Metastatic melanoma cells with BRAF G469A mutation: nab-paclitaxel better than vemurafenib?

BRAF mutation in myeloid neoplasm: incidences and clinical outcomes

The presence of BRAF mutation in hematological malignancies, excluding Hairy cell leukemia, and its significance as a driver mutation in myeloid neoplasms (MNs) remains largely understudied. This research aims to evaluate patient characteristics and outcomes of BRAF-mutated MNs. Among a cohort of 6667 patients, 48 (0.7%) had BRAF-mutated MNs. Notably, three patients exhibited sole BRAF mutation, providing evidence supporting the hypothesis of BRAF's role as a driver mutation in MNs. In acute myeloid leukemia, the majority of patients had secondary acute myeloid leukemia, accompanied by poor-risk cytogenic and RAS pathway mutations. Although the acquisition of BRAF mutation during disease progression did not correlate with unfavorable outcomes, its clearance through chemotherapy or stem cell transplant exhibited favorable outcomes (median overall survival of 34.8 months versus 10.4 months, p = 0.047). Furthermore, G469A was the most frequently observed BRAF mutation, differing from solid tumors and hairy cell leukemia, where V600E mutations were predominant.

Extracellular Matrix Collagen I Differentially Regulates the Metabolic Plasticity of Pancreatic Ductal Adenocarcinoma Parenchymal Cell and Cancer Stem Cell

Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival rate of less than 10 percent largely due to the intense fibrotic desmoplastic reaction, characterized by high levels of extracellular matrix (ECM) collagen I that constitutes a niche for a subset of cancer cells, the cancer stem cells (CSCs). Cancer cells undergo a complex metabolic adaptation characterized by changes in metabolic pathways and biosynthetic processes. The use of the 3D organotypic model in this study allowed us to manipulate the ECM constituents and mimic the progression of PDAC from an early tumor to an ever more advanced tumor stage. To understand the role of desmoplasia on the metabolism of PDAC parenchymal (CPC) and CSC populations, we studied their basic metabolic parameters in organotypic cultures of increasing collagen content to mimic in vivo conditions. We further measured the ability of the bioenergetic modulators (BMs), 2-deoxyglucose, dichloroacetate and phenformin, to modify their metabolic dependence and the therapeutic activity of paclitaxel albumin nanoparticles (NAB-PTX). While all the BMs decreased cell viability and increased cell death in all ECM types, a distinct, collagen I-dependent profile was observed in CSCs. As ECM collagen I content increased (e.g., more aggressive conditions), the CSCs switched from glucose to mostly glutamine metabolism. All three BMs synergistically potentiated the cytotoxicity of NAB-PTX in both cell lines, which, in CSCs, was collagen I-dependent and the strongest when treated with phenformin + NAB-PTX. Metabolic disruption in PDAC can be useful both as monotherapy or combined with conventional drugs to more efficiently block tumor growth.

NGS based identification of mutational hotspots for targeted therapy in anaplastic thyroid carcinoma

CONTEXT

Anaplastic thyroid carcinoma (ATC) represents one of the most aggressive carcinomas with no consistent survival benefit when treated with conventional radiochemotherapy. Approaches targeting "oncogene addiction" of ATC are increasingly explored and first promising results have been reported in single case studies.

OBJECTIVE

To determine the prevalence of mutations in known thyroid oncogenes and signalling pathways amendable to targeted therapy in a large cohort of ATC.

RESULTS

In 118 ATC (57 male/ 61 female) a total of 165 mutations were found. Genes involved in the MAPK/ERK and PI3K pathway (BRAF 11.0%, HRAS 4.2%, KRAS 7.6%, NRAS 7.6%, PI3KCA 11.8%) were altered in 33%. Targetable receptor tyrosine kinases were mutated in 11%. The most frequently altered genes were TERT in 86/118 (73%) and p53 in 65/118 (55%) cases. No mutations were found analysing ALK, KIT, MET and mTOR.

MATERIALS AND METHODS

Next generation sequencing (NGS) was performed in FFPE samples from 118 ATC using MiSeq (Illumina) and CLC Cancer Research Workbench (CLCbio; Qiagen) for mutation analysis in: ALK, BRAF, CDKN2A, EGFR, ERBB2, HRAS, KIT, KRAS, MET, mTOR, NRAS, PDGFRA, PI3KCA, p53, RB1, RET and TSC2. Sanger sequencing was used to detect TERT promotor mutations.

CONCLUSIONS

To our knowledge this is the largest study analysing mutations for targeted therapy of ATC. We found that 33% of ATC harbour mutations in pathways amendable to targeted therapy. Molecular screening in ATC is suggested for targeted therapies since current conventional treatment for ATC proved mainly futile.

