panobinostat and Carcinoma--Squamous-Cell

Combination therapy has been widely explored for oncolytic virus (OV), as it can be met with tumor resistance. The HDAC inhibitor (HDACi) panobinostat is a potent pan-deacetylase inhibitor which blocks multiple cancer-related pathways and reverses epigenetic events in cancer progression.. In this study, oncolytic activity in vitro and antitumor therapeutic efficacy in vivo when combined with oHSV and panobinostat were investigated.. (1) Treatment with panobinostat enhanced oHSV propagation and cytotoxicity in human glioma A172 and squamous cell carcinoma SCC9 cells. (2) Combined treatment with oHSV and panobinostat enhanced virus replication mediated by the transcriptional downregulation of IFN-β- and IFN-responsive antiviral genes in human glioma A172 and squamous cell carcinoma SCC9 cells. (3) Panobinostat treatment induced upregulation of PD-L1 expression in both glioma and squamous cell carcinoma cells. (4) A significantly enhanced therapeutic efficacy was shown in vivo for the murine glioma CT-2A and squamous cell carcinoma SCC7 models when treated with a combination of oHSV, including PD-1/PD-L1 blockade and HDAC inhibition.. Consequently, these data provide some new clues for the clinical development of combination therapy with OVs, epigenetic modifiers, and checkpoint blockades for glioma and squamous cell carcinoma.

Topics: Animals; B7-H1 Antigen; Carcinoma, Squamous Cell; Cell Line, Tumor; Glioma; Histone Deacetylase Inhibitors; Humans; Mice; Oncolytic Virotherapy; Oncolytic Viruses; Panobinostat; Programmed Cell Death 1 Receptor; Simplexvirus

Topics: Actins; Adenocarcinoma of Lung; Animals; Antineoplastic Agents; ATPases Associated with Diverse Cellular Activities; Carcinoma, Squamous Cell; Chromatin; Chromosomal Proteins, Non-Histone; Cisplatin; DNA Adducts; DNA Damage; DNA Repair; DNA-Binding Proteins; DNA, Neoplasm; Drug Resistance, Neoplasm; Female; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Lung Neoplasms; Lysine Acetyltransferase 5; Mice; Ovarian Neoplasms; Panobinostat; Survival Analysis; Transcription Factors; Xenograft Model Antitumor Assays

Inhibitors of histone deacetylases (HDACs) represent a novel class of therapeutic anticancer agents. Panobinostat (LBH589) induces apoptosis through the regulation of specificity protein 1 (Sp1) in the oral squamous cell carcinoma (OSCC) cell lines, HN22 and HSC4. In this study, we analyzed the underlying signaling pathways and the mechanisms involved in this process by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, 4',6-diamidino-2-phenylindole (DAPI) staining, immunocytochemistry and western blot analysis. LBH589 significantly reduced cell growth and the sub-G1 cell population and induced apoptosis. Sp1 protein expression was significantly reduced following treatment with LBH589 in a concentration-dependent manner. Furthermore, LBH589 upregulated the expression of p27 and p21 and downregulated the expression of cyclin D1, myeloid cell leukemia-1 (Mcl-1) and survivin; this led to the activation of apoptotic signaling pathways through the increase of Bax expression and the decrease of Bid and Bcl-xL expression. Treatment with LBH589 also induced the cleavage of caspase-3 and PARP in the HN22 and HSC4 cells. Taken together, our data demonstrate that LBH589 induces the apoptosis of OSCC cells by suppressing Sp1 expression, indicating that LBH589 may be a promising chemotherapeutic agent for the treatment of OSCC.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Indoles; Mouth Neoplasms; Panobinostat; Signal Transduction; Sp1 Transcription Factor; Tetrazolium Salts; Thiazoles

