WEE1

Gene Summary

Gene:WEE1; WEE1 G2 checkpoint kinase
Aliases: WEE1A, WEE1hu
Location:11p15.4
Summary:This gene encodes a nuclear protein, which is a tyrosine kinase belonging to the Ser/Thr family of protein kinases. This protein catalyzes the inhibitory tyrosine phosphorylation of CDC2/cyclin B kinase, and appears to coordinate the transition between DNA replication and mitosis by protecting the nucleus from cytoplasmically activated CDC2 kinase. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:wee1-like protein kinase
Source:NCBIAccessed: 09 March, 2017

Ontology:

What does this gene/protein do?
Show (22)
Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 10 March 2017 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Nasopharyngeal Cancer
  • Cyclin-Dependent Kinases
  • Cell Proliferation
  • MicroRNAs
  • Drug Resistance
  • Cancer Gene Expression Regulation
  • Cell Cycle Proteins
  • Cell Cycle Checkpoints
  • Tyrosine
  • DNA Damage
  • Antineoplastic Agents
  • Tumor Stem Cell Assay
  • Gene Expression Profiling
  • Oligonucleotide Array Sequence Analysis
  • Mitosis
  • Phosphorylation
  • Checkpoint Kinase 1
  • Down-Regulation
  • Nuclear Proteins
  • Protein-Tyrosine Kinases
  • Chromosome 11
  • Western Blotting
  • Sequence Deletion
  • Prostate Cancer
  • Molecular Targeted Therapy
  • Pyrimidines
  • Mutation
  • Cell Cycle
  • Pyrazoles
  • Protein Kinase Inhibitors
  • RNA Interference
  • Messenger RNA
  • Apoptosis
  • Protein Kinases
  • Transcription
  • TGFB1
  • Cyclin B
  • Breast Cancer
  • G2 Phase Cell Cycle Checkpoints
  • Drug Synergism
Tag cloud generated 09 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: WEE1 (cancer-related)

Mohammadi A, Mansoori B, Aghapour M, et al.
The Urtica dioica extract enhances sensitivity of paclitaxel drug to MDA-MB-468 breast cancer cells.
Biomed Pharmacother. 2016; 83:835-842 [PubMed] Related Publications
INTRODUCTION: Due to the chemo resistant nature of cancer cells and adverse effects of current therapies, researchers are looking for the most efficient therapeutic approach which has the lowest side effects and the highest toxicity on cancer cells. The aim of the present study was to investigate the synergic effect of Urtica dioica extract in combination with paclitaxel on cell death and invasion of human breast cancer MDA-MB-468 cell line.
MATERIALS AND METHODS: To determine the cytotoxic effects of Urtica dioica extract with paclitaxel, MTT assay was performed. The scratch test was exploited to assess the effects of Urtica dioica, Paclitaxel alone and combination on migration of cancer cells. The expression levels of snail-1, ZEB1, ZEB2, twist, Cdc2, cyclin B1 and Wee1 genes were quantified using qRT-PCR and western blot performed for snail-1expression. The effects of plant extract, Paclitaxel alone and combination on different phases of cell cycle was analyzed using flow cytometry.
RESULTS: Results of MTT assay showed that Urtica dioica significantly destroyed cancer cells. Interestingly, Concurrent use of Urtica dioica extract with paclitaxel resulted in decreased IC50 dose of paclitaxel. Moreover, findings of scratch assay exhibited the inhibitory effects of Urtica dioica, Paclitaxel alone and combination on migration of MDA-MB-468 cell line. Our findings also demonstrated that the extract substantially decreased the Snail-1 and related gene expression. Ultimately, Cell cycle arrest occurred at G2/M phase post-treatment by deregulating Cdc2 and wee1.
CONCLUSIONS: Our results demonstrated that the dichloromethane extract of Urtica dioica inhibit cell growth and migration. Also, Urtica dioica extract substantially increased sensitivity of breast cancer cells to paclitaxel. Therefore, it can be used as a potential candidate for treatment of breast cancer with paclitaxel.

Liu KC, Shih TY, Kuo CL, et al.
Sulforaphane Induces Cell Death Through G2/M Phase Arrest and Triggers Apoptosis in HCT 116 Human Colon Cancer Cells.
Am J Chin Med. 2016; 44(6):1289-1310 [PubMed] Related Publications
Sulforaphane (SFN), an isothiocyanate, exists exclusively in cruciferous vegetables, and has been shown to possess potent antitumor and chemopreventive activity. However, there is no available information that shows SFN affecting human colon cancer HCT 116 cells. In the present study, we found that SFN induced cell morphological changes, which were photographed by contrast-phase microscopy, and decreased viability. SFN also induced G2/M phase arrest and cell apoptosis in HCT 116 cells, which were measured with flow cytometric assays. Western blotting indicated that SFN increased Cyclin A, cdk 2, Cyclin B and WEE1, but decreased Cdc 25C, cdk1 protein expressions that led to G2/M phase arrest. Apoptotic cell death was also confirmed by Annexin V/PI and DAPI staining and DNA gel electrophoresis in HCT 116 cells after exposure to SFN. The flow cytometric assay also showed that SFN induced the generation of reactive oxygen species (ROS) and Ca[Formula: see text] and decreased mitochondria membrane potential and increased caspase-8, -9 and -3 activities in HCT 116 cell. Western blotting also showed that SFN induced the release of cytochrome c, and AIF, which was confirmed by confocal microscopy examination. SFN induced ER stress-associated protein expression. Based on those observations, we suggest that SFN may be used as a novel anticancer agent for the treatment of human colon cancer in the future.

Huisman SA, Ahmadi AR, IJzermans JN, et al.
Disruption of clock gene expression in human colorectal liver metastases.
Tumour Biol. 2016; 37(10):13973-13981 [PubMed] Free Access to Full Article Related Publications
The circadian timing system controls about 40 % of the transcriptome and is important in the regulation of a wide variety of biological processes including metabolic and proliferative functions. Disruption of the circadian clock could have significant effect on human health and has an important role in the development of cancer. Here, we compared the expression levels of core clock genes in primary colorectal cancer (CRC), colorectal liver metastases (CRLM), and liver tissue within the same patient. Surgical specimens of 15 untreated patients with primary CRC and metachronous CRLM were studied. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of 10 clock genes: CLOCK, BMAL1, PER1, PER2, PER3, CRY1, CRY2, CSNK1E, TIM, TIPIN, and 2 clock-controlled genes: Cyclin-D1, and WEE1. Expression levels of 7 core clock genes were downregulated in CRLM: CLOCK (p = 0.006), BMAL1 (p = 0.003), PER1 (p = 0.003), PER2 (p = 0.002), PER3 (p < 0.001), CRY1 (p = 0.002), and CRY2 (p < 0.001). In CRC, 5 genes were downregulated: BMAL1 (p = 0.02), PER1 (p = 0.004), PER2 (p = 0.008), PER3 (p < 0.001), and CRY2 (p < 0.001). CSNK1E was upregulated in CRC (p = 0.02). Cyclin-D1 and WEE1 were both downregulated in CRLM and CRC. Related to clinicopathological factors, a significant correlation was found between low expression of CRY1 and female gender, and low PER3 expression and the number of CRLM. Our data demonstrate that the core clock is disrupted in CRLM and CRC tissue from the same patient. This disruption may be linked to altered cell-cycle dynamics and carcinogenesis.

