Evaluation of Indigo Naturalis Prepared Using a Novel Method: Anti-Inflammatory Activities Against Colonic Cancer...

Area of Science:

• Gastroenterology
• Molecular Biology
• Cancer Research

Background:

• Ulcerative colitis (UC), a chronic inflammatory bowel disease (IBD), carries a significant risk of cancerous transformation linked to persistent colonic inflammation.
• Indigo naturalis (IN), particularly a novel preparation (NIN), shows promise against inflammatory and cancerous colonic cells, but its mechanism requires elucidation.

Purpose of the Study:

• To investigate the effects of NIN on an inflammatory cancer model using HT-29 colonic cancer cells.
• To elucidate the underlying molecular mechanisms by which NIN impacts inflammation and cancer progression in the colon.

Main Methods:

• Constructed an in vitro inflammation model using the HT-29 colonic cancer cell line.
• Administered NIN to the model and assessed changes in pro-inflammatory cytokines (IL-1β), mucin production (MUC2), and cell proliferation.
• Investigated the involvement of aryl hydrocarbon receptor (AhR) and Wnt/β-catenin signaling pathways, including key gene expressions (Rnf43, β-catenin, Axin2, Lgr5).
• Utilized an AhR antagonist (CH223191) to confirm pathway involvement.

Main Results:

• NIN reduced elevated IL-1β expression and attenuated inflammatory responses.
• NIN increased MUC2 expression, restoring mucin secretion, and inhibited HT-29 cell proliferation.
• NIN activated the AhR signaling pathway, leading to increased Rnf43 expression and decreased nonphosphorylated β-catenin and Axin2 levels.
• This activation inhibited the Wnt/β-catenin pathway and reduced Lgr5 expression, a colorectal cancer stem cell marker.
• The effects of NIN were blocked by the AhR antagonist CH223191, confirming AhR pathway mediation.

Conclusions:

• NIN effectively alleviates ulcerative colitis-associated inflammation and cancer progression in vitro.
• The mechanism involves NIN activating the AhR signaling pathway, which subsequently inhibits the Wnt/β-catenin signaling pathway.
• These findings provide insights into the inflammation-cancer transformation process in UC and highlight NIN as a potential therapeutic agent.