Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 in...Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 induces p53-dependent apoptosis,whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest.Compared to Mdm4 deletion,Mdm2 deletion causes more severe phenotypic defects.Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53,suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis.Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis,which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes.Studies from these mouse models strongly suggest that blocking Mdm2and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.展开更多
Mouse double minute （Mdm） genes span an evolutionary timeframe from the ancient eukaryotic placozoa Trichoplox adhaerens to Homo sapiens, implying a significant and possibly conserved cellular role throughout histor...Mouse double minute （Mdm） genes span an evolutionary timeframe from the ancient eukaryotic placozoa Trichoplox adhaerens to Homo sapiens, implying a significant and possibly conserved cellular role throughout history. Maintenance of DNA integrity and response to DNA damage involve many key regulatory pathways, including precise control over the tumour suppressor pro- tein p53. In most vertebrates, degradation of p53 through proteasomal targeting is primarily mediated by heterodimers of Mdm2 and the Mdm2-related protein Mdm4 （also known as MdmX）. Both Mdm2 and Mdm4 have p53-binding regions, acidic domains, zinc fingers, and C-terminal RING domains that are conserved throughout evolution. Vertebrates typically have both Mdm2 and Mdm# genes, while analyses of sequenced genomes of invertebrate species have identified single Mdm genes, suggesting that a duplication event occurred prior to emergence of jawless vertebrates about 550-440 million years ago. The functional relationship between Mdm and p53 in T. adhaerens, an organism that has existed for 1 billion years, implies that these two proteins have evolved together to maintain a conserved and regulated function.展开更多
The major cause of death from breast cancer is not the primary turnout, but relapsing, drug-resistant, metastatic disease. Identifying factors that contribute to aggressive cancer offers important leads for therapy. I...The major cause of death from breast cancer is not the primary turnout, but relapsing, drug-resistant, metastatic disease. Identifying factors that contribute to aggressive cancer offers important leads for therapy. Inherent defence against carcinogens depends on the individual molecular make-up of each person. Important molecular determinants of these responses are under the control of the mouse double minute （MDM） family： comprised of the proteins MDM2 and MDM4. In normal, healthy adult cells, the MDM family functions to critically regulate measured, cellular responses to stress and subsequent recovery. Proper function of the MDM family is vital for normal breast development, but also for preserving genomic fidelity. The MDM family members are best characterized for their negative regulation of the major tumour suppressor p53 to modulate stress responses. Their impact on other cellular regulators is emerging. Inappropriately elevated protein levels of the MDM family are highly associated with an increased risk of cancer incidence. Exploration of the MDM family members as cancer therapeutic targets is relerant for designing tailored anti-cancer treatments, but successful approaches must strategically consider the impact on both the target cancer and adjacent healthy ceils and tissues. This review focuses on recent findings pertaining to the role of the MDM family in normal and malignant breast cells.展开更多
Targeted therapies include small-molecule inhibitors and monoclonal antibodies, have made treatment more tumor-specific and less toxic, and have opened new possibilities for tailoring cancer treatment. Nevertheless, t...Targeted therapies include small-molecule inhibitors and monoclonal antibodies, have made treatment more tumor-specific and less toxic, and have opened new possibilities for tailoring cancer treatment. Nevertheless, there remain several challenges to targeted therapies, including molecular identification, drug resistance, and exploring reliable biomarkers. Here, we present several selected signaling pathways and molecular targets involved in human cancers including Aurora kinases, PI3K/mTOR signaling, FOXO-FOXM1 axis, and MDM2/MDM4-p53 interaction. Understanding the molecular mechanisms for tumorigenesis and development of drug resistance will provide new insights into drug discovery and design of therapeutic strategies for targeted therapies.展开更多
文摘Mdm2 and Mdm4 are two key negative regulators of the tumor suppressor p53.Deletion of either Mdm2 or Mdm4 induces p53-dependent early embryonic lethality in knockout mouse models.The tissuespecific deletion of Mdm2 induces p53-dependent apoptosis,whereas the deletion of Mdm4 induces both p53-dependent apoptosis and cell cycle arrest.Compared to Mdm4 deletion,Mdm2 deletion causes more severe phenotypic defects.Disrupting the Mdm2 and Mdm4 interaction using knockin mice models causes embryonic lethality that can be completely rescued by the concomitant loss of p53,suggesting that Mdm2 and Mdm4 heterodimerization is critical to inhibit p53 activity during embryogenesis.Overexpression of Mdm2 and Mdm4 in mice induces spontaneous tumorigenesis,which clearly indicates that Mdm2 and Mdm4 are bona fide oncogenes.Studies from these mouse models strongly suggest that blocking Mdm2and Mdm4-mediated p53 inhibition is an appealing therapeutic strategy for cancer patients with wild-type p53 alleles.
文摘Mouse double minute （Mdm） genes span an evolutionary timeframe from the ancient eukaryotic placozoa Trichoplox adhaerens to Homo sapiens, implying a significant and possibly conserved cellular role throughout history. Maintenance of DNA integrity and response to DNA damage involve many key regulatory pathways, including precise control over the tumour suppressor pro- tein p53. In most vertebrates, degradation of p53 through proteasomal targeting is primarily mediated by heterodimers of Mdm2 and the Mdm2-related protein Mdm4 （also known as MdmX）. Both Mdm2 and Mdm4 have p53-binding regions, acidic domains, zinc fingers, and C-terminal RING domains that are conserved throughout evolution. Vertebrates typically have both Mdm2 and Mdm# genes, while analyses of sequenced genomes of invertebrate species have identified single Mdm genes, suggesting that a duplication event occurred prior to emergence of jawless vertebrates about 550-440 million years ago. The functional relationship between Mdm and p53 in T. adhaerens, an organism that has existed for 1 billion years, implies that these two proteins have evolved together to maintain a conserved and regulated function.
文摘The major cause of death from breast cancer is not the primary turnout, but relapsing, drug-resistant, metastatic disease. Identifying factors that contribute to aggressive cancer offers important leads for therapy. Inherent defence against carcinogens depends on the individual molecular make-up of each person. Important molecular determinants of these responses are under the control of the mouse double minute （MDM） family： comprised of the proteins MDM2 and MDM4. In normal, healthy adult cells, the MDM family functions to critically regulate measured, cellular responses to stress and subsequent recovery. Proper function of the MDM family is vital for normal breast development, but also for preserving genomic fidelity. The MDM family members are best characterized for their negative regulation of the major tumour suppressor p53 to modulate stress responses. Their impact on other cellular regulators is emerging. Inappropriately elevated protein levels of the MDM family are highly associated with an increased risk of cancer incidence. Exploration of the MDM family members as cancer therapeutic targets is relerant for designing tailored anti-cancer treatments, but successful approaches must strategically consider the impact on both the target cancer and adjacent healthy ceils and tissues. This review focuses on recent findings pertaining to the role of the MDM family in normal and malignant breast cells.
文摘Targeted therapies include small-molecule inhibitors and monoclonal antibodies, have made treatment more tumor-specific and less toxic, and have opened new possibilities for tailoring cancer treatment. Nevertheless, there remain several challenges to targeted therapies, including molecular identification, drug resistance, and exploring reliable biomarkers. Here, we present several selected signaling pathways and molecular targets involved in human cancers including Aurora kinases, PI3K/mTOR signaling, FOXO-FOXM1 axis, and MDM2/MDM4-p53 interaction. Understanding the molecular mechanisms for tumorigenesis and development of drug resistance will provide new insights into drug discovery and design of therapeutic strategies for targeted therapies.
