Function Study Of Aberrant Hugl-1Variants In Hepatocellular Carcinoma

Cell polarity, which is fundamental to many aspects of cell and developmental biology, is involved in the processes of asymmetrical distribution of molecules, cell shape and asymmetrical cellular organization. And Cell polarity which is fundamental to many aspects of cell and developmental biology, such as asymmetrical and symmetrical division, neuronal transduction cell migration. Disruption of cell polarity will result in severe diseases, tumorgenesis and metastasis.The lethal giant larvae (lgl) gene was first identified in Drosophila and characterized as a tumor suppressor gene. Lgl function is reported to be essential for the development of polarized epithelia cell polarityRecent studies have shown that expression of Hugl-1is reduced in a high proportion of breast cancers, prostate cancers,lung cancers, melanomas, and ovarian cancers, and reduced expression of human homologue of Lgl, Hugl-1, has been reported to be involved in development and progression of human colon cancer, implying a tumor suppressor role for Hugl-1in human cancer.In order to characterize Hugl-1and to determine the clinical significance of Hugl-1alterations in hepatocellular carcinoma(HCC), sequence alterations as well as expression of Hugl-1from80HCC specimens and5HCC cell lines were analyzed, which revealed that aberrant splicing of Hugl-1is associated with hepatocellular carcinoma progression. Overexpression of two representative HCC-derived aberrant Hugl-1variants (Hugl-1/△1414-1567/1667-1959. or Hugl-1/△1190-1508)promoted HCC cell migration, invasion, and tumorigenicity in nude mice. However, how mechanism of Hugl-1in tumorigenesis remains to be clarified.To better understand the molecular basis of the role of Hugl-1in human cancer, Tet-On advanced inducible double-stable MDCK II cell lines were constructed.Wound healing assays indicated that cell clones expressing Hugl-1exhibited a strong reduction in migratory potential when compared with vector-transfectcd cells. Clones expressing Hugl-1/△1414-1567/1667-1959or Hugl-1/△1190-1508showed greatly increased migratory potential. We also founded that when Tet-On advanced inducible double-stable MDCK II cell lines were seeded in collage I Hugl-1and aberrant Hugl-1variants (Hugl-1/△1414-1567/1667-1959or Hugl-1/△1190-1508) localized to the basolateral region and colocalized with E-cadherin. In order to find genes associate with hugl-1, stable expression of EGFP-tagged Hugl-1/wt, representative HCC-derived Hugl-1splice variants, or EGFP in SK-HEP-1cells were established.