Tashnizi AH, Jaberipour M, Razmkhah M, et al.
Tumour suppressive effects of WEE1 gene silencing in neuroblastomas.
J Cancer Res Ther. 2016 Jan-Mar; 12(1):221-7 [PubMed] Related Publications
AIM OF STUDY: WEE1, a member of serine/threonine protein kinase family is the master inhibitor of cyclin-dependent kinase 1 in cell cycle. Over-expression of WEE1 in glioblastomas (GBMs) and some other cancers has been shown. Here, we investigated the expression of WEE1 in 13 brain samples from GBM patients and two GBM cell lines. Further to that, we asked whether if knocking down WEE1 expression in the cell lines change tumor cells' reaction.
MATERIALS AND METHODS: All brain tumor samples were collected after confirmed pathological diagnosis. Western blotting was used to screen the expression of WEE1 and a panel of tumor markers. As a model of WEE1 gene silencing with small hairpin RNA (shRNA) technology in GBMs, A172, and U373GM cell lines were transfected with four WEE1 specific shRNAs. The growth characteristics of the cells and the expression of a panel of downstream genes were investigated after gene suppression.
RESULTS: All GBMs and both cell lines over-expressed WEE1. Transduction of the cell lines with different shRNAs suppressed WEE1 expression with different extent and pooling of four shRNAs together resulted in additive effect. Suppression of WEE1 not only repressed cellular growth but also changed the profile of gene expression of the cells. Quantitative real-time polymerase chain reaction showed also reduced expression of genes such as hypoxia-inducible factor-1, B-cell lymphoma-2, vascular endothelial growth factor, and p53 with crucial roles in tumor survival and invasiveness.
CONCLUSION: These results highlight the key role of WEE1 suppression to combat GBMs. Moreover, it showed beneficial possibilities of WEE1 suppression with different anticancer approaches for neurological malignancies.

Chang Q, Chandrashekhar M, Ketela T, et al.
Cytokinetic effects of Wee1 disruption in pancreatic cancer.
Cell Cycle. 2016; 15(4):593-604 [PubMed] Free Access to Full Article Related Publications
The Wee1 kinase, which is activated in response to DNA damage, regulates exit from G2 through inhibitory phosphorylation of Cdk1/Cdc2, and is an attractive drug target. However, recent work has highlighted effects of Cdk2 phosphorylation by Wee1 on movement through S-phase, suggesting the potential to sensitize to S-phase specific agents by Wee1 inhibitors. In this paper we applied multiparametric flow cytometry to patient-derived pancreatic cancer xenograft tumor cells to study the cell cycle perturbations of Wee1 disruption via the small molecule inhibitor MK-1775, and genetic knockdown. We find that in vitro treatment with MK-1775, and to a lesser degree, Wee1 RNA transcript knockdown, results in the striking appearance of S-phase cells prematurely entering into mitosis. This effect was not seen in vivo in any of the models tested. Here, although we noted an increase of S-phase cells expressing the damage response marker γH2AX, treatment with MK-1775 did not significantly sensitize cells to the cytidine analog gemcitabine. Treatment with MK-1775 did result in a transient but large increase in cells expressing the mitotic marker phosphorylated H3S10 that reached a peak 4 hours after treatment. This suggests a role for Wee1 regulating the progression of genomically unstable cancer cells through G2 in the absence of extrinsically-applied DNA damage. A single dose of 8Gy ionizing radiation resulted in the time-dependent accumulation of Cyclin A2 positive/phosphorylated H3S10 negative cells at the 4N position, which was abrogated by treatment with MK-1775. Consistent with these findings, a genome-scale pooled RNA interference screen revealed that toxic doses of MK-1775 are suppressed by CDK2 or Cyclin A2 knockdown. These findings support G2 exit as the more significant effect of Wee1 inhibition in pancreatic cancers.

Ghiasi N, Habibagahi M, Rosli R, et al.
Tumor suppressive effects of WEE1 gene silencing could not enhance immunopotentiation effects of CD80 and 4-1BBL co-stimulation in human T cells.
J Cancer Res Ther. 2015 Oct-Dec; 11(4):708-16 [PubMed] Related Publications
BACKGROUND: Activation of T cells against tumors by recruiting co-stimulatory molecules has been an attractive approach for cancer immunotherapy. Reports suggested that targeting different genes in tumors might also boost T cell-mediated tumor destruction.
AIMS: We investigated whether in vitro WEE1 gene silencing in MDA-MB-468 and MCF7 breast cancer cell lines could enhance immunopotentiating effects of CD80 and 4-1BBL co-stimulation in human T cells.
MATERIALS AND METHODS: WEE1 gene was specifically silenced in the cancer cells using shRNA technology. The co-stimulatory molecules were over-expressed on the surface of the cancer cells by recombinant non-replicative adenoviruses. The immune reaction of T cells in the co-culture with tumor cells was studied. IFN-g production was assessed by intracellular staining of T cells. To assess cytotoxic activity of CD8+ T cells, the CD107a mobilization-degranulation assay was performed. Expression of granzyme B, perforin and fasl were examined by real time PCR.
RESULTS: T cell dual co-stimulation led to a significant increase in the frequency of IFN-g producing cells and higher percentages of degranulation in CD8+ T cells. It also resulted in higher expression levels of the cytotoxicity-related genes. WEE1 gene silencing in the target cells alone however, could not produce significant immune reactivation in the cultured T cells. Likewise, the immune responses of T cells neither improved nor suppressed when dually co-stimulated PBMCs were exposed to the cancer cells with silenced WEE1.
CONCLUSIONS: In spite of antitumor effects of WEE1 silencing, combination of this approach with immune co-stimulation could not boost the reactivity of cultured T cells against the tested breast cancer cells.

