MAPK pathway inhibition in melanoma: resistance three ways

2014 ◽  
Vol 42 (4) ◽  
pp. 727-732 ◽  
Author(s):  
Claudia Wellbrock
Keyword(s):  
Mapk Pathway ◽  
Acquired Resistance ◽  
Tumour Microenvironment ◽  
Resistance Mechanisms ◽  
Melanoma Cells ◽  
Advanced Melanoma ◽  
Mitogen Activated Protein Kinase ◽  
Compensatory Mechanisms ◽  
Stromal Fibroblasts ◽  
Paracrine Signalling

The serine threonine kinases BRAF and MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] are major regulators of the ERK/MAPK pathway, which is deregulated in the majority of melanomas. Targeting BRAF is an effective therapy for advanced melanoma, but patients progress due to the development of resistance. This ‘acquired resistance’ is thought to be based on a minority of tumour cell populations that are resistant and will eventually re-establish tumour growth even in the presence of drug. In particular, mutations, amplifications or overexpression of genes encoding regulators of the MAPK pathway can confer this resistance, because it allows the melanoma cells to bypass inhibitor action by stimulating ERK activation through alternative routes. Furthermore, there are mechanisms that produce resistance by enhancing the tolerance of melanoma cells to the cytotoxic effects of the drug. These compensatory mechanisms can activate survival signals in the melanoma cells without reactivating ERK. Besides these cell-autonomous resistance mechanisms, stromal fibroblasts in the tumour microenvironment have been identified as a potential source of resistance, because these cells can produce growth factors that reactivate ERK through paracrine signalling. Understanding and further identifying mechanisms of resistance is crucial for the future treatment of advanced melanoma, because this can inform the design of improved therapies with more durable responses.

scholarly journals DDRE-07. DIPG HARBOUR ALTERATIONS TARGETABLE BY MEK INHIBITORS, WITH ACQUIRED RESISTANCE MECHANISMS OVERCOME BY COMBINATORIAL INHIBITION

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii62-ii62
Author(s):  
Elisa Izquierdo ◽  
Diana Carvalho ◽  
Alan Mackay ◽  
Sara Temelso ◽  
Jessica K R Boult ◽  
...  
Keyword(s):  
Drug Exposure ◽  
Mapk Pathway ◽  
Synergistic Effects ◽  
Acquired Resistance ◽  
Mek Inhibitor ◽  
Resistance Mechanisms ◽  
Genetic Alterations ◽  
Mesenchymal Transition

Abstract The survival of children with diffuse intrinsic pontine glioma (DIPG) remains dismal, with new treatments desperately needed. In the era of precision medicine, targeted therapies represent an exciting treatment opportunity, yet resistance can rapidly emerge, playing an important role in treatment failure. In a prospective biopsy-stratified clinical trial, we combined detailed molecular profiling (methylation BeadArray, exome, RNAseq, phospho-proteomics) linked to drug screening in newly-established patient-derived models of DIPG in vitro and in vivo. We identified a high degree of in vitro sensitivity to the MEK inhibitor trametinib (GI50 16-50nM) in samples, which harboured genetic alterations targeting the MAPK pathway, including the non-canonical BRAF_G469V mutation, and those affecting PIK3R1 and NF1. However, treatment of PDX models and of a patient with trametinib at relapse failed to elicit a significant response. We generated trametinib-resistant clones (62-188-fold, GI50 2.4–5.2µM) in the BRAF_G469V model through continuous drug exposure, and identified acquired mutations in MEK1/2 (MEK1_K57N, MEK1_I141S and MEK2_I115N) with sustained pathway up-regulation. These cells showed the hallmarks of mesenchymal transition, and expression signatures overlapping with inherently trametinib-insensitive primary patient-derived cells that predicted an observed sensitivity to dasatinib. Combinations of trametinib with dasatinib and the downstream ERK inhibitor ulixertinib showed highly synergistic effects in vitro. These data highlight the MAPK pathway as a therapeutic target in DIPG, and show the importance of parallel resistance modelling and rational combinatorial treatments likely to be required for meaningful clinical translation.

