Project description:Phenotypically, there is a heterogeneous response of cancer cells to chemotherapy or targeted therapy. While therapeutically much attention is focused on cell death, there is growing evidence suggesting that a subpopulation of cancer cells undergo therapy-induced senescence. Depending on the therapy, dose and timing, senescence may be a dominant phenotype over cell death. An integrated FACS approach identified two types of therapy-induced senescence in human melanoma cells, irreversible senescence induced by Aurora kinase inhibition vs. transient senescence induced by B-RAF kinase inhibition. Autophagy and ER stress response precede and are required for therapy-induced senescence in cancer cells, mirroring their functions in normal cells undergoing oncogene-induced senescence. Importantly, autophagy serves a survival pathway for senescent cancer cells. Antagonizing autophagy converts therapy-induced senescence into cell death but paradoxically promotes cell proliferation or quiescence. Our work calls for a rationale-based design of combination therapy for cancer treatment that should lead to a greater synergy. There are three or four replicates per treatment per time point.
Project description:Phenotypically, there is a heterogeneous response of cancer cells to chemotherapy or targeted therapy. While therapeutically much attention is focused on cell death, there is growing evidence suggesting that a subpopulation of cancer cells undergo therapy-induced senescence. Depending on the therapy, dose and timing, senescence may be a dominant phenotype over cell death. An integrated FACS approach identified two types of therapy-induced senescence in human melanoma cells, irreversible senescence induced by Aurora kinase inhibition vs. transient senescence induced by B-RAF kinase inhibition. Autophagy and ER stress response precede and are required for therapy-induced senescence in cancer cells, mirroring their functions in normal cells undergoing oncogene-induced senescence. Importantly, autophagy serves a survival pathway for senescent cancer cells. Antagonizing autophagy converts therapy-induced senescence into cell death but paradoxically promotes cell proliferation or quiescence. Our work calls for a rationale-based design of combination therapy for cancer treatment that should lead to a greater synergy. There are three or four replicates per treatment per time point.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression. Two-condition experiment, Normoxic MSCs vs. Hypoxic MSCs.
Project description:Phenotypically, there is a heterogeneous response of cancer cells to chemotherapy or targeted therapy. While therapeutically much attention is focused on cell death, there is growing evidence suggesting that a subpopulation of cancer cells undergo therapy-induced senescence. Depending on the therapy, dose and timing, senescence may be a dominant phenotype over cell death. An integrated FACS approach identified two types of therapy-induced senescence in human melanoma cells, irreversible senescence induced by Aurora kinase inhibition vs. transient senescence induced by B-RAF kinase inhibition. Autophagy and ER stress response precede and are required for therapy-induced senescence in cancer cells, mirroring their functions in normal cells undergoing oncogene-induced senescence. Importantly, autophagy serves a survival pathway for senescent cancer cells. Antagonizing autophagy converts therapy-induced senescence into cell death but paradoxically promotes cell proliferation or quiescence. Our work calls for a rationale-based design of combination therapy for cancer treatment that should lead to a greater synergy.
Project description:Phenotypically, there is a heterogeneous response of cancer cells to chemotherapy or targeted therapy. While therapeutically much attention is focused on cell death, there is growing evidence suggesting that a subpopulation of cancer cells undergo therapy-induced senescence. Depending on the therapy, dose and timing, senescence may be a dominant phenotype over cell death. An integrated FACS approach identified two types of therapy-induced senescence in human melanoma cells, irreversible senescence induced by Aurora kinase inhibition vs. transient senescence induced by B-RAF kinase inhibition. Autophagy and ER stress response precede and are required for therapy-induced senescence in cancer cells, mirroring their functions in normal cells undergoing oncogene-induced senescence. Importantly, autophagy serves a survival pathway for senescent cancer cells. Antagonizing autophagy converts therapy-induced senescence into cell death but paradoxically promotes cell proliferation or quiescence. Our work calls for a rationale-based design of combination therapy for cancer treatment that should lead to a greater synergy.
Project description:In this study, we have used techniques from cell biology, biochemistry, and genetics to investigate the role of the tyrosine phosphatase Shp2 in tumor cells of MMTV-PyMT mouse mammary glands. Genetic ablation or pharmacological inhibition of Shp2 induces senescence, as determined by the activation of senescence-associated ?-gal (SA-?-gal), cyclin-dependent kinase inhibitor 1B (p27), p53, and histone 3 trimethylated lysine 9 (H3K9me3). Senescence induction leads to inhibition of self-renewal of tumor cells and blockage of tumor formation and growth. A signaling cascade was identified that acts downstream of Shp2 to counter senescence: Src, Focal adhesion kinase and Map kinase inhibit senescence by activating the expression of S-phase kinase-associated protein 2 (Skp2), Aurora kinase A (Aurka), and the Notch ligand Delta-like 1 (Dll1), which block p27 and p53. Remarkably, the expression of Shp2 and of selected target genes predicts human breast cancer outcome. We conclude that therapies which rely on senescence induction by inhibiting Shp2 or controlling its target gene products may be useful in blocking breast cancer. Primary mammary tumor cells from MMTV-PyMT mice were cultured as mammospheres for 10 days and then treated with specific inhibitors of Notch (DAPT), MEK1 (U0126), FAK (TAE226), or Src (PP2) for another 2 days. Mammospheres were then subjected to RNA isolation. Each group contains 3 replicates.
Project description:In this study, we have used techniques from cell biology, biochemistry, and genetics to investigate the role of the tyrosine phosphatase Shp2 in tumor cells of MMTV-PyMT mouse mammary glands. Genetic ablation or pharmacological inhibition of Shp2 induces senescence, as determined by the activation of senescence-associated β-gal (SA-β-gal), cyclin-dependent kinase inhibitor 1B (p27), p53, and histone 3 trimethylated lysine 9 (H3K9me3). Senescence induction leads to inhibition of self-renewal of tumor cells and blockage of tumor formation and growth. A signaling cascade was identified that acts downstream of Shp2 to counter senescence: Src, Focal adhesion kinase and Map kinase inhibit senescence by activating the expression of S-phase kinase-associated protein 2 (Skp2), Aurora kinase A (Aurka), and the Notch ligand Delta-like 1 (Dll1), which block p27 and p53. Remarkably, the expression of Shp2 and of selected target genes predicts human breast cancer outcome. We conclude that therapies which rely on senescence induction by inhibiting Shp2 or controlling its target gene products may be useful in blocking breast cancer. For Shp2 ablation, primary mammary tumor cells from MMTV-PyMT;Shp2fl/fl mice were transduced with retroviruses expressing control GFP or CreERT2-GFP, and GFP-positive cells were purified by FACS and cultured as mammospheres for 1 week. Mammospheres were then treated with 50 nM 4-OHT for 2 hours, cultured for another 5 days, and subjected to RNA isolation. For pharmacological inhibition, primary mammary tumor cells from the same mice were cultured as mammospheres for 10 days and then treated with the Shp2 inhibitor GS493 for another 2 days. Mammospheres were then subjected to RNA isolation. Each group contains 3 replicates.