A high AR:ERα or PDEF:ERα ratio predicts a sub-optimal response to tamoxifen therapy in ERα-positive breast cancer.

PURPOSE: Approximately 30% oestrogen receptor alpha (ERα)-positive breast cancer (BC) patients exhibit intrinsic or recurrent resistance to adjuvant endocrine therapy with tamoxifen. The androgen receptor (AR) is expressed in about 90% of ERα-positive patients, with particularly high expression in tamoxifen-resistant tumours. Prostate-derived Ets factor (PDEF), which is a co-regulator of AR, plays a role in tamoxifen resistance in ERα-positive BC. The purpose of this research was to analyse the potential roles of AR, PDEF and ERα levels in the response to tamoxifen resistance in ERα-positive BC. METHODS: The nuclear AR:ERα and PDEF:ERα ratios were examined immunohistochemically in a cohort of 225 ERα-positive pre-menopausal BC patients who had received adjuvant tamoxifen therapy. RESULTS: For both AR:ERα and PDEF:ERα ratios, the optimal cutoff value was 2.0. Patients receiving adjuvant tamoxifen treatment who had a high AR:ERα (≥ 2.0) (HR = 3.90) or PDEF:ERα ratio (≥ 2.0) (HR = 2.77) had a beyond twofold increased risk of failure. Both the AR:ERα ratio (P = 0.001) and PDEF:ERα ratio (P = 0.002) were independently associated with the risk of tamoxifen treatment failure. Furthermore, both a high ratio of AR:ERα (≥ 2.0) and PDEF:ERα (≥ 2.0) were associated with shorter disease-free survival (DFS) and shorter disease-specific survival (DSS). In addition, both the AR:ERα ratio and PDEF:ERα ratio were independent predictors of DFS (both P < 0.0001) and DSS (P = 0.001 and P < 0.0001, respectively). CONCLUSIONS: AR:ERα and PDEF:ERα ratios are independent predictors of the response to conventional ERα-directed tamoxifen endocrine therapy.

ß-Catenin nuclear localization positively feeds back on EGF/EGFR-attenuated AJAP1 expression in breast cancer.

BACKGROUND: Adherent junction associated protein 1 (AJAP1), a typical molecule of adherent junctions, has been found to be a tumor suppressor in many cancer types. Aberrant activation of ß-catenin has been demonstrated to be associated with malignant biological properties of tumors including breast cancer. This study aimed to investigate the function and mechanism of AJAP1-mediated ß-catenin activity of breast cancer lines in vitro and in breast cancer patients. METHODS: AJAP1 and ß-catenin expressions in breast cancer tissues and cell lines were detected by immunohistochemistry, western blotting and qRT-PCR. The EGF/EGFR axis-mediated AJAP1 attenuated ß-catenin nuclear location was measured by western blotting, immunofluorescence assay, co-immunoprecipitation, luciferase assay and ubiquitination assays. Furthermore, the function of AJAP1 and ß-catenin regulated breast cancer progression was explored both in vivo and in vitro. RESULTS: It was found that AJAP1 had a high negative correlation with ß-catenin nuclear expression and was a novel tumor suppressor in breast cancer. AJAP1 loss can mediate ß-catenin accumulated in cytoplasm and then transferred it to the nucleus, activating ß-catenin transcriptional activity and downstream genes. Additionally, ß-catenin can reverse the invasion, proliferation ability and tumorigenicity of the depletion of AJAP1 caused both in vivo and in vitro. Besides, EGF/EGFR also involved in the process of AJAP1-depiction induced ß-catenin transactivation to the nucleus. More importantly, EGFR depletion/AJAP1 knocked down promoted the progression of breast cancer by regulating the activity of ß-catenin nuclear transactivation. CONCLUSION: This study demonstrated that AJAP1 acted as a putative tumor suppressor while ß-catenin nuclear localization positively fed back on EGF/EGFR-attenuated AJAP1 expression in breast cancer, which might be beneficial to develop new therapeutic targets for decreasing nuclear ß-catenin-mediated malignancy in breast cancer.

