Salmonella reduces tumor metastasis by downregulation C-X-C chemokine receptor type 4

Salmonella-induced inhibition of β3-adrenoceptor expression in tumors and reduces tumor metastasis

The β3-adrenoceptor is a protein responsible for regulating the body's response to the neurotransmitter adrenaline and the hormone norepinephrine. It is critical in various physiological processes, including metabolism, thermogenesis, and cardiovascular function. Recently, researchers have discovered that the β3-adrenoceptor is also implicated in tumor progression and metastasis. Infections caused by Salmonella can lead to gastroenteritis; however, intriguingly, Salmonella is associated with tumor inhibition. In this study, Salmonella treatment resulted in the downregulation of β3-adrenoceptor expression and a decrease in the phosphorylation of the Protein Kinase-B (AKT)/Mammalian Target of Rapamycin (mTOR) pathway, as observed through immunoblotting in a dose-dependent manner. Notably, Salmonella treatment significantly reduced tumor cell migration, as demonstrated by wound healing and Transwell assays. Moreover, tumor-bearing mice that received Salmonella-pre-treated tumor cells exhibited improved survival rates compared to those injected with tumor cells without prior Salmonella treatment. The observed anti-metastatic effect in this study suggests that Salmonella treatment could hold promise as a potential therapeutic approach to combat tumor metastasis. Further research is warranted to explore its full therapeutic potential.

Salmonella inhibits tumor metastasis by downregulating epithelial cell adhesion molecules through the protein kinase-B/mammalian target of rapamycin signaling pathway

Epithelial cell adhesion molecules (EpCAM) are highly expressed in many carcinomas and regulate the epithelial-mesenchymal transition, which is required for tumor metastasis. Furthermore, EpCAM overexpression induces tumor cells to develop a stem cell-like phenotype and promotes tumor progression. Targeting EpCAM may be a promising approach for inhibiting tumor metastasis and progression. Salmonella treatment suppresses tumor growth and reduces metastatic nodules in tumor-bearing mice. Based on these results, we hypothesized that Salmonella-based treatments could inhibit the expression of metastasis-associated proteins. The dose-dependent Salmonella treatment significantly downregulated the levels of EpCAM and decreased the phosphorylation of protein kinase-B (AKT)/mTOR (mammalian target of rapamycin) pathway, as shown by immunoblotting. In addition, Salmonella treatment increased the levels of epithelial markers and decreased the levels of mesenchymal markers in a dose-dependent manner. Wound-healing and Transwell assays showed that Salmonella treatment significantly reduced tumor cell migration. The mice were intravenously injected with B16F10 and CT26 cells pre-incubated with or without Salmonella, and the survival of tumor-bearing mice in the Salmonella group increased, indicating an antimetastatic effect. Our findings demonstrate that Salmonella plays a role in inhibiting tumor metastasis by downregulating EpCAM via the AKT/mTOR signaling pathway and has great potential for cancer therapy.

Downregulation of AKT/mTOR signaling pathway for Salmonella-mediated autophagy in human anaplastic thyroid cancer

Thyroid cancer has been known as the most common endocrine malignancy. Although majority of thyroid cancer types respond well to conventional treatment including surgery and radioactive iodine therapy, about 10% of those with differentiated thyroid cancer will present distant metastasis and will have persistent or recurrent disease. Even more serious is a rare type of thyroid cancer called anaplastic thyroid cancer (ATC), which accounts for about 1%, has been demonstrated as the most lethal and aggressive form of human malignancy. Unfortunately, these tumors are also frequently resistant to traditional therapy. Previous study have shown that Salmonella inhibits tumor growth, in part, by inducing autophagy - a cellular process that is important in the innate and adaptive immunity in response to viral or bacterial infection. In our study, we intended to investigate whether Salmonella can inhibit tumor growth by inducing autophagy, specifically in thyroid cancer and elucidate the possible molecular mechanism. In order to determine the signaling pathway involved in tumor cell autophagy, we used Salmonella to treat ATC cells line ASH-3 and KMH-2 in vitro. The autophagic markers, particularly autophagy-related gene 6 (Beclin-1), microtubule-associated protein 1A/1B-light chain 3 (LC3) and p62, were observed to be differentially expressed after infection with Salmonella indicating an activated autophagy in ATC cells. In addition, the protein expression levels of phospho-protein kinase B (P-AKT), phospho-mammalian targets of rapamycin (P-mTOR), phospho-p70 ribosomal s6 kinase (P-p70S6K) in tumor cells were decreased after Salmonella infection. In vivo, we also found that substantial cell numbers of Salmonella targeted tumor tissue, and regulated anti-tumor mechanisms. Our findings showed that Salmonella activated autophagic signaling pathway and inhibited ATC tumor growth via downregulation of AKT/mTOR pathway.