Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

CHK1 Inhibitor Blocks Phosphorylation of FAM122A and Promotes Replication Stress

ABSTRACT: While effective anti-cancer drugs targeting the CHK1 kinase are advancing in the clinic, drug resistance is rapidly emerging. Here, we demonstrate that CRISPR-mediated knockout of the little-known gene FAM122A confers cellular resistance to CHK1 inhibitors and cross-resistance to ATR inhibitors. Knockout of FAM122A results in activation of PP2A-B55α, a phosphatase which dephosphorylates the WEE1 protein and rescues WEE1 from Ubiquitin-mediated degradation. The resulting increase in WEE1 protein expression reduces replication stress, activates the G2/M checkpoint, and confers cellular resistance to CHK1 inhibitors. Interestingly, in tumor cells with oncogene-driven replication stress, CHK1 can directly phosphorylate FAM122A, leading to activation of the PP2A-B55α phosphatase and increased WEE1 expression. A combination of a CHK1 inhibitor plus a WEE1 inhibitor can overcome CHK1 inhibitor resistance of these tumor cells, thereby enhancing anti-cancer activity. The FAM122A expression level in a tumor cell can serve as a useful biomarker for predicting CHK1 inhibitor sensitivity or resistance.

ORGANISM(S): Homo sapiens

PROVIDER: GSE158338 | GEO | 2021/01/01

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

FAM122A is required for mesendodermal and cardiac differentiation of embryonic stem cells [ChIP-seq]

Project description:Mesendodermal specification and cardiac differentiation are key issues for developmental biology and heart regeneration medicine. Previously, we demonstrated that FAM122A, a highly conserved house-keeping gene, is an endogenous inhibitor of protein phosphatase 2A (PP2A) and participates in multi facet physiological and pathological processes, however, the in vivo function of FAM122A is largely unknown. In this study, we found that Fam122 deletion results in embryonic lethality with severe defects of cardiovascular developments and significantly attenuates the cardiac functions in conditional cardiac-specific knockout mice. More importantly, Fam122a deficiency impairs mesendodermal specification and cardiac differentiation from mouse embryonic stem cells, but not influences the pluripotent identity. Mechanical investigation shows that the impaired differentiation potential is caused through the dysregulation of histone modification and Wnt and Hippo signaling pathways by modulating PP2A activity. These findings suggest that FAM122A is a novel and critical regulator in mesendodermal specification and cardiac differentiation. This not only significantly extends our understanding the regulatory network of mesendodermal/cardiac differentiation, but also establishes a previously uncharacterized connection between PP2A and mesendodermal specification.

2022-08-18 | GSE211235 | GEO

FAM122A is required for mesendodermal and cardiac differentiation of embryonic stem cells [RNA-seq]

2022-08-18 | GSE211234 | GEO

Clusterin knockdown sensitizes prostate cancer cells to taxane by modulating mitosis

Project description:Clusterin (CLU) is a stress-activated molecular chaperone that confers treatment resistance to taxanes when highly expressed. While CLU inhibition potentiates activity of taxanes and other anti-cancer therapies in preclinical models, progression to treatment resistant disease still occurs implicating additional compensatory survival mechanisms. Taxanes are believed to selectively target cells in mitosis, a complex mechanism controlled in part by balancing antagonistic roles of Cdc25C and Wee1 in mitosis progression. Our data indicate that CLU silencing induces a constitutive activation of Cdc25C, which delays mitotic exit and hence sensitizes cancer cells to mitotic-targeting agents such taxanes. Unchecked Cdc25C activation leads to mitotic catastrophe and cell death unless cells upregulate protective mechanisms mediated through the cell cycle regulators Wee1 and Cdc2. In this study we show that CLU silencing induces a constitutive activation of Cdc25C via the phosphatase PP2A but leads to relief of negative feedback inhibition and activation of Wee1-Cdc2 to promote survival and limit therapeutic efficacy. Simultaneous inhibition of CLU-regulated cell cycle effectors, like PP2A and Wee1, may improve synergistic responses of biologically rational combinatorial regimens using taxanes and CLU inhibitors Biological triplicate of PC3 treated with siClusterin were compared to biological trplicate of PC3 treated with siScramblein

2016-03-01 | E-GEOD-67256 | biostudies-arrayexpress

CHK1 Inhibitor Blocks Phosphorylation of FAM122A and Promotes Replication Stress

Project description:CHK1 Inhibitor Blocks Phosphorylation of FAM122A and Promotes Replication Stress

| PRJNA664943 | ENA

Clusterin knockdown sensitizes prostate cancer cells to taxane by modulating mitosis

