Published online Oct 28, 2023. doi: 10.3748/wjg.v29.i40.5543
Peer-review started: July 20, 2023
First decision: August 25, 2023
Revised: September 5, 2023
Accepted: October 11, 2023
Article in press: October 11, 2023
Published online: October 28, 2023
Processing time: 99 Days and 6.5 Hours
Phosphatidylinositol-3-kinases (PI3K) is a well-known route in inflammation-related cancer. Recent discovery on PI3K-related genes revealed a potential variant that links ulcerative colitis (UC) and colorectal cancer (CRC) with colitis-associated cancer (CAC). PI3K/AKT pathway has been recommended as a potential additional therapeutic option for CRC due to its substantial role in modifying cellular processes. Buparlisib is a pan-class I PI3K inhibitor previously shown to reduce tumor growth.
To investigate the regulation of rs10889677 and the role of buparlisib in the PI3K signaling pathway in CAC pathogenesis.
Genomic DNA from 32 colonic samples, including CAC (n = 7), UC (n = 10) and CRC (n = 15), was sequenced for the rs10889677 mutation. The mutant and wildtype fragments were amplified and cloned in the pmirGLO vector. The luciferase activity of cloned vectors was assessed after transfection into the HT29 cell line. CAC mice were induced by a mixture of a single azoxymethane injection and three cycles of dextran sulphate sodium, then buparlisib was administered after 14 d. The excised colon was subjected to immunohistochemistry for Ki67 and Cleaved-caspase-3 markers and quantitative real-time polymerase chain reaction analysis for Pdk1 and Sgk2.
Luciferase activity decreased by 2.07-fold in the rs10889677 mutant, confirming the hypothesis that the variant disrupted miRNA binding sites, which led to an increase in IL23R expression and the activation of the PI3K signaling pathway. Furthermore, CAC-induced mice had a significantly higher disease activity index (P < 0.05). Buparlisib treatment significantly decreased mean weight loss in CAC-induced mice (P < 0.05), reduced the percentage of proliferating cells by 5%, and increased the number of apoptotic cells. The treatment also caused a downward trend of Pdk1 expression and significantly decreased Sgk2 expression.
Our findings suggested that the rs10889677 variant as a critical initiator of the PI3K signaling pathway, and buparlisib had the ability to prevent PI3K-non-AKT activation in the pathophysiology of CAC.
Core Tip: The role of phosphatidylinositol-3-kinases (PI3K) in promoting cancer progression has been widely acknowledged due to its crucial involvement in regulating the survival, differentiation, and proliferation of cancer cells. Here, we investigate the role of PI3K signaling in colitis-associated cancer (CAC) pathogenesis by studying the regulation of potential variant in PI3K-related gene in the colorectal cancer cell line and the utilization of PI3K inhibitor, buparlisib, in the CAC-induced mice model. We suggested that rs10889677 variant plays a crucial role in initiating the PI3K signaling pathway, and buparlisib has the capability to inhibit PI3K-non-AKT activation in the pathophysiology of CAC.