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FOXE1 Represses Cell Proliferation and Warburg Effect by Inhibiting HK2 in Colorectal Cancer

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FOXE1 Represses Cell Proliferation and Warburg Effect by Inhibiting HK2 in Colorectal Cancer

Weixing Dai et al. Cell Commun Signal.

Abstract

Background: Low expression of FOXE1, a member of Forkhead box (FOX) transcription factor family that plays vital roles in cancers, contributes to poor prognosis of colorectal cancer (CRC) patients. However, the underlying mechanism remains unclear.

Materials and methods: The effects of FOXE1 on the growth of colon cancer cells and the expression of glycolytic enzymes were investigated in vitro and in vivo. Molecular biological experiments were used to reveal the underlying mechanisms of altered aerobic glycolysis. CRC tissue specimens were used to determine the clinical association of ectopic metabolism caused by dysregulated FOXE1.

Results: FOXE1 is highly expressed in normal colon tissues compared with cancer tissues and low expression of FOXE1 is significantly associated with poor prognosis of CRC patients. Silencing FOXE1 in CRC cell lines dramatically enhanced cell proliferation and colony formation and promoted glucose consumption and lactate production, while enforced expression of FOXE1 manifested the opposite effects. Mechanistically, FOXE1 bound directly to the promoter region of HK2 and negatively regulated its transcription. Furthermore, the expression of FOXE1 in CRC tissues was negatively correlated with that of HK2.

Conclusion: FOXE1 functions as a critical tumor suppressor in regulating tumor growth and glycolysis via suppressing HK2 in CRC.

