Mechanisms of disease: Insights into the emerging role of signal transducers and activators of transcription in cancer.
ABSTRACT Members of the signal transducers and activators of transcription (STAT) pathway, which were originally identified as key components linking cytokine signals to transcriptional events in cells, have recently been demonstrated to have a major role in cancer. They are cytoplasmic proteins that form functional dimers with each other when activated by tyrosine phosphorylation. Activated STAT proteins translocate to the nucleus to regulate expression of genes by binding to specific elements within gene promoters. Constitutive activation of the STAT family members Stat3 and Stat5, and/or loss of Stat1 signaling, is found in a large group of diverse tumors. Increasing evidence demonstrates that STAT proteins can regulate many pathways important in oncogenesis including cell-cycle progression, apoptosis, tumor angiogenesis, tumor-cell invasion and metastasis, and tumor-cell evasion of the immune system. Based on these findings, a growing effort is underway to target STAT proteins directly and indirectly for cancer therapy. This review will highlight STAT signaling pathways, STAT target genes involved in cancer, evidence for STAT activation in human cancers, and therapeutic strategies to target STAT molecules for anticancer therapy.
- SourceAvailable from: Alireza Rafiei[Show abstract] [Hide abstract]
ABSTRACT: Inflammatory condition is the consequence of defensive mechanism of immune system against viral and bacterial infection, tissue injury, UV radiation, stress and etc. Persistently acute inflammation leads to chronic phase which is characterized by production of pro-inflammatory mediators from T cells. These molecules (e.g. IL-6, TNF-α, IL-1β and IL-17) are mostly pleiotropic cytokines involved in multiple signaling cascades. NF-κB, STAT3, and HIF-1α are the major engaged pathways directing to several downstream targets associating with tumorigenesis and inflammation. Carcinogenesis processes such as DNA mutation/damage, proliferation, angiogenesis, apoptosis, and invasion are implicated to inflammation. Clearly there is a closely association between cancer and inflammation reported as “Seven Hallmark of Cancer”. The elucidation of relationship between inflammation and cancer and their interaction may result in effective therapy and prevention. Gastric cancer is one of the main cancer involved in complex correlation of inflammation and cancer. Inflammation in gastric epithelium could trigger cellular transformation and promote invasion by inducing immune responses and utilizing signaling cascades. Gastric tumor microenvironment has inverse association by providing cytokines and inflammatory mediators. This closely relationship facilitates gastric tumor development and the induction of chronic inflammation in tumor microenvironment. The current review will focus on describing the possible and critical ways in which inflammation and cancer are linked together with specific view to gastric cancer and inflammation. Finally, it introduces some putative treatment generally used in this way in order to direct more attention for further exploration.Res Mol Med. 2014; 2 (2). 06/2014; 2(2):1-15.
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ABSTRACT: Hepatocellular carcinoma is the fifth most common tumor and the third cause of death for cancer in the world. Among the main causative agents of this tumor is the chronic infection by hepatitis viruses B and C, which establish a context of chronic inflammation degenerating in fibrosis, cirrhosis, and, finally, cancer. Recent findings, however, indicate that hepatitis viruses are not only responsible for cancer onset but also for its progression towards metastasis. Indeed, they are able to promote epithelial-mesenchymal transition, a process of cellular reprogramming underlying tumor spread. In this manuscript, we review the currently known molecular mechanisms by which hepatitis viruses induce epithelial-mesenchymal transition and, thus, hepatocellular carcinoma progression.Tumor Biology 05/2014; · 2.52 Impact Factor
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ABSTRACT: Although interleukin-9 (IL-9) exhibits pleiotropic functions in the immune system, it remains a well-known cytokine in hematological malignancies. Previous cell culture and animal model studies have revealed that the Janus kinase-signal transducer and activator of transcription signaling pathway, which may be activated by a number of cytokines including IL-9, is critical in hematological malignancies. The current review summarizes the characterization of the biological activities of IL-9, highlights the clearly defined roles of the cytokine, and outlines questions with regard to the functions of IL-9 that require further exploration and their downstream signaling proteins, signal transducers and activators of transcription.Oncology letters 03/2014; 7(3):602-610. · 0.24 Impact Factor