Publications by authors named "Takehiko Dohi"

28 Publications

  • Page 1 of 1

Is there increased risk of hepatocellular carcinoma recurrence in liver transplant patients with direct-acting antiviral therapy?

Hepatol Int 2019 Mar 24;13(2):190-198. Epub 2019 Jan 24.

Division of Transplantation, Department of Surgery, College of Medicine, Pennsylvania State University, Mail Code H062, 500 University Drive, PO Box 850, Hershey, PA, 17033-0850, USA.

Background: Recently, a controversy has emerged: is the rate of recurrence of hepatocellular carcinoma (HCC) higher following treatment of hepatitis C virus (HCV) with direct-acting antiviral (DAA) therapy? However, the risk of HCC recurrence has not been studied in liver transplant (LTx) recipients who received DAA therapy. The aim of the present study is to compare the rate of HCC recurrence in LTx recipients who did or did not receive DAA therapy.

Patients And Methods: Sixty-three patients received LTx with HCC. Twenty-seven (42.9%) with HCV received DAA therapy (Group A), 20 (31.7%) with HCV did not receive DAA therapy (Group B), and 16 (25.4%) did not have HCV (Group C).

Results: In group A, three (11%), in group B, one (5%), and in group C, none had recurrence of HCC. Actuarial 4-year recurrence-free survival was 88.9, 95, and 100% in group A, B, and C, respectively (p = 0.37). Group A was subdivided into two groups for comparison with Group B: A1 included five patients who had end of treatment response (ETR) without sustained virological response (SVR), and A2 included 20 patients who achieved SVR. Three patients from A1 had HCC recurrence and no patients from A2 had HCC recurrence. (p = 0.0038; group A1, A2, and B).

Conclusions: The rate of HCC recurrence in LTx patients with DAA therapy was significantly higher with ETR, without SVR, after DAA therapy compared to patients with SVR or patients who did not receive DAA therapy. LTx recipients with HCC receiving DAA therapy requires further studies.
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http://dx.doi.org/10.1007/s12072-019-09930-xDOI Listing
March 2019

Incidence of Post-Liver Transplant Hepatic Dysfunction After Sustained Virologic Response Following Direct-Acting Anti-Hepatitis C Therapy.

Exp Clin Transplant 2020 06 5;18(3):345-352. Epub 2018 Oct 5.

From the Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA.

Objectives: Newly developed, direct-acting antiviral therapy is effective in over 90% of cases to eradicate hepatitis C virus infection. Direct-acting antiviral therapy is also effective in liver transplant recipients with recurrent hepatitis C virus infection. However, hepatic function after sustained virologic response in transplant recipients is unknown. Here, we aimed to uncover the incidence of hepatic dysfunction in this patient group at our center.

Materials And Methods: Our study included 40 consecutive (January 2014 to February 2016) and compliant posttransplant recipients who achieved sustained viral response from direct-acting antiviral therapy. Patients were investigated for incidence and causes of hepatic dysfunction.

Results: In our patient group, 4 (10%) experienced hepatic dysfunction with stable baseline immunosuppression, with 2 having drastic increases in alanine aminotransferase at 15 and 32 weeks after direct-acting antiviral therapy. Biopsies showed hepatitis, and both patients were treated with hydrocortisone, which increased their baseline immunosuppression. The 3rd patient had an increase in bilirubin at 21 weeks posttherapy, with biopsy showing macrovascular steatosis. The 4th patient had a rapid increase in bilirubin at 7 weeks after direct-acting antiviral therapy, with biopsy showing significant duct loss.

Conclusions: During the study period, 10% of patients experienced hepatic dysfunction after sustained viral response. Presumed causative factors included partial immune reconstitution and nonalcoholic fatty liver disease.
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http://dx.doi.org/10.6002/ect.2018.0127DOI Listing
June 2020

Everolimus with low-dose tacrolimus in simultaneous pancreas and kidney transplantation.

Clin Transplant 2014 Jul 1;28(7):797-801. Epub 2014 Jun 1.

Division of Kidney and Pancreas Transplantation, Dewitt Daughtry Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Miami Transplant Institute at the Jackson Memorial Hospital and University of Miami, Miami, FL, USA.

The efficacy and safety of everolimus (EVR) in simultaneous pancreas and kidney transplantation (SPKT) is unclear. We retrospectively evaluated 25 consecutive SPKT recipients at our center from November 2011 to March 2013. All patients received dual induction (Thymoglobulin/basiliximab) and low-dose tacrolimus plus corticosteroids. Nine patients who received EVR were compared with 14 patients who received enteric-coated mycophenolate sodium (EC-MPS); two patients who received sirolimus were excluded from the analysis. With a median follow-up of 14 months, the pancreas graft survival rate was 100% in both groups, and the kidney graft survival rate was 100% and 93% in EVR and EC-MPS patients, respectively. One EC-MPS patient lost her kidney graft from proteinuric kidney disease. Another EC-MPS patient received treatment for clinically diagnosed pancreas and kidney graft rejection. No rejection was observed in EVR patients. Serum creatinine and HbA1c levels were similar between the groups. There was no significant difference of surgical or medical complications. In conclusion, EVR seems to provide comparable short-term outcome to EC-MPS when combined with low-dose tacrolimus/steroids and dual induction therapy. A larger study with a longer follow-up is required to further assess this combination.
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http://dx.doi.org/10.1111/ctr.12381DOI Listing
July 2014

Lack of clinical association and effect of peripheral WBC counts on immune cell function test in kidney transplant recipients with T-cell depleting induction and steroid-sparing maintenance therapy.

