LncRNA Expression Profiles in Canine Mammary Tumors Identify lnc34977 as a Promoter of Proliferation, Migration and Invasion of Canine Mammary Tumor Cells

Canine mammary tumor (CMT) is the most common tumor in canines after skin tumors. Long noncoding RNAs (lncRNAs) have crucial roles in human breast tumor initiation and progression, but the role of lncRNAs in canine mammary tumors is unclear. We analyzed the expression profiles of canine mammary tumors and their adjacent non-neoplastic tissue to explore abnormally expressed lncRNAs. LncRNA expression was detected by qRT-PCR. After overexpression of lnc40589 and knockdown of lnc34977 in CMT cells, CCK-8, colony formation, wound healing and Transwell assays were used to assess the proliferation, migration and invasive ability of canine mammary tumor cells. We also established a mammary tumor-bearing nude mouse model. GO analysis and KEGG pathway analysis demonstrated that the differentially expressed lncRNAs were closely related to the mammary tumor. lnc40589 was significantly upregulated and lnc34977 was significantly downregulated in CMTs. In addition, lnc40589 inhibits cell proliferation, migration and invasion, while lnc34977 promotes cell proliferation, migration and invasion. In addition, lnc34977 promotes the development of mammary tumors in animals. Taken together, our study results reveal the lncRNA expression profiles in CMTs and indicate that lnc34977 promotes the development of CMT both in cell culture and in vivo.