BackgroundThe study aims to present the effect of PIK3CA E542K and E545K mutations on glucose metabolism and proliferation and identify their underlying mechanisms in cervical cancer.MethodsThe maximum standard uptake value (SUVmax) of tumors was detected by18F-FDG PET/CT scan. In vitro, glycolysis analysis, extracellular acidification rate analysis, and ATP production were used to evaluate the impact of PIK3CA E542K and E545K mutations on glucose metabolism. The expression level of key glycolytic enzymes was evaluated by western blotting and immunohistochemical staining in cervical cancer cells and tumor tissues, respectively. Immunofluorescence analysis was used to observe the nuclear translocation of β-catenin. The target gene of β-catenin was analyzed by using luciferase reporter system. The glucose metabolic ability of the xenograft models was assessed by SUVmax from microPET/CT scanning.ResultsCervical cancer patients with mutant PIK3CA (E542K and E545K) exhibited a higher SUVmax value than those with wild-type PIK3CA (P = 0.037), which was confirmed in xenograft models. In vitro, enhanced glucose metabolism and proliferation was observed in SiHa and MS751 cells with mutant PIK3CA. The mRNA and protein expression of key glycolytic enzymes was increased. AKT/GSK3β/β-catenin signaling was highly activated in SiHa and MS751 cells with mutant PIK3CA. Knocking down β-catenin expression decreased glucose uptake and lactate production. In addition, the nuclear accumulation of β-catenin was found in SiHa cells and tumors with mutant PIK3CA. Furthermore, β-catenin downregulated the expression of SIRT3 via suppressing the activity of the SIRT3 promotor, and the reduced glucose uptake and lactate production due to the downregulation of β-catenin can be reversed by the transfection of SIRT3 siRNA in SiHa cells with mutant PIK3CA. The negative correlation between β-catenin and SIRT3 was further confirmed in cervical cancer tissues.ConclusionsThese findings provide evidence that the PI3K E542K and E545K/β-catenin/SIRT3 signaling axis regulates glucose metabolism and proliferation in cervical cancers with PIK3CA mutations, suggesting therapeutic targets in the treatment of cervical cancers.Trial registrationFUSCC 050432–4-1212B. Registered 24 December 2012 (retrospectively registered).Electronic supplementary materialThe online version of this article (10.1186/s13045-018-0674-5) contains supplementary material, which is available to authorized users.

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ObjectiveThe predictive and prognostic role of KRAS mutations in cervical cancer remains inconclusive. The aim of this study was to explore the clinicopathological and prognostic relevance of KRAS mutations in invasive cervical cancers (ICC).MethodsReverse transcription polymerase chain reaction (PCR) and Sanger sequencing were employed to detect KRAS mutations in 876 ICC patients. Quantitative real-time PCR was used to detect human papillomavirus (HPV) 16 and HPV 18.ResultsNon-synonymous mutations of KRAS were identified in 30 (3.4%) patients. These mutations were more common in non-squamous cell carcinoma than in squamous cell carcinoma (SCC) (8.2% vs. 2.2%, respectively, p<0.001) and were associated with HPV 18 infection (p=0.003). The prevalence of mutations was highest (18.2%) in the uncommon histological subtypes followed by adenocarcinoma (AC, 7.3%) and adenosquamous carcinoma (ASC, 5.8%). During the median follow-up of 55 months, compared to patients with wild-type KRAS, a greater percentage of patients with mutant KRAS relapsed (20.0% vs. 42.9%, respectively, p=0.007). The 3-year relapse-free survival was poorer in patients with mutant KRAS than in patients without KRAS mutations (57.1% vs. 81.9%, respectively, p=0.001). Furthermore, the multivariate analysis showed that the presence of a KRAS mutation was an independent predictor for disease recurrence (hazard ratio [HR]=2.064; 95% confidence interval [CI]=1.125–3.787; p=0.019).ConclusionKRAS mutations were predominant in non-SCCs of the cervix and were associated with HPV 18 infection. A combination of KRAS mutation detection and HPV genotyping would be useful in identifying patient with poor prognosis for further interventions.