Bioprophylactic potential of novel human colostrum probiotics via apoptotic induction of colon cancer cells and cell immune activation

The potential and modes of action of novel human colostrum probiotics were investigated with the aim of studying their application as an alternative in the bioprophylactic and biotherapy of colon cancer. A total of 218 isolates of Gram-positive rod and cocci bacteria obtained from the colostrum of 50 healthy lactating females were collected. Beneficial probiotic criteria from these isolates, which included growth inhibition against seven foodborne pathogens (Helicobacter pylori, Escherichia coli, Salmonella Enteritidis, Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes), no blood haemolysis and tolerance to acid and bile salt conditions, resulted in only eight probiotic bacteria successfully inhibiting the proliferation of colon cancer cells at rates of 32.47-61.21%. Two probiotic bacteria with higher anticancer efficacy (Streptococcus salivarius CP163 and S. salivarius CP208) were identified using 16S rRNA sequences. High rates of cell surface hydrophobicity, autoaggregation and coaggregation were obtained from both probiotics. The probiotic mode of action involved synergic probiotic adhesion to colon cancer cells that triggered SCFA bioproduction. Apoptotic induction of colon cancer cell death through caspase-2 activity, DNA fragmentation and morphological change as assessed by AO/PI staining were also observed. Immune stimulation by S. salivarius CP163 and S. salivarius CP208 resulted in B and T-cell lymphocyte activation. This study suggests that these novel human colostrum probiotics could be applied as a functional food to facilitate a bioprophylactic strategy in colon cancer.