Shen-Qi-Ling-Bi Decoction Inhibits Colorectal Cancer Cell Growth by Inducing Ferroptosis Through Inactivation of PI3K/AKT Signaling Pathway

Colorectal cancer (CRC) is a common malignancy with poor prognosis. Shen-Qi-Ling-Bi Decoction (SQLB), a classic traditional Chinese medicine (TCM) formula, was found to exert antitumor effects in CRC. This study aimed to explore the biological functions of SQLB in CRC. Cell Counting Kit 8 (CCK-8), wound healing, and transwell invasion assays in vitro were used to evaluate the antitumor effects of SQLB in CRC cells. In addition, ferroptosis in CRC cells was determined by evaluating Fe²⁺ content and lipid ROS, MDA, and GSH levels. SQLB treatment partially reduced CRC cell proliferation, migration, and invasion; however, a ferroptosis inhibitor, ferrostatin-1 (Fer-1), abolished these effects. In addition, SQLB treatment triggered CRC cell ferroptosis, as evidenced by increased Fe²⁺, lipid ROS, and MDA levels and decreased GSH levels; conversely, these levels were reversed by Fer-1. Furthermore, SQLB notably suppressed tumor growth in nude mice in vivo. Meanwhile, SQLB decreased phosphorylated PI3K and AKT levels, downregulated Nrf2, GPX4, and SLC7A11 levels, and upregulated ACSL4 levels in CRC cells and in tumor tissues; however, these effects were reversed by Fer-1. Collectively, SQLB inhibited CRC cell proliferation, invasion, and migration by triggering ferroptosis through inactivation of the PI3K/AKT signaling pathway. These findings demonstrate a novel mechanism of action for SQLB in the treatment of CRC.