scholarly journals HSP70 Inhibition Blocks Adaptive Resistance and Synergizes with MEK Inhibition for the Treatment of NRAS-Mutant Melanoma

2021 ◽  
Vol 1 (1) ◽  
pp. 1-13
Author(s):  
Joshua L.D. Parris ◽  
Thibaut Barnoud ◽  
Julia I.-Ju Leu ◽  
Jessica C. Leung ◽  
Weili Ma ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Acquired Resistance ◽  
Insoluble Fraction ◽  
Tumor Type ◽  
Mek Inhibitors ◽  
Mek Inhibition ◽  
Adaptive Resistance ◽  
The Impact ◽  
Hsp70 Inhibitors ◽  
The Brain

NRAS-mutant melanoma is currently a challenge to treat. This is due to an absence of inhibitors directed against mutant NRAS, along with adaptive and acquired resistance of this tumor type to inhibitors in the MAPK pathway. Inhibitors to MEK have shown some promise for NRAS-mutant melanoma. In this work, we explored the use of MEK inhibitors for NRAS-mutant melanoma. At the same time, we investigated the impact of the brain microenvironment, specifically astrocytes, on the response of a melanoma brain metastatic cell line to MEK inhibition. These parallel avenues led to the surprising finding that astrocytes enhance the sensitivity of melanoma tumors to MEK inhibitors (MEKi). We show that MEKi cause an upregulation of the transcriptional regulator ID3, which confers resistance. This upregulation of ID3 is blocked by conditioned media from astrocytes. We show that silencing ID3 enhances the sensitivity of melanoma to MEKi, thus mimicking the effect of the brain microenvironment. Moreover, we report that ID3 is a client protein of the chaperone HSP70, and that HSP70 inhibition causes ID3 to misfold and accumulate in a detergent-insoluble fraction in cells. We show that HSP70 inhibitors synergize with MEKi against NRAS-mutant melanoma, and that this combination significantly enhances the survival of mice in two different models of NRAS-mutant melanoma. These studies highlight ID3 as a mediator of adaptive resistance, and support the combined use of MEK and HSP70 inhibitors for the therapy of NRAS-mutant melanoma. Significance: MEKi are currently used for NRAS-mutant melanoma, but have shown modest efficacy as single agents. This research shows a synergistic effect of combining HSP70 inhibitors with MEKi for the treatment of NRAS mutant melanoma.

scholarly journals Combined BRAF and MEK Inhibition with Vemurafenib and Cobimetinib for Patients with Advanced Melanoma

2017 ◽  
Vol 13 (01) ◽  
pp. 1
Author(s):  
Antonio M Grimaldi ◽  
Ester Simeone ◽  
Lucia Festino ◽  
Vito Vanella ◽  
Paolo A Ascierto ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Combined Therapy ◽  
Acquired Resistance ◽  
Braf Inhibitor ◽  
Progression Free Survival ◽  
Standard Of Care ◽  
Phase Iii ◽  
Free Survival ◽  
Mek Inhibition ◽  
Braf Mutant

Acquired resistance is the most common cause of BRAF inhibitor monotherapy treatment failure, with the majority of patients experiencing disease progression with a median progression-free survival of 6-8 months. As such, there has been considerable focus on combined therapy with dual BRAF and MEK inhibition as a means to improve outcomes compared with monotherapy. In the COMBI-d and COMBI-v trials, combined dabrafenib and trametinib was associated with significant improvements in outcomes compared with dabrafenib or vemurafenib monotherapy, in patients with BRAF-mutant metastatic melanoma. The combination of vemurafenib and cobimetinib has also been investigated. In the phase III CoBRIM study in patients with unresectable stage III-IV BRAF-mutant melanoma, treatment with vemurafenib and cobimetinib resulted in significantly longer progression-free survival and overall survival (OS) compared with vemurafenib alone. One-year OS was 74.5% in the vemurafenib and cobimetinib group and 63.8% in the vemurafenib group, while 2-year OS rates were 48.3% and 38.0%, respectively. The combination was also well tolerated, with a lower incidence of cutaneous squamous-cell carcinoma and keratoacanthoma compared with monotherapy. Dual inhibition of both MEK and BRAF appears to provide a more potent and durable anti-tumour effect than BRAF monotherapy, helping to prevent acquired resistance as well as decreasing adverse events related to BRAF inhibitor-induced activation of the MAPK-pathway. Combined BRAF and MEK inhibition is the standard of care in patients with advanced BRAF-mutant melanoma.

