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Gene expression changes associated with acquired resistance to anti-EGFR therapy (cetuximab) in colorectal cancer cells

ABSTRACT: Despite the implementation of personalized medicine, patients with metastatic CRC (mCRC) still have a dismal overall survival due to the frequent occurrence of acquired resistance mechanisms thereby leading to clinical relapse. Understanding molecular mechanisms that support acquired resistance to anti-EGFR targeted therapy in mCRC is therefore clinically relevant and key to improving patient outcomes. Here, we observe distinct metabolic changes between cetuximab-resistant CRC cell populations, with in particular an increased glycolytic activity in KRAS-mutant cetuximab-resistant LIM1215 but not in KRAS-amplified resistant DiFi cells. We show that cetuximab-resistant LIM1215 cells have the capacity to recycle glycolysis-derived lactate to sustain their growth capacity. This is associated with an upregulation of the lactate importer MCT1 at both transcript and protein levels. Pharmacological inhibition of MCT1, with AR-C155858, reduces the uptake and oxidation of lactate and impairs growth capacity in cetuximab-resistant LIM1215 cells. This study identifies MCT1-dependent lactate utilization as a clinically actionable, metabolic vulnerability to overcome KRAS-mutant-mediated acquired resistance to anti-EGFR therapy in CRC.

ORGANISM(S): Homo sapiens

PROVIDER: GSE262796 | GEO | 2024/07/02

REPOSITORIES: GEO

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Project description:KRAS mutation is a negative predictive factor for treatment with anti-epidermal growth factor receptor (EGFR) antibodies in metastatic colorectal cancer (mCRC). Novel predictive markers are required to further improve the selection of patients for this treatment. Here, we assessed the influence of modification of KRAS by gene copy number aberration (CNA) and microRNAs (miRNAs) in correlation to clinical outcome in mCRC patients treated with cetuximab in combination with chemotherapy and bevacizumab. Formalin-fixed paraffin-embedded primary tumour tissue was used from 34 mCRC patients in a phase III trial, who were selected based upon their good (n=17) or poor (n=17) progression-free survival (PFS) upon treatment with cetuximab in combination with capecitabine, oxaliplatin, and bevacizumab. Gene copy number at the KRAS locus was assessed using high resolution genome-wide array CGH and the expression levels of 17 miRNAs targeting KRAS were determined by real-time PCR. Good response was associated with 12p12.1 copy number loss, even in patients with a KRAS mutation, while copy number gain in wild-type KRAS patients was correlated with a poor response. In KRAS mutated tumours increased miR-200b and decreased miR-143 expression were associated with a good response. In wild-type KRAS patients, miRNA expression did not predict response in a multivariate model. Thus, assessment of KRAS CNA and miRNAs targeting KRAS might further optimize the selection of patients eligible for anti-EGFR therapy. Copy number detection was performed using NimbleScan and Nexus software Formalin-fixed paraffin-embedded primary tumour tissue was used from 34 metastisized colorectal cancer patients in a phase III trial (CKTO 2005-02; ClinTrials.gov NCT00208546) of the Dutch Colorectal Cancer Group (DCCG), who were selected based upon their good (n=17) or poor (n=17) progression-free survival (PFS) upon treatment with cetuximab in combination with capecitabine, oxaliplatin, and bevacizumab.

Project description:Colorectal cancer (CRC) is still one of the most common causes of cancer-related death worldwide (World Health Organization, Fact sheet NM-BM-0297, October 2011). Though, therapeutic options improved over the past years, the prognosis of metastatic colorectal cancer (mCRC) remains poor with a median survival of 18-21 months. Monoclonal antibodies targeting the epidermal growth factor receptor (EGFR) are used for the palliative treatment of metastatic colorectal cancer (mCRC) carrying a KRAS-wildtype. Among the tumors with a KRAS-wildtype, only 35% respond, and alterations of other signaling molecules and pathways modulate therapeutic response. In this study we analyzed the effect of KRAS-mutations on intracellular signaling cascades to find new therapeutic approaches for patients with mCRC. Reverse-phase protein array and gene array technology was applied to sixteen adenocarcinomas of the sigmoid colon carrying either wildtype (n=8) or mutant (n=8) KRAS. Differential expression was validated on 49 sigmoid cancers by RT-PCR, Western blot and immunohistochemistry. In a screening for members of signaling pathways known to have a high impact on tumor development in colon cancer, we found 14 proteins downregulated in tumors with mutated KRAS. Subsequently, we compared the data of the protein arrays with the results of gene expression arrays performed with the same samples. We confirmed the differential expression of eight genes as a function of the KRAS genotype of the tumor. To further validate the differential expression of these candidates, we performed quantitative expression analysis and immunohistochemical staining of an independent validation series comprising 49 CRC patient samples. It was clearly demonstrated that the expression of EGFR is decreased in colorectal carcinomas with a mutant KRAS genotype. mRNA was obtained from 16 patients with colorectal cancer (8 with and 8 without KRAS-mutation). mRNA was extracted from neoplastic and non-neoplastic colon mucosa and analyzed separately by Affymetrix Human Gene 1.1 ST GeneChips finally generating 32 separate data sets.

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Gene expression changes associated with acquired resistance to anti-EGFR therapy (cetuximab) in colorectal cancer cells

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