Polyamine and EIF5A hypusination downstream of c-Myc confers targeted therapy resistance in BRAF mutant melanoma.

BACKGROUND: BRAF inhibitors are widely employed in the treatment of melanoma with the BRAF V600E mutation. However, the development of resistance compromises their therapeutic efficacy. Diverse genomic and transcriptomic alterations are found in BRAF inhibitor resistant melanoma, posing a pressing need for convergent, druggable target that reverse therapy resistant tumor with different resistance mechanisms. METHODS: CRISPR-Cas9 screens were performed to identify novel target gene whose inhibition selectively targets A375VR, a BRAF V600E mutant cell line with acquired resistance to vemurafenib. Various in vitro and in vivo assays, including cell competition assay, water soluble tetrazolium (WST) assay, live-dead assay and xenograft assay were performed to confirm synergistic cell death. Liquid Chromatography-Mass Spectrometry analyses quantified polyamine biosynthesis and changes in proteome in vemurafenib resistant melanoma. EIF5A hypusination dependent protein translation and subsequent changes in mitochondrial biogenesis and activity were assayed by O-propargyl-puromycin labeling assay, mitotracker, mitoSOX labeling and seahorse assay. Bioinformatics analyses were used to identify the association of polyamine biosynthesis with BRAF inhibitor resistance and poor prognosis in melanoma patient cohorts. RESULTS: We elucidate the role of polyamine biosynthesis and its regulatory mechanisms in promoting BRAF inhibitor resistance. Leveraging CRISPR-Cas9 screens, we identify AMD1 (S-adenosylmethionine decarboxylase 1), a critical enzyme for polyamine biosynthesis, as a druggable target whose inhibition reduces vemurafenib resistance. Metabolomic and proteomic analyses reveal that polyamine biosynthesis is upregulated in vemurafenib-resistant cancer, resulting in enhanced EIF5A hypusination, translation of mitochondrial proteins and oxidative phosphorylation. We also identify that sustained c-Myc levels in vemurafenib-resistant cancer are responsible for elevated polyamine biosynthesis. Inhibition of polyamine biosynthesis or c-Myc reversed vemurafenib resistance both in vitro cell line models and in vivo in a xenograft model. Polyamine biosynthesis signature is associated with poor prognosis and shorter progression free survival after BRAF/MAPK inhibitor treatment in melanoma cohorts, highlighting the clinical relevance of our findings. CONCLUSIONS: Our findings delineate the molecular mechanisms involving polyamine-EIF5A hypusination-mitochondrial respiration pathway conferring BRAF inhibitor resistance in melanoma. These targets will serve as effective therapeutic targets that can maximize the therapeutic efficacy of existing BRAF inhibitors.

Overcoming Vemurafenib Resistance in Metastatic Melanoma: Targeting Integrins to Improve Treatment Efficacy.

Metastatic melanoma, a deadly form of skin cancer, often develops resistance to the BRAF inhibitor drug vemurafenib, highlighting the need for understanding the underlying mechanisms of resistance and exploring potential therapeutic strategies targeting integrins and TGF-ß signalling. In this study, the role of integrins and TGF-ß signalling in vemurafenib resistance in melanoma was investigated, and the potential of combining vemurafenib with cilengitide as a therapeutic strategy was investigated. In this study, it was found that the transcription of PAI1 and p21 was induced by acquired vemurafenib resistance, and ITGA5 levels were increased as a result of this resistance. The transcription of ITGA5 was mediated by the TGF-ß pathway in the development of vemurafenib resistance. A synergistic effect on the proliferation of vemurafenib-resistant melanoma cells was observed with the combination therapy of vemurafenib and cilengitide. Additionally, this combination therapy significantly decreased invasion and colony formation in these resistant cells. In conclusion, it is suggested that targeting integrins and TGF-ß signalling, specifically ITGA5, ITGB3, PAI1, and p21, may offer promising approaches to overcoming vemurafenib resistance, thereby improving outcomes for metastatic melanoma patients.

