In vitro cytotoxic activity of probiotic bacterial cell extracts against Caco-2 and HRT-18 colorectal cancer cells

S.S. Awaisheh1, M.M. Obeidat2, H.J. Al-Tamimi3, A.M. Assaf4, J.M. EL-Qudah1, J.M. Al-khaza’leh1, R.J. Rahahleh1

1 Food Microbiology and Safety Laboratory, Department of Nutrition and Food Processing, Faculty of Agricultural Technology- Balq´a Applied University, P.O. Box 19117, Salt, Jordan.
2 Department of Biotechnology, Faculty of Agriculturural Technology- Balq´a Applied University, P.O. Box 19117, Salt, Jordan.
3 Department of Animal Production, Faculty of Agriculture, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan.
4 Department of Biopharmaceutics and Clinical Pharmacy. Faculty of Pharmacy, The University of Jordan. Amman 11942, Jordan.

Date submitted: 22/02/2016    Date accepted: 14/04/2016    Volume/Page(s): 69/33-37

Abstract
This research aimed at screening the anti-cancer activity of cell extracts of forty potential probiotic bacterial isolates against 2 colorectal cancer (CRC) cell lines (namely, Caco-2 and HRT-18), and vero cells using 3-(4, 5-dimethylthiazolyl-2) -2, 5-diphenyltetrazolium bromide (MTT) and Trypan Blue assays (TBE). Results demonstrated that 2 isolates (Lactobacillus acidophilus LA102 and Lactobacillus casei LC232) showed pronounced cytotoxic activities, with proliferation inhibition of 37% and 68.5% of LA102, and 48% and 45.7% of LC232 against Caco-2 and HRT-18, respectively, at a concentration of 100 μg extract/ml. The IC50 values of the cytotoxic activity were 1.6 and 2.5 μg/ml of LA102, and 15.4 and 6.2 μg/ml of LC232 against Caco-2 and HRT-18, respectively. At the same time, results showed that LA102 and LC232 isolates had no cytotoxic effect on the normal vero cells.
Even though these observations raise the prospects of using these probiotic isolates for possible cancer prevention and even treatment, yet further investigation is needed to ascertain their potential to prevent in vivo human CRC.

Keywords: Probiotic; colorectal cancer; Lactic acid bacteria, Lactobacillus; MTT; cytotoxicity.