Identification of Formaldehyde-Induced DNA-RNA Cross-Links in the A/J Mouse Lung Tumorigenesis Model.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent lung carcinogen present in tobacco products, and exposure to it is likely one of the factors contributing to the development of lung cancer in cigarette smokers. To exert its carcinogenic effects, NNK must be metabolically activated into highly reactive species generating a wide spectrum of DNA damage. We have identified a new class of DNA adducts, DNA-RNA cross-links found for the first time in NNK-treated mice lung DNA using our improved high-resolution accurate mass segmented full scan data-dependent neutral loss MS3 screening strategy. The levels of these DNA-RNA cross-links were found to be significantly higher in NNK-treated mice compared to the corresponding controls, which is consistent with higher levels of formaldehyde due to NNK metabolism as compared to endogenous levels. We hypothesize that this DNA-RNA cross-linking occurs through reaction with NNK-generated formaldehyde and speculate that this phenomenon has broad implications for NNK-induced carcinogenesis. The structures of these cross-links were characterized using high-resolution LC-MS2 and LC-MS3 accurate mass spectral analysis and comparison to a newly synthesized standard. Taken together, our data demonstrate a previously unknown link between DNA-RNA cross-link adducts and NNK and provide a unique opportunity to further investigate how these novel NNK-derived DNA-RNA cross-links contribute to carcinogenesis in the future.

Childhood Systemic Lupus Erythematosus: Presentation, management and long-term outcomes in an Australian cohort.

OBJECTIVES: Systemic Lupus Erythematosus (SLE) is a serious autoimmune disease often resulting in major end-organ damage and increased mortality. Currently, no data exists focussing on the presentation, long-term management and progression of SLE in the Australian paediatric population. We conducted the first Australian longitudinal review of childhood SLE, focussing on response to treatment and outcomes. METHODS: Detailed clinical and laboratory data of 42 children diagnosed with SLE before 16 years from 1998 to 2018 resident in Western Australia was collected. Data was collected at diagnosis and key clinical review time points and compared using the Systemic Lupus Collaborating Clinics (SLICC) and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) criteria. End organ damage was assessed against Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). Incidence rates of disease complications and end organ damage were determined. RESULTS: Of the 42 children, 88% were female with average age at diagnosis of 12.5 years. Indigenous Australians were over represented with an incidence rate 18-fold higher than non-Indigenous, although most children were Caucasian, reflecting the demographics of the Australian population. Median duration of follow-up was 4.25 years. On final review, 28.6% had developed cumulative organ damage as described by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (incidence rate: 0.08/PY (95% CI 0.04-0.14)), and one child died. Twenty-nine children had renal involvement (incidence rate: 0.38/PY (95% CI 0.26-0.56)). Of the 27 patients with biopsy proven lupus nephritis, 70% had Class III or IV disease. Average length of prednisolone use from diagnosis was 32.5 months. Hydroxychloroquine (n = 36) and mycophenolate mofetil (n =21) were the most widely used steroid sparing agents. 61.9% received rituximab and/or cyclophosphamide. CONCLUSION: This is the first longitudinal retrospective review of Australian children with SLE, with a markedly higher incidence in Indigenous children. Although improving, rates of end organ complications remain high, similar to international cohort outcomes. Longitudinal multi-centre research is crucial to elucidate risk factors for poor outcomes, and identifying those warranting early more aggressive therapy.

High-throughput Identification of FLT3 Wild-type and Mutant Kinase Substrate Preferences and Application to Design of Sensitive In Vitro Kinase Assay Substrates.

Acute myeloid leukemia (AML) is an aggressive disease that is characterized by abnormal increase of immature myeloblasts in blood and bone marrow. The FLT3 receptor tyrosine kinase plays an integral role in hematopoiesis, and one third of AML diagnoses exhibit gain-of-function mutations in FLT3, with the juxtamembrane domain internal tandem duplication (ITD) and the kinase domain D835Y variants observed most frequently. Few FLT3 substrates or phosphorylation sites are known, which limits insight into FLT3's substrate preferences and makes assay design particularly challenging. We applied in vitro phosphorylation of a cell lysate digest (adaptation of the Kinase Assay Linked with Phosphoproteomics (KALIP) technique and similar methods) for high-throughput identification of substrates for three FLT3 variants (wild-type, ITD mutant, and D835Y mutant). Incorporation of identified substrate sequences as input into the KINATEST-ID substrate preference analysis and assay development pipeline facilitated the design of several peptide substrates that are phosphorylated efficiently by all three FLT3 kinase variants. These substrates could be used in assays to identify new FLT3 inhibitors that overcome resistant mutations to improve FLT3-positive AML treatment.

