Role of Native Probiotic Lactobacillus Species via TGF-β Signaling Pathway Modulation in CRC

Sepehr, Amin; Aghamohammad, Shadi; Ghanavati, Roya; Talebi, Malihe; Pourshafie*, Mohammad Reza; Rohani, Mahdi

doi:10.61186/ibj.4012

Role of Native Probiotic Lactobacillus Species via TGF-β Signaling Pathway Modulation in CRC

Authors

Amin Sepehr ¹

Shadi Aghamohammad ¹

Roya Ghanavati ²

Malihe Talebi ³

Mohammad Reza Pourshafie* ¹

Mahdi Rohani ¹

¹ Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran

² Behbahan Faculty of Medical Sciences, Behbahan, Iran

³ Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran

10.61186/ibj.4012

Abstract

Background: Colon microbiome composition in colorectal cancer (CRC) patients undergoes remarkable changes. The present study was designed to assess the impact of Lactobacillus mixture on the regulating the CRC by influencing the transforming growth factor beta (TGF-β) signaling pathway in both in vitro (HT-29 cancer cells) and in vivo (BALB/c mice) models.

Methods: In this study, the antiproliferative effect of a native potential probiotic Lactobacillus mixture on HT-29 cancer cells was evaluated using the MTT assay method. Also, qRT-PCR was performed to assess the RNA expression level of genes associated with the TGF-β signaling pathway at three levels: receptor, regulatory, and inhibitory SMADs. Finally, the in vivo assays were investigated by three groups of mice: a naive group (PBS), a disease group (azoxymethane [AOM]/ dextran sulfate sodium [DSS] + PBS), and a treatment group (AOM/DSS + Lactobacillus mixture in PBS).

Results: The MTT results showed a significant decrease in proliferation of HT-29 cancer cells after 120 h of treatment. Furthermore, qRT-PCR demonstrated the downregulation of the smad2/3 gene expression in HT-29-treated cells and also reduction in the level of smad4 gene expression. In addition, in the mouse model, the tgf-βR1 gene was downregulated in the group treated with AOM/DSS/Lactobacillus, but not the AOM/DSS group. A downregulation of smad4 gene expression was also observed in in vivo models.

Conclusion: The obtained results suggest that our novel probiotic Lactobacillus mixture could have a positive impact on the inhibition of the CRC progression by downregulating the TGF-β signaling pathway.

Keywords

Colorectal cancer

Lactobacillus

Probiotics

TGF-β