Off-targets of BRAF inhibitors disrupt endothelial signaling and vascular barrier function.

Targeted therapies against mutant BRAF are effectively used in combination with MEK inhibitors (MEKi) to treat advanced melanoma. However, treatment success is affected by resistance and adverse events (AEs). Approved BRAF inhibitors (BRAFi) show high levels of target promiscuity, which can contribute to these effects. The blood vessel lining is in direct contact with high plasma concentrations of BRAFi, but effects of the inhibitors in this cell type are unknown. Hence, we aimed to characterize responses to approved BRAFi for melanoma in the vascular endothelium. We showed that clinically approved BRAFi induced a paradoxical activation of endothelial MAPK signaling. Moreover, phosphoproteomics revealed distinct sets of off-targets per inhibitor. Endothelial barrier function and junction integrity were impaired upon treatment with vemurafenib and the next-generation dimerization inhibitor PLX8394, but not with dabrafenib or encorafenib. Together, these findings provide insights into the surprisingly distinct side effects of BRAFi on endothelial signaling and functionality. Better understanding of off-target effects could help to identify molecular mechanisms behind AEs and guide the continued development of therapies for BRAF-mutant melanoma.

High levels of soluble CD73 unveil resistance to BRAF inhibitors in melanoma cells.

Melanoma cells express high levels of CD73 that produce extracellular immunosuppressive adenosine. Changes in the CD73 expression occur in response to tumor environmental factors, contributing to tumor phenotype plasticity and therapeutic resistance. Previously, we have observed that CD73 expression can be up-regulated on the surface of melanoma cells in response to nutritional stress. Here, we explore the mechanism by which melanoma cells release soluble CD73 under low nutrient availability and whether this might be affected by agents targeting the proto-oncogene B-Raf (BRAF). We found that starved melanoma cells can release high levels of CD73, able to convert AMP into adenosine, and this activity is abrogated by selective CD73 inhibitors, APCP or PSB-12489. The release of CD73 from melanoma cells is mediated by the matrix metalloproteinase MMP-9. Indeed, MMP-9 inhibitors significantly reduce the levels of CD73 released from the cells, while its surface levels increase. Of relevance, melanoma cells, harboring an activating BRAF mutation, upon treatment with dabrafenib or vemurafenib, show a strong reduction of CD73 cell expression and reduced levels of CD73 released into the extracellular space. Conversely, melanoma cells resistant to dabrafenib show high expression of membrane-bound CD73 and soluble CD73 released into the culture medium. In summary, our data indicate that CD73 is released from melanoma cells. The expression of CD73 is associated with response to BRAF inhibitors. Melanoma cells developing resistance to dabrafenib show increased expression of CD73, including soluble CD73 released from cells, suggesting that CD73 is involved in acquiring resistance to treatment.

ALDH1A1 confers resistance to RAF/MEK inhibitors in melanoma cells by maintaining stemness phenotype and activating PI3K/AKT signaling.

The mitogen-activated protein kinase (MAPK/ERK) pathway is pivotal in controlling the proliferation and survival of melanoma cells. Several mutations, including those in BRAF, exhibit an oncogenic effect leading to increased cellular proliferation. As a result, the combination therapy of a MEK inhibitor with a BRAF inhibitor demonstrated higher efficacy and lower toxicity than BRAF inhibitor alone. This combination has become the preferred standard of care for tumors driven by BRAF mutations. Aldehyde dehydrogenase 1A1 (ALDH1A1) is a known marker of stemness involved in drug resistance in several type of tumors, including melanoma. This study demonstrates that melanoma cells overexpressing ALDH1A1 displayed resistance to vemurafenib and trametinib through the activation of PI3K/AKT signaling instead of MAPK axis. Inhibition of PI3K/AKT signaling partially rescued sensitivity to the drugs. Consistently, pharmacological inhibition of ALDH1A1 activity downregulated the activation of AKT and partially recovered responsiveness to vemurafenib and trametinib. We propose ALDH1A1 as a new potential target for treating melanoma resistant to MAPK/ERK inhibitors.

