Swimming attenuates tumor growth in CT-26 tumor-bearing mice and suppresses angiogenesis by mediating the HIF-1α/VEGFA pathway

Low physical activity correlates with increased cancer risk in various cancer types, including colorectal cancer (CRC). However, the ways in which swimming can benefit CRC remain largely unknown. In this study, mice bearing tumors derived from CT-26 cells were randomly divided into the control and swimming groups. Mice in the swimming group were subjected to physical training (swimming) for 3 weeks. Compared with the control group, swimming clearly attenuated tumor volume and tumor weight in CT-26 tumor-bearing mice. RNA sequencing (RNA-seq) identified 715 upregulated and 629 downregulated transcripts (including VEGFA) in tumor tissues of mice in the swimming group. KEGG pathway analysis based on differentially expressed transcripts identified multiple enriched signaling pathways, including angiogenesis, hypoxia, and vascular endothelial growth factor (VEGF) pathways. Consistently, IHC analysis revealed that swimming significantly downregulated CD31, HIF-1α, VEGFA, and VEGFR2 protein expression in tumor tissues. In conclusion, swimming significantly attenuates tumor growth in CT-26 tumor-bearing mice by inhibiting tumor angiogenesis via the suppression of the HIF-1α/VEGFA pathway.