[Construction and improvement of animal models with different positional osseous metastasis of prostate cancer in vivo].

OBJECTIVE: To provide an important tool for the study of diagnose and treatment of prostate cancer (PCa) osseous metastasis and change of bone stress force on prostate cancer (PCa) osseous metastasis and a platform, which is more congruous to clinical process, for prevention and cure of neoplastic bone metastases, and to carry out the construction and improvement of animal models of PCa with different positional osseous metastasis in vivo. METHODS: Different gradient concentrations of RM-1 cells were inoculated into the cavity of left femoral bone or lumbar vertebra of mice (C57BL/6) respectively. The change of mouse activity, tumor formation, tumor size and survival time were observed respectively. And the femur tissue and spinal tissue were obtained from the mice after death. The gray value of iconography were measured by imageological examination of femur tissue, and the final histopathological examination were taken to determine the tumor type in both femur and spinal tissue. RESULTS: The tumor growth could be touched at the puncture site in all the mice after inoculated for 7 days. There were no obvious differences in the time of tumorigenesis, the rate of tumor growth and tumor size among the mice in the same group (P>0.05). As the result, the construction femoral bone and lumbar vertebra metastatic models of PCa had been confirmed by iconography and pathology detection. At the same time, the survival time of the mice inoculated with low concentrations of PCa cells was obviously longer than that of high concentrations of PCa cells ( at least 2 weeks longer). CONCLUSION: The animal models with different positional osseous metastasis (limbs and axial skeleton) of PCa using the same PCa cells (RM-1) had been first constructed successfully in our study. At the same time, a high success rate of construction of PCa animal model with bone metastasis was obtained by femoral bone marrow cavity injection of PCa cells. The rate of tumor growth was rapid, animal survival time was appropriate, and the PCa animal model with bone metastasis can be stably reproduced by our method. These animal models can be used to explore the pathogenesis of different positional PCa bone metastasis and provide a new platform, which were more congruous to clinical process, for prevention and cure of neoplastic bone metastases.

Diallyl trisulphide-induced apoptosis in human melanoma cells involves downregulation of Bcl-2 and Bcl-xL expression and activation of caspases.

BACKGROUND: Although diallyl trisulphide (DATS) has been found to induce apoptosis in various tumour cells, its cytotoxicity in melanoma cells has not yet been defined and the molecular pathway by which DATS induces apoptosis is not well understood. OBJECTIVES: To determine growth inhibition of DATS in human melanoma cells (A375 and M14) by inducing apoptosis, and to investigate the mechanism underlying such effects. METHODS: Growth inhibition by DATS was estimated by the tetrazolium assay. Apoptosis induction in DATS-treated cells was assessed by staining with 4',6-diamidino-2-phenylindole (DAPI) and double staining with annexin V and propidium iodide. Expression of Bcl-2, Bax, Bcl-xL/Bcl-xS, cytochrome c release, activation of caspase-9 and poly(ADP-ribose) polymerase (PARP) were determined by western blotting. The activity of caspase-3 was measured using a colorimetric assay. RESULTS: DATS exerted its cytotoxic effect in a time-dependent and dose-dependent manner by inducing apoptosis in A375 and M14 cells. Expression of Bcl-2 and Bcl-xL was downregulated. Release of cytochrome c and activation of the downstream effectors caspase-3, caspase-9 and PARP were detected after DATS sensitization. CONCLUSIONS: DATS inhibits growth of melanoma cells by inducing apoptosis in association with downregulation of Bcl-2 and Bcl-xL and activation of caspases.