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Ingersoll MA, Lutze RD, Kelmann RG, Kresock DF, Marsh JD, Quevedo RV, Zuo J, Teitz T. KSR1 knockout mouse model demonstrates MAPK pathway's key role in cisplatin- and noise-induced hearing loss. J Neurosci 2024:e2174232024. [PMID: 38548338 DOI: 10.1523/jneurosci.2174-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 03/09/2024] [Accepted: 03/21/2024] [Indexed: 04/09/2024] Open
Abstract
Hearing loss is a major disability in everyday life and therapeutic interventions to protect hearing would benefit a large portion of the world population. Here we found that mice devoid of the protein kinase suppressor of RAS 1 (KSR1) in their tissues (germline KO mice) exhibit resistance to both cisplatin- and noise-induced permanent hearing loss compared to their wild-type KSR1 littermates. KSR1 is a scaffold protein that brings in proximity the mitogen-activated protein kinase (MAPK) proteins BRAF, MEK1/2 and ERK1/2 and assists in their activation through a phosphorylation cascade induced by both cisplatin and noise insults in the cochlear cells. KSR1, BRAF, MEK1/2, and ERK1/2 are all ubiquitously expressed in the cochlea. Deleting the KSR1 protein tempered down the MAPK phosphorylation cascade in the cochlear cells following both cisplatin and noise insults and conferred hearing protection of up to 30 dB SPL in three tested frequencies in male and female mice. Treatment with dabrafenib, an FDA-approved oral BRAF inhibitor, protected male and female KSR1 wild-type mice from both cisplatin- and noise-induced hearing loss. Dabrafenib treatment did not enhance the protection of KO KSR1 mice, providing evidence dabrafenib works primarily through the MAPK pathway. Thus, either elimination of the KSR1 gene expression or drug inhibition of the MAPK cellular pathway in mice resulted in profound protection from both cisplatin- and noise-induce hearing loss. Inhibition of the MAPK pathway, a cellular pathway that responds to damage in the cochlear cells, can prove a valuable strategy to protect and treat hearing loss.Significance Statement Ten percent of the world population suffers from hearing loss but this impairment may be preventable. We show that mice devoid of the KSR1 protein (KO) exhibit resistance to cisplatin- and noise-induced permanent hearing loss compared to wild-type littermates that harbor the protein. Removing KSR1 tempers down the MAPK phosphorylation cascade of BRAF-MEK-ERK induced in the cochlea following cisplatin and noise insults. Treatment of KSR1 wild-type mice following cisplatin or noise with an FDA-approved BRAF inhibitor, dabrafenib, protected the hearing and, importantly, did not confer additional protection to the KO KSR1 mice. Hence, the MAPK pathway has a unique role in responding to cochlear damage and removing KSR1 gene expression or drug inhibition of the pathway results in hearing protection.
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Affiliation(s)
- Matthew A Ingersoll
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Richard D Lutze
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Regina G Kelmann
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Daniel F Kresock
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Jordan D Marsh
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Rene V Quevedo
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Jian Zuo
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Tal Teitz
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
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Pushpan CK, Kresock DF, Ingersoll MA, Lutze RD, Keirns DL, Hunter WJ, Bashir K, Teitz T. Repurposing AZD5438 and Dabrafenib for Cisplatin-Induced AKI. J Am Soc Nephrol 2024; 35:22-40. [PMID: 37962623 PMCID: PMC10786615 DOI: 10.1681/asn.0000000000000261] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/09/2023] [Indexed: 11/15/2023] Open
Abstract
SIGNIFICANCE STATEMENT To combat both untoward effects of nephrotoxicity and ototoxicity in cisplatin-treated patients, two potential therapeutic oral anticancer drugs AZD5438 and dabrafenib, a phase-2 clinical trial protein kinase CDK2 inhibitor and an US Food and Drug Administration-approved drug BRAF inhibitor, respectively, were tested in an established mouse AKI model. Both drugs have previously been shown to protect significantly against cisplatin-induced hearing loss in mice. Each drug ameliorated cisplatin-induced increases in the serum biomarkers BUN, creatinine, and neutrophil gelatinase-associated lipocalin. Drugs also improved renal histopathology and inflammation, mitigated cell death by pyroptosis and necroptosis, and significantly enhanced overall survival of cisplatin-treated mice. BACKGROUND Cisplatin is an effective chemotherapy agent for a wide variety of solid tumors, but its use is dose-limited by serious side effects, including AKI and hearing loss. There are no US Food and Drug Administration-approved drugs to treat both side effects. Recently, two anticancer oral drugs, AZD5438 and dabrafenib, were identified as protective against cisplatin-induced hearing loss in mice. We hypothesize that similar cell stress and death pathways are activated in kidney and inner ear cells when exposed to cisplatin and tested whether these drugs alleviate cisplatin-induced AKI. METHODS The HK-2 cell line and adult FVB mice were used to measure the protection from cisplatin-induced cell death and AKI by these drugs. Serum markers of kidney injury, BUN, creatinine, and neutrophil gelatinase-associated lipocalin as well as histology of kidneys were analyzed. The levels of markers of kidney cell death, including necroptosis and pyroptosis, pERK, and proliferating cell nuclear antigen, were also examined by Western blotting and immunofluorescence. In addition, CDK2 knockout (KO) mice were used to confirm AZD5438 protective effect is through CDK2 inhibition. RESULTS The drugs reduced cisplatin-induced cell death in the HK-2 cell line and attenuated cisplatin-induced AKI in mice. The drugs reduced serum kidney injury markers, inhibited cell death, and reduced the levels of pERK and proliferating cell nuclear antigen, all of which correlated with prolonged animal survival. CDK2 KO mice were resistant to cisplatin-induced AKI, and AZD5438 conferred no additional protection in the KO mice. CONCLUSIONS Cisplatin-induced damage to the inner ear and kidneys shares similar cellular beneficial responses to AZD5438 and dabrafenib, highlighting the potential therapeutic use of these agents to treat both cisplatin-mediated kidney damage and hearing loss.
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Affiliation(s)
- Chithra K. Pushpan
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
| | - Daniel F. Kresock
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
| | - Matthew A. Ingersoll
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
| | - Richard D. Lutze
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
| | - Darby L. Keirns
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
| | - William J. Hunter
- Department of Pathology, Creighton University School of Medicine, Omaha, Nebraska
| | - Khalid Bashir
- Renal Division, Department of Medicine, CHI Nephrology and Creighton University Medical Center, Omaha, Nebraska
| | - Tal Teitz
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, Nebraska
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Ingersoll MA, Lutze RD, Pushpan CK, Kelmann RG, Liu H, May MT, Hunter WJ, He DZ, Teitz T. Dabrafenib protects from cisplatin-induced hearing loss in a clinically relevant mouse model. JCI Insight 2023; 8:e171140. [PMID: 37934596 PMCID: PMC10807719 DOI: 10.1172/jci.insight.171140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 11/02/2023] [Indexed: 11/09/2023] Open
Abstract
The widely used chemotherapy cisplatin causes permanent hearing loss in 40%-60% of patients with cancer. One drug, sodium thiosulfate, is approved by the FDA for use in pediatric patients with localized solid tumors for preventing cisplatin-induced hearing loss, but more drugs are desperately needed. Here, we tested dabrafenib, an FDA-approved BRAF kinase inhibitor and anticancer drug, in a clinically relevant multidose cisplatin mouse model. The protective effects of dabrafenib, given orally twice daily with cisplatin, were determined by functional hearing tests and cochlear outer hair cell counts. Toxicity of the drug cotreatment was evaluated, and levels of phosphorylated ERK were measured. A dabrafenib dose of 3 mg/kg BW, twice daily, in mice, was determined to be the minimum effective dose, and it is equivalent to one-tenth of the daily FDA-approved dose for human cancer treatment. The levels of hearing protection acquired, 20-25 dB at the 3 frequencies tested, in both female and male mice, persisted for 4 months after completion of treatments. Moreover, dabrafenib exhibited a good in vivo therapeutic index (> 25), protected hearing in 2 mouse strains, and diminished cisplatin-induced weight loss. This study demonstrates that dabrafenib is a promising candidate drug for protection from cisplatin-induced hearing loss.
