Abstract: Objective To investigate the expression of inhibitor of DNA differentiation/DNA binding 1 (Id1) and Id3 in
endometrial carcinoma and explore their roles in regulating the proliferation, invasion, migration and adhesion of endometrial
carcinoma cells in vitro. Methods Id1 and Id3 expression in 4 fresh endometrial cancer tissue specimens and matched adjacent
tissues were detected using Western blotting. Two endometrial cancer cell lines, HEC-1-B and RL-952, were both divided into 4
groups, namely the untreated group, blank virus group, promoter group and Id1/Id3 double-knockdown group, and their
expressions of MMP2, CXCR4 and P21 were detected by qRT-PCR and Western blotting. The proliferation, invasion, migration
and adhesion of the cells were evaluated with MTT, Transwell, wound-healing, and adhesion assays. Results Endometrial
carcinoma tissues showed significantly higher Id1 and Id3 expression than the adjacent tissues (P<0.05). In the two endometrial
carcinoma cell lines, Id1/Id3 double-knockdown significantly decreased MMP2 and CXCR4 expression and increased P21
expression at both mRNA and protein levels (P<0.05), and resulted in suppressed cell proliferation, invasion, migration and
adhesion. Conclusions Id1 and Id3 expressions are up-regulated in endometrial carcinoma to promote the proliferation,
invasion, migration and adhesion of the tumor cells by increasing MMP2 and CXCR4 expression and reducing P21 expression.
Therapies targeting Id1/Id3 can be a novel strategy for treatment of endometrial carcinoma.