Expression Of Wee1 Research Articles

Abstract 3163: The role of early response genes (ERG’s) as a biomarker of response to Wee1 targeted therapies

Abstract Introduction: WEE1 kinase is a key component in maintaining the G2/M cell cycle checkpoint for pre-mitotic DNA repair, and is overexpressed in several cancer types. Novel therapeutics are currently being developed to target WEE1 kinase in cancer, however, to date no predictive biomarkers have been approved to aid patient stratification and clinical trial design. To address this, we employed a siRNA screening to identify tumour suppressor genes (TSGs) whose loss mediates sensitivity to WEE1 inhibition. Experimental procedures: U2OS cells were reverse transfected with a customised siRNA library containing 3 independent siRNAs targeting 178 tumour suppressor genes and 24 hours later treated with either DMSO control or MK-1775 (Wee1 Kinase Inhibitor). Cell viability was measured using a cell titer-glo luminescent Cell Viability Assay 72 hours post-treatment. Hits were selected based on robust z-score analysis. Those genes with 2 or more targeted siRNAs demonstrating a robust z-score of ±1 median absolute deviation (MAD) were taken forward for validation studies. Sensitive hits were selected on a z-score of <-1 and resistant hits were selected on a z-score of >1. siRNA knockdown of WEE1 was performed in multiple human cancer cell lines and confirmed by western blotting and RT-q-PCR. Basal expression levels of phosphorylated WEE1, total WEE1, FOS and JUNB were assessed by western blotting. Results: Consistent with previously published findings, the siRNA screen demonstrated that loss of BRCA2 conferred increased sensitivity to WEE1 inhibition (Aarts et al. 2015). The siRNA screen also identified an additional 12 TSGs whose loss mediated sensitivity and 14 TSGs whose loss mediated resistance to WEE1 kinase inhibition. Interestingly, we found that loss of two early response genes, FOS and JUNB conferred resistance to WEE1 inhibition. FOS and JUNB interact to form the AP1 heterodimer, and previous published work has demonstrated the presence of an AP1 binding motif on the WEE1 promoter (Kawasaki et al. 2003). Using publically available gene expression data (TCGA) we have shown a significant correlation between expression of WEE1 with FOS and JUNB in multiple cancer types. Conclusions: Using a TSG siRNA screen, we have identified that loss of JUNB and FOS confers resistance to the WEE1 inhibitor MK1775. Future studies will investigate the mechanisms by which the loss of these genes affects response to WEE1 inhibition, and will also investigate the utility of these genes as predictive biomarkers for response to WEE1 inhibition in clinical samples, thereby aiding patient stratification. Citation Format: Victoria L. Dunne, Niamh McGivern, Kienan I. Savage, Nuala McCabe, Richard Kennedy. The role of early response genes (ERG’s) as a biomarker of response to Wee1 targeted therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3163.

Abstract 4420: Small-molecule inhibition of Wee1 kinase by AZD1775 selectively sensitizes human papilloma virus (HPV)-associated cervical cancer to DNA-damaging therapies

Abstract Objective: Wee1 regulate G2-M checkpoint of cell-cycle Inhibition of Wee1 promotes cell mitosis without DNA repair in cases with TP53 deficiency Since human papillomavirus (HPV) E6 involves the inactivation of p53, we aimed to evaluate effects of Wee1 inhibitor on cervical cancer. Material and Methods: Expression level of Wee1 in cervical cancer was evaluated using Oncomine Cervical cancer cell lines, Caski (HPV16+), SiHa (HPV16+) and C33A (HPV-, P53 mut) and LNCap (HPV-, P53 wt, prostate cancer) were used. After exposure to either Wee1 inhibitor (AZD1775), cisplatin, or both, cell surviving rate was evaluated by MTT assay and expression levels of Wee1 and cell cycle related proteins were evaluated by western blotting cell cycle status in cell lines were observed by flow cytometry. Results: High expression of Wee1 in cervical cancer was clinically observed among ten cancer species. Stepwise treatment of AZD1775 promoted significant cell death induction, compared with exposure to cisplatin alone in HPV-positive cells (Caski and Siha); however no effect on cell death in HPV-negative cells (C33A and LNCap). In addition, expression level of pCDC2 was reduced after exposure to AZD1775, indicating induction of cell mitosis without DNA repair. Conclusion: Our results indicate the therapeutic potential of cervical cancer treatment by Wee1 inhibition. Synergistic effect of Wee1 inhibition with conventional treatments (CCRT or chemotherapy) may be a new strategy to improve the prognosis in cervical cancer. Citation Format: Osamu Kobayashi, Yuji Ikeda, Yuki Okuma, Nobuki Hayashi, Takahiro Nakajima, Mikiko Asai-Sato, Kei Kawana. Small-molecule inhibition of Wee1 kinase by AZD1775 selectively sensitizes human papilloma virus (HPV)-associated cervical cancer to DNA-damaging therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4420.

