scholarly journals Combating acquired resistance to MAPK inhibitors in melanoma by targeting Abl1/2-mediated reactivation of MEK/ERK/MYC signaling

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Rakshamani Tripathi ◽  
Zulong Liu ◽  
Aditi Jain ◽  
Anastasia Lyon ◽  
Christina Meeks ◽  
...  
Keyword(s):  
Acquired Resistance ◽  
Mek Inhibitor ◽  
Mek Inhibitors ◽  
Incurable Disease ◽  
Limited Success ◽  
Metastatic Burden ◽  
Mapk Inhibitors ◽  
Inhibitor Resistance ◽  
Braf Mutant

Abstract Metastatic melanoma remains an incurable disease for many patients due to the limited success of targeted and immunotherapies. BRAF and MEK inhibitors reduce metastatic burden for patients with melanomas harboring BRAF mutations; however, most eventually relapse due to acquired resistance. Here, we demonstrate that ABL1/2 kinase activities and/or expression are potentiated in cell lines and patient samples following resistance, and ABL1/2 drive BRAF and BRAF/MEK inhibitor resistance by inducing reactivation of MEK/ERK/MYC signaling. Silencing/inhibiting ABL1/2 blocks pathway reactivation, and resensitizes resistant cells to BRAF/MEK inhibitors, whereas expression of constitutively active ABL1/2 is sufficient to promote resistance. Significantly, nilotinib (2nd generation ABL1/2 inhibitor) reverses resistance, in vivo, causing prolonged regression of resistant tumors, and also, prevents BRAFi/MEKi resistance from developing in the first place. These data indicate that repurposing the FDA-approved leukemia drug, nilotinib, may be effective for prolonging survival for patients harboring BRAF-mutant melanomas.

scholarly journals IGF1R/IR Mediates Resistance to BRAF and MEK Inhibitors in BRAF-Mutant Melanoma

Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5863
Author(s):  
Hima Patel ◽  
Rosalin Mishra ◽  
Nour Yacoub ◽  
Samar Alanazi ◽  
Mary Kate Kilroy ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Lines ◽  
Treatment Options ◽  
Acquired Resistance ◽  
Resistant Cell ◽  
Sequencing Analysis ◽  
Mek Inhibitors ◽  
Braf Mutant

The use of BRAF and MEK inhibitors for patients with BRAF-mutant melanoma is limited as patients relapse on treatment as quickly as 6 months due to acquired resistance. We generated trametinib and dabrafenib resistant melanoma (TDR) cell lines to the MEK and BRAF inhibitors, respectively. TDR cells exhibited increased viability and maintenance of downstream p-ERK and p-Akt as compared to parental cells. Receptor tyrosine kinase arrays revealed an increase in p-IGF1R and p-IR in the drug resistant cells versus drug sensitive cells. RNA-sequencing analysis identified IGF1R and INSR upregulated in resistant cell lines compared to parental cells. Analysis of TCGA PanCancer Atlas (skin cutaneous melanoma) showed that patients with a BRAF mutation and high levels of IGF1R and INSR had a worse overall survival. BMS-754807, an IGF1R/IR inhibitor, suppressed cell proliferation along with inhibition of intracellular p-Akt in TDR cells. Dual inhibition of IGF1R and INSR using siRNA reduced cell proliferation. The combination of dabrafenib, trametinib, and BMS-754807 treatment reduced in vivo xenograft tumor growth. Examining the role of IGF1R and IR in mediating resistance to BRAF and MEK inhibitors will expand possible treatment options to aid in long-term success for BRAF-mutant melanoma patients.

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 BRAF Mutant Melanoma Adjusts to BRAF/MEK Inhibitors via Dependence on Increased Antioxidant SOD2 and Increased Reactive Oxygen Species Levels

Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1661 ◽  
Author(s):  
Long Yuan ◽  
Rosalin Mishra ◽  
Hima Patel ◽  
Samar Alanazi ◽  
Xin Wei ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Braf Inhibitor ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Braf Mutations ◽  
Mek Inhibitors ◽  
Braf Mutant ◽  
Resistant Cells

