Experimental Study On Antitumor Effect By Intratumoral Injection Of Xenogeneic Antigen In Mice Bearing S180 Sarcoma

Cancer as a serious chronic disease affects human health, the morbidity and mortality increases year by year. In the development of China, the growing incidence and treatment costs, has restricted the stumbling block to social progress and development. Cancer treatment through traditional surgery, chemotherapy, radiotherapy, molecular targeted therapy to the current seems to understand human tumors is still very limited. Although cancer has been recognized as a systemic disease, oncologists are trying to systematically integrated treatment, but the achievement is not satisfactory.Clearly, not enough to eliminate tumor by the traditional treatment, then can we find new ways from the biological behavior of tumors? No one knows the answer, but some oncologists are trying to interfere with tumor immune to find the answer, a new immune therapy has began to be used in cancer patient. Immunotherapy become the focus of attention of tumor clinical. The purpose of tumor immunotherapy is to stimulate or mobilize the immune system, regularing the tumor microenvironment to enhance anti-tumor immunity. Immunotherapy have tured into the fourth treatement methods following the surgery, chemotherapy and radiotherapy for cancer treatment. Immunostimulants are a class of broad biological activity and antitumor activity of biological agents, both in a large class of naturally occurring biological substances, but also the host and the tumor can change the balance of the body's ways and means, are widely used anti-cancer therapy. Although the mechanism are various, but no more than two major aspects:nhibition tumor by interfering with cell growth, transformation, or transfer directly and enhance specific immune by activating effector cells and secreting cytokines. Okamoto H first use streptococcus to prepare OK-432. The agent, not only directly kill tumor cells, can also enhance the body's anti-tumor immune function, such as:activated NK cells, macrophages and complement system, has been used in clinical anti-cancer therapy. More research showed that the number of regulatory T cell (Treg) increase in patients with solid tumors and blood malignancies, and the number of Treg with tumor progression and prognosis, the survival rate was negative correlate. Early results show that the Centre take inactivated Streptococcus sequential intratumoral injection to enhance the effect of immune cells in mice, then tumor MHC-Ⅰantigen increases, and the number of tumor local regulatory T cells decreases,which can be effective in improving local tumor immune status. Sequential therapy is currently no clear definition, the sequential drug treatment usually refers to the continuous administration of drug to achieve a stable blood concentration of anti-tumor agents or suspended after the switch to oral medication, in order to maintain effective drug concentrations in plasma. Use of sequential therapy can be shortened hospital stay and reduce the cost of treatment, preventing the side effects caused by long-term intravenous infusion,so sequential therapy is worthy of a clinical treatment. Preparations for the long-term application of immunopotentiator, we designed for use a heteroantigen to explore the anti-tumor effect with different patterns of intratumoral administration of mice bearing S180 saroma, and the tolerance of injecting inactivated streptococcus by intratumoral way, and the pathological changes of vital organs.We focus on analyzing the expression of Bcl-2 protein and Bax protein after intratumoral injection in tissue of S180 saroma.Purpose ·To study the antitumor effect of the inactivated streptococcus intratumoral injection on mice bearing S180 saroma and the expression of Bcl-2 and Bax protein in tumor tissue, and the long-term safety of using the inactivated streptococcus. adjusting the cell concentration of 1×107 cells/ml. Use 0.1ml cell suspension inoculated in 40 mice of 4-6 weeks old subcutaneously. Tumor formation rate close to 100%.2. Animal groups After the modeling, the first 8 days, according to the principle of uniformity of size selected 30 mice were divided into three groups of 10 each:A, continuous intratumoral injection of inactivated Streptococcus group; B, sequential intratumoral injection of inactivated Streptococcus group; C, continuous intratumoral injection of normal saline control group.3. Intratumoral injection of drugs and placebo In accordance with the groups began:Group A of consecutive daily intratumoral injection of mice with the concentration of inactivated Streptococcus 1mg/ml 0.1ml/only; Group B, tumors in mice injected for 5 days to eliminate the concentration of lmg/ml inactivated Streptococcus 0.1ml/only, and then rest 2 days; Group C, continuous intratumoral injection of saline 0.1ml/only. All intratumoral injection of sterile operation are strictly adhered to, to multi-point injection.4. Observation and measurement of experimental data Weekly measurement of tumor size after injection, then we compute tumor size. Tumor volume by the formula: diameter×width2/2.5. Immunohistochemical measurement of tumor tissue Bcl-2, Bax protein expression6. Digital picture information Using Image-pro plus software processing immunohistochemical picture7. Statistical analysis Using the SPSS 13.0 statistical software, choose the appropriate statistical analysis of data.8. The safety of drugs Collecting the liver and kidney specimens, then observing histological changes by H.E staining.Results Compared with the control group, continuous treatment group and the sequential treatment group had significant anti-tumor effect (P<0.05), but there was no significantly difference between the continuous group and the sequential group (P> 0.05). Growth curves of mice in each group showed that the median survival time of three groups of mice after treatment was 38.0 days,37.0 days,34.0 days. With the control group, the expression of Bcl-2 protein reduced significantly on the group of intratumoral injection of inactivated Streptococcus, and the expression of Bax protein increased significantly (P<0.05). There was no significantly difference between the continuous group and the sequential group on the expression of Bcl-2 and Bax protein (P>0.05). As a xenoantigen, inactivated Streptococcus does not increase immune damage of liver and kidney in tumor-bearing mice.Conclusion Intratumoral injection of inactivated Streptococcus continuous method has significantly inhibit the S180 tumor growth in mice, significantly increased the median survival time of mice, and the sequential injection can achieve the same effect with a continuous injection. The antitumor effect of inactivated Streptococcus may be through the promotion of apoptosis of tumor cells by regulating the expression of Bcl-2 protein and Bax protein. Continuous medication don't damage to the liver and kidneys, using good security.