Anti-tumor Effects Of Human Cord Blood Stem Cell Transplantation In BALB/C-nu/nu With Implantated Human Hepatocellula Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common solid cancers in china.With high malignancy and poor survival, it is the second major cause of cancer-related mortality. Over the years it became apparent that none of the available anti-cancer modalities or even combinations thereof could cure HCC, since relapse continued to be the single major obstacle in treatment of HCC especially of patients with advanced or resistant disease. Metastasis and recurrence are quite common , being as high as 50% in five years after curative resection even for small liver cancers in early stage. Then metastasis and recurrence have become the major obstacles to further improvement of clinical treatment efficacy of HCC.Considering lack of specific treatment modalities against HCC, and the high recurrence rate of surgical resection, a new available anti-cancer modality,immunotherapy, is becoming a very hopeful strategy. In the last two decades, various immunological strategies have been assessed to stimulate antitumor immunity in cancer patients, including vaccination with peptide- or tumor lysate-pulsed dendritic cells or cytokine-mediated immunotherapy. While to date these approaches have resulted in limited clinical benefits, defects in the immune system of the tumor-bearing host may be partially responsible for the low response rates from treatments designed to boost self (autologous) immunity to cancer.From the early 1970s, with the development of BMT, there is a growing perception that the graft-versus-malignancy reaction that follows allogeneic hematopoietic stem cell transplantation (HSCT) is arguably the most potent form of cancer immunotherapy currently in clinical use. For several reasons, an allogeneic-based immunotherapy for metastatic solid tumors could theoretically have efficacy superior toapproaches designed to enhance autologous immunity. First, a healthy donor immune system has yet to develop tolerance against tumor antigens and, once tolerance comes out, regular boosts of immune cells (i.e. DLI) with antitumor potential can subsequently be added. Secondly, donor T cells can be capable of recognizing a wide pool of antigens including minor histocompatibility antigens. In addition, some characteristics of epithelial tumor cells, such as their origin from normal tissues that are a target for GVHD and the high degree of MHC class I expression, may favor the generation of a GVT effect. In order to explore the potential of HSCT in the treatment of HCC,we established an human-mouse HSCT experimental animal model.In part one,we compared different methods for separating stem cells from umbilical cord blood,and find the 6%hydroxyethyl starch sedimentation is superior to other method. In part two, sublethal total body irradiation were performed to BALB/C-nu/nu mice to induce human to mouse microchimerism. 4 weeks after the injection of HSC,the microchimerism were oberserved by FCM.In part three,the cytotoxity of allogeneic stem cells to hepatocarcinoma cells were precisely analyzed by immunohistochemistry and FCM.PART ONE: The separation and purification of nucleated cells from umbilical cord bloodObjection: To find out an optimal method of separating hematopoietic stem cells (HSC) from umbilical cord blood,which will be the basis of further investigation.Methods: 10 cord blood(CB) were collected after spontaneous labor. 6 % hydroxyethyl starch were added to CB in a ratio of 1 part HES to 4 part CB , the other separating method is density gradient centrifugation (Ficoll-Hypaque).These two methods were compared and the efficacy of separation were examined by the means of FCM.umbilical cord blood;stem cells; 6 % HES sedimentation;density gradient centrifugation(Ficoll-Hypaque)human-mouse HSCT; hepatocellular caicinoma; Co⁶⁰ irradiation;engraftmentResults: 1.The percentage of CD45+ and CD 3 4 + cells is lower than that in the 4th weeks,so the human-mouse engraftment is a little unstable.2. the AFP concentration in different group is obviously different(48.55±7.47vs90.15±13.54vsl00.35±12.76/ig/L) 3.there were more serious tumor necrosis in the HSCTgroup and the tumor necrosis in the other groups is similar.No metastasis was foung in all the 3 groups 4. The tumor necrosis rate in the 3 groups are37.83± 10.69%, 16.17 + 3.50% and 13.71 + 2.58%,the HSCT group is more susceptible to tumor necrosis.5.Many human CD3+, CD8+ cells were observed in the tumor tissue of the HSCT group,while there were no human cells observed in the other 2 groups 6. Cytotoxity test:the spleen cells from the HSCT group had a much higher immune killing activity than that of the 2 other groups. Conclusion: Cord blood stem cells can induce immune killing to the SMMC — 7 7 2 1 hepatocellular caicinoma. HSCT can be a hopeful strategy inliver cancer treatment.