trichostatin-a and Precursor-B-Cell-Lymphoblastic-Leukemia-Lymphoma

Trichostatin A (TSA) is a well-known histone deacetylases (HDACs) inhibitor that has been reported to show potent anti-tumor capabilities in some types of cancer cell lines. However, detailed mechanism of TSA action on lymphoma remains to be described. In the present study, anti-proliferative effects of TSA were investigated using a murine pro-B lymphoma cell line FL5.12. MTT assay revealed that TSA potently inhibited the proliferation of FL5.12 cells in a time- and dose-dependent manner. Bright-field microscopy of FL5.12 cells showed apoptotic morphology at 24 h after TSA treatment. Consistently, TSA treatment led to DNA fragmentation and increased the protein levels of cleaved caspase 3 and PARP as revealed by western blot analysis. To explore the underlying mechanism of TSA-induced apoptosis of FL5.12 cells, we further analyzed the hematopoietic transcription factor Purine Rich Box-1 (PU.1) by western blot analysis. TSA treatment resulted in the inhibition of PU.1 in FL5.12 cells. In contrast, apoptotic protein Bim was induced by TSA, which was inversely correlated with the survival of FL5.12 cells. These results suggest the possible mechanism of TSA-induced apoptosis in murine pro-B lymphoma FL5.12 cells via the PU.1-Bim axis.

Topics: Animals; Antineoplastic Agents; Apoptosis; Bcl-2-Like Protein 11; Caspase 3; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Histone Deacetylase Inhibitors; Hydroxamic Acids; Mice; Models, Biological; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma; Proto-Oncogene Proteins; Signal Transduction; Trans-Activators

The connective tissue growth factor gene (CTGF) is aberrantly expressed in 75% of precursor B-cell acute lymphoblastic leukaemias (pre-B ALL) and is associated with poor outcome. We identified consistent hypomethylation of the CTGF locus in primary pre-B ALL specimens regardless of CTGF expression. By contrast, primary T-cell ALL specimens, which do not express CTGF, exhibited distinctive patterns of hypermethylation. Furthermore, we confirmed that global changes in DNA methylation and histone acetylation can both functionally modulate CTGF expression in pre-B ALL cell lines. These data suggest that hypomethylation of the CTGF locus is an essential prerequisite for aberrant CTGF expression in pre-B ALL.

Topics: Azacitidine; Cells, Cultured; Child; Connective Tissue Growth Factor; CpG Islands; Decitabine; DNA Methylation; Gene Expression Regulation, Leukemic; Humans; Hydroxamic Acids; Jurkat Cells; Neoplasm Proteins; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma; Real-Time Polymerase Chain Reaction; RNA, Messenger; RNA, Neoplasm; Sequence Analysis, DNA

Despite advances in the treatment of ALL, in most patients long-term survival rates remain unsatisfactory. The objective of the present study was to investigate the anti-cancer effects of Prostaglandin E2 (PGE2) in two different ALL cell lines (CCRF-CEM (T-ALL) and Nalm-6 (B-ALL)). The anti-leukemic effects of PGE2 were also compared with two epigenetic compounds (trichostatin A and 5-aza-2'-deoxycytidine). MTT assay was used to assess growth inhibition by anti-cancer drugs in these cells. All three compounds were shown to induce apoptosis in both ALL cell lines using flow cytometry and Western blotting. To evaluate the differentiation induction by these agents, the expressions of CD19 and CD38 markers on Nalm-6 cell line and CD7 marker on CCRF-CEM cell line were assayed. Surprisingly, the flow cytometric analysis showed a significant increase in CD markers expression in response to PGE2 treatments. We, for the first time, provide evidences that PGE2 has anti-leukemic effects and induces differentiation at micromolar ranges in both T- and B-cell derived ALL cell lines. Since T-ALL cells are insensitive to current chemotherapies, these findings may help the designing of new protocols for T-ALL differentiation therapy in the future.

Topics: Antineoplastic Agents; Apoptosis; Azacitidine; Caspase 3; Cell Cycle; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Decitabine; Dinoprostone; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Flow Cytometry; Humans; Hydroxamic Acids; Inhibitory Concentration 50; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma