Project description:KRAS mutations are the ost abundand driver mutations found in lung adenocarcinoma patients. Unfortunately, there are no clinical approved inhibitors available, to directly target mutant forms of KRAS. The aim of the study was to unravel the impact of upstream Egfr activation in signaling of mutated K-ras. We found that upregulation of G12D mutant Kras induced genes was significantly impaired when Egfr was knocked out. Our data suggests that signaling of mutant Kras depends on upstream activation. This finding may be exploited therapeutically by targeting EGFR in KRAS mutant patients.
Project description:We have examined the both miRNA and mRNA expression profiles in 155 lung adenocarcinoma samples with known EGFR mutation status (52 mutated and 103 wild-type cases). An integrative analysis was performed to identify the unique miRNA-mRNA regulatory network in EGFR-mutated lung adenocarcinoma.
Project description:We have examined the both miRNA and mRNA expression profiles in 155 lung adenocarcinoma samples with known EGFR mutation status (52 mutated and 103 wild-type cases). An integrative analysis was performed to identify the unique miRNA-mRNA regulatory network in EGFR-mutated lung adenocarcinoma.
Project description:RAS pathway mutations, which are present in 30% of patients with chronic myelomonocytic leukemia (CMML) at diagnosis, confer a high risk of resistance to and progression after hypomethylating agent (HMA) therapy, the current standard of care for the disease. Using single-cell, multi-omics technologies, we sought to dissect the biological mechanisms underlying the initiation and progression of RAS pathway–mutated CMML. We found that RAS pathway mutations induced the transcriptional reprogramming of hematopoietic stem and progenitor cells (HSPCs), which underwent proliferation and monocytic differentiation in response to cell-intrinsic and -extrinsic inflammatory signaling that also impaired immune cells’ functions. HSPCs expanded at disease progression and relied on the NF-KB pathway effector MCL1 to maintain their survival, which explains why patients with RAS pathway–mutated CMML do not benefit from BCL2 inhibitors such as venetoclax. Our study has implications for developing therapies to improve the survival of patients with RAS pathway–mutated CMML.
Project description:The receptor tyrosine kinase (RTK) EGFR is overexpressed and mutated in NSCLC. These mutations can be targeted by RTK inhibitors (TKIs), such as erlotinib. Chromatin-modifying agents offer a novel therapy approach by sensitizing tumor cells to TKIs. The NSCLC cell lines HCC827 (EGFR mutant, adenocarcinoma), A549 (EGFR wt, adenocarcinoma) and NCI-H460 (EGFR wt, large cell carcinoma) were analyzed by SNP6.0 array. Changes in proliferation were quantified by WST-1 assay, apoptosis by Annexin V/7-AAD flow cytometry and histone marks (acH3, H3K4me1,-2,-3) by immunoblotting. Expectedly, the EGFR wt cell lines A549 and NCI-H460 were insensitive to the growth-inhibiting effect of single-agent erlotinib (IC50 70-100µM), compared to HCC827 (IC50 <0.02μM). Treatment with panobinostat diminished growth to <50% in both EGFR wt and <30% in HCC827 cells. The combination of both drugs significantly reduced proliferation by ≥70% in A549, >95% in HCC827, but not further in NCI-H460. Panobinostat alone induced differentiation and expression of p21WAF1/CIP1 and p53 in all three cell lines, with almost no further increase when combined with erlotinib. In contrast, combination treatment additively decreased pERK, pAKT and pEGFR in A549, and synergistically induced acH3 in both adenocarcinoma lines. Surprisingly, we also saw an induction of H3K4 methylation marks in all three cell lines. In conclusion, panobinostat synergistically sensitized lung adenocarcinoma cells to the antiproliferative effects of erlotinib. Since single-agent erlotinib has only modest clinical effects in adenocarcinoma EGFR wt patients, combination therapy with an HDACi might offer a promising therapy approach to extend this activity. Copy-number analysis of three NSCLC cell lines HCC827, A549 and NCI-H460 (in unicates) was performed according to protocol by Affymetrix Genome-Wide Human SNP-Array 6.0.
Project description:EZH2 was inactivated by shRNA in the RAS-mutated HL-60 acute myeloid leukemia cell line. RNA-seq genome wide expression profiling was used to screen for genes deregulated by EZH2 inactivation within this setting.