Transpl Immunol 2014 Mar 9;30(2-3):88-92. Epub 2014 Feb 9.

Division of Kidney and Pancreas Transplantation, Dewitt Daughtry Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Miami Transplant Institute at the Jackson Memorial Hospital and University of Miami, Miami, FL, USA.

The Cylex ImmuKnow assay measures the amount of stimulated ATP production by CD4+ T-cells, and has been used clinically, trying to predict rejection and infection episodes. However, predictive values of this assay after induction therapy with steroid-sparing maintenance protocols are unclear. In this single-center cohort study, we analyzed renal transplant recipients who received T-cell depleting+/-anti-IL2 receptor antibodies and tacrolimus/mycophenolate maintenance without steroids. A total of 4224 ImmuKnow levels in 306 patients were available for analysis. ImmuKnow levels (Mean ± SE) changed over time after induction therapy with a paradoxical initial increase: 419 ± 23, 461 ± 32, 519 ± 14, 411 ± 10, 344 ± 6, and 405 ± 3 for pre-transplant, 0-1 wk, 1 wk-1 mo, 1-3 mos, 3 mos-1 yr, and thereafter. This change was parallel to the evolution of peripheral WBC counts and ImmuKnow levels had weak but significant correlation with WBC counts (R(2)=0.264, P<0.0001). The levels for biopsy-proven rejection (389 ± 56) and borderline/clinical rejection (254 ± 41) were not significantly higher than the levels of quiescent patients. The levels for opportunistic infection (349 ± 48) and other infections (345 ± 27) were not significantly lower than the levels of quiescent patients. The longitudinal changes in ImmuKnow levels were not predictive of rejection or infection. In conclusion, ImmuKnow levels can vary after T-cell depleting induction therapies at various time points, even without significant clinical events. Since ImmuKnow levels seem to be affected by WBC counts, ImmuKnow results need to be interpreted with caution. The effects of leukocytosis or leukopenia caused by immunosuppressive medication on the ImmuKnow assay need further investigation.
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http://dx.doi.org/10.1016/j.trim.2014.01.003DOI Listing
March 2014

Control of tumor bioenergetics and survival stress signaling by mitochondrial HSP90s.

Cancer Cell 2012 Sep;22(3):331-44

Prostate Cancer Discovery and Development Program, The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.

Tumors successfully adapt to constantly changing intra- and extracellular environments, but the wirings of this process are still largely elusive. Here, we show that heat-shock-protein-90-directed protein folding in mitochondria, but not cytosol, maintains energy production in tumor cells. Interference with this process activates a signaling network that involves phosphorylation of nutrient-sensing AMP-activated kinase, inhibition of rapamycin-sensitive mTOR complex 1, induction of autophagy, and expression of an endoplasmic reticulum unfolded protein response. This signaling network confers a survival and proliferative advantage to genetically disparate tumors, and correlates with worse outcome in lung cancer patients. Therefore, mitochondrial heat shock protein 90s are adaptive regulators of tumor bioenergetics and tractable targets for cancer therapy.
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http://dx.doi.org/10.1016/j.ccr.2012.07.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3615709PMC
September 2012

Chk2 phosphorylation of survivin-DeltaEx3 contributes to a DNA damage-sensing checkpoint in cancer.

Cancer Res 2012 Jul 14;72(13):3251-9. Epub 2012 May 14.

Prostate Cancer Discovery and Development Program, Center for Systems and Computational Biology, The Wistar Institute, Philadelphia, Pennsylvania 19104, USA.

Survivin is an oncogene that functions in cancer cell cytoprotection and mitosis. Here we report that differential expression in cancer cells of a C-terminal splice variant of survivin, termed survivin-ΔEx3, is tightly associated with aggressive disease and markers of unfavorable prognosis. In contrast to other survivin variants, survivin-ΔEx3 localized exclusively to nuclei in tumor cells and was phosphorylated at multiple residues by the checkpoint kinase Chk2 during DNA damage. Mutagenesis of the Chk2 phosphorylation sites enhanced the stability of survivin-ΔEx3 in tumor cells, inhibited the expression of phosphorylated H2AX (γH2AX) in response to double-strand DNA breaks, and impaired growth after DNA damage. DNA damage induced Chk2 phosphorylation, stabilization of p53, induction of the cyclin-dependent kinase inhibitor p21, and homologous recombination-induced repair were not affected. In vivo, active Chk2 was detected at the earliest stages of the colorectal adenoma-to-carcinoma transition, persisted in advanced tumors, and correlated with increased survivin expression. Together, our findings suggest that Chk2-mediated phosphorylation of survivin-ΔEx3 contributes to a DNA damage-sensing checkpoint that may affect cancer cell sensitivity to genotoxic therapies.
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http://dx.doi.org/10.1158/0008-5472.CAN-11-4035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3695608PMC
July 2012

Essential role of the small GTPase Ran in postnatal pancreatic islet development.

PLoS One 2011 17;6(11):e27879. Epub 2011 Nov 17.

Prostate Cancer Discovery and Development Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America.

The small GTPase Ran orchestrates pleiotropic cellular responses of nucleo-cytoplasmic shuttling, mitosis and subcellular trafficking, but whether deregulation of these pathways contributes to disease pathogenesis has remained elusive. Here, we generated transgenic mice expressing wild type (WT) Ran, loss-of-function Ran T24N mutant or constitutively active Ran G19V mutant in pancreatic islet β cells under the control of the rat insulin promoter. Embryonic pancreas and islet development, including emergence of insulin(+) β cells, was indistinguishable in control or transgenic mice. However, by one month after birth, transgenic mice expressing any of the three Ran variants exhibited overt diabetes, with hyperglycemia, reduced insulin production, and nearly complete loss of islet number and islet mass, in vivo. Deregulated Ran signaling in transgenic mice, adenoviral over-expression of WT or mutant Ran in isolated islets, or short hairpin RNA (shRNA) silencing of endogenous Ran in model insulinoma INS-1 cells, all resulted in decreased expression of the pancreatic and duodenal homeobox transcription factor, PDX-1, and reduced β cell proliferation, in vivo. These data demonstrate that a finely-tuned balance of Ran GTPase signaling is essential for postnatal pancreatic islet development and glucose homeostasis, in vivo.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0027879PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3219697PMC
May 2012

Aberrant overexpression of the cell polarity module scribble in human cancer.

Am J Pathol 2011 Jun 6;178(6):2478-83. Epub 2011 May 6.

Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.

Human Scribble (Scrib) is an evolutionary-conserved cell polarity protein, but its potential role in human cancer is controversial. Herein, we show that Scrib is nearly universally overexpressed in cultured tumor cell lines and genetically disparate cancer patient series compared with matched normal tissues in vivo. Instead of a membrane association seen in normal epithelia, tumor-associated Scrib is mislocalized and found predominantly in the cytosol. Small-interfering RNA silencing of Scrib in model lung adenocarcinoma A549 cells inhibited cell migration in wound-healing assays, suppressed tumor cell invasion across Matrigel-coated inserts, and down-regulated the expression of cell motility markers and mediators of epithelial-mesenchymal transition. These data uncover a previously unrecognized exploitation of Scrib for aberrant tumor cell motility and invasion, thus potentially contributing to disease progression in humans.
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http://dx.doi.org/10.1016/j.ajpath.2011.02.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124121PMC
June 2011

Developmental control of apoptosis by the immunophilin aryl hydrocarbon receptor-interacting protein (AIP) involves mitochondrial import of the survivin protein.

J Biol Chem 2011 May 18;286(19):16758-67. Epub 2011 Mar 18.

Prostate Cancer Discovery and Development Program, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

Survivin is a multifunctional protein with essential roles in cell division and inhibition of apoptosis, but the molecular underpinnings of its cytoprotective properties are poorly understood. Here we show that homozygous deletion of the aryl hydrocarbon receptor-interacting protein (AIP), a survivin-associated immunophilin, causes embryonic lethality in mice by embryonic day 13.5-14, increased apoptosis of Ter119(-)/CD71(-) early erythropoietic progenitors, and loss of survivin expression in its cytosolic and mitochondrial compartments in vivo. In import assays using recombinant proteins, AIP directly mediated the import of survivin to mitochondria, thus enabling its anti-apoptotic function, whereas a survivin 1-141 mutant that does not bind AIP was not imported to mitochondria and failed to inhibit apoptosis. AIP-directed mitochondrial import of survivin did not affect cell division, was independent of the organelle transmembrane potential, did not require the chaperone Heat Shock Protein 90 (Hsp90), and was inhibited by cytosolic factor(s) present in normal cells. shRNA knockdown of the mitochondrial import receptor Tom20 abolished mitochondrial import of survivin and sensitized tumor cells to apoptosis, whereas silencing of Tom70 had no effect. Therefore, an AIP-Tom20 recognition contributes to cell survival in development and cancer by mediating the mitochondrial import of survivin.
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http://dx.doi.org/10.1074/jbc.M110.210120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3089518PMC
May 2011

Exploiting the mitochondrial unfolded protein response for cancer therapy in mice and human cells.

J Clin Invest 2011 Apr;121(4):1349-60

Prostate Cancer Discovery and Development Program, Philadelphia, Pennsylvania, USA.

