Dual-Protein Intervention in CT26 Tumor-Bearing Mice: A Preliminary Evaluation of Its Effects on Anti-Tumor Efficacy of 5-Fluorouracil and Immune Responses

Background: Colorectal cancer is a common malignancy and 5-fluorouracil (FU) remains a mainstay of chemotherapy despite its toxicity. As an important part of comprehensive tumor treatment, dual-protein (DP) nutritional intervention is attracting more and more attention. Methods: This study preliminarily evaluated the regulatory effects of DP intervention on colorectal cells of CT26 tumor-bearing mice, examining the dosage and administration methods of DP, as well as the anti-tumor effects of FU alone or in combination with DP. Results: The results showed that low- and medium-dose DP numerically increased spleen index and showed trends toward alleviating FU-induced thymic atrophy, splenic damage, nephrotoxicity, and myocardial injury. It also partly mitigated muscle wasting, prevented FU-induced shortening of the colorectal tract, and reduced intestinal injury. In addition, DP was associated with increased lymphocyte, monocyte, and platelet counts and decreased granulocytes, suggesting possible alleviation of chemotherapy-induced bone marrow suppression and a potential effect on hematopoietic function. Flow cytometry results indicated possible effects of DP on CD4+ T and CD8+ T cell proliferation or apoptosis, modulation of effector and memory phenotypes, reduced splenic neutrophil levels, balanced B cell function, and maintained natural killer cell activity. In addition, DP intervention also showed trends toward regulating hepatic lipid metabolism and partially alleviating FU-induced dyslipidemia and muscle damage. In addition, DP and FU could increase IL-2, IL-10, GM-CSF and IFN-γ and decrease IL-6 and TNF-α. Conclusion: In conclusion, a moderate dose (0.67 g/kg) of DP had the most favorable trends, and the pre-intervention mode was more effective. This study also provided exploratory data on the potential of DP in reducing chemotherapy-related toxicity. These findings will provide preliminary scientific support for nutritional therapy in colorectal cancer patients, as well as for the research, development, and application of dual-protein foods for special medical purposes.