Project description:mTORC1 is a conserved central controller of cell growth, which is commonly activated in hepatocellular carcinoma (HCC), driving liver tumorigenesis. In addition to its established cytoplasmic functions, mTORC1 is found in the nucleus where it regulates transcription by all three major RNA polymerases. However, precisely how mTORC1 controls gene expression remains poorly understood. Herein we show that mTORC1 interacts with the BAF SWI/SNF complex and regulates genome-wide chromatin remodeling through ARID1A. Mechanically, mTORC1 stimulates ubiquitination and proteasomal degradation of ARID1A protein through SCF ubiquitin ligase. mTORC1-ARID1A axis promotes chromatin remodeling and expression of YAP target genes, thereby enhancing oncogenic growth in vitro and in vivo. These findings reveal a novel nuclear mTORC1 function and the underlying mechanism that controls oncogenic chromatin remodeling to promote hepatocarcinogenesis.
Project description:mTORC1 is a conserved central controller of cell growth, which is commonly activated in hepatocellular carcinoma (HCC), driving liver tumorigenesis. In addition to its established cytoplasmic functions, mTORC1 is found in the nucleus where it regulates transcription by all three major RNA polymerases. However, precisely how mTORC1 controls gene expression remains poorly understood. Herein we show that mTORC1 interacts with the BAF SWI/SNF complex and regulates genome-wide chromatin remodeling through ARID1A. Mechanically, mTORC1 stimulates ubiquitination and proteasomal degradation of ARID1A protein through SCF ubiquitin ligase. mTORC1-ARID1A axis promotes chromatin remodeling and expression of YAP target genes, thereby enhancing oncogenic growth in vitro and in vivo. These findings reveal a novel nuclear mTORC1 function and the underlying mechanism that controls oncogenic chromatin remodeling to promote hepatocarcinogenesis.
Project description:Dynamic mRNA gene expression from the wildtype YSBN6 during a rapamycin treatment (rapamycin-induced downshift). Rapamycin was added to yeast cells growing exponentially on glutamine as sole nitrogen source.
Project description:Drug resistance remains a major obstacle to successful cancer treatment. Here we use a novel approach to identify rapamycin as a glucocorticoid resistance reversal agent. A database of drug-associated gene expression profiles was screened for molecules whose profile overlapped with a gene expression signature of glucocorticoid (GC) sensitivity/resistance in Acute Lymphoblastic Leukemia (ALL) cells. The screen indicated the mTOR inhibitor rapamycin profile matched the signature of GC-sensitivity. We thus tested the hypothesis that rapamycin would induce GC sensitivity in lymphoid malignancy cells, and found that it sensitized cells to glucocorticoid induced apoptosis via modulation of antiapoptotic MCL1. These data indicate that MCL1 is an important regulator of GC-induced apoptosis, and that the combination of rapamycin and glucocorticoids has potential utility in ALL. Furthermore this approach represents a novel strategy for identification of promising combination therapies for cancer. Keywords: drug treatment
Project description:The licensed drug rapamycin has potential to be repurposed for geroprotection. A key challenge is to avoid the adverse side-effects of clinical dosing regimes. Here we show a profound memory effect of brief rapamycin treatment. Brief, early adult treatment extended lifespan in Drosophila to the same degree as lifelong dosing. Lasting memory of earlier rapamycin treatment was mediated by elevated autophagy in enterocytes of the gut, accompanied by increased intestinal spermidine levels and improved structure and function of the ageing intestine. Brief elevation of autophagy itself induced a long-term increase in autophagy. In mice, short-term, 3-month treatment also induced a full memory effect, with enhanced autophagy in Paneth cells, improved Paneth cell architecture and gut barrier function at levels induced by chronic treatment, even 6 months after rapamycin was withdrawn. Past rapamycin treatment also enhanced the regenerative potential of aged intestine in intestinal organoids. Full geroprotective effects of chronic rapamycin treatment can thus be obtained with a brief pulse of the drug.
Project description:Dynamic mRNA gene expression from the wildtype YSBN6 during a rapamycin treatment (rapamycin-induced downshift). Rapamycin was added to yeast cells growing exponentially on glutamine as sole nitrogen source. A sample was taken at steady-state 10 minutes before , and then 3, 7, 10, 14, 24, 56 and 120 minutes after rapamycin treatment. Biological triplicate gene expression was measured for samples -10, 7 and 24 minutes after shift, for a total of 14 chips. Changes were generally evaluated relative to the steady-state point (-10 minutes). Biological variability can be assessed from the replicates time points. Other dynamic omics data are associated with this dataset. Consult the publication for more details.
Project description:Tomatidine, a natural steroidal alkaloid from unripe green tomatoes has been shown to exhibit many health benefits. We recently provided in vitro evidence that tomatidine reduces the infectivity of Dengue virus (DENV) and Chikungunya virus (CHIKV), two medically important arthropod-borne human infections for which no treatment options are available. The objective of this mass spectrometry analysis was to determine possible proteomic changes in the human cell line Huh7 induced by tomatidine which may be indicative of the underlying antiviral activity of tomatidine.