The mechanism of anticancer effects of some pyrrolopyrimidine derivatives on HT-29 human colon cancer cells
Abstract
In the present work, the mechanism of anticancer activity of some pyrrolopyrimidine derivatives was evaluated.
Compounds 5 and 8 exhibiting significant antiproliferative activity against HT-29 cells with IC50 values of 4.17
μM and 2.96, arrested the cells at the G2/M phase and significantly induced apoptosis. The apoptotic potential of
the compounds has been verified via ELISA assay, which resulted in increased BAX, PUMA, BIM, and cleaved
caspase 3 expression and decreased BCL-XL and MCL-1 protein levels in HT-29 cells. Moreover, the immuno fluorescence technique showing that compounds 5 and 8-treatment reduced Ki67 immunolocalization and
increased the caspase 3 and p53 immunolocalization confirmed the apoptotic activity. While treatment of HT-29
cells to compounds 5 and 8 inhibited Akt and ERK1/2, there are no alterations in JNK and p38 signaling
pathways. According to molecular docking results, compounds 5 and 8 occupied the active site of Akt kinase and
showed important hydrogen bonding interactions with key amino acids. Also, siRNA-mediated depletion of BIM,
PUMA, and BAX/BAK expression decreased apoptotic response in HT-29 cells upon exposure to compound 5 and
compound 8. Compounds 5 and 8 trigger the activation of mitochondrial apoptosis in HT-29 cells. Additionally,
we found that proapoptotic BH3-only proteins BIM and PUMA are required for the full engagement of mito chondrial apoptosis signaling. However, p53 was dispensable for compound 5- or compound 8-induced apoptosis
in HT-29 cells.