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) in combination with standard chemotherapeutic agents. Fresh human soft tissue sarcomas (rhabdomyosarcoma, fibrosarcoma, malignant fibrous histiocytoma) were obtained at biopsy and dispersed tumour cells were incubated in cell culture with standard cytotoxic agents, either as single agents or in combination with TRAIL. The chemotherapeutic agents were, at best, moderately effective, in terms of induction of cellular apoptosis, although the fibrosarcoma was completely unresponsive to all single agents. TRAIL alone had no effect on any sarcoma cell culture. In contrast, the addition of TRAIL and drug together produced a significant increase in sarcoma cell apoptosis, with TRAIL and doxorubicin the most effective combination.

Expression of alternatively-spliced MDM2 transcripts in giant cell tumours of bone

Giant cell tumours of bone (GCT) are characterized histologically by multinucleated bone resorbing giant cells in a background of ovoid spindle-shaped mesenchymal cells. Current evidence suggests that the latter comprise the tumour element of these lesions, although there are basic questions as to the factors that contribute to the tumourigenesis and progression of GCT. The deregulation of the p53/MDM2 pathway is an important pathogenetic event in many tumour types, prompting us to assess the expression of MDM2 by the stromal cells and giant cells of GCT. Northern blot analysis demonstrated that most of the GCT samples examined expressed increased levels of MDM2 when compared to normal human bone cells. However, Southern analysis failed to show any evidence of MDM2 gene amplification in the same samples, suggesting that increased levels of MDM2 mRNA were not a direct result of gene amplification, but rather due to altered transcriptional regulation of MDM2 gene. By RT-PCR analysis we found that 7/8 giant cell tumours expressed strongly a short alternatively spliced variant of MDM2, whereas other tumours of bone and normal human bone cells expressed predominantly full length MDM2. Sequence analysis confirmed this variant to be MDM2-b, a variant previously reported to confer a transformed phenotype. Cell fractionation of the GCTs has shown that the MDM2-b splice variant was expressed exclusively in the stromal population, whereas the full length MDM2 was expressed in the multinucleated giant cells of these lesions. Overexpression of a green fluorescent protein-tagged MDM2-b in human embryonic kidney cells (HEK-293), demonstrated predominantly nuclear localisation. Immunoprecipitation studies showed that MDM2-b is unable to physically associate with the p53 tumour suppressor protein. These results are consistent with the hypothesis that the stromal cells comprise the tumour element in giant cell tumours of bone and we speculate that expression of the MDM2-b splice variant contributes to their transformed phenotype in a p53 independent manner.

Osteoprotegerin inhibits osteoclast formation and bone resorbing activity in giant cell tumors of bone

Osteolysis is a common complication of tumors that arise in, or metastasize to, bone. The recent discovery of key regulators of osteoclast formation and activity, including receptor activator of nuclear factor of kappaB ligand (RANKL), RANK, and osteoprotegerin (OPG), may facilitate new treatment regimes for certain tumors associated with excessive bone loss. We recently showed that the stromal cells of osteolytic giant cell tumors (GCT) of bone express high levels of mRNA encoding RANKL, relative to mRNA for the RANKL antagonist, OPG, compared with the expression patterns of other lytic and nonlytic bone tumors. In this study, we found that expression of RANKL and OPG mRNA continued by the stromal element of these tumors in a constitutive manner for at least 9 days in the absence of giant cells. Immunostaining of unfractionated GCT cultured in vitro revealed punctate cytoplasmic/membranous staining for RANKL and both cytoplasmic and extracellular matrix staining for OPG in stromal cells. Giant cells (osteoclasts) were negative for RANKL staining, but stained brightly for cytoplasmic OPG protein. We also investigated the functional relevance of these molecules for GCT osteolysis by adding recombinant OPG and RANKL to cultured GCT cells. We found that OPG treatment potently and dose-dependently inhibited resorption of bone slices by GCT, and could also inhibit the formation of multinucleated osteoclasts from precursors within the GCT. These effects of OPG were reversed by stoichiometric concentrations of exogenous RANKL. These data indicate that both the processes of osteoclast formation and activation in GCT are promoted by RANKL. Therefore, GCT represent a paradigm for the direct stimulation of osteoclast formation and activity by tumor stromal cells, in contrast to the mechanisms described for osteolytic breast tumors and multiple myeloma. The demonstration of these relationships is important in developing approaches to limit tumor-induced osteolysis.

