The hedgehog pathway regulates cancer stem cells in serous adenocarcinoma of the ovary (original) (raw)
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Clinical and Experimental Medicine, 2012
The hedgehog (Hh) signaling pathway has been shown to be activated in the cancer stem cells of several tumor entities. The Hh inhibitor GDC-0449 has been proven to be effective in some cancers but not yet in lung cancer. We aimed at investigating whether GDC-0449 is effective in the lung cancer cell lines HCC (adenocarcinoma) and H1339 (small-cell-lung carcinoma), whether in these cell lines stem cell-like side populations (SPs) can be identified, and whether possible effects of GDC-0449 are mediated via SPs. SPs were identified by spectrum shift and decreased fluorescence after staining with 2.5 lg/ml Hoechst 33342. Expression of proteins was quantified by immunofluorescence. GDC-0449 (25 and 50 lM) inhibited concentration-dependent cell growth in HCC and H1339 cells. Further, the inhibitory effects of cisplatin on cell growth were augmented. In HCC and H1339 cell lines, SPs of 0.57 and 0.46% could be identified, respectively. SP, but not non-SP, cells were able to repopulate the original tumor population. The Hh receptor smoothened was detectable in SP but not in non-SP cells, showing the activation of the Hh pathway only in SPs. GDC-0449 considerably reduced SPs in HCC and H1339 cells. We demonstrate for the first time that GDC-0449 effectively reduces cell growth in lung cancer cell lines. This effect is mediated by the inhibition of stem cell-like SPs.
Hedgehog Signaling in the Maintenance of Cancer Stem Cells
Cancers
Cancer stem cells (CSCs) represent a rare population of cells with the capacity to self-renew and give rise to heterogeneous cell lineages within a tumour. Whilst the mechanisms underlying the regulation of CSCs are poorly defined, key developmental signaling pathways required for normal stem and progenitor functions have been strongly implicated. Hedgehog (Hh) signaling is an evolutionarily-conserved pathway essential for self-renewal and cell fate determination. Aberrant Hh signaling is associated with the development and progression of various types of cancer and is implicated in multiple aspects of tumourigenesis, including the maintenance of CSCs. Here, we discuss the mounting evidence suggestive of Hh-driven CSCs in the context of haematological malignancies and solid tumours and the novel strategies that hold the potential to block many aspects of the transformation attributed to the CSC phenotype, including chemotherapeutic resistance, relapse and metastasis.
Review: Targeting the Hedgehog pathway in cancer
Therapeutic Advances in Medical Oncology, 2010
The Hedgehog (Hh) pathway is a major regulator of many fundamental processes in vertebrate embryonic development including stem cell maintenance, cell differentiation, tissue polarity and cell proliferation. Constitutive activation of the Hh pathway leading to tumorigenesis is seen in basal cell carcinomas and medulloblastoma. A variety of other human cancers, including brain, gastrointestinal, lung, breast and prostate cancers, also demonstrate inappropriate activation of this pathway. Paracrine Hh signaling from the tumor to the surrounding stroma was recently shown to promote tumorigenesis. This pathway has also been shown to regulate proliferation of cancer stem cells and to increase tumor invasiveness. Targeted inhibition of Hh signaling may be effective in the treatment and prevention of many types of human cancers. The discovery and synthesis of specific Hh pathway inhibitors have significant clinical implications in novel cancer therapeutics. Several synthetic Hh antagonists are now available, several of which are undergoing clinical evaluation. The orally available compound, GDC-0449, is the farthest along in clinical development. Initial clinical trials in basal cell carcinoma and treatment of select patients with medulloblastoma have shown good efficacy and safety. We review the molecular basis of Hh signaling, the current understanding of pathway activation in different types of human cancers and we discuss the clinical development of Hh pathway inhibitors in human cancer therapy.
The Role of Hedgehog Signaling Pathway in Head and Neck Squamous Cell Carcinoma
Cells
Head and neck squamous cell carcinoma (HNSCC) is the sixth leading malignancy worldwide, with a poor prognosis and limited treatment options. Molecularly targeted therapies for HNSCC are still lacking. However, recent reports provide novel insights about many molecular alterations in HNSCC that may be useful in future therapies. Therefore, it is necessary to identify new biomarkers that may provide a better prediction of the disease and promising targets for personalized therapy. The poor response of HNSCC to therapy is attributed to a small population of tumor cells called cancer stem cells (CSCs). Growing evidence indicates that the Hedgehog (HH) signaling pathway plays a crucial role in the development and maintenance of head and neck tissues. The HH pathway is normally involved in embryogenesis, stem cell renewal, and tissue regeneration. However, abnormal activation of the HH pathway is also associated with carcinogenesis and CSC regulation. Overactivation of the HH pathway was...
