The College of Pharmacy discussed the MSc thesis entitled “In-Silico Studies, Synthesis, and Preliminary Cytotoxicity Evaluation of New Thiazoline Thioether” by the student Heba Hashim Khaleel and the supervisor, Assistant Professor Dr. Ayad Abed Ali Al-Hamashi, at the Pharmaceutical Chemistry Department.
The study aimed to develop new HDAC inhibitors using a thiazoline as a possible zinc-binding component, since the inhibition of HDAC enzymes has emerged as a promising strategy for cancer therapy.
The study included the structure-based design of a series of thiazoline-based compounds. These compounds were virtually evaluated through molecular docking and prediction of their pharmacokinetic properties, alongside Vorinostat as a reference compound. The final compounds exhibiting the most favorable docking results were selected for chemical synthesis. The synthetic pathway commenced with the formation of a thioether linkage between ethyl 4-(chloromethyl) benzoate and 2-thiazoline-2-thiol via a Williamson-type reaction, yielding ethyl 4-(((4, 5-dihydrothiazol-2-yl) thio) methyl) benzoate. Subsequent hydrolysis with sodium hydroxide afforded 4-(((4, 5-dihydrothiazol-2-yl) thio) methyl) benzoic acid. An amide coupling reaction between the resulting acid and various amine derivatives was then carried out to obtain the final compounds. The synthesized compounds were purified using CombiFlash chromatography and characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and mass spectrometry (MS). Their cytotoxic activities were evaluated against colorectal cancer and lung cancer cell lines in comparison with Vorinostat as the reference compound.
The results showed that preliminary biological evaluation against colorectal cancer cells revealed that compound 7, containing a para-trifluoromethyl phenyl moiety with strong electron-withdrawing and lipophilic properties in the cap region, exhibited significant cytotoxic activity, with an IC50 value of 10.14 μM. This value was approximately 46-fold higher than that of Vorinostat (0.22 μM). When tested against cervical cancer cell lines, compound 7 displayed an IC50 value of 8.5 μM, which was comparable to that of Vorinostat (5.33 μM). Interestingly, compound 7 demonstrated a selective cytotoxic profile, showing no detectable cytotoxicity against lung cancer cells.
The study recommended further structure–activity relationship (SAR) investigations, as well as in vitro HDAC inhibition assays to evaluate the potency and selectivity of enzymatic inhibition. Additionally, expanding anti proliferative studies to include a broader range of cancer cell lines was recommended to further assess the cytotoxic potential of the synthesized compounds. Furthermore, in vivo studies using tumor-bearing animal models are warranted to provide a more comprehensive and accurate evaluation of their anticancer activity.
