Optimizing the Pharmacological Properties of Discoidal Polymeric Nanoconstructs Against Triple-Negative Breast Cancer Cells

Abstract

Fine-tuning loading and release of therapeutic and imaging agents associated with polymeric matrices is a fundamental step in the preclinical development of novel nanomedicines. Here, 1,000 × 400 nm Discoidal Polymeric Nanoconstructs (DPNs) were realized via a top-down, template-based fabrication approach, mixing together poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol)-diacrylate (PEG-DA) chains in a single polymer paste. Two different loading strategies were tested, namely the "direct loading" and the "absorption loading." In the first case, the agent was directly mixed with the polymeric paste to realize DPNs whereas, in the second case, DPNs were first lyophilized and then rehydrated upon exposure to a concentrated aqueous solution of the agent. Under these two loading conditions, the encapsulation efficiencies and release profiles of different agents were systematically assessed. Specifically, six agents were realized by conjugating lipid chains (DSPE) or polymeric chains (PEG) to the near-infrared imaging molecule Cy5 (DSPE-Cy5 A and DSPE-Cy5 B); the chemotherapeutic molecules methotrexate (DSPE-MTX and PEG-MTX) and doxorubicin (LA-DOX and DSPE-DOX). Moderately hydrophobic compounds with low molecular weights (MW) returned encapsulation efficiencies as high as 80% for the absorption loading. In general, direct loading was associated with encapsulation efficiencies lower than 1%. The agent hydrophobicity and MW were shown to be critical also in tailoring the release profiles from DPNs. On triple-negative breast cancer cells (MDA-MB-231), absorption loaded DOX-DPNs showed cytotoxic activities comparable to free DOX but slightly delayed in time. Preliminary in vivo studies demonstrated the high stability of Cy5-DPNs. Collectively, these results demonstrate that the pharmacological properties of DPNs can be finely optimized by changing the loading strategies (direct vs. absorption) and compound attributes (hydrophobicity and molecular weight).

Synthesis of Two Methotrexate Prodrugs for Optimizing Drug Loading into Liposomes

“…The coadministration of the two prodrugs and the administration of combo liposomes showed an IC 50 very similar to DSPE-MTX: IC 50 values for the combo were found to be equal to 0.6 ± 0.1 µM and 0.9 ± 0.1 µM (free prodrugs and combo-LIP, respectively). These results were in agreement with results obtained in other works produced by our group and others [ 31 , 45 , 49 ]. In summary, a slight difference in IC 50 among MTX, DSPE-MTX, PEG-MTX and the liposomal formulation derived was found.…”

“…DSPE-MTX was synthesized as reported by Ferreira and coworkers with some modifications [ 49 ]. Briefly, 30 mg of MTX was incubated with 1 eq.…”

“…A catalytic amount of triethylamine (TEA) was added to the reaction and was left to stir for 16 h. The intended product was precipitated with cold diethyl ether, and then washed 3 times with cold diethyl ether to obtain the final product with a yield of 90%. More details of this procedure can be found in the previous literature [ 49 ].…”

“…DSPE-Cy5 was synthetized as reported elsewhere [ 49 ]. Briefly, DSPE-NH2 (15 mg) was dissolved in dichloromethane (DCM)/cethanol (MeOH), 2:1 v / v .…”

Modulating Lipoprotein Transcellular Transport and Atherosclerotic Plaque Formation in ApoE–/– Mice via Nanoformulated Lipid–Methotrexate Conjugates

“…DSPE-MTX was synthesized as reported by Ferreira and co-workers with some modifications. 49 Briefly, MTX was incubated with 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC)/ N -hydroxysuccinimide (NHS) in dimethyl sulfoxide (DMSO) for 30 min, at room temperature. A solution of DSPE in DMSO was added to the previous solution.…”