apicidin and Endometrial-Neoplasms

It has recently been reported that endometrial cancer cells are able to convert estron (E1) to 17β estradiol (E2). We observed the presence of 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) transcript and protein in receptor positive ER(+) and negative ER(-) Ishikawa endometrial adenocarcinoma (ISH) cells. ER(+) ISH, but not ER(-)02 ISH, cells were significantly susceptible to apicidin induced death, and we further used ER(-)ISH cells to study the effect of apicidin on cellular levels of HSD17B1 transcript and protein. We showed that apicidin significantly lowered HSD17B1 transcript and protein levels in ISH cells. There was no significant effect on HSD17B1 transcript stability. However, chromatin immunoprecipitation analysis revealed that apicidin significantly decreased occupation of the first exon of the HSD17B1 gene by Polymerase II. Since intratumoral E1 to E2 conversion is a significant contributor to the progression of estrogen dependent cancers, and HDAC inhibitors are being tested in anticancer clinical trials, our observations may have clinical value.

Topics: 17-Hydroxysteroid Dehydrogenases; Adenocarcinoma; Animals; Endometrial Neoplasms; Estradiol; Female; Histone Deacetylase Inhibitors; Humans; Peptides, Cyclic; Receptors, Estrogen; RNA Stability; Transcription, Genetic; Tumor Cells, Cultured

Histone deacetylase (HDAC) inhibitors are a new class of anticancer agents that act by inhibiting cancer cell proliferation and inducing apoptosis both in vitro and in vivo. This study examined the anti-tumor effect of apicidin on human endometrial cancer Ishikawa cells in an animal model by inhibiting specific HDAC expression. Nude mice were injected subcutaneously (s.c.) with Ishikawa cells, and the levels of cell proliferation and apoptosis were measured in the tumor tissues after an apicidin treatment. The expression patterns of a specific HDAC class by apicidin were measured in Ishikawa endometrial cancer both in vitro and in vivo. The tumor volume and weight were measured after the apicidin treatment. Apicidin significantly increased the acetylated histone H3 levels in an Ishikawa cells in vitro culture but the levels of HDAC3 and HDAC4 expression were significantly decreased. Apicidin suppressed the tumor growth of transplanted Ishikawa cells, the expression of proliferative cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) in tumor xenograft model, respectively. The inhibitory effect of apicidin on tumor growth was mediated in part through the down-regulation of HDAC3 and HDAC4. We suggest that apicidin is an effective anti-tumor agent on human endometrial cancer cells, and acts by regulating cell proliferation and apoptosis through the down-regulation of HDAC3 and HDAC4.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Endometrial Neoplasms; Female; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Peptides, Cyclic; Repressor Proteins

Overexpression of histone deacetylases has been reported in various human malignancies; however, the expression of histone deacetylases in endometrial tissue is not fully understood. In the present study, the expression of histone deacetylase 1, histone deacetylase 2, and Ki-67 was examined immunohistochemically in 30 normal and 66 malignant endometrial tissue samples. The results were expressed as a positivity index and compared with the positivity index for Ki-67 and rates of patient survival. The effect of 2 histone deacetylase inhibitors, trichostatin A and apicidine, on cell proliferation and the expression of cell cycle regulators such as cyclins (D1, E, and A), p21, p27, and p16 were investigated using 6 endometrial carcinoma cell lines. The positivity index for histone deacetylase 1 (79.8 +/- 33.0, mean +/- SD) and histone deacetylase 2 (106.3 +/- 41.9) was higher in endometrial carcinoma than the normal endometrium, with a significant difference for histone deacetylase 2. The positivity index for histone deacetylase 2 was significantly increased in higher-grade carcinomas (positivity index for grade 3, 124.9 +/- 28.4) compared with grade 1 tumors (86.0 +/- 41.0) and was positively correlated with that for Ki-67. In addition, patients with histone deacetylase 2-positive carcinomas had a poor prognosis compared with those with histone deacetylase 2-negative carcinoma (P = .048). Treatment with trichostatin A or apicidine suppressed the proliferation in all cell lines examined, in association with increased expression of p21 and down-regulation of cyclin D1 and cyclin A expression. These results indicated that increased histone deacetylase 2 expression is involved in the acquisition of aggressive behavior by endometrial carcinoma and suggest histone deacetylase inhibitor to be a promising anticancer drug for this carcinoma.

