Cis-9, Trans-11 Conjugated Linoleic Acid Promotes Apoptosis, Restores OxidativeHomeostasis and Inhibits the Proliferation of Canine Mammary Tumor Cells

Canine mammary tumors (CMTs), one of the most common malignant neoplasms in female dogs, currently lack effective chemotherapeutic options beyond surgical treatment.Conjugated linoleic acid (CLA), particularly the cis-9, trans-11 CLA (c9, t11-CLA) isomer, has demonstrated anticancer potential in human studies; however, its specific mechanisms in CMTs remain largely unexplored.This study investigated the antitumor effects of c9, t11-CLA on the CMT cell line CMT-U27, focusing on apoptosis regulation and oxidative stress modulation, thereby providing the theoretical basis for developing novel anti-tumor therapies.Following treatment of the CMT-U27 cells with various concentrations of c9, t11-CLA, CCK-8 assays revealed a concentration-dependent increase in apoptosis.Quantitative RT-qPCR and western blot analyses were performed to assess the 120M, the expression of the antiapoptotic proteins (Bcl-2 and Bcl-XL) was significantly decreased (P<0.05), while the expression of proapoptotic proteins (Bax and Bad) increased (P<0.05).Additionally, catalase expression was reduced (P<0.05), the malondialdehyde content was increased, and superoxide dismutase activity was decreased.In summary, this study demonstrates that c9, t11-CLA treatment significantly inhibits the proliferation of CMT-U27 cells, potentially through modulation of Bcl-2 family protein expression, activation of peroxisome proliferator-activated receptor gamma (PPAR), and disruption of the oxidative homeostasis.