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Anti-Tumor Effect of Heat-Killed Bifidobacterium bifidum on Human Gastric Cancer through Akt-p53-Dependent Mitochondrial Apoptosis in Xenograft Models. Int J Mol Sci 2022; 23:ijms23179788. [PMID: 36077182 PMCID: PMC9456556 DOI: 10.3390/ijms23179788] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/04/2022] Open
Abstract
Paraprobiotics, inactivated microbial cells, regulate immune system and exhibit antioxidant and anti-inflammatory activities in patients with weakened immunity or the elderly. This study evaluated the anti-tumor effects of heat-killed Bifidobacterium and Lactobacillus on human gastric cancer MKN1 cells in vitro and in vivo in xenograft animal models. First, cytotoxicity and apoptosis in MKN1 cells of 11 different heat-killed Bifidobacterium or Lactobacillus strains were examined using the MTT assay or flow cytometry, respectively. Then, BALB/c nude mice xenograft animal models were implanted with human gastric cancer MKN1 cells and orally administered a selected single or a mixture of heat-killed bacterial strains to investigate their inhibitory effect on tumor growth. In addition, the expression of p-Akt, p53, Bax, Bak, cleaved caspase-9, -3, and PARP in the tumor tissues was analyzed using Western blotting assay or immunohistochemistry staining. The results show that heat-killed B. bifidum MG731 (MG731), L. reuteri MG5346 (MG5346), and L. rhamnosus MG5200 (MG5200) induced relatively greater apoptosis than other strains in MKN1 cells. Oral administration of a single dose or a mixture of MG731, MG5346, or MG5200 significantly delayed tumor growth, and MG731 had the most effective anti-tumor effect in the xenograft model. Protein expression of p-Akt, p53, Bax, cleaved caspase-3 and -9, and PARP in tumors derived from the xenograft model correlated with the results of the immunohistochemistry staining.
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2
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Martin JC, Sims JR, Gupta A, Bakin AV, Ohm JE. WEE1 inhibition augments CDC7 (DDK) inhibitor-induced cell death in Ewing sarcoma by forcing premature mitotic entry and mitotic catastrophe. CANCER RESEARCH COMMUNICATIONS 2022; 2:471-482. [PMID: 36338546 PMCID: PMC9635308 DOI: 10.1158/2767-9764.crc-22-0130] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/08/2022] [Accepted: 05/25/2022] [Indexed: 06/16/2023]
Abstract
Ewing sarcoma is an aggressive childhood cancer for which treatment options remain limited and toxic. There is an urgent need for the identification of novel therapeutic strategies. Our group has recently shown that Ewing cells rely on the S-phase kinase CDC7 (DDK) to maintain replication rates and cell viability and that DDK inhibition causes an increase in the phosphorylation of CDK1 and a significant delay in mitotic entry. Here, we expand on our previous findings and show that DDK inhibitor-induced mitotic entry delay is dependent upon WEE1 kinase. Specifically, WEE1 phosphorylates CDK1 and prevents mitotic entry upon DDK inhibition due to the presence of under-replicated DNA, potentially limiting the cytotoxic effects of DDK inhibition. To overcome this, we combined the inhibition of DDK with the inhibition of WEE1 and found that this results in elevated levels of premature mitotic entry, mitotic catastrophe, and apoptosis. Importantly, we have found that DDK and WEE1 inhibitors display a synergistic relationship with regards to reducing cell viability of Ewing sarcoma cells. Interestingly, the cytotoxic nature of this combination can be suppressed by the inhibition of CDK1 or microtubule polymerization, indicating that mitotic progression is required to elicit the cytotoxic effects. This is the first study to display the potential of utilizing the combined inhibition of DDK and WEE1 for the treatment of cancer. We believe this will offer a potential therapeutic strategy for the treatment of Ewing sarcoma as well as other tumor types that display sensitivity to DDK inhibitors.