The development of clinically useful histone deacetylase inhibitors has expanded greatly. In a preclinical study, we showed that panobinostat (LBH589) inhibits cell cycle progression of human head and neck squamous cell carcinoma (HNSCC) cell lines at G₂/M and an associated decrease in expression of particular genes required for passage through G₂ and mitosis. In this study we sought to analyse the mechanistic underpinnings of panobinostat-induced growth arrest. HNSCC cell lines were synchronised and progression through mitosis monitored. We demonstrate that panobinostat causes a marked G₂ delay and mitotic defects. A loss of G₂-specific Plk1 and Cyclin B1 expression and co-incident increase in p21(Waf1/Cip1) expression is also shown. Furthermore, we show a significant loss of E2F1 recruitment to the promoters of these genes in response to panobinostat treatment. These data provide mechanistic evidence of panobinostat-induced cell cycle arrest and highlight its potential as a chemotherapeutic agent for HNSCC.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Cycle Checkpoints; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cyclin B1; Cyclin-Dependent Kinase Inhibitor p21; E2F1 Transcription Factor; G2 Phase; Gene Expression Regulation; Head and Neck Neoplasms; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Mitosis; Panobinostat; Polo-Like Kinase 1; Promoter Regions, Genetic; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Squamous Cell Carcinoma of Head and Neck

We examine the potential value of a series of clinically relevant PI3K-mTOR inhibitors alone, or in combination with histone deacetylase inhibitors, in a model of head and neck squamous cell carcinoma (HNSCC).. Head and neck squamous cell carcinoma cell lines, human keratinocyte and HNSCC xenograft models were treated with histone deacetylase inhibitors (HDACIs) and new generation PI3K and dual PI3K-mTOR inhibitors either alone or in combination. Cell and tumour tissue viability and proliferation were then determined in vitro and in vivo.. Phosphatidylinositol-3-phosphate kinase, AKT and dual PI3K-mTOR inhibitors caused marked in vitro enhancement of cytotoxicity induced by HDACIs in HNSCC cancer cells. This effect correlates with AKT inhibition and is attenuated by expression of constitutively active AKT. Histone deacetylase inhibitor and phosphatidylinositol-3-phosphate kinase inhibitors (PI3KIs) inhibited tumour growth in xenograft models of HNSCC. Importantly, we observed intratumoural HDAC inhibition and PI3K inhibition as assessed by histone H3 acetylation status and phospho-AKT staining, respectively. However, we saw no evidence of improved efficacy with an HDACI/PI3KI combination.. That PI3K and dual PI3K-mTOR inhibitors possess antitumour effect against HNSCC in vivo.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Drug Evaluation, Preclinical; Female; Head and Neck Neoplasms; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Immunohistochemistry; Indoles; Mice; Mice, Inbred NOD; Mice, SCID; Panobinostat; Phosphoinositide-3 Kinase Inhibitors; TOR Serine-Threonine Kinases; Vorinostat

Head and neck squamous cell carcinoma represents a complex set of neoplasms arising in diverse anatomical locations. The site and stage of the cancer determine whether patients will be treated with single or multi-modality therapy. The HDAC inhibitor LBH589 is effective in treating some haematological neoplasms and shows promise for certain epithelial neoplasms. As with other human cancer cell lines, LBH589 causes up-regulation of p21, G2/M cell cycle arrest, and cell death of human HNSCC cell lines, as measured using flow cytometry and cDNA microarrays. Global RNA expression studies following treatment of the HNSCC cell line FaDu with LBH589 reveal down-regulation of genes required for chromosome congression and segregation (SMC2L1), sister chromatid cohesion (DDX11), and kinetochore structure (CENP-A, CENP-F, and CENP-M); these LBH589-induced changes in gene expression coupled with the down-regulation of MYC and BIRC5 (survivin) provide a plausible explanation for the early mitotic arrest and cell death observed. When LBH589-induced changes in gene expression were compared with gene expression profiles of 41 primary HNSCC samples, many of the genes that were down-regulated by LBH589 showed increased expression in primary HNSCC, suggesting that some patients with HNSCC may respond to treatment with LBH589.

Topics: Adult; Aged; Aged, 80 and over; Carcinoma, Squamous Cell; Cell Death; Cell Line, Tumor; Down-Regulation; Enzyme Inhibitors; Female; Flow Cytometry; G2 Phase; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Male; Middle Aged; Oligonucleotide Array Sequence Analysis; Panobinostat