Project description:Acquired resistance to cancer drug therapies almost always occurs in advanced-stage patients even following a significant response to treatment. In addition to mutational mechanisms, various non-mutational resistance mechanisms have now been recognized. We previously described a chromatin-mediated subpopulation of reversibly drug-tolerant persisters (DTPs) that is dynamically maintained within a wide variety of tumor cell populations. Here, we explored a potential role for microRNAs in such transient drug tolerance. Functional screening of 879 human microRNAs revealed miR-371-3p as a potent suppressor of drug tolerance. PRDX6 (peroxiredoxin 6) was identified as a key target of miR-371-3p in establishing drug tolerance by regulating PLA2/PKCα activity and reactive oxygen species. PRDX6 expression is associated with poor prognosis in cancers of multiple tissue origins. These findings implicate miR-371-3p as a suppressor of PRDX6 and suggest that co-targeting of PRDX6 or modulating miR-371-3p expression together with targeted cancer therapies may delay or prevent acquired drug resistance. Drug tolerant persisters (DTPs) generated in response to erlotinib treatment were the basis for RNA extraction and hybridization on Affymetrix microarrays. PC9 cells were treated with DMSO or Erlotinib for 9 days to generate DTPs, then RNA was isolated for analyzing the differential gene expression pattern in DTPs compared to parental cells.
Project description:Acquired resistance to cancer drug therapies almost always occurs in advanced-stage patients even following a significant response to treatment. In addition to mutational mechanisms, various non-mutational resistance mechanisms have now been recognized. We previously described a chromatin-mediated subpopulation of reversibly drug-tolerant persisters (DTPs) that is dynamically maintained within a wide variety of tumor cell populations. Here, we explored a potential role for microRNAs in such transient drug tolerance. Functional screening of 879 human microRNAs revealed miR-371-3p as a potent suppressor of drug tolerance. PRDX6 (peroxiredoxin 6) was identified as a key target of miR-371-3p in establishing drug tolerance by regulating PLA2/PKCα activity and reactive oxygen species. PRDX6 expression is associated with poor prognosis in cancers of multiple tissue origins. These findings implicate miR-371-3p as a suppressor of PRDX6 and suggest that co-targeting of PRDX6 or modulating miR-371-3p expression together with targeted cancer therapies may delay or prevent acquired drug resistance. PC9 stable cell lines expressing GFP vector or miR-371-3p were generated to study the effect of miR-371-3p in response to erlotinib treatment for RNA extraction and hybridization on Affymetrix microarrays. Stable cell lines were treated with DMSO or erlotinib for 24hrs and RNA isolated for analyzing the effect of miR-371-3p on gene expression upon erlotinib treatment.
Project description:Targeted therapies against EGFR show clinical benefit, but resistance to these agents invariably develops. Thus, there is a need for dynamic biomarkers - effect sensors - that reflect treatment with EGFR therapeutics during therapy. Making use of SILAC-labeling we aimed to discover plasma membrane proteins that become differentially expressed after treatment with EGFR inhibitor erlotinib in three erlotinib-sensitive breast cancer cell lines.
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:The non-small cell lung cancer (NSCLC) cell line HCC827 harbors an activating EGFR mutation (exon 19 deletion) that confers sensitivity to the FDA-approved EGFR inhibitor erlotinib. By applying the ClonTracer barcoding system, we were able to show the presence of pre-existing sub-populations in HCC827 that contribute to erlotinib resistance. Prior studies implicated that MET amplification confers resistance to erlotinib in this cell line. Therefore we examined the effects of the c-Met inhibitor crizotinib on the barcoded HCC827 population when treated either sequentially or simultaneously with both inhibitors. Despite the significant reduction in barcode complexity, the erlotinib/crizotinib combination treatment failed to eradicate all of the resistant clones implying the presence of an erlotinib/crizotinib dual resistant subpopulation. We performed transcriptome profiling (RNA-seq) to elucidate the potential resistance mechanisms of the dual resistant subpopulation in comparison to vehicle-treated or single agent erlotinib-resistant HCC827 cell populations as controls. mRNA profiling of the subpopulations of human NSCLC cell line HCC827 that contribute to EGFR inhibitor erlotinib and MET inhibitor crizotinib resistance
Project description:Chronic inflammation plays a significant role in tumor promotion, migration and invasion. Using microarray analysis, we observed a profound increase in genes involved in pro-inflammatory pathways in epidermal growth factor receptor inhibitor (EGFRI)-treated head and neck squamous cell carcinoma (HNSCC) cell lines compared to their respective vehicle-treated cell lines. We hypothesized that the efficacy of EGFRIs may be offset by the pro-inflammatory response that these drugs produce in HNSCC tumor cells. We found that clinical EGFRIs such as erlotinib, cetuximab, lapatinib and panitumumab induced the secretion of pro-inflammatory cytokines such as IL-2, IL-4, IL-6, IL-8, GM-CSF, TNFα and IFNγ. Focusing on IL-6, we found that erlotinib induced a time-dependent increase in IL-6 mRNA and protein expression and exogenous IL-6 was able to protect HNSCC cells from erlotinib-induced cytotoxicity. Conversely, an IL-6 receptor antagonist tocilizumab, sensitized HNSCC cells to erlotinib in vitro and in vivo. Inhibitors of NFκB, p38 and JNK suppressed erlotinib-induced IL-6 expression, suggesting an important role of NFκB and MAPK pathways in IL-6 expression. Furthermore, knockdown of NADPH oxidase 4 (NOX4) suppressed erlotinib-induced pro-inflammatory cytokines expression. Taken together, these results suggest that clinical EGFRIs induce the expression of pro-inflammatory cytokines via NOX4. Therefore, the anti-tumor activity of EGFRIs may be partially reduced by activation of NOX4-mediated pro-inflammatory pathways in HNSCC. Total RNA was isolated from Head and Neck Squamous Cell Carcinoma cell lines FADU, SQ20B and Cal 27 subjected to 48 hours of 0.01% DMSO or 5uM EGFR inhibitor, erlotinib treatment.
Project description:Primary murine keratinocytes were infected with Myc, MycV394D or control virus supernatants and treated with or without TGF beta 1 for 12 hours. MycV394D is a Myc mutant, which does not bind Miz-1 anymore but is still able to bind to E-box sequences (Mol Cell 10:509-521, 2002).
Project description:To investigate the effects of ZIKV infection or ZIKV-NS4B-transduction on the global proteome scale at early stages of hNPC differentiation into neurons, hNPC cells were infected with ZIKV (Asian strain: H/PF/2013; MOI=0.01) or transduced with ZIKV-NS4B or HCV-NS4B and one day later cells were either left under proliferative conditions or neuronal differentiation was induced with ROCK inhibitors treatment and growth factors withdrawals. Five days later samples were harvested and processed for quantitative label-free proteomics.