scholarly journals Oxidative Stress-Related Mechanisms in Melanoma and in the Acquired Resistance to Targeted Therapies

Antioxidants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1942
Author(s):  
Stefania Pizzimenti ◽  
Simone Ribero ◽  
Marie Angele Cucci ◽  
Margherita Grattarola ◽  
Chiara Monge ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Targeted Therapies ◽  
Current Knowledge ◽  
Mapk Pathway ◽  
Acquired Resistance ◽  
Genetic Alterations ◽  
Advanced Melanoma ◽  
Braf Mutations ◽  
Downstream Signaling ◽  
Activating Mutations

Melanoma is a highly aggressive cancer with the poorest prognosis, representing the deadliest form of skin cancer. Activating mutations in BRAF are the most frequent genetic alterations, present in approximately 50% of all melanoma cases. The use of specific inhibitors towards mutant BRAF variants and MEK, a downstream signaling target of BRAF in the MAPK pathway, has significantly improved progression-free and overall survival in advanced melanoma patients carrying BRAF mutations. Nevertheless, despite these improvements, resistance still develops within the first year of therapy in around 50% of patients, which is a significant problem in managing BRAF-mutated advanced melanoma. Understanding these mechanisms is one of the mainstreams of the research on BRAFi/MEKi acquired resistance. Both genetic and epigenetic mechanisms have been described. Moreover, in recent years, oxidative stress has emerged as another major force involved in all the phases of melanoma development, from initiation to progression until the onsets of the metastatic phenotype and chemoresistance, and has thus become a target for therapy. In the present review, we discuss the current knowledge on oxidative stress and its signaling in melanoma, as well as the oxidative stress-related mechanisms in the acquired resistance to targeted therapies.

scholarly journals An adaptive signaling network in melanoma inflammatory niches confers tolerance to MAPK signaling inhibition

2017 ◽  
Vol 214 (6) ◽  
pp. 1691-1710 ◽  
Author(s):  
Helen L. Young ◽  
Emily J. Rowling ◽  
Mattia Bugatti ◽  
Emanuele Giurisato ◽  
Nadia Luheshi ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Acquired Resistance ◽  
Drug Tolerance ◽  
Mapk Signaling ◽  
Signaling Network ◽  
Mitogen Activated Protein Kinase ◽  
Cytokine Signaling ◽  
Adaptive Responses ◽  
Mapk Inhibitors

Mitogen-activated protein kinase (MAPK) pathway antagonists induce profound clinical responses in advanced cutaneous melanoma, but complete remissions are frustrated by the development of acquired resistance. Before resistance emerges, adaptive responses establish a mutation-independent drug tolerance. Antagonizing these adaptive responses could improve drug effects, thereby thwarting the emergence of acquired resistance. In this study, we reveal that inflammatory niches consisting of tumor-associated macrophages and fibroblasts contribute to treatment tolerance through a cytokine-signaling network that involves macrophage-derived IL-1β and fibroblast-derived CXCR2 ligands. Fibroblasts require IL-1β to produce CXCR2 ligands, and loss of host IL-1R signaling in vivo reduces melanoma growth. In tumors from patients on treatment, signaling from inflammatory niches is amplified in the presence of MAPK inhibitors. Signaling from inflammatory niches counteracts combined BRAF/MEK (MAPK/extracellular signal–regulated kinase kinase) inhibitor treatment, and consequently, inhibiting IL-1R or CXCR2 signaling in vivo enhanced the efficacy of MAPK inhibitors. We conclude that melanoma inflammatory niches adapt to and confer drug tolerance toward BRAF and MEK inhibitors early during treatment.

scholarly journals Dissecting Mechanisms of Melanoma Resistance to BRAF and MEK Inhibitors Revealed Genetic and Non-Genetic Patient- and Drug-Specific Alterations and Remarkable Phenotypic Plasticity

