Cell cycle was further detected with a FACScalibur flow cytometer (BD, USA)

Cell cycle was further detected with a FACScalibur flow cytometer (BD, USA). Cell migration assay Cells were seeded and transfected with control cDNA and Skp2 cDNA. MMP-9 in OS cells. In conclusion, our study demonstrated that Skp2 exhibited an oncogenic function in OS cells, suggesting that inhibition of Skp2 may be a novel approach for the treatment of OS. 0.05?vs Control. Discussion A wealth of evidence has demonstrated that Skp2 was critically involved in tumorigenesis including OS. It has been reported that Skp2 was highly expressed in OS tissue samples. Moreover, Skp2 expression was correlated with the relapse, metastasis, and survival rate in Rabbit polyclonal to CXCL10 OS.44 This finding implied that Skp2 could be a key oncoprotein in the occurrence and development of OS, and might be a prognostic indicator in OS.44 One study has shown that knockdown of GLI2, one key driver in Hedgehog pathway, enhanced cell cycle arrest via reduction of Skp2 in OS cells.45 Overexpression Arctiin of GLI2 promoted cell proliferation and accelerated cell cycle progression via overexpression of Skp2 in OS cells, indicating that Skp2 played a pivotal role in regulation of cell growth in OS cells.45 Another study found that Forkhead box M1 controlled the transcriptional network of genes essential for mitotic progression and genes encoding the SCF (Skp2-Cks1) ubiquitin ligase.46 Consistent Arctiin with the oncogenic role of Skp2 in OS cells, we found that overexpression of Skp2 enhanced cell growth and invasion, inhibited apoptosis and accelerated cell cycle progression in OS cells. Our study provided the direct evidence for oncogenic function of Skp2 in OS cells. Considering the oncogenic role of Skp2 in various cancer cells, it may be a good alternative to target Skp2 or to find Skp2 inhibitor for clinical cancer therapy. The MG132, a normal proteasome inhibitor, could inhibit cell proliferation and promote cell apoptosis though downregulating Skp2 in lymphoma Arctiin cells.47 However, the patients treated with proteasome inhibitor have many side effects.48 It is urgent to develop small molecular inhibitors without side effects to suppress Skp2. Cyclopamine, a specific inhibitor of SMO, slowed Arctiin the cell growth and promoted cell cycle arrest via reducing the expression of Skp2 and subsequent induction of p21 in OS cells.49 Moreover, inhibition of Notch pathway by its gamma secretase inhibitor prevents OS cell growth by cell cycle regulation via reduction of Skp2 expression.50 One study reports that CpdA (compound A) could block Skp2 binding to the SCF complex and suppress cell proliferation by inhibiting cell cycle and promoting apoptosis in myeloma cells.51 Moreover, CpdA is intensive to chemotherapeutic agents such as dexamethasone, doxorubicin, and melphalan, as well as proteasome inhibitor bortezomib in multiple myeloma.51 Interestingly, SMIP0004, one chemical compound, downregulates Skp2 in prostate cancer cells and accumulates protein p27.52 Recently, a new Skp2 inhibitor, compound 25, was found to restrict cancer stem cell traits and cancer progression.36 There is limitation to use chemical compounds to suppress Skp2 due to the inappropriate for human cancer. It is thought that natural agents may overcome these limitations and side effects. Recently, researchers found that curcumin, quercetin, lycopene, silibinin, epigallocatechin-3 gallate, could inhibit cell cycle progression and decrease the level of Skp2 in human cancers.53-56 Saurolactam, a natural compound isolated from the aerial portions of Saururus chinensis, was reported to inhibit proliferation, migration, and invasion via reduction of Skp2 expression in human OS cells.57 Additionally, 15,16-dihydrotanshinone I (DHTI), a lipophilic tanshinone extracted from Danshen root, was found to induce apoptosis and inhibit the cell proliferation, migration via suppression of Skp2 expression in OS cells.58 Recently, rottlerin was found to exert its antitumor activity through inhibition of Skp2 in human cancer cells.59,60 Matrine derivative YF-18 inhibited cell proliferation and migration via downregulation of Skp2 in lung cancer.61 It is Arctiin required to discover new Skp2 inhibitors for the treatment of OS. In conclusion, our work validated the oncogenic role of Skp2 in OS,.