28 research outputs found

    Therapeutic Co-targeting of WEE1 and ATM Downregulates PD-L1 Expression in Pancreatic Cancer

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    Purpose Pancreatic cancer (PC) is one of the most lethal cancers worldwide, but there are currently no effective treatments. The DNA damage response (DDR) is under investigation for the development of novel anti-cancer drugs. Since DNA repair pathway alterations have been found frequently in PC, the purpose of this study was to test the DDR-targeting strategy in PC using WEE1 and ATM inhibitors. Materials and Methods We performed in vitro experiments using a total of ten human PC cell lines to evaluate antitumor effect of AZD1775 (WEE1 inhibitor) alone or combination with AZD0156 (ATM inhibitor). We established Capan-1-mouse model for in vivo experiments to confirm our findings. Results In our research, we found that WEE1 inhibitor (AZD1775) as single agent showed anti-tumor effects in PC cells, however, targeting WEE1 upregulated p-ATM level. Here, we observed that co-targeting of WEE1 and ATM acted synergistically to reduce cell proliferation and migration, and to induce DNA damage in vitro. Notably, inhibition of WEE1 or WEE1/ATM downregulated programmed cell death ligand 1 expression by blocking glycogen synthase kinase-3 beta serine 9 phosphorylation and decrease of CMTM6 expression. In Capan-1 mouse xenograft model, AZD1775 plus AZD0156 (ATM inhibitor) treatment reduced tumor growth and downregulated tumor expression of programmed cell death ligand 1, CMTM6, CD163, and CXCR2, all of which contribute to tumor immune evasion. Conclusion Dual blockade of WEE1 and ATM might be a potential therapeutic strategy for PC. Taken together, our results support further clinical development of DDR-targeting strategies for PC.

    Inhibition of ATR Increases the Sensitivity to WEE1 Inhibitor in Biliary Tract Cancer

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    Purpose Currently, the DNA damage response (DDR) pathway represents a key target for new cancer drug development. Advanced biliary tract cancer (BTC) has a poor prognosis because of the lack of efficacious treatment options. Although DNA repair pathway alterations have been reported in many patients with BTC, little is known regarding the effects of DDR-targeted agents against BTC. Materials and Methods In this study, nine BTC cell lines were exposed to the WEE1 inhibitor (AZD1775). In vitro, MTT assay, colony-forming assay, cell cycle analysis, phospho-histone H3 staining assay, Transwell migration assay, and western blot were performed. Then, to enhance the antitumor effect of AZD1775, the combination treatment of WEE1 inhibitor and ataxia telangiectasia mutated and Rad3 related (ATR) inhibitor (AZD6738) was conducted using MTT assay and comet assay. Finally, HuCCT-1 and SNU2670 xenograft models were established to confirm the anti-tumor effect of AZD1775 alone. Furthermore, the combination treatment was also evaluated in SNU2670 xenograft models. Results AZD1775 blocked the phosphorylation of CDC2 and CDC25C in all cell lines, but significantly increased apoptosis and S phase arrest in sensitive cells. However, increased p-ATR and phosphorylated ataxia telangiectasia mutated levels were observed in less sensitive cells. In addition, in vitro and in vivo data illustrated that AZD1775 combined with AZD6738 exerted more potent anti-tumor effects than either drug alone. Although WEE1 inhibition has promising anti-tumor effects in some BTC cells, the addition of ATR inhibitors could enhance its efficacy. Conclusion Taken together, this study supports further clinical development of DDR-targeted strategies as monotherapy or combination regimens for BTC.

    Therapeutic targeting of the DNA damage response using an ATR inhibitor in biliary tract cancer

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    Purpose The DNA damage response (DDR) is a multi-complex network of signaling pathways involved in DNA damage repair, cell cycle checkpoints, and apoptosis. In the case of biliary tract cancer (BTC), the strategy of DDR targeting has not been evaluated, even though many patients have DNA repair pathway alterations. The purpose of this study was to test the DDR-targeting strategy in BTC using an ataxia-telangiectasia and Rad3-related (ATR) inhibitor. Materials and Methods A total of nine human BTC cell lines were used for evaluating anti-tumor effect of AZD6738 (ATR inhibitor) alone or combination with cytotoxic chemotherapeutic agents through MTT assay, colony-forming assays, cell cycle analyses, and comet assays. We established SNU478-mouse model for in vivo experiments to confirm our findings. Results Among nine human BTC cell lines, SNU478 and SNU869 were the most sensitive to AZD6738, and showed low expression of both ataxia-telangiectasia mutated and p53. AZD6738 blocked p-Chk1 and p-glycoprotein and increased gamma H2AX, a marker of DNA damage, in sensitive cells. AZD6738 significantly increased apoptosis, G2/M arrest and p21, and decreased CDC2. Combinations of AZD6738 and cytotoxic chemotherapeutic agents exerted synergistic effects in colony-forming assays, cell cycle analyses, and comet assays. In our mouse models, AZD6738 monotherapy decreased tumor growth and the combination with cisplatin showed more potent effects on growth inhibition, decreased Ki-67, and increased terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling than monotherapy with each drug. Conclusion In BTC, DDR targeting strategy using ATR inhibitor demonstrated promising antitumor activity alone or in combination with cytotoxic chemotherapeutic agents. This supports further clinical development of DDR targeting strategy in BTC

