Project description:These data provide scientific information to understand the mechanism of action of lapatinib resistance in HER2-positive patients and to test the combination of HER2-targeted agents and GSK1363089 (foretinib) in the clinic by using an acquired lapatinib-resistant cell line. Cell lines (BT474, an HER2-positive and lapatinib-sensitive cell line; BT474-J4, an acquired lapatinib-resistant cell line) were treated with lapatinib alone (1uM), foretinib (GSK1363089) alone (0.1 uM), a combination of lapatinib (1 uM) and foretinib (0.1 uM), or DMSO control for 24 hours. Triplicates were performed.
Project description:Drug-induced cardiotoxicity is a widespread clinical issue affecting numerous drug classes and remains difficult to treat. One such drug class is Tyrosine Kinase Inhibitors (TKIs), which cause varying degrees of contraction-related cardiotoxicity usually after weeks of exposure. Understanding molecular mechanisms underlying both acute and chronic toxicity of TKIs could help identify new treatment opportunities. Here, we presented transcriptome responses to four TKIs (Sunitinib, Sorafenib, Lapatinib and Erlotinib) across 3 doses and 4 time points in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Gene expression evolved continually under drug treatment and revealed changes in several biological networks that were associated with cardiac metabolism and contraction. These changes were confirmed by proteomics and resulted in metabolic and structural remodeling of hiPSC-CMs. One of the metabolic remodeling was the increased aerobic glycolysis induced by Sorafenib, which is an adaptive response in preserving cell survival under Sorafenib treatment. Drug adaptation in cardiac cells may represent new targets for managing chronic forms of TKI-induced cardiotoxicity.
Project description:Ablation of ERRalpha significantly delays ERBB2-induced mammary tumorigenesis and ERRalpha regulates genes of the ERBB2 amplicon. To further investigate the relationship between ERRalpha activity and RTK signaling, we mapped ERRalpha binding sites in SKBr3 cells upon EGF treatment or heregulin treatment. Inhibition of ERBB2 signaling using the RTK inhibitor lapatinib impacts on ERRalpha stability, while cells resistant to lapatinib treatment exhibit restored ERRalpha expression. We therefore mapped ERRalpha binding sites in parental (sensitive) cells (pSKBr3) as well as in lapatinib-resistant cells (LRSKBr3). ChIP-Seq analysis of ERRalpha binding profile in SKBr3 or BT-474 breast cancer cells.
Project description:Acquired drug resistance prevents targeted cancer therapy from achieving stable and complete responses. Emerging evidence implicates a key role for nonmutational mechanisms including changes in cell state during early stages of acquired drug resistance. Targeting nonmutational resistance may therefore present a therapeutic opportunity to eliminate residual surviving tumor cells and impede relapse. A variety of cancer cell lines harbor quiescent, reversibly drug-tolerant âpersisterâ cells which survive cytotoxic drugs including targeted therapies and chemotherapies. These persister cells survive drug through nonmutational mechanisms which are poorly understood. Specifically targeting persister cells is a promising strategy to prevent tumor relapse. We sought to identify therapeutically exploitable vulnerabilities in persister cells using the HER2-amplified breast cancer line BT474 as an experimental model. Similar to other persister cell models, upon treatment with the HER2 inhibitor lapatinib (2uM concentration) for nine or more days, the majority of BT474 cells die, revealing a small population of quiescent surviving persister cells. Removal of lapatinib allows the persister cells to regrow and to re-acquire sensitivity to lapatinib. Subsequent lapatinib treatment re-derives persister cells. The reversibility of persister cell drug resistance indicates a nonmutational resistance mechanism. Here we provide RNAseq gene expression profiling data generated from parental BT474 cells compared to BT474 persister cells generated from nine days of treatment with 2 uM lapatinib. These data can be used to identify genes and pathways which are upregulated in persister cells, revealing potential therapeutic targets. 3 biological replicates of BT474 persister cells, two biological replicates of BT474 parental cells
Project description:Fifty percent of cutaneous melanomas are driven by activated BRAFV600E, but tumors treated with RAF inhibitors, even when they respond dramatically, rapidly adapt and develop resistance. Thus, there is a pressing need to identify the major mechanisms of intrinsic and adaptive resistance and develop drug combinations that target these resistance mechanisms. In a combinatorial drug screen on a panel of 12 treatment-naïve BRAFV600E mutant melanoma cell lines of varying levels of resistance to MAPK pathway inhibition we identified the combination PLX4720, a targeted inhibitor of mutated BRaf, and lapatinib, an inhibitor of the ERBB family of receptor tyrosine kinases, as synergistically cytotoxic in the subset of cell lines that displayed the most resistance to PLX4720. To identify potential mechanisms of resistance to PLX4720 treatment and synergy with lapatinib treatment we performed a multi-platform functional genomics analysis to profile the genome as well as the transcriptional and proteomic responses of these cell lines to treatment with PLX4720. We found modest levels of resistance correlated with the zygosity of the BRAF V600E allele and RTK mutational status. Layered over base-line resistance was substantial upregulation of many ERBB pathway genes in response to BRaf inhibition, thus generating the vulnerability to combination with lapatinib. The transcriptional responses of ERBB pathway genes are associated with a number of transcription factors, including ETS2 and its associated cofactors that represent a convergent regulatory mechanism conferring synergistic drug susceptibility in the context of diverse mutational landscapes. 12 BRAF mutant melanomas and 4 melanomas with WT BRAF were exposed plx4720 treatment to evaluate their responses after 8 hours of treatment. 5 of the 12 BRAF mutant melanomas responses were also evaluated in response to the treatment of lapatinib alone, masitinib alone, the combination of lapatinib with plx4720, or the combination of masitinib with plx4720. All samples were run in at least triplicate.
Project description:Hepcidin, a peptide hormone that decreases intestinal iron absorption and macrophage iron release, is a potential drug target for patients with iron overload syndromes because its levels are inappropriately low in these individuals. Endogenous stimulants of Hepcidin transcription include bone morphogenic protein 6 (BMP) and interleukin-6 (IL-6) via effects on Smad4 or Stat3, respectively. We conducted a small-scale chemical screen in zebrafish embryos to identify small molecules that modulate hepcidin expression. We found that treatment with the isoflavone genistein from 28−52 hours post-fertilization in zebrafish embryos enhanced Hepcidin transcript levels as assessed by whole mount in situ hybridization and quantitative realtime RT-PCR. Genistein’s stimulatory effect was conserved in human hepatocytes: genistein treatment of HepG2 cells increased both Hepcidin transcript levels and Hepcidin promoter activity. We found that genistein’s effect on Hepcidin expression did not depend on estrogen receptor signaling or increased cellular iron uptake, but was impaired by mutation of either the BMP response elements or the Stat3 binding site in the Hepcidin promoter. RNA-sequencing of transcripts from genistein-treated hepatocytes indicated that genistein upregulated 68% of the transcripts that were upregulated by BMP6, however genistein raised the levels of several transcripts involved in Stat3 signaling that were not upregulated by BMP6. Chromatin-immunoprecipitation and ELISA experiments revealed that genistein enhanced Stat3 binding to the Hepcidin promoter and increased phosphorylation of Stat3 in HepG2 cells. CONCLUSION: Genistein is the first small molecule experimental drug that stimulates Hepcidin expression in vivo and in vitro. These experiments demonstrate the feasibility of identifying and characterizing small molecules that increase Hepcidin expression. Genistein and other candidate molecules may subsequently be developed into new therapies for iron overload syndromes. RNA-seq of HepG2 cells treated with DMSO 1%, BMP6 50 ng/ml, or genistein 10 micromolar. The numbers of biological replicates were 3, 2, and 3.
Project description:Ablation of ERRalpha significantly delays ERBB2-induced mammary tumorigenesis and ERRalpha regulates genes of the ERBB2 amplicon. To further investigate the relationship between ERRalpha activity and RTK signaling, we depleted ERRalpha in SKBr3 cells upon serum starvation, EGF treatment or heregulin treatment. Inhibition of ERBB2 signaling using the RTK inhibitor lapatinib impacts on ERRalpha stability. Since we have shown that the development of lapatinib-resistance restaures the expression of ERRalpha in breast cancer cells, we performed depletion of ERRalpha in SKBr3 cells that have developped resistance to lapatinib treatment in order to identify a potential reprogramming of ERRa transcriptional activity associated to lapatinib resistance, For the study of growth factor effec on ERRalpha activity, total RNA was obtained from human SKBr3 breast cancer cells cultured in DMEM deprived of FBS (starved) for 24 hours and treated with PBS, EGF (100uM) or Heregulin (100uM) for an additional 24h. Cells were transfected with siRNA against ERRalpha or with siControl for 60 hours prior to harvesting. For the effect of ERRalpha in lapatinib resistance cells, parental SKBr3 cells (pSKBr3) and Lapatinib-resistant cells (LRSKBr3, maintained in 2uM lapatinib) were transfected with siControl (siC) or siERRalpha for 60 hours prior to harvesting and RNA extraction
Project description:Cadmium (Cd) administered to female C57BL/6 mice on gestation day 8 induces a high incidence of anterior neural tube defects (exencephaly). This adverse effect can be attenuated by maternal pretreatment with zinc (Zn). In this study we used replicated microarray analysis to investigate gene expression changes induced in the embryo 5 h after maternal Cd exposure in the absence or presence of Zn pretreatment.