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 142 ◽  
Author(s):  
Mariusz L. Hartman ◽  
Malgorzata Sztiller-Sikorska ◽  
Anna Gajos-Michniewicz ◽  
Malgorzata Czyz
Keyword(s):  
Phenotypic Plasticity ◽  
Cell Lines ◽  
Mapk Pathway ◽  
Acquired Resistance ◽  
Resistance Mechanisms ◽  
Genetic Alterations ◽  
Resistant Cell ◽  
Cross Resistance ◽  
Preclinical Model ◽  
Development Of Resistance

The clinical benefit of MAPK pathway inhibition in BRAF-mutant melanoma patients is limited by the development of acquired resistance. Using drug-naïve cell lines derived from tumor specimens, we established a preclinical model of melanoma resistance to vemurafenib or trametinib to provide insight into resistance mechanisms. Dissecting the mechanisms accompanying the development of resistance, we have shown that (i) most of genetic and non-genetic alterations are triggered in a cell line- and/or drug-specific manner; (ii) several changes previously assigned to the development of resistance are induced as the immediate response to the extent measurable at the bulk levels; (iii) reprogramming observed in cross-resistance experiments and growth factor-dependence restricted by the drug presence indicate that phenotypic plasticity of melanoma cells largely contributes to the sustained resistance. Whole-exome sequencing revealed novel genetic alterations, including a frameshift variant of RBMX found exclusively in phospho-AKThigh resistant cell lines. There was no similar pattern of phenotypic alterations among eleven resistant cell lines, including expression/activity of crucial regulators, such as MITF, AXL, SOX, and NGFR, which suggests that patient-to-patient variability is richer and more nuanced than previously described. This diversity should be considered during the development of new strategies to circumvent the acquired resistance to targeted therapies.

scholarly journals Celecoxib as a Valuable Adjuvant in Cutaneous Melanoma Treated with Trametinib

2021 ◽  
Vol 22 (9) ◽  
pp. 4387
Author(s):  
Diana Valentina Tudor ◽  
Ioana Bâldea ◽  
Diana Elena Olteanu ◽  
Eva Fischer-Fodor ◽  
Virag Piroska ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Human Fibroblasts ◽  
In Vitro Study ◽  
Melanoma Cells ◽  
Mitogen Activated Protein Kinase ◽  
Culture Cells ◽  
Nm Range

Background: Melanoma patients stop responding to targeted therapies mainly due to mitogen activated protein kinase (MAPK) pathway re-activation, phosphoinositide 3 kinase/the mechanistic target of rapamycin (PI3K/mTOR) pathway activation or stromal cell influence. The future of melanoma treatment lies in combinational approaches. To address this, our in vitro study evaluated if lower concentrations of Celecoxib (IC50 in nM range) could still preserve the chemopreventive effect on melanoma cells treated with trametinib. Materials and Methods: All experiments were conducted on SK-MEL-28 human melanoma cells and BJ human fibroblasts, used as co-culture. Co-culture cells were subjected to a celecoxib and trametinib drug combination for 72 h. We focused on the evaluation of cell death mechanisms, melanogenesis, angiogenesis, inflammation and resistance pathways. Results: Low-dose celecoxib significantly enhanced the melanoma response to trametinib. The therapeutic combination reduced nuclear transcription factor (NF)–kB (p < 0.0001) and caspase-8/caspase-3 activation (p < 0.0001), inhibited microphthalmia transcription factor (MITF) and tyrosinase (p < 0.05) expression and strongly down-regulated the phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway more significantly than the control or trametinib group (p < 0.0001). Conclusion: Low concentrations of celecoxib (IC50 in nM range) sufficed to exert antineoplastic capabilities and enhanced the therapeutic response of metastatic melanoma treated with trametinib.

scholarly journals Identification of pathways modulating vemurafenib resistance in melanoma cells via a genome-wide CRISPR/Cas9 screen

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Corinna Jie Hui Goh ◽  
Jin Huei Wong ◽  
Chadi El Farran ◽  
Ban Xiong Tan ◽  
Cynthia R Coffill ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Enrichment Analysis ◽  
Melanoma Cells ◽  
Mitogen Activated Protein Kinase ◽  
Braf V600e ◽  
Genome Wide ◽  
A Genome ◽  
Mitogen Activated Protein ◽  
Genome Scale

