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
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.
Project description:To determine the mechanism of cetuximab-resistance in head and neck cancer, a cetuximab-sensitive cell line (SCC1) and its cetuximab-resistant derivative (1Cc8) were analyzed for differentially expressed genes using DNA microarrays. 900 differentially expressed genes were found using the statistical cut-off point of one-way ANOVA with FDR less than 1%.
Project description:To determine the mechanism of cetuximab-resistance in head and neck cancer, a cetuximab-sensitive cell line (SCC1) and its cetuximab-resistant derivative (1Cc8) were analyzed for differentially expressed genes using DNA microarrays. 900 differentially expressed genes were found using the statistical cut-off point of one-way ANOVA with FDR less than 1%. The SCC1 and 1Cc8 cell lines were grown in biological triplicates. Total RNA was isolated and array experiments were performed. The supplementary file 'GSE21483_differentially_expressed_genes.txt' includes the list of differentially expressed genes that were identified.
Project description:We deciphered molecular mechanisms associated with acquired resistance to anti-EGFR targeted therapy in head and neck squamous cell carcinoma (HNSCC) by comparing gene expression profiles in cetuximab-sensitive and -resistant patient-derived xenograft (PDX) models of HNSCC. We generated and validated several HNSCC PDX models. Resistance mechanisms to anti-EGFR therapy were investigated in one of these PDX models (UCLHN04). First, sensitivity to cetuximab treatment was tested. This model showed high sensitivity to this drug. We induced acquired resistance to anti-EGFR therapy in this sensitive model by treating it chronically with anti-EGFR monoclonal antibody (cetuximab, 30 mg/kg/week) until resistance ensues. RNA-seq analysis was performed on samples coming from untreated and cetuximab-resistant PDX, revealing major changes of expression at the mRNA level.
Project description:Unraveling the underlying mechanisms of cetuximab resistance in head and neck squamous cell carcinoma (HNSCC) is of major importance as many tumors remain non-responsive or become resistant. Out microarray results suggest that resistant cells still exhibit RAS-MAPK pathway signaling contributing to drug resistance, as witnessed by low expression of DUSP 5 and DUSP6, negative regulators of ERK1/2, and increased expression of AURKB, a key regulator of mitosis. Therefore, interrupting the RAS-MAPK pathway by an ERK1/2 inhibitor (apigenin) or an AURKB inhibitor (barasertib) might be a new strategy for overcoming cetuximab resistance in HNSCC 4 head and neck squamous cell carcinoma (HNSCC) cell lines were treated with either 15 nM cetuximab or PBS during 13 hours. For each cell line, differential gene expression was assessed between cetuximab and PBS treatments.
Project description:Expression analysis (RNA-seq) and RPPA data (see publication) of head and neck cancer patient-derived xenographs (PDXs) revealed Sox-2 and Cav-1 expression to be biomarker determinants of head and neck cancer patient tumor response to cetuximab (EGFR inhibitor) treatment.
Project description:Most head and neck cancer (HNC) patients are resistant to cetuximab, an antibody against the epithelial growth factor receptor. Such therapy resistance is known to be mediated, in part, by stromal cells surrounding the tumor cells; however, the mechanisms underlying such a resistance phenotype remain unclear. To identify the mechanisms underlying cetuximab resistance in an unbiased manner, RNA-sequencing (RNA-seq) of HNC patient-derived xenografts (PDXs) was performed. Comparing the gene expression of HNC-PDXs before and after treatment with cetuximab indicated that the TGF-beta signaling pathway was upregulated in the stromal cells of PDXs that progressed to cetuximab (CetuximabProg-PDX). However, in PDXs that were extremely sensitive to cetuximab, and when tumors shrunk following cetuximab treatment (CetuximabSen-PDX), the TGF-beta pathway was downregulated in the stromal compartment. Histopathological analysis of PDXs showed that in CetuximabProg-PDX, TGF-beta-activation was detected in cancer-associated fibroblasts (CAFs). These TGF-beta-activated CAFs were sufficient to limit cetuximab efficacy in vitro and in vivo. Moreover, blocking the TGF-beta pathway using the SMAD3 inhibitor, SIS3, enhanced cetuximab efficacy and prevented the progression of CetuximabProg-PDX. Altogether, our findings indicate, for the first time, that TGF-beta-activated CAFs play a role in limiting cetuximab efficacy in HNC.
Project description:To investigate the mechanism of cetuximab resistance in head and neck squamous cell carcinoma (HNSCC), we performed single-cell RNA sequencing analysis in biopsy from two HNSCC patients before and after cetuximab treatment.