Matheson CJ, Venkataraman S, Amani V, et al.
A WEE1 Inhibitor Analog of AZD1775 Maintains Synergy with Cisplatin and Demonstrates Reduced Single-Agent Cytotoxicity in Medulloblastoma Cells.
ACS Chem Biol. 2016; 11(4):921-30 [PubMed] Related Publications
The current treatment for medulloblastoma includes surgical resection, radiation, and cytotoxic chemotherapy. Although this approach has improved survival rates, the high doses of chemotherapy required for clinical efficacy often result in lasting neurocognitive defects and other adverse events. Therefore, the development of chemosensitizing agents that allow dose reductions of cytotoxic agents, limiting their adverse effects but maintaining their clinical efficacy, would be an attractive approach to treat medulloblastoma. We previously identified WEE1 kinase as a new molecular target for medulloblastoma from an integrated genomic analysis of gene expression and a kinome-wide siRNA screen of medulloblastoma cells and tissue. In addition, we demonstrated that WEE1 prevents DNA damage-induced cell death by cisplatin and that the WEE1 inhibitor AZD1775 displays synergistic activity with cisplatin. AZD1775 was developed as a WEE1 inhibitor from an initial hit from a high-throughput screen. However, given the lack of structure-activity data for AZD1775, we developed a small series of analogs to determine the requirements for WEE1 inhibition and further examine the effects of WEE1 inhibition in medulloblastoma. Interestingly, the compounds that inhibited WEE1 in the same nanomolar range as AZD1775 had significantly reduced single-agent cytotoxicity compared with AZD1775 and displayed synergistic activity with cisplatin in medulloblastoma cells. The potent cytotoxicity of AZD1775, unrelated to WEE1 inhibition, may result in dose-limiting toxicities and exacerbate adverse effects; therefore, WEE1 inhibitors that demonstrate low cytotoxicity could be dosed at higher concentrations to chemosensitize the tumor and potentiate the effect of DNA-damaging agents such as cisplatin.

Kibel AS, Ahn J, Isikbay M, et al.
Genetic variants in cell cycle control pathway confer susceptibility to aggressive prostate carcinoma.
Prostate. 2016; 76(5):479-90 [PubMed] Related Publications
BACKGROUND: Because a significant number of patients with prostate cancer (PCa) are diagnosed with disease unlikely to cause harm, genetic markers associated with clinically aggressive PCa have potential clinical utility. Since cell cycle checkpoint dysregulation is crucial for the development and progression of cancer, we tested the hypothesis that common germ-line variants within cell cycle genes were associated with aggressive PCa.
METHODS: Via a two-stage design, 364 common sequence variants in 88 genes were tested. The initial stage consisted of 258 aggressive PCa patients and 442 controls, and the second stage added 384 aggressive PCa Patients and 463 controls. European-American and African-American samples were analyzed separately. In the first stage, SNPs were typed by Illumina Goldengate assay while in the second stage SNPs were typed by Pyrosequencing assays. Genotype frequencies between cases and controls were compared using logistical regression analysis with additive, dominant and recessive models.
RESULTS: Eleven variants within 10 genes (CCNC, CCND3, CCNG1, CCNT2, CDK6, MDM2, SKP2, WEE1, YWHAB, YWHAH) in the European-American population and nine variants in 7 genes (CCNG1, CDK2, CDK5, MDM2, RB1, SMAD3, TERF2) in the African-American population were found to be associated with aggressive PCa using at least one model. Of particular interest, CCNC (rs3380812) was associated with risk in European-American cohorts from both institutions. CDK2 (rs1045435) and CDK5 (rs2069459) were associated with risk in the African-American cohorts from both institutions. Lastly, variants within MDM2 and CCNG1 were protective for aggressive PCa in both ethnic groups.
CONCLUSIONS: This study confirms that polymorphisms within cell cycle genes are associated with clinically aggressive PCa. Validation of these markers in additional populations is necessary, but these markers may help identify patients at risk for potentially lethal carcinoma.

Toledo CM, Ding Y, Hoellerbauer P, et al.
Genome-wide CRISPR-Cas9 Screens Reveal Loss of Redundancy between PKMYT1 and WEE1 in Glioblastoma Stem-like Cells.
Cell Rep. 2015; 13(11):2425-39 [PubMed] Free Access to Full Article Related Publications
To identify therapeutic targets for glioblastoma (GBM), we performed genome-wide CRISPR-Cas9 knockout (KO) screens in patient-derived GBM stem-like cells (GSCs) and human neural stem/progenitors (NSCs), non-neoplastic stem cell controls, for genes required for their in vitro growth. Surprisingly, the vast majority GSC-lethal hits were found outside of molecular networks commonly altered in GBM and GSCs (e.g., oncogenic drivers). In vitro and in vivo validation of GSC-specific targets revealed several strong hits, including the wee1-like kinase, PKMYT1/Myt1. Mechanistic studies demonstrated that PKMYT1 acts redundantly with WEE1 to inhibit cyclin B-CDK1 activity via CDK1-Y15 phosphorylation and to promote timely completion of mitosis in NSCs. However, in GSCs, this redundancy is lost, most likely as a result of oncogenic signaling, causing GBM-specific lethality.

Lu H, Chu Q, Xie G, et al.
Circadian gene expression predicts patient response to neoadjuvant chemoradiation therapy for rectal cancer.
Int J Clin Exp Pathol. 2015; 8(9):10985-94 [PubMed] Free Access to Full Article Related Publications
Preoperative neoadjuvant chemoradiation therapy may be useful in patients with operable rectal cancer, but treatment responses are variable. We examined whether expression levels of circadian clock genes could be used as biomarkers to predict treatment response. We retrospectively analyzed clinical data from 250 patients with rectal cancer, treated with neoadjuvant chemoradiation therapy in a single institute between 2011 and 2013. Gene expression analysis (RT-PCR) was performed in tissue samples from 20 patients showing pathological complete regression (pCR) and 20 showing non-pCR. The genes analyzed included six core clock genes (Clock, Per1, Per2, Cry1, Cry2 and Bmal1) and three downstream target genes (Wee1, Chk2 and c-Myc). Patient responses were analyzed through contrast-enhanced pelvic MRI and endorectal ultrasound, and verified by histological assessment. pCR was defined histologically as an absence of tumor cells. Among the 250 included patients, 70.8% showed regression of tumor size, and 18% showed pCR. Clock, Cry2 and Per2 expressions were significantly higher in the pCR group than in the non-pCR group (P<0.05), whereas Per1, Cry1 and Bmal1 expressions did not differ significantly between groups. Among the downstream genes involved in cell cycle regulation, c-Myc showed significantly higher expression in the pCR group (P<0.05), whereas Wee1 and Chk2 expression did not differ significantly between groups. Circadian genes are potential biomarkers for predicting whether a patient with rectal cancer would benefit from neoadjuvant chemoradiation therapy.