Expression of fibrillins and other microfibril-associated proteins in human bone and osteoblast-like cells

Fibrillin-containing microfibrils are structural components of extracellular matrices of a diverse range of tissues, including bone. Their importance in bone biology is illustrated by the skeletal abnormalities manifest in the congenital disorder, Marfan syndrome, which results from mutations in the fibrillin-1 gene. We investigated the expression of fibrillins and other microfibril-associated proteins in human bone and bone-derived osteoblasts. Analysis of RNA extracted from cancellous bone showed expression of mRNAs encoding fibrillin-1 and -2, MAGP-1 and -2, LTBP-2, and MP78/70 (Big-h3). In demineralized normal mature bone, fibrillin-1 was immunolocalized to fibrils within the bone matrix and pericellularly to cells lining the endosteal surfaces of trabecular bone, some osteocytes, and cells associated with blood vessels. LTBP-2 was also identified at the endosteal surface and within the bone matrix in a lamellar fashion. In addition, primary osteoblast-like cells cultured from human trabecular bone (obtained from patients at joint replacement surgery) were found to express abundant mRNA for fibrillins and associated glycoproteins. Moreover, using western blot analysis, fibrillin-1 protein was shown to be secreted into the medium and to be deposited into the cell layer. Immunofluorescence staining of the cell layer visualized fibrillin-1 in the matrix as a three-dimensional network of fine filaments. Expression of fibrillin-1 by osteoblast-like cells was constitutive, and a number of skeletally active agents had little effect on mRNA or protein levels. These results show that human osteoblasts from mature bone express fibrillins and other microfibril-associated proteins, and suggest a role for these molecules in adult human bone.

Expression of osteoclast differentiation signals by stromal elements of giant cell tumors

The mechanisms by which primary tumors of the bone cause bone destruction have not been elucidated. Unlike most other lytic bone tumors, osteoclastomas, otherwise known as giant cell tumors (GCT), contain osteoclast-like cells within the tumor stroma. A new member of the TNF-ligand superfamily member, osteoclast differentiation factor (ODF/OPGL/RANKL/TRANCE), was recently identified. ODF was shown to directly stimulate osteoclastogenesis, in the presence of M-CSF. In this study, the expression of ODF was examined in a number of tumor samples associated with bone lysis in vivo. In addition, we investigated expression of the ODF receptor on osteoclast precursors, RANK, as well as the ODF inhibitor osteoprotegerin (OPG), and another TNF-ligand superfamily member, TRAIL, previously shown to abrogate the inhibitory effects of OPG. We report here the novel finding that GCT stromal cells contain abundant ODF mRNA, whereas the giant cell population exclusively expresses RANK mRNA. These results are consistent with the osteoclast-mediated bone destruction by these tumors. We also report the expression of OPG and TRAIL mRNA in GCT samples. A comparison with other lytic and nonlytic tumors of bone showed that GCT express more ODF and TRAIL mRNA relative to OPG mRNA. In addition, GCT were found to express a number of cytokines previously reported to play central roles in osteoclastogenesis, namely, IL-1, -6, -11, -17, as well as TNF-alpha. Importantly, GCT were also found to express high levels of M-CSF mRNA, a cytokine shown to be an essential cofactor of ODF, and a survival factor for mature and developing osteoclasts. Furthermore, expression of these molecules by stromal cells isolated from GCT continued in vitro. Thus GCT constitutively express all of the signals that are currently understood to be necessary for the differentiation of osteoclasts from precursor cells.

Condom promotion in women attending inner city general practices for cervical smears: a randomized controlled trial

BACKGROUND

Although condom promotion schemes have been widely piloted in UK general practices, there have been no rigorous evaluations of their effectiveness.

OBJECTIVES

To see if a practice-based sexual health education intervention increases the number of women having smears who are given condoms and advice on avoiding STDs. To see if this low cost intervention affects subsequent condom use.

METHOD

We conducted a cluster randomized trial of condom promotion in 1382 women aged <35 years attending 28 South London general practices for cervical smear tests.

