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Liu L, Wang H, Cui J, Zhang Q, Zhang W, Xu W, Lu H, Liu S, Shen S, Fang F, Li L, Yang W, Zhuang Z, Li J. Inhibition of Protein Phosphatase 2A Sensitizes Mucoepidermoid Carcinoma to Chemotherapy via the PI3K-AKT Pathway in Response to Insulin Stimulus. Cell Physiol Biochem 2018; 50:317-331. [PMID: 30282066 DOI: 10.1159/000494008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 09/25/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND/AIMS Protein phosphatase 2A (PP2A) is a ubiquitous serine/threonine phosphatase that mediates cell cycle regulation and metabolism. Mounting evidence has indicated that PP2A inhibition exhibits considerable anticancer potency in multiple types of human cancers. However, the efficacy of PP2A inhibition remains unexplored in mucoepidermoid carcinoma (MEC), especially in locally advanced and metastatic cases with limited systemic treatment. In this study, we demonstrated the therapeutic potency of LB100 in mucoepidermoid carcinoma. METHODS In this study, the expression of PP2A was evaluated using immunohistochemical (IHC) staining. The effects associated with LB100 alone and in combination with cisplatin for the treatment of mucoepidermoid carcinoma were investigated both in vitro, regarding metabolism, proliferation, and migration, and in vivo in a mucoepidermoid carcinoma xenograft model. In addition, with LB100 treatment and in response to an insulin stimulus, the expression levels and phosphorylation levels of targets in the PI3K-AKT pathway were determined using western blot analysis and immunoblotting. RESULTS The expression of protein phosphatase 2A was significantly upregulated in the clinical specimens of high-grade MECs compared with those of low-/medium-grade MECs and normal controls. In this article, we report that a small molecule PP2A inhibitor, LB100, decreased cellular viability and glycolytic activity and induced G2/M cell cycle arrest. Importantly, LB100 enhanced the efficacy of cisplatin in mucoepidermoid carcinoma cells both in vitro and in vivo. PP2A inhibition by LB100 increased the phosphorylation of insulin receptor substrate 1(IRS-1) on serine residues, downregulated the expression of phosphatidylinositol 3-kinase (PI3K) p110 alpha subunit and dephosphorylated AKT at Ser473 and Thr308 in mucoepidermoid carcinoma cells in response to insulin stimulus. CONCLUSION These results highlight the translational potential of PP2A inhibition to synergize with cisplatin in mucoepidermoid carcinoma treatment.
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Affiliation(s)
- Limin Liu
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.,Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Herui Wang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jing Cui
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Qi Zhang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Wei Zhang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Wanlin Xu
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Hao Lu
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Shengwen Liu
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Shukun Shen
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | | | - Lei Li
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Wenjun Yang
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
| | - Zhengping Zhuang
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jiang Li
- Department of Oral Pathology, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, National Clinical Research Center for Oral Diseases, Shanghai, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China
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Lai D, Chen M, Su J, Liu X, Rothe K, Hu K, Forrest DL, Eaves CJ, Morin GB, Jiang X. PP2A inhibition sensitizes cancer stem cells to ABL tyrosine kinase inhibitors in BCR-ABL
+
human leukemia. Sci Transl Med 2018; 10. [DOI: 10.1126/scitranslmed.aan8735] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
PP2A inhibitors and BCR-ABL inhibitors synergize to kill drug-insensitive leukemia cells.
