Modulation of chemically-induced hepatocarcinogenesis by indole-3-carbinol : mechanisms and species comparison

There is plenty of evidence from epidemiology studies supporting a link between certain components in the human diet and cancer incidence. It is estimated that 3-4 million annual cases of cancer could be prevented worldwide just by changing dietary habits. In parts of the world where vegetables and fruits constitute a large part of the diet, certain cancer incidences are markedly lower compared to Western countries. In particular, consumption of cruciferous vegetables is negatively associated with occurrence of certain cancers. One of the compounds from crucifers that is implicated in chemoprevention, is indole-3-carbinol(I3C), documented to inhibit tumor formation in several tissues in rodents, including the mammary tissue. I3C and is currently being evaluated in several clinical trials as a chemopreventive agent against breast cancer in humans. There are, however, some legitimate concerns regarding the use of Pure I3C since, depending upon conditions of administration, I3C can act as a promoter of hepatocarcinogenesis. Evidence is presented here that dietary I3C can promote and/or enhance liver tumor formation in rainbow trout (supporting earlier reports in literature) and the C57BL/6J mouse (enhancement in short-term pre-initiation exposure through lactational transfer, inhibition in a long-term post-initiation feeding study). I3C is also reported to promote in the rat liver model. A major concern associated with dietary I3C supplementation relates to its estrogenic effects as seen in trout and also its ability to induce certain cytochrome P-450s involved in procarcinogen activation. Biological effects of I3C are attributed to its acid condensation products. It was observed in this study that I3C acts through different mechanisms, including the Ah receptor-mediated and estrogenic pathways. Understanding of the role of I3C derivatives in beneficial and/or hazardous effects resulting from dietary exposure will be crucial in evaluating the promise of I3C as a chemoprevention agent. Questions pertaining to the risk/benefit of the use of dietary I3C supplementation for preventing estrogen-related diseases, without increasing the risk of promotion of hepatocarcinogenesis in humans, may depend on whether the mechanism(s) of action of I3C derivatives in humans is more like the adult mouse or the neonatal mouse, rat and trout

Dose-escalation study of a second-generation non-ansamycin HSP90 inhibitor, onalespib (AT13387), in combination with imatinib in patients with metastatic gastrointestinal stromal tumour

AbstractBackgroundGastrointestinal stromal tumours (GIST) treated with the tyrosine kinase inhibitor (TKI) imatinib can become resistant when additional mutations in the receptor tyrosine kinases KIT or PDGFRA block imatinib activity. Mutated KIT requires the molecular chaperone heat-shock protein 90 (HSP90) to maintain stability and activity. Onalespib (AT13387) is a potent non-ansamycin HSP90 inhibitor. We hypothesised that the combination of onalespib and imatinib may be safe and effective in managing TKI-resistant GIST.Patients and methodsIn this dose-escalation study, we evaluated the safety and efficacy of combination once-weekly intravenous onalespib for 3 weeks and daily oral imatinib in 28-d cycles. Twenty-six patients with TKI-resistant GIST were enrolled into four sequential dose cohorts of onalespib (dose range, 150–220 mg/m2) and imatinib 400 mg. The relationship between tumour mutational status (KIT/PDGFRA) and efficacy of treatment was explored.ResultsCommon onalespib-related adverse events were diarrhoea (58%), nausea (50%), injection site events (46%), vomiting (39%), fatigue (27%), and muscle spasms (23%). Overall, 81% of patients reported more than one onalespib-related gastrointestinal disorder. Nine patients (35%) had a best response of stable disease, including two patients who had KIT mutations known to be associated with resistance to imatinib and sunitinib. Disease control at 4 months was achieved in five patients (19%), and median progression-free survival was 112 d (95% confidence interval 43–165). One patient with PDGFRA-mutant GIST had a partial response for more than 376 d.ConclusionThe combination of onalespib plus imatinib was well tolerated but exhibited limited antitumour activity as dosed in this TKI-resistant GIST patient population.Trial registration ID: clinicaltrials.gov: NCT0129420

A Randomized Phase II Trial of Epigenetic Priming with Guadecitabine and Carboplatin in Platinum-resistant, Recurrent Ovarian Cancer.