Abstract Vemurafenib is a BRAF kinase inhibitor (BRAFi) that is used to treat melanoma patients harboring the constitutively active BRAF-V600E mutation. However, after a few months of treatment patients often develop resistance to vemurafenib leading to disease progression. Sequence analysis of drug-resistant tumor cells and functional genomic screens has identified several genes that regulate vemurafenib resistance. Reactivation of mitogen-activated protein kinase (MAPK) pathway is a recurrent feature of cells that develop resistance to vemurafenib. We performed a genome-scale CRISPR-based knockout screen to identify modulators of vemurafenib resistance in melanoma cells with a highly improved CRISPR sgRNA library called Brunello. We identified 33 genes that regulate resistance to vemurafenib out of which 14 genes have not been reported before. Gene ontology enrichment analysis showed that the hit genes regulate histone modification, transcription and cell cycle. We discuss how inactivation of hit genes might confer resistance to vemurafenib and provide a framework for follow-up investigations.

scholarly journals A screen for combination therapies inBRAF/NRASwild type melanoma identifies nilotinib plus MEK inhibitor as a synergistic combination

2017 ◽  
Author(s):  
Marco Ranzani ◽  
Kristel Kemper ◽  
Magali Michaut ◽  
Oscar Krijgsman ◽  
Nanne Aben ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Acquired Resistance ◽  
Mek Inhibitor ◽  
Resistance Mechanisms ◽  
Wild Type ◽  
Genome Wide ◽  
Melanoma Patients ◽  
Inhibitor Combination

AbstractDespite recent therapeutic advances in the management ofBRAFV600-mutant melanoma, there is still a compelling need for more effective treatments for patients who developedBRAF/NRASwild type disease. Since the activity of single targeted agents is limited by innate and acquired resistance, we performed a high-throughput drug screen using 180 drug combinations to generate over 18,000 viability curves, with the aim of identifying agents that synergise to killBRAF/NRASwild type melanoma cells. From this screen we observed strong synergy between the tyrosine kinase inhibitor nilotinib and MEK inhibitors and validated this combination in an independent cell line collection. We found that AXL expression was associated with synergy to the nilotinib/MEK inhibitor combination, and that both drugs work in concert to suppress pERK. This finding was supported by genome-wide CRISPR screening which revealed that resistance mechanisms converge on regulators of the MAPK pathway. Finally, we validated the synergy of nilotinib/trametinib combinationin vivousing patient-derived xenografts. Our results indicate that a nilotinib/MEK inhibitor combination may represent an effective therapy inBRAF/NRASwild type melanoma patients.

scholarly journals LZTR1 is a regulator of RAS ubiquitination and signaling

Science ◽  
2018 ◽  
Vol 362 (6419) ◽  
pp. 1171-1177 ◽  
Author(s):  
Johannes W. Bigenzahn ◽  
Giovanna M. Collu ◽  
Felix Kartnig ◽  
Melanie Pieraks ◽  
Gregory I. Vladimer ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Kinase Inhibitors ◽  
Mapk Pathway ◽  
Resistance Mechanisms ◽  
Mitogen Activated Protein Kinase ◽  
Loss Of Function ◽  
Pathway Activation ◽  
Mitogen Activated Protein ◽  
Human Disorders ◽  
Ras Isoforms

In genetic screens aimed at understanding drug resistance mechanisms in chronic myeloid leukemia cells, inactivation of the cullin 3 adapter protein-encoding leucine zipper-like transcription regulator 1 (LZTR1) gene led to enhanced mitogen-activated protein kinase (MAPK) pathway activity and reduced sensitivity to tyrosine kinase inhibitors. Knockdown of theDrosophila LZTR1orthologCG3711resulted in a Ras-dependent gain-of-function phenotype. Endogenous human LZTR1 associates with the main RAS isoforms. Inactivation ofLZTR1led to decreased ubiquitination and enhanced plasma membrane localization of endogenous KRAS (V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog). We propose that LZTR1 acts as a conserved regulator of RAS ubiquitination and MAPK pathway activation. BecauseLZTR1disease mutations failed to revert loss-of-function phenotypes, our findings provide a molecular rationale forLZTR1involvement in a variety of inherited and acquired human disorders.