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Affiliation(s)
- Damian Lai
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Min Chen
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Jiechuang Su
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Xiaohu Liu
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Katharina Rothe
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Kaiji Hu
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Donna L. Forrest
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Leukemia/Bone Marrow Transplant Program of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
| | - Connie J. Eaves
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
| | - Gregg B. Morin
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
- Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
| | - Xiaoyan Jiang
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
- Department of Medicine, University of British Columbia, Vancouver, British Columbia V5Z 1M9, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6H 3N1, Canada
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Chung V, Mansfield AS, Braiteh F, Richards D, Durivage H, Ungerleider RS, Johnson F, Kovach JS. Safety, Tolerability, and Preliminary Activity of LB-100, an Inhibitor of Protein Phosphatase 2A, in Patients with Relapsed Solid Tumors: An Open-Label, Dose Escalation, First-in-Human, Phase I Trial. Clin Cancer Res 2016; 23:3277-3284. [PMID: 28039265 DOI: 10.1158/1078-0432.ccr-16-2299] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 11/16/2022]
Abstract
Purpose: To determine the MTD and to assess the safety, tolerability, and potential activity of LB-100, a first-in-class small-molecule inhibitor of protein phosphatase 2A (PP2A) in adult patients with progressive solid tumors.Experimental Design: LB-100 was administered intravenously daily for 3 days in 21-day cycles in a 3 + 3 dose escalation design.Results: There were 29 patient entries over 7 dose escalations. One patient stopped treatment after one dose because of an acute infection and was reenrolled after recovery; each course was analyzed as a separate patient entry. Two patients had dose-limiting toxicity (reversible increases in serum creatinine or calculated serum creatinine clearance) at the 3.1 mg/m2 level. Probable or possible study drug-related grade 3 adverse events occurred in 6 (20.7%) patients [anemia (n = 2), decreased creatinine clearance, dyspnea, hyponatremia, and lymphopenia]. Ten (50%) of 20 response-evaluable patients had stable disease for four or more cycles. One patient with pancreatic adenocarcinoma had a partial response noted after 10 cycles, which was maintained for five additional cycles. The other patients achieving stable disease had one of the following: fibrosarcoma, chondrosarcoma, thymoma, atypical carcinoid of lung, or ovarian, testicular, breast (n = 2), and prostate cancer. The recommended phase II dose of LB-100 is 2.33 mg/m2 daily for 3 days every 3 weeks.Conclusions: The safety, tolerability, preliminary evidence of antitumor activity, and novel mechanism of action of LB-100 support its continued development alone and in combination with other therapies. Clin Cancer Res; 23(13); 3277-84. ©2016 AACR.
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Affiliation(s)
| | | | - Fadi Braiteh
- Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada.,US Oncology Research, The Woodlands, Texas
| | - Donald Richards
- US Oncology Research, The Woodlands, Texas.,Texas Oncology, Tyler, Texas
| | | | | | | | - John S Kovach
- Lixte Biotechnology Holdings, Inc., East Setauket, New York.
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4
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Cong Y, Wang L, Wang Z, He S, Zhou D, Jing X, Huang Y. Enhancing Therapeutic Efficacy of Cisplatin by Blocking DNA Damage Repair. ACS Med Chem Lett 2016; 7:924-928. [PMID: 27774130 PMCID: PMC5066156 DOI: 10.1021/acsmedchemlett.6b00236] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 08/24/2016] [Indexed: 12/18/2022] Open
Abstract
Self-repair of nuclear DNA damage is the most known reason that leads to drug resistance of cancer tissue and limited therapeutic efficacy of anticancer drugs. Inhibition of protein phosphatase 2A (PP2A) would block DNA damage-induced defense of cancer cells to suppress DNA repair for enhanced cancer treatment. Here, we combined a PP2A inhibitor LB (4-(3-carboxy-7-oxa-bicyclo[2.2.1]heptane-2-carbonyl) piperazine-1-carboxylic acid tert-butyl ester) and the DNA damage chemotherapeutic drug cisplatin through a simple physical superposition. The two drugs administrated at a ratio of 1:1 exhibited an optional synergistic antitumor efficacy in vitro and in vivo. LB was demonstrated to specifically activate the protein kinase B (Akt) and mitogen-activated protein kinases (MAPK) signaling pathways by PP2A inhibition to overcome cell cycle arrest caused by cisplatin-induced DNA damage.
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Affiliation(s)
- Yuwei Cong
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R.
China
| | - Liangyan Wang
- Nanjing
Orientleader Technology Co., Ltd., Nanjing 210028, P. R.
China
| | - Zigui Wang
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R.
China
| | - Shasha He
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
- University
of Chinese Academy of Sciences, Beijing 100049, P. R.
