C0818, a novel curcumin derivative, induces ROS-dependent cytotoxicity in human hepatocellular carcinoma cells in vitro via disruption of Hsp90 function.

Heat shock protein 90 (Hsp90) is the most common molecular chaperone that controls the maturation of many oncoproteins critical in tumor development. Hsp90 has been considered as a promising target for cancer treatment, but the clinical significance of Hsp90 and the mechanisms of Hsp90 regulating the tumor-promoting effects in hepatocellular carcinoma (HCC) remain obscure. Previous studies have shown that curcumin, a polyphenol derived from the plant turmeric (Curcuma longa), inhibits tumor growth, which may provide an effective alternative therapy for HCC.

C1206, a novel curcumin derivative, potently inhibits Hsp90 and human chronic myeloid leukemia cells in vitro.

4-(4-Pyridinyl methylene) curcumin (C1206) is a new derivative of curcumin that is more active than curcumin in inhibition of heat shock protein 90 (Hsp90) and antitumor action. In this study we investigated the relationship between C1206-induced inhibition of Hsp90 and its anti-leukemic effects. The fluorescence quenching experiments showed that C1206 seemed to bind the middle dimerization domain of Hsp90.

Studies of EPR parameters for Mn5+ -doped Li3PO4 and Li3VO4 crystals.

The EPR parameters (zero-field splitting D and g factors g parallel, g perpendicular) of Mn5+ -doped Li3PO4 and Li3VO4 crystals are calculated from the complete high-order perturbation formulas based on a molecular orbital scheme for a 3d2 ion in tetragonal MX4 clusters. These formulas include not only the contribution coming from crystal-field excitations, but also that arising from charge-transfer excitations (which is discarded in crystal field theory). The calculated results are in reasonable agreement with the observed values.

Gyromagnetic factor of Cr4+ ions in forsterite.

The average value of g factor (i.e., g ) of Cr4+ ions in forsterite (Mg2SiO4) is calculated with the cubic symmetry approximation from the complete high-order perturbation formula of g factor for 3d2 ion in cubic tetrahedral cluster.