UltraDeformable archaeosomes (UDa) as transdermal therapeutic agents against melanoma cells

LETICIA HIGA; PRISCILA SCHILRREFF; DIANA I. RONCAGLIA,; MARIA JOSE MORILLA; EDER ROMERO

Omaha

Congreso; Nano drug delivery symposium; 2010

The UltraDeformable Archaeosomes (UDa) are unilamellar liposomes composed of soybean phosphatidilcholine, sodium cholate and total polar lipids (TPL, containing polyisoprenoids glycerol ethers– (archaetidylglycerol methylphosphate, archaetidylglycerol, manosil-2-sulphate-(1-4) glycosil-archaeol, and bisphosphatidylglycerol, plus carotenoids, retinal and bacterioruberin)- from the archaea Halorubrum tebenquichense extracted from the Argentinean Patagonia, (3:3:1 w/w). Upon applied under non occlusive conditions on the skin surface, these ultradeformable liposomes spontaneously penetrate the stratum corneum up to the viable epidermis layers. We have used these liposomes loaded with Ovoalbumin (OVA-UDa) to raise adjuvancy upon topical administration on skin of BALB-c mouse. Besides, we have determined the cytotoxic effect of UDa against the cell line SK-MEL-28 (human malignant melanoma), by the MTT and LDH methods, as well as determined the level of GSH consumption. Briefly, OVA-UDa was prepared by dry thin lipid film hydration and further extrusion. OVA was suspended in 10mM Tris–HCl buffer plus 0.9% (w/v) NaCl, pH 7.4. TPL were confirmed by preparative TLC, ESI-MS and MNR. OVA-UDa resulted unilamellar vesicles, 100 nm mean diameter (Fig.1) and -50mV Z potential. The UDa exhibited the following properties: deep penetration across intact human skin, as determined by cryo sectioning and fluorescence confocal microscopy observation of UDa labelled with rhodamine-PE in lipid matrix and pyranine in the inner aqueous space, as well as tape-stripping; successful reconstitution postdehydration by speed-vac, retaining their initial ultradeformability. Four levels of OVA (0.075, 0.15, 0.3 and 0.6 mg OVA/ 0.6 mg phospholipids) were applied as OVA-UDa on neither shaved nor stripped BALB/c mice (2 cm2). We found that UDa raised systemic IgG titers significantly higher than conventional (without archaeolipids) ultradeformable liposomes (Fig.2). A strong TNFα response was also induced. Doses 1/10 of those applied on skin surface of UDa on melanoma cell line resulted cytotoxic for malignant cells, while there were no deleterious effect against a control line of fibroblast. The UDa also were capable of dealing with extreme storage conditions upon dehydration in the absence of cryoprotectants; upon rehydration UDa recovered their size distribution and ultradeformability. These results showed that OVA-UDa are capable of eliciting an antigen-dependent immune response upon transcutaneous application, an unusual penetration depth of the ultradeformable lipid matrices and a specific cytotoxicity (of UDa) against melanoma cells. Taken together, OVA-UDa could be suitable vehicles to exert a multifunctional therapeutic/prophylactic platform against malignant melanoma.