China
| | - Dongfang Zhou
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Xiabin Jing
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Yubin Huang
- State Key
Laboratory of Polymer Physics and Chemistry, Changchun Institute of
Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
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5
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Lv P, Wang Y, Ma J, Wang Z, Li JL, Hong CS, Zhuang Z, Zeng YX. Inhibition of protein phosphatase 2A with a small molecule LB100 radiosensitizes nasopharyngeal carcinoma xenografts by inducing mitotic catastrophe and blocking DNA damage repair. Oncotarget 2015; 5:7512-24. [PMID: 25245035 PMCID: PMC4202140 DOI: 10.18632/oncotarget.2258] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC), while uncommon worldwide, is a major health problem in China. Although local radiation and surgery provide good control of NPC, better treatments that permit reductions in radiation dosing are needed. Inhibition of protein phosphatase 2A (PP2A), a ubiquitous multifunctional enzyme with critical roles in cell cycle regulation and DNA-damage response, reportedly sensitizes cancer cells to radiation and chemotherapy. We studied PP2A inhibition with LB100, a small molecule currently in a Phase I clinical trial, on radiosensitization of two human nasopharyngeal cell lines: CNE1, which is reportedly radioresistant, and CNE2. In both cell lines, LB100 exposure increased intracellular p-Plk1, TCTP, and Cdk1 and decreased p53, changes associated with cell cycle arrest, mitotic catastrophe and radio-inhibition of cell proliferation. Mice bearing subcutaneous xenografts of either cell line were administered 1.5 mg/kg LB100 daily for three days and a single dose of 20 Gy radiation (day 3), which produced marked and prolonged tumor mass regression (dose enhancement factors of 2.98 and 2.27 for CNE1 and CNE2 xenografts, respectively). Treatment with either LB100 or radiation alone only transiently inhibited xenograft growth. Our results support further exploration of PP2A inhibition as part of radiotherapy regimens for NPC and potentially other solid tumors.
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Affiliation(s)
- Peng Lv
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China. Beijing Neurosurgical Institute, Capital Medical University, Beijing, People's Republic of China
| | - Yue Wang
- Institute for Medical Device Standardization Administration, National Institutes for Food and Drug Control, Beijing , People's Republic of China
| | - Jie Ma
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China
| | - Zheng Wang
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China
| | - Jing-Li Li
- Institute for Medical Device Standardization Administration, National Institutes for Food and Drug Control, Beijing , People's Republic of China
| | - Christopher S Hong
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD ,USA
| | - Zhengping Zhuang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD ,USA
| | - Yi-Xin Zeng
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China. Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong , People's Republic of China. State Key Laboratory of Oncology in Southern China, Guangzhou, Guangdong , People's Republic of China
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6
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Zhang C, Hong CS, Hu X, Yang C, Wang H, Zhu D, Moon S, Dmitriev P, Lu J, Chiang J, Zhuang Z, Zhou Y. Inhibition of protein phosphatase 2A with the small molecule LB100 overcomes cell cycle arrest in osteosarcoma after cisplatin treatment. Cell Cycle 2015; 14:2100-8. [PMID: 25942376 DOI: 10.1080/15384101.2015.1041693] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Osteosarcoma is the most common primary malignant bone tumor and affects a significant portion of pediatric oncology patients. Although surgery and adjuvant chemotherapy confer significant survival benefits, many patients go on to develop metastatic disease, particularly to the lungs, secondary to development of drug resistance. Inhibition of protein phosphatase 2A with the small molecule, LB100, has demonstrated potent chemo- and radio-sensitizing properties in numerous pre-clinical tumor models. In this study, we showed that LB100 overcame DNA repair mechanisms in osteosarcoma cells treated with cisplatin, in vitro, and recapitulated these findings in an in vivo xenograft model. Notably, the addition of LB100 to cisplatin prevented development of pulmonary metastases in the majority of treated animals. Our data indicated the mechanism of chemo-sensitization by LB100 involved abrogation of the ATM/ATR-activated DNA damage response, leading to hyperphosphorylation of Chk proteins and persistent cyclin activity. In addition, LB100 exposure suppressed Akt signaling, leading to Mdm2-mediated proteasomal degradation of functional p53. Taken together, LB100 prevented repair of cisplatin-induced DNA damage, resulting in mitotic catastrophe and cell death.
