NR4A1 and cancer: As shown in Supplemental Figure S3, TTD (5–20 μM), except for the mild toxicity to HaCaT cells at 20 μM, did not significantly affect the viability of normal cells with very low NR4A1 expression, indicating that NR4A1-dependent survival mechanisms may not be important for these normal cells, and TTD has specific cytotoxicity to cancer cells overexpressing NR4A1.