Free radical metabolism of raloxifene in human liver microsomes.

Xenobiotica

Drug Metabolism and Pharmacokinetics, Drug Safety Sciences, Janssen Research and Development, 1000 Route 202 South, Raritan, NJ 08869, USA.

Published: August 2012

Raloxifene was metabolized predominantly by CYP3A4 in human liver microsomes to a pair of carbon-carbon (RD1–2) and ether (RD3–4) linked homodimers in an nicotinamide adenine dinucleotide phosphate-dependent manner. The major homodimer formed by human liver microsomes (RD3) was different from the major homodimer formed by peroxidases (RD1). RD1, 3 and 4 were identified by both mass spectrometry (MS) and nuclear magnetic resonance (NMR) as symmetrical carbon-carbon (both carbon 7 from benzo[b]thiopen-6-ol) linked homodimer, asymmetrical ether (oxygen from 4-hydroxyphenyl and carbon 7 from benzo[b]thiopen-6-ol) linked homodimer and asymmetrical ether (oxygen and carbon 7 from benzo[b]thiopen-6-ol) linked homodimer, respectively. The structures of the homodimers RD1, 3 and 4 provided evidence for free radical metabolism of raloxifene by predominantly CYP3A4 in human liver microsomes to oxygen-centered phenoxy radicals from 4-hydroxyphenyl and benzo[b]thiopen-6-ol moieties. Further delocalization to ortho carbon-centered radical was only observed for benzo[b]thiopen-6-ol derived phenoxy radical.

Download full-text PDF

Source
http://dx.doi.org/10.3109/00498254.2012.662306DOI Listing

Publication Analysis

Top Keywords

human liver
16
liver microsomes
16
carbon benzo[b]thiopen-6-ol
12
benzo[b]thiopen-6-ol linked
12
linked homodimer
12
free radical
8
radical metabolism
8
metabolism raloxifene
8
cyp3a4 human
8
major homodimer
8

Similar Publications

Targeting p38γ synergistically enhances sorafenib-induced cytotoxicity in hepatocellular carcinoma.

Cell Biol Toxicol

January 2025

Division of Abdominal Tumor Multimodality Treatment, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, 610041, Chengdu, Sichuan Province, China.

Sorafenib (Sora) is a first-line treatment for patients with advanced hepatocellular carcinoma (HCC). It can significantly improve the survival rate of patients with advanced HCC, but it is prone to drug resistance during treatment, so the therapeutic effect is extremely limited. Here, we demonstrate that an elevated expression of protein kinase p38γ in hepatocellular carcinoma cells diminishes the tumor cells' sensitivity to Sora.

View Article and Find Full Text PDF

Background: Marathon training and running have many beneficial effects on human health and physical fitness; however, they also pose risks. To date, no comprehensive review regarding both the benefits and risks of marathon running on different organ systems has been published.

Main Body: The aim of this review was to provide a comprehensive review of the benefits and risks of marathon training and racing on different organ systems.

View Article and Find Full Text PDF

Exploring the efficacy of fluorouracil and platinum based chemotherapy in advanced hepatocellular carcinoma to bridge the treatment gap in resource limited settings.

Sci Rep

January 2025

Division of Medical Oncology, Department of Internal Medicine, College of Medicine, St. Vincent's Hospital, The Catholic University of Korea, 93 Jungbu-daero, Paldal-gu, Suwon, 16247, Korea.

Advanced hepatocellular carcinoma (HCC) poses treatment challenges, especially where access to multi-kinase inhibitors and ICIs is limited by high costs and lack of insurance. This study evaluates the effectiveness of 5-fluorouracil (5-FU) plus platinum-based chemotherapy as an alternative systemic treatment for advanced HCC. A retrospective analysis of advanced HCC patients treated with 5-FU plus platinum-based chemotherapy was conducted.

View Article and Find Full Text PDF

Stromal architecture and fibroblast subpopulations with opposing effects on outcomes in hepatocellular carcinoma.

Cell Discov

January 2025

Department of Liver Surgery and Transplantation, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China.

Dissecting the spatial heterogeneity of cancer-associated fibroblasts (CAFs) is vital for understanding tumor biology and therapeutic design. By combining pathological image analysis with spatial proteomics, we revealed two stromal archetypes in hepatocellular carcinoma (HCC) with different biological functions and extracellular matrix compositions. Using paired single-cell RNA and epigenomic sequencing with Stereo-seq, we revealed two fibroblast subsets CAF-FAP and CAF-C7, whose spatial enrichment strongly correlated with the two stromal archetypes and opposing patient prognosis.

View Article and Find Full Text PDF

Biochemical, structural, and cellular characterization of S-but-3-yn-2-ylglycine as a mechanism-based covalent inactivator of the flavoenzyme proline dehydrogenase.

Arch Biochem Biophys

January 2025

Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States; Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States. Electronic address:

The mitochondrial flavoenzymes proline dehydrogenase (PRODH) and hydroxyproline dehydrogenase (PRODH2) catalyze the first steps of proline and hydroxyproline catabolism, respectively. The enzymes are targets for chemical probe development because of their roles in cancer cell metabolism (PRODH) and primary hyperoxaluria (PRODH2). Mechanism-based inactivators of PRODH target the FAD by covalently modifying the N5 atom, with N-propargylglycine (NPPG) being the current best-in-class of this type of probe.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!