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Affiliation(s)
- Chao Zhang
- a Department of Orthopedics; Xinqiao Hospital; Third Military Medical University ; Chongqing , China
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7
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Bai X, Zhi X, Zhang Q, Liang F, Chen W, Liang C, Hu Q, Sun X, Zhuang Z, Liang T. Inhibition of protein phosphatase 2A sensitizes pancreatic cancer to chemotherapy by increasing drug perfusion via HIF-1α-VEGF mediated angiogenesis. Cancer Lett 2014; 355:281-7. [PMID: 25304380 DOI: 10.1016/j.canlet.2014.09.048] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 12/18/2022]
Abstract
Pancreatic cancer is a malignant disease without efficient treatment. Improved treatments are urgently needed to enhance or replace chemotherapy. Here we used a small molecular compound LB-100 to assess the effect of pharmacological inhibition of protein phosphatase 2A (PP2A) in combination with doxorubicin on the proliferation of pancreatic cancer in cell lines and a xenograft model. LB-100 moderately reduced PP2A activity and the growth of the cell lines but did not show chemosensitization in vitro. In vivo, however, LB-100 synergistically enhanced the activity of doxorubicin. This effect was associated with increased microvessel density, blood perfusion, and doxorubicin concentrations within the xenografts. Mechanically, LB-100 induced expression of hypoxia-induced factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). In an umbilical vein endothelial cell monolayer model for measuring changes in vascular permeability, increased VEGF secretion following exposure to LB-100 and doxorubicin was accompanied by increased amounts of doxorubicin penetrating the endothelial barrier. In conclusion, PP2A inhibition by LB-100 enhanced the cytotoxicity of doxorubicin in vivo but not in vitro potentially via HIF-1α-VEGF mediated angiogenesis. Combining inhibition of PP2A with chemotherapeutic regimens may enhance their effectiveness against pancreatic cancer.
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Affiliation(s)
- Xueli Bai
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Cancer Prevention and Intervention, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Zhi
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qi Zhang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Cancer Prevention and Intervention, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Liang
- Department of Neurosurgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Chen
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chao Liang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qida Hu
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xu Sun
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengping Zhuang
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Tingbo Liang
- Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Cancer Prevention and Intervention, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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8
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Sallman DA, Wei S, List A. PP2A: The Achilles Heal in MDS with 5q Deletion. Front Oncol 2014; 4:264. [PMID: 25295231 PMCID: PMC4172014 DOI: 10.3389/fonc.2014.00264] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 09/08/2014] [Indexed: 12/13/2022] Open
Abstract
Myelodysplastic syndromes (MDS) represent a hematologically diverse group of myeloid neoplasms, however, one subtype characterized by an isolated deletion of chromosome 5q [del(5q)] is pathologically and clinically distinct. Patients with del(5q) MDS share biological features that account for the profound hypoplastic anemia and unique sensitivity to treatment with lenalidomide. Ineffective erythropoiesis in del(5q) MDS arises from allelic deletion of the ribosomal processing S-14 (RPS14) gene, which leads to MDM2 sequestration with consequent p53 activation and erythroid cell death. Since its approval in 2005, lenalidomide has changed the natural course of the disease. Patients who achieve transfusion independence and/or a cytogenetic response with lenalidomide have a decreased risk of progression to acute myeloid leukemia and an improved overall survival compared to non-responders. Elucidation of the mechanisms of action of lenalidomide in del(5q) MDS has advanced therapeutic strategies for this disease. The selective cytotoxicity of lenalidomide in del(5q) clones derives from inhibition of a haplodeficient phosphatase whose catalytic domain is encoded within the common deleted region on chromosome 5q, i.e., protein phosphatase 2A (PP2Acα). PP2A is a highly conserved, dual specificity phosphatase that plays an essential role in regulation of the G2/M checkpoint. Inhibition of PP2Acα results in cell-cycle arrest and apoptosis in del(5q) cells. Targeted knockdown of PP2Acα using siRNA is sufficient to sensitize non-del(5q) clones to lenalidomide. Through its inhibitory effect on PP2A, lenalidomide stabilizes MDM2 to restore p53 degradation in erythroid precursors, with subsequent arrest in G2/M. Unfortunately, the majority of patients with del(5q) MDS develop resistance to lenalidomide over time associated with PP2Acα over-expression. Targeted inhibition of PP2A with a more potent inhibitor has emerged as an attractive therapeutic approach for patients with del(5q) MDS.
