Project description:N-myc downstream-regulated gene 1 (*NDRG1*) is induced by cellular stress such as hypoxia and DNA damage, and in humans, germ line mutations cause Charcot-Marie-Tooth disease. However, the roles of NDRG1 in the cell are not fully understood. Previously, NDRG1 was shown to mediate doxorubicin resistance under hypoxia, suggesting a role for NDRG1 in cell survival under these conditions. We found decreased apoptosis in doxorubicin-treated cells expressing NDRG1 shRNAs under normoxia, demonstrating a requirement for NDRG1 in apoptosis in breast epithelial cells under normal oxygen pressure. We further compared expression profiles in human breast epithelial cells ectopically over-expressing NDRG1 with cells expressing NDRG1 shRNAs in order to identify biological pathways where NDRG1 is involved. The results suggest that NDRG1 may have roles connected to vesicle transport. The previously reported roles of NDRG1 in apoptosis, myelin sheet maintenance, enhanced exocytosis in mast cells and in cellular responses to hypoxia, heavy metals, and androgen may all converge by NDRG1 having a role linked to vesicle transport.
Project description:N-myc downstream-regulated gene 1 (*NDRG1*) is induced by cellular stress such as hypoxia and DNA damage, and in humans, germ line mutations cause Charcot-Marie-Tooth disease. However, the roles of NDRG1 in the cell are not fully understood. Previously, NDRG1 was shown to mediate doxorubicin resistance under hypoxia, suggesting a role for NDRG1 in cell survival under these conditions. We found decreased apoptosis in doxorubicin-treated cells expressing NDRG1 shRNAs under normoxia, demonstrating a requirement for NDRG1 in apoptosis in breast epithelial cells under normal oxygen pressure. We further compared expression profiles in human breast epithelial cells ectopically over-expressing NDRG1 with cells expressing NDRG1 shRNAs in order to identify biological pathways where NDRG1 is involved. The results suggest that NDRG1 may have roles connected to vesicle transport. The previously reported roles of NDRG1 in apoptosis, myelin sheet maintenance, enhanced exocytosis in mast cells and in cellular responses to hypoxia, heavy metals, and androgen may all converge by NDRG1 having a role linked to vesicle transport. SUM102 and ME16C2 stably transduced with siRNA against NDRG1 compared with empty vector control ZR-75-1 stably transduced with NDRG1 overexpression construct compared with empty vector control Two condition design
Project description:Long non-coding RNAs (lncRNAs) have been regarded to participate in multiple genetic pathways in cancer. Also, mitochondria-associated lncRNAs have been discovered to module mitochondrial function and metabolism. Previously, our lab identified oxygen responsive lncRNAs in breast cancer MCF-7 cells under normoxic, hypoxic and re-oxygenated conditions by using next generation sequencing technology. Among them, a novel mitochondrial lncRNA Mitochondrial Oxygen Responsive Transcript 1 (MTORT1) was chosen for further investigation. Therefore, the purpose of this study was to investigate the characterizations, function roles, and mechanisms of MTORT1 in breast cancer cells.
Project description:N-myc downstream regulated gene 1 (NDRG1) is a member of the NDRG family of intracellular proteins, and plays a central role in a wide range of biological processes including stress response, differentiation, and maintenance of the myelin sheath. The overexpression of NDRG1 is an indicator of poor prognosis in various pathological conditions. Here, we found that NDRG1 is an independent prognostic marker of poor outcome in breast cancer (BC). NDRG1 expression is regulated by a variety of molecular mechanisms, including transcriptional and post-translational control. In the present study, CRISPR-based inactivation of NDRG1 allowed us to demonstrate that this protein is required for breast cancer cell invasion, without affecting viability. We observed that different acute stress conditions converge on protein kinase C (PKC) activation driving enhanced NDRG1 expression through a signaling pathway that involves ROCK/AMPK/Akt kinases. This newly discovered mechanism was specific for NDRG1 as the expression of other NDRG members was not affected. Together, our results suggest that pathophysiological PKC-mediated activation of NDRG1 may be a response mechanism to metabolic stress and anticancer agents.
Project description:SKBR3 cells expressing NDRG1 shRNA1 or vector control were harvested by trypsinization and total RNA was extracted. Silencing NDRG1 reduces cell proliferation rates, causing lipid metabolism dysfunction including increased fatty acid incorporation into neutral lipids and lipid droplets. global changes in transcriptome due to NDRG1 silencing were observed
Project description:NDRG1 functions as a metastasis suppressor in pancreatic and other cancers. To determine the molecular function of NDRG1 in MIAPaCa-2 pancreatic cancer cells, we performed a whole genome gene array analysis on these cells stably transfected with NDRG1 when compared to empty vector-transfected controls. The differentially expressed genes indetified in this microarray may represent potential molecular targets of NDRG1 in pancreatic cancer.
Project description:Hypoxia can lead to solid tumor aggressiveness by driving multiple signaling pathways. Long non-coding RNAs respond to several extrinsic stimuli, causing changes in cancer cells by participating in multiple steps of gene expression. However, genomic profiling of long non-coding RNAs regulated by oxygen in breast cancer remained unclear. Therefore, the aims of this study were to identify oxygen-responsive long non-coding RNAs in breast cancer cells, and to delineate their regulatory mechanisms. The expression profiling of long non-coding RNAs in breast cancer cells growing under normoxic, hypoxic, and re-oxygenated conditions was examined using next-generation sequencing technology. Four hundred and seventy-two lncRNAs oxygen-responsive lncRNAs were identified. After examining the top three differentially expressed lncRNAs in hypoxia, we selected N-Myc Downstream Regulated Gene 1-Overlapping 1 (NDRG1-OT1) for further study, especially the most responsive isoform, NDRG1-OT1_v4. We overexpressed NDRG1-OT1_v4 under normoxia and performed microarray analysis to identify 108 NDRG1-OT1_v4 regulated genes and their functions. Among these genes, we found that both NDRG1 mRNA expression and NDRG1 protein levels were inhibited by NDRG1-OT1_v4. Finally, we used co-immunoprecipitation to show that NDRG1-OT1_v4 destabilizes NDRG1 by promoting ubiquitin-mediated proteolysis. Our findings reveal a new type of epigenetic regulation of NDRG1 by NDRG1-OT1_v4 in breast cancer cells.