GLUT12 promotes prostate cancer cell growth and is regulated by androgens and CaMKK2 signaling.

Despite altered metabolism being an accepted hallmark of cancer, it is still not completely understood which signaling pathways regulate these processes. Given the central role of androgen receptor (AR) signaling in prostate cancer, we hypothesized that AR could promote prostate cancer cell growth in part through increasing glucose uptake via the expression of distinct glucose transporters. Here, we determined that AR directly increased the expression of SLC2A12, the gene that encodes the glucose transporter GLUT12. In support of these findings, gene signatures of AR activity correlated with SLC2A12 expression in multiple clinical cohorts. Functionally, GLUT12 was required for maximal androgen-mediated glucose uptake and cell growth in LNCaP and VCaP cells. Knockdown of GLUT12 also decreased the growth of C4-2, 22Rv1 and AR-negative PC-3 cells. This latter observation corresponded with a significant reduction in glucose uptake, indicating that additional signaling mechanisms could augment GLUT12 function in an AR-independent manner. Interestingly, GLUT12 trafficking to the plasma membrane was modulated by calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2)-5'-AMP-activated protein kinase (AMPK) signaling, a pathway we previously demonstrated to be a downstream effector of AR. Inhibition of CaMKK2-AMPK signaling decreased GLUT12 translocation to the plasma membrane by inhibiting the phosphorylation of TBC1D4, a known regulator of glucose transport. Further, AR increased TBC1D4 expression. Correspondingly, expression of TBC1D4 correlated with AR activity in prostate cancer patient samples. Taken together, these data demonstrate that prostate cancer cells can increase the functional levels of GLUT12 through multiple mechanisms to promote glucose uptake and subsequent cell growth.

White MA ，Tsouko E ，Lin C ，Rajapakshe K ，Spencer JM ，Wilkenfeld SR ，Vakili SS ，Pulliam TL ，Awad D ，Nikolos F ，Katreddy RR ，Kaipparettu BA ，Sreekumar A ，Zhang X ，Cheung E ，Coarfa C ，Frigo DE ... -  《-》

Nucleoporin 62 and Ca(2+)/calmodulin dependent kinase kinase 2 regulate androgen receptor activity in castrate resistant prostate cancer cells.

Re-activation of the transcriptional activity of the androgen receptor (AR) is an important factor mediating progression from androgen-responsive to castrate-resistant prostate cancer (CRPC). However, the mechanisms regulating AR activity in CRPC remain incompletely understood. Ca(2+) /calmodulin-dependent kinase kinase (CaMKK) 2 was previously shown to regulate AR activity in androgen-responsive prostate cancer cells. Our objective was to further explore the basis of this regulation in CRPC cells. The abundance of CaMKK2 in nuclear fractions of androgen-responsive prostate cancer and CRPC, cells were determined by subcellular fractionation and Western blotting. CaMKK2 association with nuclear pore complexes (NPCs) and nucleoporins (Nups) including Nup62, were imaged by structured illumination and super-resolution fluorescence microscopy and co-immunoprecipitation, respectively. The abundance and subcellular localization of CaMKK2 and Nup62 in human clinical specimens of prostate cancer was visualized by immunohistochemistry. The role of Nups in the growth and viability of CRPC cells was assessed by RNA interference and cell counting. The involvement of CaMKK2 and Nup62 in regulating AR transcriptional activity was addressed by RNA interference, chromatin immunoprecipitation, androgen response element reporter assay, and Western blotting. CaMKK2 was expressed at higher levels in the nuclear fraction of CPRC C4-2 cells, than in that of androgen-responsive LNCaP cells. In C4-2 cells, CaMKK2 associated with NPCs of the nuclear envelope and physically interacted with Nup62. CaMKK2 and Nup62 demonstrated pronounced, and similar increases in both expression and perinuclear/nuclear localization in human clinical specimens of advanced prostate cancer relative to normal prostate. Knockdown of Nup62, but not of Nups, 98 or 88, reduced growth and viability of C4-2 cells. Knockdown of Nup62 produced a greater reduction of the growth and viability of C4-2 cells than of non-neoplastic RWPE-1 prostatic cells. Nup62, CaMKK2, and the AR were recruited to androgen response elements of the AR target genes, prostate specific antigen, and transmembrane protease, serine 2. Knockdown of CaMKK2 and Nup62 reduced prostate specific antigen expression and AR transcriptional activity driven by androgen response elements from the prostate-specific probasin gene promoter. Nup62 and CaMKK2 are required for optimal AR transcriptional activity and a potential mechanism for AR re-activation in CRPC.

Karacosta LG ，Kuroski LA ，Hofmann WA ，Azabdaftari G ，Mastri M ，Gocher AM ，Dai S ，Hoste AJ ，Edelman AM ... -  《-》

A regulatory feedback loop between Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and the androgen receptor in prostate cancer progression.

Karacosta LG ，Foster BA ，Azabdaftari G ，Feliciano DM ，Edelman AM ... -  《-》

Androgens regulate prostate cancer cell growth via an AMPK-PGC-1α-mediated metabolic switch.

Tennakoon JB ，Shi Y ，Han JJ ，Tsouko E ，White MA ，Burns AR ，Zhang A ，Xia X ，Ilkayeva OR ，Xin L ，Ittmann MM ，Rick FG ，Schally AV ，Frigo DE ... -  《-》

Inhibition of CAMKK2 impairs autophagy and castration-resistant prostate cancer via suppression of AMPK-ULK1 signaling.

Lin C ，Blessing AM ，Pulliam TL ，Shi Y ，Wilkenfeld SR ，Han JJ ，Murray MM ，Pham AH ，Duong K ，Brun SN ，Shaw RJ ，Ittmann MM ，Frigo DE ... -  《-》