Ahead of Print | DOI: 10.14744/ejmo.2023.38981

B7-H3 Enhances Colorectal Cancer Progression by Regulating HB-EGF via PI3K-Akt-mTOR-HIF-1a Signaling

Chenrui Hu¹, Shengjia Wang², Xiaokang Ruan¹, Yonghao Liu³, Linwei Wu¹, Bingxin Chen⁴, Jin Wang⁵, Zhe Zhang⁶, Xin Zhao^7
1Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China, ²Jiangsu Institute of Clinical Immunology, The First Affiliated Hospital of Soochow University, Suzhou, China, ³Department of Radiology, The First Affiliated Hospital of Soochow University, Suzhou, China, ⁴Department of Gastroenterology, The First Affiliated Hospital of Soochow University, Suzhou, China, ⁵Department of General Surgery, Suzhou Dushu Lake Hospital (Dushu Lake Hospital Affiliated to Soochow University), Suzhou, China, ⁶Department of Biochemistry and Molecular Biology, School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, China, ⁷,

Objectives: B7-H3 (or CD276) represents an important costimulatory molecule expressed in many malignant solid tumors, including colorectal cancer. The receptor of B7-H3 is not known, and the intracellular function of B7-H3 remains obscure as well. Herein, we report that B7-H3 upregulated heparinbinding epidermal growth factor (HB-EGF), which is one of the epidermal growth factors, likely by regulating hypoxia factor 1? (HIF-1?) and thereby promoting the progression of colorectal cancer. Methods: A lentiviral transfection was performed on CRC cells to establish stable low- B7-H3 expression cells. Then a mechanistic analysis with an Agilent human gene expression profiling 4×44K chip was conducted. Results: We found B7-H3 mainly promoted tumor progression through HB-EGF and the PI3K-Akt pathway. As B7-H3 was downregulated and HB-EGF levels were significantly reduced simultaneously, both CRC cell lines and cancer tissues showed the same growth trend. In addition, B7-H3 and HB-EGF had significant associations with TNM stage and lymph node metastasis in 50 CRC patients. ChIP quantitative real-time PCR demonstrated the binding ability of HIF-1? to the HB-EGF promoter region was significantly decreased in the shB7-H3 RKO group, which indicates HIF-1? regulates HB-EGF as a transcription factor in CRC cells. We then recovered the HIF-1? level by lentiviral transfection, and HB-EGF mRNA levels, proliferation, invasion, and angiogenesis in CRC cells recovered as well. Western blot revealed that PI3K, AKT and mTOR protein amounts and p-AKT and p-mTOR phosphorylation were also significantly downregulated in shB7-H3 RKO cells, suggesting B7-H3 may regulate HIF-1? via PI3K-Akt signaling. Conclusion: B7-H3 may transmit intracellular signals through PI3K-AKTmTOR-HIF-1? signaling, upregulating HB-EGF. As the final transcription factor of the pathway, HIF-1? regulates the transcription of the HB-EGF gene, thereby promoting HB-EGF expression, which eventually mediates cell proliferation, invasion and angiogenesis and promotes the progression of colorectal cancer. Keyword: CRC; B7-H3; HB-EGF; HIF-1?; Agilent chip; ChIP;

---

Cite This Article

Hu C, Wang S, Ruan X, Liu Y, Wu L, Chen B, et al. B7-H3 Enhances Colorectal Cancer Progression by Regulating HB-EGF via PI3K-Akt-mTOR-HIF-1a Signaling. EJMO. ; (): -

Corresponding Author: Zhe Zhang