Coumarin-Based Aldo-Keto Reductase Family 1C (AKR1C) 2 and 3 Inhibitors.

A series of 7-substituted coumarin derivatives have been characterized as pan-aldo-keto reductase family 1C (AKR1C) inhibitors. The AKR1C family of enzymes are overexpressed in numerous cancers where they are involved in drug resistance development. 7-hydroxy coumarin ethyl esters and their corresponding amides have high potency for AKR1C3 and AKR1C2 inhibition.

Phase I trial of intravenous fenretinide (4-HPR) plus safingol in advanced malignancies.

Purpose: Fenretinide (4-HPR) is a synthetic retinoid that induces cytotoxicity through dihydroceramide production. Safingol, a stereochemical-variant dihydroceramide precursor, exhibits synergistic effects when administered with fenretinide in preclinical studies. We conducted a phase 1 dose-escalation clinical trial of this combination.

DNA-PKcs as an upstream mediator of OCT4-induced MYC activation in small cell lung cancer.

Small cell lung cancer (SCLC) is a neuroendocrine tumor noted for the rapid development of both metastases and resistance to chemotherapy. High mutation burden, ubiquitous loss of TP53 and RB1, and a mutually exclusive amplification of MYC gene family members contribute to genomic instability and make the development of new targeted agents a challenge. Previously, we reported a novel OCT4-induced MYC transcriptional activation pathway involving c-MYC, pOCT4, and MAPKAPK2 in progressive neuroblastoma, also a neuroendocrine tumor.

A phase I study of intravenous fenretinide (4-HPR) for patients with malignant solid tumors.

Background: Fenretinide is a synthetic retinoid that can induce cytotoxicity by several mechanisms. Achieving effective systemic exposure with oral formulations has been challenging. An intravenous lipid emulsion fenretinide formulation was developed to overcome this barrier.

Hydrophilic interaction liquid chromatography-tandem mass spectrometric approach for simultaneous determination of safingol and D-erythro-sphinganine in human plasma.

A simple and specific hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method was developed for the simultaneous determination of C18-L-threo-sphinganine (safingol, an anti-neoplastic in phase I trials) and its diastereomer, C18-D-erythro-sphinganine (sphinganine), in human plasma. Sample pretreatment involved a protein precipitation with methanol using 25 μL aliquots of plasma. Chromatographic separation of the diastereomers and C17-D-erythro-sphinganine, an internal standard, was achieved on a Xbridge HILIC (3.

Cytotoxicity and molecular activity of fenretinide and metabolites in T-cell lymphoid malignancy, neuroblastoma, and ovarian cancer cell lines in physiological hypoxia.

Objective: All-trans-N-(4-hydroxyphenyl)retinamide or fenretinide (4-HPR) acts by reactive oxygen species (ROS) and dihydroceramides (DHCers). In early-phase clinical trials 4-HPR has achieved complete responses in T-cell lymphomas (TCL) and neuroblastoma (NB) and signals of activity in ovarian cancer (OV). We defined the activity of 4-HPR metabolites in N-(4-methoxyphenyl)retinamide (MPR), 4-oxo-N-(4-hydroxyphenyl)retinamide (oxoHPR), and the 4-HPR isomer 13-cis-fenretinide (cis-HPR) in NB, OV, and TCL cell lines cultured in physiological hypoxia.

Phase I Study of Fenretinide Delivered Intravenously in Patients with Relapsed or Refractory Hematologic Malignancies: A California Cancer Consortium Trial.

A phase I study was conducted to determine the MTD, dose-limiting toxicities (DLT), and pharmacokinetics of fenretinide delivered as an intravenous emulsion in relapsed/refractory hematologic malignancies. Fenretinide (80-1,810 mg/m/day) was administered by continuous infusion on days 1 to 5, in 21-day cycles, using an accelerated titration design. Twenty-nine patients, treated with a median of three prior regimens (range, 1-7), were enrolled and received the test drug.

P450 inhibitor ketoconazole increased the intratumor drug levels and antitumor activity of fenretinide in human neuroblastoma xenograft models.

We previously reported that concurrent ketoconazole, an oral anti-fungal agent and P450 enzyme inhibitor, increased plasma levels of the cytotoxic retinoid, fenretinide (4-HPR) in mice. We have now determined the effects of concurrent ketoconazole on 4-HPR cytotoxic dose-response in four neuroblastoma (NB) cell lines in vitro and on 4-HPR activity against two cell line-derived, subcutaneous NB xenografts (CDX) and three patient-derived NB xenografts (PDX). Cytotoxicity in vitro was assessed by DIMSCAN assay.

Reactive Oxygen Species Mediates the Synergistic Activity of Fenretinide Combined with the Microtubule Inhibitor ABT-751 against Multidrug-Resistant Recurrent Neuroblastoma Xenografts.

