Alternative mRNA splicing of liver intestine-cadherin in hepatocellular carcinoma.
OBJECTIVE
To identify alternative splicing of the liver intestine-cadherin (LI-cadherin) gene in hepatocellular carcinoma (HCC) and correlate its aberrant expression with clinical outcomes.


METHODS
Reverse transcription-PCR (RT-PCR) and quantitative real-time RT-PCR were used to examine alternative mRNA splicing and mRNA level of LI-cadherin in 50 paired tumor-peritumor tissues of 50 HCC and 8 normal liver specimens. The minigene exon-trapping strategy was employed to investigate the splicing mechanism introduced by nucleotide polymorphisms. Association of LI-cadherin splicing with tumor venous infiltration, first-year tumor recurrence, and overall survival after partial hepatectomy were determined.


RESULTS
Alternative mRNA splicing of LI-cadherin was identified in half of the HCC specimens. Sequencing analysis indicated the loss of exon 7 in the spliced LI-cadherin gene. LI-cadherin mRNA was up-regulated from 2.58-fold to 800-fold in over 80% of HCC samples when compared with normal liver by quantitative PCR. Furthermore, nucleotide polymorphisms were identified in putative branch point at IVS6 + 35 (intron 6) as well as in coding sequence 651 (exon 6) in HCC tissues, which may affect alternative mRNA splicing. Clinically, those patients who harbored the alternative splicing of LI-cadherin were strongly associated with shorter overall survival time (P < 0.01) as well as higher incidences of tumor recurrences and venous infiltration (both P < 0.05) after hepatectomy.


CONCLUSIONS
Over-expression of LI-cadherin was frequently detected in liver cancer patients. Aberrant alternative splicing of LI-cadherin was detected in 50% of HCC specimens and its clinical significance hinted at early tumor recurrence and poor overall survival of HCC patients.
Wang
Xiao Qi
XQ
Department of Surgery, University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
Luk
John M
JM
Leung
Pauline P
PP
Wong
Bonnie W
BW
Stanbridge
Eric J
EJ
Fan
Sheung Tat
ST
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000378:metabolism; D002522:Chlorocebus aethiops; D005091:Exons / Q000235:genetics; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D014162:Transfection
C490584:CDH17 protein, human; D015820:Cadherins; D012333:RNA, Messenger; D012334:RNA, Neoplasm