Mitogen-Activated Protein Kinase Signaling Pathway in Cutaneous Melanoma: An Updated Review

The mitogen-activated protein kinase (MAPK) signaling pathway is a cascade of protein kinases that act in a sequential and predominantly linear fashion, albeit displaying some cross talk with other signaling cascades. Mutations in proteins integral to the MAPK signaling pathway are present in more than 50% of cutaneous melanomas. The most frequently mutated protein is v-raf murine sarcoma viral oncogene homolog B (BRAF), followed by neuroblastoma Ras viral oncogene homolog (NRAS). Recently, the development of targeted drugs for the treatment of BRAF-mutant melanoma has led to the widespread implementation of molecular assays for the detection of specific BRAF mutations. There have been some attempts to standardize testing of BRAF mutations, but this has not been achieved so far. Here we provide an updated review on the role of the MAPK signaling pathway in the pathogenesis of cutaneous melanoma, focusing on several different BRAF mutations and their diagnostic and therapeutic implications.

Vulvar and vaginal melanoma: A unique subclass of mucosal melanoma based on a comprehensive molecular analysis of 51 cases compared with 2253 cases of nongynecologic melanoma

BACKGROUND

Optimal treatments for vulvar and vaginal melanomas (VVMs) have not been identified. Herein, the authors compare molecular profiles between VVM and nongynecologic melanoma (NGM) subtypes with the objective of identifying novel, targetable biomarkers.

METHODS

In total, 2304 samples of malignant melanoma that were submitted to Caris Life Sciences between 2009 and 2015 were reviewed. In situ hybridization and immunohistochemistry were used to assess copy numbers and protein expression of selected genes. Sequenced variants were analyzed using a proprietary cancer panel.

RESULTS

In total, 51 VVMs (14 vaginal and 37 vulvar melanomas) were compared with 2253 malignant NGMs, including 2127 cutaneous, 105 mucosal, and 21 acral melanomas. In VVMs, B-Raf proto-oncogene serine/threonine kinase (BRAF) was the most frequently mutated gene (26%) compared with 8.3% of mucosal NGMs (P = .008). In BRAF-mutated tumors, fewer VVMs (50%), compared with NGMs (82.1%), had a variant within the valine codon 600 (V600) domain. The KIT mutation rate was highest in VVMs (22%) compared with 3% in cutaneous (P < .001) and 8.8% in mucosal (P = .05) melanoma subtypes. NRAS mutations were rare in VVMs compared with cutaneous (25.9%; P = .009) and acral (40.6%; P = .002) melanoma subtypes. PD-L1 (56%) and PD-1 (75%) were frequently expressed in VVM, whereas PI3KCA pathway mutations and estrogen receptor/progesterone receptor expression were rare. Compared with VVMs that had KIT mutations, wild-type KIT VVMs were more likely to express molecular markers suggestive of platinum resistance (ERCC1), alkylating sensitivity (MGMT), and anthracycline sensitivity (TOP2A).

CONCLUSIONS

The unique molecular features of VVM render this disease a distinct subtype of melanoma. Gene-based molecular therapy and immunotherapies may be promising and should be evaluated in clinical trials. Cancer 2017;123:1333-1344. © 2016 American Cancer Society.

Synthesis, Characterization, and Cytotoxicity of the First Oxaliplatin Pt(IV) Derivative Having a TSPO Ligand in the Axial Position

The first Pt(IV) derivative of oxaliplatin carrying a ligand for TSPO (the 18-kDa mitochondrial translocator protein) has been developed. The expression of the translocator protein in the brain and liver of healthy humans is usually low, oppositely to steroid-synthesizing and rapidly proliferating tissues, where TSPO is much more abundant. The novel Pt(IV) complex, cis,trans,cis-[Pt(ethanedioato)Cl{2-(2-(4-(6,8-dichloro-3-(2-(dipropylamino)-2-oxoethyl)imidazo[1,2-a]pyridin-2-yl)phenoxy)acetate)-ethanolato}(1R,2R-DACH)] (DACH = diaminocyclohexane), has been fully characterized by spectroscopic and spectrometric techniques and tested in vitro against human MCF7 breast carcinoma, U87 glioblastoma, and LoVo colon adenocarcinoma cell lines. In addition, affinity for TSPO (IC50 = 18.64 nM), cellular uptake (ca. 2 times greater than that of oxaliplatin in LoVo cancer cells, after 24 h treatment), and perturbation of cell cycle progression were investigated. Although the new compound was less active than oxaliplatin and did not exploit a synergistic proapoptotic effect due to the presence of the TSPO ligand, it appears to be promising in a receptor-mediated drug targeting context towards TSPO-overexpressing tumors, in particular colorectal cancer (IC50 = 2.31 μM after 72 h treatment).

Targeting oncogenic BRAF and aberrant MAPK activation in the treatment of cutaneous melanoma

BRAF and MEK inhibitors, alone or in combination, are highly active in the 40% of patients with BRAF mutant metastatic melanoma. Despite this activity resistance often develops in patients treated with these agents. This review summarises the biology of the mitogen activated protein kinase (MAPK) pathway, with particular reference to the effects of BRAF and MEK inhibitors in BRAF mutant melanoma. The clinical and molecular predictors of response and mechanisms of resistance are discussed in detail along with the biological rationale and evidence for future treatment strategies in both MAPK inhibitor naïve and resistant BRAF mutant melanoma.