Understanding the mechanisms of resistance to BRAF inhibitors in colorectal cancer
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE248414 | GEO | 2025/09/01
REPOSITORIES: GEO
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Project description:Patients with BRAF-mutated colorectal cancer (BRAFV600E CRC) are currently treated by a combination of BRAF inhibitor and anti-EGFR antibody with or without MEK inhibitor. A fundamental problem in treating patients with BRAFV600E CRC is intrinsic and/or acquired resistance to this combination therapy. By screening 78 compounds, we identified tretinoin, a retinoid, as a compound that synergistically enhances the antiproliferative effect of a combination of BRAF inhibition and MEK inhibition with or without EGFR inhibition on BRAFV600E CRC cells. This synergistic effect was also exerted by other retinoids. Tretinoin, added to BRAF inhibitor and MEK inhibitor, upregulated PARP, BAK, and p-H2AX. When either RARα or RXRα was silenced, the increase in cleaved PARP expression by the addition of TRE to ENC/BIN or ENC/BIN/CET was canceled. Our results suggest that the mechanism of the synergistic antiproliferative effect involves modulation of the Bcl-2 family and the DNA damage response that affects apoptotic pathways, and this synergistic effect is induced by RARα- or RXRα-mediated apoptosis. Tretinoin also enhanced the antitumor effect of a combination of BRAF inhibitor and anti-EGFR antibody with or without MEK inhibitor in a BRAFV600E CRC xenograft mouse model. Our data provide a rationale for developing retinoids as a new combination agent to overcome resistance to the combination therapy for patients with BRAFV600E CRC.
2024-11-06 | GSE269881 | GEO
Project description:Patients with BRAF-mutated colorectal cancer (BRAFV600E CRC) are currently treated by a combination of BRAF inhibitor and anti-EGFR antibody with or without MEK inhibitor. A fundamental problem in treating patients with BRAFV600E CRC is intrinsic and/or acquired resistance to this combination therapy. By screening 78 compounds, we identified tretinoin, a retinoid, as a compound that synergistically enhances the antiproliferative effect of a combination of BRAF inhibition and MEK inhibition with or without EGFR inhibition on BRAFV600E CRC cells. This synergistic effect was also exerted by other retinoids. Tretinoin, added to BRAF inhibitor and MEK inhibitor, upregulated PARP, BAK, and p-H2AX. When either RARα or RXRα was silenced, the increase in cleaved PARP expression by the addition of TRE to ENC/BIN or ENC/BIN/CET was canceled. Our results suggest that the mechanism of the synergistic antiproliferative effect involves modulation of the Bcl-2 family and the DNA damage response that affects apoptotic pathways, and this synergistic effect is induced by RARα- or RXRα-mediated apoptosis. Tretinoin also enhanced the antitumor effect of a combination of BRAF inhibitor and anti-EGFR antibody with or without MEK inhibitor in a BRAFV600E CRC xenograft mouse model. Our data provide a rationale for developing retinoids as a new combination agent to overcome resistance to the combination therapy for patients with BRAFV600E CRC.
2024-11-06 | GSE269880 | GEO
Project description:Background: BRAF activating mutations occur in approximately 10% of metastatic colorectal cancer (CRCs) and are associated with worse prognosis in part due to an inferior response to standard chemotherapy. Standard of care for patients with refractory metastatic BRAFV600E CRC is treatment with BRAF and EGFR inhibitors and recent FDA approval was given to use these inhibitors in combination with chemotherapy for patients with treatment naïve metastatic BRAFV600E CRC. Lineage plasticity to neuroendocrine cancer is an emerging mechanism of targeted therapy resistance in several cancer types. Enteroendocrine cells (EECs), the neuroendocrine cell of the intestine, are uniquely present in BRAFV600E CRC as compared to BRAF wildtype CRC. Methods: BRAF plus EGFR inhibitor treatment induced changes in cell composition were determined by gene expression, imaging and single cell approaches in multiple models of BRAF mutant CRC. Furthermore, multiple clinically relevant inhibitors of the lysine demethylase LSD1 were tested to determine which inhibitor blocked the changes in cell composition. Results: Combined BRAF and EGFR inhibition enriched for EECs in all BRAF mutant CRC models tested. Additionally, EECs and other secretory cell types were enriched in a subset of BRAFV600E CRC patient samples following targeted therapy. Importantly, inhibition of LSD1 with a clinically relevant inhibitor attenuated targeted therapy-induced EEC enrichment through blocking the interaction of LSD1, CoREST2 and STAT3. Conclusions: Our findings that BRAF plus EGFR inhibition induces lineage plasticity in BRAFV600E CRC represents a new paradigm for how resistance to BRAF plus EGFR inhibition occurs. Additionally, our finding that LSD1 inhibition blocks lineage plasticity has the potential to improve responses to BRAF plus EGFR inhibitor therapy in patients.
