Project description:To elucidate the mechanism by which CXCR2 perturbation in melanocytes could alter initiation and growth of BrafV600E/Pten-/- melanoma, we examined the transcriptome of tumors arising in BrafV600E/Pten-/-/Cxcr2WT (n=7) and BRAFV600E/PTEN-/-/CXCR2-/- (n=8) mice.
Project description:To evaluate the effect of the dual CXCR1/CXCR2 inhibitor SX-682 on tumor growth, BrafV600E/PTEN-/- mice were fed with either SX-682 chow (0.756 g/kg of SX-682, Syntrix Pharmaceuticals, Inc) or control chow for RNA-seq analysis.
Project description:Gene expression profiling was performed to access the changes in gene expression in melanomas from Pdk1-inactivated Brafv600E::Pten-/- mice. The expression profiles of the BrafV600E::Pten-/-::Pdk1-/- were compared to the BrafV600E::Pten-/-::Pdk+/+ genotypes. The analysis has identified several important signaling pathways in Pdk1-dependent melanomagenesis. Melanoma tumors from the BrafV600E::Pten-/-::Pdk1+/+ and BrafV600E::Pten-/-::Pdk1-/- genotypes were harvested and mRNA from each group was pooled to enable four biologically replicates analysis.
Project description:Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss of function mutations occur in 40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. To compare the response of PTEN null to PTEN wild type cells in an isogenic background, CRISPR was used to knock out PTEN in the A375 melanoma cell line that harbors a BRAFV600E mutation. RNA sequencing and functional kinome analysis revealed the loss of PTEN led to an induction of FOXD3 and an increase in expression of the FOXD3 target gene, ERBB3/HER3. Inhibition of BRAFand MEK1/2 in PTEN null, BRAFV600E cells dramatically induced expression of ERBB3/HER3 relative to wild type cells. A synergy screen of epigenetic modifiers and kinase inhibitors in combination with inhibitors for mutant BRAF/MEK1/2 identified the pan ERBB/HER inhibitor, neratinib, as reversing the resistance observed in PTEN null, BRAFV600E cells. The findings indicate PTEN null BRAFV600E melanoma becomes dependent on ERBB/HER signaling when treated with clinically approved BRAF and MEK inhibitors. Future studies are warranted to test neratinib reversal of resistance in patient melanomas expressing ERBB3/HER3 in combination with its dimerization partner ERBB2/HER2.
Project description:Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss of function mutations occur in 40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. To compare the response of PTEN null to PTEN wild type cells in an isogenic background, CRISPR was used to knock out PTEN in the A375 melanoma cell line that harbors a BRAFV600E mutation. Kinome profiling was performed using the parental line and two PTEN KO clones (5 and 11), treated with DMSO, or treated with 100nM dabrafenib and 10nM trametinib for 1 day or for 7 days. PTEN KO cells showed dramatically increased binding of HER3 and AKT3 compared to wild type. The activation of the SOX10-FOXD3-HER3-AKT axis in PTEN KO cells could be targeted with the ERBB/HER inhibitor neratinib.
Project description:Gene expression profiling was performed to access the changes in gene expression in melanomas from Pdk1-inactivated Brafv600E::Pten-/- mice. The expression profiles of the BrafV600E::Pten-/-::Pdk1-/- were compared to the BrafV600E::Pten-/-::Pdk+/+ genotypes. The analysis has identified several important signaling pathways in Pdk1-dependent melanomagenesis.
Project description:Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss of function mutations occur in 40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. To compare the response of PTEN null to PTEN wild type cells in an isogenic background, CRISPR was used to knock out PTEN a melanoma cell line that harbors a BRAFV600E mutation. RNA sequencing and functional kinome analysis revealed the loss of PTEN led to an induction of FOXD3 and an increase in expression of the FOXD3 target gene, ERBB3/HER3. Inhibition of BRAF and MEK1/2 in PTEN null, BRAFV600Ecells dramatically induced expression of ERBB3/HER3 relative to wild type cells. A synergy screen of epigenetic modifiers and kinase inhibitors in combination with BRAFi/MEKi identified the pan ERBB/HER inhibitor, neratinib, as reversing the resistance observed in PTEN null, BRAFV600Ecells. The findings indicate that PTEN null BRAFV600E melanoma exhibits increased reliance on ERBB/HER signaling when treated with clinically approved BRAFi/MEKi combinations. Future studies are warranted to test neratinib reversal of resistance in patient melanomas expressing ERBB3/HER3 in combination with its dimerization partner ERBB2/HER2.
Project description:The A375, human BRAFV600E mutant melanoma, cell line (wildtype), two PTEN-null, BRAFV600E cell lines (KO5 and KO11), and PI3K overexpression cells (WT and PI3K H1047R mutant) were treated with small molecule inhibitors (dabrafenib, BRAF inhibitor; trametinib, MEK inhibitor alone and in combination for 0, 1 and 7 days
Project description:Tumor-associated macrophages (TAMs) represent a major component of the tumor microenvironment that supports tumorigenesis. Here we found that prostate tumors are strongly infiltrated by TAMs expressing the C-X-C chemokine receptor type 2 (CXCR2). Pharmacological blockade of the CXCR2 receptor by a selective antagonist promoted the re-education of TAMs towards a pro-inflammatory phenotype. Strikingly, CXCR2 knockout monocytes infused in Ptenpc-/-; Trp53pc-/- mice preferentially differentiatied in TNFα-releasing pro-inflammatory macrophages leading to senescence induction and tumor inhibition. Moreover, tumor cells harboring PTEN deletion were more sensitive to TNFα-induced senescence, when compared to PTEN WT tumors, due to increased levels of TNFR1. Our results identify TAMs as a target in prostate cancer therapy and describe a novel therapeutic strategy based on CXCR2 blockade to harness the anti-tumorigenic potential of macrophages against this disease.