Pfister SX, Markkanen E, Jiang Y, et al.
Inhibiting WEE1 Selectively Kills Histone H3K36me3-Deficient Cancers by dNTP Starvation.
Cancer Cell. 2015; 28(5):557-68 [PubMed] Free Access to Full Article Related Publications
Histone H3K36 trimethylation (H3K36me3) is frequently lost in multiple cancer types, identifying it as an important therapeutic target. Here we identify a synthetic lethal interaction in which H3K36me3-deficient cancers are acutely sensitive to WEE1 inhibition. We show that RRM2, a ribonucleotide reductase subunit, is the target of this synthetic lethal interaction. RRM2 is regulated by two pathways here: first, H3K36me3 facilitates RRM2 expression through transcription initiation factor recruitment; second, WEE1 inhibition degrades RRM2 through untimely CDK activation. Therefore, WEE1 inhibition in H3K36me3-deficient cells results in RRM2 reduction, critical dNTP depletion, S-phase arrest, and apoptosis. Accordingly, this synthetic lethality is suppressed by increasing RRM2 expression or inhibiting RRM2 degradation. Finally, we demonstrate that WEE1 inhibitor AZD1775 regresses H3K36me3-deficient tumor xenografts.

Xu L, Ning H, Gu L, et al.
Tristetraprolin induces cell cycle arrest in breast tumor cells through targeting AP-1/c-Jun and NF-κB pathway.
Oncotarget. 2015; 6(39):41679-91 [PubMed] Free Access to Full Article Related Publications
The main characteristic of cancers, including breast cancer, is the ability of cancer cells to proliferate uncontrollably. However, the underlying mechanisms of cancer cell proliferation, especially those regulated by the RNA binding protein tristetraprolin (TTP), are not completely understood. In this study, we found that TTP inhibits cell proliferation in vitro and suppresses tumor growth in vivo through inducing cell cycle arrest at the S phase. Our studies demonstrate that TTP inhibits c-Jun expression through the C-terminal Zn finger and therefore increases Wee1 expression, a regulatory molecule which controls cell cycle transition from the S to the G2 phase. In contrast to the well-known function of TTP in regulating mRNA stability, TTP inhibits c-Jun expression at the level of transcription by selectively blocking NF-κB p65 nuclear translocation. Reconstitution of NF-κB p65 completely abolishes the inhibition of c-Jun transcription by TTP. Moreover, reconstitution of c-Jun in TTP-expressing breast tumor cells diminishes Wee1 overexpression and promotes cell proliferation. Our results indicate that TTP suppresses c-Jun expression that results in Wee1 induction which causes cell cycle arrest at the S phase and inhibition of cell proliferation. Our study provides a new pathway for TTP function as a tumor suppressor which could be targeted in tumor treatment.

Tamura K
Development of cell-cycle checkpoint therapy for solid tumors.
Jpn J Clin Oncol. 2015; 45(12):1097-102 [PubMed] Related Publications
Cellular proliferation is tightly controlled by several cell-cycle checkpoint proteins. In cancer, the genes encoding these proteins are often disrupted and cause unrestrained cancer growth. The proteins are over-expressed in many malignancies; thus, they are potential targets for anti-cancer therapies. These proteins include cyclin-dependent kinase, checkpoint kinase, WEE1 kinase, aurora kinase and polo-like kinase. Cyclin-dependent kinase inhibitors are the most advanced cell-cycle checkpoint therapeutics available. For instance, palbociclib (PD0332991) is a first-in-class, oral, highly selective inhibitor of CDK4/6 and, in combination with letrozole (Phase II; PALOMA-1) or with fulvestrant (Phase III; PALOMA-3), it has significantly prolonged progression-free survival, in patients with metastatic estrogen receptor-positive, HER2-negative breast cancer, in comparison with that observed in patients using letrozole, or fulvestrant alone, respectively. In this review, we provide an overview of the current compounds available for cell-cycle checkpoint protein-directed therapy for solid tumors.

Restelli V, Chilà R, Lupi M, et al.
Characterization of a mantle cell lymphoma cell line resistant to the Chk1 inhibitor PF-00477736.
Oncotarget. 2015; 6(35):37229-40 [PubMed] Free Access to Full Article Related Publications
Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoma characterized by the chromosomal translocation t(11;14) that leads to constitutive expression of cyclin D1, a master regulator of the G1-S phase. Chk1 inhibitors have been recently shown to be strongly effective as single agents in MCL. To investigate molecular mechanisms at the basis of Chk1 inhibitor activity, a MCL cell line resistant to the Chk1 inhibitor PF-00477736 (JEKO-1 R) was obtained and characterized. The JEKO-1 R cell line was cross resistant to another Chk1 inhibitor (AZD-7762) and to the Wee1 inhibitor MK-1775. It displayed a shorter doubling time than parental cell line, likely due to a faster S phase. Cyclin D1 expression levels were decreased in resistant cell line and its re-overexpression partially re-established PF-00477736 sensitivity. Gene expression profiling showed an enrichment in gene sets involved in pro-survival pathways in JEKO-1 R. Dasatinib treatment partly restored PF-00477736 sensitivity in resistant cells suggesting that the pharmacological interference of pro-survival pathways can overcome the resistance to Chk1 inhibitors. These data further corroborate the involvement of the t(11;14) in cellular sensitivity to Chk1 inhibitors, fostering the clinical testing of Chk1 inhibitors as single agents in MCL.

Shen JP, Srivas R, Gross A, et al.
Chemogenetic profiling identifies RAD17 as synthetically lethal with checkpoint kinase inhibition.
Oncotarget. 2015; 6(34):35755-69 [PubMed] Free Access to Full Article Related Publications
Chemical inhibitors of the checkpoint kinases have shown promise in the treatment of cancer, yet their clinical utility may be limited by a lack of molecular biomarkers to identify specific patients most likely to respond to therapy. To this end, we screened 112 known tumor suppressor genes for synthetic lethal interactions with inhibitors of the CHEK1 and CHEK2 checkpoint kinases. We identified eight interactions, including the Replication Factor C (RFC)-related protein RAD17. Clonogenic assays in RAD17 knockdown cell lines identified a substantial shift in sensitivity to checkpoint kinase inhibition (3.5-fold) as compared to RAD17 wild-type. Additional evidence for this interaction was found in a large-scale functional shRNA screen of over 100 genotyped cancer cell lines, in which CHEK1/2 mutant cell lines were unexpectedly sensitive to RAD17 knockdown. This interaction was widely conserved, as we found that RAD17 interacts strongly with checkpoint kinases in the budding yeast Saccharomyces cerevisiae. In the setting of RAD17 knockdown, CHEK1/2 inhibition was found to be synergistic with inhibition of WEE1, another pharmacologically relevant checkpoint kinase. Accumulation of the DNA damage marker γH2AX following chemical inhibition or transient knockdown of CHEK1, CHEK2 or WEE1 was magnified by knockdown of RAD17. Taken together, our data suggest that CHEK1 or WEE1 inhibitors are likely to have greater clinical efficacy in tumors with RAD17 loss-of-function.

