Despite existing chemotherapy and surgical resection strategies, salivary gland adenocarcinoma(AdCa NOS) is one of the major causes of mortality among malignant salivary gland tumors. New therapeutic measure are needed to improve the outcome for patients with AdCa. Overexpression of urokinase-type plasminogen activator receptor/urokinase-type plasminogen activator(uPAR-uPA) has been implicated in progression and metastasis of oral cancer. RNA interference(RNAi) which has emerged as an effective method to target specific genes for silencing has provided new opportunities for cancer therapy. But there has been rarely reported using RNAi-uPAR/uPA transfection in salivary gland AdCa. The purpose of this study were to examine the specific inhibition of uPAR/uPA mRNA and protein expression by RNAi transfection of uPAR/uPA through RT-PCR and Immunoslot blot, and to study tumor cell proliferation activity, adhesion, invasion and migration of SGT cell line in vitro compared to the controls. In adhesion assay, cells transfected with RNAi-uPAR/uPA inhibited markedly adhesion to vitronectin compared to parental cells. Angiogenic assays revealed a significant decrease in the angiogenic potential of SGT cells downregulated by both uPAR and uPA. In migration assay, suppressing uPAR and uPA inhibited the capacity of the cells to migrate compared to parental cells. In invasion assay, cells transfected with RNAi-uPAR/uPA showed the maximum decrease in invasion when compared to all other treatment conditions. RNAi expressing plasmids efficiently downregulated mRNA and protein expression of uPAR and uPA. Cell cycle analysis showed that the simultaneous downregulation of uPAR and uPA caused the accumulation of cells in the sub-G0/G1 phase in SGT cells. Immunoslot blot analysis revealed that downregulation of uPAR and uPA caused the prominent activation of caspase 8. It suggested that the RNAi targeting of the uPAR/uPA system could have a therapeutic potentiality for malignant salivary gland tumors.

Recently, extensive research has been performed in the field of orthopedic medicine to develop cell-based therapies for the restoration of injured bone tissue. But there has been rarely reported about rehabilitaton of oral and maxillofacial bone defect using self-derived osteoblasts. Normal human osteoblast cell(NHost) was previously established into marrow-derived human mesenchymal stem cells for their capacity to proliferate and differentiate into osteoblasts under various culture conditions. The purpose of this study was to examine proliferation and differentiation of NHosts effected by growth factors with ALP activity and RT-PCR. After NHosts were cultured under basal and osteogenic medium at 37℃ and 5% CO2, they were analyzed by ALP activity and RT-PCR. BMP-2 under osteogenic medium decreased growth rate of NHosts compared to under osteogenic medium. BMP-2 under osteogenic medium induced osteoblastic differentiation in NHosts by increased ALP activity. The differentiating capacity of NHosts under osteogenic medium showed that NHosts expressed higher mRNA expression levels of OSX and OCN, while that of RUNX2 decreased after BMP-2 treatment. It suggested that NHosts having characteristics of osteoprecursor cells might be more advanced in their osteogenesis development by BMP-2, making NHosts an interesting biological tool for treatment of skeletal defects and diseases of oral and maxillofacial bone.