Inhibitory Activities of Trichostatin A in U87 Glioblastoma Cells and Tumorsphere-Derived Cells

Abstract

Epigenetic alterations have been increasingly implicated in glioblastoma (GBM) pathogenesis, and epigenetic modulators including histone deacetylase inhibitors (HDACis) have been investigated as candidate therapies. GBMs are proposed to contain a subpopulation of glioblastoma stem cells (GSCs) that sustain tumor progression and therapeutic resistance and can form tumorspheres in culture. Here, we investigate the effects of the HDACi trichostatin A (TSA) in U87 GBM cultures and tumorsphere-derived cells. Using approaches that include a novel method to measure tumorsphere sizes and the area covered by spheres in GBM cultures, as well as a nuclear morphometric analysis, we show that TSA reduced proliferation and colony sizes, led to G2/M arrest, induced alterations in nuclear morphology consistent with cell senescence, and increased the protein content of GFAP, but did not affect migration, in cultured human U87 GBM cells. In cells expanded in tumorsphere assays, TSA reduced sphere formation and induced neuron-like morphological changes. The expression of stemness markers in these cells was detected by reverse transcriptase polymerase chain reaction. These findings indicate that HDACis can inhibit proliferation, survival, and tumorsphere formation, and promote differentiation of U87 GBM cells, providing further evidence for the development of HDACis as potential therapeutics against GBM.

Spheres from cervical cancer cells display stemness and cancer drug resistance

“…At present, the sorting methods of CSCs include flow cytometry based on special cell surface markers, the side population cell sorting technique, tumor sphere culturing and the ALDEFLUOR™ assay (6)(7)(8)(9). Previous studies have identified the CSCs from colon, breast and glioblastoma cancer, as well as other cancer cell lines, using the sphere culturing method (10)(11)(12). Tumor cell sphere culturing may be a convenient method for generating cancer stem-like cells to be used in the research of malignant behavior.…”

Pharmacological Properties of Trichostatin A, Focusing on the Anticancer Potential: A Comprehensive Review

“…Research findings showed that TSA inhibits differentiation and proliferation and tumor sphere formation of glioblastoma (GBM) [ 52 , 141 , 142 ]. In addition, TSA upregulated the expression of numerous tumor suppressor genes through epigenetic modification in GBM [ 143 ].…”

“…The TSA-induced cell cycle arrest in GBM was associated with the upregulation of p21 WAF1 and p53, and the downregulation of cell cycle regulators such as cdk4 and 6, and cyclin D1 with the reduction in phosphorylated Rb and Akt [ 141 , 142 , 144 , 145 ]. Sassi et al [ 52 ] reported that TSA inhibited the proliferation and colony formation of U87 glioblastoma cells without affecting their viability and migration. Similarly, Hoering et al [ 27 ] showed that TSA induces apoptosis of tumor cells, enhances the sensibility of GBM cells to innate immune responses in vitro and delays tumor growth of GBM xenografts in vivo .…”

Molecular imaging HDACs class IIa expression-activity and pharmacologic inhibition in intracerebral glioma models in rats using PET/CT/(MRI) with [18F]TFAHA

“…Many novel inhibitors of these key epigenetic regulatory enzymes have been developed and tested in clinical trials 2 . It has been demonstrated, that HDAC inhibitors sensitize gliomas and other types of cancer to chemotherapeutic agents and radiation, including: trichostatin (TSA), SAHA (vorinostat), valproic acid (VPA), LBH589 (panobinostat), MS275 (entinostat), PXD101 (belinostat) 3–19 . Studies in patient-derived glioblastoma cells demonstrated that SAHA, VPA, MS275, LBH589 and Scriptaid are effective radiosensitizers of gliomas 20 .…”

“…A growing number of reports underscore the important roles of HDAC class IIa enzymes (HDAC4, 5, 7, 9) in GBM progression 3,25–29 , invasion 30–32 , responses to TMZ and radiotherapy 4,21,22 , and prognosis 33 . However, no studies have been reported to date on the efficacy of HDACs class IIa-selective inhibitors alone or in combination with TMZ and radiation therapy of GBM.…”