Synthesis of Fluorinated Imidazole[4,5f][1,10]phenanthroline Derivatives as Potential Inhibitors of Liver Cancer Cell Proliferation by Inducing Apoptosis via DNA Damage.

Phenanthroline derivatives containing fluorinated imidazole ring are effective anti-neoplastic agents. Herein, a series of four fluorinated imidazole[4,5f][1,10]phenanthroline derivatives were synthesized and investigated as potential inhibitors to fight against the growth of liver cancer cells. The in vitro antitumor activity of targeted compounds have been evaluated by using MTT assay, and results showed that compound 4 (2-(2,3-difluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) exhibited excellent inhibitory effect against the growth of various tumor cells, particularly for HepG2 cells, with IC50 value of approximately 0.29 µM. This result has been further confirmed by colony formation assay, showing that compound 4 suppressed the proliferation of HepG2 cells. Moreover, cell apoptosis (AO/PI dual staining and flow cytometry) analyses as well as comet assay showed that compound 4 may induce apoptosis of HepG2 cells through triggering DNA damage. Furthermore, the in vivo anti-tumor activity were evaluated on zebrafish bearing HepG2 cells showed that compound 4 can observably block the growth of liver cancer cells. All in together, these compounds, particularly compound 4, may be developed as a potential agent to treat liver cancer in the future.

Tanshinone IIA derivatives induced S-phase arrest through stabilizing c-myc G-quadruplex DNA to regulate ROS-mediated PI3K/Akt/mTOR pathway.

Herein, a derivate from tanshinone IIA, 1,6,6-trimethyl-11-phenyl-7,8,9,10-tetrahydro-6H-furo[2',3':1,2]phenanthro[3,4-d]imidazole (TA25), has been synthesized and investigated as potential inhibitor against the proliferation, migration and invasion of lung cancer cells. MTT assay and cell colony formation assay results showed that TA25 exhibits acceptable inhibitory effect against the proliferation of lung cancer A549 cells, and the value of IC50 was about 17.9 µM. This result was further confirmed by the inhibition of TA25 against the growth of xenograft lung cancer cells on zebrafish bearing tumor (A549 lung cancer cells). The results of wound-healing assay and FITC-gelatin invasion assay displayed that TA25 could inhibit the migration and invasion of lung cancer A549 cells. Moreover, the studies on the binding properties of TA25 interact with c-myc G-quadruplex DNA suggested that TA25 can bind in the G-quarter plane formed from G7, G11, G16 and G20 with c-myc G-quadruplex DNA through π-π stacking. Further study of the potential anti-cancer mechanism indicated that TA25 can induce S-phase arrest in lung cancer A549 cells, and this phenomenon resulted from the promotion of the production of reactive oxygen species and DNA damage in A549 cells under the action of TA25. Further research revealed that TA25 could inhibit the PI3K/Akt/mTOR signal pathway and increase the expression of p53 protein. Overall, TA25 can be developed into a promising inhibitor against the proliferation, migration and invasion of lung cancer cells and has potential clinical application in the near future.