Figure 9. A dual role of HSPA5 in transcriptional mediation of ANXA1 and PSAT1 and its correlation with the clinicopathological features of OS. (A) PPI network of proteins GRP78 (HSPA5), Annexin A1 and PSAT1. (B) The gene regulation of ANXA1 and PSAT1 in stable HSPA5-expressing U-2 OS cells. (C) The expression of the indicated genes in HSPA5-siRNAs and HSPA5-rescued plasmid-transfected U-2 OS cells. (D) Stable HSPA5-expressing or the empty U-2 OS cells were subjected to immunoblotting analysis of PSAT1 and GRP78 levels. *P < 0.05 and **P < 0.01 compared to the control. (E, F) The expression levels of (E) Annexin A1 and PSAT1 and (F) molecules involved in AKT pathway and apoptotic pathway in HSPA5 siRNAs-transfected U-2 OS cells. (G) Expression of GRP78 and PCNA were detected by immunohistochemical staining in indicated adjacent normal tissues and tumors from OS patients. (H) Images of immunohistochemical staining for protein GRP78 in OS tissues of representative patients. (I) GRP78 expression increased progressively with aggressive progression of OS tissues with P-value less than 0.05. (J, K) IHC staining quantification of GRP78 and PCNA in the matched OS and adjacent normal tissues (n = 11 and 15, respectively). (L) The correlation of GRP78 and PCNA staining in OS tissues (n = 12). All data are shown with mean ± SD.*or #P < 0.05, **or ##P < 0.01 and ***or ###P < 0.001 in comparison with the indicated group; ns, no significant difference.