LncRNA SNHG3 regulates laryngeal carcinoma proliferation and migration by modulating the miR-384/WEE1 axis

LncRNA SNHG3 (SNHG3) is involved in tumor development and progression, but little is known about how SNHG3 functions in laryngeal carcinoma (LC). Real time-PCR (RT-PCR) was used to estimate the expression of SNHG3 in LC tissues and cell lines TU212, TU686, and Hep-2. Cell viability, migration, and invasion were evaluated. Our results showed increased SNHG3 in LC tissues and cell lines. Loss of function of SNHG3 reduced cell viability, migration, and invasion of TU212 and TU686 cells. Western blot analyses demonstrated that the protein levels of MMP2 and MMP9 decreased after SNHG3 silencing. Additionally, bioinformatics software predicted that SNHG3 could sponge miR-384 at the 3′-UTR with complementary binding sites, which was validated by a dual-luciferase reporter assay. RT-PCR analysis revealed that knockdown of SNHG3 upregulated miR-384 expression and that overexpression of miR-384 decreased SNHG3. Furthermore, a dual-luciferase reporter assay showed that miR-384 could bind to the 3′-UTR of WEE1, and inhibition of miR-384 markedly increased WEE1 expression. The mRNA and protein levels of WEE1 were downregulated upon deletion of SNGH3. Suppression of WEE1 partly abolished the tumorigenic migration and invasion potential of the miR-384 inhibitor in migration and invasion. Inhibition of miR-384 partially reversed the biological activities of SNHG3 in TU212 and TU686 cells. Collectively, our results indicate that SNHG3 regulated LC cell migration and invasion via the miR-384/WEE1 axis.

Expression of Arabidopsis WEE1 in tobacco induces unexpected morphological and developmental changes

WEE1 regulates the cell cycle by inactivating cyclin dependent protein kinases (CDKs) via phosphorylation. In yeast and animal cells, CDC25 phosphatase dephosphorylates the CDK releasing cells into mitosis, but in plants, its role is less clear. Expression of fission yeast CDC25 (Spcdc25) in tobacco results in small cell size, premature flowering and increased shoot morphogenetic capacity in culture. When Arath;WEE1 is over-expressed in Arabidopsis, root apical meristem cell size increases, and morphogenetic capacity of cultured hypocotyls is reduced. However expression of Arath;WEE1 in tobacco plants resulted in precocious flowering and increased shoot morphogenesis of stem explants, and in BY2 cultures cell size was reduced. This phenotype is similar to expression of Spcdc25 and is consistent with a dominant negative effect on WEE1 action. Consistent with this putative mechanism, WEE1 protein levels fell and CDKB levels rose prematurely, coinciding with early mitosis. The phenotype is not due to sense-mediated silencing of WEE1, as overall levels of WEE1 transcript were not reduced in BY2 lines expressing Arath;WEE1. However the pattern of native WEE1 transcript accumulation through the cell cycle was altered by Arath;WEE1 expression, suggesting feedback inhibition of native WEE1 transcription.

Targeting the WEE1 kinase strengthens the antitumor activity of imatinib via promoting KIT autophagic degradation in gastrointestinal stromal tumors.

Activating mutation of KIT or PDGFRA is the primary molecular mechanism for gastrointestinal stromal tumors (GISTs). Although imatinib has a revolutionary effect on GIST therapeutics, the benefits are not durable. Increasing reports have demonstrated that cell cycle checkpoint plays critical roles in GIST. Here, we explore the role of WEE1 kinase in GIST progression. Oncomine public database, western blotting, and immunohistochemistry were used to analyze WEE1 expression in GISTs. Using MTT assays, colony formation analysis, and flow cytometry, we examined the role of WEE1 in GIST cells and the antitumor activity of the inhibitor MK1775 alone, or in combination with imatinib. Cycloheximide chase assay and pharmacological inhibition of autophagy and proteasome pathway were performed to analyze KIT expression. Additionally, autophagic markers Beclin1 and LC3B were detected by western blotting. Upregulated WEE1 expression was observed in GIST tissues and correlated with tumor size, mitotic count, and risk grade. Inhibition of WEE1 significantly suppressed GIST cell proliferation, induced apoptosis and cell cycle arrest. Imatinib and MK1775 co-treatment markedly enhanced the antitumor activity. Targeting WEE1 decreased the expression of KIT expression. Moreover, WEE1 stabilized KIT protein and KIT reduction observed upon WEE1 inhibition could be reversed by pharmacological inhibition of autophagy, but not proteasome pathway. WEE1 inhibition also increased Beclin1 expression and LC3B II/I ratio in GIST cells. Our data suggest that WEE1 plays a pivotal role in GIST proliferation. WEE1 inhibition could promote KIT autophagic degradation and, therefore, targeting WEE1 might represent a novel strategy for GIST therapies.

