Naphthofluorescein (Naphthafluorescein) is a Mint3 inhibitor with potential antitumor and anti-inflammatory activities, inhibits the interaction between HIF-1 and Mint3, inhibits Mint3-dependent HIF-1 activity, and inhibits glycolytic activity in cancer cells and macrophages without showing significant in vitro cytotoxicity or in vivo side effects. Naphthofluorescein is also a fluorescent pH-sensitive probe for functional Cherenkov imaging.

Naphthofluorescein (compound 19) (0-10 μM; 24 h; HT1080 cells) significantly suppresses HIF-1 reporter activity in a concentration-dependent manner.[1]

Naphthofluorescein (compound 19) (100 mg/kg; i.p.; once daily; 5 days followed by 2 days off for 2 weeks; Male C57BL/6J mice) significantly suppresses tumour growth in subcutaneous E0771 cells and attenuates tumour growth in MDA-MB-231 and AsPC-1 cells in immunodeficient mice. It inhibits tumour growth in human cancer cells in an FIH-1-dependent manner and does not affect FIH-1-depleted MDA-MB-231 cells. No weight loss, histological abnormalities in the lung, liver, and kidney, or severe adverse effects were observed in the mice for at least 2 weeks.[1]

Naphthofluorescein as a pH-sensitive fluorescent probe
Procedure
1. 1 mL of HeLa cell suspension (5 × 104 cells) was seeded in a 35 mm glass-bottom microwell dish (MatTek) and cultured overnight;
2. The cells were gently washed twice with DPBS and treated with Naphthofluorescein-labeled phenol red-free peptide (5 pm) in HEPES-supplemented DMEM containing 1% FBS at 37°C in the presence of 5% CO2 for 2 h;
3. After removing the culture medium, the cells were gently rinsed twice with DPBS and imaged on a live cell imaging confocal microscope equipped with a 60x oil objective.

The above information is based on published literature. Experimental procedures should be appropriately modified to meet specific research demands.

Ethanol: 2 mg/mL (4.63 mM), Sonication is recommended.

DMSO: 100 mg/mL (231.26 mM), Sonication is recommended.

DMF: 10 mg/mL (23.13 mM), Sonication is recommended.

DMF:PBS (pH 7) (1:10): 0.09 mg/mL (0.21 mM), Sonication is recommended.