Tanaka N, Patel AA, Wang J, et al.
Wee-1 Kinase Inhibition Sensitizes High-Risk HPV+ HNSCC to Apoptosis Accompanied by Downregulation of MCl-1 and XIAP Antiapoptotic Proteins.
Clin Cancer Res. 2015; 21(21):4831-44 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Although the majority of patients with HPV(+) oropharyngeal cancers have a favorable prognosis, there are some patients with tumors that are resistant to aggressive chemoradiotherapy with unusual patterns of locoregional and systemic recurrences. Therefore, more effective therapies are needed. In this study, we investigated the chemosensitizing efficacy of the selective Wee-1 kinase inhibitor, AZD-1775, in HPV(+) head and neck squamous cell carcinoma (HNSCC).
EXPERIMENTAL DESIGN: Clonogenic survival assays and an orthotopic mouse model of HPV(+) oral cancer were used to examine the in vitro and in vivo sensitivity of HPV(+) HNSCC cell lines to AZD-1775 in combination with cisplatin, respectively. Cell-cycle analysis, DNA damage (γH2AX), homologous recombination (HR), and apoptosis were examined to dissect molecular mechanisms.
RESULTS: We found that AZD-1775 displays single-agent activity and enhances the response of HPV(+) HNSCC cells to cisplatin both in vitro and in vivo. The sensitivity of the HPV(+) HNSCC cells to AZD-1775 alone or in combination with cisplatin was associated with G2 checkpoint abrogation, persistent DNA damage, and apoptosis induction. This finding of AZD-1775 increasing the sensitivity of HPV(+) HNSCC cells to cisplatin through apoptosis was not seen previously in the HPV(-) HNSCC cancer cells and is accompanied by a decreased expression of the antiapoptotic proteins, MCl-1and XIAP, which appear to be cleaved following AZD-1775 treatment.
CONCLUSIONS: AZD-1775 selectively sensitizes HPV(+) HNSCC cells and orthotopic oral xenografts to cisplatin through apoptosis and support the clinical investigation of AZD-1775 in combination with cisplatin particularly in patients with advanced and recurrent metastatic HPV(+) HNSCC tumors.

Mak JP, Man WY, Chow JP, et al.
Pharmacological inactivation of CHK1 and WEE1 induces mitotic catastrophe in nasopharyngeal carcinoma cells.
Oncotarget. 2015; 6(25):21074-84 [PubMed] Free Access to Full Article Related Publications
Nasopharyngeal carcinoma (NPC) is a rare but highly invasive cancer. As radiotherapy is the primary treatment for NPC, this offers a rationale to investigate if uncoupling the DNA damage responses can sensitize this cancer type. The G2 DNA damage checkpoint is controlled by a cascade of protein kinases: ATM/ATR, which phosphorylates CHK1/CHK2, which in turn phosphorylates WEE1. A number of small molecule inhibitors have been developed against these kinases as potential therapeutic agents. Here we demonstrated that compare to that in immortalized nasopharyngeal epithelial cells, ATR, CHK1, and WEE1 were overexpressed in NPC cell lines. Inhibitors of these kinases were unable to promote extensive mitotic catastrophe in ionizing radiation-treated NPC cells, indicating that they are not very effective radiosensitizer for this cancer. In the absence of prior irradiation, however, mitotic catastrophe could be induced with inhibitors against CHK1 (AZD7762) or WEE1 (MK-1775). NPC cells were more sensitive to WEE1 inactivation than nasopharyngeal epithelial cells. Targeting CHK1 and WEE1 together induced more extensive mitotic catastrophe than the individual components alone. Taken together, our results show that NPC cells depend on CHK1 and WEE1 activity for growth and that inhibitors of these kinases may serve as potential therapeutics for NPC.

Peng ZG, Yao YB, Yang J, et al.
Mangiferin induces cell cycle arrest at G2/M phase through ATR-Chk1 pathway in HL-60 leukemia cells.
Genet Mol Res. 2015; 14(2):4989-5002 [PubMed] Related Publications
This study aimed to determine the effect of mangiferin on the cell cycle in HL-60 leukemia cells and expression of the cell cycle-regulatory genes Wee1, Chk1 and CDC25C and to further investigate the molecular mechanisms of the antileukemic action of mangiferin. The inhibitory effect of mangiferin on HL-60 leukemia cell proliferation was determined by the MTT assay. The impact of mangiferin on the HL-60 cell cycle was evaluated by flow cytometry. After the cells were treated with different concentrations of mangiferin, the expression levels of Wee1, Chk1 and CDC25C mRNA were determined by RT-PCR, and Western blot was used to evaluate the expression levels of cdc25c, cyclin B1, and Akt proteins. The inhibition of HL-60 cell growth by mangiferin was dose- and time-dependent. After treatment for 24 h, cells in G2/M phase increased, and G2/M phase arrest appeared with increased mRNA expression of Wee1, Chk1 and CDC25C. Mangiferin inhibited Chk1 and cdc25c mRNA expression at high concentrations and induced Wee1 mRNA expression in a dose-dependent manner. It significantly inhibited ATR, Chk1, Wee1, Akt, and ERK1/2 phosphorylation but increased cdc2 and cyclin B1 phosphorylation. Furthermore, mangiferin reduced cdc25c, cyclin B1, and Akt protein levels while inducing Wee1 protein expression. It also antagonized the phosphorylation effect of vanadate on ATR, and the phosphorylation effect of EGF on Wee1. These findings indicated that mangiferin inhibits cell cycle progression through the ATR-Chk1 stress response DNA damage pathway, leading to cell cycle arrest at G2/M phase in leukemia cells.