PURPOSE: Platinum resistance in ovarian cancer is associated with epigenetic modifications. Hypomethylating agents (HMA) have been studied as carboplatin resensitizing agents in ovarian cancer. This randomized phase II trial compared guadecitabine, a second-generation HMA, and carboplatin (G+C) against second-line chemotherapy in women with measurable or detectable platinum-resistant ovarian cancer. PATIENTS AND METHODS: Patients received either G+C (guadecitabine 30 mg/m2 s.c. once-daily for 5 days and carboplatin) or treatment of choice (TC; topotecan, pegylated liposomal doxorubicin, paclitaxel, or gemcitabine) in 28-day cycles until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were RECIST v1.1 and CA-125 response rate, 6-month PFS, and overall survival (OS). RESULTS: Of 100 patients treated, 51 received G+C and 49 received TC, of which 27 crossed over to G+C. The study did not meet its primary endpoint as the median PFS was not statistically different between arms (16.3 weeks vs. 9.1 weeks in the G+C and TC groups, respectively; P = 0.07). However, the 6-month PFS rate was significantly higher in the G+C group (37% vs. 11% in TC group; P = 0.003). The incidence of grade 3 or higher toxicity was similar in G+C and TC groups (51% and 49%, respectively), with neutropenia and leukopenia being more frequent in the G+C group. CONCLUSIONS: Although this trial did not show superiority for PFS of G+C versus TC, the 6-month PFS increased in G+C treated patients. Further refinement of this strategy should focus on identification of predictive markers for patient selection

Development, validation, and clinical application of a high-performance liquid chromatography-tandem mass spectrometry assay for the quantification of total intracellular β-decitabine nucleotides and genomic DNA incorporated β-decitabine and 5-methyl-2'-deoxycytidine

DNA hypermethylation is an epigenetic event that is commonly found in malignant cells and is used as a therapeutic target for β-decitabine (β-DEC) containing hypomethylating agents (eg Dacogen® and guadecitabine). β-DEC requires cellular uptake and intracellular metabolic activation to β-DEC triphosphate before it can get incorporated into the DNA. Once incorporated in the DNA, β-DEC can exert its hypomethylating effect by trapping DNA methyltransferases (DNMTs), resulting in reduced 5-methyl-2'-deoxycytidine (5mdC) DNA content. β-DEC DNA incorporation and its effect on DNA methylation, however, have not yet been investigated in patients treated with β-DEC containing therapies. For this reason, we developed and validated a sensitive and selective LC-MS/MS method to determine total intracellular β-DEC nucleotide (β-DEC-XP) concentrations, as well as to quantify β-DEC and 5mdC DNA incorporation relative to 2'-deoxycytidine (2dC) DNA content. The assay was successfully validated according to FDA and EMA guidelines in a linear range from 0.5 to 100 ng/mL (β-DEC), 50 to 10,000 ng/mL (2dC), and 5 to 1,000 ng/mL (5mdC) in peripheral blood mononuclear cell (PBMC) lysate. An additional calibrator at a concentration of 0.1 ng/mL was added for β-DEC to serve as a limit of detection (LOD). Clinical applicability of the method was demonstrated in patients treated with guadecitabine. Our data support the use of the validated LC-MS/MS method to further explore the intracellular pharmacokinetics in patients treated with β-DEC containing hypomethylating agents

Development, validation, and clinical application of a high-performance liquid chromatography-tandem mass spectrometry assay for the quantification of total intracellular β-decitabine nucleotides and genomic DNA incorporated β-decitabine and 5-methyl-2'-deoxycytidine

DNA hypermethylation is an epigenetic event that is commonly found in malignant cells and is used as a therapeutic target for β-decitabine (β-DEC) containing hypomethylating agents (eg Dacogen® and guadecitabine). β-DEC requires cellular uptake and intracellular metabolic activation to β-DEC triphosphate before it can get incorporated into the DNA. Once incorporated in the DNA, β-DEC can exert its hypomethylating effect by trapping DNA methyltransferases (DNMTs), resulting in reduced 5-methyl-2'-deoxycytidine (5mdC) DNA content. β-DEC DNA incorporation and its effect on DNA methylation, however, have not yet been investigated in patients treated with β-DEC containing therapies. For this reason, we developed and validated a sensitive and selective LC-MS/MS method to determine total intracellular β-DEC nucleotide (β-DEC-XP) concentrations, as well as to quantify β-DEC and 5mdC DNA incorporation relative to 2'-deoxycytidine (2dC) DNA content. The assay was successfully validated according to FDA and EMA guidelines in a linear range from 0.5 to 100 ng/mL (β-DEC), 50 to 10,000 ng/mL (2dC), and 5 to 1,000 ng/mL (5mdC) in peripheral blood mononuclear cell (PBMC) lysate. An additional calibrator at a concentration of 0.1 ng/mL was added for β-DEC to serve as a limit of detection (LOD). Clinical applicability of the method was demonstrated in patients treated with guadecitabine. Our data support the use of the validated LC-MS/MS method to further explore the intracellular pharmacokinetics in patients treated with β-DEC containing hypomethylating agents

