Gene expression analysis of breast tumours from dormant and acquired resistant patients
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ABSTRACT:
PROVIDER: PRJNA437443 | ENA |
REPOSITORIES: ENA
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Project description:Sequential patient-matched samples treated with extended neoadjuvant therapy were studied. Long-term treatment (letrozole) induced changes in dormant and resistant patients were determined. Samples were classified as pre-treatment (timepoint1, <0 days), early-on treatment (timepoint2, 0-120 days) and long-term treatment (timepoint4, >120 days).
2019-01-05 | GSE111563 | GEO
Project description:Anti-EGFR antibodies are effective in therapies for late-stage colorectal cancer (CRC); however, many tumours are unresponsive or develop resistance. We performed genomic analysis of intrinsic and acquired resistance to anti-EGFR therapy in prospectively collected tumour samples from 25 CRC patients receiving cetuximab (an EGFR inhibitor). Of 25 CRC patients, 13 displayed intrinsic resistance to cetuximab; 12 were intrinsically sensitive. We obtained six re-biopsy samples at acquired resistance from the intrinsically sensitive patients. NCOA4–RET and LMNA–NTRK1 fusions and NRG1 and GNAS amplifications were found in intrinsic-resistant patients. In cetuximab-sensitive patients, we found KRAS K117N and A146T mutations in addition to BRAF V600E, AKT1 E17K, PIK3CA E542K, and FGFR1 or ERBB2 amplifications. The comparison between baseline and acquired-resistant tumours revealed an extreme shift in variant allele frequency of somatic variants, suggesting that cetuximab exposure dramatically selected for rare resistant subclones that were initially undetectable. There was also an increase in epithelial-to-mesenchymal transition at acquired resistance, with a reduction in the immune infiltrate. Furthermore, characterization of an acquired-resistant, patient-derived cell line showed that PI3K/mTOR inhibition could rescue cetuximab resistance. Thus, we uncovered novel genomic alterations that elucidate the mechanisms of sensitivity and resistance to anti-EGFR therapy in metastatic CRC patients.
2019-09-21 | E-MTAB-8340 | biostudies-arrayexpress
Project description:Glioblastoma (GBM) is among the most aggressive cancers. Despite aggressive radiotherapy and treatment with the alkylating agent temozolomide (TMZ), patients ultimately succumb to the disease. Although much interest has focused on highly tumorigenic GBM stem cells (GSCs), adaption of a concept from microbial research proposes that a minor population of dormant âpersisterâ cells in cancer evade current therapies. To separate dormant and treatment-resistant tumor cells in human GBM tumorspheres, we have refined density gradient protocols previously used for separation of neurosphere-forming neural stem cells (NSCs). We find that a minor cell population in human GBM tumorsphere cultures and patient-derived tumor biopsies display increased cell density. These high-density GBM cells (HDGCs) display dormancy, variable expression of proposed GSC markers, and 10-100 fold higher levels of reprogramming gene expression compared to low-density GBM cells (LDGCs). Transcriptional profiling data confirmed the slow-cycling state of HDGCs. As a result, HDGCs show decreased tumorsphere formation capacity in vitro and reduced tumorigenicity in vivo. Using tumorspheres and xenografts, we demonstrated that HDGCs show increased treatment-resistance to ionizing radiation (IR) and temozolomide treatment compared to LDGCs. Similar to the NSC lineage, our data suggest that dormant HDGCs become increasingly sensitive to anti-proliferative therapies as they become activated and further differentiate. In conclusion, density gradients represents a marker-independent approach to separate dormant and treatment-resistant tumor cells in human GBMs and other solid cancers. 12 samples, no replicates, derived from 5 individual patients
2016-07-01 | E-GEOD-71116 | biostudies-arrayexpress
Project description:Glioblastoma (GBM) is among the most aggressive cancers. Despite aggressive radiotherapy and treatment with the alkylating agent temozolomide (TMZ), patients ultimately succumb to the disease. Although much interest has focused on highly tumorigenic GBM stem cells (GSCs), adaption of a concept from microbial research proposes that a minor population of dormant “persister” cells in cancer evade current therapies. To separate dormant and treatment-resistant tumor cells in human GBM tumorspheres, we have refined density gradient protocols previously used for separation of neurosphere-forming neural stem cells (NSCs). We find that a minor cell population in human GBM tumorsphere cultures and patient-derived tumor biopsies display increased cell density. These high-density GBM cells (HDGCs) display dormancy, variable expression of proposed GSC markers, and 10-100 fold higher levels of reprogramming gene expression compared to low-density GBM cells (LDGCs). Transcriptional profiling data confirmed the slow-cycling state of HDGCs. As a result, HDGCs show decreased tumorsphere formation capacity in vitro and reduced tumorigenicity in vivo. Using tumorspheres and xenografts, we demonstrated that HDGCs show increased treatment-resistance to ionizing radiation (IR) and temozolomide treatment compared to LDGCs. Similar to the NSC lineage, our data suggest that dormant HDGCs become increasingly sensitive to anti-proliferative therapies as they become activated and further differentiate. In conclusion, density gradients represents a marker-independent approach to separate dormant and treatment-resistant tumor cells in human GBMs and other solid cancers.