Fine tuning of the protein folding environment in subcellular organelles, such as mitochondria, is important for adaptive homeostasis and may participate in human diseases, but the regulators of this process are still largely elusive. Here, we have shown that selective targeting of heat shock protein-90 (Hsp90) chaperones in mitochondria of human tumor cells triggered compensatory autophagy and an organelle unfolded protein response (UPR) centered on upregulation of CCAAT enhancer binding protein (C/EBP) transcription factors. In turn, this transcriptional UPR repressed NF-κB-dependent gene expression, enhanced tumor cell apoptosis initiated by death receptor ligation, and inhibited intracranial glioblastoma growth in mice without detectable toxicity. These data reveal what we believe to be a novel role of Hsp90 chaperones in the regulation of the protein-folding environment in mitochondria of tumor cells. Disabling this general adaptive pathway could potentially be used in treatment of genetically heterogeneous human tumors.
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http://dx.doi.org/10.1172/JCI44855DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3069780PMC
April 2011

Heat shock protein 60 regulation of the mitochondrial permeability transition pore in tumor cells.

Cancer Res 2010 Nov 26;70(22):8988-93. Epub 2010 Oct 26.

Prostate Cancer Discovery and Development Program, The Wistar Institute Cancer Center, Philadelphia, Pennsylvania 19104, USA.

Mitochondrial apoptosis plays a critical role in tumor maintenance and dictates the response to therapy in vivo; however, the regulators of this process are still largely elusive. Here, we show that the molecular chaperone heat shock protein 60 (Hsp60) directly associates with cyclophilin D (CypD), a component of the mitochondrial permeability transition pore. This interaction occurs in a multichaperone complex comprising Hsp60, Hsp90, and tumor necrosis factor receptor-associated protein-1, selectively assembled in tumor but not in normal mitochondria. Genetic targeting of Hsp60 by siRNA triggers CypD-dependent mitochondrial permeability transition, caspase-dependent apoptosis, and suppression of intracranial glioblastoma growth in vivo. Therefore, Hsp60 is a novel regulator of mitochondrial permeability transition, contributing to a cytoprotective chaperone network that antagonizes CypD-dependent cell death in tumors.
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http://dx.doi.org/10.1158/0008-5472.CAN-10-2225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982903PMC
November 2010

Preclinical characterization of mitochondria-targeted small molecule hsp90 inhibitors, gamitrinibs, in advanced prostate cancer.

Clin Cancer Res 2010 Oct 28;16(19):4779-88. Epub 2010 Sep 28.

Department of Cancer Biology, University of Massachusetts Medical School, Worcester, USA.

Purpose: This study aimed to characterize the preclinical activity of the first class of combinatorial, mitochondria-targeted, small molecule heat shock protein-90 (Hsp90) inhibitors, gamitrinibs, in models of hormone-refractory, drug-resistant, localized, and bone metastatic prostate cancer in vivo.

Experimental Design: Mitochondrial permeability transition, apoptosis, and changes in metabolic activity were examined by time-lapse videomicroscopy, multiparametric flow cytometry, MTT, and analysis of isolated mitochondria. Drug-resistant prostate cancer cells were generated by chronic exposure of hormone-refractory PC3 cells to the Hsp90 inhibitor 17-allylaminogeldanamycin (17-AAG). The effect of gamitrinibs on s.c. or intratibial prostate cancer growth was studied in xenograft models. Bone metastatic tumor growth and bone parameters were quantified by micro-computed tomography imaging.

Results: In the NCI 60-cell line screening, gamitrinibs were active against all tumor cell types tested, and efficiently killed metastatic, hormone-refractory, and multidrug-resistant prostate cancer cells characterized by overexpression of the ATP binding cassette transporter P-glycoprotein. Mechanistically, gamitrinibs, but not 17-AAG, induced acute mitochondrial dysfunction in prostate cancer cells with loss of organelle membrane potential, release of cytochrome c, and caspase activity, independently of proapoptotic Bcl-2 proteins Bax and Bak. Systemic administration of gamitrinibs to mice was well tolerated, and inhibited s.c. or bone metastatic prostate cancer growth in vivo.

Conclusions: Gamitrinibs have preclinical activity and favorable safety in models of drug-resistant and bone metastatic prostate cancer in vivo.
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http://dx.doi.org/10.1158/1078-0432.CCR-10-1818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948625PMC
October 2010

IAP regulation of metastasis.

Cancer Cell 2010 Jan;17(1):53-64

Department of Cancer Biology, Prostate Cancer Discovery and Development Program, University of Massachusetts Medical School, Worcester, MA 01605, USA.

Inhibitor-of-Apoptosis (IAP) proteins contribute to tumor progression, but the requirements of this pathway are not understood. Here, we show that intermolecular cooperation between XIAP and survivin stimulates tumor cell invasion and promotes metastasis. This pathway is independent of IAP inhibition of cell death. Instead, a survivin-XIAP complex activates NF-kappaB, which in turn leads to increased fibronectin gene expression, signaling by beta1 integrins, and activation of cell motility kinases FAK and Src. Therefore, IAPs are direct metastasis genes, and their antagonists could provide antimetastatic therapies in patients with cancer.
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http://dx.doi.org/10.1016/j.ccr.2009.11.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818597PMC
January 2010

Postnatal expansion of the pancreatic beta-cell mass is dependent on survivin.

Diabetes 2008 Oct 3;57(10):2718-27. Epub 2008 Jul 3.

The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA.

Objective: Diabetes results from a deficiency of functional beta-cells due to both an increase in beta-cell death and an inhibition of beta-cell replication. The molecular mechanisms responsible for these effects in susceptible individuals are mostly unknown. The objective of this study was to determine whether a gene critical for cell division and cell survival in cancer cells, survivin, might also be important for beta-cells.

Research Design And Methods: We generated mice harboring a conditional deletion of survivin in pancreatic endocrine cells using mice with a Pax-6-Cre transgene promoter construct driving tissue-specific expression of Cre-recombinase in these cells. We performed metabolic studies and immunohistochemical analyses to determine the effects of a mono- and biallelic deletion of survivin.

Results: Selective deletion of survivin in pancreatic endocrine cells in the mouse had no discernible effects during embryogenesis but was associated with striking decreases in beta-cell number after birth, leading to hyperglycemia and early-onset diabetes by 4 weeks of age. Serum insulin levels were significantly decreased in animals lacking endocrine cell survivin, with relative stability of other hormones. Exogenous expression of survivin in mature beta-cells lacking endogenous survivin completely rescued the hyperglycemic phenotype and the decrease in beta-cell mass, confirming the specificity of the survivin effect in these cells.

Conclusions: Our findings implicate survivin in the maintenance of beta-cell mass through both replication and antiapoptotic mechanisms. Given the widespread involvement of survivin in cancer, a novel role for survivin may well be exploited in beta-cell regulation in diseased states, such as diabetes.
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http://dx.doi.org/10.2337/db08-0170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2551682PMC
October 2008

Hsp60 regulation of tumor cell apoptosis.

J Biol Chem 2008 Feb 17;283(8):5188-94. Epub 2007 Dec 17.

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachustetts 01605, USA.

Molecular chaperones may promote cell survival, but how this process is regulated, especially in cancer, is not well understood. Using high throughput proteomics screening, we identified the cell cycle regulator and apoptosis inhibitor survivin as a novel protein associated with the molecular chaperone Hsp60. Acute ablation of Hsp60 by small interfering RNA destabilizes the mitochondrial pool of survivin, induces mitochondrial dysfunction, and activates caspase-dependent apoptosis. This response involves disruption of an Hsp60-p53 complex, which results in p53 stabilization, increased expression of pro-apoptotic Bax, and Bax-dependent apoptosis. In vivo, Hsp60 is abundantly expressed in primary human tumors, as compared with matched normal tissues, and small interfering RNA ablation of Hsp60 in normal cells is well tolerated and does not cause apoptosis. Therefore, Hsp60 orchestrates a broad cell survival program centered on stabilization of mitochondrial survivin and restraining of p53 function, and this process is selectively exploited in cancer. Hsp60 inhibitors may function as attractive anticancer agents by differentially inducing apoptosis in tumor cells.
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http://dx.doi.org/10.1074/jbc.M705904200DOI Listing
February 2008

Regulation of tumor cell mitochondrial homeostasis by an organelle-specific Hsp90 chaperone network.

Cell 2007 Oct;131(2):257-70

Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.

Molecular chaperones, especially members of the heat shock protein 90 (Hsp90) family, are thought to promote tumor cell survival, but this function is not well understood. Here, we show that mitochondria of tumor cells, but not most normal tissues, contain Hsp90 and its related molecule, TRAP-1. These chaperones interact with Cyclophilin D, an immunophilin that induces mitochondrial cell death, and antagonize its function via protein folding/refolding mechanisms. Disabling this pathway using novel Hsp90 ATPase antagonists directed to mitochondria causes sudden collapse of mitochondrial function and selective tumor cell death. Therefore, Hsp90-directed chaperones are regulators of mitochondrial integrity, and their organelle-specific antagonists may provide a previously undescribed class of potent anticancer agents.
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http://dx.doi.org/10.1016/j.cell.2007.08.028DOI Listing
October 2007

Compartmentalized phosphorylation of IAP by protein kinase A regulates cytoprotection.

Mol Cell 2007 Jul;27(1):17-28

Department of Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.

Cell death pathways are likely regulated in specialized subcellular microdomains, but how this occurs is not understood. Here, we show that cyclic AMP-dependent protein kinase A (PKA) phosphorylates the inhibitor of apoptosis (IAP) protein survivin on Ser20 in the cytosol, but not in mitochondria. This phosphorylation event disrupts the binding interface between survivin and its antiapoptotic cofactor, XIAP. Conversely, mitochondrial survivin or a non-PKA phosphorylatable survivin mutant binds XIAP avidly, enhances XIAP stability, synergistically inhibits apoptosis, and accelerates tumor growth, in vivo. Therefore, differential phosphorylation of survivin by PKA in subcellular microdomains regulates tumor cell apoptosis via its interaction with XIAP.
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http://dx.doi.org/10.1016/j.molcel.2007.06.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1986705PMC
July 2007

Activated checkpoint kinase 2 provides a survival signal for tumor cells.

