Acidified Bile Acid-Induced ROS Facilitates Stemness and Proliferation of Gastric Cancer Cells

Ke Zhai, Guodong Liu, Xiaoping Yang and Xiaolong Wang

Background and Objective: Acidified bile acids facilitate the growth of gastric cancer (GC) by cancer Myelocytomatosis (c-Myc). Reactive oxygen species (ROS) produced during oxidative stress in the body are closely related to tumor development, so the research aims to elucidate whether acidified bile acids regulate GC progression in a ROS-dependent manner. Materials and Methods: The GC cells were exposed to bile salts (100 μM chenodeoxycholic acid and deoxycholic acid) in acidic medium (pH = 5.5) for 10 min per day over 60 weeks to mimic the acidified bile acid environment in vitro. Cell proliferation and stemness were estimated by 5-ethynyl-2'-deoxyuridine and sphere-forming assays. Some genes were analyzed at the mRNA or protein levels by reverse transcription-quantitative polymerase chain reaction and western blotting. The ROS production and telomerase activity were detected by the fluorescence probe dihydroethidium and telomere repeat amplification protocol. Elimination of ROS was performed with N-acetyl-L-cysteine (NAC) to evaluate the function of ROS. Results: Acidified bile acids facilitated GC cell proliferation and stemness, accompanied by increased protein levels of PCNA, Oct4 and CD44. Acidified bile acids induced ROS production, along with elevated mRNA levels of Telomerase Reverse Transcriptase (TERT), protein levels of c-Myc and telomerase activity. The NAC treatment reversed acidified bile acids-mediated effects on the proliferation, stemness and ROS production of GC cells, with accompanying changes in TERT mRNA levels, c-Myc protein levels and telomerase activity. Conclusion: Acidified bile acids enhanced telomerase activity through c-Myc in a ROS-dependent manner, thereby contributing to GC cell proliferation and stemness.

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