Merkel cell polyomavirus oncoproteins induce microRNAs that suppress multiple autophagy genes.

Viruses can inhibit host autophagy through multiple mechanisms, and evasion of autophagy plays an important role in immune suppression and viral oncogenesis. Merkel cell polyomavirus (MCPyV) T-antigens are expressed and involved in the pathogenesis of a large proportion of Merkel cell carcinoma (MCC). Yet, how MCPyV induces tumorigenesis is not fully understood. Herein, we show that MCPyV T-antigens induce miR-375, miR-30a-3p and miR-30a-5p expressions, which target multiple key genes involved in autophagy, including ATG7, SQSTM1 (p62) and BECN1. In MCC tumors, low expression of ATG7 and p62 are associated with MCPyV-positive tumors. Ectopic expression of MCPyV small T-antigen and truncated large T-antigen (LT), but not the wild-type LT, resulted in autophagy suppression, suggesting the importance of autophagy evasion in MCPyV-mediated tumorigenesis. Torin-1 treatment induced cell death, which was attenuated by autophagy inhibitor, but not pan-caspase inhibitor, suggesting a potential role of autophagy in promoting cell death in MCC. Conceptually, our study shows that MCPyV oncoproteins suppress autophagy to protect cancer cells from cell death, which contribute to a better understanding of MCPyV-mediated tumorigenesis and potential MCC treatment.

MiR-375 Regulation of LDHB Plays Distinct Roles in Polyomavirus-Positive and -Negative Merkel Cell Carcinoma.

MicroRNA-375 (miR-375) is deregulated in multiple tumor types and regulates important targets involved in tumorigenesis and metastasis. This miRNA is highly expressed in Merkel cell carcinoma (MCC) compared to normal skin and other non-MCC skin cancers, and its expression is high in Merkel cell polyomavirus (MCPyV)-positive (MCPyV+) and low in MCPyV-negative (MCPyV-) MCC tumors. In this study, we characterized the function and target of miR-375 in MCPyV+ and MCPyV- MCC cell lines. Ectopic expression of miR-375 in MCPyV- MCC cells resulted in decreased cell proliferation and migration, as well as increased cell apoptosis and cell cycle arrest. However, in MCPyV+ MCC cells, inhibition of miR-375 expression reduced cell growth and induced apoptosis. Additionally, the expression of lactate dehydrogenase B (LDHB), a known target of miR-375, was inversely correlated with miR-375. Silencing of LDHB reduced cell growth in MCPyV- cell lines, while its silencing in MCPyV+ cell lines rescued the cell growth effect mediated by miR-375 inhibition. Together, our results suggest dual roles of miR-375 and LDHB in MCPyV and non-MCPyV-associated MCCs. We propose that LDHB could be a therapeutic target in MCC and different strategies should be applied in virus- and non-virus-associated MCCs.

Burn survivors' pulmonary and muscular impairment, exercise tolerance and return-to-work following medical-vocational rehabilitation: A long-term follow-up.

OBJECTIVE: To follow up the long-term outcome in return-to-work (RTW) rate in burn-injury patients, and to determine the degree of impairment in pulmonary and muscular function and exercise tolerance. DESIGN: A prospective, longitudinal follow-up study without a control group. PATIENTS: Twenty-five burn-injury patients referred for medical-vocational rehabilitation. METHODS: Return-to-work rate was followed after completed medical-vocational rehabilitation. Pulmonary function was evaluated with spirometry, diffusing capacity and radio spirometry. Exercise capacity was determined using a bicycle ergometer. Muscle functions evaluated in the arms and legs were: isokinetic torque, isometric strength, endurance and muscular strength utilization. RESULTS: Return-to-work rate was 87%. During bicycle exercise tests the patients, on average, reached their expected workloads. The dominating lung func-tion abnormality observed on lung scintigraphy was delayed wash-out time of inhaled radioactive xenon gas, suggesting airway obstruction. All tests of shoulder-flexor and knee-extensor muscle function showed large minimum-maximum differences. Mean isometric endurance of shoulder flexors was lower than mean of references, and isokinetic knee extensor torques were slightly lower. CONCLUSION: High return-to-work rates can be achieved after burn injury requiring hospital-ward care. Despite measurable impairments in muscle strength/endurance and pulmonary function in a substantial proportion of these patients, overall normal bicycle exercise capacity was observed except for a few cases.

Early assessment and identification of posttraumatic stress disorder, satisfaction with appearance and coping in patients with burns.