B-Rapidly Accelerated Fibrosarcoma (BRAF) mutations are found in about 50% of melanoma patients. Treatment with Food and Drug Administration (FDA)-approved BRAF and MAP/ERK kinase (MEK) inhibitors has improved progression free and overall survival of patients with BRAF mutant melanoma. However, all responders develop resistance typically within 1 year of treatment with these inhibitors. Evidence indicates that reactive oxygen species (ROS) levels are elevated after BRAF pathway inhibition treatment. We aim to decipher the role of mitochondrial antioxidant proteins relative to ROS levels and BRAF pathway inhibitor resistance. We observed BRAF mutant melanoma cells treated with the combination of a MEK inhibitor (trametinib) and a BRAF inhibitor (dabrafenib), exhibited elevated ROS levels, both in in vitro and in vivo melanoma models. We next generated trametinib- and dabrafenib-resistant (TDR) cells and found increased ROS levels after acquisition of resistance. An immunofluorescence experiment showed an increase of DNA damage in TDR cell lines. Furthermore, we observed that TDR cells increased superoxide dismutase 2 (SOD2), an antioxidant, at both mRNA and protein levels, with the upregulation of the transcription factor Nuclear Factor (NF)-κB. Knockdown of SOD2 significantly reduced the growth of BRAF pathway inhibitor-resistant cells. In addition, the results indicate that TDR cells can be re-sensitized to BRAF pathway inhibitors by the ROS scavenger, N-Acetyl Cysteine (NAC). Overall, these data indicate that BRAF pathway inhibitor-resistant cells can compensate for elevated ROS via increased expression of the antioxidant SOD2.

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 DDIS-32. MEK INHIBITORS INDUCES NEURONAL DIFFERENTIATION IN EGFR AMPLIFIED GLIOMA STEM LIKE CELLS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi70-vi70
Author(s):  
Veerakumar Balasubramaniyan ◽  
Soon Park ◽  
Yuji Piao ◽  
Emmanuel Martínez ◽  
Jianwen Dong ◽  
...  
Keyword(s):  
Neuronal Differentiation ◽  
High Throughput ◽  
Target Genes ◽  
Acquired Resistance ◽  
Mek Inhibitor ◽  
Therapeutic Benefit ◽  
Mitogen Activated Protein Kinase ◽  
Sequencing Analysis ◽  
Mek Inhibitors ◽  
Mek Inhibition

Abstract The median survival for patients with glioblastoma (GBM) is 12–15 months highlighting the need for better therapeutic strategies for this deadly disease. Genomic and epigenomic sequencing analysis at the single cell level have identified multiple genomic aberrations as potential targets for therapeutic intervention in GBM. EGFR and PDGFR amplification are evident in nearly 40% and 12% of human GBM, respectively. Although the first and second-generation EGFR tyrosine kinase small molecule inhibitors failed to show long term therapeutic benefit in GBM patients, multiple factors such as incorrect patient selection, acquired resistance, and drug-target heterogeneity may all lead to clinical failure of targeted therapies. Although the multilevel genomic characterization of gliomas are increasing, the clinical translation of these findings is beginning to unravel. In this study, we attempted to correlate the genomic variations using an unbiased high throughput drug screen using primary glioma stem-like cell (GSCs) as our model system. An unbiased high-throughput screen utilizing our GSC models identified that glioblastoma cells harboring focal EGFR amplification are sensitive to mitogen-activated protein kinase (MEK) inhibitors. MEK inhibition induced apoptosis in EGFR amplified cells at low concentration. RNA sequence analysis of cells treated with MEK inhibitors revealed upregulation of genes related to neuronal differentiation and down regulation of MEK target genes in MEK sensitive glioma stem cells. Additionally, RNA sequencing of GSCs with acquired MEK inhibitor resistance demonstrated an upregulation of oncogenic transcription factor ETS Variant Gene 1 (ETV1) as a mediator of resistance. Overall our data suggest that the MEK inhibition in combination with ETV inhibitors could be a potential therapeutic target for a subset of GBM patients.

Effect of bypass kinase pathways on acquired CDK4/6 inhibitor resistance.

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 379-379
Author(s):  
Renee De Leeuw ◽  
Christopher McNair ◽  
Matthew Joseph Schiewer ◽  
Neermala Poudel Neupane ◽  
Michael Augello ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Early Stage ◽  
Mapk Signaling ◽  
Cross Resistance ◽  
Mek Inhibitors ◽  
Mesenchymal Transition ◽  
Inhibitor Resistance ◽  
Tumor Types

379 Background: Cyclin Dependent Kinase-4/6 (CDK4/6) kinase inhibitors have shown clinical benefit in treatment of solid tumor types, including breast cancer. However, resistance is common, and the underpinning mechanisms of action are not well understood. Given the dependence of CDK4/6 inhibitors on retinoblastoma tumor suppressor (RB) function for activity, this class of agents may be particularly effective in tumor types for which RB loss is infrequent or occurs late in tumor progression. Methods: Here, models of acquired palbociclib resistance were generated in early stage, RB positive cancers, wherein it was shown acquired palbociclib resistance resulted in cross-resistance to other CDK4/6 inhibitors under clinical testing. Results: Cells showing acquired resistance exhibited aggressive in vitro and in vivo phenotypes without genetic loss of RB or RB pathway members, including enhanced proliferative capacity, migratory potential, and characteristics of epithelial to mesenchymal transition. Further analyses through integration of RNA sequencing and phospho-proteomics identified activation of the MAPK signaling pathway as a mediator of CDK4/6 inhibitor resistance, capable of bypassing CDK4/6 activity. However, this altered kinase dependence resulted in sensitization to MEK inhibitors, suggestive of new clinical opportunities in CDK4/6 resistant tumors. Conclusions: In sum, the studies herein not only identify activation of the MAPK pathway as capable of bypassing the CDK4/6 requirement and promoting aggressive tumor characteristics, but nominate MEK inhibitors as potential mechanisms to treat or prevent CDK4/6 inhibitor resistance.

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 Overactivation of Akt Contributes to MEK Inhibitor Primary and Acquired Resistance in Colorectal Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1866 ◽  
Author(s):  
Tsubaki ◽  
Takeda ◽  
Noguchi ◽  
Jinushi ◽  
Seki ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Cells ◽  
Critical Role ◽  
Pik3ca Mutation ◽  
Acquired Resistance ◽  
Mek Inhibitor ◽  
Blue Dye ◽  
Colorectal Cancer Cells ◽  
Inhibitor Resistance ◽  
Ht 29

RAS and BRAF-mutated colorectal cancers are associated with resistance to chemotherapy and poor prognosis, highlighting the need for new therapeutic strategies. Although these cancers sometimes respond to mitogen activated protein kinase kinase (MEK) inhibitor treatment, they often acquire resistance via mechanisms, which are poorly understood. Here, we investigated the mechanism of MEK inhibitor resistance in primary- and acquired-resistant cells. Cell viability was examined using the trypan blue dye exclusion assay. Protein expression was analyzed by western blotting. Somatic mutations in colorectal cancer cells were investigated using the polymerase chain reaction array. PD0325901 and trametinib induced cell death in LoVo and Colo-205 cells but not in DLD-1 and HT-29 cells, which have a PIK3CA mutation constitutively activating Akt and NF-κB. Treatment with PD0325901 and trametinib suppressed ERK1/2 activation in all four cell lines but only induced Akt and NF-κB activation in DLD-1 and HT-29 cells. Inhibition of Akt but not NF-κB, overcame MEK inhibitor resistance in DLD-1 and HT-29 cells. Acquired-resistant LoVo/PR, Colo-205/PR and LoVo/TR cells have constitutively active Akt due to a M1043V mutation in the kinase activation loop of PIK3CA and Akt inhibitor resensitized these cells to MEK inhibitor. These results demonstrate that the overactivation of Akt plays a critical role in MEK inhibitor primary and acquired resistance and implicate combined Akt/MEK inhibition as a potentially useful treatment for RAS/BRAF-mutated colorectal cancer.

scholarly journals DDRE-25. NOVEL TEMOZOLOMIDE ANALOGS TO IMPROVE ANTI-TUMOR EFFICACY AND OVERCOME RESISTANCE IN GLIOBLASTOMA MULTIFORME

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii66-ii67
Author(s):  
Ariana Waters ◽  
Nozomi Tomimatsu ◽  
Ivan Babic ◽  
Elmar Nurmemmedov ◽  
Annamarie Allnutt ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Acquired Resistance ◽  
Treatment Strategies ◽  
Standard Of Care ◽  
Over Expression ◽  
Methylguanine Dna Methyltransferase ◽  
Incurable Disease ◽  
Anticancer Effects ◽  
Anti Cancer

Abstract Glioblastoma (GBM) is considered one of the most lethal forms of human cancers, and despite considerable advances in multimodality treatments, it remains an incurable disease with an overall survival of 14 to 16 months after diagnosis. Even in the era of personalized medicine and immunotherapy, temozolomide (TMZ), an oral alkylating agent, remains the standard-of-care for GBM. However, intrinisic or acquired resistance to TMZ due to over expression of O6-methylguanine-DNA methyltransferase (MGMT) results in initial treatment inefficacy or tumor relapse, highlighting the significant need for improved treatment strategies. Recently, much effort has been directed towards creating novel TMZ analogs to address the clinical barriers associated with TMZ. While some reported TMZ analogs showed improved brain permeability and anticancer effects in preclinical models, none of them have progressed to testing in humans. There is therefore significant room to improve the brain permeability and anticancer effect profiles of TMZ by incorporating yet unexplored functional groups into new analogs. We have designed and synthesized a series of novel C8-substituted TMZ analogs and have evaluated their anticancer potency against a panel of GBM cell lines with variable levels of MGMT expression. Encouragingly, our analogs demonstrated promising anti-cancer effect in both MGMT low and high expressing lines. We then evaluated our analogs in a variety of cell based assays to compare their activity with TMZ, and performed in vivo brain permeability and anti-tumor efficacy assays in mouse flank models. Our results demonstrated that several of our analogs clearly display improved anti-cancer effects and increased brain permeability over TMZ. This work points to a new direction for the development of novel TMZ analogs for improved patient survival.

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