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Affiliation(s)
- Jeffrey C. Martin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Jennie R. Sims
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Ajay Gupta
- Division of Pediatric Oncology, Roswell Park Comprehensive Cancer Center, Department of Pediatrics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Andrei V. Bakin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Joyce Ellen Ohm
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
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3
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Martin JC, Sims JR, Gupta A, Hagoel TJ, Gao L, Lynch ML, Woloszynska A, Melendy T, Kane JF, Kuechle J, Ohm JE. CDC7 kinase (DDK) inhibition disrupts DNA replication leading to mitotic catastrophe in Ewing sarcoma. Cell Death Discov 2022; 8:85. [PMID: 35220396 PMCID: PMC8882187 DOI: 10.1038/s41420-022-00877-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 01/26/2022] [Accepted: 02/08/2022] [Indexed: 12/27/2022] Open
Abstract
Ewing sarcoma is the second most common bone malignancy in children and adolescents. In recent years, a large body of evidence has emerged that suggests Ewing tumors harbor large amounts of replication stress (RS). CDC7, also known as DDK (DBF4-dependent kinase), is a serine/threonine kinase that is involved in a diverse array of cellular functions including the regulation of DNA replication initiation and activation of the RS response. Due to DDK's diverse roles during replication, coupled with the fact that there is an increased level of RS within Ewing tumors, we hypothesized that Ewing sarcoma cells would be particularly vulnerable to DDK inhibition. Here, we report that DDK inhibition resulted a significant reduction in cell viability and the induction of apoptosis, specifically in Ewing sarcoma cells. Treatment with DDK inhibitors dramatically reduced the rate of replication, prolonged S-phase, and led to a pronounced increase in phospho-CDC2 (Y15), indicating delay of mitotic entry. The induction of cell death corresponded to mitotic exit and G1 entry, suggesting improper mitotic progression. In accordance with this, we find that DDK inhibition caused premature mitotic entry resulting in mitotic abnormalities such as anaphase bridges, lagging chromosomes, and cells with >2 poles in Ewing sarcoma cells. This abnormal progression through mitosis resulted in mitotic catastrophe as evidenced by the formation of micronuclei and induction of DNA damage. Together, these findings suggest that DDK activity is required for the faithful and timely completion of DNA replication in Ewing cells and that DDK inhibition may present a viable therapeutic strategy for the treatment of Ewing sarcoma.
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Affiliation(s)
- Jeffrey C. Martin
- grid.240614.50000 0001 2181 8635Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Jennie R. Sims
- grid.240614.50000 0001 2181 8635Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Ajay Gupta
- grid.273335.30000 0004 1936 9887Division of Pediatric Oncology, Roswell Park Comprehensive Cancer Center, Department of Pediatrics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY USA
| | - Tamara J. Hagoel
- grid.273335.30000 0004 1936 9887Division of Pediatric Oncology, Roswell Park Comprehensive Cancer Center, Department of Pediatrics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY USA
| | - Lingqiu Gao
- grid.240614.50000 0001 2181 8635Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Miranda L. Lynch
- grid.249447.80000 0004 0422 1994Hauptman-Woodward Medical Research Institute, Buffalo, NY USA
| | - Anna Woloszynska
- grid.240614.50000 0001 2181 8635Department of Pharmacology & Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Thomas Melendy
- grid.273335.30000 0004 1936 9887Department of Microbiology and Immunology, State University of New York at Buffalo, Buffalo, NY USA
| | - Jeremy F. Kane
- grid.240614.50000 0001 2181 8635Department of Surgery, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Joseph Kuechle
- grid.240614.50000 0001 2181 8635Department of Surgery, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
| | - Joyce E. Ohm
- grid.240614.50000 0001 2181 8635Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, NY USA
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4
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Structural Basis for the Activation and Target Site Specificity of CDC7 Kinase. Structure 2020; 28:954-962.e4. [PMID: 32521228 PMCID: PMC7416108 DOI: 10.1016/j.str.2020.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/11/2020] [Accepted: 05/19/2020] [Indexed: 12/13/2022]
