RhoC GTPase is required for PC-3 prostate cancer cell invasion but not motility.
It is projected that in 2005, approximately 220 900 men will be newly diagnosed with carcinoma of the prostate (CaP). Men who are diagnosed with locally advanced or metastatic disease undergo androgen ablation therapy and most will relapse and progress within 18 months. Metastasis to bone is the major clinical concern during CaP progression, as it is associated with intractable pain, bone fracture and paralysis resulting from spinal cord compression. Therefore, an understanding of the key mechanisms involved in CaP cell bone metastasis is vital to development of novel treatments. The Rho GTPases are molecular switches involved in cell survival, motility and invasion. Increased expression of RhoC GTPase is linked to enhanced metastatic potential in multiple cancers; however, the role of RhoC GTPase in CaP metastasis has not been addressed. In the current study, we demonstrate that RhoC GTPase is expressed and active in PC-3 CaP cells. RhoC inhibition, either pharmacologically with C3 exotransferase or molecularly through expression of a dominant-negative RhoC, promotes IGF-I stimulated random motility but decreases in vitro invasion and experimental metastases. Inhibition of RhoC activity results in drastic morphologic changes and alterations in the expression and distribution of focal adhesion-related proteins. These data suggest that RhoC inhibition leads to activation of other GTPases involved in nondirected motility and that expression of active RhoC is required for the invasive phenotype of PC-3 cells.
Yao
H
H
Division of Hematology/Oncology, The Department of Internal Medicine, The University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-0548, USA.
Dashner
E J
EJ
van Golen
C M
CM
van Golen
K L
KL
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000199:Actins / Q000032:analysis; D001905:Botulinum Toxins / Q000494:pharmacology; D045744:Cell Line, Tumor; D002465:Cell Movement; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000032:analysis; D020690:GTPase-Activating Proteins / Q000032:analysis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008297:Male; D009361:Neoplasm Invasiveness; D011471:Prostatic Neoplasms / Q000473:pathology*; D016596:Vinculin / Q000032:analysis; D020764:cdc42 GTP-Binding Protein / Q000032:analysis; D020830:rac1 GTP-Binding Protein / Q000032:analysis; D020741:rho GTP-Binding Proteins / Q000502:physiology*; D000075024:rhoC GTP-Binding Protein
D000199:Actins; C430213:GIT2 protein, human; D020690:GTPase-Activating Proteins; D016596:Vinculin; D007334:Insulin-Like Growth Factor I; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D051416:Focal Adhesion Protein-Tyrosine Kinases; D001905:Botulinum Toxins; C066690:RHOC protein, human; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D000075024:rhoC GTP-Binding Protein