Gene expression profile in response to doxorubicin-rapamycin combined treatment of HER-2 overexpressing human mammary epithelial cell lines
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ABSTRACT: HER-2 positive breast cancers frequently sustain elevated AKT/mammalian target rapamycin (mTOR) signaling which has been associated with resistance to doxorubicin treatment in the clinic. In our study we investigated if the mTOR inhibitor rapamycin increased the sensitivity to doxorubicin therapy in HB4a, a luminal normal mammary cell line; C5.2, a transformed cell derived from HB4a transfected with HER-2 and SKBR3 that exhibits HER-2 amplification. Flow cytometry analysis showed that the combination treatment for 24 hours with rapamycin 20nM and doxorubicin caused accumulation of HB4a and C5.2 cells in S-G2/M. Otherwise in SKBR3 cells, we observed a relative depletion of cells in S-G2/M and concomitant accumulation in G0/G1 of 10% of the cells. The analysis of IC50 of doxorubicin alone and in combination with rapamycin indicated that the sensitivity was increased 2.37 fold in HB4a, 2.46 in C5.2 and 1.87 in SKBR3, suggesting that rapamycin might have enhanced the effects of doxorubicin. Changes in gene expression resulting from co-treatment demonstrated that functional groups of genes with roles in cell cycle, proliferation, apoptosis regulation were represented in the 3 cells analysed. Other biological functions were exclusively associated with each cell suggesting that the inhibition of mTOR activation induced by HER-2 is complex and depends on the cellular context. Five independent experiments were performed for each treatment conditions: HB4a, C5.2 and SKBR3 cell lines were treated with vehicle (DRC), 20 nM of RAPAMYCIN alone (R) and 30 nM of DOXORUBICIN alone (D). The combined treatment consisted of 20 nM of RAPAMYCIN associated with 30 nM DOXORUBICIN of (DR). Total RNA extraction and hybridization on Affymetrix microarrays.
Project description:HER-2 positive breast cancers frequently sustain elevated AKT/mammalian target rapamycin (mTOR) signaling which has been associated with resistance to doxorubicin treatment in the clinic. In our study we investigated if the mTOR inhibitor rapamycin increased the sensitivity to doxorubicin therapy in HB4a, a luminal normal mammary cell line; C5.2, a transformed cell derived from HB4a transfected with HER-2 and SKBR3 that exhibits HER-2 amplification. Flow cytometry analysis showed that the combination treatment for 24 hours with rapamycin 20nM and doxorubicin caused accumulation of HB4a and C5.2 cells in S-G2/M. Otherwise in SKBR3 cells, we observed a relative depletion of cells in S-G2/M and concomitant accumulation in G0/G1 of 10% of the cells. The analysis of IC50 of doxorubicin alone and in combination with rapamycin indicated that the sensitivity was increased 2.37 fold in HB4a, 2.46 in C5.2 and 1.87 in SKBR3, suggesting that rapamycin might have enhanced the effects of doxorubicin. Changes in gene expression resulting from co-treatment demonstrated that functional groups of genes with roles in cell cycle, proliferation, apoptosis regulation were represented in the 3 cells analysed. Other biological functions were exclusively associated with each cell suggesting that the inhibition of mTOR activation induced by HER-2 is complex and depends on the cellular context.
Project description:In SKBR3 cells, simultaneous targeting of RARM-kM-1 with all-trans retinoic acid (ATRA) and HER2 with lapatinib results in synergistic anti-tumor responses. SKBR3 cells were treated with vehicle (DMSO), lapatinib (100 nM), ATRA (100 nM) or lapatinib+ATRA for 36 hours and miRNA expression profile was determined by one-color Agilent microarray experiments.
Project description:Newly synthesized proteome analysis of EPP2 murine pancreatic cancer cells with induced knockout of tRNA wobble enzymes Elp3 or Ctu1 and mTOR inhibitor treatment. Knockouts were induced for 4 days, mTOR inhibitors were 5 h rapamycin [50 nM] or torin 1 [50 nM].
