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Poh AR, Ernst M. Functional roles of SRC signaling in pancreatic cancer: Recent insights provide novel therapeutic opportunities. Oncogene 2023:10.1038/s41388-023-02701-x. [PMID: 37120696 DOI: 10.1038/s41388-023-02701-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/19/2023] [Indexed: 05/01/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant disease with a 5-year survival rate of <10%. Aberrant activation or elevated expression of the tyrosine kinase c-SRC (SRC) is frequently observed in PDAC and is associated with a poor prognosis. Preclinical studies have revealed a multifaceted role for SRC activation in PDAC, including promoting chronic inflammation, tumor cell proliferation and survival, cancer cell stemness, desmoplasia, hypoxia, angiogenesis, invasion, metastasis, and drug resistance. Strategies to inhibit SRC signaling include suppressing its catalytic activity, inhibiting protein stability, or by interfering with signaling components of the SRC signaling pathway including suppressing protein interactions of SRC. In this review, we discuss the molecular and immunological mechanisms by which aberrant SRC activity promotes PDAC tumorigenesis. We also provide a comprehensive update of SRC inhibitors in the clinic, and discuss the clinical challenges associated with targeting SRC in pancreatic cancer.
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Affiliation(s)
- Ashleigh R Poh
- Olivia Newton-John Cancer Research Institute and La Trobe University School of Cancer Medicine, Melbourne, VIC, 3084, Australia.
| | - Matthias Ernst
- Olivia Newton-John Cancer Research Institute and La Trobe University School of Cancer Medicine, Melbourne, VIC, 3084, Australia.
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2
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Li ZY, Sun XY. Recent progress in SRC targeted therapy for pancreatic cancer. Shijie Huaren Xiaohua Zazhi 2021; 29:621-627. [DOI: 10.11569/wcjd.v29.i12.621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer (PC) is a highly lethal malignancy with a 5-year survival rate of only 10% and is extremely resistant to chemotherapy. Therefore, developing effective therapeutic drugs is urgently needed. SRC is a proto-oncogenic tyrosine protein kinase and highly expressed in more than 70% of PCs. SRC is involved in regulating the proliferation, infiltration, and metastasis of PC cells as well as tumor angiogenesis, thus representing one of the most promising molecular targets for developing novel drugs. Preclinical studies demonstrate that small-molecule SRC inhibitors display significant anti-cancer activities in vitro and in vivo, and have a synergistic effect with conventional chemotherapy drugs against PC. Some SRC inhibitors have been evaluated in clinical trials. This article analyzes the regulatory mechanism of SRC and the recent progress and problems in developing drugs targeting SRC for the treatment of PC. Unfortunately, up to date no SRC inhibitor or regiment containing SRC inhibitors has been approved for the clinical treatment of PC. In the authors' opinion, the introduction of precision medicine principles to carry out SRC inhibitor clinical trials, combination of immunotherapy and SRC inhibitors, seeking more selective and effective SRC inhibitors, and further exploration of the SRC regulatory network may be the future directions for developing SRC-targeted therapies against PC.
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Affiliation(s)
- Zi-Yi Li
- Hepatosplenic Surgery Center, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Xue-Ying Sun
- Hepatosplenic Surgery Center, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
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Dai Y, Siemann D. c-Src is required for hypoxia-induced metastasis-associated functions in prostate cancer cells. Onco Targets Ther 2019; 12:3519-3529. [PMID: 31190858 PMCID: PMC6512571 DOI: 10.2147/ott.s201320] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 03/20/2019] [Indexed: 12/14/2022] Open
Abstract
Background: Metastasis is the major cause of therapeutic failure in prostate cancer patients, and hypoxia has been shown to promote metastatic functions. However, whether Src family kinases (SFKs) can be upregulated under hypoxia is unclear. Materials and methods: In the current study, we evaluated the effects of hypoxia on cellular functions and activities of different SFK members (c-Src, Lyn, Fyn) in prostate cancer cells. Prostate cancer cell functions were determined in vitro including migration (wound-healing assay), invasion (Matrigel-based transwell assay) and clonogenic cell survival (colony formation assay). Protein expression was detected by Western blotting and gene knockdown was accomplished by siRNA transfection. Results:SRC, but not LYN and FYN, is associated with overall survival in prostate cancer patients, while all three phosphorylated proteins are highly expressed in tumors compared to normal tissues. Short-term hypoxic exposure significantly enhances cell migration, invasion, clonogenic survival, and consistently, c-Src phosphorylation in both PC-3ML and C4-2B cells. Knockdown of SRC, but not LYN or FYN, abolished hypoxia-induced functions. Finally, small molecule Src inhibitors strongly inhibited cell behaviors and c-Src activation under hypoxic conditions. Conclusion: Our data show that hypoxia is able to enhance metastatic-associated cell functions by activating c-Src in prostate cancer cells. Importantly, SFK inhibition by small molecule inhibitors was able to impair hypoxia-induced metastasis associated cell functions, suggesting a possible role of SFK inhibitors for prostate cancer treatment.