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Affiliation(s)
| | | | | | | | | | | | - William J. Hunter
- Department of Pathology, School of Medicine, Creighton University, Omaha, Nebraska, USA
| | | | - Tal Teitz
- Department of Pharmacology and Neuroscience
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Ingersoll MA, Lutze RD, Kelmann RG, Kresock DF, Marsh JD, Quevedo RV, Zuo J, Teitz T. KSR1 knockout mouse model demonstrates MAPK pathway's key role in cisplatin- and noise-induced hearing loss. bioRxiv 2023:2023.11.08.566316. [PMID: 38014104 PMCID: PMC10680565 DOI: 10.1101/2023.11.08.566316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Hearing loss is a major disability in everyday life and therapeutic interventions to protect hearing would benefit a large portion of the world population. Here we found that mice devoid of the protein kinase suppressor of RAS 1 (KSR1) in their tissues (germline KO mice) exhibit resistance to both cisplatin- and noise-induced permanent hearing loss compared to their wild-type KSR1 littermates. KSR1 is expressed in the cochlea and is a scaffold protein that brings in proximity the mitogen-activated protein kinase (MAPK) proteins BRAF, MEK and ERK and assists in their activation through a phosphorylation cascade induced by both cisplatin and noise insults in the cochlear cells. Deleting the KSR1 protein tempered down the MAPK phosphorylation cascade in the cochlear cells following both cisplatin and noise insults and conferred hearing protection of up to 30 dB SPL in three tested frequencies in mice. Treatment with dabrafenib, an FDA-approved oral BRAF inhibitor, downregulated the MAPK kinase cascade and protected the KSR1 wild-type mice from both cisplatin- and noise-induced hearing loss. Dabrafenib treatment did not enhance the protection of KO KSR1 mice, as excepted, providing evidence dabrafenib works primarily through the MAPK pathway. Thus, either elimination of the KSR1 gene expression or drug inhibition of the MAPK cellular pathway in mice resulted in profound protection from both cisplatin- and noise-induce hearing loss. Inhibition of the MAPK pathway, a cellular pathway that responds to damage in the cochlear cells, can prove a valuable strategy to protect and treat hearing loss.
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Affiliation(s)
- Matthew A. Ingersoll
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Richard D. Lutze
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Regina G. Kelmann
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Daniel F. Kresock
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Jordan D. Marsh
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Rene V. Quevedo
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Jian Zuo
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Tal Teitz
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
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5
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Lutze RD, Ingersoll MA, Thotam A, Joseph A, Fernandes J, Teitz T. ERK1/2 Inhibition Alleviates Noise-Induced Hearing Loss While Tempering Down the Immune Response. bioRxiv 2023:2023.10.18.563007. [PMID: 37905140 PMCID: PMC10614960 DOI: 10.1101/2023.10.18.563007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Noise-induced hearing loss (NIHL) is a major cause of hearing impairment, yet no FDA-approved drugs exist to prevent it. Targeting the mitogen activated protein kinase (MAPK) cellular pathway has emerged as a promising approach to attenuate NIHL. Tizaterkib is an orally bioavailable, highly specific ERK1/2 inhibitor, currently in Phase-1 anticancer clinical trials. Here, we tested tizaterkib's efficacy against permanent NIHL in mice at doses equivalent to what humans are currently prescribed in clinical trials. The drug given orally 24 hours after noise exposure, protected an average of 20-25 dB SPL in three frequencies, in female and male mice, had a therapeutic window >50, and did not confer additional protection to KSR1 genetic knockout mice, showing the drug works through the MAPK pathway. Tizaterkib shielded from noise-induced cochlear synaptopathy, and a 3-day, twice daily, treatment with the drug was the optimal determined regimen. Importantly, tizaterkib was shown to decrease the number of CD45 and CD68 positive immune cells in the cochlea following noise exposure, which could be part of the protective mechanism of MAPK inhibition.
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Affiliation(s)
- Richard D. Lutze
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Matthew A. Ingersoll
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Alena Thotam
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Anjali Joseph
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Joshua Fernandes
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Tal Teitz
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
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Ingersoll MA, Malloy EA, Caster LE, Holland EM, Xu Z, Zallocchi M, Currier D, Liu H, He DZZ, Min J, Chen T, Zuo J, Teitz T. BRAF inhibition protects against hearing loss in mice. Sci Adv 2020; 6:6/49/eabd0561. [PMID: 33268358 PMCID: PMC7821884 DOI: 10.1126/sciadv.abd0561] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/20/2020] [Indexed: 05/13/2023]
Abstract
Hearing loss caused by noise, aging, antibiotics, and chemotherapy affects 10% of the world population, yet there are no Food and Drug Administration (FDA)-approved drugs to prevent it. Here, we screened 162 small-molecule kinase-specific inhibitors for reduction of cisplatin toxicity in an inner ear cell line and identified dabrafenib (TAFINLAR), a BRAF kinase inhibitor FDA-approved for cancer treatment. Dabrafenib and six additional kinase inhibitors in the BRAF/MEK/ERK cellular pathway mitigated cisplatin-induced hair cell death in the cell line and mouse cochlear explants. In adult mice, oral delivery of dabrafenib repressed ERK phosphorylation in cochlear cells, and protected from cisplatin- and noise-induced hearing loss. Full protection was achieved in mice with co-treatment with oral AZD5438, a CDK2 kinase inhibitor. Our study explores a previously unidentified cellular pathway and molecular target BRAF kinase for otoprotection and may advance dabrafenib into clinics to benefit patients with cisplatin- and noise-induced ototoxicity.
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Affiliation(s)
- Matthew A Ingersoll
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Emma A Malloy
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Lauryn E Caster
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Eva M Holland
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Zhenhang Xu
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Marisa Zallocchi
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Duane Currier
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Huizhan Liu
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - David Z Z He
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Jaeki Min
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jian Zuo
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE 68178, USA
| | - Tal Teitz
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE 68178, USA.
