Roger Olofsson Bagge

MicroRNA in exosomes isolated directly from the liver circulation in patients with metastatic uveal melanoma.

BackgroundUveal melanoma is a tumour arising from melanocytes of the eye, and 30 per cent of these patients develop liver metastases. Exosomes are small RNA containing nano-vesicles released by most cells, including malignant melanoma cells. This clinical translational study included patients undergoing isolated hepatic perfusion (IHP) for metastatic uveal melanoma, from whom exosomes were isolated directly from liver perfusates. The objective was to determine whether exosomes are present in the liver circulation, and to ascertain whether these may originate from melanoma cells.MethodsExosomes were isolated from the liver perfusate of twelve patients with liver metastases from uveal melanoma undergoing IHP. Exosomes were visualised by electron microscopy, and characterised by flow cytometry, Western blot and real-time PCR. Furthermore, the concentration of peripheral blood exosomes were measured and compared to healthy controls.ResultsThe liver perfusate contained Melan-A positive and RNA containing exosomes, with similar miRNA profiles among patients, but dissimilar miRNA compared to exosomes isolated from tumor cell cultures. Patients with metastatic uveal melanoma had a higher concentration of exosomes in their peripheral venous blood compared to healthy controls.ConclusionsMelanoma exosomes are released into the liver circulation in metastatic uveal melanoma, and is associated with higher concentrations of exosomes in the systemic circulation. The exosomes isolated directly from liver circulation contain miRNA clusters that are different from exosomes from other cellular sources.

BRAFV600 inhibition alters the microRNA cargo in the vesicular secretome of malignant melanoma cells

Significance The development of BRAF inhibitors is a notable clinical success, leading to rapid initial melanoma regression. However, response rates are tempered by a short duration of response in a majority of patients. This study has determined the effects of BRAF inhibition on mutant melanoma cells, as well as on the RNA contents in their vesicular secretome. Our data show the presence of miR-211–5p in all extracellular vesicular (EV) subsets upon treatment with BRAF inhibitors, which provides a fundamental starting point to understand the regulatory effects of molecules present in EVs, which may have implications for disease progression in patients receiving BRAF-targeted treatment. The BRAF inhibitors vemurafenib and dabrafenib can be used to treat patients with metastatic melanomas harboring BRAFV600 mutations. Initial antitumoral responses are often seen, but drug-resistant clones with reactivation of the MEK–ERK pathway soon appear. Recently, the secretome of tumor-derived extracellular vesicles (EVs) has been ascribed important functions in cancers. To elucidate the possible functions of EVs in BRAF-mutant melanoma, we determined the RNA content of the EVs, including apoptotic bodies, microvesicles, and exosomes, released from such cancer cells after vemurafenib treatment. We found that vemurafenib significantly increased the total RNA and protein content of the released EVs and caused significant changes in the RNA profiles. RNA sequencing and quantitative PCR show that cells and EVs from vemurafenib-treated cell cultures and tumor tissues harvested from cell-derived and patient-derived xenografts harbor unique miRNAs, especially increased expression of miR-211–5p. Mechanistically, the expression of miR-211–5p as a result of BRAF inhibition was induced by increased expression of MITF that regulates the TRPM1 gene resulting in activation of the survival pathway. In addition, transfection of miR-211 in melanoma cells reduced the sensitivity to vemurafenib treatment, whereas miR-211–5p inhibition in a vemurafenib resistant cell line affected the proliferation negatively. Taken together, our results show that vemurafenib treatment induces miR-211–5p up-regulation in melanoma cells both in vitro and in vivo, as well as in subsets of EVs, suggesting that EVs may provide a tool to understand malignant melanoma progression.

Regional hyperthermic perfusion with melphalan after surgery for recurrent malignant melanoma of the extremities – Long-term follow-up of a randomised trial

Abstract Introduction: Isolated limb perfusion (ILP) is a treatment option most commonly used in the treatment of melanoma in-transit metastases of the extremities. The principle idea is to surgically isolate a region of the body and then deliver a high concentration of a chemotherapeutic agent together with hyperthermia. There have been three randomised trials exploring whether adjuvant ILP to patients with recurrent or high-risk primary melanomas increases survival; one of these trials has now been updated with a 25-year follow-up. Methods: The original study randomised 69 patients (between 1981 and 1989) with their first satellite or in-transit recurrence to either wide excision (WE group, n = 36 patients) or to WE and adjuvant ILP (WE + ILP group, n = 33 patients). Follow-up data 25 years later concerning survival and cause of death was retrieved from the Swedish National Cause of Death Register. Results: In the WE + ILP group there were 20 deaths (61%) due to melanoma compared with 26 deaths (72%) in the WE group (p = 0.31). Median melanoma-specific survival was 95 months for WE + ILP compared to 38 months for the WE group, an almost 5 year benefit without statistical significance (p = 0.24). Discussion: There is no evidence that adjuvant ILP prolongs survival in patients with high-risk or recurrent melanoma; however, the existing randomised trials are largely underpowered to detect such a difference. New studies are exploring systemic immunological effects of ILP, and a combination of regional therapy and immunotherapy may serve as a rationale for new trials using ILP in the future.