EUDARIO/ENGOTov-48: A European multicenter randomised phase II trial on the combination of the HSP90 inhibitor ganetespib with carboplatin followed by maintenance treatment with niraparib (+/- ganetespib) compared to platinum-based combination-chemotherapy followed by niraparib in relapsed platinum-sensitive ovarian cancer patients.

TPS5605 Background: Carboplatin (C) mainly acts by forming interstrand crosslinks (ICL) within the DNA double helix, which can only be removed by the Fanconi Anemia (FA) pathway. HSP90 inhibitors destabilise a number of HSP90 client proteins, such as those governing the FA DNA repair pathway and the G2/M checkpoint (e.g. Chk1 and Wee1). Kramer et al. (Cell Death Differ, 2017) showed that the HSP90 inhibitor Ganetespib (G) virtually eliminates a functional FA DNA repair complex, therewith preventing the repair of DNA ICL in vitro and vivo. In parallel, G abrogated Chk1 and Wee1 expression and circumvented a G2/M arrest. Consequently, cells with unrepaired DNA damage rushed into mitosis, which resulted in massive tumour cell death. Furthermore, HSP90 inhibition has been shown to reduce the amount of BRCA1 in the cell therewith broadening sensitivity towards PARPi and preventing acquired PARP resistance. Our trial approach is tested in ovarian carcinomas with a mutant p53 background. EUDARIO (EUDRACT 017-004058-40) is funded by the European Commission (FP7 project GANNET53). Methods: Eligible patients have relapsed platinum-sensitive ovarian cancer, no limits in prior lines, high-grade (but clear cell) histology or carcinosarcoma, disease measurable or evaluable according to RECIST 1.1. Patients are randomised into 3 treatment arms (1:1:1), a) control arm: C+Gemcitabine or C+Paclitaxel (q3w, 6 cycles, investigator`s choice) followed by Niraparib, b+c) 2 experimental arms: C (AUC5, d1) + G (150mg/m2, d1) q3w 6 cycles followed by either Niraparib alone (arm b) or by Niraparib+G (arm c; G at 100mg/m2 weekly, limited to 9 months). Niraparib (200/300mg/day) is given in case of SD, PR or CR after platinum-based treatment until disease progression. The main analysis will combine both experimental arms b+c and jointly compare them against arm a using log-rank test. Primary endpoint is PFS, secondary endpoints are PFS2, TFST, TSST, safety, ORR, PRO, OS. The first patient was dosed in January 2019. Clinical trial information: NCT03783949.

Loss of miR-155 upregulates WEE1 in metastatic melanoma.

Significant advances have been made in the treatment of melanoma by targeting key cellular pathways, but additional targets are needed as many patients do not respond or relapse with resistant disease. MicroRNA-155 (MiR-155) has previously been shown to regulate melanoma cell growth and acts as a tumor suppressor. We tested a clinical population of melanoma tumors for miR-155 expression, and find that expression is low in most patients, although not predictive of outcome. We identified the protein kinase WEE1 as a novel target of miR-155. A mouse model of experimental metastasis finds that both increased expression of miR-155 and silencing of WEE1 lead to decreased metastases. Loss of miR-155 and increased expression of WEE1 may contribute to the metastatic phenotype in patients with melanoma.

Long noncoding RNA DLX6-AS1 promotes liver cancer by increasing the expression of WEE1 via targeting miR-424-5p.

Long noncoding RNAs (lncRNAs) played an important role in tumorigenesis and development of hepatocellular carcinoma (HCC). In this study, we first demonstrated that lncRNA DLX6 antisense RNA 1 (DLX6‐AS1) was upregulated in cancer tissues and cells lines compared with normal adjacent and cell line. Knock‐down DLX6‐AS1 by transfection with small interfering RNA (siRNA) suppressed cell proliferation, migration, and invasion of HCC cells. Cell cycle analysis showed that cells transfected with siRNA were arrested in G0/G1 phase. Then, we performed dual‐luciferase reporter assay and RNA immunoprecipitation (RIP) assay to show that DLX6‐AS1 could bind with miR‐424‐5p. And cotransfection inhibitor of miR‐424‐5p with siRNA of DLX6‐AS1 could abolish the inhibitory effect of siRNA of DLX6‐AS1 on cell proliferation, migration, and invasion. Moreover, we further demonstrated that the oncogene WEE1 G2 checkpoint kinase (WEE1) was the target of miR‐424‐5p and expression levels of WEE1 were positive correlation with that of DLX6‐AS1. Taken together, these results suggested that upregulated DLX6‐AS1 promoted cell proliferation, migration, and invasion of HCC through increasing expression of WEE1 via targeting miR‐424‐5p.

Leveraging Transcriptional Dynamics to Improve BRAF Inhibitor Responses in Melanoma

Melanoma is known to be a heterogeneous tumor, but the impact of this heterogeneity upon therapeutic response is not well understood. In the current study, we used single cell mRNA analysis and our Single Cell HETerogeneity (SinCHET) platform to define the transcriptional diversity of melanoma and its dynamic response to both BRAF inhibitor therapy and treatment holidays. Our analyses showed melanoma cell lines and patient specimens to be composed of >3 co-existent, transcriptionally distinct states. Among these, State #1 had increased expression of cyclin D1, ERBB3, STAT3/5, MITF and I²-catenin and lower expression of c-JUN and RTKs such as Axl and EGFR. State #2 was characterized by higher expression of ERBB3, Axl and the transcription factor c-JUN. State #3 was characterized by high Axl, c-JUN, E2F1, WEE1, c-MET and EGFR expression and lower expression of MITF, ERBB3 and SMAD9. The cell state composition was dynamically regulated in response to BRAF inhibitor therapy, with State #1 declining and States #2 and #3 increasing in response to drug. The percentage of cells in State #1 recovered following a drug holiday, allowing for a successful therapy rechallenge. Other melanomas that lacked State #1 had varying degrees of intrinsic drug resistance and were not amenable to rechallenge. We next leveraged the differences in fitness between the different transcriptional states in the absence and presence of drug to develop a mathematical model that optimized therapy schedules to retain the drug sensitive population. In vivo validation of the mathematical model demonstrated that the personalized adaptive dosing schedules were better at suppressing tumor growth than either continuous or fixed intermittent BRAF inhibitor schedules. Together our studies provide the first preclinical evidence that transcriptional heterogeneity at the single cell level predicts for the initial sensitivity to BRAF inhibitor therapy. We further demonstrate that manipulating transcriptional heterogeneity through personalized adaptive therapy schedules that can delay the time to resistance. Funding Statement: Supported by SPORE grant P50 CA168536, R21 CA198550, R21 CA216756 (to KSMS) K99 CA226679 (to IS), Moffitt Cancer Center PSOC, U54 CA193489 (EK & AA) and the Cancer Center Support Grant P30 CA076292 from the NIH (NCI/NIH). We also acknowledge the support Miami Center for AIDS Research (CFAR) at the University of Miami Miller School of Medicine funded by P30AI073961. Declaration of Interests: We have no competing interest to declare. Ethics Approval Statement: All animal experiments were carried out in compliance with ethical regulations and protocols approved by the University of South Florida Institutional Animal Care and Use Committee.

BRD4 Inhibitor AZD5153 Suppresses the Proliferation of Colorectal Cancer Cells and Sensitizes the Anticancer Effect of PARP Inhibitor.

Background: Bromodomain-containing protein 4(BRD4) is reported to play a vital role in the development of numerous malignant diseases, which is considered as a promising target for cancer therapy. AZD5153, a novel specific BRD4 inhibitor, showed potent anticancer effects in several cancer types, but its therapeutic potential has not been fully evaluated in colorectal cancer cells.Objective: We sought to evaluate the therapeutic potential of BRD4 inhibition of by AZD5153 and its combined anticancer cancer effect with PARP inhibitor BMN673 in vitro and in vivo in colorectal cancer.Methods: We analyzed The Cancer Genome Atlas (TCGA) database to investigate BRD4 expression in colorectal cancer patient. Clonogenic assays 、MTT assays and PI/Annexin V staining were used to determine the effect of AZD5153 and BMN673 and combination therapy on cell viability and apoptosis induction. Western blotting was applied to detect relevant molecules changes. Propidium iodide staining was performed to examine cell cycle distributions after monotherapy or combination therapy. Nude mice xenograft model was generated to confirm the therapeutic effect of AZD5153 and BMN673 combination in vivo, and IHC staining was used to detect the expression level of BRD4 and related markers in colorectal patient and xenograft.Results: Analysis of TCGA database indicated that BRD4 was overexpressed in colorectal cancer patient. The clonogenic and MTT assays and PI/Annexin V staining demonstrated that AZD5153 significantly suppressed cell proliferation and induced apoptosis in colorectal cancer cells HCT116 and LoVo. Western blotting showed that AZD5153 inhibited the expression of c-Myc and increased expression of the apoptosis markers, cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP), besides, we found that BRD4 knockdown could also inhibited cell proliferation and induced cell apoptosis. Moreover, AZD5153 inhibited the expression of Wee1 and impaired G2M cell cycle checkpoint, thus sensitized the anticancer effect of BMN673 in vitro and in vivo.Conclusion: Our data revealed that AZD5153suppressed the proliferation of colorectal cancer cells and sensitized them to the anticancer effect of the PARP inhibitor BMN673 via Wee1 inhibition in vitro and in vivo. This suggested that targeting BRD4 might be a valuable strategy for colorectal cancer treatment.