Keywords: Cell proliferation; FOXE1; Glycolysis; HK2.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Low FOXE1 expression predicted poor survival for CRC. a Representative images showing low FOXE1 expression in CRC tissues (right panel) compared with adjacent normal tissues (left panel). b FOXE1 expression is significantly higher in paired normal tissues than in CRC tissue specimens (P < 0.001). c and d FOXE1 expression in one normal colonic epithelial cell NCM460 and six CRC cell lines determined using qRT-PCR analysis (c) and western blotting (d). e and f Kaplan–Meier analysis of the correlation of FOXE1 expression with OS (e) and DFS (f)
Fig. 2
Fig. 2
Enforced FOXE1 expression inhibited cell growth in vitro and in vivo. a Validation of over-expression FOXE1 in HCT116 and LoVo cells using western blotting and qRT-PCR. b, c and d The impact of FOXE1 expression on cell proliferation (b), colony formation (c) and cell cycle (d). e, f and g HCT116-Vector and HCT116-FOXE1 were subcutaneously injected into the right and left forelimb of five nude mice (5 × 106 cells each xenograft). Gross xenografts (e), tumor growth curves (f) and tumors weights (g) are shown. *P < 0.05
Fig. 3
Fig. 3
Silence of FOXE1 expression promotes cell growth in vitro and in vivo. a Validation of attenuated-expression FOXE1 in SW480 and HT29 using western blotting and qRT-PCR. b, c and d The impact of silenced FOXE1 expression on cell proliferation (b), colony formation (c) and cell cycle (d). e, f and g. SW480-NC and SW480-FOXE1-KD#1 were subcutaneously injected into the right and left forelimb of five nude mice (5 × 106 cells each xenograft). Gross xenografts (e), tumor growth curves (f) and tumors weights (g) are shown. *P < 0.05
Fig. 4
Fig. 4
FOXE1 repressed glycolysis in CRC cells. a, b Attenuated FOXE1 expression promotes glucose uptake (a) and lactate proguction (b) in SW480 and HT29 cells. c and d Enforced expression of FOXE1 inhibits glucose uptake (c) and lactate proguction (d) in HCT116 and LoVo cells. e and f ECAR value increased significantly in FOXE1 silenced SW480 cell (e) but decreased in FOXE1 over-expressed HCT116 cell (f). g and h OCR value decreased significantly in FOXE1 silenced SW480 cell (g) but increased in FOXE1 over-expressed HCT116 cell (h). *P < 0.05
Fig. 5
Fig. 5
FOXE1 repressed glycolysis in vivo and FOXE1 expression is negatively correlated with18F-FDG PET/CT SUVmax value in CRC patients. a and b Representative photographs of 18F-FDG PET/CT scans of mice injected with HCT116-FOXE1-KD#1 and control(NC). The SUVmax was significantly higher in the HCT116-FOXE1-KD#1 group than in the control group (P < 0.05). c and d Representative photographs of 18F-FDG PET/CT scans and the corresponding FOXE1 IHC stains of CRC specimens. Patients with low expression of FOXE1 (red points) showed significantly higher SUVmax than patients high FOXE1 expression (blue points)
Fig. 6
Fig. 6
FOXE1 suppressed glycolysis via inhibiting HK2 expression. a Histograms showing the changes in mRNA expression for critical enzymes involved in glycolysis. b Forced FOXE1 expression inhibits the expression of the glycolytic enzyme HK2. c Attenuated FOXE1 expression promotes the expression of the HK2. d, e IHC stains of CRC specimens from patients showing that FOXE1 expression was negatively associated with HK2 expression. *P < 0.05
Fig. 7
Fig. 7
FOXE1 is a transcription factor of HK2. a Luciferase activity of the pGL3-HK2-Luc in HCT116 and LoVo cells being transfected with FOXE1 plasmid. b The truncated HK2 promoter regions were cloned into the pGL3 plasmid. c Enhanced FOXE1 expression strongly enhanced the promoter activity of the P1 but not the P2, P3 and P4 regions. d ChIP assays performed in HCT116 and LoVo cells. Specific anti-Flag antibody for ectopically expressed Flag-FOXE1, but not isotype IgG, captured the fragment that possibly containing the FOXE1 response element in the HK2 promoter region. *P < 0.05
Fig. 8
Fig. 8
Silence of HK2 inhibited cell growth and glycolysis in CRC cells. a Validation of attenuated-expression HK2 in HCT116 and LoVo using western blotting and qRT-PCR. b, c and d. The impact of HK2 expression on cell proliferation (b), colony formation (c) and cell cycle (d). e and f. Silence of HK2 inhibited glucose uptake and lactate production. g, h and i. HCT116-NC and HCT116-FOXE1-KD#1 were subcutaneously injected into the right and left forelimb of five nude mice (5 × 106 cells each xenograft). Gross xenografts (g), tumor growth curves (h) and tumors weights (i) are shown. *P < 0.05

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References

    1. Brenner H, Kloor M, Pox CP. Colorectal cancer. Lancet. 2014;383(9927):1490–1502. doi: 10.1016/S0140-6736(13)61649-9. - DOI - PubMed
    1. Edge SB, Byrd DR, Compton CC, Fritz AG, Greene FL, Trotti A., III . AJCC Cancer staging manual. 7. New York: Springer-Verlag; 2010.
    1. Sargent DJ, Wieand HS, Haller DG, Gray R, Benedetti JK, Buyse M, et al. Disease-free survival versus overall survival as a primary end point for adjuvant colon cancer studies: individual patient data from 20,898 patients on 18 randomized trials. J Clin Oncol. 2005;23(34):8664–8670. doi: 10.1200/JCO.2005.01.6071. - DOI - PubMed
    1. Evan GI, Vousden KH. Proliferation, cell cycle and apoptosis in cancer. Nature. 2001;411(6835):342–348. doi: 10.1038/35077213. - DOI - PubMed
    1. Cantor JR, Sabatini DM. Cancer cell metabolism: one hallmark, many faces. Cancer Discov. 2012;2(10):881–898. doi: 10.1158/2159-8290.CD-12-0345. - DOI - PMC - PubMed

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