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Affiliation(s)
- David A Sallman
- Immunology Program and Malignant Hematology Program, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL , USA
| | - Sheng Wei
- Immunology Program and Malignant Hematology Program, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL , USA
| | - Alan List
- Immunology Program and Malignant Hematology Program, H. Lee Moffitt Cancer Center and Research Institute , Tampa, FL , USA
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Yi T, Elson P, Mitsuhashi M, Jacobs B, Hollovary E, Budd TG, Spiro T, Triozzi P, Borden EC. Phosphatase inhibitor, sodium stibogluconate, in combination with interferon (IFN) alpha 2b: phase I trials to identify pharmacodynamic and clinical effects. Oncotarget 2012; 2:1155-64. [PMID: 22201704 DOI: 10.18632/oncotarget.393] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Since sodium stibogluconate (SSG) inhibited phosphatases including SHP-1 and augmented anti-tumor actions of IFN-α2b in vitro and in mice, two Phase I trials of SSG/IFN-α2b combination were undertaken to evaluate safety and target inhibition. Escalating doses of SSG (200-1200 mg/m2) and fixed doses of IFN-α2b (3x106 units/m2) with or without chemotherapy (dacarbazine, vinblastine, cisplatin) were evaluated for side effects and impact on SHP-1 phospho-substrates and IFNα-stimulated-genes (ISGs) in peripheral blood in 40 patients with metastatic melanoma, soft tissue sarcomas, gastrointestinal stromal tumors, and breast or colorectal carcinomas who did not have other established treatment options. Common adverse events were bone marrow suppression, fatigue, gastrointestinal upset, and asymptomatic lipase elevation (n=13); the latter was dose related and mostly after 10d of SSG/IFN-α2b in combination. Levels of SHP-1 substrates (pSTAT1, pSTAT3, pLck and pSlp76) were increased (up to 3x) in peripheral blood cells following SSG with no potentiation by combination with IFN-α2b. Representative ISGs in peripheral blood were induced after IFN-α2b at 4 and 24 hrs with selective modulations by combination. The median time on trials was 2.3 months (10-281d) with no objective regression of disease. Alive at 1y were 17/40 (43%) patients and after 2y were 8/40 (20%) following treatment initiation. These data demonstrate that SSG impacted signal molecules consistent with PTP inhibition and was tolerated in combination with IFN-α2b. Phase II investigations of SSG could safely utilize doses of up to 1200 mg/m2 of SSG for up to 10d alone or in combination with IFN-α2b with or without chemotherapy.
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Affiliation(s)
- Taolin Yi
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
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10
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Taylor JR, Lehmann BD, Chappell WH, Abrams SL, Steelman LS, McCubrey JA. Cooperative effects of Akt-1 and Raf-1 on the induction of cellular senescence in doxorubicin or tamoxifen treated breast cancer cells. Oncotarget 2012; 2:610-26. [PMID: 21881167 PMCID: PMC3248208 DOI: 10.18632/oncotarget.315] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Escape from cellular senescence induction is a potent mechanism for chemoresistance. Cellular senescence can be induced in breast cancer cell lines by the removal of estrogen signaling with tamoxifen or by the accumulation of DNA damage induced by the chemotherapeutic drug doxorubicin. Long term culturing of the hormone-sensitive breast cancer cell line MCF-7 in doxorubicin (MCF-7/DoxR) reduced the ability of doxorubicin, but not tamoxifen, to induce senescence. Two pathways that are often upregulated in chemo- and hormonal-resistance are the PI3K/PTEN/Akt/mTOR and Ras/Raf/MEK/ERK pathways. To determine if active Akt-1 and Raf-1 can influence drug-induced senescence, we stably introduced activated ΔAkt-1(CA) and ΔRaf-1(CA) into drug-sensitive and doxorubicin-resistant cells. Expression of a constitutively-active Raf-1 construct resulted in higher baseline senescence, indicating these cells possessed the ability to undergo oncogene-induced-senescence. Constitutive activation of the Akt pathway significantly decreased drug-induced senescence in response to doxorubicin but not tamoxifen in MCF-7 cells. However, constitutive Akt-1 activation in drug-resistant cells containing high levels of active ERK completely escaped cellular senescence induced by doxorubicin and tamoxifen. These results indicate that up regulation of the Ras/PI3K/PTEN/Akt/mTOR pathway in the presence of elevated Ras/Raf/MEK/ERK signaling together can contribute to drug-resistance by diminishing cell senescence in response to chemotherapy. Understanding how breast cancers containing certain oncogenic mutations escape cell senescence in response to chemotherapy and hormonal based therapies may provide insights into the design of more effective drug combinations for the treatment of breast cancer.
