ADH1C Down-Regulation Is a Key Hypoxia Response in Colon Epithelium.

Area of Science:

• Cell Biology
• Gastroenterology
• Cancer Research

Background:

• Colorectal cancer (CRC) often involves hypoxia, yet normal colon epithelial responses to oxygen changes are poorly understood.
• Physiologic hypoxia and ischemic injury susceptibility are characteristic of colon mucosa.

Purpose of the Study:

• To investigate adaptive responses of normal human colon epithelial cells to sustained hypoxia.
• To identify molecular mediators of colon epithelial adaptation to hypoxia and their relevance to CRC.

Main Methods:

• Human colon organoids (colonoids) were cultured under sustained hypoxia.
• Phenotypic and transcriptional changes were characterized.
• Alcohol dehydrogenase 1C (ADH1C) expression was analyzed in colonoids and archival patient tissues.

Main Results:

• Sustained hypoxia led to robust downregulation of ADH1C in colonoids, validated in ischemic colitis tissues.
• ADH1C downregulation was linked to reduced reactive oxygen species (ROS) and increased NADPH under hypoxia.
• Hypoxia-induced ADH1C reduction altered cell signatures, decreasing transit-amplifying (TA) cell markers and increasing stem cell marker FGFBP1.
• ADH1C-low colorectal cancer (CRC) tissues showed enrichment for hypoxia-associated signatures compared to ADH1C-high CRC.

Conclusions:

• Alcohol dehydrogenase 1C (ADH1C) acts as a key mediator of colon epithelial responses to hypoxia.
• ADH1C downregulation facilitates ROS neutralization and influences epithelial cell identity during hypoxia.
• These findings highlight ADH1C's role in colon epithelial adaptation and its significance in colorectal cancer development.