Abstract
CDC7 is an essential Ser/Thr kinase that acts upon the replicative helicase throughout the S phase of the cell cycle and is activated by DBF4. Here, we present crystal structures of a highly active human CDC7-DBF4 construct. The structures reveal a zinc-finger domain at the end of the kinase insert 2 that pins the CDC7 activation loop to motif M of DBF4 and the C lobe of CDC7. These interactions lead to ordering of the substrate-binding platform and full opening of the kinase active site. In a co-crystal structure with a mimic of MCM2 Ser40 phosphorylation target, the invariant CDC7 residues Arg373 and Arg380 engage phospho-Ser41 at substrate P+1 position, explaining the selectivity of the S-phase kinase for Ser/Thr residues followed by a pre-phosphorylated or an acidic residue. Our results clarify the role of DBF4 in activation of CDC7 and elucidate the structural basis for recognition of its preferred substrates. DBF4 activates CDC7 kinase via a two-step mechanism Zinc-finger domain in CDC7 KI2 interacts with DBF4 motif M Invariant CDC7 residues Arg373 and Arg380 engage P+1 substrate site
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5
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Yang CC, Kato H, Shindo M, Masai H. Cdc7 activates replication checkpoint by phosphorylating the Chk1-binding domain of Claspin in human cells. eLife 2019; 8:50796. [PMID: 31889509 PMCID: PMC6996922 DOI: 10.7554/elife.50796] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/30/2019] [Indexed: 01/05/2023] Open
Abstract
Replication checkpoint is essential for maintaining genome integrity in response to various replication stresses as well as during the normal growth. The evolutionally conserved ATR-Claspin-Chk1 pathway is induced during replication checkpoint activation. Cdc7 kinase, required for initiation of DNA replication at replication origins, has been implicated in checkpoint activation but how it is involved in this pathway has not been known. Here, we show that Cdc7 is required for Claspin-Chk1 interaction in human cancer cells by phosphorylating CKBD (Chk1-binding-domain) of Claspin. The residual Chk1 activation in Cdc7-depleted cells is lost upon further depletion of casein kinase1 (CK1γ1), previously reported to phosphorylate CKBD. Thus, Cdc7, in conjunction with CK1γ1, facilitates the interaction between Claspin and Chk1 through phosphorylating CKBD. We also show that, whereas Cdc7 is predominantly responsible for CKBD phosphorylation in cancer cells, CK1γ1 plays a major role in non-cancer cells, providing rationale for targeting Cdc7 for cancer cell-specific cell killing.
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Affiliation(s)
- Chi-Chun Yang
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hiroyuki Kato
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mayumi Shindo
- Protein Analyses Laboratory, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hisao Masai
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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6
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Abstract
The conserved serine-threonine kinase, Cdc7, plays a crucial role in initiation of DNA replication by facilitating the assembly of an initiation complex. Cdc7 is expressed at a high level and exhibits significant kinase activity not only during S-phase but also during G2/M-phases. A conserved mitotic kinase, Aurora B, is activated during M-phase by association with INCENP, forming the chromosome passenger complex with Borealin and Survivin. We show that Cdc7 phosphorylates and stimulates Aurora B kinase activity in vitro. We identified threonine-236 as a critical phosphorylation site on Aurora B that could be a target of Cdc7 or could be an autophosphorylation site stimulated by Cdc7-mediated phosphorylation elsewhere. We found that threonines at both 232 (that has been identified as an autophosphorylation site) and 236 are essential for the kinase activity of Aurora B. Cdc7 down regulation or inhibition reduced Aurora B activity in vivo and led to retarded M-phase progression. SAC imposed by paclitaxel was dramatically reversed by Cdc7 inhibition, similar to the effect of Aurora B inhibition under the similar situation. Our data show that Cdc7 contributes to M-phase progression and to spindle assembly checkpoint most likely through Aurora B activation.
