Antitumor and Immunomodulatory Effects of Periplaneta americana Extract Combined With 5-Fluorouracil on Hepatocarcinoma Mice

Background and Objective: Periplaneta americana is an important traditional medicine in China. Moreover, Periplaneta americana is effective in treating multiple tumor types. Thus, this study aimed to investigate the combined effects of Periplaneta americana extract CII-3 (an active component from Periplaneta americana) and 5-fluorouracil (5-FU) on liver cancer in mice, focusing on anti-tumor and immunomodulatory properties. Materials and Methods: Mice were divided into five groups: normal, model, CII-3, 5-FU and 5-FU+CII-3. Continuous treatment for 14 days included monitoring tumor volume and weight, calculating spleen and thymus indices, and observing tumor tissue morphology. Immunological assays evaluated natural killer (NK) cell cytotoxicity, T/B lymphocyte proliferation, and the proportions of CD3+, CD4+, and CD8+ cells. ELISA was employed to assess serum levels of IgA, IgM, IgG, and interleukin-8 (IL-8). The reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were utilized to analyze the mRNA and protein expressions, respectively, of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), tumor necrosis factor receptor-associated factor 6 (TRAF6), myeloid differentiation primary response protein 88 (MyD88) and tumor necrosis factor-α (TNF-α) in tumors. Results: Compared to the 5-FU group, the 5-FU+CII-3 group showed reduced tumor mass and increased spleen and thymus indices. Tumor tissue in the treatment groups exhibited a loose structure, characterized by nuclear fragmentation and the presence of lipid vacuoles. The 5-FU+CII-3 group exhibited enhanced NK cell cytotoxicity, T/B lymphocyte proliferation, CD3+ proportion, CD4+/CD8+ ratio and serum levels of IgA, IgM, and IgG, alongside a reduction in IL-8 content. The levels of TLR4, NF-κB, MyD88, and TNF-α mRNA and protein expressions were downregulated, while TRAF6 mRNA expression was also notably decreased in the tumor tissue. Conclusion: The CII-3 and 5-FU combined treatment synergistically exerts anti-tumor and immunomodulatory effects, potentially mediated through the regulation of TLR4, NF-κB, TRAF6, MyD88, and TNF-α.