Cyclin-dependent kinase 1 （Cdkl）/cyclin B1 complex is the driving force for mitotic entry, and its activation is tightly regulated by the G2/M checkpoint. We originally reported that a novel protein C53 （also known...Cyclin-dependent kinase 1 （Cdkl）/cyclin B1 complex is the driving force for mitotic entry, and its activation is tightly regulated by the G2/M checkpoint. We originally reported that a novel protein C53 （also known as Cdk5rap3 and LZAP） potentiates DNA damage-induced cell death by modulating the G2/M checkpoint. More recently, Wang et al. （2007） found that C53/LZAP may function as a tumor suppressor by way of inhibiting NF-kB signaling. We re- port here the identification of C53 protein as a novel regulator of Cdkl activation. We found that knockdown of C53 protein causes delayed Cdkl activation and mitotic entry. During DNA damage response, activation of checkpoint kinase 1 and 2 （Chkl and Chk2） is partially inhibited by C53 overexpression. Intriguingly, we found that C53 inter- acts with Chkl and antagonizes its function. Moreover, a portion of C53 protein is localized at the centrosome, and centrosome-targeting C53 potently promotes local Cdkl activation. Taken together, our results strongly suggest that C53 is a novel negative regulator of checkpoint response. By counteracting Chkl, C53 promotes Cdkl activation and mitotic entry in both unperturbed cell-cycle progression and DNA damage response.展开更多
Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing intere...Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing interest in treatments that target the cell cycle.A large international effort has led to the development of a large number of inhibitors,which target cell cycle kinases,including cyclin-dependent kinases,Aurora kinases and polo-like kinase.Initial phase Ⅰ/Ⅱ trials in solid tumors have often demonstrated only modest clinical benefits of monotherapy.This may relate in part to a failure to identify the patient populations that will gain the most clinical benefit.Newer compounds lacking the side effect profile of first-generation compounds may show utility as adjunctive treatments targeted to an individual's predicted response to treatment.展开更多
文摘Cyclin-dependent kinase 1 （Cdkl）/cyclin B1 complex is the driving force for mitotic entry, and its activation is tightly regulated by the G2/M checkpoint. We originally reported that a novel protein C53 （also known as Cdk5rap3 and LZAP） potentiates DNA damage-induced cell death by modulating the G2/M checkpoint. More recently, Wang et al. （2007） found that C53/LZAP may function as a tumor suppressor by way of inhibiting NF-kB signaling. We re- port here the identification of C53 protein as a novel regulator of Cdkl activation. We found that knockdown of C53 protein causes delayed Cdkl activation and mitotic entry. During DNA damage response, activation of checkpoint kinase 1 and 2 （Chkl and Chk2） is partially inhibited by C53 overexpression. Intriguingly, we found that C53 inter- acts with Chkl and antagonizes its function. Moreover, a portion of C53 protein is localized at the centrosome, and centrosome-targeting C53 potently promotes local Cdkl activation. Taken together, our results strongly suggest that C53 is a novel negative regulator of checkpoint response. By counteracting Chkl, C53 promotes Cdkl activation and mitotic entry in both unperturbed cell-cycle progression and DNA damage response.
基金Supported by UK National Institute of Health Research/Cancer Research Network and Research and Development Department of Wrightington Wigan and Leigh NHS Foundation Trust (to Ang YS)Wrightington Wigan and Leigh NHS Foundation Trust Cancer Therapy Fund (to Dibb M)
文摘Esophageal adenocarcinoma is a major cause of cancer death in men in the developed world.Continuing poor outcomes with conventional therapies that predominantly target apoptosis pathways have lead to increasing interest in treatments that target the cell cycle.A large international effort has led to the development of a large number of inhibitors,which target cell cycle kinases,including cyclin-dependent kinases,Aurora kinases and polo-like kinase.Initial phase Ⅰ/Ⅱ trials in solid tumors have often demonstrated only modest clinical benefits of monotherapy.This may relate in part to a failure to identify the patient populations that will gain the most clinical benefit.Newer compounds lacking the side effect profile of first-generation compounds may show utility as adjunctive treatments targeted to an individual's predicted response to treatment.
