Lactobacillus acidophilus CICC 6074 inhibits growth and induces apoptosis in colorectal cancer cells in vitro and in HT-29 cells induced-mouse model

Abstract

• The first study of the anti-cancer mechanism of Lactobacillus acidophilus CICC 6074 was carried out. • L. acidophilus CICC 6074 exerts anticancer effects in HT-29 cell-induced colon cancer mouse model. • L. acidophilus CICC 6074 may induce HT-29 cell apoptosis through the mitochondrial pathway. • The research may provide theoretical basis for development of probiotics functional food market. This research sought to assess the anticancer effects of Lactobacillus acidophilus CICC 6074 and its underlying mechanism of action. L. acidophilus CICC 6074 inhibited HT-29 cell activity and induced its apoptosis in a dose- and time-dependent manner. HT-29 cells exposed to L. acidophilus CICC 6074 showed mitochondrial membrane potential (ΔΨm) loss, as well as Cyt c is released from the mitochondria into the cytoplasm, causing Bax, Caspase-9 and Caspase-3 to be up-regulated and Bcl-2 to be down-regulated. To further explore the mechanism by which L. acidophilus CICC 6074 achieves its anti-cancer effect, a HT-29 cell-induced colon cancer mouse model was used. Compared with a colon cancer model control group, the high-dose L. acidophilus CICC 6074 group showed obvious colon cancer cell apoptosis as measured by histological morphology, electron microscopy, and terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. An in vivo study showed that L. acidophilus CICC 6074 induced colon cancer apoptosis by up-regulating Bax, down-regulating Bcl-2, releasing Cyt c from the mitochondria into the cytoplasm, and activating Caspase-3 and Caspase-9. These results demonstrate that L. acidophilus CICC 6074 exerts anticancer effects via the activation of mitochondrial pathways which then induce apoptosis. The research could provide new ideas and theoretical basis for development of probiotics functional food market.