    Resistance Mechanism against Trastuzumab in HER2-Positive Cancer Cells and Its Negation by Src Inhibition

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    Trastuzumab in combination with chemotherapy is the standard of care for patients with human epidermal growth factor receptor 2 (HER2)-positive breast and gastric cancers. Several resistance mechanisms against anti-HER2 therapy have been proposed. Src activation has been suggested to be responsible for the resistance of HER2-positive breast cancer. In our study, we generated four trastuzumab-resistant (HR) cancer cell lines from HER2-amplified gastric and biliary tract cancer cell lines (SNU-216, NCI-N87, SNU-2670, and SNU-2773). Elevated Src phosphorylation was detected in SNU2670HR and NCI-N87HR cell lines, but not in SNU216HR or SNU2773HR cell lines. In SNU216HR and SNU2773HR cell lines, phospho-FAK (focal adhesion kinase) was elevated. Bosutinib as a Src inhibitor suppressed growth, cell-cycle progression, and migration in both parental and HR cell lines. Specifically, Src interacted with FAK to affect downstream molecules such as AKT, ERK, and STAT3. Bosutinib showed more potent antitumor effects in Src-activated HR cell lines than parental cell lines. Taken together, this study suggests that Src inhibition may be an effective measure to overcome trastuzumab resistance in HER2-positive cancer. (C) 2017 AACR

    Prognostic implications of soluble programmed death-ligand 1 and its dynamics during chemotherapy in unresectable pancreatic cancer

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    In pancreatic cancer, acquiring a sufficient amount of tumor tissue is an obstacle. The soluble form of PD-L1 (sPD-L1) may have immunosuppressive activity. Here, we evaluated the prognostic implications of sPD-L1 in unresectable pancreatic cancer. We prospectively enrolled 60 patients treated with first-line FOLFIRINOX chemotherapy. We collected blood samples at diagnosis, first response assessment and disease progression. Serum sPD-L1 levels were measured using enzyme-linked immunosorbent assays. The median sPD-L1 level was 1.7 ng/mL (range, 0.4-5.7 ng/mL). Patients with low sPD-L1 level (<4.6 ng/mL) at diagnosis showed better overall survival (OS) than those with high sPD-L1 level (P= 0.015). Multivariate analysis identified sPD-L1 and the neutrophil-to-lymphocyte ratio as independent prognostic factors for OS. During chemotherapy, more patients achieved complete response (CR)/partia I response (PR) as their best response when sPD-L1 was decreased at the first response assessment (P = 0.038). In the patients who achieved CR/PR as their best response, sPD-L1 was significantly higher at the time of disease progression than at the first response assessment (P = 0.025). In conclusion, the sPD-L1 level at diagnosis exhibits a prognostic value in pancreatic cancer. Furthermore, sPD-L1 dynamics correlate with disease course and could be used to understand various changes in the tumor microenvironment during chemotherapy

    The prognostic role of soluble TGF-beta and its dynamics in unresectable pancreatic cancer treated with chemotherapy

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    Objectives Transforming growth factor-beta (TGF-beta) is a multifunctional regulatory factor. Here we measured serum soluble TGF-beta (sTGF-beta) levels and evaluated its dynamics and prognostic capabilities during chemotherapy in unresectable pancreatic cancer patients. Methods We prospectively enrolled 60 patients treated with FOLFIRINOX as the first-line palliative chemotherapy. We collected blood samples at the time of diagnosis, first response assessment, and disease progression and measured serum sTGF-beta using an enzyme-linked immunosorbent assay. Results The patients' median overall survival (OS) and progression-free survival (PFS) were 10.3 (95% confidence interval [CI], 8.5-12.1) and 6.5 (95% CI, 4.9-8.1) months, respectively. Patients with low sTGF-beta at diagnosis (<31.2 ng/mL) had better OS and PFS than patients with high sTGF-beta, respectively, (OS, 13.7 vs 9.2 months; hazard ratio [HR], 2.602; P = .004; PFS, 9.0 vs 5.8 months; HR, 2.010; P = .034). At the time of disease progression, sTGF-beta was increased compared with that of diagnosis (mean, 26.4 vs 23.9 ng/mL). In particular, sTGF-beta was significantly increased at disease progression in patients with a partial response (mean, 25.7 vs 31.0 ng/mL; P = .049). Conclusions Pretreatment sTGF-beta levels can serve as a prognostic indicator in unresectable pancreatic cancer patients treated with FOLFIRINOX chemotherapy. Likewise, the dynamics of sTGF-beta during chemotherapy have prognostic value.

