Curcumin is a biologically active copper chelator with antitumor activity

Area of Science:

• Natural product chemistry
• Cancer biology
• Metal ion chelation

Background:

• Curcumin exhibits antitumor properties by targeting multiple cell signaling pathways.
• Its keto-enol tautomerism allows high-affinity chelation of transition metal ions.

Purpose of the Study:

• To investigate if curcumin's antitumor activity is mediated by copper chelation.
• To explore the role of copper in tumor growth and angiogenesis.

Main Methods:

• Validated curcumin's copper chelation using US/VIS spectroscopy.
• Assessed antitumor effects and in vivo copper removal in a murine xenograft model.
• Determined curcumin's impact on copper-induced MAPK activation and cell proliferation in vitro.

Main Results:

• Curcumin suppressed A549 xenograft growth, similar to the metal chelator ammonium tetrathiomolybdate (TM).
• Tumor growth inhibition correlated with reduced serum copper levels.
• Copper promoted cell proliferation via Erk/MAPK activation; curcumin, U0126, or CTR1 knockdown blocked this effect.

Conclusions:

• Curcumin's antitumor effect is attributed to its copper chelation capability.
• Copper chelation may be a common mechanism for biologically active polyphenols, including flavonoids.