In Vitro Metabolism, Permeability, and Efflux of Bazedoxifene in Humans

ABSTRACT: Bazedoxifene (BZA) acetate, a novel estrogen receptor modulator being developed for the prevention and treatment of postmenopausal osteoporosis, undergoes extensive metabolism in women after oral administration. In this study, the in vitro metabolism of [ 14 C]BZA was determined in human hepatocytes and hepatic and intestinal microsomes, and the UDP glucuronosyltransferase (UGT) isozymes involved in the glucuronidation of BZA were identified. In addition, BZA was evaluated for its potential as a substrate of P-glycoprotein (P-gp) transporter in Caco-2 cell monolayers. BZA was metabolized to two monoglucuronides, BZA-4-glucuronide and BZA-5-glucuronide, in hepatocytes and in liver and intestinal microsomes including jejunum, duodenum, and ileum. Both BZA-4-glucuronide and BZA-5-glucuronide were major metabolites in the intestinal microsomes, whereas BZA-4-glucuronide was the predominant metabolite in liver microsomes and hepatocytes. The kinetic parameters of BZA-4-glucuronide formation were determined in liver, duodenum, and jejunum microsomes and with UGT1A1, 1A8, and 1A10, the most active UGT isoforms involved in the glucuronidation of BZA, whereas those of BZA-5-glucuronide were determined with all the enzyme systems except in liver microsomes and in UGT1A1 because the formation of the BZA-5-glucuronide was too low. K m values in liver, duodenum, and jejunum microsomes and UGT1A1, 1A8, and 1A10, were similar and ranged from 5.1 to 33.1 M for BZA-4-glucuronide formation and from 2.5 to 11.1 M for BZA-5-glucuronide formation. V max values ranged from 0.8 to 2.9 nmol/(min ⅐ mg) protein for BZA-4-glucuronide and from 0.1 to 1.2 nmol/(min ⅐ mg) protein for BZA-5-glucuronide. In Caco-2 cells, BZA appeared to be a P-gp substrate

Development and validation of LC-MS/MS methods for the quantification of the novel anticancer agent guadecitabine and its active metabolite β‑decitabine in human plasma, whole blood and urine

Guadecitabine (SGI-110), a dinucleotide of β‑decitabine and deoxyguanosine, is currently being evaluated in phase II/III clinical trials for the treatment of hematological malignancies and solid tumors. This article describes the development and validation of bioanalytical assays to quantify guadecitabine and its active metabolite β‑decitabine in human plasma, whole blood and urine using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Since β‑decitabine is rapidly metabolized further by cytidine deaminase, plasma and whole blood samples were kept on ice-water after collection and stabilized with tetrahydrouridine (THU) directly upon sample collection. Sample preparation consisted of protein precipitation for plasma and whole blood and dilution for urine samples and was further optimized for each matrix and analyte separately. Final extracts were injected onto a C6-phenyl column for guadecitabine analysis, or a Nova-Pak Silica column for β‑decitabine analysis. Gradient elution was applied for both analytes using the same eluents for each assay and detection was performed on triple quadrupole mass spectrometers operating in the positive ion mode (Sciex QTRAP 5500 and QTRAP 6500). The assay for guadecitabine was linear over a range of 1.0-200 ng/mL (plasma, whole blood) and 10-2000 ng/mL (urine). For β‑decitabine the assay was linear over a range of 0.5-100 ng/mL (plasma, whole blood) and 5-1000 ng/mL (urine). The presented methods were successfully validated according to the latest FDA and EMA guidelines for bioanalytical method validation and applied in a guadecitabine clinical mass balance trial in patients with advanced cancer

Development and validation of LC-MS/MS methods for the quantification of the novel anticancer agent guadecitabine and its active metabolite β‑decitabine in human plasma, whole blood and urine

Guadecitabine (SGI-110), a dinucleotide of β‑decitabine and deoxyguanosine, is currently being evaluated in phase II/III clinical trials for the treatment of hematological malignancies and solid tumors. This article describes the development and validation of bioanalytical assays to quantify guadecitabine and its active metabolite β‑decitabine in human plasma, whole blood and urine using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Since β‑decitabine is rapidly metabolized further by cytidine deaminase, plasma and whole blood samples were kept on ice-water after collection and stabilized with tetrahydrouridine (THU) directly upon sample collection. Sample preparation consisted of protein precipitation for plasma and whole blood and dilution for urine samples and was further optimized for each matrix and analyte separately. Final extracts were injected onto a C6-phenyl column for guadecitabine analysis, or a Nova-Pak Silica column for β‑decitabine analysis. Gradient elution was applied for both analytes using the same eluents for each assay and detection was performed on triple quadrupole mass spectrometers operating in the positive ion mode (Sciex QTRAP 5500 and QTRAP 6500). The assay for guadecitabine was linear over a range of 1.0-200 ng/mL (plasma, whole blood) and 10-2000 ng/mL (urine). For β‑decitabine the assay was linear over a range of 0.5-100 ng/mL (plasma, whole blood) and 5-1000 ng/mL (urine). The presented methods were successfully validated according to the latest FDA and EMA guidelines for bioanalytical method validation and applied in a guadecitabine clinical mass balance trial in patients with advanced cancer