The Mechanism Of SKP2 Promoting Tumor Growth In Uveal Melanoma And Its Application As A Therapeutic Target

ObjectiveUveal Melanoma(UM)is the most common primary intraocular malignancy in adults worldwide.It is highly malignant and has the tendency to metastasize.However,the overall survival of UM patients has not increased significantly in recent years.SKP2 is considered an oncogene involved in various malignancies.SKP2 protein affects the cell cycle profoundly by specifically recognizing cell cycle regulators and mediating their ubiquitination and proteasomal degradation.SKP2 dysfunction is characteristic of many tumor cells.However,its role in uveal melanoma(UM)has not been elucidated.This study aimed to verify the function and mechanism of SKP2 in UM,and explore the feasibility of using small molecule drugs to target SKP2 to control UM.It was expected to provide new evidence and inspiration for deepening understanding of UM and targeted therapy to it.Content and methods1.The expressions of SKP2 in different UM cell lines compared with normal pigment cell was analyzed by RNA-seq,real-time PCR and western blot.2.Knocking down SKP2 in OM431 and MUM2 B cells and confirming its roles in cell proliferation and colony formation via CCK8 assay and colony formation assay,respectively.3.The sensitivity of cells to SKP2 inhibitor C1(SKPin C1)in vitro was evaluated by IC50 assay and colony formation assay,and the sensitivity of MUM2 B cells to SKPin C1 in vivo was estimated using the nude mouse-based xenograft model.4.Western blot and Immunoprecipitation assay were performed to detected the change of p27 and its ubiquitination level in UM cells treated with SKPin C1,respectively.Conclusion1.SKP2 was significantly highly expressed in UM cells compared with normal cells.2.SKP2 promoted the progression of UM and downregulation of SKP2 inhibited cell proliferation in UM cells.3.SKP2 inhibitor C1 that targets SKP2,essentially inhibiting the growth of UM cells both in vivo and in vitro.4.SKP2 inhibitor C1 decreased the degradation of p27 by blocking ubiquitylation of p27,resulting in p27 accumulation and cell cycle arrest in UM cells.Achievement1.We found the tumor-promoting effect of SKP2 gene in UM and SKP2 silencing could inhibit the growth of UM.2.We verified that the targeted interference of SKP2 in UM caused tumor growth inhibition both in vitro and in vivo,which was achieved by reducing ubiquitination degradation of p27.