title: Anti-tumor effects of metformin on head and neck carcinoma cell lines: A systematic review.
abstract: Metformin is commonly used for treating type 2 diabetes, and may also reduce cancer risk. Previous studies have demonstrated the association between metformin use and a decreased risk of head and neck cancer. Therefore, the aim of the present systematic review was to summarize the available literature on thein vitroanti-tumor effects of metformin on head and neck squamous cell carcinoma (HNSCC). Research studies were obtained from Cochrane Library, Embase, LILACS, MEDLINE and PubMed databases, without time or language restrictions. Onlyin vitrostudies analyzing the effects of metformin on HNSCC cell lines were included. The authors methodically appraised all the selected studies according to the Grading of Recommendations Assessment, Development and Evaluation method to make a judgment of the evidence quality. Of the 388 identified reports, 11 studies met the inclusion criteria and were used for qualitative analysis. These studies demonstrated that metformin is important in inhibiting cell proliferation, inducing G0/G1 cell cycle arrest and apoptosis, and in regulating proteins involved in carcinogenesis pathways, which corroborates its potentialin vitroanti-tumor effects. The present systematic review highlights the biological mechanisms of metformin used alone or together with traditional therapies for cancer. Though very limited, currently available preclinical evidence shows that metformin exerts a potential effect on head and neck carcinoma.
authors.affiliation: Laboratory of Oral Histopathology, School of Health Sciences, University of Brasília, Brasília 70843-080, Brazil.
authors.forename: Daniela Fortunato
authors.initials: DF
authors.lastname: Rêgo
authors.affiliation: Laboratory of Oral Histopathology, School of Health Sciences, University of Brasília, Brasília 70843-080, Brazil.
authors.forename: Silvia Taveira
authors.initials: ST
authors.lastname: Elias
authors.affiliation: Laboratory of Molecular Pharmacology, Department of Pharmaceutical Sciences, School of Health Sciences, University of Brasília, Brasília 70919-970, Brazil.
authors.forename: AngéLica Amorim
authors.initials: AA
authors.lastname: Amato
authors.affiliation: Department of Dentistry, Federal University of Santa Catarina, Florianópolis 88036-800, Brazil; Department of Dentistry, University of Alberta, Edmonton T6G 1C9, Canada.
authors.forename: Graziela De Luca
authors.initials: GL
authors.lastname: Canto
authors.affiliation: Laboratory of Oral Histopathology, School of Health Sciences, University of Brasília, Brasília 70843-080, Brazil.
authors.forename: Eliete Neves Silva
authors.initials: EN
authors.lastname: Guerra
keywords: evidence-based medicine; head and neck; metformin; squamous cell carcinoma; systematic review