Antiviral activity of Bifidobacterium adolescentisSPM1005-A on human papillomavirus type 16

Min-Kyeong Cha,Nam-Joo Ha,Do-Kyung Lee,Si-Won Lee,Jeong-Hyun Kwon,Hyang-Mi An,Seon-Hee Shin,Kyung-Jae Kim

doi:10.1186/1741-7015-10-72

Min-Kyeong Cha, Nam-Joo Ha + Show 6 more

Open Access

https://doi.org/10.1186/1741-7015-10-72

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Abstract

BackgroundProbiotic lactic acid bacteria (LAB) support a functional and balanced immune system, and contribute to immune modulatory effects in combatting microbial pathogens, including viruses. Most cervical cancers are associated with anogenital region infection with high-risk (HR) human papillomavirus (HPV). In this study, we analyzed the antiviral activity of Bifidobacterium adolescentis SPM1005-A in the SiHa cervical cancer cell line expressing HPV type 16.MethodsWe assessed the cellular toxicity of B. adolescentis SPM1005-A in SiHa cells by the Trypan blue dye exclusion assay. Cells (3.6 × 105) in culture plates with or without B. adolescentis SPM1005-A in the same type of medium, were incubated with HPV type 16 at a concentration of 5.1 × 107 cfu/ml. For antiviral analysis, we performed quantitative real-time PCR (qRT-PCR) for E6 and E7 oncogene expressions and observed protein levels by immunoblotting.ResultsThe qRT-PCR results showed that E6 and E7 mRNA levels decreased simultaneously. Western blot analysis revealed that the E6 protein expression slightly decreased after 24 and 48 h, but the level of E7 protein expression appear unaffected compared with that in the control. Decreased HPV16 E6 and E7 mRNA transcript and protein levels were not associated with cell morphology or significant cytotoxic effects.ConclusionsThis study showed that B. adolescentis SPM1005-A had antiviral activity through suppression E6 and E7 oncogene expression. The results suggest that B. adolescentis SPM1005-A could be potential applications of HPV-associated cervical cancer prevention.

Highlights

Probiotic lactic acid bacteria (LAB) support a functional and balanced immune system, and contribute to immune modulatory effects in combatting microbial pathogens, including viruses
As growth of human papillomavirus (HPV)-transformed cervical cancer cells is dependent on sustained viral oncogene E6 and E7 expression, we investigated the inhibitory effects of B. adolescentis SPM1005-A on the cervical carcinoma cell line, SiHa, with quantitative real-time PCR, which is an excellent method for quantitation of viral DNA [20,21]
Compared to control phosphate-buffered saline (PBS)-treated cells, cells exposed to B. adolescentis SPM1005-A for 72 h slowly shrank in appearance, but there was no observed difference in 24-h to 72-h treated cells

Summary

Introduction

Probiotic lactic acid bacteria (LAB) support a functional and balanced immune system, and contribute to immune modulatory effects in combatting microbial pathogens, including viruses. Most cervical cancers are associated with anogenital region infection with high-risk (HR) human papillomavirus (HPV). We analyzed the antiviral activity of Bifidobacterium adolescentis SPM1005-A in the SiHa cervical cancer cell line expressing HPV type 16. Most cervical cancers are associated with the anogenital region or mucosa cell infection with human papillomavirus (HPV) [2]. The malignant phenotype of HR types depends on the expression of two viral genes E6 and E7, which bind to p53 and retinoblastoma protein (pRb) and neutralize their function, respectively [5]. The most important function of E6 protein is binding of the tumor suppressor p53, which leads to it degradation through an ubiquitin proteolytic pathway. The studies for inhibitors of the oncogenic proteins E6 and E7 of HPV type 16 are constantly in progress

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