Project description:This is a Phase 1b/2, multi-center, open label umbrella study of patients ≥12 years of age with recurrent, progressive, or refractory melanoma or other solid tumors with alterations in the key proteins of the RAS/RAF/MEK/ERK pathway, referred to as the MAPK pathway.
Project description:Bis-2-chloroethyl sulfide (sulfur mustard, SM) is a potent alkylating agent and vesicant. Exposure to SM results in activation of numerous signaling cascades, including mitogen-activated protein kinase (MAPK) signaling pathways. These pathways include the Erk, p38, and JNK pathways, which are involved in cell growth, inflammation, and stress signaling. However, the precise roles of these pathways in SM toxicity have not been fully elucidated. We used Western blotting and microarray analysis to examine the activation and role of each pathway following SM exposure in primary human epidermal keratinocytes. Western blotting revealed increased phosphorylation of p38 and JNK following SM exposure; however, phosphorylation of Erk was equivocal, suggesting that growth conditions may impact activation of Erk by SM. We used pharmacologic inhibitors to target each MAPK and then compared the gene expression profiles to identify SM-induced gene networks regulated by each MAPK. Cells were pretreated with 10 µM SB 203580 (p38 inhibitor), PD 98059 (Erk inhibitor), or SP 600125 (JNK inhibitor) 60 minutes before exposure to 200 µM SM. Cells were harvested at 1h, 4h, and 8h post-exposure, and RNA was extracted for synthesis of microarray probes. Probes were hybridized to Affymetrix U133 Plus 2.0 arrays for gene expression profiling. Analysis of variance was performed to identify genes significantly modulated due to pharmacologic inhibition in SM-exposed cells. Pathway mapping confirmed alterations in SM-induced Erk, JNK, and p38 MAPK signaling due to pharmacologic inhibition. SM-induced expression of IL-8, IL-6, and TNF-alpha was decreased by p38 MAPK inhibition, but not by inhibition of other MAPKs. Based on the number of significant pathways mapped to each MAPK in the presence and absence of inhibitors, the p38 MAPK pathway appeared to be the MAPK pathway most responsive to SM exposure. Interestingly, pathway mapping of the microarray data identified potential cross-talk between MAPK signaling pathways and other pathways involved in SM-induced signaling. Mining of these results will increase our understanding of the role of MAPK pathways in SM-induced signal transduction and may identify potential therapeutic targets for medical countermeasure development.
Project description:KSR1 is a scaffolding protein for the RAS-RAF-MEK-ERK pathway, which is one of the most frequently altered pathways in human cancers. Previous results have shown that KSR1 has a critical role in mutant RAS mediated transformation. Here, we examined the role of KSR1 in mutant BRAF transformation. We used CRISPR/Cas9 to knock out KSR1 in a BRAFV600E transformed melanoma cell line. KSR1 loss produced a complex phenotype characterized by impaired proliferation, cell cycle defects, decreased transformation, decreased invasive migration, increased cellular senescence, and increased apoptosis. To decipher this phenotype, we used a combination of proteomic ERK substrate profiling, global protein expression profiling, and biochemical validation assays. The results suggest that KSR1 directs ERK to phosphorylate substrates that have a critical role in ensuring cell survival. The results furtherindicate that KSR1 loss induces the activation of p38 Mitogen-Activated Protein Kinase (MAPK) and subsequent cell cycle aberrations and senescence. In summary, KSR1 function plays a key role in oncogenic BRAF transformation.
