Large Amino Acid Transporter 1 Selective Liposomes of l-DOPA Functionalized Amphiphile for Combating Glioblastoma

Abstract

Despite significant progress in neurosurgery and radiation therapy during the past decade, overall survivability (OS) of glioblastoma patients continues to be less than 2 years. The scope of systemic chemotherapy is greatly limited by poor drug transport across the blood brain barrier (BBB) and, thereby, suboptimal drug accumulation in glioma tissue. To this end, use of large amino acid transporter-1 (LAT1) overexpressed both on brain capillary endothelial cells (BCECs) and glioma cells has begun. Prior reports on the use of LAT1 mediated delivery of model drugs showed their brain accumulations. However, in depth in vivo glioblastoma regression studies aimed at examining the therapeutic potential of LAT1 mediated delivery of potent chemotherapeutics to brain tumor tissues have not yet been undertaken. Herein, we report on the development of a nanometric (100-135 nm) promising LAT1 selective liposomal drug carrier prepared from a novel l-3,4-dihydroxyphenylalanine (l-DOPA) functionalized amphiphile (Amphi-DOPA). In vitro studies using Rh-PE labeled liposomes of Amphi-DOPA both in untreated glioma (GL261) cells and in GL261cells preincubated with LAT1 antibody revealed LAT1 mediated cellular uptake. Intravenously administered NIR-dye labeled liposomes of Amphi-DOPA in glioblastoma-bearing mice showed preferential accumulation of the dye in brain tissue. Notably iv administration of WP1066-loaded liposomes of Amphi-DOPA enhanced the overall survivability of C57BL/6J mice bearing orthotopically established mouse glioblastoma by ∼60% compared to that for the untreated mouse group. Furthermore, we show that the OS of established glioblastoma-bearing mice can be significantly enhanced (by >300% compared to that for the untreated mouse group) when the presently described LAT1 mediated targeted chemotherapy with WP1066-loaded liposomes of Amphi-DOPA is combined with in vivo DC-targeted DNA vaccination using a survivin (a glioblastoma antigen) encoded DNA vaccine. The present findings open a new door for LAT1 mediated systemic chemotherapy of glioblastoma.

Targeted alpha therapy using astatine (211At)-labeled phenylalanine: A preclinical study in glioma bearing mice

“…All cells were maintained at 37°C in a humidified incubator containing 5% CO 2 and were washed with phosphate-buffered saline (PBS) and harvested with trypsin as necessary. LAT1 expression of these cells were confirmed in previous studies [16,23].…”

“…Moreover, we demonstrated the functional expression of LAT1 in these tumors using histology and western blot analyses [5,15]. A western blot analysis of GL261 cells also revealed strong expression of LAT1 [16]. In our current in vitro cellular uptake analysis, we demonstrated the transport of 211 At-PA via system L amino acid transporters.…”

Transporter-Targeted Nano-Sized Vehicles for Enhanced and Site-Specific Drug Delivery

“…In vivo studies showed that glutamate-conjugated liposomes could effectively cross the BBB and selectively distribute into the brain. Similar results were obtained with L-DOPA-conjugated liposomes, again targeting LAT1 in BBB and glioma [ 85 ].…”

L-Type amino acid transporter 1 as a target for drug delivery

“…In the biodistribution study, the NIR-dye labelled liposomes of Amphi-Dopa were detected in the brain, liver and spleen at 4 h after i.v. administration but predominantly in the brain at 24 h in glioblastoma-bearing mice (94). The i.v.…”

“…injection of fluorescent-labelled nanoparticles in glioma model nude mice without any signs of systemic toxicity (93). In another study, Bhunia et al (2017) developed LAT1 a selective liposomal drug carrier prepared from a novel L-Dopa functionalized amphiphile (Amphi-Dopa) (94). In the biodistribution study, the NIR-dye labelled liposomes of Amphi-Dopa were detected in the brain, liver and spleen at 4 h after i.v.…”