Metformin inhibits proliferation of human keratinocytes through a mechanism associated with activation of the MAPK signaling pathway

Abstract

In the present study, the effects of metformin on the proliferation of human immortalized keratinocytes (HaCaTs) and the underlying mechanisms were investigated. HaCaT cells in the logarithmic growth phase were treated with 50 mM metformin for 24, 48 and 72 h. Cell morphology after 24 h of treatment was observed under a microscope. Cell proliferation was detected using a colorimetric cell proliferation and cytotoxicity assay kit. Western blot analyses were performed to detect the protein phosphorylation levels of adenosine monophosphate-activated protein kinase (AMPK) and extracellular signal-related kinase 1/2 (ERK1/2). Metformin treatment resulted in morphological changes of the HaCaT cells. The survival rates of HaCaT cells treated with metformin were 36.18, 12.70 and 10.12% at 24, 48 and 72 h, respectively. As the treatment time extended, the survival rates of HaCaT cells decreased. Western blot analysis results showed that the mean level of phosphorylated (p)-AMPK in the HaCaT cells without metformin treatment was 2.856±0.323. However, the mean p-AMPK level following metformin treatment for 24 h increased to 5.198±0.625, indicating a significant difference between these two groups (P<0.05). The mean absorbance ratio of p-ERK1/2 was 7.550±1.087 for the untreated cells, but the levels in cells following metformin treatment for 24 h increased to 10.430±1.217, indicating a significant difference between the two groups (P<0.05). In conclusion, metformin treatment upregulated the levels of p-AMPK and p-ERK1/2 in HaCaT cells, and significantly inhibited HaCaT cell proliferation in vitro by a mechanism associated with activation of the mitogen-activated protein kinase signaling pathway.

Metformin inhibits proliferation and proinflammatory cytokines of human keratinocytesin vitrovia mTOR-signaling pathway

“…To study the mechanism of metformin in treating epidermal hyperplastic diseases such as psoriasis, we previously reported that metformin inhibited HaCaT cells proliferation in vitro by upregulating AMPK and Erk pathway (Li et al, 2014). In the current study, we found that metformin not only inhibited cell proliferation but also induced HaCaT cell apoptosis.…”

“…Inhibition of the mTOR pathway can inhibit multiple proinflammatory cytokines including IL-6, TNF-a, and VEGF (Kirsch et al, 2012), which play important roles in the pathogenesis of psoriasis. Our previous study showed that metformin could inhibit the proliferation of human keratinocytes in association with the activation of the AMPK signaling pathway (Li et al, 2014). However, whether metformin suppresses human keratinocyte proliferation by specifically targeting the mTOR signaling pathway has not been studied.…”

Mechanism of action and effect of immune-modulating agents in the treatment of psoriasis

“…Based on the extent of involvement and effect on the quality of life, psoriasis may be mild to moderate in severity. This approach, in turn, forms the basis of treatment in a majority of patients [2].…”

Metformin-Derived Growth Inhibition in Renal Cell Carcinoma Depends on miR-21-Mediated <b><i>PTEN</i></b> Expression

“…MF is an anti-diabetic drug which - besides improving glycaemic control - alters multiple pathways in benign and transformed cells leading to the inhibition of proliferation, cell cycle arrest and apoptosis [1,2,3]. …”