Vismodegib-loaded nanoformulation for topical skin cancer therapy: reducing drug amounts while reaching supra-therapeutic concentrations

CALIENNI, M. N.; LLOVERA, R.; PAOLINO, DONATELLA; FRESTA, MASSIMO; ALONSO, S. DEL V.; MONTANARI, JORGE

Congreso; Nanoinnovation 2020; 2020

Basal cell carcinoma (BCC) is the most common type of skin cancer, representing 80% of all cases. Genetic alterationsleading to aberrant constitutive activation of the Hedgehog (Hh) signaling pathway are associated with the developmentof most BCC. Vismodegib (Erivedge®, Genentech) is a first-in-class selective inhibitor of the Hh signaling pathwayapproved by the US Food and Drug Administration in 2012 for the treatment of locally advanced and metastatic BCC.Currently, the treatment with Vismodegib consists of the daily oral administration of Erivedge® capsules. However, thereare several side effects associated with the systemic administration of this active principle that frequently causes patientsto discontinue treatment. On the other hand, topical drug-delivery shows potential over systemic delivery in thetreatment of dermatological diseases due to the possible reduction of side effects and the increment of the local drugconcentrations. However, the stratum corneum (SC) of the human skin forms an effective barrier. Particularly,nanomedicine provides tools to overcome the SC barrier which allow the targeted transport of actives through nanodrug delivery systems. One of the lipid-based nanosystems that has successfully achieved the transport of actives throughthe SC to deeper layers of the skin are the ultradeformable liposomes (UDL). UDL are highly elastic liposomes, which canpenetrate across the SC at the body temperature, impelled by the transdermal hydration gradient and dehydrationpressure. Therefore, this work aimed to obtain and characterize Vismodegib-loaded UDL (UDL-Vis) as a potential topicaltherapy against BCC.UDL-Vis were prepared with soy phosphatidylcholine and sodium cholate, and the obtained formulation wascharacterized by several techniques, both experimental and in silico. We have determined the mean size, ζ potential,stability over time, liposomal deformability after incorporation of the drug, and we have characterized the interactionbetween Vismodegib and the liposomal membrane. Moreover, in vitro penetration of UDL-Vis in human skin was assessedwith the Saarbrücken Penetration Model. UDL-Vis cytotoxicity, cellular uptake, and the induction of apoptosis weretested in two human cell lines (HaCaT and SK-Mel-28), which present the Hh pathway activated. Finally, the toxicity ofUDL-Vis was tested in vivo in zebrafish (Danio rerio) larvae. We have chosen zebrafish as an intermediate model betweenin vitro determinations and in vivo studies with mammals because it is a growing model in the field of nanotoxicology.We have obtained a nanoformulation with high encapsulation efficiency, achieving a concentration in the viableepidermis of human skin almost thrice higher than the required dose for BCC treatment, employing around 2500 lessdrug than an oral dose. Remarkably, the incorporation of Vismodegib to UDL increased its cytotoxic effects, induced ahigher rate of apoptosis, and caused effects at lower concentrations than the free drug in vitro. Besides, this work bringsnew information about the toxicological effects of Vismodegib and this nanoformulation in zebrafish, data which areimportant for further studies in a murine model of BCC. In sum, UDL-Vis could not only allow the topical delivery of thedrug non-invasively but also enhance the performance of the drug due to a possible synergy between the liposomalmatrix and Vismodegib.