Viedma-Rodríguez R, Ruiz Esparza-Garrido R, Baiza-Gutman LA, et al.
Involvement of multiple cellular pathways in regulating resistance to tamoxifen in BIK-suppressed MCF-7 cells.
Tumour Biol. 2015; 36(9):6991-7005 [PubMed] Related Publications
Majority of women with estrogen receptor (ER)-positive breast cancers initially respond to hormone therapies such as tamoxifen (TAM; antagonist of estrogen). However, many tumors eventually become resistant to TAM. Therefore, understanding the various cellular components involved in causing resistance to TAM is of paramount importance in designing novel entities for efficacious hormone therapy. Previously, we found that suppression of BIK gene expression induced TAM resistance in MCF-7 breast cancer cells. In order to understand the response of these cells to TAM and its association with resistance, a microarray analysis of gene expression was performed in the BIK-suppressed MCF-7 cells and compared it to the TAM-only-treated cells (controls). Several genes participating in various cellular pathways were identified. Molecules identified in the drug resistance pathway were 14-3-3z or YWHAZ, WEE1, PRKACA, NADK, and HSP90AA 1. Further, genes involved in cell cycle control, apoptosis, and cell proliferation were also found differentially expressed in these cells. Transcriptional and translational analysis of key molecules such as STAT2, AKT 3, and 14-3-3z revealed similar changes at the messenger RNA (mRNA) as well as at the protein level. Importantly, there was no cytotoxic effect of TAM on BIK-suppressed MCF-7 cells. Further, these cells were not arrested at the G0-G1 phase of the cell cycle although 30 % of BIK-suppressed cells were arrested at the G2 phase of the cycle on TAM treatment. Furthermore, we found a relevant interaction between 14-3-3z and WEE1, suggesting that the cytotoxic effect of TAM was prevented in BIK-suppressed cells because this interaction leads to transitory arrest in the G2 phase leading to the repair of damaged DNA and allowing the cells to proliferate.

Wang Z, Slipicevic A, Førsund M, et al.
Expression of CDK1(Tyr15), pCDK1(Thr161), Cyclin B1 (total) and pCyclin B1(Ser126) in vulvar squamous cell carcinoma and their relations with clinicopatological features and prognosis.
PLoS One. 2015; 10(4):e0121398 [PubMed] Free Access to Full Article Related Publications
Cyclin B1-CDK1 complex plays an important role in the regulation of cell cycle. Activation of Cyclin B1 and CDK1 and the formation of the complex in G2/M are under multiple regulations involving many regulators such as isoforms of 14-3-3 and CDC25 and Wee1. Abnormal expression of Cyclin B1 and CDK1 has been detected in various tumors. However, to our knowledge no previous study has investigated Cyclin B1 and CDK1 in vulvar cancer. Therefore, we evaluated the statuses of CDK1Tyr15, pCDK1Thr161, Cyclin B1 (total) and pCyclin B1Ser126 in 297 cases of vulvar squamous cell carcinomas by immunohistochemistry. Statistical analyses were performed to explore their clinicopathological and prognostic values. In at least 25% of tumor cases high expression of CDK1Tyr15, pCDK1Thr161, Cyclin B1 (total) and pCyclin B1Ser126 was observed, compared to the low levels in normal vulvar squamous epithelium. Elevated levels of CDK1Tyr15, pCDK1Thr161, Cyclin B1 (total) and pCyclin B1Ser126 were correlated with advanced tumor behaviors and aggressive features. Although CDK1Tyr15, pCDK1Thr161, Cyclin B1 (total) and pCyclin B1Ser126 could not be identified as prognostic factors, combinations of (pCDK1Thr161 C+N + 14-3-3σN), (pCDK1Thr161 C+N + 14-3-3ηC), (pCDK1Thr161 C+N + Wee1C) and (pCDK1Thr161 C+N + 14-3-3σN + 14-3-3ηC + Wee1C) were correlated with disease-specific survival (p = 0.036, p = 0.029, p = 0.042 and p = 0.007, respectively) in univariate analysis. The independent prognostic significance of (pCDK1Thr161 C+N + 14-3-3σN + 14-3-3ηC + Wee1C) was confirmed by multivariate analysis. In conclusion, CDK1Tyr15, pCDK1Thr161, Cyclin B1 (total) and pCyclin B1Ser126 may be involved in progression of vulvar squamous cell carcinoma. The combination of pCDK1Thr161, 14-3-3σ, 14-3-3η and Wee1 was a statistically independent prognostic factor.

Hatano K, Kumar B, Zhang Y, et al.
A functional screen identifies miRNAs that inhibit DNA repair and sensitize prostate cancer cells to ionizing radiation.
Nucleic Acids Res. 2015; 43(8):4075-86 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) have been implicated in DNA repair pathways through transcriptional responses to DNA damaging agents or through predicted miRNA regulation of DNA repair genes. We hypothesized that additional DNA damage regulating miRNAs could be identified by screening a library of 810 miRNA mimetics for the ability to alter cellular sensitivity to ionizing radiation (IR). A prostate cancer Metridia luciferase cell model was applied to examine the effects of individual miRNAs on IR sensitivity. A large percentage of miRNA mimetics were found to increase cellular sensitivity to IR, while a smaller percentage were protective. Two of the most potent IR sensitizing miRNAs, miR-890 and miR-744-3p, significantly delayed IR induced DNA damage repair. Both miRNAs inhibited the expression of multiple components of DNA damage response and DNA repair. miR-890 directly targeted MAD2L2, as well as WEE1 and XPC, where miR-744-3p directly targeted RAD23B. Knock-down of individual miR-890 targets by siRNA was not sufficient to ablate miR-890 radiosensitization, signifying that miR-890 functions by regulating multiple DNA repair genes. Intratumoral delivery of miR-890 mimetics prior to IR therapy significantly enhanced IR therapeutic efficacy. These results reveal novel miRNA regulation of DNA repair and identify miR-890 as a potent IR sensitizing agent.

Brockway S, Zeleznik-Le NJ
WEE1 is a validated target of the microRNA miR-17-92 cluster in leukemia.
Cancer Genet. 2015; 208(5):279-87 [PubMed] Free Access to Full Article Related Publications
MicroRNAs are short single-stranded RNAs that regulate target gene expression by binding to complementary sites in the 3' untranslated region (UTR) of their mRNA targets. The polycistronic miR-17-92 cluster, which encodes miR-17, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92a, was previously shown to be overexpressed in multiple types of cancer. In this study, target gene prediction algorithms were used to predict potential targets of the miR-17-92 cluster. WEE1, a kinase that inhibits cell cycle progression, was identified as a possible target of five of the six miRNAs in the cluster. Luciferase reporter assays were used to determine that miR-17, miR-20a, and miR-18a specifically target nucleotides 465-487 of the 3' UTR of WEE1, whereas miR-19a and miR-19b exert control on WEE1 by targeting nucleotides 1069-1091. A negative correlation was determined between endogenous miR-17 or miR-19a expression and endogenous WEE1 protein expression in the same panel of cell lines. We conclude that WEE1 is a valid target of the miR-17-92 cluster in leukemia.

