FOSL1 Promotes Tumorigenesis In OS By Activating ERK/AP-1 Signaling And The Function Of LncRNA-UFC1 In OS Progression

Osteosarcoma(OS)is a common primary malignant tumor.It has a high incidence and seriously threatens our health.The proliferation rate of osteosarcoma is very fast,which makes the prognosis of osteosarcoma poor and the survival rate within 5 years is low.Therefore,the molecular mechanism of rapid proliferation of osteosarcoma play a very important role.The mechanism of osteosarcoma is very important.However,there is a lack of research on the specific pathogenesis of osteosarcoma caused by FOSL1,especially the way that FOSL1 can help osteosarcoma cell proliferation is unclear.It is very important to study the mechanism of osteosarcoma.At the same time,the pathogenesis of osteosarcoma must be the result of the interaction of multiple genes.Relevant studies have proved that lncRNA-UFC1 plays an important role in tumor and inflammation and can regulate the development of related diseases.However,whether lncRNA-UFC1 also plays a role in osteosarcoma,and how it plays a role has not been reported in the literature.Therefore,in-depth studies on the pathogenesis of osteosarcoma and the regulation mechanism of relevant genes in osteosarcoma cells are necessary for the clinical treatment of osteosarcoma.In the first part of this study,the main purpose was to explore the mechanism of the effect of FOSL1 on osteosarcoma cells,and to explore the effect of FOSL1-mediated ERK/AP-1 signaling pathway on the proliferation,invasion and migration of osteosarcoma cells.We first quantitatively analyze FOSL1 related molecules and ERK/ AP-1 related molecules in fresh osteosarcoma tissues and corresponding para cancerous tissues at the expression and transcription levels by qRT-PCR and Western-blot,meanwhile analyze the expression of FOSL1 in osteosarcoma tissues by immunohistochemistry.Furthermore,we examined the effects of si-FOSL1 on the transcription and protein expression levels of C-JUN,C-FOS,ERK1/2,p-ERK1/2,p38 MAPK and p-p38 MAPK.Next,the inhibitory effect of si-FOSL1 on the proliferation capacity of osteosarcoma cells was observed by CCK-8(Cell counting kit-8)experiments,and tumor formation ability of si-FOSL1 cell line inoculated in immunodeficient mice was observed by CB17 severe combined immunodeficient mice.After that,Flow cytometry detected the changes in the cell cycle of si-FOSL1.Finally,the influence of FOSL1 on the invasion ability of osteosarcoma cells was detected by Transwell cell invasion test,and the influence of FOSL1 on the migration ability of osteosarcoma cells was detected by cell scratch test.The results showed that: 1.In osteosarcoma tissues,the expressions of FOSL1 and ERK/ ap-1 related molecules were significantly up-regulated.2.PCR and Western-blot results showed that si-FOSL1 could reduce the expression levels of C-JUN,C-FOS,p-ERK1/2 and p-p38 MAPK.3.The expression levels of p-ERK1/2 and p-p38 MAPK in the overexpressed FOSL1 group were decreased after the addition of ERK/AP-1 inhibitors.4.Flow cytometry and CCK-8 experiments confirmed that FOSL1 could affect the proliferation of osteosarcoma cells by affecting cell cycle.5.The tumorigenic ability of the si-FOSL1 group was significantly decreased in vivo.6.Transwell cell invasion assay showed that si-FOSL1 group could significantly inhibit the invasion ability of osteosarcoma cells,which increased in the overexpression of FOSL1 group.7.Cell scratch assay showed that si-FOSL1 group could significantly inhibit the migration ability of osteosarcoma cells,which increased in the overexpression group.It is concluded that FOSL1 affects the ability of osteosarcoma cells to proliferate,invade and migrate through ERK/ ap-1signaling pathway,and may provide a new target for the treatment of osteosarcoma.In the second part of this study,we conducted a preliminary study on the regulation of lncRNA-UFC1 on osteosarcoma.First,the expression levels of lncRNA-UFC1 in osteosarcoma and adjacent tissues were detected by qRT-PCR.The expression levels of lncRNA-UFC1 in MG-63,U20 S and SaOs-2 cell lines were analyzed by qRT-PCR to screen cell lines for subsequent experiments.Next,we used MTT test,clonal formation test and in situ hybridization test to observe the proliferation of osteosarcoma cells after overexpression and knockdown of lncRNA-UFC1.Finally,we inject SaOs2 cells with overexpression and knockdown of lncRNA-UFC1 into mice to observe their proliferation capacity of osteosarcoma in vivo.The results show: 1.qRT-PCR results showed that lncRNA-UFC1 expression was significantly increased in osteosarcoma tissues.2.MTT assay,clonal formation assay and in situ hybridization assay all confirmed that lncRNA-UFC1 could promote the proliferation of osteosarcoma cells in vitro.3.Animal experiments furtherconfirmed that lncRNA-UFC1 can also promote the proliferation of osteosarcoma cells in vivo.It was concluded that lncRNA-UFC1 could promote the proliferation of osteosarcoma cells and play an important role in the regulation of osteosarcoma.