carboxycinnamic-acid-bishydroxamide and Adenocarcinoma

Histone deacetylase inhibitors (HDACIs) have got immense importance as promising drugs for cancer treatment as these inhibitors regulate cellular differentiation, gene expression, cell cycle arrest and apoptosis. The current study investigates the effect of the hybrid-polar HDACI m-carboxycinnamic acid bishydroxyamide (CBHA) on the growth of human pancreatic adenocarcinoma cells, using the cell line MIA PaCa- 2 as an in vitro model.. Following CBHA treatment of the MIA PaCa-2 cells, we characterized the effect of CBHA by in vitro cytotoxicity evaluation, clonogenic assay, cell cycle analysis, immunoblotting for soluble and insoluble fractions of tubulin, immunofluorescence and caspase-3 assay.. We observed that the histone deacetylase inhibitor CBHA markedly impaired growth of the pancreatic cancer cells by resulting in dose-dependent G2/M arrest, disruption of microtubule organization, induction of caspase-mediated apoptosis and in vitro suppression of HDAC6. Our study also shows that inhibition of HDAC6 by CBHA induced acetylation of α-tubulin.. Together, our findings show that CBHA can be a potential plausible therapeutic that could be exploited for pancreatic cancer therapy.

Topics: Adenocarcinoma; Antineoplastic Agents; Cell Cycle; Cell Proliferation; Cinnamates; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Histone Deacetylase 6; Histone Deacetylase Inhibitors; Humans; Molecular Structure; Pancreatic Neoplasms; Structure-Activity Relationship; Tumor Cells, Cultured

HDAC inhibitors induce histone hyperacetylation by a relative increase of histone acetyltransferase activity. Histone hyperacetylation may affect chromatin structure and susceptibility to DNA-damaging stress, such as IR. We here investigate whether these inhibitors can radiosensitize human gastric MKN45 and colorectal DLD1 adenocarcinoma cells. In both cells, FK228 pretreatment at minimally toxic concentrations clearly augmented IR-induced cell death, DNA fragmentation and caspase-3/-8 activation. In contrast, 5-FU did not clearly augment IR-induced cell death and caspase-3 activation. FK228 increased expression of proapoptotic BH3-only Bim proteins, and gene transfer-mediated overexpression of Bimalpha radiosensitized DLD1 cells. These data suggest that the FK228-mediated increase of Bim expression may at least partially contribute to its augmentation of radiation-induced apoptosis. However, FK228 did not distinctly affect IR-induced phosphorylation of H2AX, which is an initial event followed by DNA damage. FK228 strongly augmented IR-induced growth suppression of MKN45 tumor xenografts. In addition, other HDAC inhibitors, MS275 and CBHA, similarly augmented IR-induced cell death in both cell types. Our results suggest that these HDAC inhibitors may enhance the efficacy of radiation therapy in gastrointestinal cancer cells.

Topics: Adenocarcinoma; Animals; Apoptosis; Apoptosis Regulatory Proteins; Bcl-2-Like Protein 11; Benzamides; Carrier Proteins; Cell Line, Tumor; Cinnamates; Depsipeptides; Enzyme Inhibitors; Gastrointestinal Neoplasms; Histone Deacetylase Inhibitors; Humans; Membrane Proteins; Mice; Peptides, Cyclic; Phosphorylation; Proto-Oncogene Proteins; Pyridines; Radiation-Sensitizing Agents; RNA, Messenger

We investigated whether the histone deacetylase inhibitors m-carboxycinnamic acid bis-hydroxamide (CBHA) and a bicyclic depsipeptide, FK228, can enhance the anticancer effect of the proteasome inhibitors PSI and PS-341 in gastrointestinal carcinoma cells.. The anticancer effect of CBHA or FK228 and PSI or PS-341 was evaluated by cell death, caspase-3 activity, externalization of phosphatidylserine and DNA fragmentation, and colony formation assay. Expression of apoptosis-related molecules and cell cycle regulatory molecules, as well as phosphorylation of p38 were investigated by immunoblots. Generation of reactive oxygen species (ROS) was detected by intracellular oxidation of 5- (and-6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate.. CBHA or FK228 plus PSI or PS-341 synergistically induced apoptosis in human colonic DLD-1 and gastric MKN45 carcinoma cell lines. CBHA or FK228, but not 5-fluorouracil, plus PS-341 strongly decreased plating efficiency of DLD-1 cells. FK228 elicited ROS generation, and the free radical scavenger l-N-acetylcysteine inhibited the synergistic anticancer effect of combined therapy. In addition, l-N-acetylcysteine inhibited the combined therapy-mediated elevation of a proapoptotic BH3-only protein Bim expression, phosphorylation of H2AX, and accumulation of 8-hydroxydeoxyguanosine.. FK228 or CBHA and PSI or PS-341 synergistically induce apoptosis in DLD-1 and MKN45 cells depending on ROS-mediated signals. Our data suggest that a combination of FK228 or CBHA with PSI or PS-341 may be a valuable therapy against gastrointestinal adenocarcinoma cells.

Topics: Adenocarcinoma; Annexin A5; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Boronic Acids; Bortezomib; Caspase 3; Caspases; Cell Line, Tumor; Cinnamates; Colonic Neoplasms; Depsipeptides; DNA Fragmentation; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Inhibitors; Free Radicals; Gastrointestinal Neoplasms; Histones; Humans; Microscopy, Confocal; Oligopeptides; Oxygen; Phosphorylation; Proteasome Inhibitors; Pyrazines; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Time Factors