Study On Inactivation Of Osteosarcoma Cell Lines OS-9901 And SOSP-M3 In Vitro By Heat And Apoptotic Effect On Osteosarcoma Cell Lines OS-9901 Induced By Hyperthermia

Osteosarcoma (OSA) is one of the primary malignant bone tumors. OSA represents only 0.2% of all malignancies, with an incidence rate estimated as two to three new cases per million people per year. Most of the new cases occur in the second decade of life. The prognosis of traditional treatment of a classic high-grade OSA consists of surgical resection preceded and followed by multidrug systemic chemotherapy is worse, the 5-year disease-free survival rate was below 20%. Current neoadjuvant chemotherapy, hyperthermia and immunotherapy for OSA have a 65% to 70% 5- year disease-free survival rate.Following more and more appliance of heat treatment for malignant tumors, there are many studies on hyperthermia therapies for malignant bone tumors in vivo and in vitro. Because it is difficult to control the heat conditions of the tissues, there are many questions on reliability of heat method, inactivation effects of tumor cells, mechanism and prognosis.-7-Therefore, we explore the inactivation effects and mechanism of hyperthermia by heat the tumor cells in vitro.OBJECTIVE1. To study the optimum temperature and time for hyperthermia of two different metastatic OSA cell lines in vitro.2. To explore the apoptosis of the OSA cells induced by hyperthermia and supply the theory bases of treatment of OSA by middle-low temperature.METHODS1. After hyperthermia of two different metastatic osteosarcoma cell lines in vitro, assay SDH activity by MTT reduction assay and assay colony forming ability by colony forming of tumor stem cell.2. Using the electron microscope and microscope, we observed the alteration of structure, ultrastructure on OS-9901 cells with 43.5癈 Ih hyperthermia.3. Using the electrophoresis technology, we found the apoptosis death pattern of cells with 43.5癈 Ih hyperthermia.4. Using the immnohistochemical technology, we observed the expression of bcl-2 and p53 gene.RESULTS1. The heat sensitivity of two different osteosarcoma cell lines is similar.2. Following temperature heighting and time extending the SDH activity turns lower.3. Following temperature heighting and time extending the colony forming-8-ability turns lower.4. When OSA cells were treated with 43.5癈 for Ih, some apoptosis morphological features, such as volume reduction, chromatin condensation and apoptotic bodies can be found under light and electron microscope.5. The results of electrophoresis show a typical DNA "ladder" fragment which means the occurrence of apoptosis in hyperthermia treat group.6. The results of immunohistochemistry show the expression of p53 increased after heat the OS A cells with 43.5 癈 1 h.CONCLUSIONS1. 50癈 for 30 minutes seemed to be the optimum temperature and the time of osteogenic sarcoma thermotherapy.2. This study proved that 43.5癈 heat for Ih could induce apoptosis of OS-9901 cells. The results of the electron microscope and DNA electrophoresis also identified the finding.3.In this study we observe the hyperthermia can increase the p53 protein expression, which decide the phase of intracellular death program. This revealed the part theory of the apoptosis induced by heat.