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7
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Hazlitt RA, Teitz T, Bonga JD, Fang J, Diao S, Iconaru L, Yang L, Goktug AN, Currier DG, Chen T, Rankovic Z, Min J, Zuo J. Development of Second-Generation CDK2 Inhibitors for the Prevention of Cisplatin-Induced Hearing Loss. J Med Chem 2018; 61:7700-7709. [PMID: 30091915 DOI: 10.1021/acs.jmedchem.8b00669] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There are currently no FDA-approved therapies to prevent the hearing loss associated with the usage of cisplatin in chemotherapeutic regimens. We recently demonstrated that the pharmacologic inhibition with kenpaullone or genetic deletion of CDK2 preserved hearing function in animal models treated with cisplatin, which suggests that CDK2 is a promising therapeutic target to prevent cisplatin-induced ototoxicity. In this study, we identified two lead compounds, AT7519 and AZD5438, from a focused library screen of 187 CDK2 inhibitors, performed in an immortalized cell line derived from neonatal mouse cochleae treated with cisplatin. Moreover, we screened 36 analogues of AT7519 and identified analogue 7, which exhibited an improved therapeutic index. When delivered locally, analogue 7 and AZD5438 both provided significant protection against cisplatin-induced ototoxicity in mice. Thus, we have identified two additional compounds that prevent cisplatin-induced ototoxicity in vivo and provided further evidence that CDK2 is a druggable target for treating cisplatin-induced ototoxicity.
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8
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Teitz T, Fang J, Goktug AN, Bonga JD, Diao S, Hazlitt RA, Iconaru L, Morfouace M, Currier D, Zhou Y, Umans RA, Taylor MR, Cheng C, Min J, Freeman B, Peng J, Roussel MF, Kriwacki R, Guy RK, Chen T, Zuo J. CDK2 inhibitors as candidate therapeutics for cisplatin- and noise-induced hearing loss. J Exp Med 2018. [PMID: 29514916 PMCID: PMC5881471 DOI: 10.1084/jem.20172246] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hearing loss caused by aging, noise, cisplatin toxicity, or other insults affects 360 million people worldwide, but there are no Food and Drug Administration-approved drugs to prevent or treat it. We screened 4,385 small molecules in a cochlear cell line and identified 10 compounds that protected against cisplatin toxicity in mouse cochlear explants. Among them, kenpaullone, an inhibitor of multiple kinases, including cyclin-dependent kinase 2 (CDK2), protected zebrafish lateral-line neuromasts from cisplatin toxicity and, when delivered locally, protected adult mice and rats against cisplatin- and noise-induced hearing loss. CDK2-deficient mice displayed enhanced resistance to cisplatin toxicity in cochlear explants and to cisplatin- and noise-induced hearing loss in vivo. Mechanistically, we showed that kenpaullone directly inhibits CDK2 kinase activity and reduces cisplatin-induced mitochondrial production of reactive oxygen species, thereby enhancing cell survival. Our experiments have revealed the proapoptotic function of CDK2 in postmitotic cochlear cells and have identified promising therapeutics for preventing hearing loss.
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Affiliation(s)
- Tal Teitz
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
| | - Jie Fang
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
| | - Asli N Goktug
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Justine D Bonga
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
| | - Shiyong Diao
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
| | - Robert A Hazlitt
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
| | - Luigi Iconaru
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN.,Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN
| | - Marie Morfouace
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN
| | - Duane Currier
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Yinmei Zhou
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN
| | - Robyn A Umans
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Michael R Taylor
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Cheng Cheng
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN
| | - Jaeki Min
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Burgess Freeman
- Preclinical PK Shared Resource, St. Jude Children's Research Hospital, Memphis, TN
| | - Junmin Peng
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN.,Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN
| | - Martine F Roussel
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN
| | - Richard Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN
| | - R Kiplin Guy
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN
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9
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Teitz T, Goktug AN, Chen T, Zuo J. Development of Cell-Based High-Throughput Chemical Screens for Protection Against Cisplatin-Induced Ototoxicity. Methods Mol Biol 2016; 1427:419-30. [PMID: 27259939 DOI: 10.1007/978-1-4939-3615-1_22] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Various compounds have been tested in recent years for protection against cisplatin-induced hearing loss, but no compound has yet been FDA approved for clinical use in patients. Towards this goal, we developed an unbiased, high-throughput, mammalian cochlear cell-based chemical screen that allowed quantification of the protection ability of bioactive compounds and ranked them for future testing ex vivo in cochlear explant cultures and in vivo in animal models. In our primary screens, protection in the HEI-OC1 organ of Corti immortalized cell line was measured by the ability of each compound to inhibit caspase-3/7 activity triggered by cisplatin treatment (50 μM cisplatin for 22 h). A total of 4385 unique bioactive compounds were tested in a single dose of 8 μM and promising compounds were validated by dose response curves covering ten, 1:3 serial diluted concentrations. Primary hits were defined as having more than 60 % inhibition of the caspase-3/7 activity. Toxicity of the top compounds was measured by a CellTiter-Glo (CTG) assay that measured the viability of the cells in the presence of compound alone in similar dose responsive analysis. A combination of the caspase-3/7 inhibition activity assay (as measured by IC50) and the CTG viability assay (as determined by LD50) identified the top protective compounds in the HEI-OC1 cells. In the future, the top hits in our screens will be tested for their protective ability ex vivo in mouse cochlear explants and in vivo in animal models. Our mammalian cochlear cell-based, high-throughput chemical screening assays described here can be further modified and represent an initial successful step towards therapeutic intervention of hearing disorders, an unmet medical need of our society.
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Affiliation(s)
- Tal Teitz
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Asli N Goktug
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA.
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Xu H, Robinson GW, Huang J, Lim JYS, Zhang H, Bass JK, Broniscer A, Chintagumpala M, Bartels U, Gururangan S, Hassall T, Fisher M, Cohn R, Yamashita T, Teitz T, Zuo J, Onar-Thomas A, Gajjar A, Stewart CF, Yang JJ. Common variants in ACYP2 influence susceptibility to cisplatin-induced hearing loss. Nat Genet 2015; 47:263-6. [PMID: 25665007 PMCID: PMC4358157 DOI: 10.1038/ng.3217] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 01/14/2015] [Indexed: 02/05/2023]
Abstract
Taking a genome-wide association study approach, we identified inherited genetic variations in ACYP2 associated with cisplatin-related ototoxicity (rs1872328: P = 3.9 × 10(-8), hazard ratio = 4.5) in 238 children with newly diagnosed brain tumors, with independent replication in 68 similarly treated children. The ACYP2 risk variant strongly predisposed these patients to precipitous hearing loss and was related to ototoxicity severity. These results point to new biology underlying the ototoxic effects of platinum agents.
