Whole genome study of PC3, T24, H460, H4 in hypoxic and normoxic conditions under photon radiation
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ABSTRACT: In gene expression studies for hypoxic conditions in radiation, the effect of hypoxia and the effect of radiation are both well studied. The interplay of those effects is not well studied though, especially regarding the question of weather the genetic fingerprint is influenced by either one of the two condition or a combination of both. In our study, we developed a new analysis method to extract the oxygen impact on the genetic patterns and studied this new analysis method across the data of 4 cell lines.
Project description:The activation of the transcription factor Hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumor development, tumor progression and resistance to chemo- and radiotherapy. In order to identify compounds targeting the HIF pathway, a small-molecule library was screened using a luciferase-driven HIF-1 reporter cell line under hypoxia. The high throughput screen led to the identification of a class of aminoalkyl-substituted compounds that inhibited hypoxia-induced HIF-1 target gene expression in human lung cancer cell lines at low nanomolar concentrations but did not affect expression levels of genes outside of the HIF-1 pathway. Lead structure BAY 87-2243 was found to inhibit HIF-1α protein accumulation under hypoxic conditions in NSCLC cell line H460 but had no effect on HIF-1α protein accumulation and HIF target gene expression in RCC4 cells lacking VHL activity or in H460 cells after inhibition of HIF prolyl hydroxylase activity. BAY 87-2243 had no effect on HIF-α-mRNA levels. Antitumor activity of BAY 87-2243 and suppression of HIF-1 target gene expression in vivo was demonstrated in a H460 xenograft model. BAY 87-2243 did not inhibit cell proliferation under standard conditions. However under glucose depletion, a condition favoring mitochondrial ATP generation as energy source, BAY 87-2243 inhibited cell proliferation in the nanomolar range. Further experiments revealed that BAY 87-2243 inhibits mitochondrial production of reactive oxygen species (ROS) by blocking complex I activity but has no effect on complex III activity. Lowering of mitochondrial ROS production to reduce hypoxia-induced HIF-1 activity in tumors might be an interesting therapeutic approach to overcome chemo- and radiotherapy-resistance of hypoxic tumors. We used microarrays to detail the global programme of gene expression that is induced in NSCLC cell line H460 upon hypoxia (16 h incubation at 1 % pO2) and evaluated a dose-dependent effect of our HIF-1-pathway inhibitor BAY 87-2243 on genes tthat are affected by hypoxia. Specificity of BAY 87-2243 for the suppression of HIF-1-mediated gene transcription on a genome-wide scale was evaluated by microarray hybridizations using Affymetrix GeneChip Human Gene 1.0 ST arrays. RNA from normoxic H460 cells and from hypoxic H460 cells incubated with 1, 10 and 100 nM BAY 87-2243 respectively was subjected to array hybridization. Of those 30 genes that were most strongly suppressed by 100 nM BAY 87-2243 in hypoxic H460 cells compared to DMSO-treated hypoxic H460 cells, virtually all of them are induced by prior hypoxia and most of these genes have been described in the literature as HIF-1 target genes
Project description:It is elusive whether clonal selection of tumor cells in response to ionizing radiation (IR) is a deterministic or stochastic process. With high resolution clonal barcoding and tracking of over 400.000 HNSCC patient-derived tumor cells the clonal dynamics of tumor cells in response to IR was analysed. Fractionated IR induced a strong selective pressure for clonal reduction. This significantly exceeded uniform clonal survival probabilities indicative for a strong clone-to clone difference. within tumor cells. Survival to IR is driven by a deterministic clonal selection of a smaller population which commonly survives radiation, while increased clonogenic capacity is a result of clonal competition of cells which have been selected stochastically. The ratio of these parameters is amenable to radiation sensitivity which correlates to prognostic biomarkers of HNSCC. Evidence for the existence of a rare subpopulation with an intrinsically radiation resistant phenotype was found at a frequency of 0.6-3.3%. With cellular barcoding we introduce a novel functional heterogeneity associated qualitative readout for evaluating the contribution of stochastic and deterministic clonal selection processes in response to IR. To analyze transcriptomic changes of HNSCC cell lines after fractionated Photon IR (5x4Gy), RNAseq analysis was performed on irradiated cells in comparison to untreated control cells (EBI submission E-MTAB-9693)
Project description:In the current global scenario there is always a possibility that a terrorist group might acquire material to produce a nuclear device. In the likelihood of a detonation of an improvised nuclear device (IND) the prompt radiation would consist of both photons (gamma rays) and neutrons. As neutrons generally have a high Relative Biological Effectiveness (RBE) for most physiological endpoints, it is important to understand the impact that neutrons would have on the biodosimetry methods that are being developed for medical triage purposes. We have previously reported transcriptomic response in human and mouse blood to neutron exposure and determined its RBE compared to photons for gene induction. In this report, we studied the effect of mixed neutron-photon radiation on gene expression in human peripheral blood in order to mimic an IND type radiation observed increase in number as well as expression level of genes with increasing percentage of neutron in mixed exposures which peaked at 25% neutron exposure which was maximum neutron percentage used for the study. We identified 156 genes that responded significantly to all the neutron-photon mixed exposures. These genes were found to be mainly involved in p53 signaling and DNA damage response. The 25% neutron exposure also showed maximum enrichment of known neutron associated gene ontology terms reported in the previous studies. Analysis of upstream regulators of gene expression showed strong activation of TP53, SLC29A1, PDCD1 and suppression of ANLN, AURK and ANXA2 across all exposures. While AGT was exclusively activated by neutron specific exposures. We confirmed the expression of genes which showed increased expression as a function of increased neutron percentage using quantitative real-time RT-PCR which matched with the microarray data. Thus, the data in this current study clearly indicates that gene expression can be used to estimate the percentage of the neutron component in mixed neutron-photon exposures.
