Uptake of the Carborane Derivative of Cholesteryl Ester by Glioma Cancer Cells Is Mediated Through LDL Receptors

Synthesis of a carborane-containing cholesterol derivative and evaluation as a potential dual agent for MRI/BNCT applications

In this study the synthesis and characterization of a new dual, imaging and therapeutic, agent is proposed with the aim of improving the efficacy of Boron Neutron Capture Therapy (BNCT) in cancer treatment. The agent (Gd-B-AC01) consists of a carborane unit (ten boron atoms) bearing a cholesterol unit on one side (to pursue the incorporation into the liposome bi-layer) and a Gd(iii)/1,4,7,10-tetraazacyclododecane monoamide complex on the other side (as a MRI reporter to attain the quantification of the B/Gd concentration). In order to endow the BNCT agent with specific delivery properties, the liposome embedded with the MRI/BNCT dual probes has been functionalized with a pegylated phospholipid containing a folic acid residue at the end of the PEG chain. The vector allows the binding of the liposome to folate receptors that are overexpressed in many tumor types, and in particular, in human ovarian cancer cells (IGROV-1). An in vitro test on IGROV-1 cells demonstrated that Gd-B-AC01 loaded liposomes are efficient carriers for the delivery of the MRI/BNCT probes to the tumor cells. Finally, the BNCT treatment of IGROV-1 cells showed that the number of surviving cells was markedly smaller when the cells were irradiated after internalization of the folate-targeted GdB10-AC01/liposomes.

Antitumor Activity of Liposomal Naphthoquinone Esters Isolated from Thai Medicinal Plant: Rhinacanthus nasutus KURZ

We previously observed that rhinacanthins-C, -N and -Q, three main naphthoquinone esters isolated from the roots of Thai medicinal plant; Rhinacanthus nasutus KURZ. (Acanthaceae) induced apoptosis of human cervical carcinoma HeLaS3 cells. Since these rhinacanthins showed limited solubility in aqueous medium, we attempted to entrap them into liposomal membrane: Liposomalization enabled injection of the drugs and the drugs were expected to transfer to lipoproteins in the bloodstream. Liposomal formulations of rhinacanthins-C, -N and -Q showed strong antiproliferative activity against HeLaS3 cells with the IC50 values of 32, 17, 70 microM; 19, 17, 52 microM and 2.7, 2.0 and 5.0 microM for the exposure time of 24, 48, and 72 h, respectively. These liposomes suppressed the tumor growth in Meth-A sarcoma-bearing BALB/c mice at the dose of 5.0 mg/kg/d for 10 d. Among rhinacanthins, liposomal rhinacanthin-N significantly suppressed solid tumor growth. Based on these results, our findings demonstrated that rhinacanthin-N suppressed tumor growth in vivo, and suggested that liposomes are useful for preparing injectable formulation of hydrophobic drugs.