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7
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Sasi NK, Bhutkar A, Lanning NJ, MacKeigan JP, Weinreich M. DDK Promotes Tumor Chemoresistance and Survival via Multiple Pathways. Neoplasia 2017; 19:439-450. [PMID: 28448802 PMCID: PMC5406526 DOI: 10.1016/j.neo.2017.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 12/12/2022] Open
Abstract
DBF4-dependent kinase (DDK) is a two-subunit kinase required for initiating DNA replication at individual origins and is composed of CDC7 kinase and its regulatory subunit DBF4. Both subunits are highly expressed in many diverse tumor cell lines and primary tumors, and this is correlated with poor prognosis. Inhibiting DDK causes apoptosis of tumor cells, but not normal cells, through a largely unknown mechanism. Firstly, to understand why DDK is often overexpressed in tumors, we identified gene expression signatures that correlate with DDK high- and DDK low-expressing lung adenocarcinomas. We found that increased DDK expression is highly correlated with inactivation of RB1-E2F and p53 tumor suppressor pathways. Both CDC7 and DBF4 promoters bind E2F, suggesting that increased E2F activity in RB1 mutant cancers promotes increased DDK expression. Surprisingly, increased DDK expression levels are also correlated with both increased chemoresistance and genome-wide mutation frequencies. Our data further suggest that high DDK levels directly promote elevated mutation frequencies. Secondly, we performed an RNAi screen to investigate how DDK inhibition causes apoptosis of tumor cells. We identified 23 kinases and phosphatases required for apoptosis when DDK is inhibited. These hits include checkpoint genes, G2/M cell cycle regulators, and known tumor suppressors leading to the hypothesis that inhibiting mitotic progression can protect against DDKi-induced apoptosis. Characterization of one novel hit, the LATS2 tumor suppressor, suggests that it promotes apoptosis independently of the upstream MST1/2 kinases in the Hippo signaling pathway.
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Affiliation(s)
- Nanda Kumar Sasi
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI 49503; Laboratory of Systems Biology, VARI; Graduate Program in Genetics, Michigan State University, East Lansing, MI 48824
| | - Arjun Bhutkar
- David H. Koch Institute for Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | - Michael Weinreich
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI 49503.
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8
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Discovery of novel furanone derivatives as potent Cdc7 kinase inhibitors. Eur J Med Chem 2017; 130:406-418. [PMID: 28279847 DOI: 10.1016/j.ejmech.2017.02.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/09/2017] [Accepted: 02/11/2017] [Indexed: 11/24/2022]
Abstract
Cdc7 is a serine-threonine kinase and plays a conserved and important role in DNA replication, and it has been recognized as a potential anticancer target. Herein, we report the design, synthesis and structure-activity relationship of novel furanone derivatives as Cdc7 kinase inhibitors. Compound 13 was identified as a strong inhibitor of Cdc7 with an IC50 value of 0.6 nM in the presence of 1 mM ATP and showed excellent kinase selectivity. In addition, it exhibited slow off-rate characteristics, which may offer advantages over known Cdc7 inhibitors in its potential to yield prolonged inhibitory effects in vivo. Compound 13 potently inhibited Cdc7 activity in cancer cells, and effectively induced cell death.
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9
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Lu S, Török HP, Gallmeier E, Kolligs FT, Rizzani A, Arena S, Göke B, Gerbes AL, De Toni EN. Tivantinib (ARQ 197) affects the apoptotic and proliferative machinery downstream of c-MET: role of Mcl-1, Bcl-xl and Cyclin B1. Oncotarget 2015; 6:22167-78. [PMID: 26259250 PMCID: PMC4673154 DOI: 10.18632/oncotarget.4240] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/28/2015] [Indexed: 01/11/2023] Open
Abstract
Tivantinib, a c-MET inhibitor, is investigated as a second-line treatment of HCC. It was shown that c-MET overexpression predicts its efficacy. Therefore, a phase-3 trial of tivantinib has been initiated to recruit "c-MET-high" patients only. However, recent evidence indicates that the anticancer activity of tivantinib is not due to c-MET inhibition, suggesting that c-MET is a predictor of response to this compound rather than its actual target. By assessing the mechanisms underlying the anticancer properties of tivantinib we showed that this agent causes apoptosis and cell cycle arrest by inhibiting the anti-apoptotic molecules Mcl-1 and Bcl-xl, and by increasing Cyclin B1 expression regardless of c-MET status. However, we found that tivantinib might antagonize the antiapoptotic effects of c-MET activation since HGF enhanced the expression of Mcl-1 and Bcl-xl. In summary, we show that the activity of tivantinib is independent of c-MET and describe Mcl-1, Bcl-xl and Cyclin B1 as effectors of its antineoplastic effects in HCC cells. We suggest that the predictive effect of c-MET expression in part reflects the c-MET-driven overexpression of Mcl-1 and Bcl-xl in c-MET-high patients and that these molecules are considered as possible response predictors.
