Ubiquitous mitochondrial creatine kinase is overexpressed in the conditioned medium and the extract of LNCaP lineaged androgen independent cell lines and facilitates prostate cancer progression.
BACKGROUND
Androgen independent prostate cancer (AIPC) is not responsive to androgen ablation therapy. The biomarkers of AIPC are lack. Numerous proteomics studies have focused on finding new markers of AIPC and exploring their possible functions, but little is known about the difference between conditioned medium (CM) from AIPC and androgen dependent prostate cancer (ADPC) cells.


METHODS
We performed a proteome analysis of CM from LNCaP, C4-2, and C4-2B cells by a two dimensional electrophoresis based technology. Western blots and immunohistochemical studies were employed to explore the expression pattern of the identified protein in prostate cancer cell lines and clinical specimens, respectively. Then we examined the possible roles and mechanisms of the ubiquitous mitochondrial creatine kinase (uMtCK) in vitro.


RESULTS
Besides prostate specific antigen (PSA) and insulin-like growth factor binding protein-2 (IGFBP2), uMtCK was identified in the CM of AIPC cells. uMtCK was up-regulated in AIPC cells and in human prostate cancer tissues at WHO grade III. Stably transfected exogenous uMtCK showed a growth promoting effect rather than mock vector in LNCaP cells, with or without bicalutamide in culture medium. Further assays showed that higher degrees of ROS generation and Akt signaling pathway activation in LNCaP-uMtCK than in LNCaP-neo cells.


CONCLUSIONS
We showed that uMtCK could be easily detected in CM of LNCaP lineaged AIPC cells. Exogenous uMtCK in LNCaP cells surprisingly contributed to overproduction of ROS, activation of Akt signaling pathway and more aggressive phenotypes including androgen independence development.
The Laboratory of Molecular Oncology, Beijing Institute of Biotechnology, Beijing 100850, P.R. China.
Bo
B
Pang
Hui
H
Zhang
Jian
J
Wang
Wen-Zheng
WZ
Chen
Shan-Hu
SH
Li
Qing-Guo
QG
Shi
Rei-Xia
RX
Liang
Bang-Xiang
BX
Xie
Rui-Qin
RQ
Wu
Xiao-Long
XL
Qian
Lan
L
Yu
Qi-Man
QM
Li
Cui-Fen
CF
Huang
Jian-Guang
JG
Zhou
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D000595:Amino Acid Sequence; D000728:Androgens / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D052281:Creatine Kinase, Mitochondrial Form / Q000032:analysis / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000378:metabolism*; D018450:Disease Progression; D006801:Humans; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
D000728:Androgens; D014408:Biomarkers, Tumor; D017077:Culture Media, Conditioned; D018971:Insulin-Like Growth Factor Binding Protein 2; D017382:Reactive Oxygen Species; D051057:Proto-Oncogene Proteins c-akt; D052281:Creatine Kinase, Mitochondrial Form; D017430:Prostate-Specific Antigen