apicidin and Neoplasms

Interleukin-8 (IL-8) and heat shock protein 60 (Hsp60) play crucial roles in cell survival and maintenance of cellular homoeostasis. However, cross talks between these two proteins are not defined.. IL-8 expression in tumour tissue sections was analysed by immunohistochemistry. IL-8 expression and release in cancer cells was quantified using enzyme-linked immunosorbent assay (ELISA). Apoptosis was quantified using caspase activity and Annexin-V/PI staining.. We observed IL-8 release from cancer cells in response to histone deacetylase inhibitor, apicidin (Api), and non-competitive inhibitor of the sarco/endoplasmic reticulum Ca. This study describes the underlying mechanism associated with apoptosis resistance mediated via Hsp60-IL-8 axis in cancer.

Topics: Animals; Apoptosis; Caspase 8; Caspase 9; Chaperonin 60; Gene Knockdown Techniques; HCT116 Cells; Heterografts; Humans; Interleukin-8; Male; Mice; Mice, SCID; Mitochondrial Proteins; Neoplasms; PC-3 Cells; Peptides, Cyclic; Signal Transduction; Thapsigargin

Nutlin-3, a small-molecule MDM2 inhibitor, restores p53 function and is, thus, an appealing candidate for the treatment of cancers retaining wild-type p53. However, nutlin-3 applied as single agent may be insufficient for cancer therapy. Therefore, we explored whether the anticancer activity of nutlin-3 could be enhanced by combination with histone deacetylase inhibitors (HDACi), i.e. vorinostat, sodium butyrate, MS-275 and apicidin. We found that nutlin-3 and HDACi cooperated to induce cell death in the p53 wild-type cell lines A549 and A2780, but not in the p53 null cell line PC-3, as assessed by Alamar Blue assay and flow cytometric analyses of propidium iodide uptake and mitochondrial depolarization. Combination index analysis showed that the effect was synergistic. For comparison, we tested nutlin-3 in combination with paclitaxel, revealing that nutlin-3 antagonized the cytotoxic activity of paclitaxel. To shed light on the underlying mechanism of the synergistic action of nutlin-3 and HDACi, we determined the acetylation status of p53 by immunoblotting and the mRNA levels of MDM2 and MDM4 by real-time RT-PCR. We observed vorinostat to induce p53 hyperacetylation, to reduce the constitutive gene expression of MDM2 and MDM4, and to counteract the nutlin-3-induced upregulation of MDM2 gene expression. In conclusion, our study shows that HDACi amplify the antitumor activity of nutlin-3-possibly by inducing p53 hyperacetylation and/or MDM2 and/or MDM4 downregulation-suggesting that treatment with a combination of nutlin-3 and HDACi may be an effective strategy for treating tumors with wild-type p53.

Topics: Acetylation; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Blotting, Western; Butyrates; Cell Cycle Proteins; Cell Death; Cell Line, Tumor; Dose-Response Relationship, Drug; Down-Regulation; Drug Synergism; Flow Cytometry; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Imidazoles; Neoplasms; Nuclear Proteins; Paclitaxel; Peptides, Cyclic; Piperazines; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-mdm2; Pyridines; Real-Time Polymerase Chain Reaction; RNA, Messenger; Tumor Suppressor Protein p53; Vorinostat