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World Journal of Gastroenterology Aug 2014To explore the efficacy of PCI-24781, a broad-spectrum, hydroxamic acid-derived histone deacetylase inhibitor, in the treatment of gastric cancer (GC).
AIM
To explore the efficacy of PCI-24781, a broad-spectrum, hydroxamic acid-derived histone deacetylase inhibitor, in the treatment of gastric cancer (GC).
METHODS
With or without treatment of PCI-24781 and/or cis-diamminedichloroplatinum (CDDP), GC cell lines were subjected to functional analysis, including cell growth, apoptosis and clonogenic assays. Chromatin immunoprecipitation and luciferase reporter assays were used to determine the interacting molecules and the activity of the enzyme. An in vivo study was carried out in GC xenograft mice. Cell culture-based assays were represented as mean ± SD. ANOVA tests were used to assess differences across groups. All pairwise comparisons between tumor weights among treatment groups were made using the Tukey-Kramer method for multiple comparison adjustment to control experimental-wise type I error rates. Significance was set at P < 0.05.
RESULTS
PCI-24781 significantly reduced the growth of the GC cells, enhanced cell apoptosis and suppressed clonogenicity, and these effects synergized with the effects of CDDP. PCI-24781 modulated the cell cycle and significantly reduced the expression of RAD51, which is related to homologous recombination. Depletion of RAD51 augmented the biological functions of PCI-24781, CDDP and the combination treatment, whereas overexpressing RAD51 had the opposite effects. Increased binding of the transcription suppressor E2F4 on the RAD51 promoter appeared to play a major role in these processes. Furthermore, significant suppression of tumor growth and weight in vivo was obtained following PCI-24781 treatment, which synergized with the anticancer effect of CDDP.
CONCLUSION
These data suggest that RAD51 potentiates the synergistic effects of chemotherapy with PCI-24781 and CDDP on GC.
Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzofurans; Binding Sites; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dose-Response Relationship, Drug; Drug Synergism; E2F4 Transcription Factor; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Mice, SCID; Promoter Regions, Genetic; Rad51 Recombinase; Signal Transduction; Stomach Neoplasms; Time Factors; Transfection; Tumor Burden; Xenograft Model Antitumor Assays
PubMed: 25110436
DOI: 10.3748/wjg.v20.i29.10094 -
PloS One 2013Hypoxia inducible factor (HIF) is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration....
Hypoxia inducible factor (HIF) is important in cancer, as it regulates various oncogenic genes as well as genes involved in cell survival, proliferation, and migration. Elevated HIF-1 protein promotes a more aggressive tumor phenotype, and greater HIF-1 expression has been demonstrated to correlate with poorer prognosis, increased risk of metastasis and increased mortality. Recent reports suggest that HIF-1 activates autophagy, a lysosomal degradation pathway which may promote tumor cell survival. We show here that HIF-1α expression is constitutively active in multiple diffuse large B cell lymphoma (DLBCL) cell lines under normoxia and it is regulated by the PI3K/AKT pathway. PCI-24781, a pan histone deacetylase inhibitor (HDACI), enhanced accumulation of HIF-1α and induced autophagy initially, while extended incubation with the drug resulted in inhibition of HIF-1α. We tested the hypothesis that PCI-24781- induced autophagy is mediated by HIF-1α and that inhibition of HIF-1α in these cells results in attenuation of autophagy and decreased survival. We also provide evidence that autophagy serves as a survival pathway in DLBCL cells treated with PCI-24781 which suggests that the use of autophagy inhibitors such as chloroquine or 3-methyl adenine in combination with PCI-24781 may enhance apoptosis in lymphoma cells.
Topics: AMP-Activated Protein Kinases; Autophagy; Benzofurans; Cell Survival; Drug Synergism; Enzyme Activation; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Hypoxia-Inducible Factor 1, alpha Subunit; Lymphoma, Large B-Cell, Diffuse; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction
PubMed: 24312289
DOI: 10.1371/journal.pone.0081333 -
PloS One 2013Neuroblastoma is the second most common solid tumor diagnosed during infancy. The survival rate among children with high-risk neuroblastoma is less than 40%,...
Neuroblastoma is the second most common solid tumor diagnosed during infancy. The survival rate among children with high-risk neuroblastoma is less than 40%, highlighting the urgent needs for new treatment strategies. PCI-24781 is a novel hydroxamic acid-based histone deacetylase (HDAC) inhibitor that has high efficacy and safety for cancer treatment. However, the underlying mechanisms of PCI-24781 are not clearly elucidated in neuroblastoma cells. In the present study, we demonstrated that PCI-24781 treatment significantly inhibited tumor growth at very low doses in neuroblastoma cells SK-N-DZ, not in normal cell line HS-68. However, PCI-24781 caused the accumulation of acetylated histone H3 both in SK-N-DZ and HS-68 cell line. Treatment of SK-N-DZ with PCI-24781 also induced cell cycle arrest in G2/M phase and activated apoptosis signaling pathways via the up-regulation of DR4, p21, p53 and caspase 3. Further proteomic analysis revealed differential protein expression profiles between non-treated and PCI-24781 treated SK-N-DZ cells. Totally 42 differentially expressed proteins were identified by MALDI-TOF MS system. Western blotting confirmed the expression level of five candidate proteins including prohibitin, hHR23a, RuvBL2, TRAP1 and PDCD6IP. Selective knockdown of RuvBL2 rescued cells from PCI-24781-induced cell death, implying that RuvBL2 might play an important role in anti-tumor activity of PCI-24781 in SK-N-DZ cells. The present results provide a new insight into the potential mechanism of PCI-24781 in SK-N-DZ cell line.
Topics: ATPases Associated with Diverse Cellular Activities; Acetylation; Apoptosis; Benzofurans; Blotting, Western; Carrier Proteins; Cell Line, Tumor; DNA Helicases; G2 Phase Cell Cycle Checkpoints; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Male; Mitosis; Models, Biological; Neoplasm Proteins; Neuroblastoma; Proteomics; Reproducibility of Results; Signal Transduction
PubMed: 23977108
DOI: 10.1371/journal.pone.0071663 -
PloS One 2013MSH3 is a DNA mismatch repair (MMR) gene that undergoes frequent somatic mutation in colorectal cancers (CRCs) with MMR deficiency. MSH3, together with MSH2, forms the...
BACKGROUND
MSH3 is a DNA mismatch repair (MMR) gene that undergoes frequent somatic mutation in colorectal cancers (CRCs) with MMR deficiency. MSH3, together with MSH2, forms the MutSβ heteroduplex that interacts with interstrand cross-links induced by drugs such as cisplatin. To date, the impact of MSH3 on chemosensitivity is unknown.
METHODS
We utilized isogenic HCT116 (MLH1-/MSH3-) cells where MLH1 is restored by transfer of chromosome 3 (HCT116+ch3) and also MSH3 by chromosome 5 (HCT116+3+5). We generated HCT116+3+5, SW480 (MLH1+/MSH3+) and SW48 (MLH1-/MSH3+) cells with shRNA knockdown of MSH3. Cells were treated with 5-fluorouracil (5-FU), SN-38, oxaliplatin, or the histone deacetylase (HDAC) inhibitor PCI-24781 and cell viability, clonogenic survival, DNA damage and apoptosis were analyzed.
RESULTS
MSH3-deficient vs proficient CRC cells showed increased sensitivity to the irinotecan metabolite SN-38 and to oxaliplatin, but not 5-FU, as shown in assays for apoptosis and clonogenic survival. In contrast, suppression of MLH1 attenuated the cytotoxic effect of 5-FU, but did not alter sensitivity to SN-38 or oxaliplatin. The impact of MSH3 knockdown on chemosensitivity to SN-38 and oxaliplatin was maintained independent of MLH1 status. In MSH3-deficient vs proficient cells, SN-38 and oxaliplatin induced higher levels of phosphorylated histone H2AX and Chk2, and similar results were found in MLH1-proficient SW480 cells. MSH3-deficient vs proficient cells showed increased 53BP1 nuclear foci after irradiation, suggesting that MSH3 can regulate DNA double strand break (DSB) repair. We then utilized PCI-24781 that interferes with homologous recombination (HR) indicated by a reduction in Rad51 expression. The addition of PCI-24781 to oxaliplatin enhanced cytotoxicity to a greater extent compared to either drug alone.
CONCLUSION
MSH3 status can regulate the DNA damage response and extent of apoptosis induced by chemotherapy. The ability of MSH3 to regulate chemosensitivity was independent of MLH1 status. PCI-24781-mediated impairment of HR enhanced oxaliplatin sensitivity, suggesting that reduced DSB repair capacity may be contributory.
Topics: Adaptor Proteins, Signal Transducing; Antineoplastic Agents; Benzofurans; Camptothecin; Cell Death; Cell Nucleus; Cell Survival; Colonic Neoplasms; DNA Damage; DNA Mismatch Repair; DNA-Binding Proteins; Drug Screening Assays, Antitumor; Fluorescent Antibody Technique; Fluorouracil; Gene Knockdown Techniques; HCT116 Cells; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Irinotecan; MutL Protein Homolog 1; MutS Homolog 3 Protein; Nuclear Proteins; Organoplatinum Compounds; Oxaliplatin; Rad51 Recombinase
PubMed: 23724141
DOI: 10.1371/journal.pone.0065369 -
PloS One 2013Hormonal therapy resistance remains a considerable barrier in the treatment of breast cancer. Activation of the Akt-PI3K-mTOR pathway plays an important role in hormonal...