COLUMBUS 7-year update: A randomized, open-label, phase III trial of encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF V600E/K-mutant melanoma.

BACKGROUND: Treatment with encorafenib plus binimetinib and encorafenib monotherapy is associated with improved progression-free survival (PFS) and overall survival (OS) compared with vemurafenib in patients with BRAF V600E/K-mutant metastatic melanoma. We report results from the 7-year analysis of COLUMBUS part 1 (NCT01909453) at 99.7 months (median duration between randomization and data cutoff). METHODS: 577 patients with locally advanced unresectable or metastatic BRAF V600E/K-mutant melanoma who were treatment-naive or progressed after first-line immunotherapy were randomized 1:1:1 to encorafenib 450 mg once daily (QD) plus binimetinib 45 mg twice daily (BID) (n = 192), vemurafenib 960 mg BID (n = 191), or encorafenib monotherapy 300 mg QD (n = 194). No prior BRAF/MEK inhibitor was allowed. RESULTS: Seven-year PFS and OS rates (95 % CI) were 21.2 % (14.7-28.4 %) and 27.4 % (21.2-33.9%) in the encorafenib plus binimetinib arm and 6.4 % (2.1-14.0 %) and 18.2 % (12.8-24.3 %) in the vemurafenib arm, respectively. Median melanoma-specific survival (95 % CI) was 36.8 months (27.7-51.5 months) in the encorafenib plus binimetinib arm and 19.3 months (14.8-25.9 months) in the vemurafenib arm. Thirty-four long-term responders (complete/partial response ongoing at 7 years) were identified across arms. CONCLUSIONS: This is the longest follow-up from a phase III trial of BRAF/MEK inhibitor combination in BRAF V600E/K-mutant metastatic melanoma. Safety results were consistent with the known tolerability profile of encorafenib plus binimetinib. Results support the long-term efficacy and known safety of encorafenib plus binimetinib in this population and provide new insights on long-term responders. Interactive data visualization is available at the COLUMBUS dashboard (https://clinical-trials.dimensions.ai/columbus7/).

Cholesterol neutralized vemurafenib treatment by promoting melanoma stem-like cells via its metabolite 27-hydroxycholesterol.

Vemurafenib has been used as first-line therapy for unresectable or metastatic melanoma with BRAFV600E mutation. However, overall survival is still limited due to treatment resistance after about one year. Therefore, identifying new therapeutic targets for melanoma is crucial for improving clinical outcomes. In the present study, we found that lowering intracellular cholesterol by knocking down DHCR24, the limiting synthetase, impaired tumor cell proliferation and migration and abrogated the ability to xenotransplant tumors. More importantly, administration of DHCR24 or cholesterol mediated resistance to vemurafenib and promoted the growth of melanoma spheroids. Mechanistically, we identified that 27-hydroxycholesterol (27HC), a primary metabolite of cholesterol synthesized by the enzyme cytochrome P450 27A1 (CYP27A1), reproduces the phenotypes induced by DHCR24 or cholesterol administration and activates Rap1-PI3K/AKT signaling. Accordingly, CYP27A1 is highly expressed in melanoma patients and upregulated by DHCR24 induction. Dafadine-A, a CYP27A1 inhibitor, attenuates cholesterol-induced growth of melanoma spheroids and abrogates the resistance property of vemurafenib-resistant melanoma cells. Finally, we confirmed that the effects of cholesterol on melanoma resistance require its metabolite 27HC through CYP27A1 catalysis, and that 27HC further upregulates Rap1A/Rap1B expression and increases AKT phosphorylation. Thus, our results suggest that targeting 27HC may be a useful strategy to overcome treatment resistance in metastatic melanoma.

