The Research Of The Mechanism Of C-Met Signaling Pathway To Maintain The "Stem-ness" In CD44v6-positive Liver Cancer Stem Cells Department Of Gastroenterology, Tongji Hospital, Tongji Medical College, Hust

Objective: Among the CD44 isoforms, to identify and study the cancer stem marker of HCC. Then we explored the relationship between the c-Met pathway and the stem characteristic of CD44v6+ cells.Method: We sorted the CD44+ cells and CD44v6+ cells from PLC/PRF/5 cell line and SNU398 cell line respectively. Furthermore, the stem cell-like characteristic of CD44+ cells and CD44v6+ cells were analyzed using sphere and colony formation assay, tumorigenicity in NOD/SCID mice, invasion and migration assay and chemosensitivity assay, respectively. Finally, the CD44v6 was identified as the cancer stem cell marker of HCC by in vitro and vivo assays. Then the expression of stem related proteins(Oct4, c-Myc and Nanog) and the transcription factors(Snail and Twist1) in EMT of the cells with c-Met pathway inhibited by PHA665752 were detected by Western Blotting assay. The immunhistochemistry was used to detect the expression of CD44v6, Nanog, c-Met and p-Met on the carcinoma and para-carcinoma tissue of human HCC clinical specimens.Results: The CD44+ and CD44v6+ cells were successfully sorted by magnetic sorting. Comparing with the pan CD44- cells, the cell subset of pan CD44+ did not preferentially show the stem characteristic of cancer stem cells. However, the CD44v6+ cells improved the ability of tumorigenic, metastatic and chemotherapy resistant of cancer cells. And the expression of stem related proteins(Oct4, c-Myc and Nanog) and the transcription factors(Snail and Twist1) in EMT can be regulated by c-Met/CD44v6 pathway while the c-Met pathway was inhibited by PHA665752.Conclusion: The collective results suggested that CD44+ cell subsets did not share many features of CSCs, but CD44v6 can be putative cancer stem cell markers in established human HCC cell lines. And the expression of stem related proteins can be regulated by c-Met/CD44v6 pathway. Moreover, the c-Met/CD44v6 pathway has relationship with the activation of EMT.