Magnetoliposomes as carriers for promising antitumor thieno[3,2-b]pyridin-7-arylamines: photophysical and biological studies

Magnetoliposomes containing superparamagnetic manganese ferrite nanoparticles were tested as nanocarriers for two new promising antitumor drugs, a N-(3-methoxyphenyl)thieno[3,2-b]pyridin-7-amine (1) and a N-(2-methoxy-phenyl)thieno[3,2-b]pyridin-7-amine (2). The fluorescence emission of both compounds was studied in different polar and non-polar media, evidencing a strong intramolecular charge transfer character of the excited state of both compounds. These in vitro potent antitumor thienopyridine derivatives were successfully incorporated in both aqueous and solid magnetoliposomes, with encapsulation efficiencies higher than 75%. The magnetic properties of magnetoliposomes containing manganese ferrite nanoparticles were measured for the first time, proving a superparamagnetic behaviour. Growth inhibition assays on several human tumor cell lines showed very low GI50 values for drug-loaded aqueous magnetoliposomes, comparing in most cell lines with the ones previously obtained using the neat compounds. These results are important for future drug delivery applications using magnetoliposomes in oncology, through a dual therapeutic approach (simultaneous chemotherapy and magnetic hyperthermia).This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2013), CQUM (UID/QUI/00686/2013 and 2016) and CIMO (UID/AGR/00690/2013), the latter also supported by FEDER -Program PT2020. FCT, POPH-QREN and FSE are acknowledged for the PhD grant of A. R. O. Rodrigues (SFRH/BD/90949/2012), the postdoc grant of R. C. Calhelha (SFRH/BPD/68344/2010) and for financial support to MAP-Fis PhD Programme.