Downregulation of lncRNA NEAT1_2 radiosensitizes hepatocellular carcinoma cells through regulation of miR-101-3p/WEE1 axis.

Radioresistance is a major obstacle in hepatocellular carcinoma (HCC) radiotherapy. Aberrant expression of long non-coding RNA (lncRNA) has been postulated to be implicated in the development of HCC radioresistance. We investigated the role of lncRNA nuclear enriched abundant transcript 1_2 (NEAT1_2) in radioresistance of HCC and its molecular mechanism in this study. We found that NEAT1_2 and WEE1 were upregulated, and miR-101-3p was downregulated in HCC tissues, as well as HCC cell lines. Downregulation of WEE1 sensitized the radiosensitivity of HCC cells, as evidenced by decreased survival fractions of Huh7 and PLC5 cells and increased percentage of apoptotic cells. Also, knockdown of NEAT1_2 exerted a reinforcing effect on the radiosensitivity of HCC cells. In addition, WEE1 was confirmed as a direct target of miR-101-3p. Upregulation of miR-101-3p obviously decreased the mRNA and protein levels of WEE1 compared with that in the miR-NC group, while transfection of anta-miR-101-3p presented the opposite effects. In parallel, NEAT1_2 was identified to interact with miR-101-3p, and NEAT1_2 upregulated the expression of WEE1 in Huh7 cells through sponging miR-101-3p. Besides, the reinforcing effect of NEAT1_2 silencing could be attenuated by downregulation of miR-101-3p. To conclude, our results support the concept that downregulation of lncRNA NEAT1_2 radiosensitizes hepatocellular carcinoma cells through regulation of miR-101-3p/WEE1 axis.

The impact of steatosis on liver regeneration.

Alcoholic and non-alcoholic fatty liver diseases are the leading causes of cirrhosis in Western countries. These chronic liver diseases share common pathological features ranging from steatosis to steatohepatitis. Fatty liver is associated with primary liver graft dysfunction, a higher incidence of complications/mortality after surgery, in correlation with impaired liver regeneration. Liver regeneration is a multistep process including a priming phase under the control of cytokines followed by a growth factor receptor activation phase leading to hepatocyte proliferation. This process ends when the initial liver mass is restored. Deficiency in epidermal growth factor receptor (EGFR) liver expression, reduced expression of Wee1 and Myt1 kinases, oxidative stress and alteration in hepatocyte macroautophagy have been identified as mechanisms involved in the defective regeneration of fatty livers. Besides the mechanisms, we will also discuss in this review various treatments that have been investigated in the reversal of the regeneration defect, for example, omega-3 fatty acids, pioglitazone, fibroblast growth factor (FGF)19-based chimeric molecule or growth hormone (GH). Since dysbiosis impedes liver regeneration, targeting microbiota could also be an interesting therapeutic approach.

Porcine reproductive and respiratory syndrome virus inhibits MARC-145 proliferation via inducing apoptosis and G2/M arrest by activation of Chk/Cdc25C and p53/p21 pathway

Porcine reproductive and respiratory syndrome virus(PRRSV) is an important immunosuppressive virus which can suppresses infected cells proliferation. In this work, we examined PRRSV ability to manipulate cell cycle progression of MARC-145 cells and explored the potential molecular mechanisms. The results showed that PRRSV infection imposed a growth-inhibitory effect on MARC-145 cells by inducing cell cycle arrest at G2/M phase. This arrest was due to the significant decrease of Cdc2-cyclinB1 complex activity in PRRSV-infected cells and the activity reduction was a result of Cdc2 Tyr15 phosphorylation and the accumulation of Cdc2 and cyclinB1 in the nucleus. Not only elevated Wee1 and Myt1 expression and inactivated Cdc25C, but also increase of p21 and 14–3-3σ in a p53-dependent manner caused the inhibitory Tyr15 phosphorylation of Cdc2. PRRSV infection also activated Chk1. Our data suggest PRRSV infection induces G2/M arrest via various molecular regulatory mechanisms. These results provide a new insights for PRRSV pathogenesis.

