Project description:Potential vorinostat-resistance candidate genes were identified using RNA interference screening in vorinostat-resistant HCT116 cells (HCT116-VR) using a synthetic lethal approach. In order to understand the mechanisms by which these genes contributed to vorinostat response, transcriptomic analysis was conducted on HCT116-VR cells and those with siRNA-mediated knockdown of each of the vorinostat resistance candidate genes.
Project description:Potential vorinostat-resistance candidate genes were identified using RNA interference screening in vorinostat-resistant HCT116 cells (HCT116-VR) using a synthetic lethal approach. In order to understand the mechanisms by which these genes contributed to vorinostat response, transcriptomic analysis was conducted on HCT116-VR cells and those with siRNA-mediated knockdown of each of the vorinostat resistance candidate genes. There are 45 samples in total, from triplicate independent biological experiments of 15 samples each. The negative control to which all gene knockdowns are compared is the mock transfection control (mock).
Project description:Transcriptome analysis was conducted on vorinostat resistant HCT116 cells (HCT116-VR) upon knockdown of potential vorinostat resistance candidate genes in the presence and absence of vorinostat. Potential vorinostat resistance candidate genes chosen for this study were GLI1 and PSMD13, which were identified through a genome-wide synthetic lethal RNA interference screen. To understand the transcriptional events underpinning the effect of GLI1 and PSMD13 knockdown (sensitisation to vorinostat-induced apoptosis), cells were first subjected to gene knockdown, then to treatment with vorinsotat or the solvent control. Two timepoints for drug treatment were assessed: a timepoint before induction of apoptosis (4hrs for siGLI1 and 8hrs for siPSMD13) and a timepoint when apoptosis could be detected (8hrs for siGLI1 and 12hrs for siPSMD13). There are 42 samples in total, from triplicate independent biological experiments of 14 samples each.
Project description:Transcriptome analysis was conducted on vorinostat resistant HCT116 cells (HCT116-VR) upon knockdown of potential vorinostat resistance candidate genes in the presence and absence of vorinostat. Potential vorinostat resistance candidate genes chosen for this study were GLI1 and PSMD13, which were identified through a genome-wide synthetic lethal RNA interference screen. To understand the transcriptional events underpinning the effect of GLI1 and PSMD13 knockdown (sensitisation to vorinostat-induced apoptosis), cells were first subjected to gene knockdown, then to treatment with vorinsotat or the solvent control. Two timepoints for drug treatment were assessed: a timepoint before induction of apoptosis (4hrs for siGLI1 and 8hrs for siPSMD13) and a timepoint when apoptosis could be detected (8hrs for siGLI1 and 12hrs for siPSMD13).
Project description:RNA-seq analysis of vorinostat-resistant HCT116 cells following gene knockdown of GLI1 or PSMD13 with or without vorinostat treatment
Project description:Epigenetic modifying enzymes are commonly mutated in diffuse large B cell lymphoma (DLBCL). Importantly, genetics abnormalities lead to inactivation of HAT, which tilt the balance in favor of decreased protein acetylation in DLBCL cells. This suggests that protein acetylation regulation is an important factor in DLBCL pathogenesis and a potential target for therapy. We developed resistant cell lines to the histone deacetylase inhibitor (HDACi) vorinostat, in order to better define molecular mechanisms of action of HDACi in lymphoma cells. We found that cells resistant to HDACi have increased protein synthesis and proteasomal degradation. Additionally, cells resistant to HDACi have acquired increased susceptibility to proteasome inhibitors and this correlates with activation of the unfolded protein response. Importantly, using transcriptional signatures found in our resistant lymphoma cell line model, we show that tumors from DLBCL patients treated but unresponsive to HDACi therapy undergo similar changes. Together, these data show, for the first time, that HDACi may be used to prime DLBCL for targeted therapy including proteasome inhibitors. Gene expression in U937 cells after 12h exposure to 2µM vorinostat and after development of resistance to 2 µM vorinostat, with and without vorinostat in the media.
Project description:Oxaliplatin as a first-line drug frequently causes the chemo-resistance on colorectal cancer (CRC). N6-methyladenosine (m6A) methylation has been largely acknowledged in multiple biological functions. However, the molecular mechanisms underlying the m6A methylation in modulating anticancer drug resistance in CRC are still obscure. In present study, RIP-seq was conducted to investigate the occupancy of N6-methyladenosine RNA binding protein 3 (YTHDF3) served as “readers” that can recognize m6A modification site in HCT116 cells with oxaliplatin resistance (HCT116R). Then, YTHDF3 was knockdown by siRNA in HCT116 cells with oxaliplatin resistance, and RIP-seq was further conducted to investigate m6A methylation of HCT116, HCT116R and HCT116R cells with YTHDF3 knockdown.
Project description:The second leading cause of cancer death for women in the U.S. is breast cancer. Moreover, a significant number of patients with breast tumors acquire resistance to drugs during therapy. To develop targeted therapeutic strategies to combat drug resistance it is essential to understand the basic molecular mechanisms through which cancer cells control sensitivity to chemotherapeutics. To identify new candidate genes and facilitate the discovery of novel drug resistance pathways, we have generated a resistance profile or ?resistome? of etoposide resistant MCF7 breast cancer cells. Differential expression of over 5000 genes (fold change > 2, P value < 0.05) indicate that several drug resistance mechanisms may be operating in these cells, including up-regulation of ABC transporter genes, down-regulation of the drug target and down-regulation of apoptotic genes. Several transcription factors such as RUNX2, SOX9, ETS1 and SMAD3 were up-regulated in the drug resistant cells. Targeted RUNX2 knockdown in the resistant cells using siRNA increased sensitivity to etoposide and also upregulated expression of pro-apoptotic genes indicating that RUNX2 could be a molecular target against etoposide resistance. Differential miRNA (microRNA) expression was observed among the drug resistant and sensitive cells suggesting that miRNA may also play a role in regulation of drug resistance. Hsa-miR-218, which targets ABCC6, was down-regulated in the drug resistant cell line. Transfection of a miR-218 mimic could down-regulate the expression of the efflux pump ABCC6 by 65% in drug resistant cells suggesting that regulation of miRNA may play an important role in etoposide resistance. long summary Refer to individual Series. This SuperSeries is composed of the following subset Series: GSE28413: Expression profile of etoposide-resistant MCF7 (MCF7VP) cells GSE28414: Expression profile of etoposide-resistant MCF7 (MCF7VP) cells with targeted RUNX2 knockdown
Project description:Inflammatory breast cancer (IBC) is a difficult-to-treat disease with poor clinical outcomes due to high risk of metastasis and resistance to treatment. We previously described a CD44+CD24-pSTAT3+ cancer cell subpopulation with stem cell-like features in breast cancer that is dependent on JAK/STAT3 signaling. Here we report that CD44+CD24- cells are the most frequent cell-type in IBC and are commonly pSTAT3+. Combination of JAK/STAT3 inhibition with paclitaxel decreased IBC xenograft growth more than either agent alone. We developed and characterized IBC cell lines resistant to paclitaxel and doxorubicin to mimic therapeutic resistance in patients. Multi-omic profiling of parental and resistant cells revealed genes associated with lineage identity and inflammation were enriched in chemotherapy resistant derivatives. Integrated pSTAT3 ChIP-seq and RNA-seq analyses showed pSTAT3 regulates genes related to inflammation and epithelial to mesenchymal transition (EMT) in resistant cells, as well as PDE4A, a cAMP-specific phosphodiesterase. Metabolomic characterization identified elevated cAMP signaling and CREB as a candidate therapeutic target in IBC. We also investigated cellular dynamics and heterogeneity at the single cell level during chemotherapy and acquired resistance by CyTOF and single cell RNA-seq. We identified mechanisms of resistance including a shift from luminal to basal/mesenchymal cell states through selection for rare pre-existing subpopulations or an acquired change. Lastly, we showed that combination treatment with paclitaxel and JAK/STAT3 inhibition prevented the emergence of this more mesenchymal chemo-resistant subpopulation. Our results provide mechanistic rational for combination of chemotherapy with inhibition of JAK/STAT3 signaling as a new more effective therapeutic strategy in IBC.