Proteome Analysis Identified the PPARγ Ligand 15d-PGJ2 as a Novel Drug Inhibiting Melanoma Progression and Interfering with Tumor-Stroma Interaction

Berger

Molecular Cancer Therapeutics

et al. 2015

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The FDA-approved BRAF inhibitor vemurafenib achieves outstanding clinical response rates in patients with melanoma, but early resistance is common. Understanding the pathologic mechanisms of drug resistance and identification of effective therapeutic alternatives are key scientific challenges in the melanoma setting. Using proteomic techniques, including shotgun analysis and 2D-gel electrophoresis, we identified a comprehensive signature of the vemurafenib-resistant M24met in comparison with the vemurafenib-sensitive A375 melanoma cell line. The resistant cells were characterized by loss of differentiation, induction of transformation, enhanced expression of the lysosomal compartment, increased potential for metastasis, migration, adherence and Ca2(+) ion binding, enhanced expression of the MAPK pathway and extracellular matrix proteins, and epithelial-mesenchymal transformation. The main features were verified by shotgun analysis with QEXACTIVE orbitrap MS, electron microscopy, lysosomal staining, Western blotting, and adherence assay in a VM-1 melanoma cell line with acquired vemurafenib resistance. On the basis of the resistance profile, we were able to successfully predict that a novel resveratrol-derived COX-2 inhibitor, M8, would be active against the vemurafenib-resistant but not the vemurafenib-sensitive melanoma cells. Using high-throughput methods for cell line and drug characterization may thus offer a new way to identify key features of vemurafenib resistance, facilitating the design of effective rational therapeutic alternatives.

Section: Cell Line and Chemicalsmentioning

confidence: 99%

Vemurafenib Resistance Signature by Proteome Analysis Offers New Strategies and Rational Therapeutic Concepts

Berger

Molecular Cancer Therapeutics

et al. 2015

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“…The zymography assay was performed as described previously (Paulitschke et al, 2012). The supernatants of the primary cells were collected.…”

Section: Zymography Assaymentioning

confidence: 99%

“…Proteome analysis was performed as described previously (Paulitschke et al, 2012(Paulitschke et al, , 2013.…”

Section: Proteome Analysismentioning

confidence: 99%

Proteomic identification of a marker signature for MAPK i resistance in melanoma

et al. 2019

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MAPK inhibitors (MAPKi) show outstanding clinical response rates in melanoma patients harbouring BRAF mutations, but resistance is common. The ability of melanoma cells to switch from melanocytic to mesenchymal phenotypes appears to be associated with therapeutic resistance. High‐throughput, subcellular proteome analyses and RNAseq on two panels of primary melanoma cells that were either sensitive or resistant to MAPKi revealed that only 15 proteins were sufficient to distinguish between these phenotypes. The two proteins with the highest discriminatory power were PTRF and IGFBP7, which were both highly upregulated in the mesenchymal‐resistant cells. Proteomic analysis of CRISPR/Cas‐derived PTRF knockouts revealed targets involved in lysosomal activation, endocytosis, pH regulation, EMT, TGFβ signalling and cell migration and adhesion, as well as a significantly reduced invasive index and ability to form spheres in 3D culture. Overexpression of PTRF led to MAPKi resistance, increased cell adhesion and sphere formation. In addition, immunohistochemistry of patient samples showed that PTRF expression levels were a significant biomarker of poor progression‐free survival, and IGFBP7 levels in patient sera were shown to be higher after relapse.

Annals of the New York Academy of Sciences

“…79,80 Although controversial, 4 the J2 prostaglandins 15d-PGJ2 and 12-PGJ2 are considered to be endogenous ligands for the nuclear peroxisomal proliferator activator receptor (PPAR␥ ), to which they bind with high affinity. 81,82 PPAR␥ activation in the nucleus plays a major role in the regulation of adipogenesis, glucose homeostasis, cellular differentiation, apoptosis, and inflammation. 83 PPAR␥ agonists, such as the J2 prostaglandins, promote neuroprotection in models of stroke, AD, HD, PD, multiple sclerosis, and spinal cord injury, via anti-inflammatory or antioxidant-dependent mechanisms.…”

Section: Why Investigate the Role Of Pgj2?mentioning

confidence: 99%

Prostaglandin J2: a potential target for halting inflammation‐induced neurodegeneration

Figueiredo‐Pereira

Corwin

Babich

2016

Prostaglandins are produced via cyclooxygenases, which are enzymes that play a major role in neuroinflammation. Epidemiological studies show that chronic treatment with low levels of cyclooxygenase inhibitors (NSAIDs) lowers the risk for Alzheimer's (AD) and Parkinson's (PD) diseases by as much as 50%. Unfortunately, inhibiting cyclooxygenases with NSAIDs blocks the synthesis of downstream neuroprotective and neurotoxic prostaglandins, thus producing adverse side effects. We focus on prostaglandin J2 (PGJ2) because it is highly neurotoxic compared to PGA1, D2, and E2. Unlike other prostaglandins, PGJ2 and its metabolites have a cyclopentenone ring with reactive α,β-unsaturated carbonyl groups that form covalent Michael adducts with key cysteines in proteins and GSH. Cysteine-binding electrophiles such as PGJ2 are considered to play an important role in determining whether neurons will live or die. We discuss in vitro and in vivo studies showing that PGJ2 induces pathological processes relevant to neurodegenerative disorders such as AD and PD. Furthermore, we found that increasing intracellular cAMP with the lipophilic peptide PACAP27 counteracts some of the PGJ2-induced detrimental effects. In conclusion, new therapeutic strategies that neutralize the effects of specific neurotoxic prostaglandins downstream from cyclooxygenases could have a significant impact on the treatment of chronic neurodegenerative disorders with fewer adverse side effects.