2025-04-30 | GSE290028 | GEO
Project description:We performed gene expression profiling in the human papillary thyroid carcinoma (PTC) derived cell line BCPAP harboring BRAFV600E mutation following the treatment with BRAF selective inhibitors.
2021-07-13 | GSE171483 | GEO
Project description:Erythropoiesis is a crucial part in hematopoietic system, while facing disruptions from various diseases conditions. Anemia and blood shortages has become global challenges, with current finite pharmacological options like EPO or glucocorticoids having limitations, especially in genetic anemias like Diamond-Blackfan anemia (DBA), calling for novel candidates in stimulating the erythropoiesis. We designed the primary human hematopoietic stem and progenitor cells (HSPCs) chemicals screening system in erythropoiesis and unexpectedly discovered a BRAF inhibitor, effectively against BRAFV600E mutant cancers, delaying erythroid differentiation while promoting progenitors’ proliferation. Further research demonstrated its efficacy in cytokine-restricted conditions and in samples from erythroid disorder patients. Mechanistically, BRAF inhibitors paradoxically activated the RAF-MEK-ERK/MAPK pathway. Unlike oncogenic BRAFV600E impaired hematopoiesis and erythropoiesis via AP-1 hyperactivation, BRAF inhibitors minimally affected HSPCs self-renewal and differentiation. In vivo studies further exhibited BRAF inhibitors' potential to enhance human hematopoiesis and erythropoiesis in severe immunodeficient mouse models and alleviate anemia symptoms in Rpl11 haploinsufficiency DBA models and other anemia models. This discovery sheds light on the MAPK pathway's role in hematopoiesis, making BRAF inhibitors a novel clinically therapeutic choice in improving hematopoietic reconstitution and the recovery of anemias like DBA.
2024-12-03 | GSE261118 | GEO
Project description:Erythropoiesis is a crucial part in hematopoietic system, while facing disruptions from various diseases conditions. Anemia and blood shortages has become global challenges, with current finite pharmacological options like EPO or glucocorticoids having limitations, especially in genetic anemias like Diamond-Blackfan anemia (DBA), calling for novel candidates in stimulating the erythropoiesis. We designed the primary human hematopoietic stem and progenitor cells (HSPCs) chemicals screening system in erythropoiesis and unexpectedly discovered a BRAF inhibitor, effectively against BRAFV600E mutant cancers, delaying erythroid differentiation while promoting progenitors’ proliferation. Further research demonstrated its efficacy in cytokine-restricted conditions and in samples from erythroid disorder patients. Mechanistically, BRAF inhibitors paradoxically activated the RAF-MEK-ERK/MAPK pathway. Unlike oncogenic BRAFV600E impaired hematopoiesis and erythropoiesis via AP-1 hyperactivation, BRAF inhibitors minimally affected HSPCs self-renewal and differentiation. In vivo studies further exhibited BRAF inhibitors' potential to enhance human hematopoiesis and erythropoiesis in severe immunodeficient mouse models and alleviate anemia symptoms in Rpl11 haploinsufficiency DBA models and other anemia models. This discovery sheds light on the MAPK pathway's role in hematopoiesis, making BRAF inhibitors a novel clinically therapeutic choice in improving hematopoietic reconstitution and the recovery of anemias like DBA.
2024-12-03 | GSE261117 | GEO
Project description:Erythropoiesis is a crucial part in hematopoietic system, while facing disruptions from various diseases conditions. Anemia and blood shortages has become global challenges, with current finite pharmacological options like EPO or glucocorticoids having limitations, especially in genetic anemias like Diamond-Blackfan anemia (DBA), calling for novel candidates in stimulating the erythropoiesis. We designed the primary human hematopoietic stem and progenitor cells (HSPCs) chemicals screening system in erythropoiesis and unexpectedly discovered a BRAF inhibitor, effectively against BRAFV600E mutant cancers, delaying erythroid differentiation while promoting progenitors’ proliferation. Further research demonstrated its efficacy in cytokine-restricted conditions and in samples from erythroid disorder patients. Mechanistically, BRAF inhibitors paradoxically activated the RAF-MEK-ERK/MAPK pathway. Unlike oncogenic BRAFV600E impaired hematopoiesis and erythropoiesis via AP-1 hyperactivation, BRAF inhibitors minimally affected HSPCs self-renewal and differentiation. In vivo studies further exhibited BRAF inhibitors' potential to enhance human hematopoiesis and erythropoiesis in severe immunodeficient mouse models and alleviate anemia symptoms in Rpl11 haploinsufficiency DBA models and other anemia models. This discovery sheds light on the MAPK pathway's role in hematopoiesis, making BRAF inhibitors a novel clinically therapeutic choice in improving hematopoietic reconstitution and the recovery of anemias like DBA.
