RNAi screening of the kinome with cytarabine in leukemias

Tibes, Raoul; Bogenberger, James M; Chaudhuri, Leena; Hagelstrom, R. Tanner; Chow, Donald; Buechel, Megan; Gonzales, Irma M.; Demuth, Tim; Slack, James L.; Mesa, Ruben A.; Braggio, Esteban; Yin, Hongwei; Arora, Shilpi; Azorsa, David O.

doi:10.1182/blood-2011-07-367557

Cited by 75 publications

(77 citation statements)

References 35 publications

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“…Our observations that low PKMYT1 mRNA expression is common among the most sensitive cell lines to MK-1775 and that knockdown of PKMYT1 can sensitize less responsive cell lines to MK-1775 together suggest functional redundancy between PKMYT1 and WEE1. In support of this, siRNA studies have shown that knockdown of PKMYT1 leads to similar, although less pronounced, abrogation of G 2 cell-cycle arrest and sensitization to DNA-damaging agents (31,36,37). Furthermore, and similar to WEE1, overexpression of PKMYT1 is sufficient to induce a G 2 cell-cycle delay in HeLa cells (38).…”

Section: Discussionmentioning

confidence: 56%

Preclinical Evaluation of the WEE1 Inhibitor MK-1775 as Single-Agent Anticancer Therapy

Guertin

Liu

et al. 2013

Molecular Cancer Therapeutics

153

142

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Inhibition of the DNA damage checkpoint kinase WEE1 potentiates genotoxic chemotherapies by abrogating cell-cycle arrest and proper DNA repair. However, WEE1 is also essential for unperturbed cell division in the absence of extrinsic insult. Here, we investigate the anticancer potential of a WEE1 inhibitor, independent of chemotherapy, and explore a possible cellular context underlying sensitivity to WEE1 inhibition. We show that MK-1775, a potent and selective ATP-competitive inhibitor of WEE1, is cytotoxic across a broad panel of tumor cell lines and induces DNA double-strand breaks. MK-1775-induced DNA damage occurs without added chemotherapy or radiation in S-phase cells and relies on active DNA replication. At tolerated doses, MK-1775 treatment leads to xenograft tumor growth inhibition or regression. To begin addressing potential response markers for MK-1775 monotherapy, we focused on PKMYT1, a kinase functionally related to WEE1. Knockdown of PKMYT1 lowers the EC 50 of MK-1775 by five-fold but has no effect on the cell-based response to other cytotoxic drugs. In addition, knockdown of PKMYT1 increases markers of DNA damage, gH2AX and pCHK1 S345 , induced by MK-1775. In a post hoc analysis of 305 cell lines treated with MK-1775, we found that expression of PKMYT1 was below average in 73% of the 33 most sensitive cell lines. Our findings provide rationale for WEE1 inhibition as a potent anticancer therapy independent of a genotoxic partner and suggest that low PKMYT1 expression could serve as an enrichment biomarker for MK-1775 sensitivity.

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Section: Discussionmentioning

confidence: 56%

Preclinical Evaluation of the WEE1 Inhibitor MK-1775 as Single-Agent Anticancer Therapy

Guertin

Liu

et al. 2013

Molecular Cancer Therapeutics

153

142

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“…40, 51,52 Tibes et al used an RNAi screening approach to identify kinases involved in cytarabine sensitivity and found ATR, PKMYT1, and CHK1, among others, as kinases involved in cytarabine sensitivity. 36 In addition, they demonstrated synergistic anti-leukemic activity for combined MK-1775 and cytarabine treatment in cell line models. In contrast to MK-1775 combined with cytarabine, Van Linden et al found that doxorubicin in combination with MK-1775 was largely antagonistic.…”

Section: Discussionmentioning

confidence: 99%

“…36,40,51,52 The combined cytarabine and MK-1775 treatments resulted in synergistic inhibition of proliferation, regardless of p53 status. 40 It has been demonstrated that cytarabine-induced S-phase cell cycle arrest was overcome by the addition of MK-1775.…”

Section: Discussionmentioning

confidence: 99%

Synergistic anti-leukemic interactions between panobinostat and MK-1775 in acute myeloid leukemia ex vivo