Cancer Res 2006 Dec;66(24):11576-9

Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

Tumor cells often become resistant to DNA damage-based therapy; however, the underlying mechanisms are not yet understood. Here, we show that tumor cells exposed to DNA damage counteract cell death by releasing the antiapoptotic protein, survivin, from mitochondria. This is independent of p53, and requires activated checkpoint kinase 2 (Chk2), a putative tumor suppressor. Molecular or genetic targeting of Chk2 prevents the release of survivin from mitochondria, enhances DNA damage-induced tumor cell apoptosis, and inhibits the growth of resistant in vivo tumors. Therefore, activated Chk2 circumvents its own tumor-suppressive functions by promoting tumor cell survival. Inhibiting Chk2 in combination with DNA-damaging agents may provide a rational approach for treating resistant tumors.
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http://dx.doi.org/10.1158/0008-5472.CAN-06-3095DOI Listing
December 2006

Oncolytic recombinant herpes simplex virus for treatment of orthotopic liver tumors in nude mice.

Int J Oncol 2006 Apr;28(4):793-8

Department of General and Gastroenterological Surgery, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan.

Cell-specific, replicating viruses are being developed as a new class of oncolytic agents. A novel approach to viral gene therapy with the use of replication-competent herpes simplex virus has been described; G92A is a replication-competent, multimutant oncolytic herpes simplex virus (HSV) that has been evaluated for anticancer effects and selectivity in the treatment of subcutaneous tumors. G92A replicates efficiently in albumin-producing tumor cell lines but not in non-albumin-producing tumor cell lines, whereas both types are equally susceptible to a non-tissue-specific recombinant HSV, hrR3. In this study, we analyzed the antitumoral efficacy of a single intrasplenic G92A or hrR3 injection in nude mice. In vivo, G92A replicated well in liver xenografts of human albumin-producing hepatoma cells (Hep3B) but not in liver xenografts of a non-albumin-producing malignant colon tumor cell line (HT29), whereas hrR3 replicated well in both tumor types. G92A effectively and selectively replicated throughout liver tumors without apparent hepatotoxicity and inhibited tumor growth, leading to a significantly increased survival time. By monitoring lacZ histochemical staining, we determined the oncolytic potential of recombinant HSV against liver tumors. Our results indicate that G92A warrants further investigation as a clinical therapy against malignant liver tumors.
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April 2006

Inhibition of apoptosis by survivin improves transplantation of pancreatic islets for treatment of diabetes in mice.

EMBO Rep 2006 Apr 10;7(4):438-43. Epub 2006 Feb 10.

Department of Cancer Biology, University of Massachusetts Medical School, Worcester, 01605, USA.

Survivin is a cancer gene implicated in inhibition of apoptosis and regulation of mitosis, but its function in normal cells has remained elusive. Here, we show that transgenic mice expressing survivin in pancreatic islet beta-cells show no changes in cell proliferation, as determined by islet size or islet number. Transplantation of survivin transgenic islets in diabetic recipient mice affords long-term engraftment and stable correction of hyperglycaemia. This involves intrinsic inhibition of beta-cell apoptosis, in vivo, and global transcriptional changes in pancreatic islets with upregulation of stress response genes, antagonists of cytokine signalling and promoters of angiogenesis. These broad cytoprotective functions of survivin in vivo might be beneficial for gene therapy of diabetes.
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http://dx.doi.org/10.1038/sj.embor.7400640DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1456913PMC
April 2006

Rational design of shepherdin, a novel anticancer agent.

Cancer Cell 2005 May;7(5):457-68

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

Anticancer agents that selectively kill tumor cells and spare normal tissues are urgently needed. Here, we engineered a cell-permeable peptidomimetic, shepherdin, modeled on the binding interface between the molecular chaperone Hsp90 and the antiapoptotic and mitotic regulator, survivin. Shepherdin makes extensive contacts with the ATP pocket of Hsp90, destabilizes its client proteins, and induces massive death of tumor cells by apoptotic and nonapoptotic mechanisms. Conversely, shepherdin does not reduce the viability of normal cells, and does not affect colony formation of purified hematopoietic progenitors. Systemic administration of shepherdin in vivo is well tolerated, and inhibits human tumor growth in mice without toxicity. Shepherdin could provide a potent and selective anticancer agent in humans.
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http://dx.doi.org/10.1016/j.ccr.2005.03.035DOI Listing
May 2005

Mitochondrial dynamics of survivin and "four dimensional" control of tumor cell apoptosis.

Cell Cycle 2005 Jan 12;4(1):21-3. Epub 2005 Jan 12.

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA.