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Affiliation(s)
- Yao Dai
- Department of Radiation Oncology, University of Florida, Gainesville, FL 32608, USA
| | - Dietmar Siemann
- Department of Radiation Oncology, University of Florida, Gainesville, FL 32608, USA
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Cheng Z, Liu L, Wang Z, Cai Y, Xu Q, Chen P. Hypoxia Activates Src and Promotes Endocytosis Which Decreases MMP-2 Activity and Aggravates Renal Interstitial Fibrosis. Int J Mol Sci 2018; 19:E581. [PMID: 29462885 PMCID: PMC5855803 DOI: 10.3390/ijms19020581] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/22/2018] [Accepted: 02/12/2018] [Indexed: 12/14/2022] Open
Abstract
The aggravation of renal interstitial fibrosis in the advanced-stage of chronic kidney disease is related to decreased matrix metalloproteinase-2 (MMP-2) activity, which is induced by hypoxia in the kidney; however, the specific mechanism remains unclear. We previously demonstrated that inhibition of Caveolin-1, a key gene involved in endocytosis, increased MMP-2 activity in hypoxic HK-2 cells. It has been reported that activated Src (phospho-Src Tyr416) is a key molecule in multiple fibrotic pathways. However, whether Src functions on the regulation of Caveolin-1 and MMP-2 activity in hypoxic HK-2 cells remains poorly understood. To explore the underlying mechanism, a rat model of renal interstitial fibrosis was established, then we observed obvious hypoxia in fibrotic kidney tissue and the protein levels of phospho-Src and Caveolin-1 increased, while MMP-2 activity decreased. Next, we treated HK-2 cells with the phospho-Src inhibitor PP1. Compared with normal cells grown in hypoxia, in cells treated with PP1, the protein levels of phospho-Src and Caveolin-1 decreased, as did the protein levels of the MMP-2-activity-regulated molecules RECK (reversion-inducing-cysteine-rich protein with kazal motifs) and TIMP-2 (tissue inhibitor of metalloproteinase-2), while the protein level of MT1-MMP (membrane type 1-matrix metalloproteinase) increased and MMP-2 activity was enhanced. Therefore, hypoxia promotes the phosphorylation of Src and phospho-Src can enhance the endocytosis of HK-2 cells, which leads to decreased MMP-2 activity and aggravates renal interstitial fibrosis.
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Affiliation(s)
- Zhengyuan Cheng
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
| | - Lei Liu
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
| | - Zhi Wang
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
| | - Yingying Cai
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
| | - Qing Xu
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
| | - Pingsheng Chen
- Department of pathology and pathophysiology, Medical School, Southeast University, Dingjiaqiao 87, Gulou district, Nanjing 210009, China.
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5
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Giovannetti E, van der Borden CL, Frampton AE, Ali A, Firuzi O, Peters GJ. Never let it go: Stopping key mechanisms underlying metastasis to fight pancreatic cancer. Semin Cancer Biol 2017; 44:43-59. [PMID: 28438662 DOI: 10.1016/j.semcancer.2017.04.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/12/2017] [Accepted: 04/18/2017] [Indexed: 02/07/2023]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive neoplasm, predicted to become the second leading cause of cancer-related deaths before 2030. This dismal trend is mainly due to lack of effective treatments against its metastatic behavior. Therefore, a better understanding of the key mechanisms underlying metastasis should provide new opportunities for therapeutic purposes. Genomic analyses revealed that aberrations that fuel PDAC tumorigenesis and progression, such as SMAD4 loss, are also implicated in metastasis. Recently, microRNAs have been shown to play a regulatory role in the metastatic behavior of many tumors, including PDAC. In particular, miR-10 and miR-21 have appeared as master regulators of the metastatic program, while members of the miR-200 family are involved in the epithelial-to-mesenchymal switch, favoring cell migration and invasiveness. Several studies have also found a close relationship between cancer stem cells (CSCs) and biological features of metastasis, and the CSC markers ALDH1, ABCG2 and c-Met are expressed at high levels in metastatic PDAC cells. Emerging evidence reveals that exosomes are involved in the modulation of the tumor microenvironment and can initiate PDAC pre-metastatic niche formation in the liver and lungs. In this review, we provide an overview of the role of all these pivotal factors in the metastatic behavior of PDAC, and discuss their potential exploitation in the clinic to improve current therapeutics and identify new drug targets.
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Affiliation(s)
- E Giovannetti
- Lab Medical Oncology, Dept. Medical Oncology, VU University Medical Center (VUmc), Amsterdam, The Netherlands; Cancer Pharmacology Lab, AIRC Start Up Unit, University of Pisa, Pisa, Italy
| | - C L van der Borden
- Lab Medical Oncology, Dept. Medical Oncology, VU University Medical Center (VUmc), Amsterdam, The Netherlands
| | - A E Frampton
- HPB Surgical Unit, Dept. of Surgery & Cancer, Imperial College, Hammersmith Hospital Campus, London, UK
| | - A Ali
- Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, KP, Pakistan; Institute of Cancer Sciences, University of Glasgow, UK
| | - O Firuzi
- Lab Medical Oncology, Dept. Medical Oncology, VU University Medical Center (VUmc), Amsterdam, The Netherlands; Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - G J Peters
- Lab Medical Oncology, Dept. Medical Oncology, VU University Medical Center (VUmc), Amsterdam, The Netherlands.
