An Experimental Study Of Targeted Immunotherapy With Mouse Liver Cancer Stem/Progenitor Cells

Background: An existing study have shown that tumor stem cells is one ofthe causes of tumor development. Currently, targetde immunotherapy with tumorstem cells was not safe because the immune cells were difficult to identify originaltumor stem cells and normal tissue stem cells, so easily dose the side effect ofimmune response of systemic. But zhe cells which rapided into cell division statusand retain the the characteristic cell subsets may be progenitor cells, it haveimportant biological significance and clinical significance of formation anddevelopment of tumer. Therefore, the tumor progenitor cells can became aspecific target for cancer therapy, and provide a new approach of cancerimmunotherapy.Objective: To define the contents of different stem characteristic subsets inH22cells based on the high expression of ALDH. Preparation of DC vaccineinduced tumor-specific CTLs. Evaluate the therapeutic effect. Lay the foundationfor targeted cancer therapy of stem/progenitor cells.Methods:1) We identified the ALDH expression by FCM in cell line cellsof Kunming Mouse Liver cancer H22, Gastric cancer BGC-823, Colon cancerLS-174T, Liver cancer SMMC-7721, Pancreatic cancer SW-1990and Panc-1;2)We isolated ALDH^high, ALDH^lowand ALDH^negsubsets by level of ALDHexpression in the ALDH+cells;3) Analyzed CD133&CD44of ALDH^high,ALDH^lowand ALDH^negsubsets;4) Analyzed the cell cycle of ALDH^high,ALDH^lowand ALDH^negsubsets;5) The spheres were induced by incubation ofdifferent stem characteristic subsets cells in the mTeSR1medium;6) The differentstem characteristic subsets cells tumorigenesis were tested in Kunming mice at2×10²and2×10⁴cells;7) Preparation of CTLs were by antigen of H22differentsubsets cells, treatment km mice which tumorigenic by H22cells, and calculatedthe inhibitory rate, spleen index and thymus index.Results:1) The expression of ALDH in H22,LS-174T, SW-1990andPanc-1was positive but negative in BGC-823and SMMC-7721,2) In H22cell, it was identified of ALDH^high，ALDH^lowand ALDH^negsubsets seen by thedifference of ALDH;3) the propotion of CD133&CD44in ALDH^high，ALDH^lowand ALDH^negsubsets of H22cell was decreasing;4) In the observation of H22cell, ALDH^highsubset existed in the G0/G1phase, ALDH^lowsubset was mainly inthe S phase and ALDH^negsubset largely appeared in the G2/M phase;5)ALDH^highsubsets can form a stem cell sphere， but the ALDH^lowand ALDH^negsubsets can not be formed;6) The mean tumor volume of ALDH^lowsubsets was0.2cm³in2×10²cells group, and the mean tumor volume of ALDH^lowsubsets was0.25cm³in2×10⁴cells group. The growth of ALDH^lowsubsets was better than theother subsets.7) ALDH^low-CTL cells inhibition rate of71%（P<0.01）, higher thanALDH^high-CTL and ALDH^neg-CTL cells, but spleen index and thymus index wasno significant in three groups.Conclusions:1) The expression of ALDH in H22, LS-174T, SW-1990andPanc-1was positive;2) We found that existed a specific subsets between the stemcells and the normal cells in cancer cells;3) Progenitor cells kept in the H22cells,it was a key cell subsets of tumor occurrence and development, and had a higherinhibitory rate of CTL cells. It provide a new direction of cancer treatment.