{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["14(21)"],"submitter":["Turner E"],"pubmed_abstract":["<i>BRAF V600E</i> mutation drives uncontrolled cell growth in most melanomas. While <i>BRAF V600E</i> tumors are initially responsive to BRAF inhibitors, prolonged treatment results in inhibitor resistance and tumor regrowth. Clinical data have linked the <i>NRAS Q61K</i>, <i>KRAS G13D</i> and <i>MEK1 Q56P</i> mutations to the BRAF inhibitor resistance. However, development of novel therapeutics is hindered by the lack of relevant isogeneic cell models. We employed CRISPR/Cas9 genome engineering to introduce <i>NRAS Q61K</i>, <i>KRAS G13D</i> and <i>MEK1 Q56P</i> mutations into the A375 melanoma cell line with endogenously high expression of <i>BRAF V600E</i>. The resulting isogenic cell lines are resistant to BRAF inhibitors. The A375 <i>MEK1 Q56P</i> isogenic cells are additionally resistant to MEK inhibitors as single agent, but interestingly, these cells become sensitive to MEK/BRAF inhibitor combo. Our results suggest that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. Interestingly, the <i>KRAS G13D</i> isogenic line displays elevated PD-L1 expression suggesting the <i>KRAS G13D</i> mutation could be a potential indication for immunotherapy. Overall, these three novel isogenic cell models with endogenous level <i>RAS</i> and <i>MEK1</i> point mutations provide direct bio-functional evidence demonstrating that acquiring a drug-resistant gene drives tumor cell survival and may simultaneously introduce new indications for combo therapy or immunotherapy in the clinic."],"journal":["Cancers"],"pagination":["5449"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9655013"],"repository":["biostudies-literature"],"pubmed_title":["CRISPR/Cas9 Edited RAS & MEK Mutant Cells Acquire BRAF and MEK Inhibitor Resistance with MEK1 Q56P Restoring Sensitivity to MEK/BRAF Inhibitor Combo and KRAS G13D Gaining Sensitivity to Immunotherapy."],"pmcid":["PMC9655013"],"pubmed_authors":["Tian F","Chen L","Gu Z","Foulke JG","Turner E"],"additional_accession":[]},"is_claimable":false,"name":"CRISPR/Cas9 Edited RAS & MEK Mutant Cells Acquire BRAF and MEK Inhibitor Resistance with MEK1 Q56P Restoring Sensitivity to MEK/BRAF Inhibitor Combo and KRAS G13D Gaining Sensitivity to Immunotherapy.","description":"<i>BRAF V600E</i> mutation drives uncontrolled cell growth in most melanomas. While <i>BRAF V600E</i> tumors are initially responsive to BRAF inhibitors, prolonged treatment results in inhibitor resistance and tumor regrowth. Clinical data have linked the <i>NRAS Q61K</i>, <i>KRAS G13D</i> and <i>MEK1 Q56P</i> mutations to the BRAF inhibitor resistance. However, development of novel therapeutics is hindered by the lack of relevant isogeneic cell models. We employed CRISPR/Cas9 genome engineering to introduce <i>NRAS Q61K</i>, <i>KRAS G13D</i> and <i>MEK1 Q56P</i> mutations into the A375 melanoma cell line with endogenously high expression of <i>BRAF V600E</i>. The resulting isogenic cell lines are resistant to BRAF inhibitors. The A375 <i>MEK1 Q56P</i> isogenic cells are additionally resistant to MEK inhibitors as single agent, but interestingly, these cells become sensitive to MEK/BRAF inhibitor combo. Our results suggest that resistance in the NRAS and MEK isogenic lines is driven by constitutive MEK/ERK signaling, while the resistance in the KRAS isogenic line is driven by EGFR overexpression. Interestingly, the <i>KRAS G13D</i> isogenic line displays elevated PD-L1 expression suggesting the <i>KRAS G13D</i> mutation could be a potential indication for immunotherapy. Overall, these three novel isogenic cell models with endogenous level <i>RAS</i> and <i>MEK1</i> point mutations provide direct bio-functional evidence demonstrating that acquiring a drug-resistant gene drives tumor cell survival and may simultaneously introduce new indications for combo therapy or immunotherapy in the clinic.","dates":{"release":"2022-01-01T00:00:00Z","publication":"2022 Nov","modification":"2025-04-25T23:31:49.795Z","creation":"2025-04-06T09:22:00.596Z"},"accession":"S-EPMC9655013","cross_references":{"pubmed":["36358868"],"doi":["10.3390/cancers14215449"]}}