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Affiliation(s)
- Heng Xu
- 1] Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. [2] Department of Laboratory Medicine, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China
| | - Giles W Robinson
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jie Huang
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Joshua Yew-Suang Lim
- 1] Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. [2] Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Hui Zhang
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Johnnie K Bass
- Rehabilitation Services, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Alberto Broniscer
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | | | - Ute Bartels
- Department of Haematology and Oncology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sri Gururangan
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Tim Hassall
- Department of Oncology, The Royal Children's Hospital, Parkville, Victoria, Australia
| | - Michael Fisher
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Richard Cohn
- School of Women's and Children's Health, University of New South Wales, Kensington, New South Wales, Australia
| | - Tetsuji Yamashita
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Tal Teitz
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jian Zuo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Arzu Onar-Thomas
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Amar Gajjar
- Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Clinton F Stewart
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jun J Yang
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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11
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Teitz T, Inoue M, Valentine MB, Zhu K, Rehg JE, Zhao W, Finkelstein D, Wang YD, Johnson MD, Calabrese C, Rubinstein M, Hakem R, Weiss WA, Lahti JM. Th-MYCN mice with caspase-8 deficiency develop advanced neuroblastoma with bone marrow metastasis. Cancer Res 2013; 73:4086-97. [PMID: 23536557 DOI: 10.1158/0008-5472.can-12-2681] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neuroblastoma, the most common extracranial pediatric solid tumor, is responsible for 15% of all childhood cancer deaths. Patients frequently present at diagnosis with metastatic disease, particularly to the bone marrow. Advances in therapy and understanding of the metastatic process have been limited due, in part, to the lack of animal models harboring bone marrow disease. The widely used transgenic model, the Th-MYCN mouse, exhibits limited metastasis to this site. Here, we establish the first genetic immunocompetent mouse model for metastatic neuroblastoma with enhanced secondary tumors in the bone marrow. This model recapitulates 2 frequent alterations in metastatic neuroblastoma, overexpression of MYCN and loss of caspase-8 expression. Mouse caspase-8 gene was deleted in neural crest lineage cells by crossing a Th-Cre transgenic mouse with a caspase-8 conditional knockout mouse. This mouse was then crossed with the neuroblastoma prone Th-MYCN mouse. Although overexpression of MYCN by itself rarely caused bone marrow metastasis, combining MYCN overexpression and caspase-8 deletion significantly enhanced bone marrow metastasis (37% incidence). Microarray expression studies of the primary tumors mRNAs and microRNAs revealed extracellular matrix structural changes, increased expression of genes involved in epithelial to mesenchymal transition, inflammation, and downregulation of miR-7a and miR-29b. These molecular changes have been shown to be associated with tumor progression and activation of the cytokine TGF-β pathway in various tumor models. Cytokine TGF-β can preferentially promote single cell motility and blood-borne metastasis and therefore activation of this pathway may explain the enhanced bone marrow metastasis observed in this animal model.
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Affiliation(s)
- Tal Teitz
- Departments of Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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12
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Teitz T, Stanke JJ, Federico S, Bradley CL, Brennan R, Zhang J, Johnson MD, Sedlacik J, Inoue M, Zhang ZM, Frase S, Rehg JE, Hillenbrand CM, Finkelstein D, Calabrese C, Dyer MA, Lahti JM. Preclinical models for neuroblastoma: establishing a baseline for treatment. PLoS One 2011; 6:e19133. [PMID: 21559450 PMCID: PMC3084749 DOI: 10.1371/journal.pone.0019133] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 03/16/2011] [Indexed: 11/18/2022] Open
Abstract
Background Preclinical models of pediatric cancers are essential for testing new
chemotherapeutic combinations for clinical trials. The most widely used
genetic model for preclinical testing of neuroblastoma is the TH-MYCN mouse.
This neuroblastoma-prone mouse recapitulates many of the features of human
neuroblastoma. Limitations of this model include the low frequency of bone
marrow metastasis, the lack of information on whether the gene expression
patterns in this system parallels human neuroblastomas, the relatively slow
rate of tumor formation and variability in tumor penetrance on different
genetic backgrounds. As an alternative, preclinical studies are frequently
performed using human cell lines xenografted into immunocompromised mice,
either as flank implant or orthtotopically. Drawbacks of this system include
the use of cell lines that have been in culture for years, the inappropriate
microenvironment of the flank or difficult, time consuming surgery for
orthotopic transplants and the absence of an intact immune system. Principal Findings Here we characterize and optimize both systems to increase their utility for
preclinical studies. We show that TH-MYCN mice develop tumors in the
paraspinal ganglia, but not in the adrenal, with cellular and gene
expression patterns similar to human NB. In addition, we present a new
ultrasound guided, minimally invasive orthotopic xenograft method. This
injection technique is rapid, provides accurate targeting of the injected
cells and leads to efficient engraftment. We also demonstrate that tumors
can be detected, monitored and quantified prior to visualization using
ultrasound, MRI and bioluminescence. Finally we develop and test a
“standard of care” chemotherapy regimen. This protocol, which is
based on current treatments for neuroblastoma, provides a baseline for
comparison of new therapeutic agents. Significance The studies suggest that use of both the TH-NMYC model of neuroblastoma and
the orthotopic xenograft model provide the optimal combination for testing
new chemotherapies for this devastating childhood cancer.
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Affiliation(s)
- Tal Teitz
- Department of Tumor Cell Biology, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
| | - Jennifer J. Stanke
- Department of Tumor Cell Biology, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
| | - Sara Federico
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
- Department of Hematology/Oncology, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
| | - Cori L. Bradley
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
| | - Rachel Brennan
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
| | - Jiakun Zhang
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
| | - Melissa D. Johnson
- Animal Imaging Center, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Jan Sedlacik
- Department of Radiological Sciences, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
| | - Madoka Inoue
- Department of Tumor Cell Biology, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
| | - Ziwei M. Zhang
- Animal Imaging Center, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Sharon Frase
- Cell and Tissue Imaging, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Claudia M. Hillenbrand
- Department of Radiological Sciences, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
| | - David Finkelstein
- Information Sciences, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Christopher Calabrese
- Animal Imaging Center, St. Jude Children's Research Hospital,
Memphis, Tennessee, United States of America
| | - Michael A. Dyer
- Department of Developmental Neurobiology, St. Jude Children's
Research Hospital, Memphis, Tennessee, United States of America
- Department of Ophthalmology, University of Tennessee Health Science
Center, Memphis, Tennessee, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of
America
- * E-mail: (JML); (MAD)
| | - Jill M. Lahti
- Department of Tumor Cell Biology, St. Jude Children's Research
Hospital, Memphis, Tennessee, United States of America
- Department of Molecular Sciences, University of Tennessee Health Science
Center, Memphis, Tennessee, United States of America
- * E-mail: (JML); (MAD)
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13
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Barbero S, Mielgo A, Torres V, Teitz T, Shields DJ, Mikolon D, Bogyo M, Barilà D, Lahti JM, Schlaepfer D, Stupack DG. Caspase-8 association with the focal adhesion complex promotes tumor cell migration and metastasis. Cancer Res 2009; 69:3755-63. [PMID: 19383910 DOI: 10.1158/0008-5472.can-08-3937] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Caspase-8 is a proapoptotic protease that suppresses neuroblastoma metastasis by inducing programmed cell death. Paradoxically, caspase-8 can also promote cell migration among nonapoptotic cells; here, we show that caspase-8 can promote metastasis when apoptosis is compromised. Migration is enhanced by caspase-8 recruitment to the cellular migration machinery following integrin ligation. Caspase-8 catalytic activity is not required for caspase-8-enhanced cell migration; rather, caspase-8 interacts with a multiprotein complex that can include focal adhesion kinase and calpain 2 (CPN2), enhancing cleavage of focal adhesion substrates and cell migration. Caspase-8 association with CPN2/calpastatin disrupts calpastatin-mediated inhibition of CPN2. In vivo, knockdown of either caspase-8 or CPN2 disrupts metastasis among apoptosis-resistant tumors. This unexpected molecular collaboration provides an explanation for the continued or elevated expression of caspase-8 observed in many tumors.
