Cancer driver candidate genes AVL9, DENND5A and NUPL1 contribute to MDCK cystogenesis

Yaping Li1,*, Jianing Xu1,4,*, Huan Xiong1, Zhongyao Ma1, Zhenghe Wang2, Edward T. Kipreos3, Stephen Dalton1 and Shaying Zhao1

1 Department of Biochemistry and Molecular Biology, Institute of Bioinformatics, University of Georgia, Athens

2 Department of Genetics & Genome Sciences and Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio

3 Department of Cellular Biology, University of Georgia, Athens

4 Current Address: Human Oncology & Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York

* These authors contributed equally to this work


Francis Crick, email:

Keywords: AVL9; DENND5A; NUPL1; MDCK; Cytogenesis; Apicobasal Polarity

Received: November 10, 2014 Accepted: December 14, 2014 Published: December 15, 2014


AVL9, DENND5A and NUPL1 are among the cancer driver candidate genes previously identified via dog-human comparison, and may function in epithelial cell polarity as indicated by bioinformatics analysis. To better understand their cellular functions and roles in cancer, we knocked down each gene in MDCKII cells through shRNA and performed three-dimensional culture. Compared to the control, the knockdown clones developed significantly more abnormal cysts, e.g., cysts with the lumen harboring dead and/or live cells, or cysts having multiple lumens. Further analysis revealed that abnormalities initiated at the first cell division and persisted throughout the entire cystogenesis process. For NUPL1-knockdown cells, abnormal cytogenesis largely arose from faulty cell divisions, notably monopolar spindles or spindles with poorly separated poles. For AVL9- or DENND5A-knockdown cells, abnormalities originated from both aberrant intracellular trafficking and defective mitosis. Moreover, while all knockdown clones displayed an accelerated rate of both cell proliferation and death, only AVL9- and DENND5A-knockdowns, but not NUPL1-knockdown, promoted cell migration. These observations indicate that NUPL1 contributes to bipolar spindle formation, whereas AVL9 and DENND5A participate in both intracellular trafficking and cell cycle progression. Our study shed lights on these genes’ normal cellular functions and on how their alteration contributes to carcinogenesis.

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