The T-cell leukemia associated ribosomal RPL10 R98S mutation enhances JAK-STAT signaling. (original) (raw)

JAK/STAT Signaling: Molecular Targets, Therapeutic Opportunities, and Limitations of Targeted Inhibitions in Solid Malignancies

Frontiers in Pharmacology

JAK/STAT signaling pathway is one of the important regulatory signaling cascades for the myriad of cellular processes initiated by various types of ligands such as growth factors, hormones, and cytokines. The physiological processes regulated by JAK/STAT signaling are immune regulation, cell proliferation, cell survival, apoptosis and hematopoiesis of myeloid and non-myeloid cells. Dysregulation of JAK/STAT signaling is reported in various immunological disorders, hematological and other solid malignancies through various oncogenic activation mutations in receptors, downstream mediators, and associated transcriptional factors such as STATs. STATs typically have a dual role when explored in the context of cancer. While several members of the STAT family are involved in malignancies, however, a few members which include STAT3 and STAT5 are linked to tumor initiation and progression. Other STAT members such as STAT1 and STAT2 are pivotal for antitumor defense and maintenance of an effe...

Dysregulation of JAK-STAT pathway in hematological malignancies and JAK inhibitors for clinical application

Biomarker Research, 2013

JAK-STAT (Janus associated kinase-signal transducer and activator of transcription) pathway plays a critical role in transduction of extracellular signals from cytokines and growth factors involved in hematopoiesis, immune regulation, fertility, lactation, growth and embryogenesis. JAK family contains four cytoplasmic tyrosine kinases, JAK1-3 and Tyk2. Seven STAT proteins have been identified in human cells, STAT1-6, including STAT5a and STAT5b.

JAK-STAT signaling in cancer: From cytokines to non-coding genome

Cytokine, 2016

In the past decades, studies of the Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) signaling have uncovered highly conserved programs linking cytokine signaling to the regulation of essential cellular mechanisms such as proliferation, invasion, survival, inflammation and immunity. Inhibitors of the JAK/STAT pathway are used for treatment of autoimmune diseases, such as rheumatoid arthritis or psoriasis. Aberrant JAK/STAT signaling has been identified to contribute to cancer progression and metastatic development. Targeting of JAK/STAT pathway is currently one of the most promising therapeutic strategies in prostate cancer (PCa), hematopoietic malignancies and sarcomas. Notably, newly identified regulators of JAK/ STAT signaling, the non-coding RNAs transcripts and their role as important targets and potential clinical biomarkers are highlighted in this review. In addition to the established role of the JAK/ STAT signaling pathway in traditional cytokine signaling the non-coding RNAs add yet another layer of hidden regulation and function.

Jak/Stat as a Novel Target for Treatment of Leukemia

2014

Several advances in recent year have focused on leukemia treatment. Primary treatments available for leukemia are Radiotherapy, Bone marrow transplant, Biotherapy, Surgery and Chemotherapy. BCR-ABL tyrosine kinase inhibitor E.g. Imatinib mesylate has revolutionized and set the landmark in this field. It is used as first line treatment in chronic myelogenous leukemia. But, due to resistance developed by the blood cells through the mutations in the BCR-ABL gene need for the newer target arises. The Janus kinase (JAK) and signal transduction and activator of transcription (STAT) pathway stands in a paradigm of how diverse extracellular signal can elicit rapid changes in gene expression in specific target. JAK/STAT is dominant pathway for signal transduction of erythropoietin, growth factor and cytokines receptors. Cytokines are major mediators for cell maturation and multiplication. When cytokines bound to the receptor Jaks gets autophosphorylates and in turn, phosphorylates STATs. Act...

Proliferation of Adult T Cell Leukemia/Lymphoma Cells is Associated with the Constitutive Activation of JAK/STAT Proteins

Proceedings of The National Academy of Sciences, 1997

Here we tested the status of JAK͞STAT phosphorylation and DNA-binding activity of STAT proteins in cell extracts of uncultured leukemic cells from 12 patients with ATLL by either DNA-binding assays, using DNA oligonucleotides specific for STAT-1 and STAT-3, STAT-5 and STAT-6 or, more directly, by immunoprecipitation and immunoblotting with anti-phosphotyrosine antibody for JAK and STAT proteins. Leukemic cells from 8 of 12 patients studied displayed constitutive DNA-binding activity of one or more STAT proteins, and the constitutive activation of the JAK͞STAT pathway was found to persist over time in the 2 patients followed longitudinally. Furthermore, an association between JAK3 and STAT-1, STAT-3, and STAT-5 activation and cell-cycle progression was demonstrated by both propidium iodide staining and bromodeoxyuridine incorporation in cells of four patients tested. These results imply that JAK͞STAT activation is associated with replication of leukemic cells and that therapeutic approaches aimed at JAK͞STAT inhibition may be considered to halt neoplastic growth.

