Fluorescence properties and antiproliferative effects of mono-, bis-, and tris- thiophenylnaphthalimides: Results of a comparative pilot study

A series of mono-, bis- and trisnaphthalimides with different substituents on the naphthalimide ring system was prepared. For compounds containing a thiophenyl substituent fluorescence spectroscopic measurements were performed and unexpectedly showed an increase in fluorescence emission for the bis- and trisnaphthalimide derivatives in phosphate buffered saline. Additional fluorescence microscopic experiments indicated an efficient cellular uptake of the thiophenyl substituted compound 1c into cultured tumor cells. Experiments on the inhibition of tumor cell proliferation were performed in MCF-7 breast adenocarcinoma and HT-29 colon carcinoma cells and confirmed derivatives containing a nitro substituent as the most active compounds. Compound 1c demonstrated potential as photoinducable antitumor agent.

Graphical abstractA series of mono-, bis-, and tris-naphthalimides was studied for fluorescence emission properties, biodistribution and antiproliferative effects in tumor cells.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Naphthalimides with thiophenyl substituents display environmental sensitive fluorescence emission. ► 1,8-Naphthalimides are prospective antitumor drugs. ► Antiproliferative effects can be enhanced by photoirradiation.