Figure 4.

Curcumin leads to specific downregulation of the MYC protein thereby inducing a cross-link with TRRAP. (A–D) HEK293T cells were incubated with increasing concentrations (5–40 µM) of curcumin. Protein extracts were prepared after 24 h and analyzed by immunoblotting using (A) MYC-, (B) TRRAP‑, (C) TP53, or (D) α-tubulin specific antibodies. The arrow in (C) depicts the position of a potential cross-linked TP53 dimer. (E) HEK293T cells were incubated with increasing concentrations (5–40 µM) of half-curcumin and tested for MYC expression as under (A). (F) Expression analysis of the BRAF oncoprotein in the presence or absence of curcumin, or half-curcumin as described under (A, E). (G) Structural formulas of curcumin (CRM) and of a non-functional curcumin-derivative termed half-curcumin. A representative experiment (n = 2) is shown (A–F).