    Anti-tumor effects of NVP-BKM120 alone or in combination with MEK162 in biliary tract cancer

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    There are currently no clinically validated therapeutic targets for biliary tract cancer (BTC). Despite promising results in other cancers, compounds targeting the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, alone or in combination with Ras/Raf/MEK pathway inhibitors, have not been evaluated in BTC. Here, we examined the effects of a pan-PI3K inhibitor (BKM120) with or without a MEK inhibitor (MEK162), on eight human BTC cell lines carrying mutations in K-Ras and/or the PI3K catalytic subunit, P13KCA. BKM120 inhibited the colony-forming ability and migration of BTC cells carrying wild-type (WT) PI3KCA and either mutant (MT) or WT K-Ras, but not of cells carrying mutations in both genes. In K-Ras-WT cells, BKM120 decreased the phosphorylation of Akt, its downstream effector kinase p70S6K, and the translational repressor 4E-BP1. Interestingly, BKM120 did not induce cell cycle arrest or suppress PI3K signaling via restoration of p-4E-BP1 in cells with PIK3CA and K-Ras double mutations. Notably, the resistance of dual K-Ras/PI3KCA-mutant cells to BKM120 was overcome by treatment with a combination of BKM120 and MEK162. Our findings thus support the clinical development of BKM120 monotherapy or BKM120/MEK162 combination therapy for the treatment of BTC. (c) 2017 Elsevier B.V. All rights reserved

    Dynamics of soluble programmed death-ligand 1 (SPDL1) during chemotherapy and its prognostic implications in cancer patients: Biomarker development in immuno-oncology

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    Purpose The soluble programmed death-ligand 1 (sPDL1) has immunosuppressive activity and is a candidate biomarker for immuno-oncology drug development. In this study, we measured sPDL1 at pre-and post-chemotherapy and at disease progression to uncover the dynamics of sPDL1 during treatment in biliary tract cancer (BTC) patients. Materials and Methods From 90 BTC patients (training cohort, 53; validation cohort, 37) who were candidates for palliative first-line chemotherapy, blood was collected at pre-and post-chemotherapy (at the time of best response) and at disease progression. The sPDL1 levels were measured using an enzyme-linked immunosorbent assay. Responses to chemotherapy, overall survival (OS), and other prognostic factors including the neutrophil-lymphocyte ratio (NLR) were analyzed. Results The OS of all patients was 11.5 months (confidence interval [CI], 9.7 to 16.2). The best response was complete response in seven (7.8%), partial response in 20 (22.2%), stable disease in 52 (57.8%), and disease progression (PD) in 11 patients (12.2%). Patients with high pre-chemotherapy sPDL1 (>= 1.30 ng/mL) showed worse OS than patients with low prechemotherapy sPDL1 (9.1 months vs. 12.5 months, p=0.003). In multivariate analyses, high pre-chemotherapy sPDL1 (hazard ratio [HR], 1.96; 95% CI, 1.2 to 3.9; p=0.011) and high pre-chemotherapy NLR (HR, 1.82; 95% CI, 1.1 to 3.0; p=0.020) were independent poor prognostic factors for OS. At the time of PD, sPDL1 was increased significantly compared with pre-chemotherapy sPDL1 (1.59 ng/mL vs. 0.72 ng/mL, p=0.003). Conclusion The sPDL1 at pre-chemotherapy confers the prognostic value for OS in BTC patients under palliative chemotherapy. The dynamics of sPDL1 during chemotherapy correlate with disease burden and have prognostic value

    Jab1 silencing inhibits proliferation and sensitizes to cisplatin in biliary tract cancer

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    Purpose Jab1 is a coactivator of c-Jun that enhances the transcriptional function of c-Jun. Jab1 is frequently overexpressed in various cancers and is associated with poor prognosis of cancer patients. Thus, Jab1 could be a potential therapeutic target in cancer. However, the role of Jab1 in biliary tract cancer (BTC) has not been studied. Materials and Methods We performed in vitro and in vivo experiments to evaluate the therapeutic potential of Jab1 inhibition in BTC. Results Among 8 BTC cell lines, many showed higher Jab1 expression levels. In addition, Jab1 silencing by siRNA increased p27 expression levels. SNU478 and HuCCT-1 cells exhibited profound Jab1 knockdown and increased p27 expression by Jab1-specific siRNA transfection. Jab1 silencing induced anti-proliferative and anti-migratory effects and resulted in G1 cell cycle arrest in SNU478 and HuCCT-1 cells. In addition, Jab1 silencing potentiated the anti-proliferative and anti-migratory effects of cisplatin by increasing DNA damage. Interestingly, Jab1 knockdown increased PTEN protein half-life, resulting in increased PTEN expression. In the HuCCT-1 mouse xenograft model, stable knockdown of Jab1 by shRNA also showed anti-proliferative effects in vivo, with decreased Ki-67 expression and AKT phosphorylation and increased Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and p27 expression. Conclusion Jab1 knockdown demonstrated anti-proliferative and anti-migratory effects in BTC cells by increasing DNA damage and stabilizing PTEN, resulting in G1 cell cycle arrest. In addition, Jab1 silencing potentiated the anti-proliferative effects of cisplatin. Our data suggest that Jab1 may be a potential therapeutic target in BTC that is worthy of further investigations
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