Targeting the JAK/STAT pathway in solid tumors

Journal of Cancer Metastasis and Treatment, 2020

Aberrant activation of signal transducer and activator of transcription (STAT) proteins is associated with the development and progression of solid tumors. However, as transcription factors, these proteins are difficult to target directly. In this review, we summarize the role of targeting Janus kinases (JAKs), upstream activators of STATs, as a strategy for decreasing STAT activation in solid tumors. Preclinical studies in solid tumor cell line models show that JAK inhibitors decrease STAT activation, cell proliferation, and cell survival; in in vivo models,

Therapeutic Targeting of the JAK/STAT Pathway

Basic & Clinical Pharmacology & Toxicology, 2014

Antibodies that block cytokine function provide a powerful therapeutic tool especially for the treatment of autoimmune diseases. Cytokines are a group of small hydrophilic glycoproteins that bind their receptors on the cell surface and subsequently activate intracellular signalling cascades, such as the JAK/STAT pathway. A bulk of evidence has demonstrated that genetic mutations in signalling molecules can cause immunodeficiencies and malignant cell growth. As a result, several drug companies have begun to develop therapeutics that inhibit the function of JAK tyrosine kinases. Currently, two JAK inhibitors, tofacitinib and ruxolitinib, are used in the clinic for treating rheumatoid arthritis and myeloproliferative diseases, respectively. Inhibiting JAK function has been shown to efficiently prevent the uncontrolled growth of cancerous cells and to harness overly active immune cells. In the future, other small molecule compounds are likely to come into clinical use, and intense work is ongoing to develop inhibitors that specifically target the constitutively active mutant JAKs. This MiniReview will summarize the basic features of the JAK/STAT pathway, its role in human disease and the therapeutic potential of JAK/STAT inhibitors.

Distinct Clinical Phenotypes Associated with JAK2V617F Reflect Differential STAT1 Signaling

Cancer Cell, 2010

The JAK2V617F mutation is associated with distinct myeloproliferative neoplasms, including polycythemia vera (PV) and essential thrombocythemia (ET), but it remains unclear how it generates disparate disorders. By comparing clonally-derived mutant and wild-type cells from individual patients, we demonstrate that the transcriptional consequences of JAK2V617F are subtle, and that JAK2V617F-heterozygous erythroid cells from ET and PV patients exhibit differential interferon signaling and STAT1 phosphorylation. Increased STAT1 activity in normal CD34-positive progenitors produces an ET-like phenotype, whereas downregulation of STAT1 activity in JAK2V617F-heterozygous ET progenitors produces a PV-like phenotype. Our results illustrate the power of clonal analysis, indicate that the consequences of JAK2V617F reflect a balance between STAT5 and STAT1 activation and are relevant for other neoplasms associated with signaling pathway mutations.

“Do We Know Jack” About JAK? A Closer Look at JAK/STAT Signaling Pathway

Frontiers in Oncology, 2018

Janus tyrosine kinase (JAK) family of proteins have been identified as crucial proteins in signal transduction initiated by a wide range of membrane receptors. Among the proteins in this family JAK2 has been associated with important downstream proteins, including signal transducers and activators of transcription (STATs), which in turn regulate the expression of a variety of proteins involved in induction or prevention of apoptosis. Therefore, the JAK/STAT signaling axis plays a major role in the proliferation and survival of different cancer cells, and may even be involved in resistance mechanisms against molecularly targeted drugs. Despite extensive research focused on the protein structure and mechanisms of activation of JAKs, and signal transduction through these proteins, their importance in cancer initiation and progression seem to be underestimated. This manuscript is an attempt to highlight the role of JAK proteins in cancer biology, the most recent developments in targeting JAKs, and the central role they play in intracellular cross-talks with other signaling cascades.