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.

Whole exome and whole transcriptome sequencing in melanoma patients to identify mechanisms of resistance to combined RAF/MEK inhibition.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 9015-9015 ◽  
Author(s):  
Nikhil Wagle ◽  
Eliezer Mendel Van Allen ◽  
Dennie T. Frederick ◽  
Zachary A. Cooper ◽  
Deborah Norman Farlow ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Acquired Resistance ◽  
Intrinsic Resistance ◽  
Mek Inhibition ◽  
Whole Exome ◽  
Rnaseq Data ◽  
Whole Transcriptome Sequencing ◽  
Alternatively Spliced ◽  
Pre Treatment ◽  
Braf Mutant

9015 Background: The RAF inhibitors vemurafenib and dabrafenib (D) and the MEK inhibitor trametinib (T) improve survival as monotherapies in BRAF-mutant melanoma. Since clinical mechanisms of resistance (MoR) result in MAPK pathway reactivation, recent efforts have focused on combined targeting of RAF and MEK. The combination of D and T (D/T) increased progression-free survival and response rate compared with D alone (Flaherty et al, NEJM, 2012). The MoR to this combination remain unknown. Methods: To look for clinical MoR to combined RAF/MEK inhibition, we performed whole exome (WES) and whole transcriptome sequencing (RNASeq) on tumors from 4 patients (pts) with acquired resistance and 1 pt with intrinsic resistance to D/T. Pre-treatment and post-resistance tumors from all pts were analyzed for point mutations, insertions/deletions, copy number alterations, alternatively spliced transcripts, rearrangements, and expression changes. Results: In 2 of 4 pts with acquired resistance, WES identified mutations in MEK1 and MEK2 that were undetectable in the pre-treatment tumors. In the 3rd pt, RNASeq identified an alternatively spliced isoform of BRAF lacking exons 2-10, also undetectable in the pre-treatment tumor. In the 4th pt, no obvious MoR were seen, though multiple alterations were enriched in the post-resistance tumor. The pt with intrinsic resistance had several alterations in genes that conferred resistance to RAF/MEK inhibition when overexpressed in BRAF-mutant cell lines. Integration of WES and RNASeq data also identified several co-existing alterations that may synergize to increase resistance. Conclusions: Analysis of combined WES and RNASeq data from pt samples provides a more complete picture of clinical MoR to MAPK-targeted therapy. Post-resistance tumors from 3 of 4 pts with acquired resistance to D/T had alterations in MAPK genes not detectable in the pre-treatment tumors, suggesting that resistance involves reactivation of the MAPK pathway despite combined RAF/MEK inhibition. Alternative dosing of current agents, more potent RAF/MEK inhibitors, and/or inhibition of the downstream kinase ERK may be needed for durable control of BRAF-mutant melanoma.

Role of MEK inhibition in improving anti-tumor responses in xenograft models of BRAF-mutated metastatic colorectal cancer.

2016 ◽  
Vol 34 (4_suppl) ◽  
pp. 265-265 ◽  
Author(s):  
Van Karlyle Morris ◽  
Ji Wu ◽  
Liana Adam ◽  
Feng Tian ◽  
Mihai Gagea ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Metastatic Colorectal Cancer ◽  
Tumor Regression ◽  
Mapk Pathway ◽  
Acquired Resistance ◽  
Mapk Signaling ◽  
Kras Mutations ◽  
Mek Inhibition ◽  
Egfr Inhibition ◽  
Pdx Models