ABT-751 is a colchicine-binding site microtubule inhibitor. Fenretinide (4-HPR) is a synthetic retinoid. Both agents have shown activity against neuroblastoma in laboratory models and clinical trials.

Probable fatal drug interaction between intravenous fenretinide, ceftriaxone, and acetaminophen: a case report from a New Approaches to Neuroblastoma (NANT) Phase I study.

Background: Patients with relapsed/refractory stage 4 high-risk neuroblastoma were enrolled on a phase I study (NANT2004-03) of intravenous fenretinide emulsion. Pharmacokinetic samples were collected during and after the infusion, and the levels were measured using an HPLC system. A likely case of a fatal drug interaction between fenretinide, ceftriaxone, and acetaminophen is described, including the pharmacokinetics of fenretinide, laboratory data, and post-mortem autopsy in a pediatric neuroblastoma patient treated on this study.

C22:0- and C24:0-dihydroceramides confer mixed cytotoxicity in T-cell acute lymphoblastic leukemia cell lines.

We previously reported that fenretinide (4-HPR) was cytotoxic to acute lymphoblastic leukemia (ALL) cell lines in vitro in association with increased levels of de novo synthesized dihydroceramides, the immediate precursors of ceramides. However, the cytotoxic potentials of native dihydroceramides have not been defined. Therefore, we determined the cytotoxic effects of increasing dihydroceramide levels via de novo synthesis in T-cell ALL cell lines and whether such cytotoxicity was dependent on an absolute increase in total dihydroceramide mass versus an increase of certain specific dihydroceramides.

Phase I trial of fenretinide delivered orally in a novel organized lipid complex in patients with relapsed/refractory neuroblastoma: a report from the New Approaches to Neuroblastoma Therapy (NANT) consortium.

Background: A phase I study was conducted to determine the maximum-tolerated dose, dose-limiting toxicities (DLTs), and pharmacokinetics of fenretinide (4-HPR) delivered in an oral powderized lipid complex (LXS) in patients with relapsed/refractory neuroblastoma.

Procedure: 4-HPR/LXS powder (352-2,210 mg/m(2) /day) was administered on Days 0-6, in 21-day courses, by standard 3 + 3 design.

Results: Thirty-two patients (median age = 8 years, range 3-27 years) enrolled with 30 evaluable for dose escalation.

Fenretinide sensitizes multidrug-resistant human neuroblastoma cells to antibody-independent and ch14.18-mediated NK cell cytotoxicity.

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Combining passive immunotherapy with an antibody to the disialoganglioside GD2 (ch14.18/SP2/0) and cytokines with 13-cis-retinoic acid for post-myeloablative maintenance therapy increased survival in high-risk NB, but the overall prognosis for these children is still in need of improvement.

Phase I trial of fenretinide lym-x-sorb oral powder in adults with solid tumors and lymphomas.

Background: The synthetic retinoid fenretinide (N-(4-hydroxyphenyl)retinamide, 4-HPR) has shown promising anticancer activity in preclinical studies, but its limited oral bioavailability has hindered clinical assessment. A novel lipid matrix, Lym-X-Sorb (LXS), was evaluated to improve fenretinide bioavailability and attain higher plasma concentrations.

Patients And Methods: Adults with refractory malignancies were administered fenretinide/LXS oral powder in 2 divided doses over 24 h for 7 consecutive days every 21 days in a standard phase I dose-escalation study with pharmacokinetic analysis.

Fenretinide metabolism in humans and mice: utilizing pharmacological modulation of its metabolic pathway to increase systemic exposure.

Background And Purpose: High plasma levels of fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] were associated with improved outcome in a phase II clinical trial. Low bioavailability of 4-HPR has been limiting its therapeutic applications. This study characterized metabolism of 4-HPR in humans and mice, and to explore the effects of ketoconazole, an inhibitor of CYP3A4, as a modulator to increase 4-HPR plasma levels in mice and to increase the low bioavailability of 4-HPR.

Toxicity assessment of molecularly targeted drugs incorporated into multiagent chemotherapy regimens for pediatric acute lymphocytic leukemia (ALL): review from an international consensus conference.

One of the challenges of incorporating molecularly targeted drugs into multi-agent chemotherapy (backbone) regimens is defining dose-limiting toxicities (DLTs) of the targeted agent against the background of toxicities of the backbone regimen. An international panel of 22 pediatric acute lymphocytic leukemia (ALL) experts addressed this issue (www.ALLNA.

Langerhans cell histiocytosis in a patient with stage 4 neuroblastoma receiving oral fenretinide.

Langerhans cell histiocytosis (LCH) has previously been reported in association with other malignancies. The pathogenesis of LCH and its relationship to other malignancies is poorly understood. We present a novel case of a child who developed an LCH bone lesion while receiving a Phase I protocol therapy with oral fenretinide/Lym-X-Sorb (4-HPR/LXS) powder for neuroblastoma.

