Silencing of connexin 43 suppresses invasion, migration and lung metastasis of rat hepatocellular carcinoma cells.
To reduce cancer mortality, understanding of mechanisms of cancer metastasis is crucial. We have established six rat hepatocellular carcinoma (HCC) cell lines, which exhibit differing metastatic potential to the lung after inoculation into the tail veins of nude mice. In the present experiment, we investigated the process of cell attachment to metastatic sites and possible regulating factors. One hour after inoculation, two of two HCC cell lines with high metastatic potential and one of two HCC cell lines with low metastatic potential exhibited many attached cells in the lung. One day after inoculation, lung metastatic foci were observed only with highly-metastatic cells with elevated connexin 43 (Cx43) expression as assessed by cDNA array analysis. Furthermore, 24 or 48 h after transfection of an siRNA targeting Cx43, in vitro invasion and migration were suppressed by 68% (P < 0.001) and 36% (P < 0.05) compared with control-siRNA transfected cells, despite no differences in cellular morphology, cell proliferation or apoptotic activity. Moreover, the number of metastatic nodules per lung area in nude mice was significantly (P < 0.01) reduced. In conclusion, suppression of Cx43 expression in tumor cells reduced in vitro migration and invasion capacity and in vivo metastatic ability so that Cx43 has potential as a molecular target for prevention of cancer metastasis with Cx43 overexpressing tumors.
Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. ogawa93@nihs.go.jp
Kumiko
K
Ogawa
Pornsiri
P
Pitchakarn
Shugo
S
Suzuki
Teera
T
Chewonarin
MingXi
M
Tang
Seishiro
S
Takahashi
Aya
A
Naiki-Ito
Shinya
S
Sato
Satoru
S
Takahashi
Makoto
M
Asamoto
Tomoyuki
T
Shirai
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000556:secondary; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D018031:Connexin 43 / Q000235:genetics*; D020868:Gene Silencing; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics* / Q000556:secondary*; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D051381:Rats
D018031:Connexin 43