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Edgar LJ, Vellanki RN, McKee TD, Hedley D, Wouters BG, Nitz M. Isotopologous Organotellurium Probes Reveal Dynamic Hypoxia In Vivo with Cellular Resolution. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607483] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Landon J. Edgar
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto Ontario M5S 3H6 Canada
| | - Ravi N. Vellanki
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Trevor D. McKee
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - David Hedley
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Bradly G. Wouters
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Mark Nitz
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto Ontario M5S 3H6 Canada
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7
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Edgar LJ, Vellanki RN, McKee TD, Hedley D, Wouters BG, Nitz M. Isotopologous Organotellurium Probes Reveal Dynamic Hypoxia In Vivo with Cellular Resolution. Angew Chem Int Ed Engl 2016; 55:13159-13163. [DOI: 10.1002/anie.201607483] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Landon J. Edgar
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto Ontario M5S 3H6 Canada
| | - Ravi N. Vellanki
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Trevor D. McKee
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - David Hedley
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Bradly G. Wouters
- Departments of Radiation Oncology, Medical Biophysics, and the; STTARR Innovaton Centre; Princess Margaret Cancer Centre; University Health Network; 101 College Street Toronto Ontario M5G 1L7 Canada
| | - Mark Nitz
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto Ontario M5S 3H6 Canada
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Siemann DW, Horsman MR. Modulation of the tumor vasculature and oxygenation to improve therapy. Pharmacol Ther 2015; 153:107-24. [PMID: 26073310 DOI: 10.1016/j.pharmthera.2015.06.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/03/2015] [Indexed: 12/12/2022]
Abstract
The tumor microenvironment is increasingly recognized as a major factor influencing the success of therapeutic treatments and has become a key focus for cancer research. The progressive growth of a tumor results in an inability of normal tissue blood vessels to oxygenate and provide sufficient nutritional support to tumor cells. As a consequence the expanding neoplastic cell population initiates its own vascular network which is both structurally and functionally abnormal. This aberrant vasculature impacts all aspects of the tumor microenvironment including the cells, extracellular matrix, and extracellular molecules which together are essential for the initiation, progression and spread of tumor cells. The physical conditions that arise are imposing and manifold, and include elevated interstitial pressure, localized extracellular acidity, and regions of oxygen and nutrient deprivation. No less important are the functional consequences experienced by the tumor cells residing in such environments: adaptation to hypoxia, cell quiescence, modulation of transporters and critical signaling molecules, immune escape, and enhanced metastatic potential. Together these factors lead to therapeutic barriers that create a significant hindrance to the control of cancers by conventional anticancer therapies. However, the aberrant nature of the tumor microenvironments also offers unique therapeutic opportunities. Particularly interventions that seek to improve tumor physiology and alleviate tumor hypoxia will selectively impair the neoplastic cell populations residing in these environments. Ultimately, by combining such therapeutic strategies with conventional anticancer treatments it may be possible to bring cancer growth, invasion, and metastasis to a halt.
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Affiliation(s)
- Dietmar W Siemann
- Department of Radiation Oncology, University of Florida Health Cancer Center, Gainesville, FL, USA.
| | - Michael R Horsman
- Department of Experimental Clinical Oncology, Aarhus University Hospital-NBG, Aarhus, Denmark
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Ahmadi M, Ahmadihosseini Z, Allison SJ, Begum S, Rockley K, Sadiq M, Chintamaneni S, Lokwani R, Hughes N, Phillips RM. Hypoxia modulates the activity of a series of clinically approved tyrosine kinase inhibitors. Br J Pharmacol 2014; 171:224-36. [PMID: 24117380 DOI: 10.1111/bph.12438] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/23/2013] [Accepted: 09/23/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Hypoxia in tumours is known to cause resistance to conventional chemotherapeutic drugs. In contrast, little is known about the effects of hypoxia on targeted anti-cancer drugs. This study evaluated the effect of hypoxia on a series of clinically approved tyrosine kinase inhibitors (TKIs). EXPERIMENTAL APPROACH The effect of hypoxia (0.1% oxygen) on the activity of conventional cytotoxic drugs (5-fluorouracil, doxorubicin and vinblastine), the hypoxia-activated prodrug tirapazamine and 9 TKIs was determined in a panel of cell lines. Where hypoxia had a marked effect on chemosensitivity, Western blot analysis was conducted to determine the effect of hypoxia on target expression and the effect of TKIs on cell signalling response under aerobic and hypoxic conditions. KEY RESULTS Three patterns of chemosensitivity were observed: resistance under hypoxia, equitoxic activity against hypoxic and aerobic cells, and preferential cytotoxicity to hypoxic cells. Significant hypoxia selectivity (independent of HIF1) was observed in the case of dasatinib and this correlated with the ability of dasatinib to inhibit phosphorylation of Src at tyrosine 530. Sorafenib was significantly less effective under hypoxic conditions but resistance did not correlate with hypoxia-induced changes in Raf/MEK/ERK signalling. CONCLUSIONS AND IMPLICATIONS Hypoxia influences the activity of TKIs but in contrast to conventional cytotoxic drugs, preferential activity against hypoxic cells can occur. The search for hypoxia-targeted therapies has been long and fruitless and this study suggests that some clinically approved TKIs could preferentially target the hypoxic fraction of some tumour types.