Extracellular vesicles promote migration despite BRAF inhibitor treatment in malignant melanoma cells.

Extracellular vesicles (EVs) constitute a vital component of intercellular communication, exerting significant influence on metastasis formation and drug resistance mechanisms. Malignant melanoma (MM) is one of the deadliest forms of skin cancers, because of its high metastatic potential and often acquired resistance to oncotherapies. The prevalence of BRAF mutations in MM underscores the importance of BRAF-targeted therapies, such as vemurafenib and dabrafenib, alone or in combination with the MEK inhibitor, trametinib. This study aimed to elucidate the involvement of EVs in MM progression and ascertain whether EV-mediated metastasis promotion persists during single agent BRAF (vemurafenib, dabrafenib), or MEK (trametinib) and combined BRAF/MEK (dabrafenib/trametinib) inhibition.Using five pairs of syngeneic melanoma cell lines, we assessed the impact of EVs - isolated from their respective supernatants - on melanoma cell proliferation and migration. Cell viability and spheroid growth assays were employed to evaluate proliferation, while migration was analyzed through mean squared displacement (MSD) and total traveled distance (TTD) measurements derived from video microscopy and single-cell tracking.Our results indicate that while EV treatments had remarkable promoting effect on cell migration, they exerted only a modest effect on cell proliferation and spheroid growth. Notably, EVs demonstrated the ability to mitigate the inhibitory effects of BRAF inhibitors, albeit they were ineffective against a MEK inhibitor and the combination of BRAF/MEK inhibitors. In summary, our findings contribute to the understanding of the intricate role played by EVs in tumor progression, metastasis, and drug resistance in MM.

Single agent vemurafenib or rituximab-vemurafenib combination for the treatment of relapsed/refractory hairy cell leukemia, a multicenter experience.

BACKGROUND: Hairy cell leukemia (HCL) is a rare mature B-cell malignancy that is primarily treated with purine analogues. However, relapse remains a significant challenge, prompting the search for alternative therapies. The BRAF V600E mutation prevalent in HCL patients provides a target for treatment with vemurafenib. PATIENTS AND METHODS: This multicenter retrospective study included nine patients with relapsed/refractory (R/R) HCL from six different centers. Patient data included demographics, prior treatments, clinical outcomes, and adverse events. RESULTS: Patients received different treatment regimens between centers, including vemurafenib alone or in combination with rituximab. Despite the differences in protocols, all patients achieved at least a partial response, with seven patients achieving a complete response. Adverse events were generally mild with manageable side effects. The absence of myelotoxic effects and manageable side effects make BRAF inhibitors attractive, especially for patients ineligible for purine analogues or those with severe neutropenia. CONCLUSION: Single agent vemurafenib or in combination with rituximab appears to be a promising therapeutic option for R/R HCL. Further research is needed to establish standardized treatment protocols and to investigate long-term outcomes.

Development and in-depth characterization of BRAFi-resistant melanoma cell lines in vitro and in vivo.

Regardless of the clinical response and improved patient survival observed following treatment with BRAFi like Vemurafenib (Vem), rapid development of resistance still remains as a major obstacle in melanoma therapy. In this context, we developed and characterized two acquired Vem-resistant melanoma cell lines, A375V and SK-MEL-28V, and an intrinsically Vem-resistant cell line, RPMI-7951. Altered morphology and growth rate of the resistant cell lines displayed spindle-shaped cells with filopodia formation and enhanced proliferation rate as compared to parental cells. Further in vitro characterization in 2D models confirmed the emergence of a resistant phenotype in melanoma cells. To mimic the in vivo tumor microenvironment, spheroids were developed for both parental and resistant cell lines to recognize materialization of invadopodia structures demonstrating elevated invasiveness and proliferation of resistant cells-based spheroids, especially A375V. Importantly, we validated A375V cell line in vivo to prove its tumorigenicity and drug resistance in tumor xenograft model. Taken together, our established clinically relevant Vem-resistant tumor model could be beneficial to elucidate drug resistance mechanisms, screen and identify novel anticancer therapies to overcome BRAFi resistance in melanoma.

