The association of statins plus LDL receptor‐targeted liposome‐encapsulated doxorubicin increases in vitro drug delivery across blood–brain barrier cells

Abstract

BACKGROUND AND PURPOSEThe passage of drugs across the blood-brain barrier (BBB) limits the efficacy of chemotherapy in brain tumours. For instance, the anticancer drug doxorubicin, which is effective against glioblastoma in vitro, has poor efficacy in vivo, because it is extruded by P-glycoprotein (Pgp/ABCB1), multidrug resistance-related proteins and breast cancer resistance protein (BCRP/ABCG2) in BBB cells. The aim of this study was to convert poorly permeant drugs like doxorubicin into drugs able to cross the BBB. EXPERIMENTAL APPROACHExperiments were performed on primary human cerebral microvascular endothelial hCMEC/D3 cells, alone and co-cultured with human brain and epithelial tumour cells. KEY RESULTSStatins reduced the efflux activity of Pgp/ABCB1 and BCRP/ABCG2 in hCMEC/D3 cells by increasing the synthesis of NO, which elicits the nitration of critical tyrosine residues on these transporters. Statins also increased the number of low-density lipoprotein (LDL) receptors exposed on the surface of BBB cells, as well as on tumour cells like human glioblastoma. We showed that the association of statins plus drug-loaded nanoparticles engineered as LDLs was effective as a vehicle for non-permeant drugs like doxorubicin to cross the BBB, allowing its delivery into primary and metastatic brain tumour cells and to achieve significant anti-tumour cytotoxicity. CONCLUSIONS AND IMPLICATIONSWe suggest that our 'Trojan horse' approach, based on the administration of statins plus a LDL receptor-targeted liposomal drug, might have potential applications in the pharmacological therapy of different brain diseases for which the BBB represents an obstacle.

The Cross-Talk between Canonical and Non-Canonical Wnt-Dependent Pathways Regulates P-Glycoprotein Expression in Human Blood–Brain Barrier Cells

“…2,3,6 The activation of RhoA and RhoAK is known to enhance the Pgp activity in BBB cells. 11 It is not known: (1) whether the Wnt/RhoA/ RhoAK axis controls also the Pgp expression; (2) whether the canonical and non-canonical Wnt pathways cooperate in regulating the Pgp levels in BBB cells.…”

“…The permeability to dextran-fluorescein isothiocyanate (molecular weight 70 kDa), [ 14 C]-inulin (molecular weight range: 5.0 to 5.5 kDa; 10 mCi/mmol; PerkinElmer), sodium fluorescein (molecular weight: 376.27 Da) was taken as a parameter of tight junction integrity 11,15 and measured as previously reported. 6,16 To measure the permeability coefficient of doxorubicin across the BBB monolayer, wild-type or RhoA-silenced hCMEC/D3 cells were grown for 7 days up to confluence in 6-multiwell Transwell devices, and treated as reported under the Results section.…”

“…To evaluate the RhoA activity, the RhoA-GTP-bound fraction, taken as an index of monomeric G-proteins activation, 11 was measured using the G-LISA RhoA Activation Assay Biochem Kit (Cytoskeleton), according to the manufacturer's instructions. The absorbance was read at 450 nm, using a Packard EL340 microplate reader (Bio-Tek Instruments, Winooski, VT, USA).…”

“…8,9 The Wnt non-canonical transducers RhoA and RhoAK regulate the integrity of tight junctions and the paracellular transport of substrates across BBB, 10 as well as the activity of Pgp. 11 It is not known whether Wnt/RhoA/RhoAK pathway controls also the expression of Pgp.…”

ABCG2 gene amplification and expression in esophageal cancer cells with acquired adriamycin resistance

“…The multidrug transporters (ABC transporters) are present in a number of normal tissues with barrier functions (18)(19)(20)(21)(22)(23), and may modulate the absorption of orally administered cytotoxic compounds. For example, ABCG2 is expressed mainly in the placenta, and it is indicated that ABCG2 may control the penetration of drugs from the maternal plasma into the fetus, thus protecting the fetus against the potential toxicity of the drugs (24).…”