Oral fenretinide in biochemically recurrent prostate cancer: a California cancer consortium phase II trial.

Background: Fenretinide is a synthetic retinoid that is cytotoxic to a variety of cancers. We conducted a phase II trial of oral fenretinide in patients with biochemically recurrent prostate cancer.

Patients And Methods: Eligible patients had histologically confirmed prostate cancer and a confirmed rising prostate-specific antigen (PSA) >or= 2 ng/mL following either radical prostatectomy and/or pelvic radiation therapy, without clinical or radiographic evidence of metastasis.

N-(4-Hydroxyphenyl)retinamide increases dihydroceramide and synergizes with dimethylsphingosine to enhance cancer cell killing.

Fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] is cytotoxic in many cancer cell types. Studies have shown that elevation of ceramide species plays a role in 4-HPR cytotoxicity. To determine 4-HPR activity in a multidrug-resistant cancer cell line as well as to study ceramide metabolism, MCF-7/AdrR cells (redesignated NCI/ADR-RES) were treated with 4-HPR and sphingolipids were analyzed.

N-(4-hydroxyphenyl) retinamide augments laser-induced choroidal neovascularization in mice.

Purpose: To evaluate the effect of N-4-hydroxyphenyl retinamide (4-HPR) on experimental laser-induced choroidal neovascularization (CNV) and on the expression and secretion of relevant growth factors by cultured human retinal pigment epithelial (RPE) cells.

Methods: CNV was induced by laser photocoagulation in C57BL/6 mice. 4-HPR (0.

Assessing combinations of cytotoxic agents using leukemia cell lines.

The mainstay of clinical anti-neoplastic chemotherapy is multi-agent combinations, most of which were developed empirically. To speed research and decrease costs, there is increasing interest in moving new drugs into clinical trials in potentially active combinations based upon pre-clinical testing data. Because testing drug combinations in animals is expensive and complex, defining drug combinations initially in cell culture assays is essential.

Improved oral delivery of N-(4-hydroxyphenyl)retinamide with a novel LYM-X-SORB organized lipid complex.

Purpose: Fenretinide [N-(4-hydroxyphenyl)retinamide (4-HPR)] is a cytotoxic retinoid that suffers from a wide interpatient variation in bioavailability when delivered orally in a corn oil capsule. The poor bioavailability of the capsule formulation may have limited responses in clinical trials, and the large capsules are not suitable for young children. To support the hypothesis that a novel organized lipid matrix, LYM-X-SORB, can increase the oral bioavailability of fenretinide, fenretinide in LYM-X-SORB matrix and in a powderized LYM-X-SORB formulation was delivered to mice.

Liquid chromatography method for quantifying D-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (D-threo-PPMP) in mouse plasma and liver.

A high-performance liquid chromatography (HPLC) method was developed to measure levels of d-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (d-threo-PPMP) in mouse plasma and liver. d-threo-PPMP was measured by HPLC with a Luna Pheny-Hexyl column (5 microm, 250 mm x 4.6 mm) employing UV detection at 210 nm using a mobile phase of potassium phosphate buffer (20mM, pH 3.

Evaluating response to antineoplastic drug combinations in tissue culture models.

The mainstay of clinical antineoplastic chemotherapy is multiagent combinations, most of which were developed empirically. Because of the desire to speed research and decrease costs, there is increasing interest in moving new drugs into clinical trials in potentially active combinations based on preclinical testing data. Different mathematical models have been proposed for evaluating drug interactions, which can be classified as synergistic (combinations demonstrating greater than the additive activity expected from each agent alone), additive, or antagonistic (drugs showing less activity in combination than expected from the sum of each agent alone).

Fenretinide cytotoxicity for Ewing's sarcoma and primitive neuroectodermal tumor cell lines is decreased by hypoxia and synergistically enhanced by ceramide modulators.

Patients with disseminated Ewing's family of tumors (ESFT) often experience drug-resistant relapse. We hypothesize that targeting minimal residual disease with the cytotoxic retinoid N-(4-hydroxyphenyl) retinamide (4-HPR; fenretinide) may decrease relapse. We determined the following: (a) 4-HPR cytotoxicity against 12 ESFT cell lines in vitro; (b) whether 4-HPR increased ceramide species (saturated and desaturated ceramides); (c) whether physiological hypoxia (2% O(2)) affected cytotoxicity, mitochondrial membrane potential (DeltaPsi(m)) change, or ceramide species or reactive oxygen species levels; (d) whether cytotoxicity was enhanced by l-threo-dihydrosphingosine (safingol); (e) whether physiological hypoxia increased acid ceramidase (AC) expression; and (f) the effect of the AC inhibitor N-oleoyl-ethanolamine (NOE) on cytotoxicity and ceramide species.