2016-03-01 | GSE67256 | GEO

CDK2-mediated TNFa Upregulation as a Mechanism of Cytotoxicity in Acute Leukemia

Project description:Although inhibitors of the kinases CHK1, ATR and WEE1 are undergoing clinical testing, it remains unclear how these three classes of agents kill susceptible cells and whether they utilize the same cytotoxic mechanism. Here we observed that CHK1 inhibition induces apoptosis in a subset of acute leukemia cell lines, including TP53 null acute myeloid leukemia (AML) and BCR/ABL-positive acute lymphoid leukemia (ALL), in vitro and inhibits leukemic colony formation in clinical AML samples ex vivo. In further studies, CHK1 downregulation or CHK1 inhibitor treatment triggered signaling in sensitive human acute leukemia cell lines that involved CDK2 activation followed by AP1-dependent TNF transactivation, TNF production and engagement of a TNFR1- and BID-dependent apoptotic pathway. AML lines that were intrinsically CHK1 inhibitor resistant exhibited high CHK1 expression and were sensitized by CHK1 downregulation. Signaling through this same CDK2  AP1  TNF cytotoxic pathway was also initiated by ATR or WEE1 inhibitors in vitro and during CHK1 inhibitor treatment of AML xenografts in vivo. Collectively, these observations not only identify new contributors to antileukemic cell action of CHK1, ATR and WEE1 inhibitors, but also delineate a previously undescribed pathway leading from aberrant CDK2 activation to death ligand-induced killing that can potentially be exploited for acute leukemia treatment.

2020-12-28 | GSE131912 | GEO

TRRAP-mediated regulation of Wee1

Project description:The G2 DNA damage checkpoint inhibits Cdc2 and mitotic entry through the dual regulation of Wee1 and Cdc25 by the Chk1 effector kinase. Up-regulation of Chk1 by mutation or overexpression bypasses the requirement for up-stream regulators or DNA damage to promote a G2 cell cycle arrest. We screened in fission yeast for mutations that rendered cells resistant to overexpressed Chk1. We identified a mutation in tra1, which encodes one of two homologs of TRRAP, an ATM/R-related pseudokinase that scaffolds several histone acetyltransferase (HAT) complexes. Inhibition of histone deacetylases reverts the resistance to overexpressed Chk1, suggesting this phenotype is due to a HAT activity, though expression of checkpoint and cell cycle genes is not greatly affected. Cells with mutant or deleted tra1 activate Chk1 normally and are checkpoint proficient. However, these cells are semi-wee even when overexpressing Chk1, and accumulate inactive Wee1 protein. The Cdr (changed division response) kinases Cdr1 and Cdr2 are negative regulators of Wee1, and while best characterized in the cellular response to limited nutrition, we show that they are required for the Tra1-dependent alterations to Wee1 function. This identifies Tra1 as another component controlling the timing of entry into mitosis via Cdc2 activation. Two and three independent microaaray experiments were done for wild type and the mutant (tra1-1) respectively.

2010-04-11 | E-GEOD-12674 | biostudies-arrayexpress

Increased HDAC Activity and c-MYC Expression Mediate Acquired Resistance to WEE1 Inhibition in Acute Leukemia

Project description:WEE1 is a cell cycle and DNA damage response kinase that is emerging as a therapeutic target for cancer. AZD1775 is a small molecule inhibitor of WEE1, currently in early phase clinical trials as a single agent and in combination with more conventional anti-neoplastic agents. As resistance to kinase inhibitors is frequent, we sought to identify mechanisms of resistance to WEE1 inhibition in acute leukemia. We found that AZD1775 resistant cell lines are dependent upon increased HDAC activity for their survival, in part due to increased KDM5A activity. In addition, gene expression analyses demonstrate HDAC dependent increase in MYC expression and c-MYC activity in AZD1775 treated resistant cells. Overexpression of c-MYC confers resistance to AZD1775 in cell lines with low base line expression. Pharmacologic inhibition of BRD4, and thereby c-MYC, partially abrogated resistance to AZD1775. Thus, acquired resistance to WEE1 inhibition may be reversed by HDAC or BRD4 inhibition in leukemia cells.

2020-02-25 | GSE145129 | GEO

Transcriptomics analysis of FAM122A knockout and NC K562 cells

Project description:To understand the molecular mechanism associated with increased erythroid differentiation upon FAM122A deletion, we performed RNA sequencing to examine the global gene expression profiling of FAM122A KO and NC K562 cells.

2020-07-30 | GSE141735 | GEO

Identification of Fam122a regulated genes in LT-HSCs.

Project description:We report differences in gene expression between WT and Fam122a KO LT-HSCs.

2020-05-28 | GSE151261 | GEO