Mei Z, Su T, Ye J, et al.
The miR-15 family enhances the radiosensitivity of breast cancer cells by targeting G2 checkpoints.
Radiat Res. 2015; 183(2):196-207 [PubMed] Related Publications
Enhancing radiosensitivity is an important area of investigation for improving breast cancer therapy outcomes. The aim of this study was to assess the role of the miR-15 family in the radiosensitivity of breast cancer cells. MicroRNAs (miRNAs) encoded by the miR-15 cluster are known to induce G1 arrest and apoptosis by targeting G1 checkpoints and the anti-apoptotic B cell lymphoma 2 (BCL-2) gene. However, the effect of the miR-15 family on G2/M arrest and radiosensitivity remains poorly understood. In the current study, cells transfected with miR-15a/15b/16 mimic or inhibitor were irradiated and examined by: clonogenic assays, phosphorylated H2AX assay, flow cytometry, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), real-time PCR and Western blot. Real-time PCR was also used to monitor time-dependent changes of miR-15a/15b/16 expression after irradiation. A putative target site for miR-15a/15b/16 within the Chk1 and Wee1 3' UTRs was confirmed using luciferase reporter assays. Additionally, siRNA was used to validate the effect of Chk1 and Wee1 on radiosensitivity in breast cancer cells. In our study, we investigated the effects of radiation on the miR-15 family and found a time-dependent change in the expression of miR-15a/15b/16 in breast cancer cells postirradiation, as well as an increase in miR-15 family-mediated sensitization of breast cancer cells to radiation. The increase in radiosensitivity induced by the miR-15 family was associated with persistent unrepaired DNA damage, abrogation of radiation-induced G2 arrest and suppressed cell proliferation, and appear to involve both the checkpoint kinase 1 (Chk1) and Wee1. In addition, we found that inhibition of the miR-15 family could not induce cell resistance to radiation. These findings suggest that the expression of the miR-15 family contributes to increased radiosensitivity of breast cancer cells by influencing G2/M checkpoint proteins.

Osman AA, Monroe MM, Ortega Alves MV, et al.
Wee-1 kinase inhibition overcomes cisplatin resistance associated with high-risk TP53 mutations in head and neck cancer through mitotic arrest followed by senescence.
Mol Cancer Ther. 2015; 14(2):608-19 [PubMed] Free Access to Full Article Related Publications
Although cisplatin has played a role in "standard-of-care" multimodality therapy for patients with advanced squamous cell carcinoma of the head and neck (HNSCC), the rate of treatment failure remains particularly high for patients receiving cisplatin whose tumors have mutations in the TP53 gene. We found that cisplatin treatment of HNSCC cells with mutant TP53 leads to arrest of cells in the G2 phase of the cell cycle, leading us to hypothesize that the wee-1 kinase inhibitor MK-1775 would abrogate the cisplatin-induced G2 block and thereby sensitize isogenic HNSCC cells with mutant TP53 or lacking p53 expression to cisplatin. We tested this hypothesis using clonogenic survival assays, flow cytometry, and in vivo tumor growth delay experiments with an orthotopic nude mouse model of oral tongue cancer. We also used a novel TP53 mutation classification scheme to identify which TP53 mutations are associated with limited tumor responses to cisplatin treatment. Clonogenic survival analyses indicate that nanomolar concentration of MK-1775 sensitizes HNSCC cells with high-risk mutant p53 to cisplatin. Consistent with its ability to chemosensitize, MK-1775 abrogated the cisplatin-induced G2 block in p53-defective cells leading to mitotic arrest associated with a senescence-like phenotype. Furthermore, MK-1775 enhanced the efficacy of cisplatin in vivo in tumors harboring TP53 mutations. These results indicate that HNSCC cells expressing high-risk p53 mutations are significantly sensitized to cisplatin therapy by the selective wee-1 kinase inhibitor, supporting the clinical evaluation of MK-1775 in combination with cisplatin for the treatment of patients with TP53 mutant HNSCC.

Chilà R, Basana A, Lupi M, et al.
Combined inhibition of Chk1 and Wee1 as a new therapeutic strategy for mantle cell lymphoma.
Oncotarget. 2015; 6(5):3394-408 [PubMed] Free Access to Full Article Related Publications
Mantle cell lymphoma (MCL) is an aggressive, incurable disease, characterized by a deregulated cell cycle. Chk1 and Wee1 are main regulators of cell cycle progression and recent data on solid tumors suggest that simultaneous inhibition of these proteins has a strong synergistic cytotoxic effect. The effects of a Chk1 inhibitor (PF-00477736) and a Wee1 inhibitor (MK-1775) have been herein investigated in a large panel of mature B-cell lymphoma cell lines. We found that MCL cells were the most sensitive to the Chk1 inhibitor PF-00477736 and Wee1 inhibitor MK-1775 as single agents. Possible involvement of the translocation t(11;14) in Chk1 inhibitor sensitivity was hypothesized. The combined inhibition of Chk1 and Wee1 was strongly synergistic in MCL cells, leading to deregulation of the cell cycle, with increased activity of CDK2 and CDK1, and activation of apoptosis. In vivo treatment with the drug combination of mice bearing JeKo-1 xenografts (MCL) had a marked antitumor effect with tumor regressions observed at non-toxic doses (best T/C%=0.54%). Gene expression profiling suggested effect on genes involved in apoptosis. The strong synergism observed by combining Chk1 and Wee1 inhibitors in preclinical models of MCL provides the rationale for testing this combination in the clinical setting.

Chang KE, Wei BR, Madigan JP, et al.
The protein phosphatase 2A inhibitor LB100 sensitizes ovarian carcinoma cells to cisplatin-mediated cytotoxicity.
Mol Cancer Ther. 2015; 14(1):90-100 [PubMed] Free Access to Full Article Related Publications
Despite early positive response to platinum-based chemotherapy, the majority of ovarian carcinomas develop resistance and progress to fatal disease. Protein phosphatase 2A (PP2A) is a ubiquitous phosphatase involved in the regulation of DNA-damage response (DDR) and cell-cycle checkpoint pathways. Recent studies have shown that LB100, a small-molecule inhibitor of PP2A, sensitizes cancer cells to radiation-mediated DNA damage. We hypothesized that LB100 could sensitize ovarian cancer cells to cisplatin treatment. We performed in vitro studies in SKOV-3, OVCAR-8, and PEO1, -4, and -6 ovarian cancer lines to assess cytotoxicity potentiation, cell-death mechanism(s), cell-cycle regulation, and DDR signaling. In vivo studies were conducted in an intraperitoneal metastatic mouse model using SKOV-3/f-Luc cells. LB100 sensitized ovarian carcinoma lines to cisplatin-mediated cell death. Sensitization via LB100 was mediated by abrogation of cell-cycle arrest induced by cisplatin. Loss of the cisplatin-induced checkpoint correlated with decreased Wee1 expression, increased cdc2 activation, and increased mitotic entry (p-histone H3). LB100 also induced constitutive hyperphosphorylation of DDR proteins (BRCA1, Chk2, and γH2AX), altered the chronology and persistence of JNK activation, and modulated the expression of 14-3-3 binding sites. In vivo, cisplatin sensitization via LB100 significantly enhanced tumor growth inhibition and prevented disease progression after treatment cessation. Our results suggest that LB100 sensitizes ovarian cancer cells to cisplatin in vitro and in vivo by modulation of the DDR pathway and cell-cycle checkpoint abrogation.