scholarly journals BRAF Inhibitors: Molecular Targeting and Immunomodulatory Actions

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1823 ◽  
Author(s):  
Ilaria Proietti ◽  
Nevena Skroza ◽  
Simone Michelini ◽  
Alessandra Mambrin ◽  
Veronica Balduzzi ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Checkpoint Inhibitors ◽  
Mapk Pathway ◽  
Tumour Microenvironment ◽  
Mitogen Activated Protein Kinase ◽  
Braf Inhibitors ◽  
Immunomodulatory Effects ◽  
Cytokine Levels ◽  
Braf Mutant

The BRAF inhibitors vemurafenib, dabrafenib and encorafenib are used in the treatment of patients with BRAF-mutant melanoma. They selectively target BRAF kinase and thus interfere with the mitogen-activated protein kinase (MAPK) signalling pathway that regulates the proliferation and survival of melanoma cells. In addition to their molecularly targeted activity, BRAF inhibitors have immunomodulatory effects. The MAPK pathway is involved in T-cell receptor signalling, and interference in the pathway by BRAF inhibitors has beneficial effects on the tumour microenvironment and anti-tumour immune response in BRAF-mutant melanoma, including increased immune-stimulatory cytokine levels, decreased immunosuppressive cytokine levels, enhanced melanoma differentiation antigen expression and presentation of tumour antigens by HLA 1, and increased intra-tumoral T-cell infiltration and activity. These effects promote recognition of the tumour by the immune system and enhance anti-tumour T-cell responses. Combining BRAF inhibitors with MEK inhibitors provides more complete blockade of the MAPK pathway. The immunomodulatory effects of BRAF inhibition alone or in combination with MEK inhibition provide a rationale for combining these targeted therapies with immune checkpoint inhibitors. Available data support the synergy between these treatment approaches, indicating such combinations provide an additional beneficial effect on the tumour microenvironment and immune response in BRAF-mutant melanoma.

scholarly journals The BRAF–MAPK signaling pathway is essential for cancer-immune evasion in human melanoma cells

2006 ◽  
Vol 203 (7) ◽  
pp. 1651-1656 ◽  
Author(s):  
Hidetoshi Sumimoto ◽  
Fumie Imabayashi ◽  
Tomoko Iwata ◽  
Yutaka Kawakami
Keyword(s):  
Immune Evasion ◽  
Cellular Proliferation ◽  
Mapk Pathway ◽  
Synergistic Effects ◽  
Mek Inhibitor ◽  
Melanoma Cells ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Factor Α

The mitogen-activated protein kinase (MAPK) pathway is frequently activated in human cancers, leading to malignant phenotypes such as autonomous cellular proliferation. Here, we demonstrate a novel role of the activated MAPK pathway in immune evasion by melanoma cells with the mutation of BRAF, which encodes a MAPKKs, (BRAFV600E). MEK inhibitor U0126 or RNA interference (RNAi) for BRAFV600E decreased production of the immunosuppressive soluble factors interleukin (IL)-10, VEGF, or IL-6 from melanoma cells to levels comparable to those after signal transducer and activator of transcription (STAT)3 inactivation. The suppressive activity of the culture supernatants from the melanoma cells on the production of inflammatory cytokines IL-12 and tumor necrosis factor α by dendritic cells upon lipopolysaccharide stimulation was markedly reduced after transduction with BRAFV600E RNAi, comparable to the effects observed with STAT3 RNAi transduction. No additive or synergistic effects were observed by the simultaneous transduction of RNAi for both BRAFV600E and STAT3. Furthermore, specific DNA binding and transcriptional activity of STAT3 were not affected by down-regulation of the MAPK signaling with the BRAF RNAi. These results indicate that the MAPK signal, along with the STAT3 signal, is essential for immune evasion by human melanomas that have constitutively active MAPK signaling and is a potential molecular target for overcoming melanoma cell evasion of the immune system.

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