Aurora Gonzalez-Fierro

Histone acetylation and histone deacetylase activity of magnesium valproate in tumor and peripheral blood of patients with cervical cancer. A phase I study

BackgroundThe development of cancer has been associated with epigenetic alterations such as aberrant histone deacetylase (HDAC) activity. It was recently reported that valproic acid is an effective inhibitor of histone deacetylases and as such induces tumor cell differentiation, apoptosis, or growth arrest.MethodsTwelve newly diagnosed patients with cervical cancer were treated with magnesium valproate after a baseline tumor biopsy and blood sampling at the following dose levels (four patients each): 20 mg/kg; 30 mg/kg, or 40 mg/kg for 5 days via oral route. At day 6, tumor and blood sampling were repeated and the study protocol ended. Tumor acetylation of H3 and H4 histones and HDAC activity were evaluated by Western blot and colorimetric HDAC assay respectively. Blood levels of valproic acid were determined at day 6 once the steady-state was reached. Toxicity of treatment was evaluated at the end of study period.ResultsAll patients completed the study medication. Mean daily dose for all patients was 1,890 mg. Corresponding means for the doses 20-, 30-, and 40-mg/kg were 1245, 2000, and 2425 mg, respectively. Depressed level of consciousness grade 2 was registered in nine patients. Ten patients were evaluated for H3 and H4 acetylation and HDAC activity. After treatment, we observed hyperacetylation of H3 and H4 in the tumors of nine and seven patients, respectively, whereas six patients demonstrated hyperacetylation of both histones. Serum levels of valproic acid ranged from 73.6–170.49 μg/mL. Tumor deacetylase activity decreased in eight patients (80%), whereas two had either no change or a mild increase. There was a statistically significant difference between pre and post-treatment values of HDAC activity (mean, 0.36 vs. 0.21, two-tailed t test p < 0.0264). There was no correlation between H3 and H4 tumor hyperacetylation with serum levels of valproic acid.ConclusionMagnesium valproate at a dose between 20 and 40 mg/kg inhibits deacetylase activity and hyperacetylates histones in tumor tissues.

A Proof-Of-Principle Study of Epigenetic Therapy Added to Neoadjuvant Doxorubicin Cyclophosphamide for Locally Advanced Breast Cancer

Background Aberrant DNA methylation and histone deacetylation participate in cancer development and progression; hence, their reversal by inhibitors of DNA methylation and histone deacetylases (HDACs) is at present undergoing clinical testing in cancer therapy. As epigenetic alterations are common to breast cancer, in this proof-of-concept study demethylating hydralazine, plus the HDAC inhibitor magnesium valproate, were added to neoadjuvant doxorubicin and cyclophosphamide in locally advanced breast cancer to assess their safety and biological efficacy. Methodology This was a single-arm interventional trial on breast cancer patients (ClinicalTrials.gov Identifier: NCT00395655). After signing informed consent, patients were typed for acetylator phenotype and then treated with hydralazine at 182 mg for rapid-, or 83 mg for slow-acetylators, and magnesium valproate at 30 mg/kg, starting from day –7 until chemotherapy ended, the latter consisting of four cycles of doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 21 days. Core-needle biopsies were taken from primary breast tumors at diagnosis and at day 8 of treatment with hydralazine and valproate. Main Findings 16 patients were included and received treatment as planned. All were evaluated for clinical response and toxicity and 15 for pathological response. Treatment was well-tolerated. The most common toxicity was drowsiness grades 1–2. Five (31%) patients had clinical CR and eight (50%) PR for an ORR of 81%. No patient progressed. One of 15 operated patients (6.6%) had pathological CR and 70% had residual disease <3 cm. There was a statistically significant decrease in global 5mC content and HDAC activity. Hydralazine and magnesium valproate up- and down-regulated at least 3-fold, 1,091 and 89 genes, respectively. Conclusions Hydralazine and magnesium valproate produce DNA demethylation, HDAC inhibition, and gene reactivation in primary tumors. Doxorubicin and cyclophosphamide treatment is safe, well-tolerated, and appears to increase the efficacy of chemotherapy. A randomized phase III study is ongoing to support the efficacy of so-called epigenetic or transcriptional cancer therapy.