Erdheim-Chester disease as complex clinical presentation and diagnosis: A case report and concise review of literature.

RATIONALE: Erdheim-Chester disease (ECD) is a rare multisystemic disease characterized by the infiltration of multiple organs by foamy CD68 + CD1a-histiocytes. The genetic background consists of gain-of-function somatic mutations in the mitogen-activated protein kinase pathway. The purpose of the present paper is to make a contribution to the scientific literature on ECD by reporting our experience with a complex clinical case report, along with a concise review of the literature. We discussed the unusual clinical presentation, the complex diagnostic process and the comparison with other published cases. PATIENT CONCERNS: A 70-year-old man presented with arthralgia due to multiple bone areas of sclerosis, first diagnosed with metastases of a prostatic neoplasm. Sequential thorax-abdomen, femoral and homer contrast-enhanced computed tomography (CT) showed pericardial effusion, pulmonary fibrosis, and perirenal fibrous tissue as "hairy kidneys." He underwent. Three bone biopsies were unsuccessful to reach diagnosis. DIAGNOSES: A xanthelasma biopsy showed histopathological signs compatible with ECD; genetic analysis showed the mutation BRAFV600E. INTERVENTIONS: The patient underwent targeted therapy with vemurafenib (BRAF-inhibitor), discontinued 2 weeks later due to the onset of a diffuse erythematous papular rash on the trunk and limbs. OUTCOMES: At the 1-year follow-up, there was only progression of chronic kidney disease (CKD). LESSONS: The present case report describes how ECD diagnosis could represent a challenge for clinicians, owing to its heterogeneous clinical presentation. Early diagnosis followed by prompt therapy is essential for modifying the natural history of the disease.

Autophagy sustains mitochondrial respiration and determines resistance to BRAFV600E inhibition in thyroid carcinoma cells.

BRAFV600E is the most prevalent mutation in thyroid cancer and correlates with poor prognosis and therapy resistance. Although selective inhibitors of BRAFV600E have been developed, more advanced tumors such as anaplastic thyroid carcinomas show a poor response in clinical trials. Therefore, the study of alternative survival mechanisms is needed. Since metabolic changes have been related to malignant progression, in this work we explore metabolic dependencies of thyroid tumor cells to exploit them therapeutically. Our results show that respiration of thyroid carcinoma cells is highly dependent on fatty acid oxidation and, in turn, fatty acid mitochondrial availability is regulated through macroautophagy/autophagy. Furthermore, we show that both lysosomal inhibition and the knockout of the essential autophagy gene, ATG7, lead to enhanced lipolysis; although this effect is not essential for survival of thyroid carcinoma cells. We also demonstrate that following inhibition of either autophagy or fatty acid oxidation, thyroid tumor cells compensate oxidative phosphorylation deficiency with an increase in glycolysis. In contrast to lipolysis induction, upon autophagy inhibition, glycolytic boost in autophagy-deficient cells is essential for survival and, importantly, correlates with a higher sensitivity to the BRAFV600E selective inhibitor, vemurafenib. In agreement, downregulation of the glycolytic pathway results in enhanced mitochondrial respiration and vemurafenib resistance. Our work provides new insights into the role of autophagy in thyroid cancer metabolism and supports mitochondrial targeting in combination with vemurafenib to eliminate BRAFV600E-positive thyroid carcinoma cells.Abbreviations: AMP: adenosine monophosphate; ATC: anaplastic thyroid carcinoma; ATG: autophagy related; ATP: adenosine triphosphate; BRAF: B-Raf proto-oncogene, serine/threonine kinase; Cas9: CRISPR-associated protein; CREB: cAMP responsive element binding protein; CRISPR: clustered regularly interspaced short palindromic repeats; 2DG: 2-deoxyglucose; FA: fatty acid; FAO: fatty acid oxidation; FASN: fatty acid synthase; FCCP: trifluoromethoxy carbonyl cyanide phenylhydrazone; LAMP1: lysosomal associated membrane protein 1; LIPE/HSL: lipase E, hormone sensitive type; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; OCR: oxygen consumption rate; OXPHOS: oxidative phosphorylation; PRKA/PKA: protein kinase cAMP-activated; PTC: papillary thyroid carcinoma; SREBF1/SREBP1: sterol regulatory element binding transcription factor 1.

Clinical responses to vemurafenib in postoperative recurrence of papillary thyroid carcinoma with esophageal fistula: A case report.

BACKGROUND: While papillary thyroid carcinoma (PTC) generally exhibits a favorable prognosis post-surgery, the poorly differentiated subtype presents elevated rates of postoperative recurrence. Certain aggressive cases demonstrate invasive behavior, compromising adjacent structures and leading to a poor prognosis. This study delineates a unique case of postoperative PTC recurrence, complicated by esophageal fistula, that showed favorable outcomes following brief Vemurafenib treatment. PATIENT DESCRIPTION: A 64-year-old female patient underwent surgical resection for PTC, subsequently experiencing rapid tumor recurrence and development of an esophageal fistula. DIAGNOSIS: The patient was confirmed to have locally advanced PTC through intraoperative cytopathology. The cancer recurred postoperatively, culminating in the formation of an esophageal fistula. METHODS: The patient was administered Vemurafenib at a dosage of 960 mg twice daily following tumor recurrence. RESULTS: A 12-month regimen of targeted Vemurafenib therapy led to a substantial reduction in tumor size. Concurrently, the esophageal fistula underwent complete healing, facilitating successful removal of the gastrostomy tube. The tumor response was classified as stable disease. CONCLUSION SUBSECTIONS: Vemurafenib demonstrates potential as a targeted therapeutic strategy for recurrent PTC harboring the BRAFV600E mutation. This approach may effectively mitigate tumor dimensions and the associated risk of esophageal and tracheal fistulas.

Promising response to vemurafenib and cobimetinib treatment for BRAF V600E mutated craniopharyngioma: a case report and literature review.

Craniopharyngiomas are tumors that arise from the remnants of Rathke's pouch along the nasopharynx to the diencephalon. Current standard of care includes maximal surgical resection versus adjuvant radiation if a maximal resection is unfeasible. Pharmacological therapy with MAPK targeted agents is an emerging therapeutic option for tumors with BRAF V600E mutations. We report a 45-year-old male with a strictly third ventricle papillary craniopharyngioma with a BRAF V600E mutation. After initial surgery with subtotal resection, the patient demonstrated durable response to targeted BRAF and MEK inhibitor therapy with vemurafenib and cobimetinib. Our report suggests that targeted therapy may reduce the need for radiation and impact surgical interventions in select cases.

Evodiamine inhibits growth of vemurafenib drug-resistant melanoma via suppressing IRS4/PI3K/AKT signaling pathway.