Prognostic role of Amphiregulin and the correlation with androgen receptor in invasive breast cancer.

BACKGROUND: In androgen-sensitive prostate cancer, androgenic stimulation induces the synthesis of amphiregulin (AREG). Research is lacking on the role of AREG in invasive breast cancer and the co-expression with androgen receptor (AR) status. MATERIALS AND METHODS: The present study investigated the prognostic role of AREG in invasive breast cancer cases (N = 298) and the co-expression with the AR status as analysed by immunohistochemistry (IHC). RESULTS: The samples were divided into groups according to AREG expression levels: low/no expression (AREGlow/no) and high expression (AREGhigh). As shown by cytoplasmic immunostaining, 46.0% (137/298) of invasive breast cancers were AREGhigh, and 54.0% (161/298) of cases were AREGlow/no. Co-expression of the AR and AREG accounted for 62.4% (186/298) of cases. A Kaplan-Meier analysis revealed that AREGhigh and AR+/AREGhigh decreased patients' overall survival (OS) (P = 0.002 and P = 0.006, respectively) and disease-free survival (DFS) (P < 0.001 and P < 0.001, respectively). In Cox models, AR+/AREGhigh remained an independent prognostic indicator of OS and DFS in invasive breast cancer (hazard ratio [HR], 0.591, 95% confidence interval [CI], 0.407-0.859, P = 0.006; HR, 0.449, 95% CI, 0.236-0.853, P = 0.014, respectively). AREGhigh remained an independent prognostic indicator of OS and DFS in estrogen receptor (ER)-negative tumours (P < 0.05). CONCLUSIONS: This study suggested that AREG and the AR were co-expressed in invasive breast cancer. Thus, AREG and the AR may be valuable prognostic biomarkers in invasive breast cancer and promising therapeutic targets, especially in ER-negative breast cancer.

TGF-ß1 stimulates epithelial-mesenchymal transition and cancer-associated myoepithelial cell during the progression from in situ to invasive breast cancer.

BACKGROUND: The progression of ductal carcinoma in situ (DCIS) into invasive ductal carcinoma (IDC) is prevented by normal breast myoepithelial cells. Studies have suggested that EMT-associated genes were enriched in IDC in contrast to DCIS. This paper explored the relationship and potential mechanism between myoepithelial cells and EMT-associated genes in facilitating the transformation from DCIS to breast cancer. METHODS: EMT markers and myoepithelial phenotypic markers in IDC, DCIS, and healthy breast tissue were characterized using immunohistochemical assay. Both in vivo and in vitro models were created to mimic the various cell-cell interactions in the development of invasive breast cancer. RESULTS: We found that EMT markers were more abundant in invasive carcinomas than DCIS and adjacent normal breast tissue. Meanwhile, TGF-ß1 regulated the morphology of MCF-7 (epithelial cells substitute) migration and EMT markers during the transformation from DCIS to invasive breast cancer. Additionally, TGF-ß1 also regulated invasion, migration and cytokines secretion of MDA-MB-231 (myoepithelial cells substitute) and epithelial cells when co-cultured with MCF-7 both in vitro and in vivo. CONCLUSIONS: In conclusion, these findings demonstrated that both EMT phenotypes and cancer-associated myoepithelial cells may have an impact on the development of invasive breast cancer.

AR-PDEF pathway promotes tumour proliferation and upregulates MYC-mediated gene transcription by promoting MAD1 degradation in ER-negative breast cancer.

