Digestive Diseases and Sciences

, Volume 59, Issue 3, pp 598–606 | Cite as

PAX6, a Novel Target of microRNA-7, Promotes Cellular Proliferation and Invasion in Human Colorectal Cancer Cells

  • Yanwen Li
  • Yuehui Li
  • Yanhong Liu
  • Pingli Xie
  • Feng Li
  • Guancheng LiEmail author
Original Article



Paired box 6 (PAX6), a highly conserved transcriptional factor, has been implicated in tumorigenesis.


We aimed to explore the roles and molecular mechanisms of PAX6 and microRNA (miR-7) in colorectal cancer cells.


Tissue microarray immunohistochemistry and Western blot were applied to examine the PAX6 expression. Real-time RT-PCR and Western blot were performed to determine the expression of miR-7 and PAX6. Luciferase reporter assay was used to determine whether PAX6 was a target of miR-7. Effects of miR-7 and PAX6 on colorectal cell proliferation, cell cycle progression, colony formation and invasion were then investigated. Western blot was used to determine the activities of the ERK and PI3K signal pathways, as well as the protein expression of MMP2 and MMP9.


The protein levels of PAX6 were gradually increased, while the expression of miR-7 was gradually reduced with malignancy of colorectal cancer. PAX6 was further identified as a target of miR-7, and its protein expression was negatively regulated by miR-7 in human colorectal cancer cells. Overexpression of PAX6 in Caco-2 and SW480 cells enhanced cellular proliferation, cell cycle progression, colony formation, and invasion, while miR-7 upregulation repressed these biological processes. Furthermore, the activities of ERK and PI3K signal pathways, as well as the protein levels of MMP2 and MMP9, were upregulated in PAX6-overexpressed Caco-2 and SW480 cells but deregulated in miR-7-overexpressed Caco-2 and SW480 cells.


Our study suggests that as a novel target of miR-7, PAX6 may serve as a promising therapeutic target for colorectal cancer.


