JC virus mediates invasion and migration in colorectal metastasis.
BACKGROUND
JC Virus (JCV), a human polyomavirus, is frequently present in colorectal cancers (CRCs). JCV large T-Ag (T-Ag) expressed in approximately half of all CRC's, however, its functional role in CRC is poorly understood. We hypothesized that JCV T-Ag may mediate metastasis in CRC cells through increased migration and invasion.


METHODS
CRC cell lines (HCT116 and SW837) were stably transfected with JCV early transcript sequences cloned into pCR3 or empty vectors. Migration and invasion assays were performed using Boyden chambers. Global gene expression analysis was performed to identify genetic targets and pathways altered by T-Ag expression. Microarray results were validated by qRT-PCR, protein expression analyses and immunohistochemistry. Matching primary CRCs and liver metastases from 33 patients were analyzed for T-Ag expression by immunohistochemistry.


RESULTS
T-Ag expressing cell lines showed 2 to 3-fold increase in migration and invasion compared to controls. JCV T-Ag expression resulted in differential expression of several genetic targets, including genes that mediate cell migration and invasion. Pathway analysis suggested a significant involvement of these genes with AKT and MAPK signaling. Treatment with selective PI3K/AKT and MAPK pathway inhibitors resulted in reduced migration and invasion. In support of our in-vitro results, immunohistochemical staining of the advanced stage tumors revealed frequent JCV T-Ag expression in metastatic primary tumors (92%) as well as in their matching liver metastasis (73%).


CONCLUSIONS
These data suggest that JCV T-Ag expression in CRC associates with a metastatic phenotype, which may partly be mediated through the AKT/MAPK signaling pathway. Frequent expression of JCV T-Ag in CRC liver metastasis provides further clues supporting a mechanistic role for JCV as a possible mediator of cellular motility and invasion in CRC.
Link
Alexander
A
Division of Gastroenterology, Department of Internal Medicine, Charles A. Sammons Cancer Center and Baylor Research Institute, Baylor University Medical Center, Dallas, Texas, United States of America.
Shin
Sung Kwan
SK
Nagasaka
Takeshi
T
Balaguer
Francesc
F
Koi
Minoru
M
Jung
Barbara
B
Boland
C Richard
CR
Goel
Ajay
A
D000368:Aged; D000957:Antigens, Viral, Tumor / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology* / Q000821:virology*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007577:JC Virus / Q000187:drug effects / Q000502:physiology*; D008113:Liver Neoplasms / Q000556:secondary; D008297:Male; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014162:Transfection
D000957:Antigens, Viral, Tumor; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases