Project description:To identify differentially regulated genes between wild-type and Pak1 deficient mouse breast cancer cells, we performed a comparative gene profiling study by using mouse whole genome arrays. We compared the gene expression profiles of Her2 positive : Pak1 deficient cells vs Her2 positive : Pak1 wild type cells. All the experiments were performed in duplicate using tumor derived cells from two different tumors per group.
Project description:To identify differentially regulated genes between wild-type and Pak1 deficient human breast cancer cells, we performed a comparative gene profiling study by using human whole genome arrays.
Project description:To identify differentially regulated genes between wild-type and Pak1 deficient human breast cancer cells, we performed a comparative gene profiling study by using human whole genome arrays. We compared the gene expression profiles of MCF10A.B2 cells (MCF10A cells expressing a chemically activatable form of Her2) stably expressing a Tet inducible shRNA directed against Pak1 gene. All the experiments were performed in duplicate using tumor derived cells from two different tumors per group.
Project description:To identify differentially phosphorylated proteins between wild-type and Pak1-deficient mouse breast cancer cells, we performed a comparative study by using phospho-antibody arrays.
Project description:To identify differentially regulated genes between wild-type and Pak1 deficient mouse breast cancer cells, we performed a comparative gene profiling study by using mouse whole genome arrays.
Project description:Breast cancer is a highly heterogeneous disease, representing the most frequent malignancy and the second leading cause of cancer-related mortality in women worldwide. Among breast cancer subtypes, estrogen receptor-positive (ER+) tumors are often treated with endocrine therapies such as Tamoxifen or aromatase inhibitors (AIs), aimed at disrupting estrogen signaling. While these therapies are initially effective, up to 40% of patients eventually develop resistance, leading to disease relapse. The kinase p21-activated kinase 1 (PAK1), a key regulator of multiple oncogenic signaling pathways, has been previously implicated in resistance to Tamoxifen. However, its role in driving resistance to aromatase inhibitors remains unclear. In this study, we demonstrate that PAK1 contributes to resistance in both Tamoxifen and AI therapy contexts. Using global phospho-proteomic profiling, we observed elevated PAK1 activity in cell line models resistant to both therapies, with further increases following EGF stimulation. Notably, PAK1 inhibition effectively reduced cell proliferation in both resistance models, albeit with distinct effects on downstream PAK1 substrates. Our findings position PAK1 as a common mediator of resistance to endocrine therapies and offer valuable insights into the specific signaling networks involved in this process. These results suggest that targeting PAK1 may present a novel therapeutic strategy to overcome resistance in ER+ breast cancer, enhancing the efficacy of both Tamoxifen and AI treatments.
Project description:Pak1 as a serine/threonine kinase, has been implicated in cytoskeletal remodelling, cell motility, apoptosis and transformation. Pak1 plays important roles in multiple signal pathways. Pak1 protects cells from apoptosis through at least three different pathways including forkhead box O1 (FOXO1), B-cell CLL/lymphoma 2 (Bcl-2) and DLC1. Pak1 also regulates activity of Raf and Aurora kinases to affect cellular proliferation. Overexpression of Pak1 is involved in the regulation of actin assembly and disassembly through phosphorylations of LIM Kinase and cytoskeletal associated proteins such as Filamin A, Paxillin, Caldesmon, Cortactin and Arp2/3. Pak1 also regulates microtubule dynamics via activation of tubulin cofactor B (TCoB) and DLC1, and inhibition of stathmin. In spite of a large body of work about the mechanism of Pak1 action in cancer, it remains unknown whether Pak1 signaling could potentially regulate the biology of regulatory miRNAs. This is particularly relevant for gastric cancer because Pak1 can activate many regulators of miRNAs expression in gastric cancer cells including NF-kappaB and ERK, and Pak1 signaling has profound phenotypic effects on the biology of gastric cancer cells. We constructed Pak1 knockdown stable cell lines. The stable Pak1 knockdown gastric cancer BGC823 cells and control cells were performed miRNA chip analysis by CapitalBio company. Gastric cancer BGC823 cells with stable Pak1 knockdown and BGC-823 gastric cancer cells transfected with U6 were used in this experiment. Total RNA was extracted by trizol,Here we use a Capitalbio mammal microRNA V3.0(CapitalBio, Beijing, China) containing 509 well-characterized human, mouse and rat miRNAs and various controls to profile the expression levels of miRNA in 16 and conU6 group.three chip were test in each group, and the procedure was repeated twice.
