Cytotoxicity of Probiotics from Philippine Commercial Dairy Products on Cancer Cells and the Effect on Expression of cfos and cjun Early Apoptotic-Promoting Genes and Interleukin-1β and Tumor Necrosis Factor-α Proinflammatory Cytokine Genes

This study determined cytotoxicity of probiotic Lactobacillus spp. from Philippine dairy products on cancer cells and normal fibroblasts and their effects on expression of early apoptotic-promoting cfos, cjun and proinflammatory cytokine IL-1β, TNF-α genes. Cultures were from Yakult, Bear Brand Probiotic Drink, Nido3+ Powdered Milk. Filter-sterilized supernatants from cultures of Lactobacillus spp. were evaluated for cytotoxicity to colon cancer cells (HT-29 and HCT116), leukemia cells (THP-1), and normal human dermal fibroblasts (HDFn) using PrestoBlue. Bleomycin was the positive control. Absolute quantification of transcript levels was conducted using qRT-PCR. Cytotoxicity index profiles on HDFn, THP-1 of all probiotic supernatants and negative controls suggest nontoxicity to the cells when compared to bleomycin, whereas all probiotic supernatants were found to be cytotoxic to HT-29 and HCT-116 colon cancer cell lines. Expression of cfos, cjun transcripts was significantly upregulated in HT-29 and HCT116 cells treated with probiotic supernatants compared to untreated baseline levels (P < 0.05). Expression of IL-1β and TNF-α by lipopolysaccharide-treated macrophages was significantly downregulated in cells with probiotic supernatants compared to those exposed to MRS medium (P < 0.05). Results provide strong support for the role of Lactobacillus spp. studied in anticancer therapy and in prevention of inflammation that may act as precursor to carcinogenesis.