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Affiliation(s)
- M Ahmadi
- Institute of Cancer Therapeutics, University of Bradford, Bradford, UK
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Keilhoff G, Lucas B, Pinkernelle J, Steiner M, Fansa H. Effects of cerebrolysin on motor-neuron-like NSC-34 cells. Exp Cell Res 2014; 327:234-55. [PMID: 24997385 DOI: 10.1016/j.yexcr.2014.06.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 06/12/2014] [Accepted: 06/26/2014] [Indexed: 01/01/2023]
Abstract
Although the peripheral nervous system is capable of regeneration, this capability is limited. As a potential means of augmenting nerve regeneration, the effects of cerebrolysin (CL)--a proteolytic peptide fraction--were tested in vitro on the motor-neuron-like NSC-34 cell line and organotypic spinal cord cultures. Therefore, NSC-34 cells were subjected to mechanical stress by changing media and metabolic stress by oxygen glucose deprivation. Afterwards, cell survival/proliferation using MTT and BrdU-labeling (FACS) and neurite sprouting using ImageJ analysis were evaluated. Calpain-1, Src and α-spectrin protein expression were analyzed by Western blot. In organotypic cultures, the effect of CL on motor neuron survival and neurite sprouting was tested by immunohistochemistry. CL had a temporary anti-proliferative but initially neuroprotective effect on OGD-stressed NSC-34 cells. High-dosed or repeatedly applied CL was deleterious for cell survival. CL amplified neurite reconstruction to limited extent, affected calpain-1 protein expression and influenced calpain-mediated spectrin cleavage as a function of Src expression. In organotypic spinal cord slice cultures, CL was not able to support motor neuron survival/neurite sprouting. Moreover, it hampered astroglia and microglia activities. The data suggest that CL may have only isolated positive effects on injured spinal motor neurons. High-dosed or accumulated CL seemed to have adverse effects in treatment of spinal cord injury. Further experiments are required to optimize the conditions for a safe clinical administration of CL in spinal cord injuries.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany.
| | - Benjamin Lucas
- Institute of Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Josephine Pinkernelle
- Institute of Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Michael Steiner
- Institute of Biochemistry and Cell Biology, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Hisham Fansa
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld, Teutoburger Str. 50, D-33604 Bielefeld, Germany
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11
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Rutledge CA, Ng FS, Sulkin MS, Greener ID, Sergeyenko AM, Liu H, Gemel J, Beyer EC, Sovari AA, Efimov IR, Dudley SC. c-Src kinase inhibition reduces arrhythmia inducibility and connexin43 dysregulation after myocardial infarction. J Am Coll Cardiol 2014; 63:928-34. [PMID: 24361364 PMCID: PMC3963804 DOI: 10.1016/j.jacc.2013.10.081] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/20/2013] [Accepted: 10/28/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the role of tyrosine kinase cellular-Src (c-Src) inhibition on connexin43 (Cx43) regulation in a mouse model of myocardial infarction (MI). BACKGROUND MI is associated with decreased expression of Cx43, the principal gap junction protein responsible for propagating current in ventricles. Activated c-Src has been linked to Cx43 dysregulation. METHODS MI was induced in 12-week-old mice by coronary artery occlusion. MI mice were treated with c-Src inhibitors (PP1 or AZD0530), PP3 (an inactive analogue of PP1), or saline. Treated hearts were compared to sham mice by echocardiography, optical mapping, telemetry electrocardiographic monitoring, and inducibility studies. Tissues were collected for immunoblotting, quantitative polymerase chain reaction, and immunohistochemistry. RESULTS Active c-Src was elevated in PP3-treated MI mice compared to sham at the scar border (280%, p = 0.003) and distal ventricle (346%, p = 0.013). PP1 treatment restored active c-Src to sham levels at the scar border (86%, p = 0.95) and distal ventricle (94%, p = 1.0). PP1 raised Cx43 expression by 69% in the scar border (p = 0.048) and by 73% in the distal ventricle (p = 0.043) compared with PP3 mice. PP1-treated mice had restored conduction velocity at the scar border (PP3: 32 cm/s, PP1: 41 cm/s, p < 0.05) and lower arrhythmic inducibility (PP3: 71%, PP1: 35%, p < 0.05) than PP3 mice. PP1 did not change infarct size, electrocardiographic pattern, or cardiac function. AZD0530 treatment demonstrated restoration of Cx43 comparable to PP1. CONCLUSIONS c-Src inhibition improved Cx43 levels and conduction velocity and lowered arrhythmia inducibility after MI, suggesting a new approach for arrhythmia reduction following MI.
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Affiliation(s)
- Cody A Rutledge
- Department of Physiology, University of Illinois at Chicago, Chicago, Illinois; Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island
| | - Fu Siong Ng
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Matthew S Sulkin
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Ian D Greener
- Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island
| | - Artem M Sergeyenko
- Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island
| | - Hong Liu
- Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island
| | - Joanna Gemel
- Department of Pediatrics, University of Chicago, Chicago, Illinois
| | - Eric C Beyer
- Department of Pediatrics, University of Chicago, Chicago, Illinois
| | - Ali A Sovari
- Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island
| | - Igor R Efimov
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Samuel C Dudley
- Lifespan Cardiovascular Institute, the Warren Alpert School of Medicine of Brown University, and the Providence Veterans Administration Medical Center, Providence. Rhode Island.
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13
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Pawlus MR, Hu CJ. Enhanceosomes as integrators of hypoxia inducible factor (HIF) and other transcription factors in the hypoxic transcriptional response. Cell Signal 2013; 25:1895-903. [PMID: 23707522 PMCID: PMC3700616 DOI: 10.1016/j.cellsig.2013.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 05/07/2013] [Indexed: 12/27/2022]
Abstract
Hypoxia is a prevalent attribute of the solid tumor microenvironment that promotes the expression of genes through posttranslational modifications and stabilization of alpha subunits (HIF1α and HIF2α) of hypoxia-inducible factors (HIFs). Despite significant similarities, HIF1 (HIF1α/ARNT) and HIF2 (HIF2α/ARNT) activate common as well as unique target genes and exhibit different functions in cancer biology. More surprisingly, accumulating data indicates that the HIF1- and/or HIF2-mediated hypoxia responses can be oncogenic as well as tumor suppressive. While the role of HIF in the hypoxia response is well established, recent data support the concept that HIF is necessary, but not sufficient for the hypoxic response. Other transcription factors that are activated by hypoxia are also required for the HIF-mediated hypoxia response. HIFs, other transcription factors, co-factors and RNA poll II recruited by HIF and other transcription factors form multifactorial enhanceosome complexes on the promoters of HIF target genes to activate hypoxia inducible genes. Importantly, HIF1 or HIF2 requires distinct partners in activating HIF1 or HIF2 target genes. Because HIF enhanceosome formation is required for the gene activation and distinct functions of HIF1 and HIF2 in tumor biology, disruption of the HIF1 or HIF2 specific enhanceosome complex may prove to be a beneficial strategy in tumor treatment in which tumor growth is specifically dependent upon HIF1 or HIF2 activity.
