Modulation of Hsp70 Expression and Function

For induction and inhibition of Hsp70 expression or function, certain chemicals were utilized, including the HSF1 inducer U-133, which was previously selected from the library of small molecules of the Pacific Institute of Bioorganic Chemistry, Russian Academy of Sciences (Vladivostok, Russia). U-133 is an acetylated tris-O-glucoside echinochrome and it was obtained by the chemical modification of the sea urchins pigment echinochrome [31 ]. U-133 was found to induce synthesis in human U-937 promonocytes [24 (link)] and in the substantia nigra of rats [25 (link)]. The HSF1 inhibitor CL-43 was previously shown to inhibit Hsp70 synthesis in various cancer cells [26 (link)]. Moreover, 2-phenylethynesulfonamide (PES) or pifithrin-μ, an inhibitor of the chaperonic function of Hsp70 [32 (link)], was purchased at Sigma-Aldrich (St. Louis, MO, USA).