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Affiliation(s)
- Simone Barbero
- Department of Pathology, Moores UCSD Cancer Center, University of California-San Diego, San Diego, California 92093, USA
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14
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Abstract
To develop metastatic capability, tumor cells must evolve the capacity to survive in novel microenvironments. Recently, we showed that metastasis of neuroblastoma cells is enhanced by loss of caspase-8, an event that occurs frequently in this malignancy. In poorly metastatic cells, unligated integrins were found to trigger activation of caspase-8, providing a selective pressure to promote its attenuation and thereby increased survival in foreign adhesive environments. Our findings suggest one mechanism by which the organotropism of metastatic cancer cells can arise.
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Affiliation(s)
- Jill M Lahti
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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15
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Abstract
Neuroblastoma, a common tumor of nervous system origin in young children, is usually detected only after the primary tumor has metastasized and the chances of its complete removal are low. Metastatic neuroblastoma cells commonly suppress expression of the gene encoding caspase-8. In a neuroblastoma murine model, expression of caspase-8 and integrin alpha3beta1 was dramatically reduced during tumor development. Analysis of clinical biopsies supported the observation that expression of both genes is low in human patients with metastatic disease. These data suggest that loss of expression of both caspase-8 and unligated integrins contribute to the survival of tumor cells migrating from the primary tumor. Integrin receptors that are unable to find appropriate ligands can form a large molecular complex containing caspase-8, explaining why cells that have diminished expression of either of these two genes have a significant survival advantage in foreign microenvironments. Thus, upregulating expression of caspase-8 and integrins, or alternatively, antagonizing integrins within the primary tumor may be important therapeutically in halting neuroblastoma metastasis.
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Affiliation(s)
- Tal Teitz
- Department of Genetics and Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
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16
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Stupack DG, Teitz T, Potter MD, Mikolon D, Houghton PJ, Kidd VJ, Lahti JM, Cheresh DA. Potentiation of neuroblastoma metastasis by loss of caspase-8. Nature 2006; 439:95-9. [PMID: 16397500 DOI: 10.1038/nature04323] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Accepted: 10/07/2005] [Indexed: 11/08/2022]
Abstract
Neuroblastoma, the most common paediatric solid tumour, arises from defective neural crest cells. Genetic alterations occur frequently in the most aggressive neuroblastomas. In particular, deletion or suppression of the proapoptotic enzyme caspase-8 is common in malignant, disseminated disease, although the effect of this loss on disease progression is unclear. Here we show that suppression of caspase-8 expression occurs during the establishment of neuroblastoma metastases in vivo, and that reconstitution of caspase-8 expression in deficient neuroblastoma cells suppressed their metastases. Caspase-8 status was not a predictor of primary tumour growth; rather, caspase-8 selectively potentiated apoptosis in neuroblastoma cells invading the collagenous stroma at the tumour margin. Apoptosis was initiated by unligated integrins by means of a process known as integrin-mediated death. Loss of caspase-8 or integrin rendered these cells refractory to integrin-mediated death, allowed cellular survival in the stromal microenvironment, and promoted metastases. These findings define caspase-8 as a metastasis suppressor gene that, together with integrins, regulates the survival and invasive capacity of neuroblastoma cells.
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Affiliation(s)
- Dwayne G Stupack
- Department of Pathology and The John and Rebecca Moores Cancer Center, The University of California at San Diego, La Jolla, California 92093-0803, USA.
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17
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Teitz T, Wei T, Liu D, Valentine V, Valentine M, Grenet J, Lahti JM, Kidd VJ. Caspase-9 and Apaf-1 are expressed and functionally active in human neuroblastoma tumor cell lines with 1p36 LOH and amplified MYCN. Oncogene 2002; 21:1848-58. [PMID: 11896617 DOI: 10.1038/sj.onc.1205180] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2001] [Revised: 11/08/2001] [Accepted: 11/13/2001] [Indexed: 11/09/2022]
Abstract
Important roles have been suggested for caspase-8, caspase-9 and Apaf-1 in controlling tumor development and their sensitivity to chemotherapeutic agents. Methylation and deletion of Apaf-1 and CASP8 results in the loss of their expression in melanoma and neuroblastoma, respectively, while CASP9 localization to 1p36.1 suggests it is a good candidate tumor suppressor. The status of CASP9 and Apaf-1 expression in numerous neuroblastoma cell lines with/without amplified MYCN and chromosome 1p36 loss-of-heterozygosity (LOH) was therefore examined to test the hypothesis that one or both of these genes are tumor suppressors in neuroblastoma. Although CASP9 is included in the region encompassing 1p36 LOH in all neuroblastoma cell lines examined, the remaining CASP9 allele(s) express a functional caspase-9 enzyme. Apaf-1 is also expressed in all neuroblastoma tumor cell lines examined. Thus, the CASP9 or Apaf-1 genes do not appear to function as tumor suppressors in MYCN amplified neuroblastomas. However, approximately 20% of the neuroblastoma cell lines with methylated CASP8 alleles are also highly resistant to staurosporine (STS)- and radiation-induced cell death, presumably because cytochrome c is not released from mitochondria. This suggests that a second, smaller sub-group of MYCN amplified neuroblastoma tumors exists with defect(s) in apoptotic signaling components upstream of caspase-9 and Apaf-1. Since no consistent differences in Bcl-2, Bcl-x(L) or Bax expression were seen in the STS- and radiation-resistant neuroblastomas, it suggests that a unique mitochondrial signaling factor(s) is responsible for the defect in cytochrome c release in this sub-group of tumors.
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MESH Headings
- Apoptosis/genetics
- Apoptotic Protease-Activating Factor 1
- Caspase 9
- Caspases/genetics
- Caspases/metabolism
- Chromosome Deletion
- Chromosomes, Human, Pair 1/genetics
- Cytochrome c Group/metabolism
- DNA Primers/chemistry
- Enzyme Inhibitors/pharmacology
- Gene Amplification
- Genes, myc/genetics
- Humans
- Immunoblotting
- In Situ Hybridization, Fluorescence
- Loss of Heterozygosity
- Microsatellite Repeats
- Neuroblastoma/genetics
- Neuroblastoma/metabolism
- Neuroblastoma/pathology
- Poly (ADP-Ribose) Polymerase-1
- Poly(ADP-ribose) Polymerases
- Proteins/genetics
- Proteins/metabolism
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Staurosporine/pharmacology
- Transcription, Genetic
- Transduction, Genetic
- Tumor Cells, Cultured/metabolism
- Tumor Cells, Cultured/pathology
- Tumor Cells, Cultured/radiation effects
- Tumor Suppressor Protein p53/metabolism
- bcl-X Protein
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Affiliation(s)
- Tal Teitz
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, TN 38105, USA
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18
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Teitz T, Lahti JM, Kidd VJ. Aggressive childhood neuroblastomas do not express caspase-8: an important component of programmed cell death. J Mol Med (Berl) 2001; 79:428-36. [PMID: 11511973 DOI: 10.1007/s001090100233] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2000] [Accepted: 04/17/2001] [Indexed: 01/13/2023]
Abstract
Neuroblastomas that overexpress N-Myc due to amplification of the MYCN oncogene are aggressive tumors that become very resistant to treatment by chemotherapy and irradiation. to identify tumor suppressor genes in this group of neuroblastomas we analyzed the expression and function of both apoptosis-related cell cycle regulatory genes in cell lines and patient tumor samples. We found that in a high percentage of neuroblastoma cell lines and patient samples with amplified MYCN, caspase-8 mRNA is not expressed. The caspase-8 gene, CASP8, was deleted or silenced by methylation in the neuroblastoma cell lines while methylation of its promoter region was the predominant mechanism for its inactivation in the patient tumor samples. Reintroduction of caspase-8 into the neuroblastoma cell lines resensitized these cells to drug-induced and survival factor dependent apoptosis. Subsequently others have also shown that caspase-8 is silenced by methylation in neuroblastoma and peripheral neural ectodermal tumors, and that the caspase-9 regulator Apaf-1 is silenced by methylation in melanoma cell lines and patient samples. We conclude that caspase-8 acts as a tumor suppressor gene in neuroblastomas, that its silencing provides a permissive environment for MYCN gene amplification once the tumors are treated with chemotherapeutic drugs/irradiation, and that expression of this gene in these tumor cells may be of clinical benefit. We also discuss the possible significance of the neural crest cell progenitor cell origin and the silencing of important apoptotic regulators via methylation in both neuroblastoma and melanoma tumors.