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Affiliation(s)
- Matthew R. Pawlus
- Molecular Biology Graduate Program University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Cheng-Jun Hu
- Molecular Biology Graduate Program University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Craniofacial Biology University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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Dasatinib Inhibits DNA Repair after Radiotherapy Specifically in pSFK-Expressing Tumor Areas in Head and Neck Xenograft Tumors. Transl Oncol 2013; 6:413-9. [PMID: 23908684 DOI: 10.1593/tlo.13259] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/08/2013] [Accepted: 04/12/2013] [Indexed: 12/12/2022] Open
Abstract
Src family kinases (SFKs) have been implicated in resistance to both radiation and epidermal growth factor receptor (EGFR) inhibition. Therefore, we investigated whether inhibition of SFK through dasatinib (DSB) can enhance the effect of radiotherapy in two in vivo human head and neck squamous cell carcinoma (HNSCC) models. Response to DSB and/or radiotherapy was assessed with tumor growth delay assays in two HNSCC xenograft models, SCCNij153 and SCCNij202. Effects on EGFR signaling were evaluated with Western blot analysis, and effects on DNA repair, hypoxia, and proliferation were investigated with immunohistochemistry. DSB and radiotherapy induced a significant growth delay in both HNSCC xenograft models, although to a lesser extent in SCCNij202. DSB did not inhibit phosphorylated protein kinase B (pAKT) or phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) but did inhibit (phosphorylated) DNA-dependent protein kinase. Moreover, DSB reduced repair of radiation-induced DNA double-strand breaks as shown by an increase of p53-binding protein 1 (53BP1) staining 24 hours after radiation. This effect on DNA repair was only observed in the cell compartment where phosphorylated SFK (pSFK) was expressed: for SCCNij153 tumors in both normoxic and hypoxic areas and for SCCNij202 tumors only in hypoxic areas. No consistent effects of DSB on hypoxia or proliferation were observed. In conclusion, DSB enhances the effect of radiotherapy in vivo by inhibition of radiation-induced DNA repair and is a promising way to improve outcome in HNSCC patients.
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STAT3 and HIF1α cooperatively activate HIF1 target genes in MDA-MB-231 and RCC4 cells. Oncogene 2013; 33:1670-9. [PMID: 23604114 DOI: 10.1038/onc.2013.115] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/19/2013] [Accepted: 02/13/2013] [Indexed: 12/26/2022]
Abstract
Solid tumors often exhibit simultaneously inflammatory and hypoxic microenvironments. The 'signal transducer and activator of transcription-3' (STAT3)-mediated inflammatory response and the hypoxia-inducible factor (HIF)-mediated hypoxia response have been independently shown to promote tumorigenesis through the activation of HIF or STAT3 target genes and to be indicative of a poor prognosis in a variety of tumors. We report here for the first time that STAT3 is involved in the HIF1, but not HIF2-mediated hypoxic transcriptional response. We show that inhibiting STAT3 activity in MDA-MB-231 and RCC4 cells by a STAT3 inhibitor or STAT3 small interfering RNA significantly reduces the levels of HIF1, but not HIF2 target genes in spite of normal levels of hypoxia-inducible transcription factor 1α (HIF1α) and HIF2α protein. Mechanistically, STAT3 activates HIF1 target genes by binding to HIF1 target gene promoters, interacting with HIF1α protein and recruiting coactivators CREB binding protein (CBP) and p300, and RNA polymerase II (Pol II) to form enhanceosome complexes that contain HIF1α, STAT3, CBP, p300 and RNA Pol II on HIF1 target gene promoters. Functionally, the effect of STAT3 knockdown on proliferation, motility and clonogenic survival of tumor cells in vitro is phenocopied by HIF1α knockdown in hypoxic cells, whereas STAT3 knockdown in normoxic cells also reduces cell proliferation, motility and clonogenic survival. This indicates that STAT3 works with HIF1 to activate HIF1 target genes and to drive HIF1-depedent tumorigenesis under hypoxic conditions, but also has HIF-independent activity in normoxic and hypoxic cells. Identifying the role of STAT3 in the hypoxia response provides further data supporting the effectiveness of STAT3 inhibitors in solid tumor treatment owing to their usefulness in inhibiting both the STAT3 and HIF1 pro-tumorigenic signaling pathways in some cancer types.
