Anticancer potential against cervix cancer (HeLa) cell line of probiotic Lactobacillus casei and Lactobacillus paracasei strains isolated from human breast milk

Abstract

Lactic acid bacteria have been categorized as probiotics and play a crucial role in human health by stimulating the supply of nutrients, shaping the immune system, and preventing the colonization of pathogenic microbes. This study investigated the mechanisms for the action of three potential probiotic Lactobacillus strains: Lactobacillus casei SR1, Lactobacillus casei SR2, and Lactobacillus paracasei SR4 isolated from human breast milk. These Lactobacillus strains were identified via 16S DNA sequencing and characterized via biochemical assays including acid resistance, bile resistance, antioxidant activity, and antibiotic susceptibility. The bioactivity of the cell-free culture supernatant (CFCS) secreted by these strains on the cervix cancer (HeLa) cell line was also evaluated via cytotoxicity assay and apoptosis analysis. The mechanism of anticancer activity was also investigated via RT-qPCR and western blotting. The results demonstrated that these newly isolated Lactobacillus strains from human milk displayed noticeable probiotic characteristics such as excellent antibiotic susceptibility, outstanding antioxidant activity, and promising resistance to low pH and high concentration of bile salts. The results of the conducted bioactivity assays verified that the CFCSs had acceptable anticancer effects on cervix cancer (HeLa) cells by upregulating the expression of apoptotic genes BAX, BAD, caspase3, caspase8, and caspase9 and by downregulating the expression of the BCl-2 gene. Overall, these results indicate that the Lactobacillus strains isolated from human breast milk could be considered as a topical medication with a potential therapeutic index due to their efficacy against cervix cancer cells.

Changes Over the Fermentation Period in Phenolic Compounds and Antioxidant and Anticancer Activities of Blueberries Fermented by Lactobacillus plantarum

“…Western blotting for the detection of apoptosis‐related proteins also revealed that the population of apoptotic cells and the cleaved forms of caspase‐9 and PARP were markedly increased in cells treated with the 3‐day FBE, more than those treated with 7‐day FBE (Figure D). The degree of apoptosis caused by FBE did not depend on the fermentation time of the treated blueberries, which can be explained by the fact that probiotic lactobacillus strains themselves could inhibit proliferation and induce apoptosis in cervical cancer cells (Rajoka et al., ). In our study, lactobacillus growth was most prominent on the third day of blueberry fermentation, and the apoptosis of HeLa cells was also increased most when treated with 3‐day FBE.…”

Modulation of JNK-1/ β-catenin signaling byLactobacillus casei, inulin and their combination in 1,2-dimethylhydrazine-induced colon cancer in mice

“…62 Importantly, it was previously found that certain Lactobacillus strains isolated from human breast milk could combat cervical cancer via inducing apoptosis and inhibiting proliferation. 63 In particular, L. casei potentiated the antiproliferative effect of geniposide through the production of b-glucosidase in oral squamous cell carcinoma. 64 Remarkably, the anti-cancer activity of inulin was previously elucidated against melanoma as well as the transplanted mammary tumors in rats.…”

Immune Responses Raised in an Experimental Colon Carcinoma Model Following Oral Administration of Lactobacillus casei

“…Several in vitro experiments have revealed that probiotic bacteria demonstrate cytotoxicity against human cancer cell lines [13,14]. Viable bacteria, metabolites [15] and cell free extracts [16] have been proposed as anti-proliferative agents.…”