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Affiliation(s)
- Shuai Lu
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
| | - Helga-Paula Török
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
| | - Eike Gallmeier
- Department of Gastroenterology, Endocrinology and Metabolism, University Hospital of Marburg, Philipps-University of Marburg, Marburg, Germany
| | - Frank T Kolligs
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
- Department of Internal Medicine and Gastroenterology, HELIOS Klinikum Berlin-Buch, Berlin, Germany
| | - Antonia Rizzani
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
| | - Sabrina Arena
- Department of Oncology, University of Torino, Candiolo, Torino, Italy
- Candiolo Cancer Institute-FPO, IRCCS, Candiolo, Italy
| | - Burkhard Göke
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
| | - Alexander L Gerbes
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
| | - Enrico N De Toni
- Medizinische Klinik und Poliklinik 2, Klinikum der Universität München, Campus Grosshadern, Munich, Germany
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10
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Bruce CD, Ferrara MM, Manka JL, Davis ZS, Register J. Dynamic hydrogen bonding and DNA flexibility in minor groove binders: molecular dynamics simulation of the polyamide f-ImPyIm bound to the Mlu1 (MCB) sequence 5'-ACGCGT-3' in 2:1 motif. J Mol Recognit 2015; 28:325-37. [PMID: 25711379 DOI: 10.1002/jmr.2448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 10/10/2014] [Accepted: 11/09/2014] [Indexed: 12/28/2022]
Abstract
Molecular dynamics simulations of the DNA 10-mer 5'-CCACGCGTGG-3' alone and complexed with the formamido-imidazole-pyrrole-imidazole (f-ImPyIm) polyamide minor groove binder in a 2:1 fashion were conducted for 50 ns using the pbsc0 parameters within the AMBER 12 software package. The change in DNA structure upon binding of f-ImPyIm was evaluated via minor groove width and depth, base pair parameters of Slide, Twist, Roll, Stretch, Stagger, Opening, Propeller, and x-displacement, dihedral angle distributions of ζ, ε, α, and γ determined using the Curves+ software program, and hydrogen bond formation. The dynamic hydrogen bonding between the f-ImPyIm and its cognate DNA sequence was compared to the static image used to predict sequence recognition by polyamide minor groove binders. Many of the predicted hydrogen bonds were present in less than 50% of the simulation; however, persistent hydrogen bonds between G5/15 and the formamido group of f-ImPyIm were observed. It was determined that the DNA is wider in the Complex than without the polyamide binder; however, there is flexibility in this particular sequence, even in the presence of the f-ImPyIm as evidenced by the range of minor groove widths the DNA exhibits and the dynamics of the hydrogen bonding that binds the two f-ImPyIm ions to the minor groove. The Complex consisting of the DNA and the 2 f-ImPyIm binders shows slight fraying of the 5' end of the 10-mer at the end of the simulation, but the portion of the oligomer responsible for recognition and binding is stable throughout the simulation. Several structural changes in the Complex indicate that minor groove binders may have a more active role in inhibiting transcription than just preventing binding of important transcription factors.
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Affiliation(s)
- Chrystal D Bruce
- Department of Chemistry, John Carroll University, 1 John Carroll Boulevard, University Heights, OH, 44118, USA
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11
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Sasi NK, Tiwari K, Soon FF, Bonte D, Wang T, Melcher K, Xu HE, Weinreich M. The potent Cdc7-Dbf4 (DDK) kinase inhibitor XL413 has limited activity in many cancer cell lines and discovery of potential new DDK inhibitor scaffolds. PLoS One 2014; 9:e113300. [PMID: 25412417 PMCID: PMC4239038 DOI: 10.1371/journal.pone.0113300] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/23/2014] [Indexed: 12/16/2022] Open
Abstract
Cdc7-Dbf4 kinase or DDK (Dbf4-dependent kinase) is required to initiate DNA replication by phosphorylating and activating the replicative Mcm2-7 DNA helicase. DDK is overexpressed in many tumor cells and is an emerging chemotherapeutic target since DDK inhibition causes apoptosis of diverse cancer cell types but not of normal cells. PHA-767491 and XL413 are among a number of potent DDK inhibitors with low nanomolar IC50 values against the purified kinase. Although XL413 is highly selective for DDK, its activity has not been extensively characterized on cell lines. We measured anti-proliferative and apoptotic effects of XL413 on a panel of tumor cell lines compared to PHA-767491, whose activity is well characterized. Both compounds were effective biochemical DDK inhibitors but surprisingly, their activities in cell lines were highly divergent. Unlike PHA-767491, XL413 had significant anti-proliferative activity against only one of the ten cell lines tested. Since XL413 did not effectively inhibit DDK in multiple cell lines, this compound likely has limited bioavailability. To identify potential leads for additional DDK inhibitors, we also tested the cross-reactivity of ∼400 known kinase inhibitors against DDK using a DDK thermal stability shift assay (TSA). We identified 11 compounds that significantly stabilized DDK. Several inhibited DDK with comparable potency to PHA-767491, including Chk1 and PKR kinase inhibitors, but had divergent chemical scaffolds from known DDK inhibitors. Taken together, these data show that several well-known kinase inhibitors cross-react with DDK and also highlight the opportunity to design additional specific, biologically active DDK inhibitors for use as chemotherapeutic agents.