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Affiliation(s)
- Jackson R Taylor
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University Greenville, NC 27858 USA
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Yi T, Elson P, Mitsuhashi M, Jacobs B, Hollovary E, Budd GT, Spiro T, Triozzi P, Borden EC. Phosphatase inhibitor, sodium stibogluconate, in combination with interferon (IFN) alpha 2b: phase I trials to identify pharmacodynamic and clinical effects. Oncotarget 2011; 2:1155-1164. [PMID: 22201704 PMCID: PMC3282074 DOI: 10.18632/oncotarget.563] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 12/27/2022] Open
Abstract
Since sodium stibogluconate (SSG) inhibited phosphatases including SHP-1 and augmented anti-tumor actions of IFN-α2b in vitro and in mice, two Phase I trials of SSG/IFN-α2b combination were undertaken to evaluate safety and target inhibition. Escalating doses of SSG (200-1200 mg/m2) and fixed doses of IFN-α2b (3x106 units/m2) with or without chemotherapy (dacarbazine, vinblastine, cisplatin) were evaluated for side effects and impact on SHP-1 phospho-substrates and IFNα-stimulated-genes (ISGs) in peripheral blood in 40 patients with metastatic melanoma, soft tissue sarcomas, gastrointestinal stromal tumors, and breast or colorectal carcinomas who did not have other established treatment options. Common adverse events were bone marrow suppression, fatigue, gastrointestinal upset, and asymptomatic lipase elevation (n=13); the latter was dose related and mostly after 10d of SSG/IFN-α2b in combination. Levels of SHP-1 substrates (pSTAT1, pSTAT3, pLck and pSlp76) were increased (up to 3x) in peripheral blood cells following SSG with no potentiation by combination with IFN-α2b. Representative ISGs in peripheral blood were induced after IFN-α2b at 4 and 24 hrs with selective modulations by combination. The median time on trials was 2.3 months (10-281d) with no objective regression of disease. Alive at 1y were 17/40 (43%) patients and after 2y were 8/40 (20%) following treatment initiation. These data demonstrate that SSG impacted signal molecules consistent with PTP inhibition and was tolerated in combination with IFN-α2b. Phase II investigations of SSG could safely utilize doses of up to 1200 mg/m2 of SSG for up to 10d alone or in combination with IFN-α2b with or without chemotherapy.
