Project description:To investigate the molecular mechanism that triggers endoplasmic reticulum (ER) stress-induced cellular senescence in breast cancer cells, we established MCF7 cell lines exposed to ATF6α ectopic expression. We then performed gene expression profiling analysis using data obtained from RNA-seq of 9 different cells at three time points.
Project description:Overcoming cellular growth restriction, including the evasion of cellular senescence, is a hallmark of cancer. We report that PAK4 is overexpressed in all human breast cancer subtypes and associated with poor patient outcome. In mice, MMTV-PAK4 overexpression promotes spontaneous mammary cancer, while PAK4 gene depletion delays MMTV-PyMT driven tumors. Importantly, PAK4 prevents senescence-like growth arrest in breast cancer cells in vitro, in vivo and ex vivo, but is not needed in non-immortalized cells, while PAK4 overexpression in untransformed human mammary epithelial cells abrogates H-Ras-V12-induced senescence. Mechanistically, a PAK4 – RELB - C/EBPa axis controls the senescence-like growth arrest and a PAK4 phosphorylation residue (RELB-Se151) is critical for RELB-DNA interaction, transcriptional activity and expression of the senescence regulator C/EBPa. These findings establish PAK4 as a promoter of breast cancer that can overcome oncogene-induced senescence and reveal a selective vulnerability of cancer to PAK4 inhibition.
Project description:Sprague-Dawley (SD) rat pups exposed to room air (NOX) or 95% O2 (HOX) from P1-P10 to study the role of cellular senescence in bronchopulmonary dysplasia (BPD). Markers of cellular senescence in the lungs were obtained at P10 and P21. ScRNAseq of the lungs were obtained at P10 to study cell type-specific cellular senescence.