Persistent Effect of mTOR Inhibition on Preneoplastic Foci Progression and Gene Expression in a Rat Model of Hepatocellular Carcinoma
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ORGANISM(S): Rattus norvegicus
PROVIDER: GSE73039 | GEO | 2016/03/03
SECONDARY ACCESSION(S): PRJNA296009
REPOSITORIES: GEO
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Project description:We have shown previously that rapamycin, the canonical inhibitor of the mechanistic target of rapamycin (mTOR) complex 1, markedly inhibits the growth of focal lesions in the resistant hepatocyte (Solt-Farber) model of hepatocellular carcinoma (HCC) in the rat. In the present study, we characterized the proteome of persistent, pre-neoplastic focal lesions in this model. One group was administered rapamycin by subcutaneous pellet for 3 weeks following partial hepatectomy and euthanized 4 weeks after the cessation of rapamycin. A second group received placebo pellets. Results were compared to unmanipulated control animals and to animals that underwent an incomplete Solt-Farber protocol to activate hepatic progenitor cells. Regions of formalin-fixed, paraffin-embedded tissue were obtained by laser capture microdissection (LCM). Proteomic analysis yielded 11,070 unique peptides representing 2,227 proteins. Quantitation of the peptides showed increased abundance of known HCC markers (e.g., glutathione S-transferase-P, epoxide hydrolase, 6 others) and potential markers (e.g., aflatoxin aldehyde reductase, glucose 6-phosphate dehydrogenase, 10 others) in foci from placebo-treated and rapamycin-treated rats. Peptides derived from cytochrome P450 enzymes were generally reduced. Comparisons of the rapamycin samples to normal liver and to the progenitor cell model indicated that rapamycin attenuated a loss of differentiation relative to placebo. We conclude that early administration of rapamycin in the Solt-Farber model not only inhibits the growth of pre-neoplastic foci but also attenuates the loss of differentiated function. In addition, we have demonstrated that the combination of LCM and mass spectrometry-based proteomics is an effective approach to characterize focal liver lesions.
2018-10-26 | PXD005845 | Pride
Project description:Our strategy was to manipulate mTOR signaling in vivo, then characterize the transcriptome and translating mRNA in liver tissue. In adult rats, we used the non-proliferative growth model of refeeding after a period of fasting, and the proliferative model of liver regeneration following partial hepatectomy. We also studied livers from pre-term fetal rats (embryonic day 19-20) in which fetal hepatocytes are asynchronously proliferating. All three models employed rapamycin to inhibit mTOR signaling.
2015-06-01 | GSE67022 | GEO
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).
2013-02-08 | E-GEOD-19885 | biostudies-arrayexpress
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.
2013-02-08 | GSE19916 | GEO
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.
2013-02-08 | GSE19885 | GEO
Project description:The mechanistic target of rapamycin (mTOR) is a central regulator of cell growth and an attractive anti-cancer target that integrates diverse signals to control cell proliferation. Previous studies using mTOR inhibitors have shown that mTOR targeting suppresses gene expression and cell proliferation. To date, however, mTOR targeted therapies in cancer have seen very limited efficacy, and one key issue is related to the development of evasive resistance. In this manuscript, through the use of a gene targeting mouse model, we have found that inducible deletion of mTOR in hematopoietic stem cells (HSCs) results in a loss of quiescence and increased proliferation. Adaptive to the mTOR loss, mTOR-/- HSCs increase chromatin accessibility and activate global gene expression, contrary to the effects of short-term inhibition by mTOR inhibitors. Mechanistically, such genomic changes are due to a rewiring and adaptive activation of the ERK/MNK/eIF4E signaling pathway that enhances the protein translation of RNA polymerase II (RNAP II), which in turn leads to increased c-Myc gene expression, allowing the HSCs to thrive despite loss of a functional mTOR pathway. This adaptive mechanism can also be utilized by leukemia cells undergoing long-term mTOR inhibitor treatment to confer resistance to mTOR drug targeting. The resistance can then be counteracted by MNK, CDK9, or c-Myc inhibition. These results provide new insights into the physiological role of mTOR in mammalian stem cell regulation and implicate a novel mechanism of evasive resistance in the context of mTOR targeting.
2020-12-24 | GSE134316 | GEO
Project description:Background There is much discussion in the cancer drug development community about how to incorporate molecular tools into early-stage clinical trials to assess target modulation, measure anti-tumor activity, and enrich the clinical trial population for patients who are more likely to benefit. Small, molecularly focused clinical studies offer the promise of the early definition of optimal biologic dose and patient population. Methods and Findings Based on preclinical evidence that phosphatase and tensin homolog deleted on Chromosome 10 (PTEN) loss sensitizes tumors to the inhibition of mammalian target of rapamycin (mTOR), we conducted a proof-of-concept Phase I neoadjuvant trial of rapamycin in patients with recurrent glioblastoma, whose tumors lacked expression of the tumor suppressor PTEN. We aimed to assess the safety profile of daily rapamycin in patients with glioma, define the dose of rapamycin required for mTOR inhibition in tumor tissue, and evaluate the antiproliferative activity of rapamycin in PTEN-deficient glioblastoma. Although intratumoral rapamycin concentrations that were sufficient to inhibit mTOR in vitro were achieved in all patients, the magnitude of mTOR inhibition in tumor cells (measured by reduced ribosomal S6 protein phosphorylation) varied substantially. Tumor cell proliferation (measured by Ki-67 staining) was dramatically reduced in seven of 14 patients after 1 wk of rapamycin treatment and was associated with the magnitude of mTOR inhibition (p = 0.0047, Fisher exact test) but not the intratumoral rapamycin concentration. Tumor cells harvested from the Ki-67 nonresponders retained sensitivity to rapamycin ex vivo, indicating that clinical resistance to biochemical mTOR inhibition was not cell-intrinsic. Rapamycin treatment led to Akt activation in seven patients, presumably due to loss of negative feedback, and this activation was associated with shorter time-to-progression during post-surgical maintenance rapamycin therapy (p < 0.05, Logrank test). Conclusions Rapamycin has anticancer activity in PTEN-deficient glioblastoma and warrants further clinical study alone or in combination with PI3K pathway inhibitors. The short-term treatment endpoints used in this neoadjuvant trial design identified the importance of monitoring target inhibition and negative feedback to guide future clinical development. Keywords: Comparative Genomic Hybridization
2008-01-29 | GSE7344 | GEO
Project description:The effect of short term Rapamycin on the transcriptome of old mouse liver
| PRJNA209717 | ENA
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 was extracted from 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 quadruplicate 1)RS cells treated with DMSO for 24 h(BC3H1, reference), 2) RS cells treated for 24 h with 100 nM rapamycin (BC3H1+R), 3) RR1 cells consantly treated with 1uM Rapamycion (RR1+R). For each experiment, 1 μM of total RNA was labeled with Hy3TM dye and a reference RNA pool (consisting of a mixture of equal amounts of total RNA from BC3H1, BC3H1+R and RR1+R cells) was labeled with Hy5TM dye using the miRCURYTM Labeling Kit. The samples were hybridized to Exiqon miRCURYTM LNA Arrays (V10.0).
2013-02-08 | E-GEOD-19916 | biostudies-arrayexpress
Project description:Analysis of the effect of gene expression in the livers of old mice (25 months of age) fed rapamycin short term (6 months) Rapamycin from 19 months of age.
2014-02-07 | GSE48331 | GEO