Project description:KSR1 is a scaffolding protein for the RAS-RAF-MEK-ERK pathway, which is one of the most frequently altered pathways in human cancers. Previous results have shown that KSR1 has a critical role in mutant RAS mediated transformation. Here, we examined the role of KSR1 in mutant BRAF transformation. We used CRISPR/Cas9 to knock out KSR1 in a BRAFV600E transformed melanoma cell line. KSR1 loss produced a complex phenotype characterized by impaired proliferation, cell cycle defects, decreased transformation, decreased invasive migration, increased cellular senescence, and increased apoptosis. To decipher this phenotype, we used a combination of proteomic ERK substrate profiling, global protein expression profiling, and biochemical validation assays. The results suggest that KSR1 directs ERK to phosphorylate substrates that have a critical role in ensuring cell survival. The results further indicate that KSR1 loss induces the activation of p38 Mitogen- Activated Protein Kinase (MAPK) and subsequent cell cycle aberrations and senescence. In summary, KSR1 function plays a key role in oncogenic BRAF transformation.
Project description:Disruption of the MAPK pathway in cancer by kinase inhibition often fails due to pathway reactivation, causing clinical relapse. Among MAPK inhibitors, type I RAF inhibitors are only active against specific BRAF mutants; MEK inhibitor monotherapy is associated with limited clinical benefits but may serve as a foundation for combinatorial therapy. Here, we show that type II RAF plus allosteric MEK inhibitors durably blunt the development of acquired MEK inhibitor resistance among cancers with KRAS, NRAS, NF1, BRAFnon-V600 and BRAFV600 mutations, when compared to a combination of type II RAF plus ERK inhibitors. Type II RAF and MEK (versus ERK) inhibitors also display superior capacity to sequester MEK in RAF complexes and uncouple MEK and ERK interaction in acquired resistant tumor subpopulations. Systemically and intratumorally, type II RAF plus MEK inhibitors expand memory and activated/exhausted CD8+ T-cells. Whereas trametinib alone temporally reduces dominant intra-tumoral T-cell clones, type II RAF inhibitor co-treatment reverses this effect and promotes T-cell clonotypic expansion and convergence. Importantly, durably control of tumors by this combination requires CD8+ T-cells. Thus, the prolonged anti-tumor efficacy of type II RAF plus MEK inhibitors reveals exquisite MAPK addiction in common lethal cancer histologies, and the mechanisms include unexpected allosteric perturbation of the MAPK pathway and engagement of anti-tumor CD8+ T-cell immunity.
Project description:Disruption of the MAPK pathway in cancer by kinase inhibition often fails due to pathway reactivation, causing clinical relapse. Among MAPK inhibitors, type I RAF inhibitors are only active against specific BRAF mutants; MEK inhibitor monotherapy is associated with limited clinical benefits but may serve as a foundation for combinatorial therapy. Here, we show that type II RAF plus allosteric MEK inhibitors durably blunt the development of acquired MEK inhibitor resistance among cancers with KRAS, NRAS, NF1, BRAFnon-V600 and BRAFV600 mutations, when compared to a combination of type II RAF plus ERK inhibitors. Type II RAF and MEK (versus ERK) inhibitors also display superior capacity to sequester MEK in RAF complexes and uncouple MEK and ERK interaction in acquired resistant tumor subpopulations. Systemically and intratumorally, type II RAF plus MEK inhibitors expand memory and activated/exhausted CD8+ T-cells. Whereas trametinib alone temporally reduces dominant intra-tumoral T-cell clones, type II RAF inhibitor co-treatment reverses this effect and promotes T-cell clonotypic expansion and convergence. Importantly, durably control of tumors by this combination requires CD8+ T-cells. Thus, the prolonged anti-tumor efficacy of type II RAF plus MEK inhibitors reveals exquisite MAPK addiction in common lethal cancer histologies, and the mechanisms include unexpected allosteric perturbation of the MAPK pathway and engagement of anti-tumor CD8+ T-cell immunity.
