Anti-tumour immune effect of oral administration of Lactobacillus plantarum to CT26 tumour-bearing mice

Abstract

Colorectal cancer (CRC) is one of the most prevalent forms of cancer that shows a high mortality and increasing incidence. There are numerous successful treatment options for CRC, including surgery, chemotherapy, radiotherapy and immunotherapy; however, their side effects and limitations are considerable. Probiotics may be an effective strategy for preventing and inhibiting tumour growth through stimulation of host innate and adaptive immunity. We investigated and compared potential anti-tumour immune responses induced by two isolated Lactobacillus strains, Lactobacillus plantarum A and Lactobacillus rhamnosus b, by pre-inoculating mice with lactobacilli for 14 days. Subsequently, subcutaneous and orthotopic intestinal tumours were generated in the pre-inoculated mice using CT26 murine adenocarcinoma cells and were assessed for response against the tumour. Our results indicated that oral administration with L. plantarum inhibited CT26 cell growth in BALB/c mice and prolonged the survival time of tumour-bearing mice compared with mice administered L. rhamnosus. L. plantarum produced protective immunity against the challenge with CT26 cells by increasing the effector functions of CD8+ and natural killer (NK) cell infiltration into tumour tissue, up-regulation of IFN-gamma (but not IL-4 or IL-17) production, and promotion of Th1-type CD4+ T differentiation. Consequently, our results suggest that L. plantarum can enhance the anti-tumour immune response and delay tumour formation.

The Effect of <i>Lactobacillus Plantarum </i>and Bacterial Peptidoglycan on the Growth of Mouse Tumors <i>in vivo</i> and <i>in vitro</i>

“…Decreased levels of VEGF and increased levels of IL-12 at different time intervals in tumor-bearing mice treated with Lp, as compared to untreated controls, supports the anti-tumor effect of Lp. This anti-tumor effect is consistent with the findings reported by previous studies; Hu et al (2015) evaluated tumor size and demonstrated that Lp significantly inhibited CT26 growth, while Murosaki et al (2000) reported that the anti-tumor effects of heat-killed Lp is through restoration of impaired interleukin-12 production in tumorbearing mice. It can be speculated that receptors expressed by several IL-12-producing cells (such as macrophages, neutrophils and dendritic cells), are engaged by Lp resulting in signal transmission, activation of transcription factors and production of cytokines including IL-12.…”

“…Lp, a normal member of the intestinal and vaginal flora, was used to treat colorectal cancer in mice. It was reported that the anti-colorectal cancer effect of Lp is attributed to its ability to enhance the immune response against cancer cells (Hu et al, 2015). Based on these results, treatment of melanoma-bearing mice with Lp was attempted.…”

“…It has been reported that Lactobacilli can induce differentiation to Th1 immune response, which is important for tumor inhibition (Hu et al, 2015). Previous studies in mice showed that administration of L. acidophilus and Lp modulate the immune response against breast cancer and colorectal cancer, respectively (Maroof et al, 2012;Hu et al, 2015).…”

The Role of Probiotics in Colorectal Cancer Management

“…Hu et al [42] studied the effect of probiotic strains (L. plantarum or L. rhamnosus) in CT26 tumor-bearing BALB/c mice. BALB/c mice were presupplemented with L. plantarum or L. rhamnosus (1 × 10 9 CFU/day) for 14 days and CT26 carcinoma cells were introduced to induce cancer in mice.…”

Probiotic Characterization of Lactic Acid Bacteria Isolated From Local Fermented Vegetables (Makdoos)

“…Studying Lactobacillus strains isolated from fermented vegetables recorded much lower adhesion values ranging from 0.45 -12.27 % in most cases, it is believed that variations are strain specific and is linked to differences in cell surface structures (Garcia-Ruiz et al, 2014;Hu et al, 2015). Finally, taking all of the above results in consideration, it is clear that traditionally fermented FOODS and vegetables and Makdoos in this case presents a promising source of improved probiotic lactobacilli due to stresses exerted upon the bacteria during the course of ripening of the mix of fermented vegetables.…”