Management of Children with Juvenile Idiopathic Arthritis.

Juvenile idiopathic arthritis (JIA) comprises a group of heterogeneous disorders of chronic arthritis in childhood and remains the commonest pediatric rheumatic disease associated with significant long-term morbidity. Advances in understanding of the pathogenesis, better definition of disease control/remission measures, and the arrival of biological agents have improved the outcomes remarkably. Methotrexate (Mtx) remains the first-line disease modifying (DMARD) therapy for most children with JIA due to its proven efficacy and safety. Sulphosalazine (SSz) (especially for enthesitis) and leflunomide may also have a secondary role. Tumor necrosis factor inhibitors (TNF-I), alone or in combination with Mtx have shown tremendous benefit in children with polyarticular JIA, enthesitis related arthritis (ERA) and psoriatic arthritis. Tocilizumab appears very efficacious in systemic arthritis and abatacept and tocilizumab also appear to benefit polyarticular JIA; the role of rituximab remains unclear, though clearly beneficial in adult RA. TNF-I with Mtx is also effective in uveitis associated with JIA. Biologicals have demonstrated an impressive safety record in children with JIA, although close monitoring for rare but potentially dangerous adverse events, such as tuberculosis and other infections; paradoxical development of additional autoimmune diseases; and possibly an increased risk of cancers is warranted.

Chronic recurrent multifocal osteomyelitis in children: nine years' experience at a statewide tertiary paediatric rheumatology referral centre.

OBJECTIVE: To describe the clinical features, management and outcome of 34 children with chronic recurrent multifocal osteomyelitis (CRMO) diagnosed at a single centre over 9 years. METHODS: All children identified with CRMO for the period 2005-13 were identified from a prospectively collected database, with additional data from hospital records. RESULTS: Thirty-four patients, 21 female and 13 male, were identified. The average age at symptom onset was 9.8 years (range 3.8-17.9) and at diagnosis was 10.9 years (range 5.2-18.2), with an average delay in diagnosis of 12 months. Follow-up was 0.3-7.9 years (average 2.1), with 104 individual bony lesions identified, with a median of 3 (range 1-9) per patient. Six patients had unifocal disease. The sites involved included the tibia (n = 19), femur (n = 14), clavicle (n = 12), vertebrae (n = 10) and fibula (n = 8). Approximately half of patients had an inflammatory arthritis at diagnosis, and two-thirds in total eventually developed an arthritis. Pustulosis occurred in eight patients (24%), severe acne in four (12%) and psoriasis in three (9%). NSAIDs were used in 91%, CSs in 82% and MTX in 38%. Two patients were treated with anti-TNF agents. Episodic disease was most common (79%), while 21% had a monophasic pattern. Clinical remission occurred in 94% of children, with prolonged remission in 17%. Seven patients did not require medications for >12 months. CONCLUSION: CRMO is more common than previously recognized, but diagnosis may be delayed. Episodic multifocal disease was most common, but some had unifocal and/or monophasic disease. Most patients responded to NSAIDs and/or intermittent CSs, but many required DMARDs.

Inherited multicentric osteolysis: case report of three siblings treated with bisphosphonate.

Inherited Multicentric Osteolysis (IMO) is an uncommon familial condition of idiopathic pathophysiology causing bone osteolysis and dysplasia. These patients present with common rheumatologic complaints of pain, dysfunction and disability, and are often initially misdiagnosed as a chronic rheumatic disease of childhood such as juvenile idiopathic arthritis. We report a case of three siblings diagnosed with IMO. Diagnosis was made during childhood, with each sibling having different manifestations and course of disease. One had a previous history of bilateral hip dysplasia. Two had osteolysis of the foot, distal tibia and femur (lower limb bones), whilst one had osteolysis of the rib and unusual clavicular fractures. Unusually, all siblings appear to experience decreased pain sensation compared to norms. All siblings were treated with bisphosphonates and experienced a rapid improvement in pain symptoms, decreased analgesic requirements. Two had bone mineral density testing performed and both had increases post-bisphosphonate. In all three, there was subjective evidence of stabilisation of bone disease. Testing for matrix metalloproteinase-2 (MMP2) gene was negative.

Use of bisphosphonates for the treatment of osteonecrosis as a complication of therapy for childhood acute lymphoblastic leukaemia (ALL).