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Affiliation(s)
- T Teitz
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, TN 38105, USA.
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19
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Takita J, Yang HW, Chen YY, Hanada R, Yamamoto K, Teitz T, Kidd V, Hayashi Y. Allelic imbalance on chromosome 2q and alterations of the caspase 8 gene in neuroblastoma. Oncogene 2001; 20:4424-32. [PMID: 11466626 DOI: 10.1038/sj.onc.1204521] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2001] [Revised: 04/05/2001] [Accepted: 04/09/2001] [Indexed: 11/09/2022]
Abstract
We previously reported a high incidence of loss of heterozygosity (LOH) on chromosome 2q33 in neuroblastoma (NB), observed in various types of human cancers including lung cancer, head and neck cancer and follicular thyroid carcinoma. To better elucidate the role of chromosome 2q aberrations in NB, we examined common allelic imbalance (AI) regions on chromosome 2q in 82 NB patients using 10 polymorphic microsatellite markers. AI on 2q was detected in 26 (32%) of 82 NB cases. There was a distinct common AI region between the D2S115 and D2S307 markers on 2q33. The distance between these markers was about 2.0 cM. Recently, the caspase 8 and caspase 10 genes, both of which encode cystein protease, were mapped to chromosome 2q33. Since the common AI region on 2q33 includes the caspase 8 and caspase 10 genes, the alterations of these genes were examined further. Absent or reduced expression of caspase 8 and caspase 10 were found in 19 (70%) of 27 and two (7%) of 27 NB cell lines by reverse transcription-polymerase chain reaction, respectively. A missense mutation was detected at codon 96, GCT (Alanine) to GTT (Valine), of the caspase 8 gene in one of the NB cell lines lacking caspase 8 expression. Thirteen (68%) of 19 cell lines lacking caspase 8 expression displayed methylation of the CpG island of the caspase 8 gene, whereas only one (13%) of eight cell lines with caspase 8 expression showed caspase 8 methylation (P=0.031). Furthermore, there was a significant association between AI at 2q33 and loss of caspase 8 expression (P=0.026). These results indicated that there was a tumor suppressor gene in the common AI region on chromosome 2q33 involved in the pathogenesis of a subset of NB. It is possible that the caspase 8 gene is one of the candidate tumor suppressor genes for NB and inactivation of this gene plays an important role in the tumorigenesis of NB through mainly its methylation.
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Affiliation(s)
- J Takita
- Department of Pediatrics, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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20
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Takita J, Yang HW, Bessho F, Hanada R, Yamamoto K, Kidd V, Teitz T, Wei T, Hayashi Y. Absent or reduced expression of the caspase 8 gene occurs frequently in neuroblastoma, but not commonly in Ewing sarcoma or rhabdomyosarcoma. Med Pediatr Oncol 2000; 35:541-3. [PMID: 11107112 DOI: 10.1002/1096-911x(20001201)35:6<541::aid-mpo9>3.0.co;2-t] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PROCEDURE To clarify whether the caspase 8 gene is involved in the pathogenesis of neuroblastoma (NB), we examined alterations of the caspase 8 gene in 15 NB, seven Ewing sarcoma (ES), and eight rhabdomyosarcoma (RMS) cell lines, using reverse transcription-polymerase chain reaction (RT-PCR) and RT-PCR single-strand conformation polymorphism (SSCP) analyses. RESULTS The caspase 8 gene was not expressed in 11 (73%) of 15 NB cell lines, it was absent in only one of seven ES cell lines, but was present in all eight RMS cell lines examined. No mutations were detected in any cell lines examined. CONCLUSIONS Inactivation of the caspase 8 gene is considered to be involved in the pathogenesis of NB, but not ES or RMS.
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Affiliation(s)
- J Takita
- Department of Pediatrics, Faculty of Medicine, University of Tokyo, Tokyo, Japan
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21
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Abstract
Much of the proteolysis that occurs during apoptosis is directed by caspases, a family of related cysteinyl proteases. A relatively small number of cellular proteins are targeted by caspases, yet their function is dramatically affected and apoptosis is triggered. Other proteases, such as granzymes and calpain, are also involved in the apoptotic signaling process, but in a much more cell type- and/or stimulus type-specific manner. At least three distinct caspase-signaling pathways exist; one activated through ligand-dependent death receptor oligomerization, the second through mitochondrial disruption, and the third through stress-mediated events involving the endoplasmic reticulum. These pathways also appear to interact to amplify weak apoptotic signals and shorten cellular execution time. Finally, defects in caspases contribute to autoimmune disease, cancer and certain neurological disorders.
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Affiliation(s)
- V J Kidd
- Department of Tumor Cell Biology, St Jude Children's Research Hospital, Memphis, TN 38101, USA
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22
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Teitz T, Wei T, Valentine MB, Vanin EF, Grenet J, Valentine VA, Behm FG, Look AT, Lahti JM, Kidd VJ. Caspase 8 is deleted or silenced preferentially in childhood neuroblastomas with amplification of MYCN. Nat Med 2000; 6:529-35. [PMID: 10802708 DOI: 10.1038/75007] [Citation(s) in RCA: 551] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Caspase 8 is a cysteine protease regulated in both a death-receptor-dependent and -independent manner during apoptosis. Here, we report that the gene for caspase 8 is frequently inactivated in neuroblastoma, a childhood tumor of the peripheral nervous system. The gene is silenced through DNA methylation as well as through gene deletion. Complete inactivation of CASP8 occurred almost exclusively in neuroblastomas with amplification of the oncogene MYCN. Caspase 8-null neuroblastoma cells were resistant to death receptor- and doxorubicin-mediated apoptosis, deficits that were corrected by programmed expression of the enzyme. Thus, caspase 8 acts as a tumor suppressor in neuroblastomas with amplification of MYCN.