BACKGROUND: The first year after severe burn is a psychologically challenging period for the patient. Patients may still struggle with burn-related physical and psychological problems such as posttraumatic stress disorder (PTSD) and body image dissatisfaction (BID). AIM: This study investigates the presence of PTSD, BID and coping, at three, six and twelve months after discharge for early identification of patients in need of focused support during rehabilitation. METHODS: Fifty-two adult patients with different degrees of burns were followed at three, six and twelve months after discharge and 36 patients completed all assessment points. A standardized clinical protocol was used for systematic assessment of PTSD (IES-R), BID (SWAP-Swe) and Coping (CBQ). The follow-up included an intervention with a burn nurse as a complement to the existing program. RESULTS: Approximately half of the patients had a risk of developing PTSD three months after discharge from hospital, and body image dissatisfaction was found to potentially predict risk of PTSD during follow-up. CONCLUSIONS: The findings suggest that it is important to include patients with less extensive burns in follow-up as this group is at risk of development of PTSD. Using standardized questionnaires in early follow-up along with assessment of body image dissatisfaction may facilitate detection of psychological problems.

TERT promoter mutations and gene amplification: promoting TERT expression in Merkel cell carcinoma.

Telomerase activation through the induction of its catalytic component TERT is essential in carcinogenesis. The regulatory mechanism and clinical significance underlying cancer-specific TERT expression have been extensively investigated in various human malignancies, but little is known about these in Merkel cell carcinoma (MCC), an aggressive neuroendocrine skin tumor. Here we addressed these issues by determining TERT promoter mutations, gene amplification, mRNA expression and association with clinical variables in MCC. TERT mRNA was expressed in 6/6 MCC cell lines and 41 of 43 tumors derived from 35 MCC patients. Telomerase activity was detectable in all 6 cell lines and 11 tumors analyzed. TERT promoter mutations were identified in 1/6 cell lines and 4/35 (11.4%) MCC cases. The mutation exhibited UV signature and occurred in sun-exposed areas. Increased TERT gene copy numbers were observed in 1/6 cell lines and 11/14 (79%) tumors, and highly correlated with its mRNA expression (r = 0.7419, P = 0.0024). Shorter overall survival was significantly associated with higher TERT mRNA levels in MCC patients (P = 0.032). Collectively, TERT expression and telomerase activity is widespread in MCC, and may be attributable to TERT promoter mutations and gene amplification. Higher TERT expression predicts poor patient outcomes.

MicroRNA expression patterns related to merkel cell polyomavirus infection in human merkel cell carcinoma.

Merkel cell carcinoma (MCC) is an aggressive and lethal type of neuroendocrine skin cancer. Mutated Merkel cell polyomavirus (MCV) is commonly found in MCC, and leads to upregulation of the survivin oncogene. However, ∼20% of MCC tumors do not have detectable MCV, suggesting alternative etiologies for this tumor type. In this study, our aim was to evaluate microRNA (miRNA) expression profiles and their associations with MCV status and clinical outcomes in MCC. We showed that miRNA expression profiles were distinct between MCV-positive (MCV+) and MCV-negative (MCV-) MCCs and further validated that miR-203, miR-30a-3p, miR-769-5p, miR-34a, miR-30a-5p, and miR-375 were significantly different. We also identified a subset of miRNAs associated with tumor metastasis and MCC-specific survival. Functionally, overexpression of miR-203 was found to inhibit cell growth, induce cell cycle arrest, and regulate survivin expression in MCV- MCC cells, but not in MCV+ MCC cells. Our findings reveal a mechanism of survivin expression regulation in MCC cells, and provide insights into the role of miRNAs in MCC tumorigenesis.

Differences in pain patterns for infected and noninfected patients with burn injuries.

The management of pain is a primary issue in burn care. Patients hospitalized for burn injuries experience severe pain on a daily basis, immediately after the injury and during the healing of the burn wound. Our clinical experience is that the intensity of pain is increased by wound infection. The purpose of this study was to investigate retrospectively whether patients experience increased pain intensity in conjunction with wound infection. A total of 165 patients with burn injuries were included, 60 of whom were diagnosed with infection. The results of this study showed a significant increase in pain intensity in association with infection. An increase in pain is one of the factors to be considered among the many assessments, tests, and treatments for patients with burn injuries.

A prospective study of infections in burn patients.

In a 3-year prospective study, all infections presenting in the burns unit of a university hospital were registered in a specially designed database. Two-hundred and thirty adult patients were included. Eighty-three patients had in all 176 infections, giving an infection rate of 48 per 1000 patient days including both nosocomial and community-acquired infections. Thirty-five blood-stream infections (BSI) occurred in 22 patients; most common micro-organisms were coagulase-negative staphylococci and methicillin-sensitive Staphylococcus aureus. The device-specific BSI rate was 6 per 1000 central venous catheter days, which is low compared to other burn units. The pneumonia rate was 41 per 1000 ventilator days. Seventy-two patients had 107 burn wound infections. Antibiotics were given to only 50% of the burn patients, including 96% of the patients with infection and 26% of those without infection. Most frequently used antimicrobials were cloxacillin, penicillin and gentamicin. The antibiotic resistance rates were low, and multi-resistant bacteria or fungi were rare. The database can be used to evaluate the effects of changes in burn treatment, staffing and design of burn units, and antimicrobial resistance development in relation to antibiotic usage.