RESULTS

More women in intervention than control practices reported receiving advice on avoiding sexually transmitted infections (27% versus 10%) and being given condoms (28% versus 1%, P < 0.05). However, there was no difference in subsequent condom use, even in the 22% of women reporting >/=2 sexual partners in the previous year.

CONCLUSIONS

To provide evidence of effectiveness, future interventions may need to be more intensive or focus on higher risk groups.

Sexual lifestyle of women attending inner-city general practices for cervical smears

Despite high prevalences of sexually transmitted infections, little is known about the sexual lifestyles of women attending inner-city general practices. Responses from a 1996 questionnaire showed that age at first intercourse and numbers of sexual partners were similar to the national survey five years earlier. However, only 49% of women reporting > or = 2 sexual partners in the past year said their partner had used a condom at the last sexual intercourse.

Integrin expression and function on human osteoblast-like cells

The integrin family of cell adhesion molecules are a series of cell surface glycoproteins that recognize a range of cell surface and extracellular matrix (ECM)-associated ligands. To date, the precise role of individual integrin molecules in bone cell-ECM interactions remains unclear. Cell binding assays were performed to examine the ability of normal human bone cells (NHBCs) to adhere to different ECM proteins in vitro. NHBCs displayed preferential adhesion to fibronectin over collagen types I, IV, and vitronectin and showed low affinity binding to laminin and collagen type V. No binding was observed to collagen type III. The integrin heterodimers alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha v beta 3, and alpha v beta 5 were found to be constitutively expressed on the cell surface of NHBCs by flow cytometric analysis. The integrins alpha 4 beta 1 and alpha 6 beta 1 were not expressed by NHBCs. Subsequent binding studies showed that NHBC adhesion to collagen and laminin was mediated by multiple integrins where cell attachment was almost completely inhibited in the presence of a combination of function-blocking monoclonal antibodies (Mabs) to alpha 1 beta 1, alpha 2 beta 1, alpha 3 beta 1, and beta 1. In contrast, the adhesion of NHBCs to fibronectin was only partially inhibited (50%) in the presence of blocking Mabs to alpha 3 beta 1, alpha 5 beta 1, and beta 1. The attachment of NHBCs to collagen, laminin, fibronectin, and vitronectin was also found to be unaffected in the presence of a function-blocking Mab to alpha v beta 3. The results of this study indicate that beta 1 integrins appear to be the predominant adhesion receptor subfamily utilized by human osteoblast-like cells to adhere to collagen and laminin and in part to fibronectin.

Technical basis for EPA's proposed regulation on the cleanup of sites contaminated with radioactivity

The U.S. Environmental Protection Agency is proposing a regulation for the protection of the public from radioactive contamination at sites that are to be cleaned up and released for public use. The rule will apply to sites under the control of Federal agencies, and will impose limits on radiation doses to individuals living or working on a site following cleanup; it will thereby provide site owners and managers with uniform, consistent cleanup criteria for planning and carrying out remediation. This paper presents an overview of EPA's approach to assessing some of the beneficial and adverse effects associated with various possible values for the annual dose limit. In particular, it discusses the method developed to determine how the choice of cleanup criterion affects (1) the time-integrated potential numbers of non-fatal and fatal radiogenic cancers averted among future populations, (2) the occurrence of radiogenic cancers among remediation workers and the public caused by the cleanup process itself, and (3) the volumes of contaminated soil that may require remediation. The analytic methods described here were used to provide input data and assumptions for the Regulatory Impact Analysis (RIA) that supports the proposed regulation; the RIA also considered non-radiological benefits and costs (i.e., public health, economic, and ecological) of the standards.

The synovial response to intraarticular injection in rats of polyethylene wear particles

To study the effect on tissues of wear particles commonly released from the articulating surfaces of joint prostheses, ultra-high-molecular-weight polyethylene particles were prepared in a joint simulator and injected into rat knees. The particles caused synovial proliferation and induced a macrophage and multinucleate giant-cell response in the subsynovium. Of particular interest was the macrophage response to particles ranging from 5 microns in maximum dimension to the limits of resolution of the light microscope; the multinucleate giant-cell response occurred in response to larger particles and aggregates of small particles. These findings emphasize the importance of wear particles in causing an adverse tissue response around joint replacements having a polyethylene component. The difference in cellular response to wear particles of different size suggests that not only the prosthesis material but also the pattern of wear and size of wear particles produced at the articulating surfaces of a prosthesis will determine the type of cellular response.

