93 research outputs found

    Clusterin Regulates Drug-Resistance in Melanoma Cells

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    Clusterin has recently been shown to act as an antiapoptotic protein that confers drug-resistance in models of epithelial tumors. The aim of our work was to provide an insight into a possible role of clusterin in the regulation of drug-resistance in melanoma. In tissue samples, clusterin expression was low in nevi, but high in primary melanoma and melanoma metastases. Clusterin was also strongly expressed in melanoma cell lines, but was barely detectable in cultured melanocytes. To elucidate a possible role of clusterin in drug-resistance of melanoma, clusterin expression was regulated by either plasmid-driven overexpression or by antisense-mediated downregulation. Clusterin overexpression was associated with an increase in drug-resistance, i.e., with an increased survival of melanoma cells in the presence of cytotoxic drugs. In contrast, downregulation of clusterin by 2′-O-(2-methoxy)ethyl (2′MOE)-modified antisense oligonucleotides (AS-ODN) directed against clusterin mRNA significantly reduced drug-resistance, i.e., decreased survival of melanoma cells in the presence of cytotoxic drugs. To evaluate the effects of clusterin-antisense treatment in vivo, we applied an SCID-mouse/human-melanoma xenotransplantation model. Pre-treatment of mice with the 2′MOE-modified clusterin AS-ODN was associated with a significantly improved tumor response to dacarbazine as compared with animals pretreated with a scrambled control oligonucleotide. Taken together, we show that clusterin is strongly expressed in melanoma. Downregulation of clusterin reduces drug-resistance, i.e., reduces melanoma cell survival in response to cytotoxic drugs in vitro and in vivo. Thus, reducing clusterin expression may provide a novel tool to overcome drug-resistance in melanoma

    Proton Pump Inhibitor Use and Efficacy of Nivolumab and Ipilimumab in Advanced Melanoma

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    The impact of proton pump inhibitors (PPIs) on clinical outcomes with first-line immune checkpoint inhibitors (ICIs) in patients with metastatic melanoma was previously analyzed in the phase II study, CheckMate 069. This retrospective analysis utilized data from three phase II/III studies of first-line ICI therapy in untreated advanced melanoma: CheckMate 066, 067, and 069. All randomized patients with PPI use ≤ 30 days before initiating study treatment were included in the PPI-use subgroup. Possible associations between baseline PPI use and efficacy were evaluated within each treatment arm of each study using multivariable modeling. Approximately 20% of 1505 randomized patients across the studies reported baseline PPI use. The median follow-up was 52.6–58.5 months. Objective response rate (ORR), progression-free survival (PFS), and overall survival analyses provided insufficient evidence of a meaningful association between PPI use and efficacy outcomes with nivolumab-plus-ipilimumab, nivolumab, or ipilimumab therapy. In five of the six ICI treatment arms, 95% confidence intervals for odds ratios or hazard ratios traversed 1. Significant associations were observed in the CheckMate 069 combination arm between PPI use and poorer ORR and PFS. This multivariable analysis found insufficient evidence to support meaningful associations between PPI use and ICI efficacy in patients with advanced melanoma

    IMRT in oral cavity cancer

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    BACKGROUND: Except for early T1,2 N0 stages, the prognosis for patients with oral cavity cancer (OCC) is reported to be worse than for carcinoma in other sites of the head and neck (HNC). The aim of this work was to assess disease outcome in OCC following IMRT. Between January 2002 and January 2007, 346 HNC patients have been treated with curative intensity modulated radiation therapy (IMRT) at the Department of Radiation Oncology, University Hospital Zurich. Fifty eight of these (16%) were referred for postoperative (28) or definitive (30) radiation therapy of OCC. 40 of the 58 OCC patients (69%) presented with locally advanced T3/4 or recurred lesions. Doses between 60 and 70 Gy were applied, combined with simultaneous cisplatin based chemotherapy in 78%. Outcome analyses were performed using Kaplan Meier curves. In addition, comparisons were performed between this IMRT OCC cohort and historic in-house cohorts of 33 conventionally irradiated (3DCRT) and 30 surgery only patients treated over the last 10 years. RESULTS: OCC patients treated with postoperative IMRT showed the highest local control (LC) rate of all assessed treatment sequence subgroups (92% LC at 2 years). Historic postoperative 3DCRT patients and patients treated with surgery alone reached LC rates of ~70–80%. Definitively irradiated patients revealed poorest LC rates with ~30 and 40% following 3DCRT and IMRT, respectively. T1 stage resulted in an expectedly significantly higher LC rate (95%, n = 19, p < 0.05) than T2-4 and recurred stages (LC ~50–60%, n = 102). Analyses according to the diagnosis revealed significantly lower LC in OCC following definitive IMRT than that in pharyngeal tumors treated with definitive IMRT in the same time period (43% vs 82% at 2 years, p < 0.0001), while the LC rate of OCC following postoperative IMRT was as high as in pharyngeal tumors treated with postoperative IMRT (>90% at 2 years). CONCLUSION: Postoperative IMRT of OCC resulted in the highest local control rate of the assessed treatment subgroups. In conclusion, generous indication for IMRT following surgical treatment is recommended in OCC cases with unfavourable features like tight surgical margin, nodal involvement, primary tumor stage >T1N0, or already recurred disease, respectively. Loco-regional outcome of OCC following definitive IMRT remained unsatisfactory, comparable to that following definitive 3DCRT

    Migratory Dermal Dendritic Cells Act as Rapid Sensors of Protozoan Parasites

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    Dendritic cells (DC), including those of the skin, act as sentinels for intruding microorganisms. In the epidermis, DC (termed Langerhans cells, LC) are sessile and screen their microenvironment through occasional movements of their dendrites. The spatio-temporal orchestration of antigen encounter by dermal DC (DDC) is not known. Since these cells are thought to be instrumental in the initiation of immune responses during infection, we investigated their behavior directly within their natural microenvironment using intravital two-photon microscopy. Surprisingly, we found that, under homeostatic conditions, DDC were highly motile, continuously crawling through the interstitial space in a Gαi protein-coupled receptor–dependent manner. However, within minutes after intradermal delivery of the protozoan parasite Leishmania major, DDC became immobile and incorporated multiple parasites into cytosolic vacuoles. Parasite uptake occurred through the extension of long, highly dynamic pseudopods capable of tracking and engulfing parasites. This was then followed by rapid dendrite retraction towards the cell body. DDC were proficient at discriminating between parasites and inert particles, and parasite uptake was independent of the presence of neutrophils. Together, our study has visualized the dynamics and microenvironmental context of parasite encounter by an innate immune cell subset during the initiation of the immune response. Our results uncover a unique migratory tissue surveillance program of DDC that ensures the rapid detection of pathogens

    Measurement of the airborne and resonant radiation efficiencies

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    The determination of the total and the resonant components of the radiation efficiency have been shown to be necessary for the accurate prediction of the resonant sound reduction index for the calculation of the flanking sound reduction according to a proposed revision of the ISO 15712 series. However, the total and the resonant radiation efficiency of lightweight building elements can be difficult to determine experimentally and there is often confusion about what has actually been measured. In this paper, measurements in the laboratory of the components of the radiation efficiency are presented for different lightweight walls. The measurements were made using both sound intensity and sound pressure to determine the sound power radiated from the walls. Different methods of excitation are compared. A standard for the measurement of the components of the radiation efficiency of lightweight walls is necessary.Peer reviewed: YesNRC publication: Ye
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