Abstract: |
Recently, combining histone deacetylase (HDAC) inhibitors with chemotherapeutic drugs
or agents, in particular epidermal growth factor receptor (EGFR) inhibitors, is considered to be one
of the most encouraging strategy to enhance the efficacy of the antineoplastic agents and decrease
or avoid drug resistance. Therefore, in this work, based on introducing 3,4,5-trimethoxy phenyl
group as a part of the CAP moiety, in addition to incorporating 4–6 aliphatic carbons linker and
using COOH or hydroxamic acid as ZBG, 12 novel EGFR/HDAC hybrid inhibitors 2a–c, 3a–c, 4a–c
and 5a–c were designed, constructed, and evaluated for their anticancer activities against 4 cancer
cell lines (HepG2, MCF-7, HCT116 and A549). Among all, hybrids with hydroxamic acid 4a–c
and 5a, exhibited the highest inhibition against all cancer cell lines with IC50 ranging from 0.536
to 4.892 µM compared to Vorinostat (SAHA) with IC50 ranging from 2.43 to 3.63 µM and Gefitinib
with IC50 ranging from 1.439 to 3.366 µM. Mechanistically, the most potent hybrids 4a–c and 5a
were further tested for their EGFR and HDACs inhibitory activities. The findings disclosed that
hybrid 4b displayed IC50 = 0.063 µM on the target EGFR enzyme which is slightly less potent than
the standard Staurosporine (IC50 = 0.044 µM). Furthermore, hybrid 4b showed less HDAC inhibitory
activity IC50 against HDAC1 (0.148), 2 (0.168), 4 (5.852), 6 (0.06) and 8 (2.257) than SAHA
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