| Background Cutaneous squamous cell cancer (cSCC) is a common human skin cancer, accounting for about 20% of all non-melanocytic skin cancer. SCC most occurs in elderly patients and more often occurs on head and face, vulva and external genitalia. Traditional treatments including surgery, laser, freezing or radiotherapy can remove or destroy tumor tissue directly, but there are a lot of disadvantages for example organizational structure destructive, recurrence, difficulty in treating again. Due to the weak immunogenicity of SCC, host functional defects in immunity or poor cannot induce effective anti-tumor immune response. This is main reason of recurrence and metastasis for SCC. Therefore, it is necessary to look for the ideal tumor therapy that cloud not only kill tumor cells but also stimulate the body’s anti-tumor immune response by enhance the immunogenicity of the tumor cells. Photodynamic therapy(PDT) involves the accumulation of photosensitizer in diseased tissues followed by illumination of disease site with light of an appropriate wavelength to induce photochemical reactions that result in tissue destruction. PDT can not only kill the tumor cells directly and damage the vasculature of the tumor, but antigens (such as HSP70, HMGB1) released from tumor tissues after PDT can induce anti-tumor immune response. Previous studies have shown that DC, CD4+T cells and CD8+T cells increased significantly and TNF-a,IL-1β and IL-6 upregulated in the topical tissue after PDT. Dendritic cell (DC),a kind of antigen-presenting cell is a bridge between innate and adaptive immune response and plays an important role in the immune system. Under normal circumstances, DC is immature which performs a strong ability of antigen capture. After stimulated by tumor antigen, DC was induced to mature whose capacity of antigen presenting significantly enhanced. Mature DC can present tumor antigen peptide complex to T cells to initiate host immune response against tumor. Research shows that, DC impacted by tumor antigen peptide in vitro, it will be induced to DC vaccine that can anti-tumor. There are also reports that DC vaccine which produced from tumor cell lysates co cultured with DC can induce specific cytotoxic T cell responses.Objective To Study the maturity of DC produce from PECA cell lysate treated by ALA-PDT co-cultured with primary cultured DC. And to further explore the efficacy and mechanism of the prepared PDT-DC vaccine for prevention of skin squamous cell carcinoma.Method (1) Preparation of PDT-DC vaccine for cSCC. The primary cultured DC co cultured with the cell lysate of PECA produced by ALA-PDT. Then the DC was observed under inverted microscope and transmission electron microscope. The morphology of DC was examined by flow cytometry for CD80,CD86 and MHC-Ⅱ.(2) Observation of the effect of PDT-DC vaccine for prevention of cSCC.50 mice, which were divided into 5 groups. PDT-DC vaccine, PDT-PECA, F/T-DC and RPMI 1640 were injected subcutaneously (s.c.) into the left flank of SKH-1 hairless mice, respectively. Immunization was done three times with a 7-day interval. Mice were then rechallenged with live untreated PECA cells in the other (right) flank 7 days after the third immunization. The rate of tumor formation,the volume of the tumor and the weight of mouse were calculated everyday. (3)Studies of mechanism of PDT-DC vaccine for prevention of cSCC.Seven days after PECA cells injection, immunohistochemistry, flow cytometry and ELISA were done for the mechanism of PDT-DC vaccine for prevention of cSCC.Result (1)DC can be induced to mature when primary cultured DC co cultured with the cell lysates of PECA produced by ALA-PDT. Meanwhile,CD80,CD86 and MHC-Ⅱ which are on the surface of DC upregulated.(2) The rate of tumor formation of PDT-DC vaccine group, PDT-PECA group, F/T-DC group and control group was 0,50%,90% and 100%. The volume of formation tumor and the weight of the mouse increased with time.(3) The results of immunohistochemistry showed that:topical CD4+T and CD8+T cells were all positive in PDT-DC vaccine group, while CD4+T and CD8+T cells were negative in control groups. And Treg cells showed no obvious positive in all groups. The percentage of CD4+T and CD8+T cells of the spleen cells in PDT-DC vaccine group are higher than that of control groups, and the proportion of Treg cells was lower than that of control groups. The content of IFN-y and IL-12 in the peripheral blood were higher than that of control groups, while IL-10 was lower.Conclusion PDT-DC vaccine produced from primary cultured DC co cultured with cell lysate of PECA treated by ALA-PDT can prevent skin squamous cell carcinoma. |
PDF Full Text Request