Hormonal therapy resistance remains a considerable barrier in the treatment of breast cancer. Activation of the Akt-PI3K-mTOR pathway plays an important role in hormonal therapy resistance. Our recent preclinical and clinical studies showed that the addition of a histone deacetylase inhibitor re-sensitized hormonal therapy resistant breast cancer to tamoxifen. As histone deacetylases are key regulators of Akt, we evaluated the effect of combined treatment with the histone deacetylase inhibitor PCI-24781 and tamoxifen on Akt in breast cancer cells. We demonstrate that while both histone deacetylase and estrogen receptor inhibition down regulate AKT mRNA and protein, their concerted effort results in down regulation of AKT activity with induction of cell death. Histone deacetylase inhibition exerts its effect on AKT mRNA through an estrogen receptor-dependent mechanism, primarily down regulating the most abundant isoform AKT1. Although siRNA depletion of AKT modestly induces cell death, when combined with an anti-estrogen, cytotoxicity is significantly enhanced. Thus, histone deacetylase regulation of AKT mRNA is a key mediator of this therapeutic combination and may represent a novel biomarker for predicting response to this regimen.
Topics: Apoptosis; Benzofurans; Breast Neoplasms; Cell Line, Tumor; Endoplasmic Reticulum; Enzyme Activation; Female; Gene Expression Regulation, Neoplastic; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Mitochondria; Proto-Oncogene Proteins c-akt; RNA, Messenger; Receptors, Estrogen; Selective Estrogen Receptor Modulators; Tamoxifen
PubMed: 23874830
DOI: 10.1371/journal.pone.0068973 -
Anticancer Research Apr 2011The antitumor activity of histone deacetylase inhibitors (HDACI) on multidrug-resistant sarcoma cell lines has not been previously described. Treatment of...
The antitumor activity of histone deacetylase inhibitors (HDACI) on multidrug-resistant sarcoma cell lines has not been previously described. Treatment of multidrug-resistant sarcoma cell lines with HDACI PCI-24781 resulted in dose-dependent accumulation of acetylated histone, p21 and poly(ADP-ribose)polymerase (PARP) cleavage products. Growth of these cell lines was inhibited by PCI-24781 at IC(50) of 0.43 to 2.7. When we looked for synergy of PCI-24781 with chemotherapeutic agents, we found that PCI-24781 reverses drug resistance in all four multidrug-resistant sarcoma cell lines and synergizes with chemotherapeutic agents to enhance caspase-3/-7 activity. Expression of RAD51 (a marker for DNA double-strand break repair) was inhibited and the expression of GADD45α (a marker for growth arrest and DNA-damage) was induced by PCI-24781 in multidrug-resistant sarcoma cell lines. In conclusion, HDACI PCI-24781 synergizes with chemotherapeutic drugs to induce apoptosis and reverses drug resistance in multidrug-resistant sarcoma cell lines.
Topics: ATP Binding Cassette Transporter, Subfamily B; Antineoplastic Agents; Apoptosis; Benzofurans; Blotting, Western; Caspases; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Nuclear Proteins; Poly(ADP-ribose) Polymerases; Sarcoma; ATP-Binding Cassette Sub-Family B Member 4
PubMed: 21508354
DOI: No ID Found -
Proceedings of the National Academy of... Dec 2007Histone deacetylase (HDAC) inhibitors such as the phenyl hydroxamic acid PCI-24781 have emerged recently as a class of therapeutic agents for the treatment of cancer....
Histone deacetylase (HDAC) inhibitors such as the phenyl hydroxamic acid PCI-24781 have emerged recently as a class of therapeutic agents for the treatment of cancer. Recent data showing synergy of HDAC inhibitors with ionizing radiation and other DNA-damaging agents have suggested that HDAC inhibitors may act, in part, by inhibiting DNA repair. Here we present evidence that HDAC enzymes are important for homologous recombinational repair of DNA double-strand breaks. Combination studies of PCI-24781 with the poly(ADP-ribose) polymerase inhibitor PJ34, an agent thought to produce lesions repaired by homologous recombination (HR), resulted in a synergistic effect on apoptosis. Immunofluorescence analysis demonstrated that HDAC inhibition caused a complete inhibition of subnuclear repair foci in response to ionizing radiation. Mechanistic investigations revealed that inhibition of HDAC enzymes by PCI-24781 led to a significant reduction in the transcription of genes specifically associated with HR, including RAD51. RAD51 protein levels were significantly decreased after 24 h of drug exposure both in vitro and in vivo. Consistent with inhibition of HR, treatment with PCI-24781 resulted in a decreased ability to perform homology directed repair of I-SceI-induced chromosome breaks in transfected CHO cells. In addition, an enhancement of cell killing was observed in Ku mutant cells lacking functional nonhomologous end joining compared with WT cells. Together these results demonstrate that HDAC enzymes are critically important to enable functional HR by controlling the expression of HR-related genes and promoting the proper assembly of HR-directed subnuclear foci.
Topics: Animals; Apoptosis; Benzofurans; Cell Line, Tumor; DNA Repair; Drug Synergism; Enzyme Inhibitors; Gene Expression Regulation; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Phenanthrenes; Poly(ADP-ribose) Polymerase Inhibitors; Rad51 Recombinase; Radiation Tolerance; Radiation-Sensitizing Agents; Recombination, Genetic; Transcription, Genetic; Up-Regulation
PubMed: 18042714
DOI: 10.1073/pnas.0707828104