Antineoplastic effects of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in cancer cell lines

BackgroundAmong the epigenetic alterations occurring in cancer, DNA hypermethylation and histone hypoacetylation are the focus of intense research because their pharmacological inhibition has shown to produce antineoplastic activity in a variety of experimental models. The objective of this study was to evaluate the combined antineoplastic effect of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in a panel of cancer cell lines.ResultsHydralazine showed no growth inhibitory effect on cervical, colon, breast, sarcoma, glioma, and head & neck cancer cell lines when used alone. On the contrary, valproic acid showed a strong growth inhibitory effect that is potentiated by hydralazine in some cell lines. Individually, hydralazine and valproic acid displayed distinctive effects upon global gene over-expression but the number of genes over-expressed increased when cells were treated with the combination. Treatment of HeLa cells with hydralazine and valproic acid lead to an increase in the cytotoxicity of gemcitabine, cisplatin and adriamycin. A higher antitumor effect of adriamycin was observed in mice xenografted with human fibrosarcoma cells when the animals were co-treated with hydralazine and valproic acid.ConclusionHydralazine and valproic acid, two widely used drugs for cardiovascular and neurological conditions respectively have promising antineoplastic effects when used concurrently and may increase the antitumor efficacy of current cytotoxic agents.

Circulating nucleosomes and response to chemotherapy: An in vitro, in vivo and clinical study on cervical cancer patients

It is known that cell‐free DNA circulates in plasma/serum of patients with cancer and that part of this DNA circulates as nucleosomes that can be quantified by ELISA. We analyzed the effect of tumor and chemotherapy upon the levels of nucleosomes in vitro, in vivo and in cervical cancer patients. The levels of nucleosomes pre‐ and post‐treatment were correlated with response in 11 patients receiving chemotherapy. Nucleosomes were determined in nude mice treated with or without cisplatin and carrying tumors generated with HeLa cells, and in the cell lysate and supernatant of HeLa cells exposed to cisplatin in culture. In addition, nucleosomes were determined at different time points in patients and in rats receiving chemotherapy. Nucleosomes were higher in patients that controls (1,760 vs. 601, p = 0.0001). After 24 hr of treatment with oxaliplatin and gemcitabine, the levels decreased in 6 patients of whom 5 had response. Nucleosome levels differed between mice xenografted and not xenografted (765 vs. 378, p = 0.001) and between xenografted treated with or without cisplatin (650 vs. 765, p = 0.010), but not in tumor‐free animals treated and untreated with cisplatin (378 vs. 379, p = 0.99). In vitro, nucleosomes reached at peak 8 hr in cell lysates to decrease thereafter, whereas in supernatant, levels continued to increase up to 24 hr. Serial determination of nucleosomes in patients showed a rise within 6–12 hr and then a reduction to below the basal at 24 hr. In rats, nucleosomes had no major changes in those receiving oxaliplatin or the triple combination of cisplatin, gemcitabine and paclitaxel as compared to untreated controls. An overdose of this triple combination produced a transient elevation of almost 1,000 AU over the basal. Our results demonstrate that most of circulating nucleosomes originate from the tumor and that chemotherapy produces an early rise most likely due to tumor apoptosis and that nucleosomes are rapidly cleared from circulation. On the contrary, chemotherapy within the therapeutic range of doses has no effect on nucleosome levels in healthy mice and rats. This data suggests that the determination of circulating nucleosomes pre‐ and post‐treatment could be a useful test to predict response to chemotherapy in cancer patients.

Transcriptional changes induced by epigenetic therapy with hydralazine and magnesium valproate in cervical carcinoma

Aberrant DNA methylation and histone deacetylation participate in cancer development and progression; hence, their reversal by inhibitors of DNA methylation and histone deacetylases is a promising cancer therapy. Experimental data demonstrate that these inhibitors in combination do not only show synergy in antitumor effects but also in whole genome global expression. Ten pairs of pre- and post-treatment cervical tumor samples were analyzed by microarray analysis. Treatment for seven days with hydralazine and valproate (HV) in patients up-regulated 964 genes. The two pathways possessing the highest number of up-regulated genes comprised the ribosome protein and the oxidative phosphorylation pathways, followed by MAPK signaling, tight junction, adherens junction, actin cytoskeleton, cell cycle, focal adhesion, apoptosis, proteasome, Wnt signaling, and antigen processing and presentation pathways. Up-regulated genes by HV, clustered with down-regulated genes in untreated primary cervical carcinomas and were more alike as compared with up-regulated genes from untreated patients in terms of gene ontology. Increased acetylated p53 was also observed. Epigenetic therapy with HV leads to gene reactivation in primary tumors of cervical cancer patients as well as protein acetylation. A number of these reactivated genes have a definitive role as a tumor suppressors. The global expression pattern induced by HV suggests this therapy has an impact on pathways related to energy production which may promote apoptosis.

