Linc01638 Promotes Tumorigenesis in HER2+ Breast Cancer

Background: Long non-coding RNAs play crucial roles in various biological activities and diseases. The role of long intergenic non-coding RNA01638 (linc01638) in breast cancer, especially in HER2-positive breast cancer, remains largely unknown. Objective: To investigate the effect of linc01638 on tumorigenesis in HER2-positive breast cancer. Methods: We first used qRT-PCR to detect linc01638 expression in HER2-positive breast cancer cells and tissues. Then we analyzed the effects of linc01638 expression in HER2-positive breast cancer cells through cell apoptosis assay, cell proliferation assay, colony formation assay, and cell invasion assay. We conducted mouse xenograft model to further confirm the role of linc01638 in HER2-positive breast cancer. Moreover, we used Western blot and IHC analysis to access the effect of linc01638 on DNMTs, BRCA1 and PTEN expressions in transplanted tumors. Results: Linc01638 was found to be remarkably overexpressed in HER2-positive breast cancer cells and tissues. Suppression of linc01638 enhanced cell apoptosis, as well as inhibited the growth and invasiveness of HER2-positive breast cancer cells in vitro and tumor progression and metastasis in vivo. Furthermore, inhibition of linc01638 by shRNA attenuated expression of DNMT1, DNMT3a, and DNMT3b, and promoted expression of BRCA1 and PTEN in HER2-positive breast cancer cells and mouse xenograft models. Conclusion: Linc01638 might be a promising biomarker and therapeutic target for treatment of HER2-positive breast cancer.