Project description:Intratumoral heterogeneity in EGFR mutant NSCLC results in divergent resistance mechanisms in response to EGFR tyrosine kinase inhibition We used microarrays to investigate the gene expression underlying EGFR TKI resistance with a mesenchymal phenotype.
Project description:Background: The receptor tyrosine kinase (RTK) EGFR is overexpressed and mutated in NSCLC. These mutations can be targeted by RTK inhibitors (TKIs) such as erlotinib. Chromatin-modifying agents may offer a novel therapeutic approach by sensitizing tumor cells to TKIs. Methods: The NSCLC cell lines HCC827 (EGFR mutant, adenocarcinoma), A549 (EGFR wt, adenocarcinoma) andNCI-H460 (EGFR wt, large cell carcinoma) were analyzed by SNP6.0 array. Changes in proliferation after panobinostat (LBH-589, PS) and erlotinib treatment were quantified by WST-1 assay and apoptosis by Annexin V/7-AAD flow cytometry. Abundance of target proteins and histone marks (acH3, H3K4me1/2/3) was determined by immunoblotting. Results: As expected, the EGFR wt cell lines A549 and NCI-H460 were quite insensitive to the growth-inhibitory effect of single-agent erlotinib (IC50 70-100 μM), compared to HCC827 (IC50 < 0.02 μM). PS treatment diminished growth to <50 % in both EGFR wt cells, and <30 % in HCC827. The combination of both drugs reduced proliferation by >95 % in HCC827, ≥70 % in A549, but not further in NCI-H460. PS alone induced differentiation and expression of p21WAF1/CIP1 and p53 and decreased CHK1 in all three cell lines, with almost no further effect when combined with erlotinib. In contrast, combination treatment additively decreased pEGFR, pERK, pAKT in A549, and synergistically induced acH3 in both adenocarcinoma lines. Surprisingly, we saw an induction of H3K4 methylation marks after erlotinib treatment in HCC827 (and to a lesser extent in A549) that was even further enhanced by combination with PS. Conclusion: We were able to show that PS synergistically sensitized lung adenocarcinoma cells to the antiproliferative effects of erlotinib. Since single-agent erlotinib has only modest clinical effects in lung adenocarcinoma EGFR wt patients, its combination with an HDACi might offer a promising therapy approach.
Project description:Abstract: RAS-like (RAL) GTPases function in Wnt signalling-dependent intestinal stem cell proliferation and regeneration. Whether RAL proteins work as canonical RAS effectors in the intestine, and the mechanisms of how they contribute to tumorigenesis remain unclear. Here, we show that RAL GTPases are necessary and sufficient to activate EGFR/MAPK signalling in the intestine. We identify non-canonical roles of RAL GTPases not as RAS effectors, but rather by acting upstream of RAS activation via induction of EGFR internalisation . Knocking down Drosophila RalA from intestinal stem and progenitor cells leads to increased levels of plasma membrane-associated EGFR and decreased MAPK pathway activation. Importantly, in addition to impacting stem cell proliferation and damage-induced intestinal regeneration, this function of RAL GTPases drives EGFR-dependent tumorigenic growth in the intestine and in human mammary epithelium. Altogether, our results reveal previously unrecognised cellular and molecular contexts where RAL GTPases become essential mediators of EGFR-driven tissue homeostasis and malignant transformation. Results: RalA is required within ISCs to induce midgut adult midgut regeneration following damage by oral infection with Erwinia carotovora carotovora 15 (Ecc15) (Johansson et al., 2019). To achieve a global view of intestinal pathways affected by RalA, we performed a transcriptomic analysis by RNAseq of whole midguts from vehicle treated (Mock) or damaged (Ecc15 fed) control animals or following RalA knockdown in intestinal stem and progenitor cells using the escargot-gal4 driver (ISC/EB>) (Micchelli and Perrimon, 2006). Consistent with its effect on ISC proliferation (Johansson et al., 2019), RalA knockdown significantly impaired damage-induced upregulation of cell cycle genes in the midgut. Additionally, levels of multiple transcriptional targets of the EGFR/MAPK pathway (Golembo et al., 1996; Hsu et al., 2001; Jin et al., 2015; Meng and Biteau, 2015), such as argos (aos), rhomboid (rho), Sox21a and string (stg) were increased following Ecc15 infection in control midguts. The upregulation of these target genes was significantly impaired upon RalA knockdown.