Introduction: The Hedgehog (HH) pathway constitutes a collection of signaling molecules which critically influence embryogenesis. In adults, however, the HH pathway remains integral to the proliferation, maintenance, and apoptosis of adult stem cells including hematopoietic stem cells.
Areas covered: We discuss the current understanding of the HH pathway as it relates to normal hematopoiesis, the pathology of acute myeloid leukemia (AML), the rationale for and data from combination therapies including HH pathway inhibitors, and ultimately the prospects that might offer promise in targeting this pathway in AML.
Expert opinion: Efforts to target the HH pathway have been focused on impeding this disposition and restoring chemosensitivity to conventional myeloid neoplasm therapies. The year 2018 saw the first approval of a HH pathway inhibitor (glasdegib) for AML, though for an older population and in combination with an uncommonly-used therapy. Several other clinical trials with agents targeting modulators of HH signaling in AML and MDS are underway. Further study and understanding of the interplay between the numerous aspects of HH signaling and how it relates to the augmented survival of AML will provide a more reliable substrate for therapeutic strategies in patients with this poor-risk disease. 相似文献
Introduction: Cancer treatment is moving away from conventional cytotoxic drugs and towards agents that target specific proteins and mechanisms important to cancer development or survival. The Hedgehog Pathway (HhP) is a signal transduction pathway and its constitutive activation is tumorigenic in basal cell carcinoma (BCC). The HhP enables phenotypic flexibility, and channels tumor-stroma interactions. As a result, it is over-expressed in numerous cancers as well as in the tumor microenvironment and may represent a promising therapeutic target.Areas covered: In this article, we review the rationale for targeting HhP and its role as an oncogenic driver, in tumor epithelial-to-mesenchymal transition (EMT), and in the tumor microenvironment and describe the results of preclinical and clinical studies involving HhP inhibitors.Expert opinion: HhP activation plays an important role in both the tumor microenvironment and tumor EMT which can lead to treatment resistance for a number of different malignancies. In addition to standard use in BCC, several HhP inhibitors are in preclinical, early, and mid-stage clinical development for other solid and hematologic malignancies. 相似文献
Increased expression of GLI1, the main Hedgehog signalling pathway effector, is related to unfavourable prognosis and progressive disease of certain breast cancer subtypes. We used conditional transgenic mice induced to overexpress GLI1 in the mammary epithelium either alone or in combination with deletion of one Trp53 allele to address the role of elevated GLI1 expression in breast tumour initiation and progression. Induced GLI1 expression facilitates mammary gland tumour formation and this was further increased upon heterozygous deletion of Trp53. The GLI1-induced primary tumours were of different murine molecular subtypes, including Normal-likeEx, Class8Ex, Claudin-LowEx and Erbb2-likeEx. The gene expression profiles of some of the tumours correlated well with the PAM50 subtypes for human breast cancer. Whole-exome sequencing revealed somatic mutation profiles with only little overlap between the primary tumours. Orthotopically serially transplanted GLI1-induced tumours maintained the main morphological characteristics of the primary tumours for ≥10 generations. Independent of Trp53 status and molecular subtype, the serially transplanted GLI1-induced tumours were able to grow both in the absence of transgenic GLI1 expression and in the presence of the GLI1 inhibitor GANT61. These data suggest that elevated GLI1 expression has a determinant role in tumour initiation; however, additional genetic events are required for tumour progression. 相似文献
Holoprosencephaly (HPE), a common developmental defect affecting the forebrain and face, is etiologically heterogeneous and exhibits wide phenotypic variation. Graded degrees of severity of the brain malformation are also reflected in the highly variable craniofacial malformations associated with HPE. In addition, individuals with microforms of HPE, who usually have normal cognition and normal brain imaging, are at risk for having children with HPE. Some obligate carriers for HPE may not have any phenotypic abnormalities. Recurrent chromosomal rearrangements in individuals with HPE suggest loci containing genes important for brain development, and abnormalities in these genes may result in HPE. Recently, Sonic Hedgehog (SHH) was the first gene identified as causing HPE in humans. Proper function of SHH depends on cholesterol modification. Other candidate genes that may be involved in HPE include components of the SHH pathway, elements involved in cholesterol metabolism, and genes expressed in the developing forebrain. 相似文献
Introduction: Basal cell carcinoma (BCC) is the most frequent cancer with increasing incidence over the last decades. Standard of care is surgical excision, upon which complete tumour clearance is achieved in most cases. However, a small subgroup of patients will have remnants of disease post-excision and require further treatment options. Over 90% of all BCCs carry a mutation in PTCH 1 or SMO, two conducting proteins of the Hedgehog pathway (Hh). Therefore, inhibition of the Hh pathway is a promising option for systemic first-line therapy. Vismodegib was the first developed of these small molecules, which was approved by the FDA in January 2012. Areas covered: The authors review current treatment modalities for BCC and discuss current developments in pharmacological therapy. The current literature including meta-analyses, the Cochrane database and registered as well as completed randomized controlled trials. Expert opinion: Hh inhibitors are a new promising treatment option for patients with advanced or metastatic BCC. Phase I and II clinical trials with the Hh inhibitor, vismodegib, showed a significant reduction in tumour size and appearance of new tumours with relatively good tolerability. Nevertheless, further investigation on new molecules and the effectiveness of an intermittent dosing regimen is necessary. 相似文献
Elucidation of signaling pathways that control oligodendrocyte (OL) development is a prerequisite for developing novel strategies for myelin repair in neurological diseases. Despite the extensive work outlining the importance of Hedgehog (Hh) signaling in the commitment and generation of OL progenitor cells (OPCs), there are conflicting reports on the role of Hh signaling in regulating OL differentiation and maturation. In the present study, we systematically investigated OPC specification and differentiation in genetically modified mouse models of Smoothened (Smo), an essential component of the Hh signaling pathway in vertebrates. Through conditional gain-of-function strategy, we demonstrated that hyperactivation of Smo in neural progenitors induced transient ectopic OPC generation and precocious OL differentiation accompanied by the co-induction of Olig2 and Nkx2.2. After the commitment of OL lineage, Smo activity is not required for OL differentiation, and sustained expression of Smo in OPCs stimulated cell proliferation but inhibited terminal differentiation. These findings have uncovered the stage-specific regulation of OL development by Smo-mediated Hh signaling, providing novel insights into the molecular regulation of OL differentiation and myelin repair. 相似文献