Our goal is to explore novel tumor suppressor mechanisms dependent on the integrity of primary cilia. Our preliminary data shows the absence of cilia in cholangiocarcinoma cells; therefore, ciliary dysfunction may be associated with cancer development. The mechanisms leading to ciliary reduction in these tumor cells as well as the consequences of such a lost remain unknown. We HYPOTHESIZE that the functional integrity of cholangiocyte primary cilia is required for the transduction of environmental stimuli, and generates intracellular signals that function as tumor suppressors. We propose that in cholangiocarcinoma, (i) decreased microRNAs expression (i.e. mir-433, mir-22, mir-141, mir-200) leads to overexpression of HDAC6, a cytoplasmic deacetylase that induces ciliary resorption, and the subsequent reduction of cholangiocyte primary cilia; and (ii) ciliary loss generates the disengagement between the environment and the cell interior resulting in derepression of tumorigenic factors and cancer development.
In Specific Aim #1 we will characterize the effect of ciliary loss on the normal cholangiocyte phenotype. Our working hypothesis, based upon preliminary data, is that primary cilia and the intracellular signals induced by their multisensory functions are constraining Hedgehog and MAPK pathways, which are involved in cancer development.
In Specific Aim #2 we will characterize the effect of specific miRNAs downregulated in CCA on cholangiocyte ciliary expression. Our working hypothesis is that the downregulation of mir-433, mir-22, mir-141, and/or mir-200 in CCA induces the overexpression of HDAC6 and the resorption of cilia. Finally, in Specific Aim #3 we will evaluate the effect of cilia restoration on tumor cells. Our working hypothesis is that this intervention isa potential approach for decreasing cell growth and dedifferentiation of cholangiocarcinoma cells. The results of the present proposal will provide novel information regarding the ciliary-dependent mechanisms controlling the proliferation of tumor cells; and will provide the foundation for a plausible anti-cancer therapeutic treatment based on the rescue of primary cilia architecture and function.

Public Health Relevance

The present proposal intends to explore novel tumor suppressor mechanisms dependent on the integrity of primary cilia. We hypothesized that the loss of primary cilia induces the disengagement between the environment and the cell interior resulting in derepression of tumorigenic factors and the development of cancer. Specifically we will focus our experiments on cholangiocarcinoma; a devastating disease with no effective therapeutic strategies available. Our efforts will provide the basic knowledge for the foundation of potential therapeutic approaches; based on the restoration of cilia architecture and/or the rescue of the intracellular signals generated by the multisensory functions of these organelles.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Exploratory/Developmental Grants (R21)
Project #
7R21CA166635-03
Application #
8976926
Study Section
Special Emphasis Panel (ZRG1-OBT-M (55))
Program Officer
Davani, Behrous
Project Start
2013-04-01
Project End
2015-03-31
Budget Start
2015-01-27
Budget End
2015-03-31
Support Year
3
Fiscal Year
2014
Total Cost
$93,993
Indirect Cost
$32,358
Name
University of Minnesota Twin Cities
Department
Type
Organized Research Units
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Gradilone, Sergio A; Pisarello, Maria J Lorenzo; LaRusso, Nicholas F (2017) Primary Cilia in Tumor Biology: The Primary Cilium as a Therapeutic Target in Cholangiocarcinoma. Curr Drug Targets 18:958-963
Gradilone, Sergio A; O'Hara, Steven P; Masyuk, Tetyana V et al. (2015) MicroRNAs and benign biliary tract diseases. Semin Liver Dis 35:26-35
Gradilone, Sergio A; Habringer, Stefan; Masyuk, Tatyana V et al. (2014) HDAC6 is overexpressed in cystic cholangiocytes and its inhibition reduces cystogenesis. Am J Pathol 184:600-8
Razumilava, Nataliya; Gradilone, Sergio A; Smoot, Rory L et al. (2014) Non-canonical Hedgehog signaling contributes to chemotaxis in cholangiocarcinoma. J Hepatol 60:599-605
Gradilone, Sergio A; Radtke, Brynn N; Bogert, Pamela S et al. (2013) HDAC6 inhibition restores ciliary expression and decreases tumor growth. Cancer Res 73:2259-70