Antimetastatic effect of salvicine on human breast cancer MDA-MB-435 orthotopic xenograft is closely related to Rho-dependent pathway.
OBJECTIVE
Salvicine is a novel DNA topoisomerase II inhibitor with potent anticancer activity. In present study, the effect of salvicine against metastasis is evaluated using human breast carcinoma orthotopic metastasis model and its mechanism is further investigated both in animal and cellular levels.


METHODS
The MDA-MB-435 orthotopic xenograft model was applied to detect the antimetastatic effect of salvicine. Potential target candidates were detected and analyzed by microarray technology. Candidates were verified and explored by reverse transcription-PCR and Western blot. Salvicine activities on stress fiber formation, invasion, and membrane translocation were further investigated by immunofluorescence, invasion, and ultracentrifugal assays.


RESULTS
Salvicine significantly reduced the lung metastatic foci of MDA-MB-435 orthotopic xenograft, without affecting primary tumor growth obviously. A comparison of gene expression profiles of primary tumors and lung metastatic focus between salvicine-treated and untreated groups using the CLOTECH Atlas human Cancer 1.2 cDNA microarray revealed that genes involved in tumor metastasis, particularly those closely related to cell adhesion and motility, were obviously down-regulated, including fibronectin, integrin alpha3, integrin beta3, integrin beta5, FAK, paxillin, and RhoC. Furthermore, salvicine significantly down-regulated RhoC at both mRNA and protein levels, greatly inhibited stress fiber formation and invasiveness of MDA-MB-435 cells, and markedly blocked translocation of both RhoA and RhoC from cytosol to membrane.


CONCLUSIONS
The unique antimetastatic action of salvicine, particularly its specific modulation of cell motility in vivo and in vitro, is closely related to Rho-dependent signaling pathway.
Lang
Jing-Yu
JY
Division of Antitumor Pharmacology, State Key Laboratory of Drug Research, Division of Phytochemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, PR China.
Chen
Hua
H
Zhou
Jin
J
Zhang
Yi-Xiang
YX
Zhang
Xiong-Wen
XW
Li
Mei-Hong
MH
Lin
Li-Ping
LP
Zhang
Jin-Sheng
JS
Waalkes
Michael P
MP
Ding
Jian
J
D000818:Animals; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000517:prevention & control / Q000556:secondary; D008246:Lysophospholipids / Q000494:pharmacology; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009285:Naphthoquinones / Q000494:pharmacology* / Q000627:therapeutic use; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D022502:Stress Fibers / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays / Q000379:methods*; D018631:ras Proteins; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism; D000075024:rhoC GTP-Binding Protein
D008246:Lysophospholipids; D009285:Naphthoquinones; D012333:RNA, Messenger; C122096:salvicine; C066690:RHOC protein, human; C512911:Rhoc protein, mouse; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D000075024:rhoC GTP-Binding Protein; C032881:lysophosphatidic acid