265 Background: BRAFV600E mutations occur in fewer than 10% of all patients with metastatic colorectal cancer (mCRC) and are associated with poor survival outcomes. Addition of anti-EGFR therapy improves responses when combined with BRAF inhibition, yet acquired resistance to targeted therapies invariably develops. Novel therapeutic approaches to deepen anti-tumor activity are warranted for patients with this subset of mCRC. Methods: Patient-derived xenograft (PDX) models of BRAFV600E mCRC were established and treated with vemurafenib (V) +/- cetuximab (C) until acquired resistance. DNA from resistant tumors was sequenced and compared to that of untreated controls. BRAFV600E mCRC tumors from PDX mice with acquired mutations in MAPK signaling were reimplanted into another generation of nude mice and treated with V +C or trametinib (T) + cetuximab. Results: Twelve resistant models were developed in BRAFV600E mCRC PDX models treated with V +/- C, with nine models demonstrating acquired mutations resulting in MAPK pathway re-activation, including codons 12 or 13 KRAS mutations. While sensitivity to V + C was observed in BRAFV600E /KRASwild-type mCRC tumors, this combination demonstrated no anti-tumor response in BRAFV600E models with acquired KRASG12R or KRASG12D mutations. In these PDX models harboring dual BRAF/KRAS mutations, the combination of T + C generated sustained tumor regression not observed with V+C (P <.001 for both BRAFV600E / KRASG12R and BRAFV600E /KRASG12D models). Addition of T following resistance to V+C restored sensitivity in both models. Conclusions: Dual blockade of BRAF + EGFR has shown promise in early-phase clinical trials for patients with BRAFV600E mCRC, and MAPK pathway reactivation appears to be a critical mechanism of resistance. These results suggest that use of a MEK inhibition may reverse such acquired resistance. While MEK + EGFR targeting has been associated with excessive skin toxicity in humans, these data provide rationale for the pursuit of triple BRAF + MEK + EGFR inhibition in patients with BRAFV600E mCRC.

scholarly journals QOL-36. USE OF CANNABINOIDS IN THE PEDIATRIC CENTRAL NERVOUS SYSTEM TUMOR POPULATION

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii438-iii438
Author(s):  
Kathleen Dorris ◽  
Jessica Channell ◽  
Ashley Mettetal ◽  
Molly Hemenway ◽  
Natalie Briones ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Central Nervous System ◽  
Nervous System ◽  
Cell Activity ◽  
Cns Tumors ◽  
Low Grade ◽  
Tumor Type ◽  
Central Nervous System Tumor ◽  
The Impact

Abstract BACKGROUND Cannabinoids, including cannabidiol (CBD) and tetrahydrocannabinol (THC), are a class of compounds found in marijuana. Numerous studies in adults have examined cannabinoid use in management of cancer-related symptoms such as nausea, anorexia, and pain. Less is known about the use in the pediatric oncology population. METHODS A prospective observational study has been ongoing since 2016 at Children’s Hospital Colorado to evaluate cannabinoids’ impact using PedsQL™ modules on quality of life of pediatric patients with central nervous system (CNS) tumors who are 2–18 years old. Laboratory assessments of T-cell activity and pharmacokinetics of CBD, THC and associated metabolites are in process. Diaries with exploratory information on cannabinoid use patterns are being collected. RESULTS Thirty-three patients (14:19; male:female) have been enrolled with a median age of 6.4 years (range, 2.9–17.7 years). The most common tumor type in enrolled patients is embryonal tumors (13/33; 39%). Nine (27%) patients have low-grade glial/glioneuronal tumors, and eight (24%) had high-grade/diffuse midline gliomas. The remaining patients had ependymoma or craniopharyngioma. The median time on cannabinoids is 9 months. Most (n=20) patients have used oral products with CBD and THC. One patient continues on cannabinoid therapy in follow up. Preliminary immune function analyses identified impaired neutrophil superoxide anion production and chemotaxis in patients taking cannabinoids at early time points on therapy. CONCLUSIONS Families of children with various CNS tumors are pursuing cannabinoid therapy for both antitumor and supportive care purposes. Analysis of the impact of cannabinoids on patients’ quality of life is ongoing.

scholarly journals Monosomy 3 Is Linked to Resistance to MEK Inhibitors in Uveal Melanoma