Project description:Disruption of the MAPK pathway in cancer by kinase inhibition often fails due to pathway reactivation, causing clinical relapse. Among MAPK inhibitors, type I RAF inhibitors are only active against specific BRAF mutants; MEK inhibitor monotherapy is associated with limited clinical benefits but may serve as a foundation for combinatorial therapy. Here, we show that type II RAF plus allosteric MEK inhibitors durably blunt the development of acquired MEK inhibitor resistance among cancers with KRAS, NRAS, NF1, BRAFnon-V600 and BRAFV600 mutations, when compared to a combination of type II RAF plus ERK inhibitors. Type II RAF and MEK (versus ERK) inhibitors also display superior capacity to sequester MEK in RAF complexes and uncouple MEK and ERK interaction in acquired resistant tumor subpopulations. Systemically and intratumorally, type II RAF plus MEK inhibitors expand memory and activated/exhausted CD8+ T-cells. Whereas trametinib alone temporally reduces dominant intra-tumoral T-cell clones, type II RAF inhibitor co-treatment reverses this effect and promotes T-cell clonotypic expansion and convergence. Importantly, durably control of tumors by this combination requires CD8+ T-cells. Thus, the prolonged anti-tumor efficacy of type II RAF plus MEK inhibitors reveals exquisite MAPK addiction in common lethal cancer histologies, and the mechanisms include unexpected allosteric perturbation of the MAPK pathway and engagement of anti-tumor CD8+ T-cell immunity.
Project description:The objective of this expanded access program is to provide ulixertinib (BVD-523) for compassionate use in advanced cancer patients with MAPK pathway-altered solid tumor(s), including but not limited to KRAS, NRAS, HRAS, BRAF, MEK, and ERK mutations who have incomplete response to or have exhausted available therapies.
Ulixertinib is available for treatment as monotherapy or in combination with other clinically tolerable agent(s), conditionally approved by the drug manufacturer.
Project description:BRAF inhibitors are highly effective therapies for patients with BRAF V600 mutated metastatic melanoma. Patients who receive BRAF inhibitors develop a variety of hyper-proliferative skin conditions, whose pathogenic basis is the paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in BRAF wild-type cells. Most of these hyper-proliferative skin changes improve when a MEK inhibitor is co-administered, as a MEK inhibitor blocks paradoxical MAPK activation. We tested whether we could take advantage of the mechanistic understanding of the skin hyper-proliferative side effects of BRAF inhibitors to accelerate skin wound healing by inducing paradoxical MAPK activation. Here we show that the BRAF inhibitor vemurafenib accelerates human keratinocyte proliferation and migration by increasing ERK phosphorylation and cell cycle progression. Topical treatment with vemurafenib in two wound-healing models in mice accelerated cutaneous wound healing and improved the tensile strength of healing wounds through paradoxical MAPK activation; addition of a MEK inhibitor reversed the benefit of vemurafenib-accelerated wound healing. The same dosing regimen of topical BRAF inhibitor did not increase the incidence of cutaneous squamous cell carcinomas in mice even after the application of a carcinogen. Therefore, topical BRAF inhibitors may have clinical applications in accelerating the healing of skin wounds. Full depth incisional wound mice tissues with/without Vemurafenib treatment were sent for RNAseq analysis on day 2, 6 and 14
Project description:The mammalian genome contains two ERK/MAP kinase kinase genes, Mek1 and Mek2, which encode dual-specificity kinases responsible for ERK/MAP kinase activation. To define the function of ERK/MAPK signaling pathway in lung development, we performed tissue-specific deletions of Mek1 function in a Mek2 null background. Inactivation of both Mek genes in mesenchyme resulted in several phenotypes including giant omphalocele, skeletal defects, pulmonary hypoplasia, abnormal trachea patterning, and death at birth. Microarray analysis with RNA extracted from lungs of E15.5 Dermo1+/Cre, Mek1+/flox;Mek2-/-;Dermo1+/Cre and Mek1flox/flox;Mek2-/-;Dermo1+/Cre embryos was performed to evaluate the molecular impact of the loss of all Mek alleles in mesenchyme on lung development. . Total RNA was isolated from lungs of E15.5 Dermo1+/Cre embryos (control), from E15.5 Mek1+/flox;Mek2- /-;Dermo1+/Cre embryos (experimental) and from E15.5 Mek1flox/flox;Mek2-/-;Dermo1+/Cre embryos (experimental). Four specimens were analyzed per genotype.