Mycoplasma hyorhinisinfection in gastric carcinoma and its effects on the malignant phenotypes of gastric cancer cells

Hua Yang,Like Qu,Jian Wu,Caiyun Liu,Ling Chen,Wenbin Liu,Lin Meng,Huachong Ma,Chengchao Shou

doi:10.1186/1471-230x-10-132

Abstract

BackgroundMycoplasma hyorhinis infection has been postulated to play a role in the development of several types of cancer, but the direct evidence and mechanism remained to be determined.MethodsImmunohistochemistry assay and nested polymerase-chain reaction (PCR) were performed to examine the mycoplasma hyorhinis infection in gastric cancer tissues. Statistical analysis was used to check the association between mycoplasma infection and clinicopathologic parameters. Transwell chamber assay and metastasis assay were used to evaluate mycoplasma hyorhinis' effects on metastasis in vitro and in vivo. Mycoplasma hyorhinis-induced extracellular signal-regulated kinase (ERK) and epidermal growth factor receptor (EGFR) activation were investigated by Western blot.ResultsMycoplasma hyorhinis infection in gastric cancer tissues was revealed and statistical analysis indicated a significant association between mycoplasma infections and lymph node metastasis, Lauren's Classification, TNM stage, and age of the patients. Mycoplasma hyorhinis promoted tumor cell migration, invasion and metastasis in vitro and in vivo, which was possibly associated with the enhanced phosphorylation of EGFR and ERK1/2. The antibody against p37 protein of Mycoplasma hyorhinis could inhibit the migration of the infected cells.ConclusionsThe infection of mycoplasma hyorhinis may contribute to the development of gastric cancer and Mycoplasma hyorhinis-induced malignant phenotypes were possibly mediated by p37.

Highlights

Mycoplasma hyorhinis infection has been postulated to play a role in the development of several types of cancer, but the direct evidence and mechanism remained to be determined
We recently revealed that p37 promoted tumor cell motility, migration and invasion in vitro and enhanced tumor cell metastasis in C57BL/6 mice, which was mainly mediated by matrix metalloproteinase-2 (MMP-2) and the epidermal growth factor receptor (EGFR)/ MEK/extracellular signal-regulated kinase (ERK) pathway [6]
Statistical analysis of the relationship between polymerase-chain reaction (PCR) results and the data of clinical pathology and follow-up revealed that there was a significant association between mycoplasma infections, lymph node metastasis, Lauren’s Classification, TNM stage and age of the patients (P < 0.05) (Table 1)

Summary

Introduction

Mycoplasma hyorhinis infection has been postulated to play a role in the development of several types of cancer, but the direct evidence and mechanism remained to be determined. Our previous work demonstrated high infection rate of mycoplasma hyorhinis in gastric cancer tissues by immunohistochemistry (IHC) with PD4 monoclonal antibody against P37 protein of Mycoplastma hyorhinis. Exogenous p37 protein was found to alter gene expression profile, growth rate and morphology of prostate cancer cells [7]. All of these results suggest a possible link between mycoplasma infection and tumorigenesis, but the direct evidence remains elusive. The presence and the clinical significance of mycoplasma hyorhinis infection in gastric carcinoma tissues were analyzed with nested PCR and IHC assay. The biological effects of mycoplasma hyorhinis infection on gastric cancer cells and the possible molecular mechanisms were investigated

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Results

Discussion

Conclusion