Immunohistochemical localization of steroid receptor coactivators in chondrosarcoma: an in vivo tissue microarray study

Imbalanced expression pattern of steroid receptor coactivator-1 and -3 in liver cancer compared with normal liver: An immunohistochemical study with tissue microarray

Steroids affect normal and pathological functions of the liver through receptors, which require coactivators for their transcriptional activation. Steroid receptor coactivator (SRC)-1 and SRC-3 have been demonstrated to be regulated in numerous cancers; however, their expression profiles in liver cancer including hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC) remain unclear. Using tissue microarray immunohistochemistry, normal liver tissue and HCC tissue exhibited immunoreactivity of SRC-1, which were predominantly localized within extranuclear components; in CCC, they were detected within the cell nuclei; SRC-3 was also detected in the cell nuclei. Furthermore, no altered expression of SRC-1 and SRC-3 was observed in liver cancer compared with normal liver tissue; however, in CCC, the expression of SRC-3 was significantly increased compared with that detected in HCC. Importantly, although expression of SRC-1 and SRC-3 did not reveal any significant differences (30 vs. 40%) in normal liver tissue, HCC and CCC expression of SRC-1 was significantly decreased compared with that of SRC-3 (9.3 vs. 36%, and 6.7 vs. 67.7% for HCC and CCC, respectively). Further comparative analysis revealed that this discrepancy was detected in males with liver cancer, across all ages of HCC cases, younger CCC cases and all stages of liver cancer. The results suggested the presence of an imbalanced expression pattern of SRC-1 and SRC-3 from normal liver tissue to liver cancer (decreased SRC-1 and increased SRC-3), which may affect hepatic function and therefore promote liver carcinogenesis.

Steroid Receptor Coactivator-3 (SRC-3/AIB1) as a Novel Therapeutic Target in Triple Negative Breast Cancer and Its Inhibition with a Phospho-Bufalin Prodrug

Triple negative breast cancer (TNBC) has the poorest prognosis of all types of breast cancer and currently lacks efficient targeted therapy. Chemotherapy is the traditional standard-of-care for TNBC, but is frequently accompanied by severe side effects. Despite the fact that high expression of steroid receptor coactivator 3 (SRC-3) is correlated with poor survival in estrogen receptor positive breast cancer patients, its role in TNBC has not been extensively investigated. Here, we show that high expression of SRC-3 correlates with both poor overall survival and post progression survival in TNBC patients, suggesting that SRC-3 can serve as a prognostic marker for TNBC. Furthermore, we demonstrated that bufalin, a SRC-3 small molecule inhibitor, when introduced even at nM concentrations, can significantly reduce TNBC cell viability and motility. However, because bufalin has minimal water solubility, its in vivo application is limited. Therefore, we developed a water soluble prodrug, 3-phospho-bufalin, to facilitate its in vivo administration. In addition, we demonstrated that 3-phospho-bufalin can effectively inhibit tumor growth in an orthotopic TNBC mouse model, suggesting its potential application as a targeted therapy for TNBC treatment.