Colorectal cancer Paired box 6 (PAX6) MicroRNA-7 Proliferation Invasion 


Conflict of interest



  1. 1.
    Walther C, Guenet JL, Simon D, et al. Pax: a murine multigene family of paired box-containing genes. Genomics. 1991;11:424–434.PubMedCrossRefGoogle Scholar
  2. 2.
    Georgala PA, Carr CB, Price DJ. The role of Pax6 in forebrain development. Dev Neurobiol. 2011;71:690–709.PubMedCrossRefGoogle Scholar
  3. 3.
    Eriksson BJ, Samadi L, Schmid A. The expression pattern of the genes engrailed, pax6, otd and six3 with special respect to head and eye development in Euperipatoides kanangrensis Reid 1996 (Onychophora: Peripatopsidae). Dev Genes Evol. 2013;223:237–246.PubMedCrossRefGoogle Scholar
  4. 4.
    Hart AW, Mella S, Mendrychowski J, van Heyningen V, Kleinjan DA. The developmental regulator Pax6 is essential for maintenance of islet cell function in the adult mouse pancreas. PLoS One. 2013;8:e54173.PubMedCentralPubMedCrossRefGoogle Scholar
  5. 5.
    Elso C, Lu X, Weisner PA, et al. A reciprocal translocation dissects roles of Pax6 alternative promoters and upstream regulatory elements in the development of pancreas, brain, and eye. Genesis. 2013;51:630–646.PubMedGoogle Scholar
  6. 6.
    Liu RZ, Monckton EA, Godbout R. Regulation of the FABP7 gene by PAX6 in malignant glioma cells. Biochem Biophys Res Commun. 2012;422:482–487.PubMedCrossRefGoogle Scholar
  7. 7.
    Wang J, Wang X, Wu G, Hou D, Hu Q. MiR-365b-3p, down-regulated in retinoblastoma, regulates cell cycle progression and apoptosis of human retinoblastoma cells by targeting Pax6. FEBS Lett. 2013;587:1779–1786.PubMedCrossRefGoogle Scholar
  8. 8.
    Zong X, Yang H, Yu Y, et al. Possible role of Pax-6 in promoting breast cancer cell proliferation and tumorigenesis. BMB Rep. 2011;44:595–600.PubMedCrossRefGoogle Scholar
  9. 9.
    Shyr CR, Tsai MY, Yeh S, et al. Tumor suppressor PAX6 functions as androgen receptor co-repressor to inhibit prostate cancer growth. Prostate. 2010;70:190–199.PubMedCentralPubMedGoogle Scholar
  10. 10.
    Hellwinkel OJ, Kedia M, Isbarn H, Budaus L, Friedrich MG. Methylation of the TPEF- and PAX6-promoters is increased in early bladder cancer and in normal mucosa adjacent to pTa tumours. BJU Int. 2008;101:753–757.PubMedCrossRefGoogle Scholar
  11. 11.
    Salem CE, Markl ID, Bender CM, Gonzales FA, Jones PA, Liang G. PAX6 methylation and ectopic expression in human tumor cells. Int J Cancer. 2000;87:179–185.PubMedCrossRefGoogle Scholar
  12. 12.
    Ambros V. The functions of animal microRNAs. Nature. 2004;431:350–355.PubMedCrossRefGoogle Scholar
  13. 13.
    Shen J, Stass SA, Jiang F. MicroRNAs as potential biomarkers in human solid tumors. Cancer Lett. 2013;329:125–136.PubMedCrossRefGoogle Scholar
  14. 14.
    Nana-Sinkam SP, Croce CM. Clinical applications for microRNAs in cancer. Clin Pharmacol Ther. 2013;93:98–104.PubMedCrossRefGoogle Scholar
  15. 15.
    Zhang N, Li X, Wu CW et al. microRNA-7 is a novel inhibitor of YY1 contributing to colorectal tumorigenesis. Oncogene. 2013;32:5078–5088.Google Scholar
  16. 16.
    Boncheva V, Bonney SA, Brooks SE, et al. New targets for the immunotherapy of colon cancer-does reactive disease hold the answer? Cancer Gene Ther. 2013;20:157–168.PubMedCrossRefGoogle Scholar
  17. 17.
    Simpson TI, Price DJ. Pax6; a pleiotropic player in development. Bioessays. 2002;24:1041–1051.PubMedCrossRefGoogle Scholar
  18. 18.
    Li L, Li B, Zhang H, et al. Lentiviral vector-mediated PAX6 overexpression promotes growth and inhibits apoptosis of human retinoblastoma cells. Invest Ophthalmol Vis Sci. 2011;52:8393–8400.PubMedCrossRefGoogle Scholar
  19. 19.
    Wang S, J Xiang, Li Z, et al. A plasma microRNA panel for early detection of colorectal cancer. Int J Cancer. 2013.doi: 10.1002/ijc.28136
  20. 20.
    Kredo-Russo S, Mandelbaum AD, Ness A, et al. Pancreas-enriched miRNA refines endocrine cell differentiation. Development. 2012;139:3021–3031.PubMedCrossRefGoogle Scholar
  21. 21.
    Chetram MA, Hinton CV. PTEN regulation of ERK1/2 signaling in cancer. J Recept Signal Transduct Res. 2012;32:190–195.PubMedCentralPubMedCrossRefGoogle Scholar
  22. 22.
    Artacho-Cordon F, Rios-Arrabal S, Lara PC, Artacho-Cordon A, Calvente I, Nunez MI. Matrix metalloproteinases: potential therapy to prevent the development of second malignancies after breast radiotherapy. Surg Oncol. 2012;21:e143–e151.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Yanwen Li
    • 1
    • 2
  • Yuehui Li
    • 1
  • Yanhong Liu
    • 1
  • Pingli Xie
    • 1
  • Feng Li
    • 1
  • Guancheng Li
    • 1
    Email author
  1. 1.Tumor Immunobiology Laboratory of Cancer Research Institute, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Ministry of HealthCentral South UniversityChangshaChina
  2. 2.Clinical LaboratoryThe First Affiliated Hospital of Nanhua UniversityHengyangChina

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