International Journal of Cancer, 2012
Glioblastoma multiforme (GBM) is composed of heterogeneous and genetically different cells, which are highly invasive and motile. The standard chemotherapeutic agent, temozolomide, affects GBM cell proliferation but is generally unable to prevent tumor recurrence. Hedgehog pathway activation has been reported to be relevant in GBM and different pharmacological pathway modulators have been identified. We report that by growing a commercially available recurrent GBM cell line (DBTRG-05MG) without serum and in the presence of defined growth factors; we obtained a less differentiated cell population, growing in suspension as neurospheres, in which the Hedgehog pathway is activated. Furthermore, the expression profile of Hedgehog pathway components found in DBTRG-05MG neurospheres is similar to primary stem-like cells derived from recurrent GBM patients. We report the effect of our novel specific Smoothened receptor antagonist (SEN450) on neurosphere growing cells and compared its effect to that of well known benchmark compounds. Finally, we showed that SEN450 is both antiproliferative on its own and further reduces tumor volume after temozolomide pretreatment in a mouse xenograft model using DBTRG-05MG neurosphere cells. Altogether our data indicate that the Hedgehog pathway is not irreversibly switched off in adherent cells but can be reactivated when exposed to well-defined culture conditions, thus restoring the condition observed in primary tumor-derived material, and that pharmacological modulation of this pathway can have profound influences on tumor proliferation. Therefore, pharmacological inhibition of the Hedgehog pathway is a potentially useful therapeutic approach in GBM. Glioblastoma (GBM) represents the most malignant and lethal among brain tumors because of its high infiltration capacity and invasion into the normal brain, resulting in high rates of tumor recurrence following surgery and chemotherapic/radiotherapic treatments. 1 Despite new therapeutic approaches developed in the last decade, the average survival of GBM patients is around 1 year. The identification of new relevant therapeutic targets in brain tumors can provide new ways to approach and treat these tumors. The increasing evidence that cancers might contain and arise from stem cells, named cancer stem-like cells (CSC), has led to a potential understanding of the origin of the tumor bulk and the capability to reinitiate tumor development after standard of care treatment. 3 Although initially the cancer stem cell hypothesis asserted that solid tumors were exclusively maintained and initiated by a rare fraction of Prominin-1 (CD133) positive cancer cells with stem cell properties, 4 there is an ongoing debate about the exact identity and behavior of these cells. 5,6 Different putative neural and/or cancer stem markers used for the identification of this tumor cell subpopulation include Nestin, CD133, SOX2, Nanog, BMI1 and Musashi1. 4, In glioblastoma, the alkylating agent, and standard of care chemotherapy, temozolomide (TMZ) has been demonstrated to reduce the proliferation and survival of glioma cells but was often shown to be unable to prevent tumor recurrence. Moreover, the recurrent tumors are very often completely insensitive to temozolomide. It has been suggested that it is the CSC cell population that remains after standard of care treatment, and being less sensitive to the standard chemotherapies and radiotherapies, this population ultimately gives rise to recurrent tumors. 9,10 On the basis of
The role of the Hedgehog signaling pathway in cancer A comprehensive review
The Hedgehog (Hh) signaling pathway was first identified in the common fruit fly. It is a highly conserved evolutionary pathway of signal transmission from the cell membrane to the nucleus. The Hh signaling pathway plays an important role in the embryonic development. It exerts its biological effects through a signaling cascade that culminates in a change of balance between activator and repressor forms of glioma-associated oncogene (Gli) transcription factors. The components of the Hh signaling pathway involved in the signaling transfer to the Gli transcription factors include Hedgehog ligands (Sonic Hh [SHh], Indian Hh [IHh], and Desert Hh [DHh]), Patched receptor (Ptch1, Ptch2), Smoothened receptor (Smo), Suppressor of fused homolog (Sufu), kinesin protein Kif7, protein kinase A (PKA), and cyclic adenosine monophosphate (cAMP). The activator form of Gli travels to the nucleus and stimulates the transcription of the target genes by binding to their promoters. The main target genes of the Hh signaling pathway are PTCH1 , PTCH2 , and GLI1 . Deregulation of the Hh signaling pathway is associated with developmental anomalies and cancer, including Gorlin syndrome, and sporadic cancers, such as basal cell carcinoma, medulloblastoma, pancreatic, breast, colon, ovarian, and small-cell lung carcinomas. The aberrant activation of the Hh signaling pathway is caused by mutations in the related genes (ligand-independent signaling) or by the excessive expression of the Hh signaling molecules (ligand-dependent signaling – autocrine or paracrine). Several Hh signaling pathway inhibitors, such as vismodegib and sonidegib, have been developed for cancer treatment. These drugs are regarded as promising cancer therapies, especially for patients with refractory/advanced cancers.
Hedgehog Signaling: An emerging targeting therapy in Cancer
Asian Journal of Pharmacy and Pharmacology
Stem cell biology has come of an age. During the past few years, CSCs have been increasingly found in many malignancies. Tumor relapse and metastasis remains major hurdle for improving overall cancer survival. CSCs basically have slow growth rates and are resistant to chemotherapy and/or radiotherapy. Thus, new treatment strategies targeting CSCs can be developed. Various stem cell maintenance pathways such as Notch, Wnt and Hedgehog are found to be activated in the various cancers stem cells. Hedgehog signaling is most active during the embryonic development and aberrant reactivation of the pathway in adult tissue can lead to development of cancer. A variety of cancers such as brain, gastrointestinal, lung, breast and prostate cancer shows possible signs of activation of Hedgehog pathway. Targeted inhibition of Hedgehog signaling can be found effective in the treatment and prevention of many types of human cancers. Hence, the discovery and synthesis of specific Hedgehog pathway inhibitors may have significant clinical implications in novel cancer therapeutics. In this review, we have discussed Hedgehog signaling and its activation in different types of cancers and the development of its targeted therapies.
Hedgehog signalling pathway: Carcinogenesis and targeted therapy
Iranian Journal of Cancer Prevention, 2013
Hedgehog signalling pathway has not only a critical role in cell proliferation, differentiation and tissue polarity at embryonic period but also has a vital role in stem cell proliferation, tissue healing and carcinogenesis. Recent research has increased our understanding of this pathway and its relation to other signalling pathways. In addition, a large number of studies confirmed the alteration of Hh signalling pathway in various types of human malignancies including basal cell carcinomas, medulloblastomas, lung, gastrointestinal, ovarian, breast, prostate cancers and leukemia. More than 50 small biomolecules have been introduced which have inhibitory effects on Hh signalling pathway. Although, in many tumors some acceptable results have been showed in phase I clinical trial, closer studies are required to improve drug bioavailability, to decrease the side effects and to find the right small molecules for specific types of cancers, considering patients overall benefits as well.