A splice variant of the human ion channel TRPM2 modulates neuroblastoma tumor growth through hypoxia-inducible factor (HIF)-1/2α.
The calcium-permeable ion channel TRPM2 is highly expressed in a number of cancers. In neuroblastoma, full-length TRPM2 (TRPM2-L) protected cells from moderate oxidative stress through increased levels of forkhead box transcription factor 3a (FOXO3a) and superoxide dismutase 2. Cells expressing the dominant negative short isoform (TRPM2-S) had reduced FOXO3a and superoxide dismutase 2 levels, reduced calcium influx in response to oxidative stress, and enhanced reactive oxygen species, leading to decreased cell viability. Here, in xenografts generated with SH-SY5Y neuroblastoma cells stably expressing TRPM2 isoforms, growth of tumors expressing TRPM2-S was significantly reduced compared with tumors expressing TRPM2-L. Expression of hypoxia-inducible factor (HIF)-1/2α was significantly reduced in TRPM2-S-expressing tumor cells as was expression of target proteins regulated by HIF-1/2α including those involved in glycolysis (lactate dehydrogenase A and enolase 2), oxidant stress (FOXO3a), angiogenesis (VEGF), mitophagy and mitochondrial function (BNIP3 and NDUFA4L2), and mitochondrial electron transport chain activity (cytochrome oxidase 4.1/4.2 in complex IV). The reduction in HIF-1/2α was mediated through both significantly reduced HIF-1/2α mRNA levels and increased levels of von Hippel-Lindau E3 ligase in TRPM2-S-expressing cells. Inhibition of TRPM2-L by pretreatment with clotrimazole or expression of TRPM2-S significantly increased sensitivity of cells to doxorubicin. Reduced survival of TRPM2-S-expressing cells after doxorubicin treatment was rescued by gain of HIF-1 or -2α function. These data suggest that TRPM2 activity is important for tumor growth and for cell viability and survival following doxorubicin treatment and that interference with TRPM2-L function may be a novel approach to reduce tumor growth through modulation of HIF-1/2α, mitochondrial function, and mitophagy.
From the Departments of Pediatrics.
Shu-jen
SJ
Chen
the Center for Translational Medicine and Departments of Biochemistry and.
Nicholas E
NE
Hoffman
the Center for Translational Medicine and Departments of Biochemistry and.
Santhanam
S
Shanmughapriya
From the Departments of Pediatrics.
Lei
L
Bao
From the Departments of Pediatrics.
Kerry
K
Keefer
From the Departments of Pediatrics.
Kathleen
K
Conrad
Departments of Biochemistry and.
Salim
S
Merali
From the Departments of Pediatrics, Pharmacology.
Yoshinori
Y
Takahashi
Research Resources, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033 and.
Thomas
T
Abraham
From the Departments of Pediatrics.
Iwona
I
Hirschler-Laszkiewicz
the Center for Translational Medicine and.
JuFang
J
Wang
the Center for Translational Medicine and.
Xue-Qian
XQ
Zhang
the Center for Translational Medicine and.
Jianliang
J
Song
Departments of Biochemistry and.
Carlos
C
Barrero
Cellular and Molecular Physiology, and.
Yuguang
Y
Shi
Pharmacology, Biochemistry and Molecular Biology, Institute for Personalized Medicine, and.
Yuka Imamura
YI
Kawasawa
Pathology.
Michael
M
Bayerl
From the Departments of Pediatrics.
Tianyu
T
Sun
From the Departments of Pediatrics.
Mustafa
M
Barbour
From the Departments of Pediatrics, Pharmacology.
Hong-Gang
HG
Wang
the Center for Translational Medicine and Departments of Biochemistry and.
Muniswamy
M
Madesh
the Center for Translational Medicine and Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.
Joseph Y
JY
Cheung
From the Departments of Pediatrics, Biochemistry and Molecular Biology, bmiller3@psu.edu.
Barbara A
BA
Miller
D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D001343:Autophagy; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D015536:Down-Regulation; D004317:Doxorubicin / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial; D008564:Membrane Potentials; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D020033:Protein Isoforms / Q000502:physiology; D021381:Protein Transport; D050053:TRPM Cation Channels / Q000502:physiology*; D047368:Tumor Burden; D000099162:Endothelial PAS Domain-Containing Protein 1
D000903:Antibiotics, Antineoplastic; D051792:Basic Helix-Loop-Helix Proteins; D004317:Doxorubicin; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D020033:Protein Isoforms; D050053:TRPM Cation Channels; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human; C121934:TRPM2 protein, human
Hypoxia-inducible Factor (HIF); Mitochondria; Mitophagy; Neuroblastoma; Oxidative Stress; TRP; TRPM