Evodiamine, a novel alkaloid, was isolated from the fruit of tetradium. It exerts a diversity of pharmacological effects and has been used to treat gastropathy, hypertension, and eczema. Several studies reported that evodiamine has various biological effects, including anti-nociceptive, anti-bacterial, anti-obesity, and anti-cancer activities. However, there is no research regarding its effects on drug-resistant cancer. This study aimed to investigate the effect of evodiamine on human vemurafenib-resistant melanoma cells (A375/R cells) proliferation ability and its mechanism. Cell activity was assessed using the cell counting kit-8 (CCK-8) method. Flow cytometry assay was used to assess cell apoptosis and cell cycle. A xenograft model was used to analyze the inhibitory effects of evodiamine on tumor growth. Bioinformatics analyses, network pharmacology, and molecular docking were used to explore the potential mechanism of evodiamine in vemurafenib-resistant melanoma. RT-qPCR and Western blotting were performed to reveal the molecular mechanism. The alkaloid extract of the fruit of tetradium, evodiamine showed the strongest tumor inhibitory effect on vemurafenib-resistant melanoma cells compared to treatment with vemurafenib alone. Evodiamine inhibited vemurafenib-resistant melanoma cell growth, proliferation, and induced apoptosis, conforming to a dose-effect relationship and time-effect relationship. Results from network pharmacology and molecular docking suggested that evodiamine might interact with IRS4 to suppress growth of human vemurafenib-resistant melanoma cells. Interestingly, evodiamine suppressed IRS4 expression and then inhibited PI3K/AKT signaling pathway, and thus had the therapeutic action on vemurafenib-resistant melanoma.

Identification and characterization of stromal-like cells with CD207+/low CD1a+/low phenotype derived from histiocytic lesions - a perspective in vitro model for drug testing.

BACKGROUND: Histiocytoses are rare disorders manifested by increased proliferation of pathogenic myeloid cells sharing histological features with macrophages or dendritic cells and accumulating in various organs, i.a., bone and skin. Pre-clinical in vitro models that could be used to determine molecular pathways of the disease are limited, hence research on histiocytoses is challenging. The current study compares cytophysiological features of progenitor, stromal-like cells derived from histiocytic lesions (sl-pHCs) of three pediatric patients with different histiocytoses types and outcomes. The characterized cells may find potential applications in drug testing. METHODS: Molecular phenotype of the cells, i.e. expression of CD1a and CD207 (langerin), was determined using flow cytometry. Cytogenetic analysis included GTG-banded metaphases and microarray (aCGH) evaluation. Furthermore, the morphology and ultrastructure of cells were evaluated using a confocal and scanning electron microscope. The microphotographs from the confocal imaging were used to reconstruct the mitochondrial network and its morphology. Basic cytophysiological parameters, such as viability, mitochondrial activity, and proliferation, were analyzed using multiple cellular assays, including Annexin V/7-AAD staining, mitopotential analysis, BrdU test, clonogenicity analysis, and distribution of cells within the cell cycle. Biomarkers potentially associated with histiocytoses progression were determined using RT-qPCR at mRNA, miRNA and lncRNA levels. Intracellular accumulation of histiocytosis-specific proteins was detected with Western blot. Cytotoxicyty and IC50 of vemurafenib and trametinib were determined with MTS assay. RESULTS: Obtained cellular models, i.e. RAB-1, HAN-1, and CHR-1, are heterogenic in terms of molecular phenotype and morphology. The cells express CD1a/CD207 markers characteristic for dendritic cells, but also show intracellular accumulation of markers characteristic for cells of mesenchymal origin, i.e. vimentin (VIM) and osteopontin (OPN). In subsequent cultures, cells remain viable and metabolically active, and the mitochondrial network is well developed, with some distinctive morphotypes noted in each cell line. Cell-specific transcriptome profile was noted, providing information on potential new biomarkers (non-coding RNAs) with diagnostic and prognostic features. The cells showed different sensitivity to vemurafenib and trametinib. CONCLUSION: Obtained and characterized cellular models of stromal-like cells derived from histiocytic lesions can be used for studies on histiocytosis biology and drug testing.

Neoadjuvant cobimetinib and atezolizumab with or without vemurafenib for high-risk operable Stage III melanoma: the Phase II NeoACTIVATE trial.

