Pancreatic More Features And Mechanism Of Cell Chemosensitivity Ball-like Bodies

Pancreatic carcinoma is a group of cancer that seriously threatens human life, to which chemotherapy is one of the most important treatments. Although in recent years, novel chemotherapeutic agents and regimens have been developed, drug resistance has been a chief cause of the failure of chemotherapy. The chemosensitivity tests for carcinoma used in the past were based on monolayer cultured cells in the two-dimensional model, while human pancreatic cancer cells in vivo survive in a three-dimensional growing pattern. Monolayer cultured cells model neglects the different characteristics between an entire tumor and a single tumor cell, the interactions between tumor cells and the impacts of the microenvironment. Monolayer cultured cell model can not mimic the environment in vivo, nor can it provide a reliable platform for pancreatic cancer chemosensitivity test in vitro. More and more researches in recent years show that the interaction between tumor cells and the microenvironment is the basis for tumor growth and survival, which may be involved in the regulation of drug effects and the incidence of anti-cancer drug resistance. In this study, two pancreatic cell lines were cultured in collagen type I to form multicellular spheroid (MCS), of which the sensitivity characteristics to chemotherapy were studied. Chemosensitivity of clinical cancer specimens including pancreatic carcinoma were assessed with collagen gel droplet culture drug-sensitivity test (CD-DST).In part1of this study, two pancreatic cell lines, SW1990and ASPC-1, were cultured in collagen type I to form MCS. The growth curves of the two cell lines in2-D and3-D systems were made respectively. Then three groups were established, including MCS model, dispersed model in collagen type I3-D system and monolayer model in2-D system. Comparing the suppression rate between MCS and the other two systems after the treatment of5-Fu and GEM, we found the chemosensitivity of MCS was lower than that of the other two, which suggested multicellular resistance existed in the MCS of the two pancreatic cell lines. After that, the apoptosis rate detected by flow cytometry analyses of Annexin V-FITC/PI stained cells confirmed the drug-suppression result. Further analysis indicated a decrease in S-phase fraction of MCS compared with monolayer cultured cells, witch may be one factor of the multicellular resistance.In part2, we cultured the primary cells from the clinical cancer specimens, of which the sensitivity to chemotherapy were examined in vitro by collagen-gel droplet culture drug-sensitivity test (CD-DST). At the same time, we isolated the fibrocyte-like cells in the primary cultured cells, which proved to be pancreatic stellate cells by a-SMA immunofluorescent staining.