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16
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Somlo G, Atzori F, Strauss LC, Geese WJ, Specht JM, Gradishar WJ, Rybicki A, Sy O, Vahdat LT, Cortes J. Dasatinib plus capecitabine for advanced breast cancer: safety and efficacy in phase I study CA180004. Clin Cancer Res 2013; 19:1884-93. [PMID: 23403636 DOI: 10.1158/1078-0432.ccr-12-0652] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Dasatinib is an Src family kinase inhibitor with modest activity in advanced breast cancer. We aimed to assess toxicity and maximum tolerated dose (MTD) for dasatinib plus capecitabine, estimate efficacy, and explore effects on angiogenesis. EXPERIMENTAL DESIGN Dose levels (DL) were dasatinib 50 mg twice daily (DL1), 70 mg twice daily (DL2 and DL3), or 100 mg daily (DL3a); plus capecitabine on days 1 to 14 of a 21-day cycle, at 825 mg/m(2) twice daily (DL1 and DL2) or 1,000 mg/m(2) twice daily [DL3 and DL3a (MTD)]. DL3a was expanded to evaluate safety/efficacy. Plasma samples were collected for biomarker analysis. RESULTS Thirty-one and 21 patients were treated in the escalation and expansion phases. Sixty percent of tumors were hormone receptor-positive. Most common adverse events (AE) were any grade nausea (58%), hand-foot syndrome (44%), diarrhea (33%), fatigue (33%), vomiting (31%), and asthenia (31%). Most common grade 3/4 AEs were hand-foot syndrome (12%), diarrhea (8%), fatigue (8%), pleural effusion (8%), and vomiting (6%). The MTD was defined at DL3a (capecitabine 1,000 mg/m(2) twice daily and dasatinib 100 mg daily). Of 25 response-evaluable patients treated at DL3a, confirmed partial response was noted in 24% and stable disease in an additional 32%; median progression-free survival was 14.4 weeks. Significant decreases in plasma VEGF-A and increases in VEGFR-2 and collagen-IV were observed. CONCLUSIONS Dasatinib 100 mg once daily plus capecitabine 1,000 mg/m(2) twice daily were tolerable and were associated with clinical benefit in 56% of response-evaluable patients. Biomarker changes were consistent with an antiangiogenic effect.
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Affiliation(s)
- George Somlo
- City of Hope Comprehensive Cancer Center, Duarte, CA 91010, USA.
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17
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Xi Y, Wei Y, Sennino B, Ulsamer A, Kwan I, Brumwell AN, Tan K, Aghi MK, McDonald DM, Jablons DM, Chapman HA. Identification of pY654-β-catenin as a critical co-factor in hypoxia-inducible factor-1α signaling and tumor responses to hypoxia. Oncogene 2012; 32:5048-57. [PMID: 23246962 DOI: 10.1038/onc.2012.530] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 10/03/2012] [Accepted: 10/14/2012] [Indexed: 12/26/2022]
Abstract
Hypoxia is linked to epithelial-mesenchymal transition (EMT) and tumor progression in numerous carcinomas. Responses to hypoxia are thought to operate via hypoxia-inducible factors (HIFs), but the importance of co-factors that regulate HIF signaling within tumors is not well understood. Here, we elucidate a signaling pathway that physically and functionally couples tyrosine phosphorylation of β-catenin to HIF1α signaling and HIF1α-mediated tumor EMT. Primary human lung adenocarcinomas accumulate pY654-β-catenin and HIF1α. All pY654-β-catenin, and only the tyrosine phosphorylated form, was found complexed with HIF1α and active Src, both within the human tumors and in lung tumor cell lines exposed to hypoxia. Phosphorylation of Y654, generated by hypoxia mediated, reactive oxygen species (ROS)-dependent Src kinase activation, was required for β-catenin to interact with HIF1α and Src, to promote HIF1α transcriptional activity, and for hypoxia-induced EMT. Mice bearing hypoxic pancreatic islet adenomas, generated by treatment with anti-vascular endothelial growth factor antibodies, accumulate HIF1α/pY654-β-catenin complexes and develop an invasive phenotype. Concurrent administration of the ROS inhibitor N-acetylcysteine abrogated β-catenin/HIF pathway activity and restored adenoma architecture. Collectively, the findings implicate accumulation of pY654-β-catenin specifically complexed to HIF1α and Src kinase as critically involved in HIF1α signaling and tumor invasion. The findings also suggest that targeting ROS-dependent aspects of the pY654-β-catenin/ HIF1α pathway may attenuate untoward biological effects of anti-angiogenic agents and tumor hypoxia.
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Affiliation(s)
- Y Xi
- Pulmonary and Critical Care Division, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
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18
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Involvement of Src in the Adaptation of Cancer Cells under Microenvironmental Stresses. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:483796. [PMID: 22988500 PMCID: PMC3439988 DOI: 10.1155/2012/483796] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 05/16/2012] [Accepted: 06/04/2012] [Indexed: 01/03/2023]
Abstract
Protein-tyrosine phosphorylation, which is catalyzed by protein-tyrosine kinase (PTK), plays a pivotal role in a variety of cellular functions related to health and disease. The discovery of the viral oncogene Src (v-Src) and its cellular nontransforming counterpart (c-Src), as the first example of PTK, has opened a window to study the relationship between protein-tyrosine phosphorylation and the biology and medicine of cancer. In this paper, we focus on the roles played by Src and other PTKs in cancer cell-specific behavior, that is, evasion of apoptosis or cell death under stressful extracellular and/or intracellular microenvironments (i.e., hypoxia, anoikis, hypoglycemia, and serum deprivation).