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:The mammalian target of rapamycin (mTOR) is a central regulator of cell growth and proliferation in response to growth factor and nutrient signaling. Consequently, this kinase is implicated in metabolic diseases including cancer and diabetes so there is great interest in understanding mTOR regulatory networks. mTOR exists in two functionally distinct complexes, mTORC1 and mTORC2, and whereas the natural product rapamycin only inhibits a subset of mTORC1 functions, recently developed ATP-competitive mTOR inhibitors have revealed new roles for both complexes. To examine the complete spectrum of mTOR responsive cellular processes, we compared the transcriptional profiles of mammalian cells treated with rapamycin versus the ATP-competitive inhibitor PP242. Our analysis provides a genome-wide view of the transcriptional outputs of mTOR signaling that are insensitive to rapamycin. Gene expression in mouse NIH3T3 cells was measured after 18 hour treatment with DMSO (control), 50 nM rapamycin, or 2 uM PP242. Four independent experiments were performed for each condition.
Project description:SKBR3 cells, which bear both an HER2 and a RARA gene amplification, were treated for 12 or 48 hours with 100 nM retinoic acid, 100 nM lapatinib or the combination.The two drugs synergize and induce massive apoptosis. The aim is to find the molecular mechanism(s) of this synergism. Gene expression profiling was performed using Agilent two-color 4X44K arrays. Original processed data are available in the archive: http://www.ebi.ac.uk/arrayexpress/files/E-MEXP-3192/E-MEXP-3192.additional.zip
Project description:The mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation. Inhibitors of mTOR are being evaluated as anti-tumor agents. Given the emerging role of microRNAs (miRNAs) in tumorgenesis we hypothesized that miRNAs could play important roles in the response of tumors to mTOR inhibitors. Rapamycin resistant myogenic cells developed by long-term rapamycin treatment showed extensive reprogramming of miRNAs expression, characterized by up-regulation of the mir-17~92 and related clusters and down-regulation of tumor-suppressor miRNAs. Antagonists of oncogenic miRNA families and mimics of tumor suppressor miRNAs (let-7) restored rapamycin sensitivity in resistant tumor cells. This study identified miRNAs as new downstream components of the mTOR-signaling pathway, which may determine the response of tumors to mTOR inhibitors. Total RNA extraction and hybridization on Affymetrix microarrays of rapamycin sensitive (RS) cells (BC3H1, mouse brain tumor cell line with myogenic properties, ATCC) cultured in Dulbecco’s modified essential medium (DMEM) media supplemented with 20% fetal bovine serum (FBS), penicillin (100 U/ml) and streptomycin (100 mg/ml). Rapamycin resistant cells (RR1) were developed by culturing BC3H1 cells in the presence of 1 uM rapamycin for 6 months. Three samples in triplicates: 1) Rapamycin sensitive cells treated with DMSO for 24 h(BC3H1, reference), 2) Rapamycin sensitive cells treated for 24 h with 100 nM rapamycin (BC3H1+R), 3) Rapamycin resistant cells constantly treated with 1uM Rapamycion (RR1+R).
Project description:Drug resistance in breast cancer is the major obstacle to a successful outcome following chemotherapy treatment. While upregulation of multidrug resistance (MDR) genes is a key component of drug resistance in multiple cancers, the complexity and hierarchy of non-MDR driven drug resistance pathways are still largely unknown. The aim of this study was to identify pathways contributing to anthracycline resistance using isogenic drug resistant breast cancer cell lines. We generated isogenic MDA-MB-231, MCF7, SKBR3 and ZR-75-1 epirubicin-resistant breast cancer cell lines, which were cross-resistant to doxorubicin and SN-38; the SKBR3 cell line was also resistant to taxanes. Epirubicin-resistant cells were morphologically different from native cells, and had alterations in apoptosis and cell cycle profile. Using gene expression and small-molecule inhibitor analyses we identified deregulation of histone H2A and H2B genes in all four cell lines. These genes contribute to several biological pathways, which include cell cycle, chromosomal maintenance, epigenetics, RNA and mitochondrial transcription. Histone deacetylase and cell cycle/DNA damage small molecule inhibitors reversed resistance and were cytotoxic for all four epirubicin-resistant cell lines confirming that histone and cell cycle pathways are associated with epirubicin resistance. This study has established model systems for investigating drug resistance in all four breast cancer subtypes and revealed key pathways that contribute to anthracycline resistance. The global gene expression analysis included 4 parental (anthracycline sensitive) and 4 resistant breast cancer cell lines, in biological triplicates.