2024-09-09 | PXD055730 |
Project description:Metastatic BRAFV600E colorectal cancer (CRC) confers poor prognosis and represents a therapeutic bottleneck. To identify resistance mechanisms of the mitogen-activated protein kinase (MAPK) pathway in BRAFV600E CRC, we perform genome-wide CRISPR-Cas9 screening and discover that targeting glutathione peroxidase 4 (GPX4) overcomes resistance to BRAF inhibitor (BRAFi) combined with or without epidermal growth factor receptor inhibitor (EGFRi) in BRAFV600E CRC. Specifically, BRAFi ± EGFRi upregulates GPX4 expression, which antagonizes therapy-induced ferroptosis. Moreover, polo-like kinase 1 (PLK1) substrate activation promotes PLK1 translocation to the nucleus, activating chromobox protein homolog 8 (CBX8) phosphorylation at Ser265 to drives GPX4 expression. Targeting PLK1 enhances BRAFi ± EGFRi inhibition and triggers ferroptosis in vitro, vivo, organoid, and patient-derived xenograft model. Collectively, we demonstrate a PLK1–CBX8–GPX4 signaling axis that relays the ferroptosis mechanism of therapeutic resistance and propose a clinically actionable strategy to overcome BRAFi ± EGFRi resistance in BRAFV600E CRC.
2025-02-28 | GSE283185 | GEO
Project description:Mutations in the BRAF proto-oncogene, which encodes the B-Raf kinase, are associated with more aggressive, less-differentiated and therapy-resistant colorectal cancers (CRC). However, the molecular mechanisms responsible for these correlations remain unknown. Here, we report the characterization of human isogenic CRC cell line models (Caco-2, HT29, Colo-205) in which we modulate the expression of the B-RafV600E oncoprotein either by conditional cDNA or shRNA expression. Using these models in conventional and three dimensional tissue culture systems, we demonstrate that genetic depletion of endogenous B-RafV600E decreases cellular motility and invasion, while it induces hallmarks of differentiated epithelia such as the formation of functional adherens and tight junctions. Importantly, these effects are recapitulated by exposing these lines to B-Raf (PLX4720, vemurafenib, dabrafenib) or MEK inhibitors (trametinib). Furthermore, loss of endogenous B-RafV600E in HT29 xenografts does not only stall tumor growth, but also induces epithelial structures with marked expression of Cdx-2, a prognostic marker and master regulator of intestinal morphogenesis. By performing the first transcriptome profiles of B-Raf inhibitor treated 3D cultures of a primary adenocarcinoma and a metastasis derived CRC cell line, we establish functional links between B-RafV600E and proteins of known and potentially new prognostic relevance. We propose that B-Raf/MEK/ERK pathway inhibitors could be used to induce CRC differentiation and thereby to limit metastatic disease. To measure the time resolved gene responses, RNA was isolated from PLX4720 or DMSO treated Colo-205 and HT29 3D culture cell lysates at days 1,3 and 10 and days 1,3, and 8, respectively. The time points for HT29 cells were taken in biological duplicates.
2014-12-21 | E-GEOD-50791 | biostudies-arrayexpress
Project description:The first clinical trial testing the combination of targeted therapy with a BRAF inhibitor vemurafenib and immunotherapy with a CTLA-4 antibody ipilimumab was terminated early due to significant liver toxicities, possibly due to paradoxical activation of the MAPK pathway by BRAF inhibitors in tumors with wild type BRAF. MEK inhibitors can potentiate the MAPK inhibition in tumor, while potentially alleviating the unwanted paradoxical MAPK activation. With a mouse model of syngeneic BRAFV600E driven melanoma (SM1), we tested whether the addition of the MEK inhibitor trametinib would enhance the immunosensitization effects of the BRAF inhibitor dabrafenib. Combination of dabrafenib and trametinib with pmel-1 adoptive cell transfer (ACT) showed complete tumor regression. Bioluminescent imaging and tumor infiltrating lymphocyte (TIL) phenotyping showed increased effector infiltration to tumors with dabrafenib, trametinib or dabrafenib plus trametinib with pmel-1 ACT combination. Intracellular IFN gamma staining of the TILs and in vivo cytotoxicity studies showed trametinib was not detrimental to the effector functions in vivo. Dabrafenib increased tumor associated macrophages and T regulatory cells (Tregs) in the tumors, which can be overcome by addition of trametinib. Microarray analysis revealed increased melanoma antigen, MHC expression, and global immune-related gene upregulation with the triple combination therapy. Given the up-regulation of PD-L1 seen with dabrafenib and/or trametinib combined with antigen specific ACT, we tested the triple combination of dabrafenib, trametinib with anti-PD1 therapy, and observed superior anti-tumor effect to SM1 tumors. Our findings support the testing of these combinations in patients with BRAFV600E mutant metastatic melanoma. SM1 tumors were implanted into C57BL/6 mice. Mice were treated by ACT of pmel-1 splenocytes or C57BL/6 splenocytes as control. Pmel-1 treated mice were additionally treated with either vehicle, dabrafenib, trametinib, or combination of both drugs and control mice were treated with vehicle or combination of both drugs.
2014-12-12 | E-GEOD-64102 | biostudies-arrayexpress