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Affiliation(s)
- Nanda Kumar Sasi
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI, United States of America
- Graduate Program in Genetics, Michigan State University, East Lansing, MI, United States of America
| | - Kanchan Tiwari
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI, United States of America
| | - Fen-Fen Soon
- Laboratory of Structural Sciences, VARI, Grand Rapids, MI, United States of America
| | - Dorine Bonte
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI, United States of America
| | - Tong Wang
- Translational Drug Development, Inc. (TD2), Scottsdale, AZ, United States of America
| | - Karsten Melcher
- Laboratory of Structural Biology and Biochemistry, VARI, Grand Rapids, MI, United States of America
| | - H. Eric Xu
- Laboratory of Structural Sciences, VARI, Grand Rapids, MI, United States of America
| | - Michael Weinreich
- Laboratory of Genome Integrity and Tumorigenesis, Van Andel Research Institute (VARI), Grand Rapids, MI, United States of America
- * E-mail:
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12
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Lian X, Wang H, Wei X, Wang Y, Wang Q, Guo L, Zhao Y, Chen X. BMI‑1 is important in bufalin‑induced apoptosis of K562 cells. Mol Med Rep 2014; 9:1209-17. [PMID: 24566825 DOI: 10.3892/mmr.2014.1980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 01/23/2014] [Indexed: 11/06/2022] Open
Abstract
The purpose of this study was to analyze the effects of bufalin on the gene expression of K562 cells and on the expression of BMI‑1 pathway constituents in K562 cell apoptosis. K562 cells were treated with bufalin, and the inhibition rate and apoptosis were detected by an MTT assay, flow cytometry and a microarray assay. BMI‑1, p16INK4a and p14ARF were examined by quantitative polymerase chain reaction (qPCR). Bufalin induced significant changes in the gene expression of the K562 cells; 4296 genes were differentially expressed, 2185 were upregulated and 2111 were downregulated. The most upregulated genes were associated with transcription regulation, while the most downregulated genes were associated with the non-coding RNA metabolic processes and DNA repair. qPCR analysis demonstrated that BMI‑1 was overexpressed in the K562 cells. Bufalin is able to downregulate BMI‑1 expression levels in K562 cells prematurely and cause an increase in the expression levels of p16INK4a and p14ARF. Moreover, bufalin downregulated BCR/ABL expression levels in a time‑dependent manner, and the expression of BCR/ABL was not associated with the upregulation or downregulation of BMI‑1 expression. Bufalin may induce K562 cell apoptosis by downregulating BMI‑1 expression levels and accordingly upregulating the expression levels of p16INK4a and p14ARF. Bufalin may also induce K562 cell apoptosis via downregulating BCR/ABL expression levels, and this pathway may be independent of the BMI‑1 pathway.