Zhang

Edwards

et al. 2015

Cancer Biology & Therapy

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MK-1775 is the first-in-class selective Wee1 inhibitor which has been demonstrated to synergize with CHK1 inhibitors in various malignancies. In this study, we report that the pan-histone deacetylase inhibitor (HDACI) panobinostat synergizes with MK-1775 in acute myeloid leukemia (AML), a malignancy which remains a clinical challenge and requires more effective therapies. Using both AML cell line models and primary patient samples, we demonstrated that panobinostat and MK-1775 synergistically induced proliferation arrest and cell death. We also demonstrated that panobinostat had equal anti-leukemic activities against primary AML blasts derived from patients either at initial diagnosis or at relapse. Interestingly, treatment with panobinostat alone or in combination with MK-1775 resulted in decreased Wee1 protein levels as well as downregulation of the CHK1 pathway. shRNA knockdown of CHK1 significantly sensitized AML cells to MK-1775 treatment, while knockdown of Wee1 significantly enhanced both MK-1775-and panobinostat-induced cell death. Our results demonstrate that panobinostat synergizes with MK-1775 in AML cells, at least in part through downregulation of CHK1 and/or Wee1, providing compelling evidence for the clinical development of the combination treatment in AML.

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“…It was also reported that inhibition of WEE1 could improve the effects of radiotherapy and chemotherapy to induce DNA damage in different cancer cells (Bridges et al, 2011;Carrassa et al, 2012). Suppression of WEE1 in leukemia cell lines or ex-vivo derived leukemia cells also made the cells more sensitive to conventional drugs (Tibes et al, 2012). Recently it was shown that pushing breast cancer cells through G2 arrest, which results from inhibition or loss of WEE1, may allow DNA damage to accumulate and induce programmed cell death in breast cancer cells (Murrow et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Tumour Suppressive Effects of WEE1 Gene Silencing in Breast Cancer Cells

Ghiasi¹,

Habibagahi²,

Rosli³

et al. 2013

Asian Pacific Journal of Cancer Prevention

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Background: WEE1 is a G2/M checkpoint regulator protein. Various studies have indicated that WEE1 could be a good target for cancer therapy. The main aim of this study was to asssess the tumor suppressive potential of WEE1 silencing in two different breast cancer cell lines, MCF7 which carries the wild-type p53 and MDA-MB468 which contains a mutant type. Materials and Methods: After WEE1 knockdown with specific shRNAs downstream effects on cell viability and cell cycle progression were determined using MTT and flow cytometry analyses, respectively. Real-time PCR and Western blotting were conducted to assess the effect of WEE1 inhibition on the expression of apoptotic (p53) and anti-apoptotic (Bcl2) factors and also a growth marker (VEGF). Results: The results showed that WEE1 inhibition could cause a significant decrease in the viability of both MCF7 and MDA-MB-468 breast cancer cell lines by more than 50%. Interestingly, DNA content assays showed a significant increase in apoptotic cells following WEE1 silencing. WEE1 inhibition also induced upregulation of the apoptotic marker, p53, in breast cancer cells. A significant decrease in the expression of VEGF and Bcl-2 was observed following WEE1 inhibition in both cell lines. Conclusions: In concordance with previous studies, our data showed that WEE1 inhibition could induce G2 arrest abrogation and consequent cell death in breast cancer cells. Moreover, in this study, the observed interactions between the pro-and anti-apoptotic proteins and decrease in the angiogenesis marker expression confirm the susceptibility to apoptosis and validate the tumor suppressive effect of WEE1 inhibition in breast cancer cells. Interestingly, the levels of the sensitivity to WEE1 silencing in breast cancer cells, MCF7 and MDA-MB468, seem to be in concordance with the level of p53 expression.

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RNAi screening of the kinome with cytarabine in leukemias

Cited by 75 publications

References 35 publications

Preclinical Evaluation of the WEE1 Inhibitor MK-1775 as Single-Agent Anticancer Therapy

Preclinical Evaluation of the WEE1 Inhibitor MK-1775 as Single-Agent Anticancer Therapy

Synergistic anti-leukemic interactions between panobinostat and MK-1775 in acute myeloid leukemia ex vivo

Tumour Suppressive Effects of WEE1 Gene Silencing in Breast Cancer Cells

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