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  • Anan-Nemoto, Tomoe  (4)
  • Tokuhira, Michihide  (4)
  • 1
    In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 5613-5613
    Abstract: Multiple myeloma (MM) is a hematological malignancy characterized by abnormal clonal proliferation of malignant plasma cells. Despite the introduction of novel agents such as proteasome inhibitors, immunomodulatory drugs, and antibodies that have significantly improved clinical outcomes of the patients of MM, most patients eventually relapse and develop drug resistance. In particular, the prognosis of patients harboring either chromosome TP53 deletion or mutations remains very poor, suggesting the prevalence of TP53 abnormalities increases with disease progression. Therefore, novel therapeutic strategies to overcome this unfavorable feature are urgently needed in clinical settings. WEE1 is a cell-cycle checkpoint kinase and a key regulator of DNA damage surveillance pathways. In response to extrinsically induced DNA damage, WEE1 kinase induces cell cycle arrest, allowing damaged DNA to be repaired before the cell undergoes DNA replication in S phase, and preventing cells harboring unrepaired, damaged DNA from mitotic lethality. Furthermore, WEE1 overexpression has been observed in many types of cancers. In addition, our previous studies revealed that monotherapy with AZD1775, a potent and highly selective inhibitor of WEE1, inhibited the proliferation of various MM cell lines irrespective of TP53 status. (Blood 2016; 128: 3256). On the other hand, one of the defining features of MM cells is the production of large amounts of protein, such as immunoglobulin, that must be processed within the endoplasmic reticulum (ER). Due to the accumulation of abundant immunoglobulin in ER, MM cells are constitutively under conditions of ER stress. The unfolded protein response (UPR)-signaling pathway is a cytoprotective mechanism against ER stress, and is therefore activated in MM cells to survive these conditions. Activation of the UPR has been observed in many types of cancers, and loss of TP53 has shown to enhance the UPR. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is one of three ER transmembrane protein kinases implicated as primary effectors of the UPR. Recent studies have suggested that PERK inhibition resulted in dose-dependent inhibition of tumor growth both in vitro and in vivo. In addition, more recent studies have proposed that PERK induces resistance to cell death elicited by chemotherapy. The combination of WEE1 and PERK inhibitors might thus offer an attractive therapeutic option against this incurable hematological malignancy. Here, we investigated the therapeutic utility of AZD1775 and GSK2606414, a highly selective inhibitor of PERK kinase, alone and in combination in various MM cells including TP53 wild-type (MM1.S) as well as TP53-deficient (KMS-11) and TP53-mutated (U266, RPMI8226, OPM-2) cell lines. AZD1775 and GSK2606414 alone induced dose-dependent cell growth inhibition in all investigated MM cells irrespective of TP53 status. Interestingly, GSK2606414 in combination with AZD1775 inhibited proliferation of all MM cells more effectively than either single agent. Assays for apoptotic cell death demonstrated that AZD1775 in combination with GSK2606414 induced significant and marked apoptotic cell death in MM cells used in this study compared to monotherapy alone. Next, western blotting analysis was performed to address the mechanisms of apoptotic cell death by the treatment of WEE1 and PERK inhibitors in MM cells. GSK2606414 inhibited PERK activation and decreased its downstream substrates (phospho-eIF2a, ATF4, and CHOP). Combination treatment with WEE1 inhibitor and various doses of PERK inhibitor significantly increased PARP and caspase 3 cleavage, CDK1 phosphorylation, and histone H2AX expression. Taken together, these data suggest that combining AZD1775 and GSK2606414 synergistically induced DNA damage and promoted premature mitotic entry, resulting in apoptotic cell death of TP53-deleted or -mutated MM cells. In conclusion, dual targeting of WEE1 and PERK might be a promising therapeutic approach for MM irrespective of TP53 status. Disclosures Tokuhira: Bristol-Myers Squibb: Speakers Bureau; AYUMI Pharmaceutical Corporation: Speakers Bureau; Mitsubishi Tanabe Pharma Corporation: Speakers Bureau; Chugai: Speakers Bureau. Kizaki:Novartis: Speakers Bureau; Bristol-Myers Squibb: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Nippon Shinyaku,: Research Funding, Speakers Bureau.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2018
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 2
    In: Blood, American Society of Hematology, Vol. 128, No. 22 ( 2016-12-02), p. 3256-3256