Expression of platelet derived growth factor family members and the potential role of imatinib mesylate for cervical cancer

BackgroundDespite significant achievements in the treatment of cervical cancer, it is still a deadly disease; hence newer therapeutical modalities are needed. Preliminary investigations suggest that platelet-derived growth factor (PDGF) might have a role in the development of cervical cancer, therefore it is important to determine whether this growth factor pathway is functional and its targeting with imatinib mesylate leads to growth inhibition of cervical cancer cells.ResultsPDGF receptors (PDGFR) and their ligands are frequently expressed in cervical cancer and the majority exhibited a combination of family members co-expression. A number of intronic and exonic variations but no known mutations in the coding sequence of the PDGFRα gene were found in cancer cell lines and primary tumors. Growth assays demonstrated that PDGFBB induces growth stimulation that can be blocked by imatinib and that this tyrosine kinase inhibitor on its own inhibits cell growth. These effects were associated with the phosphorylation status of the receptor.ConclusionThe PDGFR system may have a role in the pathogenesis of cervical cancer as their members are frequently expressed in this tumor and cervical cancer lines are growth inhibited by the PDGFR antagonist imatinib.

Hydralazine–valproate: a repositioned drug combination for the epigenetic therapy of cancer

Introduction: DNA methylation (DNMTi) and histone deacetylase inhibitors (HDACi) are in development for cancer therapy. So far, four epigenetic drugs are approved for myelodysplastic syndrome (MDS) and cutaneous T-cell lymphoma (CTCL). The combination of hydralazine-valproate (TRANSKRIP™) is being repositioned as an oral DNMT and HDAC inhibitor. Areas covered: Brief discussion on the current status of epigenetic drugs and studies published on the preclinical and clinical development of the hydralazine-valproate combination. Expert opinion: Drug repositioning is a strategy for prompt and cost-efficient drug discovery. There is evidence that combining DNMTi with HDACi would be more efficacious than administering each agent on its own. Hydralazine-valproate is safe when used alone or in combination with chemotherapy or chemoradiation. The fact that both drugs are orally administered is another advantage over current epigenetic drugs. This combination is promising but larger studies are needed. Among these, the randomized Phase III trials in advanced and in locally advanced cervical cancer combined with chemotherapy and cisplatin-radiation respectively, would eventually confirm its efficacy. Studies on MDS and CTCL would also eventually prove the efficacy of hydralazine valproate so that in the coming years hydralazine-valproate could have a role in cancer epigenetic therapy.

Dna methylation-independent reversion of gemcitabine resistance by hydralazine in cervical cancer cells

Background Down regulation of genes coding for nucleoside transporters and drug metabolism responsible for uptake and metabolic activation of the nucleoside gemcitabine is related with acquired tumor resistance against this agent. Hydralazine has been shown to reverse doxorubicin resistance in a model of breast cancer. Here we wanted to investigate whether epigenetic mechanisms are responsible for acquiring resistance to gemcitabine and if hydralazine could restore gemcitabine sensitivity in cervical cancer cells. Methodology/Principal Findings The cervical cancer cell line CaLo cell line was cultured in the presence of increasing concentrations of gemcitabine. Down-regulation of hENT1 & dCK genes was observed in the resistant cells (CaLoGR) which was not associated with promoter methylation. Treatment with hydralazine reversed gemcitabine resistance and led to hENT1 and dCK gene reactivation in a DNA promoter methylation-independent manner. No changes in HDAC total activity nor in H3 and H4 acetylation at these promoters were observed. ChIP analysis showed H3K9m2 at hENT1 and dCK gene promoters which correlated with hyper-expression of G9A histone methyltransferase at RNA and protein level in the resistant cells. Hydralazine inhibited G9A methyltransferase activity in vitro and depletion of the G9A gene by iRNA restored gemcitabine sensitivity. Conclusions/Significance Our results demonstrate that acquired gemcitabine resistance is associated with DNA promoter methylation-independent hENT1 and dCK gene down-regulation and hyper-expression of G9A methyltransferase. Hydralazine reverts gemcitabine resistance in cervical cancer cells via inhibition of G9A histone methyltransferase.

Epigenetic Therapy With Hydralazine and Magnesium Valproate Reverses Imatinib Resistance in Patients With Chronic Myeloid Leukemia

UNLABELLED The epigenetic drugs hydralazine and valproate were administered in a compassionate manner to 8 patients with chronic myeloid leukemia (CML) refractory to imatinib. Two patients had a complete hematologic response (25%),1 major cytogenetic response, 1 complete cytogenetic response (25% any cytogenetic response), and 3 (37.5%)stable disease. No grade 3 or 4 toxicity was observed. These results show the ability of epigenetic therapy to revert imatinib resistance. BACKGROUND Epigenetic alterations participate in the development of acquired resistance to imatinib, hence, the DNA methylation, and histone deacetylase inhibitors hydralazine and valproate, respectively, has the potential to overcome it. PATIENT AND METHODS A series of 8 patients with chronic myeloid leukemia (CML) refractory to imatinib mesylate with no access to second-generation tyrosine kinase inhibitors were treated with hydralazine and valproate in a compassionate manner. Clinical efficacy and safety of these drugs added to imatinib mesylate were evaluated. RESULTS Two patients were in the blast phase, 5 were in the accelerated phase, and 1 was in the chronic phase. All the patients continued with the same dose of imatinib that they had been receiving at the time of development of resistance, with a median dose of 600 mg daily (range, 400-800 mg). The median time from diagnosis of CML to the start of hydralazine and valproate was 53.6 months (range, 19-84 months). Two (25%) patients had a complete hematologic response, one (12.5%) had an major cytogenetic response, and one (12.5%) had a complete cytogenetic response. Three (37.5%) patients had stable disease, and only one (12.5%) patient failed to respond. At a median follow-up time of 18 months (range, 3-18 months), the median survival had not been reached, and the projected overall survival was 63%. All the patients had mild neurologic toxicity, including distal tremor and somnolence. No grade 3 or 4 toxicity was observed. CONCLUSIONS Our results suggest that the epigenetic drugs hydralazine and valproate revert the resistance to imatinib in patients with CML.

Pharmacokinetics of hydralazine, an antihypertensive and DNA-demethylating agent, using controlled-release formulations designed for use in dosing schedules based on the acetylator phenotype.

PURPOSE The antihypertensive hydralazine has recently been repositioned as DNA demethylating for the epigenetic therapy of cancer. As the acetylator phenotype is the key determinant of its plasma levels, the dose of hydralazine needs to be adjusted for the acetylation status of patients. METHODS The pharmacokinetics of orally administered hydralazine was evaluated in 26 healthy volunteers (13 slow and 13 fast acetylators) after a single dose of 182 mg administered as a controlled-release tablet. Plasma levels of hydralazine were analyzed in 85 cancer patients treated with this formulation at a dose of 83 mg/day and 182 mg/day for slow and fast acetylators, respectively. RESULTS The C(max) and t(max) of hydralazine for fast acetylators were 208.4 ± 56.9 SD ng/ml and 2.8 ± 2.5 h, respectively. The corresponding results for slow acetylators were 470.4 ± 162.8 ng/ml, and 4.4 ± 3.1 h. Healthy volunteers who were fast acetylators had no clinically significant changes in blood pressure and heart rate or any other side-effect, however, slow acetylators had transient episodes of headache, tachycardia and faintness. Among 85 cancer patients that received either 182 mg or 83 mg of hydralazine daily, according to their acetylator status, the mean concentrations of hydralazine in plasma were 239.1 ng/ml and 259.2 ng/ml for fast and slow acetylators, respectively. These differences were not significantly different, p = 0.3868. CONCLUSIONS The administration of dose-adjusted controlled-release hydralazine according to the acetylation status of cancer patients yields similar levels of hydralazine.