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Affiliation(s)
- Xiaoyun Lian
- Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Hao Wang
- Department of Hematology, Xi'an Central Hospital, Xi'an, Shaanxi 710003, P.R. China
| | - Xucang Wei
- Department of Hematology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Yi Wang
- Department of Hematology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Qishan Wang
- Department of Hematology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Liang Guo
- Department of Hematology, Xi'an Central Hospital, Xi'an, Shaanxi 710003, P.R. China
| | - Yuan Zhao
- Department of Hematology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Xiequn Chen
- Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
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Cheng AN, Jiang SS, Fan CC, Lo YK, Kuo CY, Chen CH, Liu YL, Lee CC, Chen WS, Huang TS, Wang TY, Lee AYL. Increased Cdc7 expression is a marker of oral squamous cell carcinoma and overexpression of Cdc7 contributes to the resistance to DNA-damaging agents. Cancer Lett 2013; 337:218-25. [PMID: 23684929 DOI: 10.1016/j.canlet.2013.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 05/07/2013] [Accepted: 05/09/2013] [Indexed: 01/28/2023]
Abstract
Cdc7-Dbf4 kinase (Dbf4-dependent kinase, DDK) is an essential factor of DNA replication and DNA damage response (DDR), which is associated with tumorigenesis. However, Cdc7 expression has never been associated to the outcome of oral squamous cell carcinoma (OSCC) patients, and the mechanism underlying cancer cell survival mediated by Cdc7 remains unclear. The Cdc7 protein expression of 105 OSCC tumor and 30 benign tissues was examined by immunohistochemistry assay. Overall survival rates of 80 OSCC patients were measured using Kaplan-Meier estimates and the log-rank tests. Cdc7 overexpression by adenovirus system was used to scrutinize the underlying mechanism contributed to cancer cell survival upon DDR. In silico analysis showed that increased Cdc7 is a common feature of cancer. Cdc7 overexpression was found in 96 of 105 (91.4%) studied cases of OSCC patients. Patients with higher Cdc7 expression, either categorized into two groups: Cdc7 high expression (2+ to 3+) versus Cdc7 low expression (0 to 1+) [hazard ratios (HR)=2.6; 95% confidence interval (CI)=1.28-5.43; P=0.0087] or four groups (0 to 3+) [HR=1.71; 95% CI=1.20-2.44; P=0.0032], exhibited a poorer outcome. Multivariate analysis showed that Cdc7 is an independent marker for survival prediction. Overexpressed Cdc7 inhibits genotoxin-induced apoptosis to increase the survival of cancer cells. In summary, Cdc7 expression, which is universally upregulated in cancer, is an independent prognostic marker of OSCC. Cdc7 inhibits genotoxin-induced apoptosis and increases survival in cancer cells upon DDR, suggesting that high expression of Cdc7 enhances the resistance to chemotherapy.
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Affiliation(s)
- An Ning Cheng
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Miaoli, Taiwan
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Yamazaki S, Ishii A, Kanoh Y, Oda M, Nishito Y, Masai H. Rif1 regulates the replication timing domains on the human genome. EMBO J 2012; 31:3667-77. [PMID: 22850674 DOI: 10.1038/emboj.2012.180] [Citation(s) in RCA: 182] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 06/13/2012] [Indexed: 11/09/2022] Open
Abstract
DNA replication is spatially and temporally regulated during S-phase. DNA replication timing is established in early-G1-phase at a point referred to as timing decision point. However, how the genome-wide replication timing domains are established is unknown. Here, we show that Rif1 (Rap1-interacting-factor-1), originally identified as a telomere-binding factor in yeast, is a critical determinant of the replication timing programme in human cells. Depletion of Rif1 results in specific loss of mid-S replication foci profiles, stimulation of initiation events in early-S-phase and changes in long-range replication timing domain structures. Analyses of replication timing show replication of sequences normally replicating early is delayed, whereas that normally replicating late is advanced, suggesting that replication timing regulation is abrogated in the absence of Rif1. Rif1 tightly binds to nuclear-insoluble structures at late-M-to-early-G1 and regulates chromatin-loop sizes. Furthermore, Rif1 colocalizes specifically with the mid-S replication foci. Thus, Rif1 establishes the mid-S replication domains that are restrained from being activated at early-S-phase. Our results indicate that Rif1 plays crucial roles in determining the replication timing domain structures in human cells through regulating higher-order chromatin architecture.
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Affiliation(s)
- Satoshi Yamazaki
- Genome Dynamics Project, Department of Genome Medicine, Tokyo, Japan
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