BACKGROUND: Osteonecrosis is a well-recognised complication of current childhood acute lymphoblastic leukaemia (ALL) therapy. There are few studies on the medical management of osteonecrosis in this setting. We studied the therapeutic and radiological effects of oral and intravenous bisphosphonate use compared with standard care as treatment for osteonecrosis in this population. METHOD: Patients who developed osteonecrosis as a complication of ALL therapy between 1994 and 2007 were treated at a single paediatric institution. Of 17 patients, 9 were commenced on bisphosphonates and 8 treated conservatively. Both groups were observed with time. Pain, analgesic requirement and musculoskeletal function were assessed monthly. Affected joints were radiologically imaged at set intervals. Each scan was graded using an ellipsoid method to give the total volume of osteonecrosis, by blinded radiologic examination. RESULTS: Three of six patients treated with oral alendronate showed clinical improvement. The three patients that had no improvement were subsequently treated with intravenous pamidronate. All six patients treated with intravenous pamidronate showed clinical improvement. Seven of eight conservatively treated patients deteriorated clinically. All patients demonstrated reduction in the radiological burden of osteonecrosis with time. There was no difference in the rate of reduction between conservative and bisphosphonate arms. CONCLUSION: Bisphosphonate use, in particular pamidronate, improved pain scores, analgesic requirement and musculoskeletal function in patients with osteonecrosis occurring as a complication of childhood ALL therapy. Objective radiologic benefit of bisphosphonate treatment could not be demonstrated. Risks, benefits and long-term outcome of bisphosphonate use in this population should be addressed in a larger prospective, randomised trial.

Analysis of 1p, 19q, 9p, and 10q as prognostic markers for high-grade astrocytomas using fluorescence in situ hybridization on tissue microarrays from Radiation Therapy Oncology Group trials.

Survival periods vary considerably for patients with high-grade astrocytomas, and reliable prognostic markers are not currently available. We therefore investigated whether genetic losses from chromosomes 1p, 19q, 9p, or 10q were associated with survival in 89 high-grade astrocytomas using tissue microarrays (TMAs) derived from Radiation Therapy Oncology Group clinical trials. Cases included 15 anaplastic astrocytomas (AAs) and 74 glioblastomas (GBMs) selected on the basis of survival times significantly shorter or longer than the expected median. Genetic analysis was performed by TMA-fluorescence in situ hybridization (FISH) on array sections using 8 DNA probes, including those directed at 1p32, 19q13.4, 9p21 (p16/CDKN2A), and 10q (PTEN and DMBT1). Genetic status for each locus was correlated with patient survival group, and data were analyzed by using Fisher's exact test of association (adjusted P = 0.025). Losses of chromosome 1p, either alone or in combination with 19q, were encountered in only 2 cases, both AAs. This contrasts with oligodendrogliomas, in which combined 1p and 19q losses are frequent and predictive of prolonged survival. Solitary 19q loss was noted in 3/15 AAs and in 7/70 GBMs and was more frequent in the long-term survival group (P = 0.041, AA and GBM combined). Chromosome 9p loss was seen in 5/8 AAs and 39/57 GBMs, whereas chromosome 10q loss was detected in 4/15 AAs and 48/68 GBMs. The 9p and 10q deletions were slightly more frequent in short-term survivors, though none of the comparisons achieved statistical significance. Long-term and short-term survival groups of high-grade astrocytomas appear to have dissimilar frequencies of 19q, 9p, and 10q deletions. TMA-FISH is a rapid and efficient way of evaluating genetic alterations in such tumors.

Advanced therapy for juvenile arthritis.

The management of juvenile idiopathic arthritis (JIA) has undergone dramatic changes in the last decade with undoubtedly great benefit for many patients. In particular, more effective use of available drugs and the application of newly discovered drugs have been responsible for much of this improvement. Methotrexate is the gold standard for management of moderate to severe polyarthritis. Other disease-modifying antirheumatic drugs (DMARDs) such as sulphasalazine and cyclosporine are finding a specific role for resistant disease where they may be used in combination with methotrexate, for example. The introduction of anti-TNF agents, such as etanercept, is likely to herald a major shift to the use of biological agents in those intolerant to, or unresponsive to, standard DMARD therapy. DMARDs provide major steroid spring effect in many children with severe JIA with the hope that osteoporosis and growth failure will be reduced. More judicious use of corticosteroids and techniques such as intravenous 'pulse therapy' rather than long-term high-dose use of oral corticosteroids are also major changes. Intra-articular corticosteroids are commonly used in children with oligoarticular JIA and as a useful adjunct to DMARD therapy in children with other forms of JIA. Autologous stem cell transplantation is an exciting new development currently restricted to use in patients with very severe, resistant disease. Modifications of technique, experience and increased safety may make this a more widely applicable technique, in particular for patients with a poor prognosis, such as those with systemic JIA. Although the focus of this chapter is on drug therapy, multidisciplinary team management for children with chronic arthritis focusing on the physical, nutritional, intellectual and psychosocial wellbeing of the child will continue to be important.