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19
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Sovari AA, Iravanian S, Dolmatova E, Jiao Z, Liu H, Zandieh S, Kumar V, Wang K, Bernstein KE, Bonini MG, Duffy HS, Dudley SC. Inhibition of c-Src tyrosine kinase prevents angiotensin II-mediated connexin-43 remodeling and sudden cardiac death. J Am Coll Cardiol 2012; 58:2332-9. [PMID: 22093512 DOI: 10.1016/j.jacc.2011.07.048] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/26/2011] [Indexed: 01/13/2023]
Abstract
OBJECTIVES The aim of this study was to test whether c-Src tyrosine kinase mediates connexin-43 (Cx43) reduction and sudden cardiac death in a transgenic mouse model of cardiac-restricted overexpression of angiotensin-converting enzyme (ACE8/8 mice). BACKGROUND Renin-angiotensin system activation is associated with an increased risk for arrhythmia and sudden cardiac death, but the mechanism is not well understood. The up-regulation of c-Src by angiotensin II may result in the reduction of Cx43, which impairs gap junction function and provides a substrate for arrhythmia. METHODS Wild-type and ACE8/8 mice with and without treatment with the c-Src inhibitor 1-(1,1-dimethylethyl)-1-(4-methylphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (PP1) were studied. Telemetry monitoring, in vivo electrophysiologic studies, Western blot analyses for total and phosphorylated c-Src and Cx43, immunohistochemistry staining for Cx43, and functional assessment of Cx43 with fluorescent dye diffusion were performed. RESULTS The majority of the arrhythmic deaths resulted from ventricular tachycardia degenerating to ventricular fibrillation (83%). Levels of total and phosphorylated c-Src were increased and Cx43 reduced in ACE8/8 mice. PP1 reduced total and phosphorylated c-Src levels, increased Cx43 level by 2.1-fold (p < 0.005), increased Cx43 at the gap junctions (immunostaining), improved gap junctional communication (dye spread), and reduced ventricular tachycardia inducibility and sudden cardiac death. The survival rate increased from 11% to 86% with 4 weeks of PP1 treatment (p < 0.005). Treatment with an inactive analog did not change survival or Cx43 levels. CONCLUSIONS Renin-angiotensin system activation is associated with c-Src up-regulation, Cx43 loss, reduced myocyte coupling, and arrhythmic sudden death, which can be prevented by c-Src inhibition. This suggests that an increase in c-Src activity may help mediate renin-angiotensin system-induced arrhythmias and that c-Src inhibitors might exert antiarrhythmic activity.
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Affiliation(s)
- Ali A Sovari
- Section of Cardiology and Center for Cardiovascular Research, University of Illinois at Chicago, 840 S.Wood Street, Chicago, IL 60612, USA.
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20
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Jeong EM, Liu M, Sturdy M, Gao G, Varghese ST, Sovari AA, Dudley SC. Metabolic stress, reactive oxygen species, and arrhythmia. J Mol Cell Cardiol 2011; 52:454-63. [PMID: 21978629 DOI: 10.1016/j.yjmcc.2011.09.018] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 08/20/2011] [Accepted: 09/19/2011] [Indexed: 02/07/2023]
Abstract
Cardiac arrhythmias can cause sudden cardiac death (SCD) and add to the current heart failure (HF) health crisis. Nevertheless, the pathological processes underlying arrhythmias are unclear. Arrhythmic conditions are associated with systemic and cardiac oxidative stress caused by reactive oxygen species (ROS). In excitable cardiac cells, ROS regulate both cellular metabolism and ion homeostasis. Increasing evidence suggests that elevated cellular ROS can cause alterations of the cardiac sodium channel (Na(v)1.5), abnormal Ca(2+) handling, changes of mitochondrial function, and gap junction remodeling, leading to arrhythmogenesis. This review summarizes our knowledge of the mechanisms by which ROS may cause arrhythmias and discusses potential therapeutic strategies to prevent arrhythmias by targeting ROS and its consequences. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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Affiliation(s)
- Euy-Myoung Jeong
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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21
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Chang Q, Jurisica I, Do T, Hedley DW. Hypoxia Predicts Aggressive Growth and Spontaneous Metastasis Formation from Orthotopically Grown Primary Xenografts of Human Pancreatic Cancer. Cancer Res 2011; 71:3110-20. [PMID: 21343390 DOI: 10.1158/0008-5472.can-10-4049] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Qing Chang
- Ontario Cancer Institute/Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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22
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Schenone S, Brullo C, Musumeci F, Botta M. Novel dual Src/Abl inhibitors for hematologic and solid malignancies. Expert Opin Investig Drugs 2010; 19:931-45. [PMID: 20557276 DOI: 10.1517/13543784.2010.499898] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD c-Src and Bcr-Abl are two non-receptor or cytoplasmic tyrosine kinases (TKs) that play important roles in the development of solid and hematological malignancies. Indeed, Src is overexpressed or hyperactivated in a variety of solid tumors, while Bcr-Abl is the causative agent of chronic myeloid leukemia (CML), where Src is also involved. The two enzymes share significant sequence homology and remarkable structural resemblance. AREAS COVERED IN THIS REVIEW ATP-competitive compounds originally developed as Src inhibitors, showed to be also potent Abl inhibitors. Dasatinib, the first dual Src/Abl inhibitor approved by the US FDA in 2006 for the treatment of imatinib-resistant CML, is currently being tested in several clinical trials for the treatment of different solid tumors. SKI-606 and AZD0530 are two other important dual Src/Abl inhibitors extensively tested in animal models and in clinical trials, but not entered into therapy yet. WHAT THE READER WILL GAIN In this review we will report the latest results regarding dasatinib, SKI-606 and AZD0530, but also the knowledge on new compounds that have appeared in the literature in the last few years, including AP24163, AP24534, XL228, DC2036. We will focus on the most recent clinical trials or on preclinical studies that are in progress on these small-molecule TK inhibitors that represent a targeted therapy with high potential against cancer. TAKE HOME MESSAGE Molecularly targeted therapies, including the inhibition of specific TKs hyperactivated or overexpressed in many human cancers, could be less toxic than the classical non-specific cytotoxic chemotherapeutic agents; they could offer important therapeutic effects, especially if used in association with other agents such as monoclonal antibodies.