2021 ◽  
Vol 22 (13) ◽  
pp. 6727
Author(s):  
Svenja Mergener ◽  
Jens T. Siveke ◽  
Samuel Peña-Llopis
Keyword(s):  
Cell Lines ◽  
Uveal Melanoma ◽  
Survival Data ◽  
Translation Initiation Factor ◽  
The Cancer Genome Atlas ◽  
Initiation Factor ◽  
Chromosome 3 ◽  
Mek Inhibitors ◽  
Mek Inhibition ◽  
Insight Into

The use of MEK inhibitors in the therapy of uveal melanoma (UM) has been investigated widely but has failed to show benefits in clinical trials due to fast acquisition of resistance. In this study, we investigated a variety of therapeutic compounds in primary-derived uveal melanoma cell lines and found monosomy of chromosome 3 (M3) and mutations in BAP1 to be associated with higher resistance to MEK inhibition. However, reconstitution of BAP1 in a BAP1-deficient UM cell line was unable to restore sensitivity to MEK inhibition. We then compared UM tumors from The Cancer Genome Atlas (TCGA) with mutations in BAP1 with tumors with wild-type BAP1. Principal component analysis (PCA) clearly differentiated both groups of tumors, which displayed disparate overall and progression-free survival data. Further analysis provided insight into differential expression of genes involved in signaling pathways, suggesting that the downregulation of the eukaryotic translation initiation factor 2A (EIF2A) observed in UM tumors with BAP1 mutations and M3 UM cell lines might lead to a decrease in ribosome biogenesis while inducing an adaptive response to stress. Taken together, our study links loss of chromosome 3 with decreased sensitivity to MEK inhibition and gives insight into possible related mechanisms, whose understanding is fundamental to overcome resistance in this aggressive tumor.

scholarly journals Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 892
Author(s):  
Elisa L. J. Moya ◽  
Elodie Vandenhaute ◽  
Eleonora Rizzi ◽  
Marie-Christine Boucau ◽  
Johan Hachani ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Blood Brain Barrier ◽  
Early Stage ◽  
Molecular Transport ◽  
Brain Barrier ◽  
Blood Brain ◽  
Cns Drugs ◽  
The Impact ◽  
The Brain

Central nervous system (CNS) diseases are one of the top causes of death worldwide. As there is a difficulty of drug penetration into the brain due to the blood–brain barrier (BBB), many CNS drugs treatments fail in clinical trials. Hence, there is a need to develop effective CNS drugs following strategies for delivery to the brain by better selecting them as early as possible during the drug discovery process. The use of in vitro BBB models has proved useful to evaluate the impact of drugs/compounds toxicity, BBB permeation rates and molecular transport mechanisms within the brain cells in academic research and early-stage drug discovery. However, these studies that require biological material (animal brain or human cells) are time-consuming and involve costly amounts of materials and plastic wastes due to the format of the models. Hence, to adapt to the high yields needed in early-stage drug discoveries for compound screenings, a patented well-established human in vitro BBB model was miniaturized and automated into a 96-well format. This replicate met all the BBB model reliability criteria to get predictive results, allowing a significant reduction in biological materials, waste and a higher screening capacity for being extensively used during early-stage drug discovery studies.

scholarly journals The Impact of Bone on the Biology of Aging

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 740-740
Author(s):  
Gerard Karsenty
Keyword(s):  
Muscle Function ◽  
Male Fertility ◽  
Leydig Cells ◽  
Memory Loss ◽  
Age Related ◽  
Systematic Exploration ◽  
Biology Of Aging ◽  
The Impact ◽  
The Brain ◽  
Regulate Energy Metabolism

Abstract We hypothesized that bone may secrete hormones that regulate energy metabolism and reproduction. Testing this hypothesis revealed that the osteoblast-specific secreted protein osteocalcin is a hormone regulating glucose homeostasis and male fertility by signaling through a GPCR, Gprc6a, expressed in pancreatic β bells and Leydig cells of the testes. The systematic exploration of osteocalcin biology, revealed that it regulates an unexpectedly large spectrum of physiological functions in the brain and peripheral organs and that it has most features of an antigeromic molecule. As will be presented at the meeting, this body of work suggests that harnessing osteocalcin for therapeutic purposes may be beneficial in the treatment of age-related diseases such as depression, age-related memory loss and the decline in muscle function seen in sarcopenia.

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