Project description:The time factor in the development of radiation induced lung fibrosis is important but not well characterized so far. This study was to investigate the time series of acute-, subacute-, early and late- timepoints after exposure with low-LET photons versus proton versus and high-LET carbon-ions. The role of CTGF inhibitor in modulating inflammation related signaling pathways were also studied at the acute timepoints. The potential mechanisms underlining the time-dependent progression of inflammatory and fibrotic response is to be illustrated in the present study.
Project description:Combination of platinum-based chemotherapy and radiation is currently the standard treatment for locally advanced lung cancer patients. However, therapeutic resistance to these therapies may arise from the presence of cancer stem cells (CSCs). To investigate the CSCs hypothesis of chemo-radiation resistance, we used microarray assay to profile CSCs-like cisplatin-resistant lung cancer cells (CDDP-R) versus its parental cells. CDDP-R cells were established by exposing H460 lung cancer cells to 3µM cisplatin for 7 days, followed by 0.8% methylcellulose selection over 14 consecutive days. We found that CDDP-R cells expressed higher levels of stem cell markers, including CD133 and ALDH. They are more resistant to cisplatin- and etoposide-induced apoptosis and to high radiation dose (20Gy). Clonogenic assays suggest that CDDP-R cells were more resistant to radiation than parental H460 cells (DER=1.21, p<0.01). Xenograft studies suggest that CDDP-R cells were more tumorigenic (p<0.001). Microarray and comprehensive protein interaction networks analyses revealed IGFBP3 as a highly ranked hub protein which plays an important role in the mechanism of cisplatin resistance. We found reduced level of IGFBP3 and enhanced IGFR-1 activation upon IGF stimulation in CDDP-R cells. The specific targeting of IGF-1R using siRNA resulted in significant sensitization of CDDP-cells (DER=1.17, p<0.05) to radiation compared with the parental H460 cells. Our findings suggest that CDDP-R cells have the characteristics of CSCs and constitute a “suitable” model to study lung CSCs. Profiling of CSCs-like H460 cells led to the identification of IGF as an important pathway for chemo- and radiotherapy resistance in lung cancer. gene expression comparison of two groups
Project description:Germline and somatic mutations in BRCA1predispose to breast cancer. We found that proteasome inhibitors can selectively kill BRCA1-depleted cells. The toxic response involves a deregulation of the G1/S cell cycle checkpoint via hyperphosphorylation of RB1, 53BP1-mediated arrest at G2/M checkpoint, and ERN1-mediated unfolded protein response, culminating in a TNF receptor-mediated apoptosis. The study new unexpected molecular functions for BRCA1 protein and opens a novel possibility for the treatment of BRCA1-deficient cancers. We used microarrays to detail the global programme of gene expression underlying the response of BRCA1-deficient cells to proteasome inhibitor bortezomib. We aimed to identify genes that are strongly up- or down-regulated with a combination of BRCA1 knockdown and proteasome inhibition, but none of these treatments alone before the onset of apoptosis. HeLa and U2OS cells were transfected either with a non-targeting or anti-BRCA1 siRNAs (siControl or siBRCA1, respectively), treated with bortezomib for 8 hours, after which RNA was extracted for hybridization on Affymetrix microarray. The following treatments have been performed: (T1) siControl; (T2) siControl + 20 nM bortezomib for 8h; (T3) siBRCA1; (T4) siBRCA1 + 20 nM bortezomib for 8h. All samples were used without replicas. However, all genes showing inconsistent expression pattern between the two cell lines were excluded from further consideration. Selected candidate genes were subject to validation by qRT-PCR.