Both targeted therapies and immunotherapies provide benefit in resected Stage III melanoma. We hypothesized that the combination of targeted and immunotherapy given prior to therapeutic lymph node dissection (TLND) would be tolerable and drive robust pathologic responses. In NeoACTIVATE (NCT03554083), a Phase II trial, patients with clinically evident resectable Stage III melanoma received either 12 weeks of neoadjuvant vemurafenib, cobimetinib, and atezolizumab (BRAF-mutated, Cohort A, n = 15), or cobimetinib and atezolizumab (BRAF-wild-type, Cohort B, n = 15) followed by TLND and 24 weeks of adjuvant atezolizumab. Here, we report outcomes from the neoadjuvant portion of the trial. Based on intent to treat analysis, pathologic response (≤50% viable tumor) and major pathologic response (complete or near-complete, ≤10% viable tumor) were observed in 86.7% and 66.7% of BRAF-mutated and 53.3% and 33.3% of BRAF-wild-type patients, respectively (primary outcome); these exceeded pre-specified benchmarks of 50% and 30% for major pathologic response. Grade 3 and higher toxicities, primarily dermatologic, occurred in 63% during neoadjuvant treatment (secondary outcome). No surgical delays nor progression to regional unresectability occurred (secondary outcome). Peripheral blood CD8 + TCM cell expansion associated with favorable pathologic responses (exploratory outcome).

Multisystem Erdheim-Chester disease presenting with pericardial effusion confirmed by the effusion cytology specimen.

Erdheim-Chester disease (ECD) is a rare histiocytosis characterized by the foamy CD68+CD1a- histiocytes infiltrating multiple organs and tissues. ECD might be asymptomatic or present with variable manifestations. The diagnosis of ECD requires characteristic radiological findings and pathological features. Herein, we described a 52-year-old female patient who was admitted to our hospital for recurrent pericardial effusion for two months. She has a medical history of papillary thyroid carcinoma (PTC) and underwent a total thyroidectomy two years before admission. The radiological findings suggested a potential diagnosis of ECD. Cytological analysis of the effusion cytology specimen revealed CD68+CD1a- histiocytes, confirming the ECD diagnosis. The BRAF V600E mutation was identified in the histiocytes, prompting the administration of vemurafenib, a BRAF inhibitor. After two months of standard-dose vemurafenib treatment, the disease was well controlled with pericardial effusion regression.

Survival of patients with unfavorable prognosis cutaneous melanoma with increased use of immunotherapy agents: a population-based study in Belgium.

BACKGROUND: Although metastatic cutaneous melanoma is associated with an unfavorable prognosis, innovative therapies including immunomodulating agents and targeted therapies have shown survival benefits in clinical trials. We assessed the impact of the introduction of innovative drugs into clinical practice on the survival of patients with metastatic cutaneous melanoma during the period 2004-2017, in Belgium. The evolution of associated expenses was also analyzed. METHODS: This is a retrospective population-based study using data from the national Belgian Cancer Registry, compulsory health insurance, and administrative survival data. The immunomodulating drugs were ipilimumab, nivolumab and pembrolizumab, while targeted therapies included vemurafenib, dabrafenib and trametinib. RESULTS: We did not identify a trend for improvement over time. Median survival (years) was 1.5 (95% CI: 1.1-1.8) in 2004-2008, 1.1 (95% CI: 0.8-1.5) in 2009-2013, and 1.6 (95% CI: 1.3-2.4) in 2014-2017, respectively. In contrast, survival improved in those with unknown primary tumor localization. In this group, median survival time was 2.0 (95% CI: 1.4-2.9) in the most recent period, while it was 1.1 (95% CI: 0.7-1.3) in 2009-2013, and 0.9 (95% CI: 0.6-1.2) in 2004-2008. The uptake of innovative drugs remained modest, with no drug being used by more than 30% of patients. Yearly expenditure was almost non-existent, and gradually increased, reaching several million euros in 2014-2017. CONCLUSION: Patients with metastatic cutaneous melanoma who were diagnosed between 2004 and 2017 showed no apparent improvement in survival. In contrast, increased survival was observed in the subgroup of patients with unknown primary tumor localization.