Chapters authored
JAK, an Oncokinase in Hematological Cancer
Janus kinases (JAKs) play an essential role in the regulation of cytokine signaling. They control cell survival, proliferation, differentiation, immune response, and hematopoiesis. Deregulation of JAK signaling has been associated to the pathogenesis of numerous immune-inflammatory diseases, hematological malignancies, and solid tumors. Thus, JAK proteins have emerged as attractive therapeutic targets in the last decade. The discovery of the gain-of-function JAK2 mutation (JAK2 V617F) as the main cause of polycythemia vera—a chronic myeloproliferative syndrome—led to the development of the JAK inhibitor ruxolitinib. This key finding opened the door to the search for new therapeutic agents able to suppress the constitutive activation of JAK signaling in hematological cancers and other tumors. However, given the conserved nature of the kinase domain among JAK family members, and the interrelated roles of JAK kinases in many physiological processes, including hematopoiesis and immunity, the broad usage of JAK inhibitors in hematology is challenged by their narrow therapeutic window. Novel therapies are, therefore, needed. This chapter focuses on the understanding of the complex signaling of JAK proteins in cancerous cells, the various JAK aberrations implicated in myeloproliferative neoplasms, leukemia, and lymphoma, and the clinically available JAK inhibitors in cancer therapy.
Part of the book: Tyrosine Kinases as Druggable Targets in Cancer
Control of Liver Gene Expression by Sex Steroids and Growth Hormone Interplay
Sex steroids have important physiological actions, which are not limited to reproductive organs, in both females and males. They exert important physiological roles, including the regulation of somatotropic-liver axis, intermediate metabolism, or gender dimorphism. This is in part because the liver is a sex steroid-responsive organ where sex steroid- and growth hormone (GH)-dependent signaling pathways connect to regulate complex gene expression networks. Sex steroids can impact liver gene expression by a direct, through hepatic estrogen receptor (ER)α and androgen receptor (AR), or indirect mechanisms, by modulation of pituitary GH secretion and/or interaction with the GHR-STAT5b signaling pathway. Therefore, deficiency of sex steroid- and GH-dependent signaling pathways might cause a dramatic impact on mammalian liver physiology. In this chapter, we will focus our attention on main concepts and paradigms involved in the role and interplay between sex steroid- and GH-dependent signaling to regulate gene expression networks in the mammalian liver. A better understanding of how sex steroids and interactions with GH-STAT5b signaling pathway influence physiological and pathological states in the liver will contribute to improve clinical management of patients with disorders in body growth, development, and metabolism.
Part of the book: Chemistry and Biological Activity of Steroids