Novel role of cold/menthol-sensitive transient receptor potential melastatine family member 8 (TRPM8) in the activation of store-operated channels in LNCaP human prostate cancer epithelial cells.
Recent cloning of a cold/menthol-sensitive TRPM8 channel (transient receptor potential melastatine family member 8) from rodent sensory neurons has provided the molecular basis for the cold sensation. Surprisingly, the human orthologue of rodent TRPM8 also appears to be strongly expressed in the prostate and in the prostate cancer-derived epithelial cell line, LNCaP. In this study, we show that despite such expression, LNCaP cells respond to cold/menthol stimulus by membrane current (I(cold/menthol)) that shows inward rectification and high Ca(2+) selectivity, which are dramatically different properties from "classical" TRPM8-mediated I(cold/menthol). Yet, silencing of endogenous TRPM8 mRNA by either antisense or siRNA strategies suppresses both I(cold/menthol) and TRPM8 protein in LNCaP cells. We demonstrate that these puzzling results arise from TRPM8 localization not in the plasma, but in the endoplasmic reticulum (ER) membrane of LNCaP cells, where it supports cold/menthol/icilin-induced Ca(2+) release from the ER with concomitant activation of plasma membrane (PM) store-operated channels (SOC). In contrast, GFP-tagged TRPM8 heterologously expressed in HEK-293 cells target the PM. We also demonstrate that TRPM8 expression and the magnitude of SOC current associated with it are androgen-dependent. Our results suggest that the TRPM8 may be an important new ER Ca(2+) release channel, potentially involved in a number of Ca(2+)- and store-dependent processes in prostate cancer epithelial cells, including those that are important for prostate carcinogenesis, such as proliferation and apoptosis.
Thebault
Stéphanie
S
Laboratoire de Physiologie Cellulaire, INSERM EMI 0228, USTL SN3, 59655 Villeneuve d'Ascq, France.
Lemonnier
Loïc
L
Bidaux
Gabriel
G
Flourakis
Matthieu
M
Bavencoffe
Alexis
A
Gordienko
Dimitri
D
Roudbaraki
Morad
M
Delcourt
Philippe
P
Panchin
Yuri
Y
Shuba
Yaroslav
Y
Skryma
Roman
R
Prevarskaya
Natalia
N
D000818:Animals; D001483:Base Sequence; D020013:Calcium Signaling; D002460:Cell Line; D045744:Cell Line, Tumor; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015870:Gene Expression; D020868:Gene Silencing; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008610:Menthol / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D018076:DNA, Complementary; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011993:Recombinant Fusion Proteins; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human; D008610:Menthol