Project description:ERM-NM-117p is a synthetic peptide corresponding to the sequence P295LMIKRSKKNSLALSLT311 of the estrogen receptor alpha (ERM-NM-1) and initially synthesized to mimic its calmodulin binding site. ERM-NM-117p was subsequently found to elicit estrogenic responses in E2-deprived ERM-NM-1-positive breast cancer cells, increasing proliferation and E2-dependent gene transcription. Surprisingly, in E2-supplemented media, ERM-NM-117p induced apoptosis and modified the actin network, influencing thereby cell motility. Here, we report that ERM-NM-117p induces a massive early (3h) transcriptional activity in breast cancer cell lines SKBR3). Remarkably, about 75% of the significantly modified transcripts were also modified by E2, confirming the pro-estrogenic profile of ERM-NM-117p. The different ER spectra of the used cell lines allowed us to extract a specific ERM-NM-117p signature related to ERM-NM-1 and its variant ERM-NM-136. With respect to ERM-NM-1, the peptide activates nuclear (cell cycle, cell proliferation, nucleic acid and protein synthesis) and extranuclear signaling pathways. In contrast, through ERM-NM-136 it exerts inhibitory events on inflammation and cell cycle and inhibition of EGFR signaling. This is the first work reporting ERM-NM-136 specific transcriptional effects. The fact that a number ERM-NM-117p-induced transcripts is different from those activated by E2 revealed that the apoptosis and actin modifying effects of ERM-NM-117p are independent from the ER-related actions of the peptide. Cells after a 4h incubation with medium containing 10% charcoal stripped FBS were incubated with or without E2 (10-6M) or ERa17p in RPMI 1640 supplemented with 10% charcoal stripped FBS, for 3 hours. Total RNA was isolated using Nucleospin II columns (Macheray-Nagel, Dttren, Germany), according to the manufacturerM-bM-^@M-^Ys instructions. RNA was labeled and hybridized according to the Affymetrix protocol (Affymetrix Gene-Chip Expression Analysis Technical Manual), using the HGU133A plus 2 chip, analyzing a total of 54675 transcripts. Signals were detected by an Affymetrix microarray chip reader.
Project description:Activation of the immune system is a way for host tissue to defend itself against tumor growth. Hence, treatment strategies that are based on immunomodulation are on the rise. Conventional cytostatic drugs such as the anthracycline doxorubicin can also activate immune cell functions of macrophages and natural killer cells. In addition, cytotoxicity of doxorubicin can be enhanced by combining this drug with the cytokine IFN-alpha. Although doxorubicin is one of the most applied cytostatics, the molecular mechanisms of its immunomodulation ability are not investigated thoroughly. In microarray analyses of HeLa cells, a set of 19 genes related to interferon signaling was significantly overrepresented among genes regulated by doxorubicin exposure including STAT-1, -2, IRF9, NMI, and caspase 1. Regulation of these genes by doxorubicin was verified with Real-Time PCR and immunoblotting. An enhanced secretion of IFN-alpha was observed when HeLa cells were exposed to doxorubicin as compared to untreated cells. IFN-alpha neutralizing antibodies and inhibitors of JAK-STAT signaling (ATA and AG490) significantly abolished doxorubicin-stimulated expression of interferon signaling-related genes. Furthermore, inhibition of JAK-STAT signaling significantly reduced doxorubicin induced caspase 3 activation and desensitized HeLa cells to doxorubicin cytotoxicity. In conclusion, we demonstrate that doxorubicin induces interferon-responsive genes via IFN-alpha-JAK-STAT1 signaling and that this pathway is relevant for doxorubicinM-bM-^@M-^Ys cytotoxicity in HeLa cells. As immunomodulation is a promising strategy in anticancer treatment, this novel mode of action of doxorubicin may help to further improve the use of this drug among different types of anticancer treatment strategies. One batch of HeLa Cell culture treated with doxorubicin and DMSO (control) were used for screening of global changes at the transcriptome level.