Topics: Adult; Aged; Apoptosis; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Endometrial Neoplasms; Endometrium; Female; Histone Deacetylase 1; Histone Deacetylase 2; Humans; Hydroxamic Acids; Immunohistochemistry; Ki-67 Antigen; Middle Aged; Peptides, Cyclic; Prognosis; Survival Analysis

Histone deacetylase (HDAC) inhibitors are a promising new class of anticancer agents that act by inhibiting cell proliferation and inducing apoptosis in a variety of cancer cells. Although apicidin acts as a potent HDAC inhibitor, the precise mechanism for its anti-tumor activity in human endometrial cancer cells is not completely understood. This study examined the anti-tumor effects of apicidin in Ishikawa cancer cells. The level of cell proliferation, the stage of the cell cycle, and apoptosis were measured after the apicidin treatment. Apicidin significantly inhibited the proliferation of Ishikawa cells in a dose-dependent manner. In addition, apicidin markedly up-regulated the p21(WAF1) and down-regulated the expression of cyclins (A, B1, D1, or E), and CDKs (2 or 4), which leading to cell cycle arrest. Cell cycle analysis showed that the apicidin treatment increased the proportion of cells in the G1 phase, and decreased the ratio of cells in the S phase in a dose-dependent manner. Apicidin significantly increased the sub-G1 population and the number of TUNEL positive apoptotic cells compared with the untreated control. These results were confirmed by poly-ADP ribose polymerase (PARP), an 85-kDa fragment resulting from PARP cleavage, where apicidin increased the level of PARP cleavage and caspase-3 activity in 1.0 microM apicidin-treated cells. Apicidin-induced apoptosis through caspase-3 activation was confirmed by the increase in the release of cytochrome c and the decrease in the Bax/Bcl-2 ratio. These results suggest that apicidin has anti-tumor properties on endometrial cancer cells by inducing selectively the genes related to cell cycle arrest and apoptosis.

Topics: Antineoplastic Agents; Apoptosis; Blotting, Western; Caspase 3; Cell Cycle; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; Cytochromes c; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Endometrial Neoplasms; Female; G1 Phase; Gene Expression Regulation, Neoplastic; Histones; Humans; Peptides, Cyclic; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; Tumor Cells, Cultured

Histone deacetylase inhibitors (HDACIs) can inhibit proliferation, induce cell cycle arrest and stimulate apoptosis of cancer cells. Our purpose was to investigate the antiproliferative effects of a novel HDACI, apicidin, on the Ishikawa endometrial cancer cell line, the SK-OV-3 ovarian cancer cell line and normal human endometrial epithelial cells. Endometrial and ovarian cancer cells were treated with various concentrations of apicidin, and the effects on cell growth, cell cycle, apoptosis and related measurements were investigated. MTT assays showed that all endometrial and ovarian cancer cell lines were sensitive to the growth inhibitory effect of apicidin, although normal endometrial epithelial cells were viable after the treatment with the same doses of apicidin that induced the growth inhibition of endometrial and ovarian cancer cells. Cell cycle analysis indicated that their exposure to apicidin decreased the proportion of cells in S-phase and increased the proportion in G0/G1 and/or G2/M phases of the cell cycle. Induction of apoptosis was confirmed by Annexin V staining of externalized phosphatidylserine and loss of the transmembrane potential of mitochondria. This induction occurred in concert with the altered expression of p21WAF1, p27KIP1, p16, cyclin A, and E-cadherin. Furthermore, apicidin treatment of these cell lines increased acetylation of H3 and H4 histone tails. These results suggest that apicidin exhibits the antiproliferative effects through selective induction of genes related to cell growth, malignant phenotype, and apoptosis. The findings raise the possibility that apicidin may prove particularly effective in the treatment of endometrial and ovarian cancers.

Topics: Acetylation; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Endometrial Neoplasms; Enzyme Inhibitors; Female; Histone Deacetylase Inhibitors; Histone Deacetylases; Histones; Humans; Membrane Potential, Mitochondrial; Molecular Structure; Ovarian Neoplasms; Peptides, Cyclic