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Siveen KS, Sikka S, Surana R, Dai X, Zhang J, Kumar AP, Tan BKH, Sethi G, Bishayee A. Targeting the STAT3 signaling pathway in cancer: role of synthetic and natural inhibitors. Biochim Biophys Acta Rev Cancer 2014; 1845:136-54. [PMID: 24388873 DOI: 10.1016/j.bbcan.2013.12.005] [Citation(s) in RCA: 354] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 12/24/2013] [Accepted: 12/27/2013] [Indexed: 12/25/2022]
Abstract
Signal transducers and activators of transcription (STATs) comprise a family of cytoplasmic transcription factors that mediate intracellular signaling that is usually generated at cell surface receptors and thereby transmit it to the nucleus. Numerous studies have demonstrated constitutive activation of STAT3 in a wide variety of human tumors, including hematological malignancies (leukemias, lymphomas, and multiple myeloma) as well as diverse solid tumors (such as head and neck, breast, lung, gastric, hepatocellular, colorectal and prostate cancers). There is strong evidence to suggest that aberrant STAT3 signaling promotes initiation and progression of human cancers by either inhibiting apoptosis or inducing cell proliferation, angiogenesis, invasion, and metastasis. Suppression of STAT3 activation results in the induction of apoptosis in tumor cells, and accordingly its pharmacological modulation by tyrosine kinase inhibitors, antisense oligonucleotides, decoy nucleotides, dominant negative proteins, RNA interference and chemopreventive agents have been employed to suppress the proliferation of various human cancer cells in culture and tumorigenicity in vivo. However, the identification and development of novel drugs that can target deregulated STAT3 activation effectively remains an important scientific and clinical challenge. This review presents the evidence for critical roles of STAT3 in oncogenesis and discusses the potential for development of novel cancer therapies based on mechanistic understanding of STAT3 signaling cascade.
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Affiliation(s)
| | - Sakshi Sikka
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore
| | - Rohit Surana
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore
| | - Xiaoyun Dai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jingwen Zhang
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Alan Prem Kumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore; School of Biomedical Sciences, Faculty of Health Sciences, Curtin University, Western Australia, Australia; Department of Biological Sciences, University of North Texas, Denton, TX, USA
| | - Benny K H Tan
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Cancer Science Institute of Singapore, National University of Singapore, Centre for Translational Medicine, Singapore.
| | - Anupam Bishayee
- Department of Pharmaceutical Sciences, School of Pharmacy, American University of Health Sciences, Signal Hill, CA, USA.
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The complex function of hsp70 in metastatic cancer. Cancers (Basel) 2013; 6:42-66. [PMID: 24362507 PMCID: PMC3980608 DOI: 10.3390/cancers6010042] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/05/2013] [Accepted: 12/11/2013] [Indexed: 12/26/2022] Open
Abstract
Elevated expression of the inducible heat shock protein 70 (Hsp70) is known to correlate with poor prognosis in many cancers. Hsp70 confers survival advantage as well as resistance to chemotherapeutic agents, and promotes tumor cell invasion. At the same time, tumor-derived extracellular Hsp70 has been recognized as a "chaperokine", activating antitumor immunity. In this review we discuss localization dependent functions of Hsp70 in the context of invasive cancer. Understanding the molecular principles of metastasis formation steps, as well as interactions of the tumor cells with the microenvironment and the immune system is essential for fighting metastatic cancer. Although Hsp70 has been implicated in different steps of the metastatic process, the exact mechanisms of its action remain to be explored. Known and potential functions of Hsp70 in controlling or modulating of invasion and metastasis are discussed.
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