Project description:Phosphoinositide-3-kinase (PI3K)-α inhibitors are clinically active in squamous carcinoma (SCC) of the head and neck (H&N) bearing mutations or amplification of PIK3CA. We aimed to identify potential mechanism of resistance and have observed that SCCs cells overcome the antitumor effects of the PI3Kα inhibitor BYL719 by maintaining PI3K-independent activation of the mammalian target of rapamycin (mTOR). The persistent mTOR activation is mediated by the tyrosine kinase receptor AXL. We found that AXL is overexpressed in resistant tumors, dimerizes with the epidermal growth factor receptor (EGFR), phosphorylates EGFR tyrosine 1173, resulting in activation of phospholipase Cγ (PLCγ)- protein kinase C (PKC) that, in turn, activates mTOR. Finally, simultaneous treatment with PI3Kα and either EGFR, AXL or PKC inhibitors reverts this resistance. RNAseq from acquired resistant cells CAL33B, K180B were compared to their parental counterpart CAL33 and K180, respectively. K180 is a shortcut of KYSE180, and B stands for BYL719. Duplicate of parental sensitive cells and K180B, and triplicate for CAL33B.
Project description:Phosphoinositide-3-kinase (PI3K)-α inhibitors are clinically active in squamous carcinoma (SCC) of the head and neck (H&N) bearing mutations or amplification of PIK3CA. We aimed to identify potential mechanism of resistance and have observed that SCCs cells overcome the antitumor effects of the PI3Kα inhibitor BYL719 by maintaining PI3K-independent activation of the mammalian target of rapamycin (mTOR). The persistent mTOR activation is mediated by the tyrosine kinase receptor AXL. We found that AXL is overexpressed in resistant tumors, dimerizes with the epidermal growth factor receptor (EGFR), phosphorylates EGFR tyrosine 1173, resulting in activation of phospholipase Cγ (PLCγ)- protein kinase C (PKC) that, in turn, activates mTOR. Finally, simultaneous treatment with PI3Kα and either EGFR, AXL or PKC inhibitors reverts this resistance.
Project description:AXL mediates resistance to PI3Kα inhibition by activating the EGFR/PKC/mTOR axis in head and neck and esophageal squamous cell carcinomas.
Project description:Elevated expression and activity of the epidermal growth factor receptor (EGFR) is associated with development and progression of head and neck cancer (HNC) and a poor prognosis. Clinical trials with EGFR tyrosine kinase inhibitors (TKIs; eg. erlotinib) have been disappointing in HNC. To investigate the mechanisms mediating resistance to these agents, we developed a HNC cell line (HN5-ER) with acquired erlotinib resistance. In contrast to parental HN5 HNC cells, HN5-ER cells exhibited an epithelial-mesenchymal (EMT) phenotype with increased migratory potential, reduced E-cadherin and epithelial-associated miRNAs, and elevated vimentin expression. Phosphorylated RTK profiling identified Axl activation in HN5-ER cells. Growth and migration of HN5-ER cells was blocked with a specific Axl inhibitor, R428, and R428 re-sensitized HN5-ER cells to erlotinib. Microarray analysis of HN5-ER cells confirmed the EMT phenotype associated with acquired erlotinib resistance, and identified activation of gene expression associated with cell migration and inflammation pathways. Moreover, increased expression and secretion of interleukin (IL)-6 and IL-8 in HN5-ER cells suggested a role for inflammatory cytokine signaling in EMT and erlotinib resistance. Expression of the tumor suppressor miR-34a was reduced in HN5-ER cells and increasing its expression abrogated Axl expression and reversed erlotinib resistance. Finally, analysis of 302 HNC patients revealed that high tumor Axl mRNA expression was associated with poorer survival (HR 1.66, p=0.007). In summary, our results identify Axl as a key mediator of acquired erlotinib resistance in HNC and suggest that therapeutic inhibition of Axl by small molecule drugs or specific miRNAs might overcome anti-EGFR therapy resistance. Differential gene expression between parental and acquired erlotinib resistant head and neck cancer cell lines of HN5.
