Expression and role of HEPIS in breast cancer

Human embryo lung cellular protein interacting with severe acute respiratory syndrome-coronavirus nonstructural protein-10 (HEPIS) is expressed at varying levels in multiple organs and breast cancer cell lines. However, its expression and function in breast cancer cells has yet to be studied. Therefore, RNA in situ hybridization was used to detect the expression of HEPIS in breast cancer and cancer-adjacent normal breast tissue. HEPIS was expressed at lower levels in breast cancer compared with that in adjacent normal tissue. Subcellular localization of HEPIS was mainly found in the cytoplasm of HeLa cells. Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine cell proliferation assays were used to investigate the role of HEPIS in cancer cell proliferation. Ectopic expression of HEPIS in MCF-7 cells was found to significantly inhibit cell proliferation. In contrast, knockdown of HEPIS by RNA interference exhibited the opposite effect. Furthermore, a dual-luciferase reporter assay was performed and HEPIS overexpression specifically inhibited the activity of the NF-κB reporter gene. Results of the gene chip assay revealed that 2,231 genes were differentially expressed in HEPIS-overexpressing cells. Results of the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that these genes were enriched in the 'mitogen-activated protein kinase signaling pathway', 'JAK-STAT signaling pathway' and 'focal adhesion'. Reverse transcription-quantitative PCR was used to confirm the expression levels of the differentially expressed genes interleukin 2 receptor subunit α (IL2RA), interferon α and β receptor subunit 2 (IFNAR2) and IFα8 (IFNA8). In conclusion, the results of the present study indicated that HEPIS may function as a potential repressor of breast cancer.