AKT Inhibitors Promote Cell Death in Cervical Cancer through Disruption of mTOR Signaling and Glucose Uptake

Abstract

BackgroundPI3K/AKT pathway alterations are associated with incomplete response to chemoradiation in human cervical cancer. This study was performed to test for mutations in the PI3K pathway and to evaluate the effects of AKT inhibitors on glucose uptake and cell viability.Experimental DesignMutational analysis of DNA from 140 pretreatment tumor biopsies and 8 human cervical cancer cell lines was performed. C33A cells (PIK3CAR88Q and PTENR233*) were treated with increasing concentrations of two allosteric AKT inhibitors (SC-66 and MK-2206) with or without the glucose analogue 2-deoxyglucose (2-DG). Cell viability and activation status of the AKT/mTOR pathway were determined in response to the treatment. Glucose uptake was evaluated by incubation with 18F-fluorodeoxyglucose (FDG). Cell migration was assessed by scratch assay.ResultsActivating PIK3CA (E545K, E542K) and inactivating PTEN (R233*) mutations were identified in human cervical cancer. SC-66 effectively inhibited AKT, mTOR and mTOR substrates in C33A cells. SC-66 inhibited glucose uptake via reduced delivery of Glut1 and Glut4 to the cell membrane. SC-66 (1 µg/ml-56%) and MK-2206 (30 µM-49%) treatment decreased cell viability through a non-apoptotic mechanism. Decreases in cell viability were enhanced when AKT inhibitors were combined with 2-DG. The scratch assay showed a substantial reduction in cell migration upon SC-66 treatment.ConclusionsThe mutational spectrum of the PI3K/AKT pathway in cervical cancer is complex. AKT inhibitors effectively block mTORC1/2, decrease glucose uptake, glycolysis, and decrease cell viability in vitro. These results suggest that AKT inhibitors may improve response to chemoradiation in cervical cancer.

Acute stimulation of glucose influx upon mitoenergetic dysfunction requires LKB1, AMPK, Sirt2 and mTOR–RAPTOR

“…This interaction between Sirt2 and Akt is required to allow optimal Akt activation. In this sense, previous evidence has revealed that Akt inhibitors effectively block the mammalian target of rapamycin complex 1 (mTORC1; containing mTOR and RAPTOR) and decrease glucose uptake, glycolytic rate and cell viability (Rashmi et al, 2014). In agreement with our above results, it has been concluded previously that mTOR-RAPTOR promotes Glut1 activity but does not regulate Glut1 surface localization (Wieman et al , 2007).…”

“…In order to assess the potential involvement of Akt in the piericidin-A-and antimycin-A-induced increase in glucose uptake, we tested the pan-Akt inhibitor SC-66 (Jo et al, 2011). Pretreatment with SC-66 (10 μg/ml, 1 h) (Rashmi et al, 2014) did not reduce the stimulation of glucose uptake in inhibitor-treated cells (data not shown). Assuming that the effect of SC-66 is Akt specific, this result argues against involvement of Akt in the stimulation of glucose uptake.…”

Effects of AKT inhibition on HGF-mediated erlotinib resistance in non-small cell lung cancer cell lines

“…Prior studies have shown anticancer activity of MK-2206 across multiple tumor types as well as synergy with established chemotherapeutic agents in NSCLC (Agarwal et al 2014; Almhanna et al 2013; Hirai et al 2010; Konopleva et al 2014; Rashmi et al 2014). Additional work has indicated synergy and enhanced cytotoxicity when MK-2206 is combined with EGFR inhibitors including erlotinib, gefitinib, and cetuximab in the context of a limited number of NSCLC, breast, and glioma cell lines (Cheng et al 2012; Hirai et al 2010; Iida et al 2013).…”

PTEN expression in patients with carcinoma of the cervix and its association with p53, Ki-67 and CD31

“…PTEN mutations were frequently found in cancers arising from the endometrium 29,30 , brain 31 and prostate 32 . Rashmi et al 33 found results with activating PIK3CA (E545K, E542K) and inactivating PTEN (R233) mutations were identified in human cervical cancer. An analysis of PTEN gene in squamous cell carcinomas from other sites also found that PTEN is not frequently mutated in the lung 34 , cervix 14 , skin 35 , head and neck 36 or esophagus 37 .…”