Establishment and characterization of serial subpopulations with highly metastatic potential via different metastatic routes

Objective To establish the serial cell lines, derived from the same parental gallbladder cancer cell line GBC-SD, with highly metastatic potential via different routes and characterize their biological behaviors to understand the different metastasis mechanisms via lymph and blood. Methods The spleenliver metastasis model and footpad-inguinal lymph node metastasis model were established. GBC-SD was injected into spleen or footpad of nude mice. Then the highly metastasized subpopulations via lymph and blood were isolated. Their differences in morphology, genetic background, proliferation, migration, invasion and adhesion were revealed by comparing the lymphatic-disseminating and hematogenous-disseminating subpopulations with parental cells. Results The lymphatic-disseminating and hematogenous-disseminating subpopulations were successfully isolated and designated as GBC-SD/HL and GBC-SD/M3 respectively.They demonstrated the identical genetic background with GBC-SD. In comparison with parental cells, the hematogenous-disseminating subpopulation was morphologically characterized with epithelial-mesenchymal transition (EMT) while it was not shown in the lymphatic-disseminating subpopulation. Furthermore, the hematogenous-disseminating subpopulation showed the strongest migrating capacity but the lymphaticdisseminating subpopulation demonstrated a stronger invasive and adhesive ability. Conclusion The whole parental cell GBC-SD, hematogenous-metastasized subpopulation GBC-SD/M3 and lymphatic-disseminating subpopulation GBC-SD/HL is an ideal tool for metastatic mechanism study of gallbladder cancer. EMT plays an important role in hematogenous metastasis while lymphatic metastasis relies more on enhanced invasiveness and adhesion. It may be a target for interfering the lymphatic metastasis of gallbladder cancer. Key words: Gallbladder neoplasms;  Neoplasmic metastasis;  Subpopulation;  Biological behavior