2016-07-01 | GSE71116 | GEO
Project description:The acquired resistance that tumors develop during the treatment is still a central cause of cancer-associated deaths. Our study investigates the transcription changes modulated by EVs from tamoxifen- and doxorubicin-resistant breast cancer cells in sensitive cells and how these changes may induce acquired drug resistance, inhibit apoptosis, and increase survivability in the sensitive cells.
2024-11-06 | GSE273705 | GEO
Project description:BACKGROUND:The risk of recurrence for endocrine-treated breast cancer patients persists for many years or even decades following surgery and apparently successful adjuvant therapy. This period of dormancy and acquired resistance is inherently difficult to investigate; previous efforts have been limited to in-vitro or in-vivo approaches. In this study, sequential tumour samples from patients receiving extended neoadjuvant aromatase inhibitor therapy were characterised as a novel clinical model. METHODS:Consecutive tumour samples from 62 patients undergoing extended (4-45?months) neoadjuvant aromatase inhibitor therapy with letrozole were subjected to transcriptomic and proteomic analysis, representing before (??0), early (13-120?days), and long-term (>?120?days) neoadjuvant aromatase inhibitor therapy with letrozole. Patients with at least a 40% initial reduction in tumour size by 4?months of treatment were included. Of these, 42 patients with no subsequent progression were classified as "dormant", and the remaining 20 patients as "acquired resistant". RESULTS:Changes in gene expression in dormant tumours begin early and become more pronounced at later time points. Therapy-induced changes in resistant tumours were common features of treatment, rather than being specific to the resistant phenotype. Comparative analysis of long-term treated dormant and resistant tumours highlighted changes in epigenetics pathways including DNA methylation and histone acetylation. The DNA methylation marks 5-methylcytosine and 5-hydroxymethylcytosine were significantly reduced in resistant tumours compared with dormant tissues after extended letrozole treatment. CONCLUSIONS:This is the first patient-matched gene expression study investigating long-term aromatase inhibitor-induced dormancy and acquired resistance in breast cancer. Dormant tumours continue to change during treatment whereas acquired resistant tumours more closely resemble their diagnostic samples. Global loss of DNA methylation was observed in resistant tumours under extended treatment. Epigenetic alterations may lead to escape from dormancy and drive acquired resistance in a subset of patients, supporting a potential role for therapy targeted at these epigenetic alterations in the management of resistance to oestrogen deprivation therapy.
| S-EPMC6323855 | biostudies-literature
Project description:Cellular dormancy and heterogeneous cell cycle lengths provide important explanations for treatment failure following adjuvant therapy with S-phase cytotoxics in colorectal cancer (CRC) yet the molecular control of the dormant versus cycling state remains unknown. In CRCs dormant cells are found to be highly clonogenic and resistant to chemotherapies. We sought to understand the molecular features of dormant CRC cells to facilitate rationale identification of compounds to target both dormant and cycling tumour cells.
2018-05-21 | GSE114012 | GEO
Project description:Conidia of Aspergillus niger are characterized by a dormant state and are moderate stress-resistant. Upon contact with a moist substrate, germination of conidia occurs by changing from a dormant stabilized state towards a growing vegetative cell. The RNA expression levels of dormant conidia and conidia that were in various stages of germination were studied. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. This indicates that the distinct morphological changes that occur during germination are not correlated with the highest change in the transcriptome. Samples of germinating conidia of Aspergillus niger N402 were taken in triple at 0h (dormant), 2h, 4h, 6h and 8h after inoculation in CM.
2012-03-13 | E-GEOD-36439 | biostudies-arrayexpress
Project description:Conidia of Aspergillus niger are characterized by a dormant state and are moderate stress-resistant. Upon contact with a moist substrate, germination of conidia occurs by changing from a dormant stabilized state towards a growing vegetative cell. The RNA expression levels of dormant conidia and conidia that were in various stages of germination were studied. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. This indicates that the distinct morphological changes that occur during germination are not correlated with the highest change in the transcriptome.
2012-03-13 | GSE36439 | GEO
Project description:In order to establish a profile of gene expression of tumours treated with sunitinib, 4T1 breast tumours were allowed to establish in Balb/C mice for 1 week. The mice were then treated with 40 mg/kg Sunitinib in PBS and 3.72% DMSO (treatemt group) or PBS-DMSO vehicle alone (no treatment group), daily for the period of the experiment, after which the tumours were resected homogenised and subjected to CD31 microbead separation of endothelial cells and bulk tissue, both of which were subjected to agilent microarray analysis. Treated tumours greater than 250 mm3 (by caliper measurement) after 8 days of treatment were considered resistant to treatment, those smaller than this were considered sensitive to sunitinib treatment.
2016-07-06 | GSE84048 | GEO