Formulation, Characterization, and Antitumor Properties of Trans- and Cis-Citral in the 4T1 Breast Cancer Xenograft Mouse Model

• Published in: Pharmaceutical research Vol. 32; no. 8; pp. 2548 - 2558
• Main Authors: Zeng, San, Kapur, Arvinder, Patankar, Manish S., Xiong, May P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2015; Springer Nature B.V
• Subjects: Animals; Antineoplastic Agents - administration & dosage; Antineoplastic Agents - chemistry; Antineoplastic Agents - therapeutic use; Biochemistry; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Breast cancer; Breast Neoplasms - drug therapy; Cell Survival; Chemistry, Pharmaceutical; Enzyme Inhibitors - administration & dosage; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - therapeutic use; Female; Humans; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Medical Law; Mice; Mice, Inbred BALB C; Micelles; Monoterpenes - administration & dosage; Monoterpenes - chemistry; Monoterpenes - therapeutic use; Pharmacology/Toxicology; Pharmacy; Research Paper; Stereoisomerism; Studies; Tissues; Tumors; Xenograft Model Antitumor Assays; micelle; breast cancer; citral; geranial; neral
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-015-1643-0

Purpose Citral is composed of a random mixture of two geometric stereoisomers geranial ( trans -citral) and neral ( cis -citral) yet few studies have directly compared their in vivo antitumor properties. A micelle formulation was therefore developed. Methods Geranial and neral were synthesized. Commercially-purchased citral, geranial, and neral were formulated in PEG-b-PCL (block sizes of 5000:10,000, Mw/Mn 1.26) micelles. In vitro degradation, drug release, cytotoxicity, flow cytometry, and western blot studies were conducted. The antitumor properties of drug formulations (40 and 80 mg/kg based on MTD studies) were evaluated on the 4T1 xenograft mouse model and tumor tissues were analyzed by western blot. Results Micelles encapsulated drugs with >50% LE at 5–40% drug to polymer ( w/w ), displayed sustained release (t 1/2 of 8–9 h), and improved drug stability at pH 5.0. The IC 50 of drug formulations against 4T1 cells ranged from 1.4 to 9.9 μM. Western blot revealed that autophagy was the main cause of cytotoxicity. Geranial at 80 mg/kg was most effective at inhibiting tumor growth. Conclusions Geranial is significantly more potent than neral and citral at 80 mg/kg ( p  < 0.001) and western blot of tumor tissues confirms that autophagy and not apoptosis is the major mechanism of tumor growth inhibition in p53-null 4T1 cells.