Metformin Potentiates the Anticancer Effect of Everolimus on Cervical Cancer In Vitro and In Vivo

Abstract

Cervical cancer is globally the fourth most common cancer in women. Metformin is a widely used drug for the treatment of type II diabetes and has been shown to possess important anticancer properties in cervical cancer. Everolimus is an mTOR inhibitor and is widely used to treat NETs, RCC, TSC, and breast cancers. The present study investigated the anticancer effects of metformin and everolimus in cervical cancer, when used alone or in combination. CaSki and C33A human cervical cancer cells were treated with different concentrations of everolimus alone or in combination with metformin. Cell viability was assessed using a CCK-8 assay. Cell apoptosis, cell-cycle, and mtROS analyses were conducted using flow cytometry. Target protein levels were analyzed by Western blotting. Related mechanisms were confirmed using appropriate inhibitors (z-VAD-fmk and BIRB796). The in vitro results were further confirmed in a xenograft tumor study. Both metformin and everolimus, when used alone, were moderately effective in inhibiting cell proliferation and inducing cell apoptosis of CaSki and C33A cells. When used in combination, these two drugs synergistically inhibited the growth of human cervical cancer cells and xenografts in nude mice, promoted sub-G1- and G0/G1-phase cell-cycle arrest, and enhanced mtROS production. The protein expressions of PI3K (p110α) and p-AKT were significantly downregulated, while P27, P21, p-p38, p-ERK, and p-JNK were upregulated following combined treatment. These results revealed that metformin potentiates the anticancer effect of everolimus on cervical cancer, and combination treatment with metformin and everolimus provides a novel therapeutic strategy for patients with cervical cancer.

Activation of AMPK inhibits cervical cancer growth by hyperacetylation of H3K9 through PCAF

“…In particular, some studies involving metformin in non-diabetic cancer patients have yielded promising results [34,35]. Although recent studies by our group and others have found that metformin has significant anti-cervical cancer activity, the mechanisms behind this effect remain elusive [36][37][38][39]. To investigate this, we first used the CCK-8 assay to identify whether metformin induced anti-proliferative activities in different cervical cancer cells.…”

Everolimus (RAD001) combined with programmed death-1 (PD-1) blockade enhances radiosensitivity of cervical cancer and programmed death-ligand 1 (PD-L1) expression by blocking the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR)/S6 kinase 1 (S6K1) pathway

“…RT is an accepted treatment for CC, while reoccurrence of CC has emerged after RT owing to low radiosensitivity [ 53 , 54 ]. Additionally, mTOR inhibitor RAD001 possesses an anticancer effect on CC [ 55 ]. PD-L1 expression has been documented in most cervical squamous cell cancers, indicating the potential effectiveness of anti-PD-1 therapies for CC [ 56 ].…”

Metformin suppresses foam cell formation, inflammation and ferroptosis via the AMPK/ERK signaling pathway in ox‑LDL‑induced THP‑1 monocytes

“…Metformin is a therapeutic drug used for type 2 diabetes (15). Studies have shown that metformin can reduce the risk of breast cancer (16), cervical cancer (17,18), prostate cancer (19), gastric cancer (20) and other types of cancer. Metformin promotes an anti-inflammatory effect on macrophages by suppressing fatty acid synthase-dependent palmitoylation of AKT (21).…”