Distinct Mutation Patterns Reveal Melanoma Subtypes and Influence Immunotherapy Response in Advanced Melanoma Patients
CANCERS
Authors: Hilke, Franz J.; Sinnberg, Tobias; Gschwind, Axel; Niessner, Heike; Demidov, German; Amaral, Teresa; Ossowski, Stephan; Bonzheim, Irina; Roecken, Martin; Riess, Olaf; Garbe, Claus; Schroeder, Christopher; Forschner, Andrea
Abstract
The detection of somatic driver mutations by next-generation sequencing (NGS) is becoming increasingly important in the care of advanced melanoma patients. In our study, we evaluated the NGS results of 82 melanoma patients from clinical routine in 2017. Besides determining the tumor mutational burden (TMB) and annotation of all genetic driver alterations, we investigated their potential as a predictor for resistance to immune checkpoint inhibitors (ICI) and as a distinguishing feature between melanoma subtypes. Melanomas of unknown primary had a similar mutation pattern and TMB to cutaneous melanoma, which hints at its cutaneous origin. Besides the typical hotspot mutation in BRAF and NRAS, we frequently observed CDKN2A deletions. Acral and mucosal melanomas were dominated by CNV alterations affecting PDGFRA, KIT, CDK4, RICTOR, CCND2 and CHEK2. Uveal melanoma often had somatic SNVs in GNA11/Q and amplification of MYC in all cases. A significantly higher incidence of BRAF V600 mutations and EGFR amplifications, PTEN and TP53 deletions was found in patients with disease progression while on ICI. Thus, NGS might help to characterize melanoma subtypes more precisely and to identify possible resistance mechanisms to ICI therapy. Nevertheless, NGS based studies, including larger cohorts, are needed to support potential genetic ICI resistance mechanisms.
Acute and chronic lithium treatment increases Wnt/beta-catenin transcripts in cortical and hippocampal tissue at therapeutic concentrations in mice
METABOLIC BRAIN DISEASE
Authors: De-Paula, Vanessa J.; dos Santos, Carla Cristine C.; Luque, Maria Carolina A.; Ali, Taccyana M.; Kalil, Jorge E.; Forlenza, Orestes V.; Cunha-Neto, Edecio
Abstract
Lithium activates Wnt/beta-catenin signaling leading to stabilization of free cytosolic beta-catenin. The aim of the present study is to evaluate the in vivo effect of acute and chronic lithium treatment on the expression of beta-catenin target genes, addressing its transcripts HIG2, Bcl-xL, Cyclin D1, c-myc, in cortical and hippocampal tissue from adult mice. Lithium doses were established to yield therapeutic working concentrations. In acute treatment, mice received a 300 mu L of a 350 mg/kg solution of LiCl by gavage, and were euthanized after 2 h, 6 h and 12 h. To determine the effect of chronic treatment, animals were continuously fed either with chow supplemented with 2 g/kg Li2CO3, or regular chow (controls), being euthanized after 30 days. All animals had access to drinking water and 0.9% saline ad libitum. After acute and chronic treatments samples of peripheral blood were obtained from the tail vein for each animal, and serum concentrations of lithium were determined. All transcripts were up-regulated in cortical and hippocampal tissues of lithium-treated mice, both under acute and chronic treatments. There was a positive correlation between serum lithium concentrations and the increment in the expression of all transcripts. This effect was observed in all time points of the acute treatment (i.e., 2, 6 and 12 hours) and also after 30 days. We conclude that Wnt/beta-catenin transcriptional response (HIG2, Bcl-xL, Cyclin D1 and c-myc) is up-regulated in the mouse brain in response to acute and chronic lithium treatment at therapeutic concentrations.