Project description:Combination of platinum-based chemotherapy and radiation is currently the standard treatment for locally advanced lung cancer patients. However, therapeutic resistance to these therapies may arise from the presence of cancer stem cells (CSCs). To investigate the CSCs hypothesis of chemo-radiation resistance, we used microarray assay to profile CSCs-like cisplatin-resistant lung cancer cells (CDDP-R) versus its parental cells. CDDP-R cells were established by exposing H460 lung cancer cells to 3µM cisplatin for 7 days, followed by 0.8% methylcellulose selection over 14 consecutive days. We found that CDDP-R cells expressed higher levels of stem cell markers, including CD133 and ALDH. They are more resistant to cisplatin- and etoposide-induced apoptosis and to high radiation dose (20Gy). Clonogenic assays suggest that CDDP-R cells were more resistant to radiation than parental H460 cells (DER=1.21, p<0.01). Xenograft studies suggest that CDDP-R cells were more tumorigenic (p<0.001). Microarray and comprehensive protein interaction networks analyses revealed IGFBP3 as a highly ranked hub protein which plays an important role in the mechanism of cisplatin resistance. We found reduced level of IGFBP3 and enhanced IGFR-1 activation upon IGF stimulation in CDDP-R cells. The specific targeting of IGF-1R using siRNA resulted in significant sensitization of CDDP-cells (DER=1.17, p<0.05) to radiation compared with the parental H460 cells. Our findings suggest that CDDP-R cells have the characteristics of CSCs and constitute a “suitable” model to study lung CSCs. Profiling of CSCs-like H460 cells led to the identification of IGF as an important pathway for chemo- and radiotherapy resistance in lung cancer.
Project description:In this study, we explored the mechanisms of hypoxia-induced EGFR TKI resistance in non-small cell lung cancer (NSCLC) harbored activating EGFR mutation. The NSCLC cell lines were exposed to normorxia or 1% oxygen for 4 weeks, and then we tested EGFR TKI sensitivity in normoxic and hypoxic NSCLC cell lines. In this microarray experiment, we used normoxic HCC827 and hypoxia-induced gefitinib resistant clones, C2-3 and C2-10. Those clones were selected with gefitinib treatment after the HCC827 were exposed to 1% oxygen for 4 weeks, and the HCC827 C2-3 and C2-10 clones were selected at random for this study.
Project description:In the present study approximately 1 to 2 mm3 prostate tumor AT1 was inoculated subcutaneously in the right hind leg of adult male Copenhagen rats. When the tumor diameter exceeded 15 mm, tumors of 5 and 4 rats were irradiated with carbon ion radiation of 37 or 16Gy respectively. Tumors of 5 other rats were irradiated with photon radiation of 37Gy. One animal irradiated with 37 Gy carbon ion radiation and one animal irradiated with photon radiation was sacrificed 12h, 30h, 72h, 7d and 14d after irradiation respectively. One animal irradiated with 16 Gy photon radiation was sacrificed 12h, 60h, 7d and 14d after irradiation respectively. Non-irradiated animals were sacrificed at 60h time point. Tumors were dissected and frozen in liquid nitrogen immediately. Total RNA from tumor material was isolated using the NucleoSpin RNA L kit (#740962.20, Macherey-Nagel). Differential gene expression analysis was performed on the Agilent whole rat genome Oligo Microarray (44k) platform by comparative two dye hybridisation with dye-swaps.
Project description:To identify a set of genes related to radioresistance, we analyzed the time-series gene expression profiles of radioresistant H1299 and radiosensitive H460 lung cancer cells in response to 2 Gy of ionizing radiation (IR) by performing quadratic regression (QR) analysis. Out of the 21,331 genes, we selected 6,538 genes by QR analysis from the gene expression profile of H460 cells and 6,086 genes from that of H1299 cells. Most of the genes identified in the H460 cells were classified into continuously up- or down-regulated groups, while the major QR groups were transiently changed groups in the H1299 cell line. From gene ontology analysis of the major QR groups, the DNA damage response was commonly enriched in both cell lines. DNA repair-related genes such as ATM, ATR, TP53BP1, BRCA1, MRE11, NBN and RAD50 were particularly up-regulated in H1299 cells. Suppression of these DNA repair-related genes using siRNA made H1299 cells radiosensitive to ionizing radiation. The data suggest that differential responses to DNA damage confer radioresistance to cancer cells, and provide potential novel targets for sensitizing radiotherapy.