Cutting-Edge Technologies Driving Quantitative Mass Spectrometry.

Correa, C. N., Fiametti, L.

CRISPR/dCas9-KRAB-Mediated Suppression of Restores p53-Mediated Apoptosis in Melanoma Cells.

Overexpression of S100B is routinely used for disease-staging and for determining prognostic outcomes in patients with malignant melanoma. Intracellular interactions between S100B and wild-type (WT)-p53 have been demonstrated to limit the availability of free WT-p53 in tumor cells, inhibiting the apoptotic signaling cascade. Herein, we demonstrate that, while oncogenic overexpression of is poorly correlated (R < 0.

Raman Spectroscopy and Machine Learning Reveals Early Tumor Microenvironmental Changes Induced by Immunotherapy.

Cancer immunotherapy provides durable clinical benefit in only a small fraction of patients, and identifying these patients is difficult due to a lack of reliable biomarkers for prediction and evaluation of treatment response. Here, we demonstrate the first application of label-free Raman spectroscopy for elucidating biomolecular changes induced by anti-CTLA4 and anti-PD-L1 immune checkpoint inhibitors (ICI) in the tumor microenvironment (TME) of colorectal tumor xenografts. Multivariate curve resolution-alternating least squares (MCR-ALS) decomposition of Raman spectral datasets revealed early changes in lipid, nucleic acid, and collagen content following therapy.

Quantitative Histone Mass Spectrometry Identifies Elevated Histone H3 Lysine 27 (Lys27) Trimethylation in Melanoma.

Normal cell growth is characterized by a regulated epigenetic program that drives cellular activities such as gene transcription, DNA replication, and DNA damage repair. Perturbation of this epigenetic program can lead to events such as mis-regulation of gene transcription and diseases such as cancer. To begin to understand the epigenetic program correlated to the development of melanoma, we performed a novel quantitative mass spectrometric analysis of histone post-translational modifications mis-regulated in melanoma cell culture as well as patient tumors.

Proteomics-Based Identification of Differentially Abundant Proteins from Human Keratinocytes Exposed to Arsenic Trioxide.

Introduction: Arsenic is a widely distributed environmental toxicant that can cause multi-tissue pathologies. Proteomic assays allow for the identification of biological processes modulated by arsenic in diverse tissue types.

Method: The altered abundance of proteins from HaCaT human keratinocyte cell line exposed to arsenic was quantified using a label-free LC-MS/MS mass spectrometry workflow.

Quantitative Proteomics Identifies Activation of Hallmark Pathways of Cancer in Patient Melanoma.

Molecular pathways regulating melanoma initiation and progression are potential targets of therapeutic development for this aggressive cancer. Identification and molecular analysis of these pathways in patients has been primarily restricted to targeted studies on individual proteins. Here, we report the most comprehensive analysis of formalin-fixed paraffin-embedded human melanoma tissues using quantitative proteomics.

Misregulation of Rad50 expression in melanoma cells.

DNA double-strand breaks are increased in human melanoma tissue as detected by histone H2AX phosphorylation.(1-3) We investigated two of the downstream effectors of DNA double-strand breaks, Rad50 and 53BP1 (tumor suppressor p53 binding protein 1), to determine if they are altered in human primary melanoma cells. Melanoma cases showed high Rad50 staining (81.

Application of MassSQUIRM for quantitative measurements of lysine demethylase activity.

Recently, epigenetic regulators have been discovered as key players in many different diseases (1-3). As a result, these enzymes are prime targets for small molecule studies and drug development( 4). Many epigenetic regulators have only recently been discovered and are still in the process of being classified.

MassSQUIRM: An assay for quantitative measurement of lysine demethylase activity.

In eukaryotes, DNA is wrapped around proteins called histones and is condensed into chromatin. Post-translational modification of histones can result in changes in gene expression. One of the most well-studied histone modifications is the methylation of lysine 4 on histone H3 (H3K4).