Serum ionised calcium and its relationship to parathyroid hormone after tibial fracture

The changes in serum adjusted ionised calcium and parathyroid hormone (PTH) were prospectively studied in 32 patients with isolated tibial fractures, treated conservatively. We measured serum albumin, adjusted total calcium, phosphate, pH, adjusted ionised calcium and PTH at intervals until the fractures had healed. The mean ionised calcium adjusted for pH fell within 24 hours of injury, and then rose to a peak at between four and six weeks. These changes cannot be explained by changes in serum pH or PTH. The restoration of normal ionised calcium levels after fracture coincided with the period when the callus was being calcified. Analysis of the changes in ionised calcium, phosphate and PTH suggests that PTH levels alter in response to changes in ionised calcium levels. PTH is highest immediately after fracture and lowest, often not recordable, at six weeks. The cause of the changes in the ionised calcium level has yet to be elucidated.

The differences in toxicity and release of bone-resorbing mediators induced by titanium and cobalt-chromium-alloy wear particles

We investigated the relationship between the toxic effects of metal wear particles and their ability to stimulate the release of inflammatory mediators implicated in bone resorption. In vitro studies were carried out with use of rat peritoneal macrophages, which were exposed to either cobalt-chromium-alloy or titanium-aluminum-vanadium particles, milled from the metal components of hip prostheses. The particles were in the size-range of, and at concentrations similar to, those found in the tissues surrounding failed prostheses in humans. The titanium-aluminum-vanadium particles showed little toxicity even at high concentrations, while the cobalt-chromium particles were very toxic. The titanium-aluminum-vanadium particles induced significantly more release of prostaglandin E2 than did the cobalt-chromium particles, and this was true for a wide range of concentrations. Exposure to titanium-aluminum-vanadium increased the release of prostaglandin E2, interleukin-1, tumor necrosis factor, and interleukin-6. In contrast, exposure to cobalt-chromium particles was associated with a decreased release of prostaglandin E2 and interleukin-6, and it had little effect on the release of interleukin-1 and tumor necrosis factor.

A study of protein turnover in preterm neonates using 15N enrichment of urinary ammonia

Hydrolysed yeast protein labelled with 15N was used to measure protein turnover, protein synthesis and protein breakdown in preterm infants. The yeast tracer was given as a bolus intragastric dose and protein turnover was determined from the 15N enrichment of urinary ammonia over known periods of about 12 h. Six boys (birthweight less than 1500 g) with gestation of 27-35 weeks were studied either two or three times at post-natal ages ranging from 13 to 54 d. There was no significant correlation between protein turnover with increasing post-conceptional or post-natal age. There was considerable interindividual variation and reproducibility varied between different infants. We suggest that this is a convenient non-invasive technique for monitoring serially nitrogen and protein metabolism in infants and that as such it merits further assessment.

Effect of different carbohydrates on growth, polysaccharidase and glycosidase production by Bacteroides ovatus, in batch and continuous culture

Bacteroides ovatus was grown in batch culture on 12 different carbon sources (five polysaccharides, seven monosaccharides and disaccharides). Specific growth rates were determined for each substrate together with polysaccharidase and glycosidase activities. Growth rates on polymerized carbohydrates were as fast or faster than on corresponding simple sugars, demonstrating that the rate of polysaccharide depolymerization was not a factor limiting growth. Bacteroides ovatus synthesized a large range of polymer-degrading enzymes. These polysaccharidases and glycosidases were generally repressed during growth on simple sugars, but arabinose was required for optimal production of alpha-arabinofuranosidase. Polysaccharidase and glycosidase activities were measured in continuous cultures grown with either xylan or guar gum under putative carbon limitation. With the exception of beta-xylosidase, activities of the polymer-degrading enzymes were inversely related to growth rate. This correlated with polysaccharide utilization which was greatest at low dilution rates. These results show that Bact. ovatus is highly adapted for growth on polymerized carbohydrate in the human colon and confirm that the utilization of polysaccharides is partly regulated at the level of enzyme synthesis.