The intense investigation of cell death pathways over the past few years has uncovered elevated complexity with panoply of molecular interactions, multiple intersecting gene networks and bidirectional crosstalk among disparate cellular regulators. What has remained more elusive is how these interactions are spatially arranged in the "four dimensions" of the cell as a whole, and their true relevance to human diseases. Fresh evidence obtained with survivin has unraveled a process of dynamic subcellular shuttling that is required to inhibit apoptosis during tumor growth, with the mitochondrion playing a central, orchestrating role.
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http://dx.doi.org/10.4161/cc.4.1.1367DOI Listing
January 2005

Mitochondrial survivin inhibits apoptosis and promotes tumorigenesis.

J Clin Invest 2004 Oct;114(8):1117-27

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

Evasion of apoptosis is a hallmark of cancer, but the molecular circuitries of this process are not understood. Here we show that survivin, a member of the inhibitor of apoptosis gene family that is overexpressed in cancer, exists in a novel mitochondrial pool in tumor cells. In response to cell death stimulation, mitochondrial survivin is rapidly discharged in the cytosol, where it prevents caspase activation and inhibits apoptosis. Selective targeting of survivin to mitochondria enhances colony formation in soft agar, accelerates tumor growth in immunocompromised animals, and abolishes tumor cell apoptosis in vivo. Therefore, mitochondrial survivin orchestrates a novel pathway of apoptosis inhibition, which contributes to tumor progression.
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http://dx.doi.org/10.1172/JCI22222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC522254PMC
October 2004

An IAP-IAP complex inhibits apoptosis.

J Biol Chem 2004 Aug 24;279(33):34087-90. Epub 2004 Jun 24.

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.

Regulators of apoptosis are thought to work in concert, but the molecular interactions of this process are not understood. Here, we show that in response to cell death stimulation, survivin, a member of the inhibitor of apoptosis (IAP) gene family, associates with another IAP protein, XIAP, via conserved baculovirus IAP repeats. Formation of a survivin-XIAP complex promotes increased XIAP stability against ubiquitination/proteasomal destruction and synergistic inhibition of apoptosis, which is abolished in XIAP(-/-) cells. Therefore, orchestration of an IAP-IAP complex regulates apoptosis.
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http://dx.doi.org/10.1074/jbc.C400236200DOI Listing
August 2004

Transcriptional expression of survivin and its splice variants in brain tumors in humans.

J Neurosurg 2003 Oct;99(4):738-45

Department of Neurosurgery, Central Clinical Laboratory, Osaka Medical College, Takatsuki City, Osaka, Japan.

Object: Survivin, one of the apoptosis inhibitor proteins, has been detected in most cancers in humans. In addition, two splice variants (survivin-2B and survivin-deltaEx3) have been identified. The authors investigated the transcription levels of survivin messenger (m)RNA and its splice variants in nine tumor cell lines, including gliomas, and in 25 brain tumor samples, by performing quantitative reverse transcription-polymerase chain reaction. The correlation between transcript expression levels and pathological findings were also analyzed.

Methods: Transcription levels were measured using primer pairs specific for survivin and either of its splice variants and were normalized to the glyceraldehyde 6-phosphate dehydrogenase. Among the tumor cell lines tested, glioblastoma cell lines showed the highest levels of survivin expression. Among brain tumor samples studied, survivin was preferentially expressed in malignant brain tumors and gliomas. The relative expression level of survivin-deltaEx3/survivin was significantly higher in malignant than in benign brain tumor samples. Expression patterns were dominant for survivin-deltaEx3 in malignant brain tumors and dominant for survivin-2B in benign ones. A significant linear correlation between survivin mRNA expression and MIB-1 labeling index was demonstrated in all brain tumor samples.

Conclusions: The authors' results indicate that quantifying the levels of survivin and its splice variants is useful for the prediction of the cell biological malignancy of gliomas, independent of their pathological features.
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http://dx.doi.org/10.3171/jns.2003.99.4.0738DOI Listing
October 2003

Therapeutic targeting of the survivin pathway in cancer: initiation of mitochondrial apoptosis and suppression of tumor-associated angiogenesis.

Clin Cancer Res 2003 Jul;9(7):2683-92

Department of Cancer Biology and the Cancer Center, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.

Purpose: Molecular antagonists of the inhibitor of apoptosis protein survivin have shown promise as novel anticancer strategies for triggering tumor cell apoptosis, dysregulating mitotic progression, and inhibiting tumor growth in preclinical models. However, how survivin couples to the cell death machinery has remained elusive, and the relevant cellular targets of survivin antagonists have not been completely elucidated.

Experimental Design: Human umbilical vein and dermal microvascular endothelial cells were infected with replication-deficient adenoviruses encoding survivin (pAd-Survivin), green fluorescent protein (pAd-GFP), or a phosphorylation-defective survivin Thr(34)-->Ala (pAd-T34A) dominant negative mutant. The effect of wild-type or mutant survivin was investigated on capillary network stability, endothelial cell viability, and caspase activation in vitro and on kinetics of tumor growth and development of angiogenesis in a breast cancer xenograft model in vivo. The cell death pathway initiated by survivin targeting was mapped with respect to cytochrome c release, changes in mitochondrial transmembrane potential, and apoptosome requirements using mouse embryonic fibroblasts deficient in Apaf-1 or caspase-9.

