Omega-3 fatty acids from fish oil (FO) and selenium (Se) potentiate some conventional therapies and have anticancer immune potential. This study aims to determine whether FO/Se modulates G-protein-coupled polyunsaturated fatty acid receptors (GPR-40 and GPR-120) and selenoproteins (Sel-H, Sel-W, and GPx4), and increases the therapeutic effect of doxorubicin in a dose-dependent manner on triple-negative breast cancer (TNBC) mouse. Mice were randomized into 5 groups (n = 7/group) and treated with physiological saline (control), low-dose doxorubicin, and doxorubicin in combination with low, medium, or high doses of FO/Se. The expression of signaling molecules in tumors was determined by measuring either mRNA or protein expression. Compared with doxorubicin alone, combination treatment resulted in lower tumor sizes and fewer overall metastasis, lower GPR-40 mRNA levels, and higher expression of all selenoproteins. Doxorubicin-FO/Se combination treatment decreased expression of membrane EGFR and FGFR, down-regulated downstream PI3K/AKT/mTOR, MAPK/ERK, and JAK2/c-Src/STAT3 signaling, increased tumor suppressor PTEN/TSC1/TSC2 expression and P53 activation, and suppressed oncogenic transcription factor expression. Dose-dependent inhibition of proliferation index Ki-67, cell cycle, and stem-cell-related markers were observed. Decreased immune check-points PD-L1/CTLA-4/Foxp3/CD86 and increased PD-1/CD28/IL-2 expression was also found. These observations suggest that the nutritional supplements FO/Se increase the chemotherapeutic efficacy of doxorubicin against TNBC by modulating GPR-40 and selenoprotein and targeting multiple signaling pathways in tumor tissues.
Fish oil (FO) and selenium (Se) possess antiangiogenic potential in malignant tumors. This study aimed to determine whether combination of FO and Se enhanced treatment efficacy of low-dose antiangiogenic agent Avastin (bevacizumab) in a dose-dependent manner and targeted multiple signaling pathways in triple-negative breast cancer (TNBC)-bearing mice. Randomized into five groups, mice received treatment with either physiological saline (control), Avastin alone, or Avastin in combination with low, medium, and high doses of FO/Se. The target signaling molecules for anticancer were determined either by measuring protein or mRNA expression. Avastin-treated mice receiving FO/Se showed lower tumor growth and metastasis than did mice treated with Avastin alone. Combination-treated mice exhibited lower expressions in multiple proangiogenic (growth) factors and their membrane receptors, and altered cytoplasmic signaling molecules (PI3K-PTEN-AKT-TSC-mTOR-p70S6K-4EBP1, Ras-Raf-MEK-ERK, c-Src-JAK2-STAT3-TMEPAI-Smad, LKB1-AMPK, and GSK3β/β-catenin). Dose-dependent inhibition of down-stream targets including epithelial-to-mesenchymal transition transcription factors, nuclear cyclin and cyclin-dependent kinases, cancer stem cell markers, heat shock protein (HSP-90), hypoxia-inducible factors (HIF-1α/-2α), matrix metalloprotease (MMP-9), and increased apoptosis were observed. These results suggest that combination treatment with FO and Se increases the therapeutic efficacy of Avastin against TNBC in a dose-dependent manner through multiple signaling pathways in membrane, cytoplasmic, and nucleic targets.