Hypoxia-regulated gene expression explains differences between melanoma cell line-derived xenografts and patient-derived xenografts

Cell line-derived xenografts (CDXs) are an integral part of drug efficacy testing during development of new pharmaceuticals against cancer but their accuracy in predicting clinical responses in patients have been debated. Patient-derived xenografts (PDXs) are thought to be more useful for predictive biomarker identification for targeted therapies, including in metastatic melanoma, due to their similarities to human disease. Here, tumor biopsies from fifteen patients and ten widely-used melanoma cell lines were transplanted into immunocompromised mice to generate PDXs and CDXs, respectively. Gene expression profiles generated from the tumors of these PDXs and CDXs clustered into distinct groups, despite similar mutational signatures. Hypoxia-induced gene signatures and overexpression of the hypoxia-regulated miRNA hsa-miR-210 characterized CDXs. Inhibition of hsa-miR-210 with decoys had little phenotypic effect in vitro but reduced sensitivity to MEK1/2 inhibition in vivo, suggesting down-regulation of this miRNA could result in development of resistance to MEK inhibitors.

BET bromodomain inhibitors synergize with ATR inhibitors in melanoma

Metastatic malignant melanoma continues to be a challenging disease despite clinical translation of the comprehensive understanding of driver mutations and how melanoma cells evade immune attack. In Myc-driven lymphoma, efficacy of epigenetic inhibitors of the bromodomain and extra-terminal domain (BET) family of bromodomain proteins can be enhanced by combination therapy with inhibitors of the DNA damage response kinase ATR. Whether this combination is active in solid malignancies like melanoma, and how it relates to immune therapy, has not previously investigated. To test efficacy and molecular consequences of combination therapies cultured melanoma cells were used. To assess tumor responses to therapies in vivo we use patient-derived xenografts and B6 mice transplanted with B16F10 melanoma cells. Concomitant inhibition of BET proteins and ATR of cultured melanoma cells resulted in similar effects as recently shown in lymphoma, such as induction of apoptosis and p62, implicated in autophagy, senescence-associated secretory pathway and ER stress. In vivo, apoptosis and suppression of subcutaneous growth of patient-derived melanoma and B16F10 cells were observed. Our data suggest that ATRI/BETI combination therapies are effective in melanoma.

Isolated hepatic perfusion as a treatment for liver metastases of uveal melanoma.

Isolated hepatic perfusion (IHP) is a procedure where the liver is surgically isolated and perfused with a high concentration of the chemotherapeutic agent melphalan. Briefly, the procedure starts with the setup of a percutaneous veno-venous bypass from the femoral vein to the external jugular vein. Via a laparotomy, catheters are then inserted into the proper hepatic artery and the caval vein. The portal vein and the caval vein, both supra- and infrahepatically, are then clamped. The arterial and venous catheters are connected to a heart lung machine and the liver is perfused with melphalan (1 mg/kg body weight) for 60 min. This way it is possible to locally perfuse the liver with a high dose of a chemotherapeutic agent, without leakage to the systemic circulation. In previous studies including patients with isolated liver metastases of uveal melanoma, an overall response rate of 33-100% and a median survival between 9 and 13 months, have been reported. The aim of this protocol is to give a clear description of how to perform the procedure and to discuss IHP as a treatment option for liver metastases of uveal melanoma.

Melphalan, Antimelanoma Immunity, and Inflammation—Letter

The recent study by Dudek-Peric and colleagues aimed at delineating immunogenic properties of melphalan, with focus on its use in isolated limb perfusion (Mel-ILP) in metastatic melanoma ([1][1]). The authors demonstrated that mice vaccinated with melphalan-treated melanoma cells were protected

The Effect of Perfusate Buffering on Toxicity and Response in Isolated Hepatic Perfusion for Uveal Melanoma Liver Metastases

