DAL-1 attenuates epithelial to mesenchymal transition and metastasis by suppressing HSPA5 expression in non-small cell lung cancer

: Metastasis is the primary cause of death in lung cancer patients and EMT (epithelial-mesenchymal transition) promotes metastasis. Previous study revealed that DAL-1 (differentially expressed in adenocarcinoma of the lung) could attenuate EMT and metastasis in non-small cell lung cancer (NSCLC). Further study proved that HSPA5 (heat shock protein 5), which has a promoting effect on EMT, could bind to DAL-1. In this study, the mRNA and protein expression levels of target molecules were detected by RTq-PCR and western blot assays, the migration and invasion abilities were examined by Transwell migration and invasion assay, and the proliferation ability was measured by CCK-8 assay. We revealed that DAL-1 was downregulated while HSPA5 was upregulated in NSCLC and found the protein of DAL-1 and HSPA5 co-localized in the cytoplasm and nucleus. We demonstrated that DAL-1 can suppress the expression of HSPA5 on mRNA and protein levels, and decrease EMT, migration, invasion and proliferation abilities by down-regulating HSPA5. Furthermore, we discovered that DAL-1 plays a role in inhibiting PI3K/Akt/Mdm2 signaling pathway by suppressing HSPA5.