Synthesis of nitrogen mustard-based fluorophores for cell imaging and cytotoxicity studies

Nitrogen mustards are important alkylating anticancer drugs used for neoplasms treatment. However, little research about the integration of luminophore into nitrogen mustard-based compounds for both imaging and therapeutic application was reported. In this study, we report a series of novel nitrogen mustard-containing 1-furyl-2-en-1-one and 1-thienyl-2-en-1-one derivatives as intramolecular charge transfer-based luminophore for research in both imaging subcellular localization and antiproliferation toward lung cancer cells. The target products were prepared by Knoevenagel condensation and characterized by nuclear magnetic resonance and high-resolution mass spectrometer. The absorption and fluorescence studies were carried out by ultraviolet-visible and fluorescence spectrophotometers, respectively. Cell morphology was observed under an inverted microscope. Cytotoxicity test was detected by MTT assay. Cellular localization was observed by a confocal laser scanning microscope. Colony formation ability was carried out by colony formation assay. Cell migration ability was detected by transwell migration assay. Differences between the two groups were analyzed by two-tailed Student's t-test. The difference with P < 0.05 (*) was considered statistically significant. The compounds were synthesized in high yield. The λ_max and Stokes shift of these compounds reach up to 567 and 150 nm, respectively. These compounds exhibited good antiproliferative activity against lung cancer cells, with compound 3h exhibiting the best IC₅₀ of 13.1 ± 2.7 μM. Furthermore, the selected compound 3h is located preferentially in lysosomes and a small amount in nuclei, effectively inhibiting cell colony formation and migration abilities toward A549 cells. These findings suggested that nitrogen mustard-based fluorophores might be a potential effective chemotherapeutic agent in lung cancer therapy.