The Role of Hypoxia-Induced Tumor-Associated Macrophages in Regulating miR-320/SOX4 Axis and ER Stress in Colorectal Cancer Cells

Yuqing Kang^#, Jiangbo Zheng^#, Chunyan Mou^#, Ranxu Lv, Xing Xue^*
Department of Anesthesiology, Jinshan Branch of Shanghai Sixth People’s Hospital, Shanghai, China
* Corresponding Author: Xing Xue. Email: email
# These authors contributed equally to this work
(This article belongs to the Special Issue: Advanced Cell Signaling Pathways in Health and Disease)

BIOCELL https://doi.org/10.32604/biocell.2026.081318

Received 27 February 2026; Accepted 16 June 2026; Published online 13 July 2026

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Abstract

Objectives: Tumor-associated macrophages (TAMs) within the hypoxic tumor microenvironment critically drive colorectal cancer (CRC) progression, yet their specific regulatory mechanisms on endoplasmic reticulum (ER) homeostasis via microRNAs remain understood. This study aims to assess the impact of hypoxia-induced TAMs on CRC cells through the microRNA-320 (miR-320)/SRY-box transcription factor 4 (SOX4) axis, focusing on ER homeostasis and malignant behaviors. Methods: Human CRC cell lines HCT116 and SW480 were co-cultured with hypoxia-induced macrophages. Cells were treated with miR-320 mimics and inhibitors to evaluate proliferation and apoptosis using Cell-counting kit-8 (CCK8) assays and flow cytometry. Western blotting was performed to detect ER stress-related proteins. Dual-luciferase assays were conducted to confirm SOX4 as a target of miR-320. Results: Hypoxia-induced macrophages significantly downregulated miR-320 expression in CRC cells (by up to 45%). miR-320 mimics decreased CRC cell proliferation and increased apoptosis (with an absolute rate increase of 6.0–8.5%), while inhibitors had the opposite effect. Western blot analysis showed that miR-320 mimics promoted ER stress markers, upregulating the levels of phosphorylated eukaryotic translation initiation factor 2 subunit alpha (p-EIF2α), DNA damage inducible transcript 3 (DDIT3), and activating transcription factor 6 (ATF6) by 2- to 3-fold. MiR-320 directly targeted SOX4, suppressing its mRNA expression by over 70%, to inhibit tumor cell malignant behavior. The miR-320/SOX4 axis modulated proliferation and ER stress, with SOX4 overexpression significantly reversing the apoptotic and stress-inducing effects of miR-320 mimics on CRC cells. Conclusion: Hypoxia-induced macrophages in the tumor microenvironment modulate CRC progression via the miR-320/SOX4 axis, influencing ER homeostasis and cell proliferation. These findings highlight potential therapeutic targets for CRC treatment strategies, aiming to improve clinical outcomes.