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Affiliation(s)
- T Teitz
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, Tennessee 38101, USA
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23
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Abstract
The human CASP8 gene, whose product is also known as caspase 8 and FLICE, encodes an interleukin-1beta converting enzyme (ICE)-related cysteine protease that is activated by the engagement of several different death receptors. Caspase 8 is immediately recruited to the Fas receptor once it oligomerizes, and its protease activity is crucial for the apoptotic response generated by the resulting death-inducing signaling complex (DISC). We report here that the CASP8 gene contains at least 11 exons spanning approximately 30kb on human chromosome band 2q33-34. This region of human chromosome 2 was previously reported as the location of the CASP10 gene, whose product is closely related to caspase 8. Chromosome 2 band q33-34 is also involved in tumorigenesis, with loss of heterogeneity (LOH) being reported in a number of tumors. We also report EcoRI and HindIII polymorphisms that may prove to be useful in disease analysis. Both caspases 8 and 10 contain long pro-domains with duplicated death effector domains (DEDs), as well as their corresponding cysteine protease catalytic domains. Thus, it appears that CASP8 and CASP10 have evolved by tandem gene duplication, much like the CASP1, CASP4 and CASP5 gene cluster on human chromosome 11q22.2-22.3.
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Affiliation(s)
- J Grenet
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis TN 38101, USA
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24
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Siegel DS, Zhang X, Feinman R, Teitz T, Zelenetz A, Richon VM, Rifkind RA, Marks PA, Michaeli J. Hexamethylene bisacetamide induces programmed cell death (apoptosis) and down-regulates BCL-2 expression in human myeloma cells. Proc Natl Acad Sci U S A 1998; 95:162-6. [PMID: 9419346 PMCID: PMC18160 DOI: 10.1073/pnas.95.1.162] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Multiple myeloma (MM) is a B cell malignancy characterized by the expansion of monoclonal Ig-secreting plasma cells with low proliferative activity. It is postulated that inhibition of physiologic cell death is an underlying factor in the pathophysiology of MM. The development of chemoresistance is a common feature in patients with MM. In the present studies, hexamethylene bisacetamide (HMBA), a hybrid polar compound that is a potent inducer of terminal differentiation of various transformed cells, is shown to inhibit the growth of several human myeloma cell lines (ARP-1, U266, and RPMI 8226), including doxorubicin-resistant RPMI 8226 variants that overexpress the multidrug-resistance gene, MDR-1, and its product, p-glycoprotein. In addition to growth arrest and suppression of clonogenicity, HMBA induces apoptosis both in freshly isolated human myeloma cells and in cell lines, as determined by morphologic alterations, cell cycle distribution and endonucleosomal DNA fragmentation. Further, HMBA decreases BCL-2 protein expression in myeloma cells within 12-48 hr. Overexpression of BCL-2 protein in ARP-1 cells confers resistance to HMBA-induced apoptosis. Taken together, these data suggest that HMBA is a potent inducer of apoptosis in human myeloma cells, which may act through suppressing the anti-apoptotic function of the bcl-2 gene. HMBA, and related hybrid polar compounds, may prove useful in the management of this presently incurable disease.
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Affiliation(s)
- D S Siegel
- Program of Cell Biology, The University of Arkansas, Little Rock, AR 72205, USA
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Teitz T, Chang JC, Kan YW, Yen TS. Thymic epithelial neoplasms in transgenic mice expressing SV40 T antigen under the control of an erythroid-specific enhancer. J Pathol 1995; 177:309-15. [PMID: 8551394 DOI: 10.1002/path.1711770314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The beta-globin locus control region is known to be a powerful erythroid-specific enhancer. In an attempt to produce immortalized erythroid percursor cells, transgenic mice have been generated with the simian virus (SV) 40 T antigen gene under the control of the locus control region. As previously reported, transgenic mice did not develop erythroleukaemia, but rather succumbed to insulinomas and poorly differentiated rhabdomyosarcomas. This paper describes additional mice containing this transgene that developed thymomas of the mixed epithelial/lymphocytic type, in which only the epithelial component expressed the T antigen. Epithelial cell lines have been established from these tumours. This system may be useful in future studies on the pathogenesis of thymomas and the function of thymic epithelial cells.
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Affiliation(s)
- T Teitz
- Howard Hughes Medical Institute, University of California, San Francisco 94143-0724, USA
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Teitz T, Yen TS, Kan YW. Amplification of a SV40 T antigen transgene is associated with sarcomagenesis in mice. Carcinogenesis 1994; 15:2049-51. [PMID: 7923601 DOI: 10.1093/carcin/15.9.2049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Transgenic mice harboring simian virus 40 large T antigen (Tag) gene fused to an erythroid-specific enhancer developed soft tissue sarcomas which expressed very high levels of T antigen. The Tag expression was not detectable in the animals' non-transformed tissues. While mice bearing several copies of the transgene developed tumors at an early age of 4-6 months, those with a single copy had a delayed onset of 10-16 months, and DNA analysis of their tumors showed amplification of the Tag transgene. Amplification of a Tag transgene has also been described previously in brain tumors. Our studies demonstrate that Tag transgene amplification is not restricted to a particular construct or a single tumor type. Therefore, this may be a general mechanism for Tag-mediated carcinogenesis, and our transgenic mouse system can be useful for elucidating the mechanisms that govern the amplification process of Tag sequences in vivo.
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MESH Headings
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Blotting, Southern
- Cloning, Molecular
- DNA, Neoplasm/analysis
- DNA, Neoplasm/genetics
- Gene Amplification
- Genes, Viral
- Globins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutagenesis, Insertional
- Repetitive Sequences, Nucleic Acid
- Sarcoma, Experimental/genetics
- Simian virus 40/genetics
- Simian virus 40/immunology
- Time Factors
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Affiliation(s)
- T Teitz
- Howard Hughes Medical Institute, University of California, San Francisco 94143-0724
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Teitz T, Yen TS, Chang JC, Kan YW. SV40 T antigen directed by a powerful erythroid enhancer-promoter produced sarcomas and pancreatic tumors but not erythroid-specific tumors in transgenic mice. DNA Cell Biol 1994; 13:705-10. [PMID: 7772251 DOI: 10.1089/dna.1994.13.705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have expressed the simian virus 40 (SV40) large T antigen oncogene in erythroid tissues of mice to test its ability to immortilize erythroid cells. A transgene construct was built in which the SV40 large T antigen structural gene was linked to erythroid-specific enhancer and promoter sequences. The enhancer employed was the human beta-globin family microlocus control region, and the promoter sequences were derived from the human beta-globin promoter. Transgenic mice were generated and they expressed T antigen in the bone marrow and spleen cells. Yet, no hematopoietic neoplasia arose in these mice. Instead, after a lag period of 2-6 months, the mice developed soft tissue sarcomas and pancreatic islet-cell tumors that expressed high levels of T antigen.