700P - Stemness in hepatocellular carcinoma reduced by inhibition of WEE1 expression

700P - Stemness in hepatocellular carcinoma reduced by inhibition of WEE1 expression

Association between MicroRNA-373 and Long Noncoding RNA NORAD in Hepatitis C Virus-Infected Hepatocytes Impairs Wee1 Expression for Growth Promotion.

Chronic hepatitis C virus (HCV) infection may lead to end-stage liver disease, including hepatocellular carcinoma (HCC). We have shown previously that microRNA-373 (miR-373) is upregulated in HCV-infected human liver biopsy specimens. To gain insight into the role of miR-373 in HCV-mediated pathogenesis, we investigated its interacting partner for hepatocyte growth regulation. Transcriptome sequencing (RNA-seq) data revealed that Wee1 is associated with miR-373 and is a direct target. Interestingly, higher expression of Wee1 was noted in HCV-infected hepatocytes than in uninfected hepatocytes, suggesting that other factors may block miR-373-mediated Wee1 inhibition. We subsequently found an association between the long noncoding RNA NORAD (LINC00657) and miR-373, and we demonstrated that NORAD binds to miR-373 and Wee1 independently. However, the high level of Wee1 expression in HCV-infected hepatocytes suggested that miR-373 forms a complex with NORAD. Depletion of miR-373 or the inhibitor Wee1 reduces the growth of Huh7.5 cells harboring the HCV genome as well as reducing Wee1 expression. Taken together, our data demonstrate a novel mechanism of hepatocyte growth promotion during HCV infection involving a miR-373-NORAD-Wee1 axis, which may be a target for future therapy against HCV-associated HCC.IMPORTANCE The mechanism of HCV-mediated liver pathogenesis is poorly understood. In this study, we observed that HCV infection upregulates miR-373 and Wee1, a pivotal player in the G2 checkpoint in the cell cycle, although Wee1 is a direct target for miR-373. Subsequent investigation demonstrated that miR-373 forms a complex with the long noncoding RNA NORAD, resulting in the release of their common target, Wee1, in HCV-infected cells, which, in turn, favors uncontrolled cell growth. Our study suggested a previously unknown mechanism for hepatocyte growth promotion following HCV infection, and this pathway can be targeted for future therapy against HCV-mediated liver pathogenesis.

Abstract 154: Inhibition of WEE1 expression reduces lipid metabolism and stemness in hepatocellular carcinoma

Abstract Background: Classical therapeutic regimens predominantly target proliferating cells, which are unlikely to be cancer stem cells (CSCs). Similarly, new generation therapies, e.g. sorafenib for hepatocellular carcinoma (HCC), do not seem to target CSCs as evidenced by frequent tumor relapse and resistance after therapy. Thus, identification and characterization of signaling pathways and biomarkers associated with CSC biology are therefore priorities for developing new paradigms of molecular cancer therapeutics. Increase of WEE1 kinase activity through an epigenetic regulation plays an important role in the development of HCC. However, the functional role of WEE1 in HCC progression remains to be clarified. Methods: Human HCC cell lines were transfected with WEE1 siRNA and tested for growth inhibition, apoptotic induction, molecular changes in both RNA and protein levels, and changes in CSC phenotype using various methods such as MTS, FACS, microscopic analysis, Real-time PCR, Western blotting, sphere forming assay. To obtain insights into the molecular changes in response to WEE1 knockdown, global changes in gene expression were examined using RNA sequencing. Results: Here we demonstrated that WEE1 siRNA silencing caused inhibition of HCC cell growth through blockade of cell cycle progression and induction of apoptosis. The anti-proliferative effects were driven by a subset of molecular alterations including the upregulation of cdk inhibitor p21 and the downregulation of AKT1, CDK2, cyclin B1 (CCNB1), PARP1 and GPAM which are functionally involved in control of cell cycle, apoptosis and lipid metabolism. Wee1 silencing in tumor cells also resulted in a strong inhibition of lipogenesis (SREBP1C, FAS) and caused a marked decrease in fat accumulation. Of importance, knockdown of WEE1 dramatically reduced the portion of liver CSC population through co-downregulation of cancer stemness genes and weakened the capacity of sphere formation and the ability of cancer cell migration. Systemic delivery of a modified WEE1 siRNA encapsulated in lipid nanoparticles significantly inhibited human HCC growth in murine xenograft models, and increased mice survival. Our findings suggest that the epigenetic modifier WEE1 functionally involve to HCC lipid metabolism and CSC-like phenotype maintenance and that molecular targeting of WEE1 may be an effective systemic therapy for prevention of tumor recurrence via elimination of CSCs in liver tumor microenvironment. Citation Format: Keon Uk Park, Min Ji Ko, Ilseon Hwang, Hun-Mo Ryoo, Yun-Han Lee. Inhibition of WEE1 expression reduces lipid metabolism and stemness in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 154.

