Anticancer potentiating effect and downregulation of
<scp>PD‐L1</scp>
expression: Study on the 2‐[(
<i>p</i>
‐fluorophenyl)amino]‐
<scp>6‐substituted‐9</scp>
<i>H</i>
‐purine analogues as novel
<scp>CHK1</scp>
inhibitors
In this study, a series of 2-[p-fluorophenyl]-6-substituted-9H-purine analogues were designed and synthesized as CHK1 inhibitors, among which compound b22 was the most potent. b22 exhibited nearly no antiproliferative activity toward HT29 cells and displayed a significant antitumor potentiating effect on HT29 cells when treated in combination with gemcitabine (Gem). A time-dependent assay found that