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Effects of Metformin on the virus/host cell crosstalk in human papillomavirus‐positive cancer cells
Author(s) -
HoppeSeyler Karin,
Herrmann Anja L.,
Däschle Antonia,
Kuhn Bianca J.,
Strobel Tobias D.,
Lohrey Claudia,
Bulkescher Julia,
Krijgsveld Jeroen,
HoppeSeyler Felix
Publication year - 2021
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.33594
Subject(s) - metformin , psychological repression , cancer research , pi3k/akt/mtor pathway , cancer cell , cancer , downregulation and upregulation , senescence , biology , oncogene , immunology , medicine , cell cycle , signal transduction , microbiology and biotechnology , endocrinology , gene expression , gene , genetics , diabetes mellitus
Abstract Oncogenic types of human papillomaviruses (HPVs) are major human carcinogens. The viral E6/E7 oncogenes maintain the malignant growth of HPV‐positive cancer cells. Targeted E6/E7 inhibition results in efficient induction of cellular senescence, which could be exploited for therapeutic purposes. Here we show that viral E6/E7 expression is strongly downregulated by Metformin in HPV‐positive cervical cancer and head and neck cancer cells, both at the transcript and protein level. Metformin‐induced E6/E7 repression is glucose and PI3K‐dependent but—other than E6/E7 repression under hypoxia—AKT‐independent. Proteome analyses reveal that Metformin‐induced HPV oncogene repression is linked to the downregulation of cellular factors associated with E6/E7 expression in HPV‐positive cancer biopsies. Notably, despite efficient E6/E7 repression, Metformin induces only a reversible proliferative stop in HPV‐positive cancer cells and enables them to evade senescence. Metformin also efficiently blocks senescence induction in HPV‐positive cancer cells in response to targeted E6/E7 inhibition by RNA interference. Moreover, Metformin treatment enables HPV‐positive cancer cells to escape from chemotherapy‐induced senescence. These findings uncover profound effects of Metformin on the virus/host cell interactions and the phenotype of HPV‐positive cancer cells with implications for therapy‐induced senescence, for attempts to repurpose Metformin as an anticancer agent and for the development of E6/E7‐inhibitory therapeutic strategies.