Abstract 509: Upregulation of miR-424 promotes cell cycle progression and cell proliferation in esophageal squamous cell carcinoma

Abstract Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignancies of the gastrointestinal tract. miR-424 was one of the most significantly upregulated miRNAs in the ESCCs compared with normal esophageal tissues (NEs) identified by our previous miRNA arrays. The effects of miR-424 in tumor development and progression are conflicting according to previous reports till now. Here, we characterized the role of miR-424 in ESCC cell cycle progression and proliferation regulation. Expression of miR-424 was determined using qRT-PCR analysis. Cell proliferation assay by CCK-8 and the xenograft tumor model were used to determine ESCC proliferation in vitro and in vivo. Cell cycle distribution was analyzed by flow cytometry after synchronizing and releasing cells from G0/G1 phase, the onset of S-phase, or mitosis. Targets of miR-424 were validated using luciferase assays. The presence of E2F1-binding sites in the putative promoter of miR-424 gene was investigated using Chromatin immunoprecipitation (ChIP). As a result, miR-424 expression was elevated in ESCC specimens than in their normal counterparts. High miR-424 expression was a predictor of poor survival for Stage II-III ESCC patients undergoing surgery. Consistent with clinical data, knockdown miR-424 function in ESCC cells remarkably suppressed ESCC proliferation in vitro and tumor formation in mice model, while opposite results were observed after overexpressing miR-424. Cell cycle analyses revealed that miR-424 knockdown negatively regulates both G1/S and G2/M transition in ESCC cells, which were mediated by two newly identified miR-424 targets PRKCD and WEE1, respectively. During G1/S transition, increased level of PRKCD protein in KYSE410-miRZip-424 cells resulted in increased activation of PRKCD and downstream p38MAPK and JNK, which enhanced the stability of p21Cip1 protein. p21Cip1 proceeded to block CDK2 activation during G1/S transition. On the other hand, level of CDC2 phosphorylation at Tyr15, the inactive state of CDC2, was increased as a result of increased WEE1 expression by miR-424 knockdown when cells were at the G2/M border. Further evaluation of miR-424 expression in various cell cycle phases showed that miR-424 expression increased along with pri-miR-424 and pre-miR-424 when cell cycle progressed from G0/G1- to S-phase in ESCC cells. ChIP results demonstrated that G1/S transcriptional activating regulator E2F1 was enriched in regions of the putative miR-424 promoter containing the predicted E2F1-binding sites. Here, our results proved that miR-424 functions as an onco-miRNA in ESCCs. Activation of E2F1 when ESCC cells at the G1/S border induced the transcription of miR-424, which in turn targeted the expression of key genes to promote cell cycle progression and cell proliferation of ESCCs. Citation Format: Jing Wen, Xiuying Xie, Jianhua Fu. Upregulation of miR-424 promotes cell cycle progression and cell proliferation in esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 509.

Circadian Rhythm of Glucocorticoid Administration Entrains Clock Genes in Immune Cells: A DREAM Trial Ancillary Study.

