Molecular Aspects of the Interaction of Hoechst-33258 with GC-Rich Promoter Region of c-met

Abstract

The c-Met signaling pathway is one of the main regulators of cell proliferation, differentiation, apoptosis, and other cellular processes. As aberrant expression of c-Met has been implicated in tumor growth, invasion, and metastasis, c-Met is recognized as a promising target for cancer therapeutics. In continuation of our search for small molecules with anticancer properties, we investigated the binding of bis-benzimidazole derivative Hoechst-33258 to the promoter region 24RY, -142 to -119 (5'-GGGGCAGAGGCGGGAGGAAACGCG-3', 24R and its complement 5'-CGCGTTTCCTCCCGCCTCTGCCCC-3', 24Y), upstream to the transcriptional start site of the c-met gene. Strong complexation of duplex 24RY-Hoechst is revealed by a high binding constant K, 3.25 x 10(5) M(-1), with significant changes of Delta DeltaG (-10 kcal/mol), Delta DeltaH (-83 kcal/mol), Delta DeltaS (-241 cal/[mol K]), and melting temperature (DeltaT(m) = +8 degrees C). This is accompanied by bathochromic shift of 10 nm, 50% hypochromism at 340 nm, isobestic points at 302 and 369 nm in absorption spectra, and induced emission band at 465 nm in the fluorescence spectra of Hoechst. Molecular modeling data demonstrated that Hoechst binds to consecutive GGs in the minor groove of 24RY containing residues 12-17. Therefore, Hoechst-33258 can be a potential anticancer agent against malignancies associated with c-Met upregulation.

Optical Polymorphism of Liquid–Crystalline Dispersions of DNA at High Concentrations of Crowding Polymer

“…Commercial DNA-specific dyes SYBR Green I (SG; Lumiprobe, Cockeysville, MD, USA) and Hoechst 33258 (Ht58; Paneko, Moscow, Russia) were used to study an induced circular dichroism (ICD). Concentration of the dyes as well as DNA concentration was determined spectrophotometrically on a Shimadzu UV-3101 PC spectrophotometer (Kyoto, Japan) using the molar absorption coefficients: ε 260 ≈ 6600 M −1 cm −1 (DNA) [62], ε 498 ≈ 73,000 M −1 cm −1 (SG) [63], ε 340 ≈ 42,000 M −1 cm −1 (Ht58) [64]. SG was also used as a fluorescent probe.…”

Interaction of doxorubicin with a regulatory element of hmga1 and its in vitro anti-cancer activity associated with decreased HMGA1 expression

“…We have been working on the interaction of various anti-cancer drugs/small peptides with various proto-oncogenes in order to get insights into the transcriptional regulation of genes [29][30][31][32][33]. Doxorubicin (DOX) is a member of glycosidic anthracycline antibiotic which is persuasively used in a wide range of human malignancies [34].…”

Interaction of adriamycin with a promoter region of hmga1 and its inhibitory effect on HMGA1 expression in A431 human squamous carcinoma cell line

“…19 However, our present approach is to alter the hmga1 expression by targeting and blocking the promoter region by adriamycin (ADM). We have been working on interaction of various anti-cancer drugs/small peptides with various protooncogenes in order to understand the transcriptional regulation of genes like c-met [20][21][22] and c-myc. 23,24 ADM, the most potent member of glycosidic anthracycline antibiotics is widely used in chemotherapy because of its activity against a broad range of human malignancies.…”