Publications by authors named "Jerry J Fan"

4 Publications

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Ion Channels in Cancer: Orchestrators of Electrical Signaling and Cellular Crosstalk.

Rev Physiol Biochem Pharmacol 2020 Sep 8. Epub 2020 Sep 8.

Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada.

Ion channels are pore-forming transmembrane proteins that govern ion flux to regulate a myriad of biological processes in development, physiology, and disease. Across various types of cancer, ion channel expression and activity are often dysregulated. We review the contribution of ion channels to multiple stages of tumorigenesis based on data from in vivo model systems. As intertumoral and intratumoral heterogeneities are major obstacles in developing effective therapies, we provide perspectives on how ion channels in tumor cells and their microenvironment represent targetable vulnerabilities in the areas of tumor-stromal cell interactions, cancer neuroscience, and cancer mechanobiology.
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http://dx.doi.org/10.1007/112_2020_48DOI Listing
September 2020

Chloride intracellular channel 1 cooperates with potassium channel EAG2 to promote medulloblastoma growth.

J Exp Med 2020 05;217(5)

Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.

Ion channels represent a large class of drug targets, but their role in brain cancer is underexplored. Here, we identify that chloride intracellular channel 1 (CLIC1) is overexpressed in human central nervous system malignancies, including medulloblastoma, a common pediatric brain cancer. While global knockout does not overtly affect mouse development, genetic deletion of CLIC1 suppresses medulloblastoma growth in xenograft and genetically engineered mouse models. Mechanistically, CLIC1 enriches to the plasma membrane during mitosis and cooperates with potassium channel EAG2 at lipid rafts to regulate cell volume homeostasis. CLIC1 deficiency is associated with elevation of cell/nuclear volume ratio, uncoupling between RNA biosynthesis and cell size increase, and activation of the p38 MAPK pathway that suppresses proliferation. Concurrent knockdown of CLIC1/EAG2 and their evolutionarily conserved channels synergistically suppressed the growth of human medulloblastoma cells and Drosophila melanogaster brain tumors, respectively. These findings establish CLIC1 as a molecular dependency in rapidly dividing medulloblastoma cells, provide insights into the mechanism by which CLIC1 regulates tumorigenesis, and reveal that targeting CLIC1 and its functionally cooperative potassium channel is a disease-intervention strategy.
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http://dx.doi.org/10.1084/jem.20190971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7201926PMC
May 2020

A Feedforward Mechanism Mediated by Mechanosensitive Ion Channel PIEZO1 and Tissue Mechanics Promotes Glioma Aggression.

Neuron 2018 11 18;100(4):799-815.e7. Epub 2018 Oct 18.

Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 3E1, Canada. Electronic address:

Alteration of tissue mechanical properties is a physical hallmark of solid tumors including gliomas. How tumor cells sense and regulate tissue mechanics is largely unknown. Here, we show that mechanosensitive ion channel Piezo regulates mitosis and tissue stiffness of Drosophila gliomas, but not non-transformed brains. PIEZO1 is overexpressed in aggressive human gliomas and its expression inversely correlates with patient survival. Deleting PIEZO1 suppresses the growth of glioblastoma stem cells, inhibits tumor development, and prolongs mouse survival. Focal mechanical force activates prominent PIEZO1-dependent currents from glioma cell processes, but not soma. PIEZO1 localizes at focal adhesions to activate integrin-FAK signaling, regulate extracellular matrix, and reinforce tissue stiffening. In turn, a stiffer mechanical microenvironment elevates PIEZO1 expression to promote glioma aggression. Therefore, glioma cells are mechanosensory in a PIEZO1-dependent manner, and targeting PIEZO1 represents a strategy to break the reciprocal, disease-aggravating feedforward circuit between tumor cell mechanotransduction and the aberrant tissue mechanics. VIDEO ABSTRACT.
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http://dx.doi.org/10.1016/j.neuron.2018.09.046DOI Listing
November 2018

A metabolic function of FGFR3-TACC3 gene fusions in cancer.

Nature 2018 01 3;553(7687):222-227. Epub 2018 Jan 3.

Institute for Cancer Genetics, Columbia University Medical Center, New York, New York 10032, USA.

Chromosomal translocations that generate in-frame oncogenic gene fusions are notable examples of the success of targeted cancer therapies. We have previously described gene fusions of FGFR3-TACC3 (F3-T3) in 3% of human glioblastoma cases. Subsequent studies have reported similar frequencies of F3-T3 in many other cancers, indicating that F3-T3 is a commonly occuring fusion across all tumour types. F3-T3 fusions are potent oncogenes that confer sensitivity to FGFR inhibitors, but the downstream oncogenic signalling pathways remain unknown. Here we show that human tumours with F3-T3 fusions cluster within transcriptional subgroups that are characterized by the activation of mitochondrial functions. F3-T3 activates oxidative phosphorylation and mitochondrial biogenesis and induces sensitivity to inhibitors of oxidative metabolism. Phosphorylation of the phosphopeptide PIN4 is an intermediate step in the signalling pathway of the activation of mitochondrial metabolism. The F3-T3-PIN4 axis triggers the biogenesis of peroxisomes and the synthesis of new proteins. The anabolic response converges on the PGC1α coactivator through the production of intracellular reactive oxygen species, which enables mitochondrial respiration and tumour growth. These data illustrate the oncogenic circuit engaged by F3-T3 and show that F3-T3-positive tumours rely on mitochondrial respiration, highlighting this pathway as a therapeutic opportunity for the treatment of tumours with F3-T3 fusions. We also provide insights into the genetic alterations that initiate the chain of metabolic responses that drive mitochondrial metabolism in cancer.
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http://dx.doi.org/10.1038/nature25171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5771419PMC
January 2018