Adrenal insufficiency (AI) requires lifelong glucocorticoid (GC) replacement. Conventional therapies do not mimic the endogenous cortisol circadian rhythm. Clock genes are essential components of the machinery controlling circadian functions and are influenced by GCs. However, clock gene expression has never been investigated in patients with AI. To evaluate the effect of the timing of GC administration on circadian gene expression in peripheral blood mononuclear cells (PBMCs) of patients from the Dual Release Hydrocortisone vs Conventional Glucocorticoid Replacement in Hypocortisolism (DREAM) trial. Outcome assessor-blinded, randomized, active comparator clinical trial. Eighty-nine patients with AI were randomly assigned to continue their multiple daily GC doses or switch to an equivalent dose of once-daily modified-release hydrocortisone and were compared with 25 healthy controls; 65 patients with AI and 18 controls consented to gene expression analysis. Compared with healthy controls, 19 of the 68 genes were found modulated in patients with AI at baseline, 18 of which were restored to control levels 12 weeks after therapy was switched: ARNTL [BMAL] (P = 0.024), CLOCK (P = 0.016), AANAT (P = 0.021), CREB1 (P = 0.010), CREB3 (P = 0.037), MAT2A (P = 0.013); PRKAR1A, PRKAR2A, and PRKCB (all P < 0.010) and PER3, TIMELESS, CAMK2D, MAPK1, SP1, WEE1, CSNK1A1, ONP3, and PRF1 (all P < 0.001). Changes in WEE1, PRF1, and PER3 expression correlated with glycated hemoglobin, inflammatory monocytes, and CD16+ natural killer cells. Patients with AI on standard therapy exhibit a dysregulation of circadian genes in PBMCs. The once-daily administration reconditions peripheral tissue gene expression to levels close to controls, paralleling the clinical outcomes of the DREAM trial (NCT02277587).

Expression, activation and clinical relevance of CHK1 and CHK2 in metastatic high-grade serous carcinoma

ObjectiveTo analyze the expression and clinical role of CHK1 and CHK2 in metastatic high-grade serous carcinoma (HGSC). MethodsHGSC effusions (n = 335; 280 peritoneal, 55 pleural) were analyzed for protein expression of total CHK1 and its phosphorylated forms p-ser317 and p-ser296, as well as total CHK2 and its phosphorylated form p-thr68 using immunohistochemistry. Expression was analyzed for association with clinicopathologic parameters, including chemotherapy response, and survival. ResultsCarcinoma cells stained positive, predominantly at the nuclei, in the majority of cases (range 83–100% for the five antibodies), while expression in reactive mesothelial cells and tumor-associated macrophages was more variable. Total CHK1 (p = 0.037), p-CHK1ser317 (p = 0.001), p-CHK1ser296 (p = 0.002) and p-CHK2thr68 (p < 0.001) expression was significantly higher in post-chemotherapy disease recurrence compared to pre-chemotherapy effusions obtained at diagnosis. CHK1, p-CHK1ser296, p-CHK2thr68 and p-CHK1ser317 nuclear expression was positively related to expression of the checkpoint regulator WEE1, previously studied in this cohort (p = 0.003, p = 0.013, p = 0.001 and p = 0.01, respectively). Higher total CHK1 (p = 0.007), p-CHK1ser317 (p = 0.004), CHK2 (p = 0.01) and p-CHK2thr68 (p = 0.048) expression was significantly related to shorter overall survival in univariate analysis, and CHK1ser317 was an independent prognostic marker in multivariate analysis (p = 0.025). Higher p-CHK1ser317 (p = 0.03) and CHK2 (p = 0.034) expression was additionally associated with poor progression-free survival. ConclusionsCHK1 and CHK2 and their activated forms are frequently expressed in HGSC effusions, with higher expression following exposure to chemotherapy, and their expression is related to survival.

Whole-Genome Expression Microarray Combined with Machine Learning to Identify Prognostic Biomarkers for High-Grade Glioma.

The aim of our study is to build a framework for a better understanding of high-grade glioma (HGG) prognostic-related biomarkers. Whole-genome gene expression microarray was performed to identify differently expressed genes between HGGs and low-grade diffuse gliomas. Several machine learning algorithms were used to filter prognostic-related genes. One hundred ninety-three HGG patients after surgical resection were selected for survival analysis. Immunohistochemistry were performed on these tumor samples to analyze IDH1 mutation status and protein expression of WEE1. qRT-PCR, western blotting, transwell assays, and scratch wound healing assays were performed to evaluate the effect of WEE1 knockdown or overexpression in HGG cells. Three prognostic-related genes (WEE1, IGF2PB3, and EMP3) were demonstrated to separate HGG patients into two different survival subgroups. The area under receiver operating characteristic curve of WEE1 was higher than that of IGF2BP3, EMP3, age, IDH status, 1p/19q status, and MGMT promoter status. WEE1 was an independent covariate compared with IDH status, age, and WHO grade. Knockdown or overexpression of WEE1 can inhibit or promote migration and invasion in U251 and U87 cell lines. WEE1, EMP3, and IGF2BP3 are reliable prognostic-related genes at the mRNA level. WEE1 is an independent prognostic biomarker in survival analysis and has potential diagnostic value for HGG patients. WEE1 can induce HGG cell migration and invasion in vitro.