Zhou L, Zhang Y, Chen S, et al.
A regimen combining the Wee1 inhibitor AZD1775 with HDAC inhibitors targets human acute myeloid leukemia cells harboring various genetic mutations.
Leukemia. 2015; 29(4):807-18 [PubMed] Free Access to Full Article Related Publications
AZD1775 targets the cell cycle checkpoint kinase Wee1 and potentiates genotoxic agent cytotoxicity through p53-dependent or -independent mechanisms. Here, we report that AZD1775 interacted synergistically with histone deacetylase inhibitors (HDACIs, for example, Vorinostat), which interrupt the DNA damage response, to kill p53-wild type (wt) or -deficient as well as FLT3-ITD leukemia cells in association with pronounced Wee1 inhibition and diminished cdc2/Cdk1 Y15 phosphorylation. Similarly, Wee1 shRNA knockdown significantly sensitized cells to HDACIs. Although AZD1775 induced Chk1 activation, reflected by markedly increased Chk1 S296/S317/S345 phosphorylation leading to inhibitory T14 phosphorylation of cdc2/Cdk1, these compensatory responses were sharply abrogated by HDACIs. This was accompanied by premature mitotic entry, multiple mitotic abnormalities and accumulation of early S-phase cells displaying increased newly replicated DNA, culminating in robust DNA damage and apoptosis. The regimen was active against patient-derived acute myelogenous leukemia (AML) cells harboring either wt or mutant p53 and various next-generation sequencing-defined mutations. Primitive CD34(+)/CD123(+)/CD38(-) populations enriched for leukemia-initiating progenitors, but not normal CD34(+) hematopoietic cells, were highly susceptible to this regimen. Finally, combining AZD1775 with Vorinostat in AML murine xenografts significantly reduced tumor burden and prolonged animal survival. A strategy combining Wee1 with HDACI inhibition warrants further investigation in AML with poor prognostic genetic aberrations.

Quan J, Adelmant G, Marto JA, et al.
The chromatin remodeling factor CHD5 is a transcriptional repressor of WEE1.
PLoS One. 2014; 9(9):e108066 [PubMed] Free Access to Full Article Related Publications
Loss of the chromatin remodeling ATPase CHD5 has been linked to the progression of neuroblastoma tumors, yet the underlying mechanisms behind the tumor suppressor role of CHD5 are unknown. In this study, we purified the human CHD5 complex and found that CHD5 is a component of the full NuRD transcriptional repressor complex, which also contains methyl-CpG binding proteins and histone deacetylases. The CHD5/NuRD complex appears mutually exclusive with the related CHD4/NuRD complex as overexpression of CHD5 results in loss of the CHD4 protein in cells. Following a search for genes that are regulated by CHD5 in neuroblastoma cells, we found that CHD5 binds to and represses the G2/M checkpoint gene WEE1. Reintroduction of CHD5 into neuroblastoma cells represses WEE1 expression, demonstrating that CHD5 can function as a repressor in cells. A catalytically inactive mutant version of CHD5 is able to associate with a NuRD cofactor but fails to repress transcription. Our study shows that CHD5 is a NuRD-associated transcriptional repressor and identifies WEE1 as one of the CHD5-regulated genes that may link CHD5 to tumor suppression.

Moser R, Xu C, Kao M, et al.
Functional kinomics identifies candidate therapeutic targets in head and neck cancer.
Clin Cancer Res. 2014; 20(16):4274-88 [PubMed] Free Access to Full Article Related Publications
PURPOSE: To identify novel therapeutic drug targets for p53-mutant head and neck squamous cell carcinoma (HNSCC).
EXPERIMENTAL DESIGN: RNAi kinome viability screens were performed on HNSCC cells, including autologous pairs from primary tumor and recurrent/metastatic lesions, and in parallel on murine squamous cell carcinoma (MSCC) cells derived from tumors of inbred mice bearing germline mutations in Trp53, and p53 regulatory genes: Atm, Prkdc, and p19(Arf). Cross-species analysis of cell lines stratified by p53 mutational status and metastatic phenotype was used to select 38 kinase targets. Both primary and secondary RNAi validation assays were performed on additional HNSCC cell lines to credential these kinase targets using multiple phenotypic endpoints. Kinase targets were also examined via chemical inhibition using a panel of kinase inhibitors. A preclinical study was conducted on the WEE1 kinase inhibitor, MK-1775.
RESULTS: Our functional kinomics approach identified novel survival kinases in HNSCC involved in G2-M cell-cycle checkpoint, SFK, PI3K, and FAK pathways. RNAi-mediated knockdown and chemical inhibition of the WEE1 kinase with a specific inhibitor, MK-1775, had a significant effect on both viability and apoptosis. Sensitivity to the MK-1775 kinase inhibitor is in part determined by p53 mutational status, and due to unscheduled mitotic entry. MK-1775 displays single-agent activity and potentiates the efficacy of cisplatin in a p53-mutant HNSCC xenograft model.
CONCLUSIONS: WEE1 kinase is a potential therapeutic drug target for HNSCC. This study supports the application of a functional kinomics strategy to identify novel therapeutic targets for cancer.

Kogiso T, Nagahara H, Hashimoto E, et al.
Efficient induction of apoptosis by wee1 kinase inhibition in hepatocellular carcinoma cells.
PLoS One. 2014; 9(6):e100495 [PubMed] Free Access to Full Article Related Publications
Transforming growth factor-β1 (TGF-β1) potently inhibits human hepatocellular carcinoma (HCC) cell growth. Here we demonstrated that TGF-β1-induced apoptosis is mediated by decreased phosphorylation of cdc2 at Tyr15 accompanied by down-regulation of Wee1 kinase expression. As expected from these results, a Wee1 kinase inhibitor efficiently induced apoptosis in HCC cells in the absence of TGF-β1 treatment. In surgically resected samples, Wee1 kinase was expressed in moderately to poorly differentiated HCC, whereas no Wee1 kinase expression was observed in non-cancerous tissue, including cirrhotic tissue. Our results suggest that Wee1 kinase inhibitors may be a practical novel therapeutic option against advanced HCC.

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