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Affiliation(s)
- Taolin Yi
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
- Department of Immunology of Lerner Research Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - Paul Elson
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | | | - Barbara Jacobs
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - Emese Hollovary
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - G. Thomas Budd
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - Timothy Spiro
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - Pierre Triozzi
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - Ernest C. Borden
- Taussig Cancer Institute, The Cleveland Clinic, Cleveland, OH, USA
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Martiniova L, Lu J, Chiang J, Bernardo M, Lonser R, Zhuang Z, Pacak K. Pharmacologic modulation of serine/threonine phosphorylation highly sensitizes PHEO in a MPC cell and mouse model to conventional chemotherapy. PLoS One 2011; 6:e14678. [PMID: 21339823 PMCID: PMC3038858 DOI: 10.1371/journal.pone.0014678] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 01/17/2011] [Indexed: 12/21/2022] Open
Abstract
Background The failure of cytotoxic cancer regimens to cure the most drug-resistant, well-differentiated solid tumors has been attributed to the heterogeneity of cell types that differ in their capacities for growth, differentiation, and metastases. We investigated the effect of LB1, a small molecule inhibitor of serine/threonine protein phosphatase 2A (PP2A), on its ability to inhibit a low growth fraction and highly drug-resistant solid neuroendocrine tumor, such as metastatic pheochromocytoma (PHEO). Subsequently, we evaluated the increased efficacy of chemotherapy combined with LB1. Methodology/Principal Findings The effect of LB1 and temozolomide (TMZ), a standard chemotherapeutic agent that alone only transiently suppressed the growth and regression of metastatic PHEO, was evaluated in vitro on a single PHEO cell line and in vivo on mouse model of metastatic PHEO. In the present study, we show that metastatic PHEO, for which there is currently no cure, can be eliminated by combining LB1, thereby inhibiting PP2A, with TMZ. This new treatment approach resulted in long term, disease-free survival of up to 40% of animals bearing multiple intrahepatic metastases, a disease state that the majority of patients die from. Inhibition of PP2A was associated with prevention of G1/S phase arrest by p53 and of mitotic arrest mediated by polo-like kinase 1 (Plk-1). Conclusions/Significance The elimination of DNA damage-induced defense mechanisms, through transient pharmacologic inhibition of PP2A, is proposed as a new approach for enhancing the efficacy of non-specific cancer chemotherapy regimens against a broad spectrum of low growth fraction tumors very commonly resistant to cytotoxic drugs.
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Affiliation(s)
- Lucia Martiniova
- Reproductive and Adult Endocrinology Program, Eunice Kennedy Shriver, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jie Lu
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jeffrey Chiang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marcelino Bernardo
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Laboratory Animal Sciences Program, SAIC-Frederick, NCI-Frederick, Frederick, Maryland, United States of America
| | - Russell Lonser
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Zhengping Zhuang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (KP); (ZZ)
| | - Karel Pacak
- Reproductive and Adult Endocrinology Program, Eunice Kennedy Shriver, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (KP); (ZZ)
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13
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A synthetic cantharidin analog for the enhancement of doxorubicin suppression of stem cell-derived aggressive sarcoma. Biomaterials 2010; 31:9535-43. [DOI: 10.1016/j.biomaterials.2010.08.059] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 08/24/2010] [Indexed: 11/21/2022]
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14
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Abrams SL, Steelman LS, Shelton JG, Chappell W, Bäsecke J, Stivala F, Donia M, Nicoletti F, Libra M, Martelli AM, McCubrey JA. Enhancing therapeutic efficacy by targeting non-oncogene addicted cells with combinations of signal transduction inhibitors and chemotherapy. Cell Cycle 2010; 9:1839-46. [PMID: 20436269 DOI: 10.4161/cc.9.9.11544] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The effects of inhibition of the Raf/MEK/ERK and PI3K/Akt/mTOR signaling pathways and chemotherapeutic drugs on cell cycle progression and drug sensitivity were examined in cytokine-dependent FL5.12 hematopoietic cells. We examined their effects, as these cells resemble normal hematopoietic precursor cells as they do not exhibit "oncogene-addicted" growth, while they do display "cytokine-addicted" proliferation as cytokine removal resulted in apoptosis in greater than 80% of the cells within 48 hrs. When cytokine-dependent FL5.12 cells were cultured in the presence of IL-3, which stimulated multiple proliferation and anti-apoptotic cascades, MEK, PI3K and mTOR inhibitors transiently suppressed but did not totally inhibit cell cycle progression or induce apoptosis while chemotherapeutic drugs such as doxorubicin and paclitaxel were more effective in inducing cell cycle arrest and apoptosis. Doxorubicin induced a G(1) block, while paclitaxel triggered a G(2)/M block. Doxorubicin was more effective in inducing cell death than paclitaxel. Furthermore the effects of doxorubicin could be enhanced by addition of MEK, PI3K or mTOR inhibitors. Cytokine-dependent cells which proliferate in vitro and are not "oncogene-addicted" may represent a pre-malignant stage, more refractory to treatment with targeted therapy. However, these cells are sensitive to chemotherapeutic drugs. It is important to develop methods to inhibit the growth of such cytokine-dependent cells as they may resemble the leukemia stem cell and other cancer initiating cells. These results demonstrate the enhanced effectiveness of targeting early hematopoietic progenitor cells with combinations of chemotherapeutic drugs and signal transduction inhibitors.
