It is well-known that human epidermal growth factor receptor 2 (HER2) is critical for breast cancer (BC) development and progression. Several studies have revealed the role of the ubiquitin/proteasome system (UPS) in cancer. In this study, we investigated the expression level of Proteasome 26S subunit, non-ATPase 3 (PSMD3) in BC using BC cell lines, human BC tissue samples, Oncomine, and TCGA databases and studied the PSMD3-HER2 protein interaction. PSMD3 was upregulated in BC, particularly in the HER2+ subtype. PSMD3 immunostaining was detected in the cytoplasm and nucleus of BC tumor tissues. Strong interaction between PSMD3 and HER2 at the protein level was observed. Knockdown of PSMD3 significantly impaired the stability of HER2, inhibited BC cell proliferation and colony formation, and induced cell apoptosis. Ubiquitination process was strongly enhanced after knockdown of PSMD3 in association with decreased HER2 level. Accumulation and Localization of LAMP-1 in the cell membrane with decreased HER2 immunostaining was observed after knockdown of PSMD3. High expression level of PSMD3 was associated with HER2 expression (p < 0.001), tumor size (p < 0.001), and clinical stage (p = 0.036). High expression level of PSMD3 predicted a short overall survival (OS), particularly for HER2+. Overall, we provide a novel function for PSMD3 in stabilizing HER2 from degradation in HER2+ BC, which suggests that PSMD3 is a novel target for HER2+ BC.

Proteasome a highly sophisticated systems that alter protein structure and function. Proteasome 26S Subunit, Non-ATPase (PSMD) genes have been implicated in several types of malignancies. This is the first study to look at how proteasomal subunits are expressed in patients with bladder urothelial carcinoma (BLCA). BLCA was used to evaluate the predictive value of PSMD genes (PSMD1 to PSMD12) in relation to clinicopathological characteristics. PSMD genes’ expression patterns at the mRNA level were analyzed using a variety of bioinformatics methods, including gene expression profile integrative analysis (GEPIA), Oncomine, TCGA, and Gene expression Omnibus (GEO) databases. The GEPIA and TCGA dataset survival plot functions were used to assess the prognostic significance of PSMD genes. PSMD2, PSMD3, PSMD4, PSMD8, and PSMD11 genes were significantly overexpressed in BLCA compared with normal bladder tissues. PSMD2 and PSMD8 were significantly overexpressed in BLCA more than other types of cancer. High level of PSMD2 and PSMD8 predicted shorter overall (OS) and progression free survival (PFS) in BLCA patients. High level of PSMD2 was significantly associated with elder age (P < .001), female gender (P = .014), tumor grade (P < .001), and metastasis (P = .003). PSMD2 has been shown to be an independent predictor for OS in BLCA patients based on univariate and multivariate analysis (P < .001). Overall, according to this study, PSMD2 and PSMD8 could be served as a prognostic biomarker for BLCA patients.

Prostate cancer (PCa) is the second most common killer among men in Western countries. Targeting androgen receptor (AR) signaling by androgen deprivation therapy (ADT) is the current therapeutic regime for patients newly diagnosed with metastatic PCa. However, most patients relapse and become resistant to ADT, leading to metastatic castration-resistant PCa (CRPC) and eventually death. Several proposed mechanisms have been proposed for CRPC; however, the exact mechanism through which CRPC develops is still unclear. One possible pathway is that the AR remains active in CRPC cases. Therefore, understanding AR signaling networks as primary PCa changes into metastatic CRPC is key to developing future biomarkers and therapeutic strategies for PCa and CRPC. In the current review, we focused on three novel biomarkers (ZBTB46, SPDEF, and ETV6) that were demonstrated to play critical roles in CRPC progression, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) drug resistance, and the epithelial-to-mesenchymal transition (EMT) for patients treated with ADT or AR inhibition. In addition, we summarize how these potential biomarkers can be used in the clinic for diagnosis and as therapeutic targets of PCa.

StAR related lipid transfer domain containing 3 (STARD3) gene has been reported to be co-amplified with human epidermal growth factor receptor 2 (HER2) in breast carcinoma. STARD3 is necessary for cholesterol transfer and metabolism in tumor cells. The possible role played by STARD3 as a diagnostic and prognostic biomarker was investigated in breast cancer (BC). Data mining was performed using several bioinformatics websites to investigate the correlation of STARD3 with BC and its molecular subtypes, and conventional PCR was used to detect the STARD3 mRNA levels in a panel of BC cell lines. STARD3 was overexpressed in BC more than the other types of cancer. The results also showed that STARD3 expression was significantly associated with HER2(+) BC tumors and BC cell lines, and low STARD3 mRNA and protein expression levels were observed in estrogen receptor-positive (ER+) and triple-negative BC (TNBC) patients. Moreover, high SIARD3 expression levels predicted worse overall survival (OS), relapse-free survival (RFS) and disease metastasis-free survival (DMFS) in BC, and HER2(+) BC. Notably, low expression of STARD3 was associated with poor OS in ER+ BC. Our findings suggest that STARD3 may have strong diagnostic and prognostic value for HER2(+) breast carcinoma.