    Abstract: Multiple myeloma (MM) is a hematological malignancy that derives from the proliferation of unregulated plasma cells. Dramatic improvement in the clinical outcomes of both newly diagnosed and relapsed/refractory patients with MM has been achieved using many clinical approaches, including use of high-dose chemotherapy followed by hematopoietic stem cell transplantation, and new drugs, such as proteasome inhibitors, immunomodulatory drugs, and histone deacetylase inhibitors. However, most patients eventually relapse and develop drug resistance. Moreover, the prognosis of patients with bortezomib (BTZ) and/or lenalidomide (LEN)-resistant MM (key drugs in the treatment of MM) is very poor. Therefore, novel therapeutic approaches to overcome BTZ and LEN resistance are urgently needed in clinical settings. WEE1 is a cell-cycle checkpoint kinase and a key regulator of DNA damage surveillance pathways. In response to extrinsically induced DNA damage, WEE1 catalyzes inhibitory phosphorylation of both cyclin-dependent kinase1 and 2 (CDK1 and CDK2), leading to CDK1- and CDK2-induced cell cycle arrest at the G1, S, or G2-M phases. This cell-cycle arrest, in turn, allows for the damaged DNA to be repaired before the cell undergoes DNA replication, and prevents cells harboring unrepaired damaged DNA from mitotic lethality. Furthermore, recent research has shown that knockdown of WEE1 leads to DNA double-strand breaks specifically in S-phase cells undergoing DNA replication, and that WEE1 is most active in the S-phase, suggesting that WEE1 is involved in DNA synthesis. Overexpression of WEE1 has been observed in many types of cancers, including hepatic cancer, breast cancer, glioblastoma and gastric cancer, and high expression of WEE1 has been shown to correlate with poor prognosis. In addition, research has shown that inhibition of checkpoint kinase 1 (Chk1), a critical transducer of the DNA damage response, potentiates the cytotoxicity of chemotherapy on p53-deficient MM cells, which are regarded as chemotherapy-resistant, suggesting that inhibition of cell-cycle checkpoint kinase is involved in re-sensitization of refractory MM cells to anticancer drugs. These data suggest that WEE1 might be an attractive target for novel therapeutic agents against this incurable hematological malignancy. MK-1775 is a potent and highly-selective small-molecule inhibitor of WEE1. In the present study, we investigated the role of WEE1 in MM as a potential therapeutic target using MK-1775. MTSassays showed that single agent MK-1775 inhibited the proliferation of various MM cell lines, including the intrinsically LEN-resistant cell line, RPMI-8226, in a dose- (0 to 10 mM) and time- (0 to 72 h) dependent manner. Furthermore, the growth inhibition effect is irrespective of p53 status. To examine the mechanisms behind the growth inhibition effect induced by MK-1775, assays for apoptotic cell death were performed. These assays demonstrated that MK-1775 induces both early and late apoptosis in MM cells. To investigate the molecular mechanisms of MK-1775-induced cell death in MM cells, the expression of various cell death-associated proteins and downstream molecules of WEE1 were examined. Western blotting analysis showed that MK-1775 arrested cell growth and induced apoptotic cell death in MM cells in a dose-dependent manner by inhibiting both, the expression of the target molecules of Bcl-2 and MCL1, and the cleavage of PARP and Caspase 3. Similarly, there was a substantial inhibition of CDK1 phosphorylation downstream of WEE1. Moreover, an increased expression of histone H2AX was observed following administration of MK-1775, suggesting that MK-1775 results in cytotoxicity by direct DNA damage. Next, we examined the effects of MK-1775 on BTZ-resistant MM cells. Interestingly, MK-1775 inhibited the proliferation of both BTZ-sensitive wild-type MM cells and BTZ-resistant MM cells, suggesting that BTZ resistance can be overcome by targeting WEE1. Furthermore, in combination with BTZ, MK-1775 was able to re-sensitize BTZ-resistant MM cells to BTZ. These results indicate that inhibition of WEE1 might serve as an attractive therapeutic option for patients with both BTZ-resistant and LEN-resistant MM. In conclusion, our data suggest that WEE1 might be a promising molecular target for the treatment of MM. Disclosures Tokuhira: Bristol Myers Squibb Co., Ltd: Honoraria; Pfizer Co., Ltd: Honoraria; Eizai Co., Ltd: Honoraria.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2016
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 3
    In: International Journal of Hematology, Springer Science and Business Media LLC, Vol. 105, No. 1 ( 2017-1), p. 100-103
    Type of Medium: Online Resource
    ISSN: 0925-5710 , 1865-3774
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2017
    detail.hit.zdb_id: 2028991-1
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  • 4
    In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 1589-1589