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Affiliation(s)
- Silvia Schenone
- University of Genoa, Dipartimento di Scienze Farmaceutiche, Viale Benedetto VX, Genoa, Italy.
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23
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Zeng M, Kikuchi H, Pino MS, Chung DC. Hypoxia activates the K-ras proto-oncogene to stimulate angiogenesis and inhibit apoptosis in colon cancer cells. PLoS One 2010; 5:e10966. [PMID: 20532039 PMCID: PMC2881039 DOI: 10.1371/journal.pone.0010966] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 05/12/2010] [Indexed: 12/22/2022] Open
Abstract
The KRAS proto-oncogene plays a key role in the development of many human tumors and is commonly activated by somatic mutation or signaling through specific growth factor receptors. However, the interaction between the micro-environment and K-ras activity has not been defined. Hypoxia invariably develops as tumors outgrow their supply of oxygen. A series of well-orchestrated cellular adaptations occur that stimulate angiogenesis and enhance survival of the tumor in hypoxic conditions. Our previous studies demonstrated that mutant KRAS alleles can interact with hypoxia to induce vascular endothelial growth factor (VEGF) in colon cancer. We sought to determine whether similar hypoxic responses are also present in tumors without a KRAS mutation. Hypoxia consistently increased the levels of activated, GTP-bound K-ras in colon cancer cell lines with a wild-type KRAS gene, and this depended upon the activation of c-Src. Inhibition of c-Src by PP2 treatment or siRNA knockdown blocked the hypoxic activation of K-ras. This activation of K-ras did not depend upon EGFR and resulted in the phosphorylation of Akt and induction of VEGF expression. In addition, activation of K-ras significantly blocked apoptosis in hypoxic conditions. These studies reveal a unique adaptive mechanism in hypoxia that activates K-ras signaling in the absence of a mutant KRAS oncogene.
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Affiliation(s)
- Min Zeng
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hirotoshi Kikuchi
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Maria S. Pino
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Daniel C. Chung
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: .
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24
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Mujcic H, Rzymski T, Rouschop KMA, Koritzinsky M, Milani M, Harris AL, Wouters BG. Hypoxic activation of the unfolded protein response (UPR) induces expression of the metastasis-associated gene LAMP3. Radiother Oncol 2009; 92:450-9. [PMID: 19726095 DOI: 10.1016/j.radonc.2009.08.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/12/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND AND PURPOSE Tumour hypoxia contributes to failure of cancer treatment through its ability to protect against therapy and adversely influence tumour biology. In particular, several studies suggest that hypoxia promotes metastasis. Hypoxia-induced cellular changes are mediated by oxygen-sensitive signaling pathways that activate downstream transcription factors. We have investigated the induction and transcriptional regulation of a novel metastasis-associated gene, LAMP3 during hypoxia. MATERIALS AND METHODS Microarray, quantitative PCR, Western blot analysis and immunohistochemistry were used to investigate hypoxic regulation of LAMP3. The mechanism for LAMP3 induction was investigated using transient RNAi and stable shRNA targeting components of the hypoxic response. Endoplasmic reticulum stress inducing agents, including proteasome inhibitors were assessed for their ability to regulate LAMP3. RESULTS LAMP3 is strongly induced by hypoxia at both the mRNA and protein levels in a large panel of human tumour cell lines. Induction of LAMP3 occurs as a consequence of the activation of the PERK/eIF2alpha/ATF4 arm of the unfolded protein response (UPR) and is independent of HIF-1alpha. LAMP3 is expressed heterogeneously within the microenvironment of tumours, overexpressed in breast cancer, and increases in tumours treated with avastin. CONCLUSIONS These data identify LAMP3 as a novel hypoxia-inducible gene regulated by the UPR. LAMP3 is a new candidate biomarker of UPR activation by hypoxia in tumours and is a potential mediator of hypoxia-induced metastasis.
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Affiliation(s)
- Hilda Mujcic
- Maastricht Radiation Oncology (MaastRO) Lab, Maastricht University, The Netherlands
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25
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Abstract
The successful growth of a metastasis, by definition, requires the presence of at least 1 cancer stem cell. Metastasis is a complex process, and an important contributor to this process is the influence of the tissue microenvironment, both cell-cell and cell-matrix interactions and the pathophysiologic conditions in tumors, such as hypoxia. A number of studies have suggested that normal stem cells may reside in "niches," where cell-cell and cell-matrix interactions can provide critical signals to support and maintain the undifferentiated phenotype of the stem cells. In this article, the evidence that these niches may be hypoxic is described, and the potential role that hypoxia may play in maintaining the stem cell phenotype in cancers is discussed. Recent work has suggested that there may be a linkage between the stem cell phenotype and that induced by the process of epithelial-mesenchymal transition (EMT). EMT plays an important role in cell movement and organ formation during embryogenesis, and it is currently hypothesized to be a major mechanism by which epithelial cancers may generate cells that can form metastases. Recent evidence suggests that the expression of certain genes involved in EMT is influenced by low oxygen levels, again suggesting a linkage between stem cells and hypoxia. Whether this supposition is correct remains an open question that will only be answered by further experimentation, but the potential role of hypoxia is critical because of its widespread existence in tumors and its known role in resistance to both radiation and drug treatment.
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Affiliation(s)
- Richard P Hill
- Division of Applied Molecular Oncology, Ontario Cancer Institute/Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.
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