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Affiliation(s)
- T Teitz
- Howard Hughes Medical Institute, University of California, San Francisco 94143-0724, USA
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Teitz T, Chang JC, Kitamura M, Yen TS, Kan YW. Rhabdomyosarcoma arising in transgenic mice harboring the beta-globin locus control region fused with simian virus 40 large T antigen gene. Proc Natl Acad Sci U S A 1993; 90:2910-4. [PMID: 7681991 PMCID: PMC46206 DOI: 10.1073/pnas.90.7.2910] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The beta-globin locus control region (LCR) confers a high level of erythroid-specific and copy-number-dependent expression to human globin genes in transgenic mice. Simian virus 40 T (tumor) antigen (Tag) with its own natural enhancer causes choroid plexus tumors in mice. We investigated the effect of the LCR on Tag gene expression, reasoning that mice harboring a LCR-Tag fusion gene might develop hematopoietic malignancies. To test this hypothesis we introduced an enhancerless Tag gene downstream of a LCR cassette into the germ lines of mice. The phenotypes of the transgenic mice depended on the copy number of the transgene. While mice with 1-2 copies matured normally, those with 3-7 copies developed rhabdomyosarcomas in different anatomic sites at high frequency and showed hyperplasia of the pancreatic islet cells which progressed to pancreatic islet tumors. In addition, the mice bearing 7 copies of the transgene had hypoglycemia and were stunted in growth. Mice with more than 10 copies were markedly stunted in growth and died within 2-4 weeks. Tag expression was detected at high levels in the mouse tumors but not in any other tissues, including the hematopoietic cells.
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Affiliation(s)
- T Teitz
- Howard Hughes Medical Institute, San Francisco, CA
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Affiliation(s)
- T L Yang-Feng
- Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510
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Teitz T, Eli D, Penner M, Bakhanashvili M, Naiman T, Timme TL, Wood CM, Moses RE, Canaani D. Expression of the cDNA for the beta subunit of human casein kinase II confers partial UV resistance on xeroderma pigmentosum cells. Mutat Res 1990; 236:85-97. [PMID: 1694965 DOI: 10.1016/0921-8777(90)90036-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
An immortalized xeroderma pigmentosum cell line belonging to the complementation group D (XP-D) was transfected with a normal human cDNA clone library constructed in a mammalian expression vector. Following UV-irradiation-selection, a transformant having a stable, partially UV-resistant phenotype was isolated. A transfected cDNA of partial length was rescued from the transformant's cellular DNA by in vitro amplification, using expression-vector specific oligonucleotides as primers in a polymerase chain reaction (PCR). Expression of this cDNA complemented the UV sensitivity of the XP-D cell line to the UV-resistance levels characteristic of the primary transformant. The nucleotide sequence of the cDNA was determined. The deduced protein identified the cDNA as encoding for the beta subunit of casein kinase II (CKII-beta). Similar to the effect exerted by the truncated CKII-beta cDNA, expression of a cDNA clone encompassing the complete translated region of CKII-beta leads to XP-D cells partially resistant to UV-irradiation. However, transfection of CKII-beta cDNA could also partially complement the UV-sensitivity of a xeroderma pigmentosum cell line belonging to group C (XP-C). Analysis by Southern, Northern and RNAase mismatch cleavage techniques did not reveal any functional defect in the CKII-beta gene of cell lines derived from either 7 XP-D or 10 XP-C families. We therefore consider it unlikely that either the XP-D or the XP-C DNA repair deficiency is associated with a defect in the beta subunit of casein kinase II. Nevertheless, our findings suggest the possibility that the cell's response to DNA damage is modulated by CKII-dependent protein phosphorylation.
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Affiliation(s)
- T Teitz
- Department of Biochemistry, Tel Aviv University, Ramat Aviv, Israel
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Teitz T, Penner M, Eli D, Stark M, Bakhanashvili M, Naiman T, Canaani D. Isolation by polymerase chain reaction of a cDNA whose product partially complements the ultraviolet sensitivity of xeroderma pigmentosum group C cells. Gene 1990; 87:295-8. [PMID: 2332174 DOI: 10.1016/0378-1119(90)90316-j] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A xeroderma pigmentosum (XP) cell line from complementation group C has been complemented to attain ultraviolet (UV) resistance and DNA repair proficiency, by transfection with a human expression cDNA library, followed by selection to UV resistance. We now show that the transfected cDNAs can be rescued from cellular DNA of a secondary transformant by its in vitro amplification using expression-vector-specific oligodeoxyribonucleotides as primers in a polymerase chain reaction. The amplified cDNAs were cloned into a mammalian expression vector. Their transfection into XP cells identified a single cDNA which specifically complemented the UV sensitivity of a group-C-derived cell line to the same partial UV-resistance levels exhibited by the transformant from which the cDNAs were rescued.
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Affiliation(s)
- T Teitz
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
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Teitz T, Naiman T, Avissar SS, Bar S, Okayama H, Canaani D. Complementation of the UV-sensitive phenotype of a xeroderma pigmentosum human cell line by transfection with a cDNA clone library. Proc Natl Acad Sci U S A 1987; 84:8801-4. [PMID: 3480511 PMCID: PMC299638 DOI: 10.1073/pnas.84.24.8801] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In previous work, a xeroderma pigmentosum cell line belonging to complementation group C was established by transformation with origin-defective simian virus 40. We now report the complementation of the UV sensitivity of this cell line by gene transfer. A human cDNA clone library constructed in a mammalian expression vector, and itself incorporated in a lambda phage vector, was introduced into the cells as a calcium phosphate precipitate. Following selection to G418 resistance, provided by the neo gene of the vector, transformants were selected for UV resistance. Twenty-one cell clones were obtained with UV-resistance levels typical of normal human fibroblasts. All transformants contained vector DNA sequences in their nuclei. Upon further propagation in the absence of selection for G418 resistance, about half of the primary transformants remained UV-resistant. Secondary transformants were generated by transfection with a partial digest of total chromosomal DNA from one of these stable transformants. This resulted in 15 G418-resistant clones, 2 of which exhibited a UV-resistant phenotype. The other primary clones lost UV resistance rapidly when subcultured in the absence of G418. Importantly, several retained UV resistance under G418 selection pressure. The acquisition of UV resistance by secondary transformants derived by transfection of DNA from a stable primary transformant, and the linkage between G418 and UV resistances in the unstable primary transformants, strongly suggests that the transformants acquired UV resistance through DNA-mediated gene transfer and not by reversion.
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Affiliation(s)
- T Teitz
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel
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Canaani D, Naiman T, Teitz T, Berg P. Immortalization of xeroderma pigmentosum cells by simian virus 40 DNA having a defective origin of DNA replication. Somat Cell Mol Genet 1986; 12:13-20. [PMID: 3003928 DOI: 10.1007/bf01560723] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A simian virus 40 (SV40) DNA fragment, encompassing the whole early region and having a defective origin of DNA replication, has been used to transform human fibroblast cells derived from two xeroderma pigmentosum (XP) patients. Two of the SV40-transformed XP cell lines, belonging to complementation group C, had acquired the characteristic of indefinite life-span in culture. These XP cell lines synthesize T antigen as shown by immunofluorescence and retain the high sensitivity to UV irradiation. Detailed karyotype analysis shows very few chromosomal changes, while the transfecting SV40 DNA is integrated into cellular DNA sequences. These are the first immortalized XP cell lines derived from complementation group C. In view of the extreme difficulty in obtaining immortalized human fibroblasts, we suggest a possible advantage of replication defective SV40 DNA molecules for immortalizing human fibroblast cells of any source.
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