PMID: 8431976Jan 1, 1993Paper

Targeting chemosensitizing doses of toremifene based on protein binding

Cancer Chemotherapy and Pharmacology
G WurzV Wiebe


Toremifene is currently being evaluated as a chemosensitizing agent in doxorubicin-resistant patients. Although concentrations of > 2 microM reverse resistance in vitro, target concentrations required to reverse multidrug resistance (MDR) in vivo may be highly influenced by variables such as protein binding in serum. We examined the effects of high serum concentrations on the cellular accumulation of toremifene in an MDR MDA-MB-A-1 human breast-cancer cell line. We then examined the cellular accumulation of doxorubicin at various toremifene concentrations in 5% - 100% serum. We also measured the concentrations of toremifene and its major metabolites in plasma specimens obtained from two patients receiving 360 mg/day for 5 days in a phase I study. Our results show that (1) high serum concentrations decrease toremifene accumulation, (2) toremifene concentrations of < or = 2.5 microM enhance doxorubicin accumulation, and (3) patients achieve plasma toremifene concentrations of 10-15 microM following doses of 360 mg/day x 5 days. Our findings suggest that in vivo toremifene concentrations well above those used to reverse resistance in vitro are required to overcome the effect of high serum-protein binding.


Jan 1, 1990·Cancer Chemotherapy and Pharmacology·V J WiebeM DeGregorio
Sep 1, 1989·Journal of Clinical Oncology : Official Journal of the American Society of Clinical Oncology·M DeGregorioV Wiebe
Apr 1, 1989·Journal of Clinical Oncology : Official Journal of the American Society of Clinical Oncology·M M Gottesman, I Pastan
Jun 21, 1989·Journal of the National Cancer Institute·B A Chabner, A T Fojo
Jul 1, 1988·Pharmacology & Toxicology·H SipiläT Halme
Jan 13, 1984·Biochemical and Biophysical Research Communications·H Y Lam
Dec 1, 1982·Cancer Chemotherapy and Pharmacology·M DeGregorioJ R Wilbur


Jul 26, 2008·Breast Cancer : the Journal of the Japanese Breast Cancer Society·Shigehira Saji, Katsumasa Kuroi
Dec 1, 1996·Lung Cancer : Journal of the International Association for the Study of Lung Cancer·E R SalomaaJ Komi
Dec 7, 2000·Clinical Pharmacokinetics·T L TarasM DeGregorio
Oct 17, 1998·Cancer Investigation·D L Fairclough

Related Concepts

Trending Feeds


Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Hereditary Sensory Autonomic Neuropathy

Hereditary Sensory Autonomic Neuropathies are a group of inherited neurodegenerative disorders characterized clinically by loss of sensation and autonomic dysfunction. Here is the latest research on these neuropathies.

Glut1 Deficiency

Glut1 deficiency, an autosomal dominant, genetic metabolic disorder associated with a deficiency of GLUT1, the protein that transports glucose across the blood brain barrier, is characterized by mental and motor developmental delays and infantile seizures. Follow the latest research on Glut1 deficiency with this feed.

Regulation of Vocal-Motor Plasticity

Dopaminergic projections to the basal ganglia and nucleus accumbens shape the learning and plasticity of motivated behaviors across species including the regulation of vocal-motor plasticity and performance in songbirds. Discover the latest research on the regulation of vocal-motor plasticity here.

Neural Activity: Imaging

Imaging of neural activity in vivo has developed rapidly recently with the advancement of fluorescence microscopy, including new applications using miniaturized microscopes (miniscopes). This feed follows the progress in this growing field.

Nodding Syndrome

Nodding Syndrome is a neurological and epileptiform disorder characterized by psychomotor, mental, and growth retardation. Discover the latest research on Nodding Syndrome here.

LRRK2 & Microtubules

Mutations in the LRRK2 gene are risk-factors for developing Parkinson’s disease (PD). LRRK2 mutations in PD have been shown to enhance its association with microtubules. Here is the latest research.