Investigating the Effects of Lactobacillus Plantarum Strain ATCC 8014 on Gene Expression of NF-ĸB, TLR-4, and BCL-2 in Oral Rat Cancer Induced by 4-Nitroquioline 1-Oxide

Oral cancer relates to oral and intestinal microbiota composition. Lactobacillus species are considered probiotic bacteria due to their ability to modulate human immune responses and therapeutic effects. This study aimed to investigate the effects of Lactobacillus plantarum (L. plantarum) on TLR4 gene expression and its downstream pathways in a mouse model of oral cancer.

This experimental study was conducted in the Stem Cell Research Center, Faculty of Modern Technologies, Golestan University of Medical Sciences, Gorgan, Iran, in 2021. L. plantarum strain ATCC 8014 was used in this study. Twenty-eight male Wistar rats were divided into four groups (n = 7). 4-Nitroquinoline 1-oxide (4NQO) was used to establish oral cancer in rats. A pathological examination was adopted to confirm cancer establishment. Rats were treated with probiotic L. plantarum before and after cancer development. After extracting RNA from blood and synthesizing cDNA, the ability of lactobacilli to modulate the expression of TLR4 genes was investigated by Real-Time PCR Methods (RT-PCR).

In the present study, it was observed that after causing cancer and treating the animal with L. plantarum, the expression of the TLR4 gene decreased significantly (P-value < 0.05), which might, in turn, affect the downstream pathways, which included the decrease in the expression of BCL-2 and NF-ĸB genes. Accordingly, the expression of the NF-ĸB gene was significantly reduced in rats received L. plantarumgavaged for two weeks after cancer induction.

According to the obtained results, probiotic L. plantarum significantly affects the gene expression of NF-ĸB and TLR4 in cancerous rats. It was also shown that L. plantarum was more efficient in reducing TLR-4 and NF-ĸB genes expression when it was gavaged for 14 days after tumor induction.