Project description:Mutational status of KRAS in CRC is used to aid patient stratification for Cetuximab treatment. However, only a subset (10-40%) of patients with wt KRAS respond. We analyzed 40 mCRC tumors for Cetuximab response using a functional ex vivo platform. In the subset of non-responsive tumors, mutational (KRAS/BRAF and PIK3CA) and expression (AREG/EREG) analysis of key genes, transcriptomic profiling and GSEA were carried out to elucidate the molecular mechanisms underlying the response. Our analysis revealed deregulation of multiple pathways, notably Notch and Erbb2 and combined blockade of these two nodes elicited significant antitumor response. These findings collectively indicate the dependence of Cetuximab insensitive mCRC tumors on Notch and Erbb2 for survival and progression. 8 Primary tumors tested in ex vivo platform for response to Cetuximab were subjected to expression analysis
Project description:Mutational status of KRAS in CRC is used to aid patient stratification for Cetuximab treatment. However, only a subset (10-40%) of patients with wt KRAS respond. We analyzed 40 mCRC tumors for Cetuximab response using a functional ex vivo platform. In the subset of non-responsive tumors, mutational (KRAS/BRAF and PIK3CA) and expression (AREG/EREG) analysis of key genes, transcriptomic profiling and GSEA were carried out to elucidate the molecular mechanisms underlying the response. Our analysis revealed deregulation of multiple pathways, notably Notch and Erbb2 and combined blockade of these two nodes elicited significant antitumor response. These findings collectively indicate the dependence of Cetuximab insensitive mCRC tumors on Notch and Erbb2 for survival and progression.
Project description:Patients with metastatic colorectal cancer were enrolled for treatment with cetuximab monotherapy. Transcriptional profiling was conducted on RNA from pre-treatment metastatic site biopsies to identify genes whose expression correlates with best clinical responses. Keywords: comparison of disease control group versus non-responder group of patients
Project description:Anti-EGFR antibodies are effective in therapies for late-stage colorectal cancer (CRC); however, many tumours are unresponsive or develop resistance. We performed genomic analysis of intrinsic and acquired resistance to anti-EGFR therapy in prospectively collected tumour samples from 25 CRC patients receiving cetuximab (an EGFR inhibitor). Of 25 CRC patients, 13 displayed intrinsic resistance to cetuximab; 12 were intrinsically sensitive. We obtained six re-biopsy samples at acquired resistance from the intrinsically sensitive patients. NCOA4–RET and LMNA–NTRK1 fusions and NRG1 and GNAS amplifications were found in intrinsic-resistant patients. In cetuximab-sensitive patients, we found KRAS K117N and A146T mutations in addition to BRAF V600E, AKT1 E17K, PIK3CA E542K, and FGFR1 or ERBB2 amplifications. The comparison between baseline and acquired-resistant tumours revealed an extreme shift in variant allele frequency of somatic variants, suggesting that cetuximab exposure dramatically selected for rare resistant subclones that were initially undetectable. There was also an increase in epithelial-to-mesenchymal transition at acquired resistance, with a reduction in the immune infiltrate. Furthermore, characterization of an acquired-resistant, patient-derived cell line showed that PI3K/mTOR inhibition could rescue cetuximab resistance. Thus, we uncovered novel genomic alterations that elucidate the mechanisms of sensitivity and resistance to anti-EGFR therapy in metastatic CRC patients.
Project description: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.
Project description:In this study we want present a bank of metastatic colorectal cancer (mCRC) Patient Derived Organoids (PDOs) obtained from Patient Derived Xenografts (PDXs). These models are annotated with different omics to advance our understanding of CRC. We wanted to create a resource for the scientific community to assess the predictive reliability of these preclinical models. We performed comparative analyses between PDOs and matched PDXs to assess the similarities of these two platforms regarding molecular profiles and transcriptional classification. Moreover, we analyzed how these models respond to Cetuximab, a chimeric monoclonal antibody, normally given to patients after chemotherapy, that inhibits EGFR. After having assessed models’ reliability with Cetuximab, we aimed at identifying potential synergistic drugs to individuate new possible therapeutic prospects.
Project description:Colorectal cancer (CRC) is a commonly occurring cancer worldwide. Metastasis and recurrence are the major causes of cancer-related death. CRC progression is a multistep process, and extensive efforts have been made to identify the genomic and transcriptomic alterations that occur during this process. However, whether primary tumors and metastatic lesions possess distinct biological features remains unclear. We established 74 patient-derived organoids (PDOs) from primary tumors and patient-matched metastatic and recurrent lesions.
Project description:Cetuximab is an epidermal growth factor receptor (EGFR)-blocking antibody approved for treatment of metastatic colorectal cancer. We examined differences in global gene expression between the syngeneic DiFi colorectal cancer cells, and a subline of DiFi cells with acquired resistance to cetuximab (DiFi5). We used Affymetrix HG-U133A array to compare the expression pattern of genes that are up-regulated or down-regulated between the parental DiFi colorectal cancer cells and the cetuximab-resistant DiFi5 cells. We generated a cetuximab-resistant DiFi subline, termed DiFi5, by chronic exposure of parental DiFi cells to serially increased doses of cetuximab (from 0.5 nM to 5 nM) for over 1 year. The resulting DiFi5 subline exhibits significant resistance to cetuximab-induced apoptosis. After we confirmed that the phenotype was stable over a period of time of more than 6 months, the RNA from DiFi and DiFi5 cells were extracted and hybridized to an Affymetrix HG-U133A array according to the manufacturerâs instructions. Following the hybridization, the array was scanned using a laser confocal scanner, and microarray image data were analyzed using DNA-Chip Analyzer (dChip), version 1.3, by the Sequencing and Microarray Facility at MD Anderson Cancer Center.
Project description:10 cell lines (five cetuximab sensitive and five cetuximab resistant) were selected for gene copy number array analysis on the Affymetrix SNP 6.0 platform. 39 protein coding genes were amplified in cetuximab resistant cells and normal in sensitive cells, all present on genomic regions 11q22.1 or 5p13-15. Five genes were selected for quantitative PCR verification, namely, YAP1 and TRPC6 (11q22.1) and PDCD6, TPPP, and PTGER4 (5p13-15). An extended panel of totally 10 cetuximab resistant and 10 sensitive cell lines verified that YAP1 amplified cells are cetuximab resistant. YAP1 gene amplification was highly correlated to the YAP1 mRNA expression, which was significantly higher in cetuximab resistant cells than in sensitive. YAP1 downregulation resulted in increased cetuximab sensitivity in one of two cetuximab resistant cell lines investigated and growth inhibition in another. We conclude that YAP1 is a marker for cetuximab resistance in head and neck cancer. head and neck cancer cell lines with established cetuximab response were selected. 5 cetuximab resistant cell lines and 5 cetuximab sensitive cell lines were selected for gene genome wide gene copy number analysis on the Affymetrix SNP6.0 array