Design and Synthesis of Novel Thiazolo[5,4-d]pyrimidine Derivatives as Potential Angiogenesis Inhibitors

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 μM) comparable to sunitinib (IC50  = 0.100 μM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Pharmacological Evaluation of Novel 1,2,4-triazine Derivatives Containing Thiazole Ring against Hepatocellular Carcinoma

Background:

New 6-hydroxy-5-(p-hydroxybenzylidene)-3-phenyl-2- [(5-pchlorophenyl)- 1,3-thiazol-2-yl]-1, 2, 4-triazine derivatives containing a thiazole ring were synthesised as potential antitumor agents.

Methods:

Cytotoxicity of compounds (3) and (4) was evaluated in human hepatocellular carcinoma (HCC) cell lines (HepG2); compound (3) showed more cytotoxicity (IC50=9.0μg/ml) than compound (4) (IC50=18.40μg/ml) using doxorubicin as standard. The degree of toxicity of compound (3) was assessed by the LD50 with its anticancer performance by suppressing tumor angiogenesis against diethylnitrosamine (DENA) induced hepatocellular carcinoma (HCC) in male rat model.

Results :

Carcinogenic rats showed a significant increase in markers of angiogenesis, tumour growth, and liver function tests and malondialdehyde level coupled with reduced hepatic glutathione level and caspase-3 activity. The distribution of compound (3) to animals after the development of HCC improved biochemical alterations from a DENA chemical carcinogen that is confirmed by hepatic histopathology.

Conclusion:

Compound 3 perhaps utilized as a strong applicant for newly therapeutic protocols against hepatocarcinogenesis by controlling tumor angiogenesis and renovating the activity of hepatic marker enzymes in addition to reversing the oxidant-antioxidant imbalance in corporation with amelioration of histopathology. While the trial supports the use of compound 3 for improved HCC outcome and the toxicity and side effects should be considered.