Project description:We used ChIP-seq to map the binding sites of wild-type and mutant KLF5. In addition, by performing H3K27ac ChIP-seq, we mapped the enhancer regions in cell lines of head and neck squamous cell carcinomas, esophageal carcinomas, and stomach adenocarcinomas.
Project description:Protein Kinase C alpha (PKC) is a critical mediator of cell signaling and cancer growth. We show that PKC inhibitors decrease proliferation in squamous cell carcinoma of the head and neck (SCCHN) cells and abrogate growth of SCCHN tumors in mouse xenografts. Analysis of gene expression arrays reveals that PKC regulates cell cycle genes required for DNA synthesis. In particular, PKC increases cyclin E protein expression, cyclinE/cdk2 complex formation, and transcription of cyclin E and E2F target genes. Consistent with this mechanism, expression of cyclin E rescues the block in DNA synthesis caused by PKC inhibition. In SCCHN tissue, PKC and cyclin E expression increase progressively from normal and dysplastic to malignant human head and neck tissue. Furthermore, PKCÂ expression correlates with poor prognosis in SCCHN. These results demonstrate that PKC regulates growth by stimulating DNA synthesis through cyclin E and E2F and identify PKC as a therapeutic target that is highly expressed in aggressive SCCHN. Experiment Overall Design: 9 samples composed of treated replicates at three time points
Project description:Protein Kinase C alpha (PKC) is a critical mediator of cell signaling and cancer growth. We show that PKC inhibitors decrease proliferation in squamous cell carcinoma of the head and neck (SCCHN) cells and abrogate growth of SCCHN tumors in mouse xenografts. Analysis of gene expression arrays reveals that PKC regulates cell cycle genes required for DNA synthesis. In particular, PKC increases cyclin E protein expression, cyclinE/cdk2 complex formation, and transcription of cyclin E and E2F target genes. Consistent with this mechanism, expression of cyclin E rescues the block in DNA synthesis caused by PKC inhibition. In SCCHN tissue, PKC and cyclin E expression increase progressively from normal and dysplastic to malignant human head and neck tissue. Furthermore, PKC expression correlates with poor prognosis in SCCHN. These results demonstrate that PKC regulates growth by stimulating DNA synthesis through cyclin E and E2F and identify PKC as a therapeutic target that is highly expressed in aggressive SCCHN. Keywords: time course; dose response
Project description:To evaluate the efficacy and safety of nimotuzumab in the treatment of EGFR-amplified advanced pan solid tumors (Lung/Esophageal/Gastric/Pancreatic /Colorectal / Head and neck Cervical).
Project description:Protein Kinase C alpha (PKC) is associated with progression and poor prognosis in head and neck cancer. Previous studies have demonstrated that PKC sustains the proliferative signal by increasing cyclin E expression, leading to enhanced E2F target gene transcription and DNA synthesis. Here we show that PKC increases DNA synthesis through inhibition of the microRNA, miR-15a, upregulating translation of its target cyclin E. Importantly, gene expression and qRT-PCR analysis of primary squamous cell carcinoma tumors of the head and neck (SCCHN) reveals a significant negative correlation between PKCï¡ and miR-15a levels. In contrast to normal cell cycle initiation, PKC decreases microRNA expression, leading first to increased cyclin E protein followed by enhanced transcription of cyclin E and other DNA synthesis mediators. These results identify a signaling network regulated by PKC whereby constitutive kinase activation switches the system to feed forward, overriding normal regulation of cell cycle progression through a post-transcriptional mechanism involving microRNAs. This reprogramming of the network is likely a more general phenomenon that can account for the oncogenic potency of established signaling pathways. Keywords: miRNA; dose response; cancer 6 treated samples across two time points hybridized to paired time 0, untreated controls
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.