Effects Of SNRPD3 On Proliferation,metastasis And Molecular Mechanism Of Alternative Splicing In Triple Negative Breast Cancer

TNBC is a type of breast cancer with negative estrogen receptor,progesterone receptor,and human epidermal growth factor receptor-2,mainly occurring in young premenopausal women.The disease is aggressive with high distal metastasis rate and poor prognosis.SNRPD3 is a core component of the spliceosome and plays a key role in regulating the alternative splicing of RNA.However,little is known about the role of SNRPD3 in TNBC.In order to explore the effect of SNRPD3 on the development of TNBC and its related mechanisms,this study constructed MDA-MB-231 and BT549 cell models with overexpression/knockdown of SNRPD3,and verified the effect of SNRPD3 on the proliferation,clone formation and metastasis ability of TNBC cells through cell phenotype experiments.The results of cell proliferation assay(CCK-8)and colony formation assay showed that the overexpression of SNRPD3 significantly improved the proliferation ability and clone formation ability of TNBC cells,while the knockdown of SNRPD3 significantly reduced the proliferation ability and clone formation ability of TNBC cells.Cell scratch and Transwell experiments showed that overexpression of SNRPD3 promoted the migration of tumor cells in vitro,while knockdown of SNRPD3 significantly inhibited the migration of tumor cells.Then,RNA-seq results were analyzed by R language software,Kobas,Sangerbox and other websites,mainly including functional enrichment analysis of genes with differential expression and alternative splicing.Differential gene analysis showed that a variety of differentially expressed genes were enriched in tumor-related pathways,such as PI3K-Akt signaling pathway,Among the genes with variable splicing changes,exon skipping was the most common.PCR verification of some tumor-related SE genes showed that IKBKG had the most obvious splicing changes.Finally,the splicing region fragment of IKBKG was cloned and sequenced,and the protein structure was predicted.The results showed that the protein structure of IKBKG changed after SE.This study showed that SNRPD3 could promote the proliferation ability,clone formation ability and migration ability of TNBC cells in vitro,and SNRPD3 had a significant effect on the transcriptional expression of tumor-related pathway factors and alternative splicing,and revealed that IKBKG was a potential splicing target of SNRPD3.