Abstract Background: Isolated hepatic perfusion (IHP) is a treatment option for patients with liver metastases. Previous studies have found that liver toxicity is one of the limiting factors, and in an attempt to reduce the toxicity a buffering agent was added to the perfusate. The aim was to retrospectively analyse if this buffering reduced toxicity and complication rates. Methods: A retrospective review of 52 consecutive patients with uveal melanoma liver metastases treated with IHP between 2005 and 2013. Patients were followed by daily liver function tests (LFT). Toxicity was graded according to Common Terminology Criteria for Adverse Events version 4.0 (CTCAE; United States Department of Health & Human Services, Washington, D.C), complications according to Clavien-Dindo and response according to RECIST-criteria. Results: Thirty-six patients were treated with a buffered perfusate and 16 patients without buffer. There was no difference in age, gender, largest tumour size or number of tumours between the groups. There was a significantly lower mean in peak ALT, AST, PK (INR) and bilirubin when comparing buffer with no-buffer. There were five major complications without a significant difference between the groups (8.3 vs. 12.5%, p = 0.33). There was a lower complete response (CR) rate (11 vs. 44%, p = 0.023) and a trend for shorter time to local progression (9.2 vs. 17.6 months, p = 0.096); however, not significant in multivariate analysis. There was no difference in survival (24.2 vs. 26.0 months, p = 0.43) between the two groups. Conclusions: Adding buffer to the perfusate during IHP significantly reduces postoperative LFTs; however, without a reduced complication rate. Interestingly, buffering also seems to reduce the response rate; however, this did not translate into a survival difference. To address if buffering adds any clinical benefit to the patients concerning toxicity, a larger prospective trial is necessary.

Evaluation of intraoperative touch imprint cytology on axillary sentinel lymph nodes in invasive breast carcinomas, a retrospective study of 1227 patients comparing sensitivity in the different tumor subtypes

Background Intraoperative evaluation of the axillary sentinel lymph node (SLN) in patients with breast carcinoma reduces the need of re-operations in cases where an axillary completion lymph node dissection (CLND) is indicated. Different methods have been used to determine the SLN status intraoperatively, e.g. frozen section histology (FS) and touch imprint cytology (TIC). The sensitivity of intraoperative TIC examination on SLN is not consistent between different studies and varies according to different tumor histologic subtypes, tumor size and the age of the patient. The aim of this study was to describe the specificity and sensitivity of TIC and to compare TIC sensitivity in the different histological subtypes of breast carcinoma. Methods A retrospective review was performed of 1227 consecutive clinically node negative breast cancer patients treated with sentinel lymph node biopsy (SLNB) with intraoperative TIC between the years 2003 and 2008. The SLN was bisected and stained using the May-Grünwald-Giemsa method and immunocytochemically with the antibody MNF-116. Results The overall sensitivity of the TIC test was 68.6% and the specificity was 99.8%. There was no statistically significant difference between the detection of SLN metastases from ductal carcinoma versus lobular carcinoma. The sensitivity improved over the period of the study. Conclusion TIC is highly specific with an acceptable overall sensitivity. The sensitivity increased under the period of the study and it was higher in cases with larger size of the primary tumor. There was no difference in TIC sensitivity between the different histological subtypes.

Sentinel node for malignant melanoma: an observational study of a consecutive single center experience

INTRODUCTION Sentinel node biopsy (SNB) for melanoma gives prognostic information, however the success is dependent on several factors. The aim of this study was to describe outcome data after the introduction of the technique at our centre, including analysis of false negative rate (FNR), predictive factors for positive sentinel node (SN) and non-sentinel node (NSN), as well as prognostic factors for melanoma-specific survival (MSS). MATERIALS AND METHODS This is a retrospective observational study of a prospectively kept database at Sahlgrenska University Hospital. Between March 2000 and December 2013, 769 consecutive patients with cutaneous malignant melanoma undergoing SNB were included. The median follow-up time was 55 months (2-179 months). Tumour load in the SN was categorized according to the largest tumour deposit, low when ≤1 mm and high when >1 mm. RESULTS The FNR was 20% and the SN positivity rate was 14% with a decrease in both FNR and SN positivity rate during the study period. In multivariate analysis the only predictive factor for a positive SN was Breslow thickness. The 5-year melanoma specific survival (MSS) was 81% and in multivariate analysis the prognostic factors were SN-status (low metastatic load HR = 2.6, p = 0.001; high metastatic load HR = 2.7, p = 0.004) followed by Breslow thickness and ulceration. CONCLUSIONS In this study Breslow thickness was the only independent predictive factor for a positive SN, no predictive factors were identified for NSN. Independent prognostic factors for MSS were SN status, Breslow thickness and ulceration. Interestingly, there was no survival difference depending on SN tumour burden when using 1 mm as cut-off.