panobinostat and Mesothelioma

New therapeutic approaches are still needed for effective malignant pleural mesothelioma treatment. The use of classical chemotherapy agents in combination with newly developed molecules may shed light on new therapeutic approaches. We aimed to determine the efficacy of panobinostat, alone and in combination with cisplatin, on cell survival and mRNA expression of FOXO3A, CCND1, and CASP9 genes in both mesothelioma and healthy mesothelial cell lines. Cells were treated with 1-100 µM cisplatin and 25-1000 nM panobinostat. Methylthiazol tetrazolium assays were performed to determine cell viability. mRNA expression levels of genes were analyzed with quantitative real-time polymerase chain reaction. Cisplatin and panobinostat exposure of the cells for 24 h resulted in decreased cell survival. The combined treatment was found to be more effective. No significant changes were observed with respect to CCND1 expression after exposure to agents alone or in combination. However, agents in combination resulted in upregulation of FOXO3A and CASP9 in MSTO-211H cells. Gene expression levels were not affected by any agents in healthy cells. Use of cisplatin in combination with new chemotherapeutic agents may reduce the toxic effects of cisplatin in normal cells and result in more effective removal of tumor cells.

Topics: Antineoplastic Agents; Caspase 9; Cell Line, Tumor; Cell Survival; Cisplatin; Cyclin D1; Forkhead Box Protein O3; Forkhead Transcription Factors; Humans; Hydroxamic Acids; Indoles; Mesothelioma; Panobinostat; RNA, Messenger; Transcription, Genetic

Tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) is a member of tumor necrosis factor family and it is important for ligand induced apoptosis in tumor cells. TRAIL has been shown to be synergistic with a variety of chemotherapies and targeted agents. In the study, a combination of TRAIL and a histone deacetylase inhibitor LBH589 was studied in mesothelioma cell lines.. Five mesothelioma cell lines and two normal cell lines were tested for cell growth inhibition and apoptosis using high-throughput assays in the presence of LBH589, TRAIL and a combination of the two. Caspase induction was studied and levels of X-linked inhibitor of apoptosis (XIAP) were tested using Western blotting. A combination of a direct inhibitor of XIAP was also tested in combination with TRAIL.. In mesothelioma cell lines, a combination of LBH589 and TRAIL markedly increased cell growth inhibition and apoptosis when compared with the effect on normal cell lines. LBH589 and TRAIL appeared to induce higher levels of caspase 3 and 7 and this appeared to be closely related to ability of LBH589 to degrade XIAP. In addition, a direct inhibitor of XIAP was also sensitized cells to TRAIL apoptosis, providing an indirect confirmation for XIAP degradation as a possible mechanism of synergy.. In mesothelioma cell lines, LBH589 increases the sensitivity to TRAIL. In addition, at least partly, the mechanism of this induction of TRAIL sensitivity is due to LBH589 related degradation of XIAP. These results provide initial evidence for testing this combination in clinical trials.

Topics: Acetylation; Apoptosis; BH3 Interacting Domain Death Agonist Protein; Caspases; Cysteine Proteinase Inhibitors; Enzyme Activation; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Immunoblotting; Indoles; Leupeptins; Mesothelioma; Panobinostat; Poly(ADP-ribose) Polymerases; TNF-Related Apoptosis-Inducing Ligand; Tumor Cells, Cultured; X-Linked Inhibitor of Apoptosis Protein

Lung cancer is the leading cause of cancer deaths in the United States. Current therapies are inadequate. Histone deacetylase inhibitors (HDACi) are a recently developed class of anticancer agents that cause increased acetylation of core histones and nonhistone proteins leading to modulation of gene expression and protein activity involved in cancer cell growth and survival pathways. We examined the efficacy of the HDACi panobinostat (LBH589) in a wide range of lung cancers and mesotheliomas. Panobinostat was cytotoxic in almost all 37 cancer cell lines tested. IC(50) and LD(50) values were in the low nmol/L range (4-470 nmol/L; median, 20 nmol/L). Small cell lung cancer (SCLC) cell lines were among the most sensitive lines, with LD(50) values consistently <25 nmol/L. In lung cancer and mesothelioma animal models, panobinostat significantly decreased tumor growth by an average of 62% when compared with vehicle control. Panobinostat was equally effective in immunocompetent and severe combined immunodeficiency mice, indicating that the inhibition of tumor growth by panobinostat was not due to direct immunologic effects. Panobinostat was, however, particularly effective in SCLC xenografts, and the addition of the chemotherapy agent etoposide augmented antitumor effects. Protein analysis of treated tumor biopsies revealed elevated amounts of cell cycle regulators such as p21 and proapoptosis factors, such as caspase 3 and 7 and cleaved poly[ADP-ribose] polymerase, coupled with decreased levels of antiapoptotic factors such as Bcl-2 and Bcl-X(L). These studies together suggest that panobinostat may be a useful adjunct in the treatment of thoracic malignancies, especially SCLC.

Topics: Carcinoma, Small Cell; Cell Line, Tumor; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Indoles; Lung Neoplasms; Mesothelioma; Panobinostat