Project description:Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous population of neoplasms that arise from hormone-secreting islet cells of the pancreas and have increased markedly in incidence over the past four decades. Non-functional PanNETs, which occur more frequently than hormone-secreting tumors, are often not diagnosed until later stages of tumor development and have poorer prognoses. Development of successful therapeutics for PanNETs has been slow, partially due to a lack of diverse animal models for pre-clinical testing. Here, we report development of an inducible, conditional mouse model of PanNETs by using a bitransgenic system for regulated expression of the aberrant activator of Cdk5, p25, specifically in b-islet cells. This model produces a heterogeneous population of PanNETs that includes a subgroup of well-differentiated, non-functional tumors. The utility of this model is enhanced by ability to form tumor-derived allografts. Production of these tumors demonstrates the causative potential of aberrantly active Cdk5 for generation of PanNETs. Further, we show that human PanNETs express Cdk5 pathway components, are dependent on Cdk5 for growth, and share genetic and transcriptional overlap with the INS-p25OE model. This new model of PanNETs will facilitate molecular delineation of Cdk5-dependent PanNETs and the development of new targeted therapeutics.
Project description:Pancreatic neuroendocrine neoplasms (PNENs) are biologically and clinically heterogeneous neoplasms. We used quantitative global proteomic analysis on 40 PNENs to compliment paired transcriptome data.
Project description:Despite the development of adjuvant therapies, glioblastoma (GBM) patients remain incurable and justify the urgent need of new therapies. CDK5 functions a critical role in GBM and is a potential target for GBM. However, the mechanism by which CDK5 promotes GBM tumorigenicity remains largely unknown. Here we identify TRIM59 as a substrate of CDK5. EGFR-activated CDK5 directly binds to and phosphorylates TRIM59, a ubiquitin ligase at serine 308, which recruits PIN1 for cis-trans isomerization of TRIM59, leading to TRIM59 binding to importin a5 and nuclear translocation. Nuclear TRIM59 induces ubiquitination and degradation of the tumor suppressive histone variant macroH2A1, leading to enhanced STAT3 signaling activation and tumorigenicity. These findings are confirmed by inhibition of CDK5-activated TRIM59 activity that results in suppression of intracranial tumor growth. Correlative expressions of the components of this pathway are clinically prognostic. Our findings suggest targeting CDK5/TRIM59 signaling axis as a putative strategy for treating GBM.
Project description:To investigate the molecular mechanism underlying activity-dependent dendrite development regulated by Cdk5, an unbiased microarray analysis was performed to identify activity-dependent genes differentially regulated in cortical neurons from E18 Cdk5-knockout embryos.
Project description:Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that shows high infiltration of cancer stem cells (CSCs), which correlates with poor clinical outcome. Here, we have demonstrated that an aberrant activation of CDK5/pho-PPARg axis associated with TNBC progression closely. CDK5 blockade sufficiently abrogates stemness transformation of TNBC cells, resulting in a significant inhibition of tumor metastatic progression. Moreover, CDK5 inhibitor Rosc attenuates CD44v+ BCSCs, hereby reversing immunosuppressive microenvironment and enhancing anti-PD-1 effects on TNBC. Mechanistically, CDK5/pho-PPARgaxis modulates the ESRP1 degradation via E3 ligase-like activity, leading to CD44 variant (CD44v) expression. Our finding indicates that CDK5 blockade could be a potent strategy to target CSCs in TNBC, and to increase the response to PD-1 blockade in TNBC therapy.
Project description:Assessment of mesenteric fibrosis (MF) presence and severity in small-intestinal neuroendocrine tumors (SI-NETs) remains a diagnostic challenge. To explore possible biomarkers for MF presence, a proteomic analysis was performed of the tumor and stroma compartment of primary SI-NETs and paired mesenteric metastasis.