Synthesis, DNA-binding activity and cytotoxicity of carbamate derivatives of Hoechst 33258 in breast cancer MCF-7 cells

Alantolactone induces apoptosis and suppresses migration in MCF‑7 human breast cancer cells via the p38 MAPK, NF‑κB and Nrf2 signaling pathways

Human breast cancer is a malignant type of cancer with high prevalence. In the present study, the anticancer effects of alantolactone, a sesquiterpene lactone, on the human breast cancer cell line MCF‑7 were investigated in vitro. The MCF‑7 cell morphology changed from diamond to round subsequent to treatment with alantolactone, and the cell viability reduced significantly compared with that of the control cells. Alantolactone induced apoptosis of MCF‑7 cells by regulating the protein expression levels of B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑associated X protein, p53, caspase‑3 and caspase‑12, which are associated with the apoptotic pathway, and suppressed colony formation and migration by regulating the protein expression of matrix metalloproteinase (MMP)‑2, MMP‑7 and MMP‑9. Cell signaling pathway analysis confirmed that alantolactone increased the phosphorylation of p38, and decreased the nuclear expression levels of p65 and nuclear factor erythroid 2‑related factor 2 (Nrf2), suggesting that the apoptosis‑promoting and migration‑suppressing effect of alantolactone may partially depend on regulating the p38 MAPK, NF‑κB and Nrf2 pathways. These results also suggested that alantolactone may become a potential therapeutic strategy for treating breast cancer.

Non-covalent ligand/DNA interactions: minor groove binding agents

An understanding of the mechanism by which minor groove binding agents interact with DNA has led to the design of agents that can reversibly bind with high selectivity to extended DNA target sequences. Simple compounds, such as the polypyrroles and the bis-benzimidazoles, have been used as carriers for alkylating agents effectively directing alkylation to specific DNA sequences. The spectrum of DNA alkylation and mutation by classical alkylators, such as nitrogen mustards, has been profoundly modified by such attachment. The observed "side-by-side" binding of small polypyrrole antibiotics has led to the design of synthetic hairpin polyamides with programmable DNA sequence selectivity. These compounds are able to compete with natural substrates, such as specific transcription factors, and alter gene expression. They are being developed as artificial transcription factors, able to deliver activating peptides to specific recognition sequences, and as potential protein-DNA dimerization agents. Hairpin polyamides are also being used as carriers for the delivery of alkylators to defined DNA sites. The degree of control of gene expression thus offered by the hairpin polyamides suggests enormous promise for their clinical utility. Recent developments with other minor groove binding small molecules and technological advances are also discussed.

Synthesis, DNA Binding, Topoisomerase Inhibition and Cytotoxic Properties of 2-Chloroethylnitrosourea Derivatives of Hoechst 33258

A number of novel 2-chloroethylnitrosourea derivatives of Hoechst 33258 were synthesized and examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than Hoechst 33258. The DNA-binding ability of these compounds was evaluated by an ultrafiltration method using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2, indicated that these compounds as well as Hoechst 33258 well interact with AT base pair compared with GC pair. Binding studies indicate that these compounds bind more tightly to double-stranded DNA than the parent compound Hoechst 33258. The degree to which these compounds inhibited cell growth breast cancer cells was generally consistent with their relative DNA binding affinity. Mechanistic studies revealed that these compounds act as topoisomerase I (topo I) or topoisomerase II (topo II) inhibitors in plasmid relaxation assays.