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Affiliation(s)
- Stephen L Abrams
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA
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Abrams SL, Steelman LS, Shelton JG, Wong EWT, Chappell WH, Bäsecke J, Stivala F, Donia M, Nicoletti F, Libra M, Martelli AM, McCubrey JA. The Raf/MEK/ERK pathway can govern drug resistance, apoptosis and sensitivity to targeted therapy. Cell Cycle 2010; 9:1781-91. [PMID: 20436278 DOI: 10.4161/cc.9.9.11483] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The effects of the Raf/MEK/ERK and PI3K/PTEN/Akt/mTOR signaling pathways on proliferation, drug resistance, prevention of apoptosis and sensitivity to signal transduction inhibitors were examined in FL/DeltaAkt-1:ER*(Myr(+)) + DeltaRaf-1:AR cells which are conditionally-transformed to grow in response to Raf and Akt activation. Drug resistant cells were isolated from FL/DeltaAkt-1:ER*(Myr(+)) + DeltaRaf-1:AR cells in the presence of doxorubicin. Activation of Raf-1, in the drug resistant FL/DeltaAkt-1:ER*(Myr(+)) + DeltaRaf-1:AR cells, increased the IC(50) for doxorubicin 80-fold, whereas activation of Akt-1, by itself, had no effect on the doxorubicin IC50. However, Akt-1 activation enhanced cell proliferation and clonogenicity in the presence of chemotherapeutic drugs. Thus the Raf/MEK/ERK pathway had profound effects on the sensitivity to chemotherapeutic drugs, and Akt-1 activation was required for the long term growth of these cells as well as resistance to chemotherapeutic drugs. The effects of doxorubicin on the induction of apoptosis in the drug resistant cells were enhanced by addition of either mTOR and MEK inhibitors. These results indicate that targeting the Raf/MEK/ERK and PI3K/Akt/mTOR pathways may be an effective approach for therapeutic intervention in drug resistant cancers that have mutations activating these cascades.
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Affiliation(s)
- Stephen L Abrams
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA
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Yang D, Ylipaa A, Yang J, Hunt K, Pollock R, Trent J, Yli-Harja O, Shmulevich I, Nykter M, Zhang W. An integrated study of aberrant gene copy number and gene expression in GIST and LMS. Technol Cancer Res Treat 2010; 9:171-8. [PMID: 20218739 DOI: 10.1177/153303461000900206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Increased chromosomal instability that alters the gene copy numbers throughout the genome is known to have a role in molecular pathogenesis of tumors. The impact of gene dosage effect to the expression levels of genes in GIST and LMS is unknown. In this paper, we used a combination of array comparative genomic hybridization (aCGH) and gene expression data to gain insights into the interplay of structural and functional changes of the genome in GIST and LMSs. We identified specific target genes that change their expression due to the gene dosage effect. Statistical analysis identified four chromosomal regions, 1p, 14q, 15q, and 22q, where both copy number and mRNA expression were significantly different between the tumor types. Multi-dimensional scaling (MDS) analysis showed that the gene expression profiles of these four regions accurately distinguish GIST and LMS. In addition, the gene dosage sensitive genes in these regions are differently involved in several tumor growth promoting pathways, implying that there are different mechanisms underlying the GIST and LMS carcinogenesis. Integration of aCGH and gene expression data has not only provided insights into how DNA copy number variations affect the gene expression patterns in these cancers, but also proves to be a promising method to choose biologically relevant biomarkers.
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Affiliation(s)
- Da Yang
- Department of Pathology, Sarcoma Medical Oncology The University of Texas M. D. Anderson Cancer Center, Houston Texas, USA
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