Results: Adenoviral transduction of endothelial cells with pAd-Survivin inhibited growth factor deprivation- or ceramide-induced apoptosis, reduced caspase-3 and -7 generation, and stabilized three-dimensional capillary networks in vitro. Conversely, expression of pAd-T34A caused apoptosis in umbilical vein and dermal microvascular endothelial cells and resulted in caspase-3 activity. Cell death induced by survivin targeting exhibited the hallmarks of mitochondrial-dependent apoptosis with release of cytochrome c and loss of mitochondrial transmembrane potential and was suppressed in Apaf-1 or caspase-9 knockout mouse embryonic fibroblasts. When injected in human breast cancer xenografts, pAd-T34A inhibited growth of established tumors and triggered tumor cell apoptosis in vivo. This was associated with a approximately 60% reduction in tumor-derived blood vessels by quantitative morphometry of CD31-stained tumor areas, and appearance of endothelial cell apoptosis by internucleosomal DNA fragmentation in vivo.

Conclusions: Survivin functions as a novel upstream regulator of mitochondrial-dependent apoptosis, and molecular targeting of this pathway results in anticancer activity via a dual mechanism of induction of tumor cell apoptosis and suppression of angiogenesis.
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July 2003

Relationship between types of common channel and development of biliary tract cancer in pancreaticobiliary maljunction.

Hepatogastroenterology 2002 Mar-Apr;49(44):322-5

Department of General and Gastroenterological Surgery, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan.

Background/aims: The incidence of biliary tract cancer development is high among patients with pancreaticobiliary maljunction. However, there have been no reports published evaluating the incidence of development of biliary tract cancers in pancreaticobiliary maljunction based on the morphology of the common channel at the junction of the bile and pancreatic ducts. We evaluated between types of common channel and development of biliary tract cancers in pancreaticobiliary maljunction.

Methodology: During the last 21 years, we have experienced 78 patients with pancreaticobiliary maljunction. Of those patients, 44 adult patients, whose morphologic types of common channel were identified by cholangiography, were enrolled in this study. The dilatation patterns of the common channel were classified into 3 types: A type (moderately dilated type), B type (markedly dilated type), and C type (non-dilated type). Evaluated items included the length and dilation patterns of the common channel, incidence of development of biliary tract cancers and proliferative activity in the biliary tract epithelium.

Results: Seventeen patients had a common channel shorter than 20 mm, while 27 had a common channel of 20 mm or longer. Eleven patients with a common channel of 20 mm or longer had development of bile tract cancers. The dilation patterns of the common channel were classified as A (11 patients), B (16 patients) and C type (17 patients). Amylase levels in the biliary tract were higher in patients with A and B type than in patients with the C type. Development of gallbladder cancer was observed in 6 patients with A, 2 patients with B and one patient with C, while development of bile duct cancer was observed in 2 patients with C and one patient with B. The PCNAL.I. of the biliary epithelium was higher in patients with A, B and C type in descending order.

Conclusions: The incidence of development of biliary tract cancer was higher in patients with common channel of 20 mm or longer. The proliferative activity in the biliary epithelium was accelerated in patients with A type, together with a high incidence of development of gallbladder cancer.
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December 2002

Studies on biliary tract carcinoma in the case with pancreaticobiliary maljunction.

Hepatogastroenterology 2002 Jan-Feb;49(43):104-8

Department of General and Gastroenterological Surgery, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka 569-8686, Japan.

Background/aims: The purpose of this study was to clarify the clinicopathological features of pancreaticobiliary maljunction and to determine the appropriate surgical approach for biliary tract with pancreaticobiliary maljunction.

Methodology: The data of 77 patients with pancreaticobiliary maljunction including 13, who had been treated for biliary tract cancer, were reviewed retrospectively. We assessed the clinical features, biological characteristics of the cancer, methods of surgical treatment, postoperative outcome and cell proliferating activity of the biliary epithelium, evaluated by the PCNALI (proliferating cell nuclear antigen-labeling index).

Results: The incidence of cancer development in the case with pancreaticobiliary maljunction was 13.4% in the bile duct dilatation group (n = 67) and 40.0% in the non-dilatation group (n = 10). Dissection of lymphadenectomy was performed in 10 (76.9%) of 13 patients, and curative resection was feasible in 9 of the 10 patients. Two (20.0%) of the 10 patients had lymph node involvement noted at surgery and died of recurrence. In the other eight patients without lymph node involvement at surgery, six patients underwent curative resection and are alive at 7 months to 11 years and 6 months after surgery. PCNALI of the biliary epithelium of the patients with pancreaticobiliary maljunction was significantly higher than that of the control group.

Conclusions: For patients with pancreaticobiliary maljunction, it should be stressed that the extrahepatic bile duct be prophylactically removed, even when there are no neoplasmatic changes because of high prevalence of cancer development, presumably predicted by the increase of cell proliferative activity in the biliary epithelium. For patients with biliary cancer, early detection at the stage with no lymph node involvement is essential to secure for long-term survival.
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October 2002