    Abstract: [Background] Methotrexate - induced lymphoproliferative disorders (MTX-LPDs) belong to the group of other iatrogenic immunodeficiency-associated LPDs, as defined in the revised 4th edition of the World Health Organization (WHO) classification. The phenomenon of LPD regression after MTX withdrawal is a specific event that develops in patients with autoimmune diseases (ADs), such as rheumatoid arthritis (RA). Although patients with regressive MTX-LPDs have better overall survival (OS), relapse/regrowth (R/R) events after regression are one of the factors of poor prognosis. Recent studies including ours have shown that lymphocytes play an important role in the regressive LPD phenomenon in MTX-LPDs (Rheumatology (Oxford). 2017;56:940-946, Front Immunol. 2018;4;9:621) ; however, little is known of the details regarding differences among the LPD subtypes and the influence of lymphocytes on R/R events. In this study, we analyzed patients with regressive Hodgkin lymphoma (HL) and diffuse large B cell lymphoma (DLBCL), especially focusing on the influence of the absolute lymphocyte count (ALC) on R/R events and clinical outcomes. [Methods] Data were collected from 25 patients with ADs who developed LPD and had regressive LPD after MTX withdrawal at our institutions. All diagnoses were confirmed based on immunohistochemistry analysis of paraffin-embedded samples. All pathological samples were classified and diagnosed according to the WHO classification. The ALCs were determined at the time of MTX withdrawal due to LPD development (0 M), 1 month after MTX withdrawal (1 M), 6 months after MTX withdrawal (6 M), and at the time of R/R. The OS was calculated between 0 M and the time of the last observation. Statistical analyses were performed using EZR software. [Results] Of 25 patients with regressive MTX-LPDs, the median age at 0 M was 67 years (range: 44ー84). Ten men and 15 women were included. The basal ADs were RA (N = 23), psoriasis vulgaris (N = 1), and systemic lupus erythematosus (N = 1). The median duration of MTX treatment was 5.5 years. Seventeen cases of DLBCL and 8 cases of HL were included. The median ALCs at 0 M and 1 M in all patients were 627/µL and 1364/µL, respectively. The median ALC ratio (ALC at 1 M divided by ALC at 0 M) was 2.3 (0.6-8), and it indicated over 1 in 24 patients, confirming ALC recovery at 1 M. Regarding the ALCs at 0 M and 1 M, significant differences between DLBCL and HL were not detected (p=0.215 and p=0.77, respectively).  Of all patients, the median duration from the time of MTX duration to R/R was 12 months (range, 7-41). Thirteen patients remained in the remission state without R/R (Regression group), whereas 12 patients experienced an R/R event (R/R group). In the latter group, the median ALCs at 0 M, 1 M, 6 M, and R/R were 582/µL, 1194/µL, 1158/µL, and 565/µL, respectively. The ALC significantly increased at 1 M from 0 M (p=0.006) and decreased at R/R from 1 M (p=0.05), suggesting that the ALC recovery diminished when the LPD underwent R/R. On the other hand, among 13 patients in the regressive group, the median ALCs at 1 M, 6 M, and at the time of the last observation were over 1500/µL (1732/µL, 1782/µL, and 1574/µL, respectively), although that at 0 M was less than 1000/µL (991/µL). To investigate the influence of ALC on the OS, we analyzed the clinical definition of the ALC cut-off of 1000/µL after the ALC recovery observed at 1 M. The result indicated that patients with ALC greater than or equal to 1000/µL after 6 M had significantly better OS compared to those with ALC less than 1000/µL after 6 M (5-year OS, 100% vs. 43.8%, p=0.00048), considering that the ALC is one of the strong prognostic factors in the clinical outcomes of MTX-LPDs. It is of note that the R/R rate in patients with HL was higher than that in those with DLBCL (100% and 23.4%, respectively), and all 8 patients with HL had an ALC at R/R of less than 1000/µL. [Summary] In this study, we demonstrated that ALC recovery was detected at 1 M, which continued during the clinical course in patients who maintained a remission state, although it decreased to less than 1000/µL after ALC recovery in patients with R/R LPDs. In addition, the ALC of 1000/µL was a critical level affecting the clinical outcomes. Regarding LPD subtypes, the reason for higher R/R rates observed in HL compared to those in DLBCL was thought to be dependent on the rates of lower ALCs. [Conclusion] Our data suggest that the ALC is one of the predictive factors for R/R and OS in patients with regressive MTX-LPDs. Disclosures Tokuhira: Mitsubishi Tanabe Pharma Corporation: Speakers Bureau; AYUMI Pharmaceutical Corporation: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Chugai: Speakers Bureau. Tamaru:Nichirei Bioscience INC.: Research Funding; Takeda Pharmaceutical Company Limited: Speakers Bureau. Kizaki:Nippon Shinyaku,: Research Funding, Speakers Bureau; Celgene: Research Funding, Speakers Bureau; Bristol-Myers Squibb: Research Funding, Speakers Bureau; Novartis: Speakers Bureau.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    RVK:
    RVK:
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2018
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
    Location Call Number Limitation Availability
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