BACKGROUND: Androgen receptor (AR) is expressed in 60%~ 70% oestrogen receptor (ER)-negative breast cancer (BC) cases and promotes the growth of this cancer subtype. Expression of prostate-derived Ets factor (PDEF), a transcription factor, is highly restricted to epithelial cells in hormone-regulated tissues. MYC and its negative regulator MAD1 play an important role in BC progression. Previously, we found that PDEF expression is strongly correlated with AR expression. However, the relationship between AR and PDEF and the function of PDEF in ER-negative BC proliferation are unclear. METHODS: AR and PDEF expression in ER-negative BC tissues and cell lines was determined by performing immunohistochemistry or western blotting. Protein expression levels and location were analysed by performing western blotting, RT-qPCR and immunofluorescence staining. Co-immunoprecipitation and chromatin immunoprecipitation assays were performed to validate the regulation of AR-PDEF-MAD1-MYC axis. Moreover, the effect of AR and PDEF on BC progression was investigated both in vitro and in vivo. RESULTS: We found that PDEF was overexpressed in ER-negative BC tissues and cell lines and appeared to function as an oncogene. PDEF expression levels were strongly correlated with AR expression in ER-negative BC, and PDEF transcription was positively regulated by AR. PDEF upregulated MYC-mediated gene transcription by promoting MAD1 degradation in ER-negative BC. Finally, we found that compared with the inhibition of AR expression alone, simultaneous inhibition of AR and PDEF expression further suppressed tumour proliferation both in vitro and in vivo. CONCLUSIONS: Our data highlight the role of the AR-PDEF-MAD1-MYC axis in BC progression and suggest that PDEF can be used as a new clinical therapeutic target for treating ER-negative BC.

Clinical significance of PDEF factor expression and its relation to androgen receptor in ER- breast cancer.

AIMS: The mechanism of androgen receptor (AR) promoting tumour growth in oestrogen receptor-negative (ER- ) breast cancer (BC) is undetermined. Prostate-derived ETS factor (PDEF) is highly restricted to the hormone-regulated tissues of epithelial cells, such as those in the prostate, breast and other tissues. It has been demonstrated that PDEF expression is associated with AR in prostate cancer. In this research, we aimed to investigate the relationship between PDEF and AR in ER- BC. METHODS AND RESULTS: We immunohistochemically evaluated the correlation between PDEF and AR expression in 246 cases of ER- invasive BC, and investigated their relationship in ER- BC cell lines. The expression of PDEF was associated with the positive expression of AR (P < 0.001) and a worse survival rate (P = 0.006). PDEF+ tumours were significantly more often AR+ (P < 0.001). AR and PDEF were more often co-expressed and the series of AR+ PDEF+ (126 of 246, 51.2%) had a poor survival rate (P = 0.046). In Cox models, PDEF expression (P = 0.028) was an independent predictor for overall survival (OS). At the cellular protein and mRNA levels, our experiments also showed a statistically significant positive correlation between PDEF and AR, and that PDEF may be regulated by AR. CONCLUSIONS: PDEF is associated with markers of bad prognosis, supporting its role as a growth promoter in ER- BC. Our findings also provide evidence that PDEF is strongly correlated with AR expression in ER- breast cancer; it may be a downstream target gene of AR and a potential prognostic factor in ER- BC.

Androgen receptor and heat shock protein 27 co-regulate the malignant potential of molecular apocrine breast cancer.

BACKGROUND: The most striking feature of molecular apocrine breast cancer (MABC) is the expression of androgen receptor (AR). We report here the mechanism of the AR in regulating the behavior of MABC. METHODS: The MABC cell line, MDA-MB-453, and the nonMABC cell line, MCF7, were used in this study. The effect of dihydrotestosterone (DHT) and heat shock protein 27 (HSP27) on cell proliferation was quantified using the cell counter kit-8 (CCK8) and clonogenic assays in vitro and by a xenograft tumor model in vivo. The expression of the AR and HSP27 was analyzed using western blot, qPCR, and immunofluorescence assays. Complexes of the AR and HSP27 were detected by co-immunoprecipitation (Co-IP). RESULTS: In MDA-MB-453 cells, DHT promoted cell proliferation and stimulated AR and HSP27 translocation from the cytoplasm to the nucleus, whereas, it inhibited MCF7 cell growth, and only the AR translocated into the nucleus. HSP27 knock-down decreased the proliferative ability of MDA-MB-453 cells, which could be rescued by DHT, while HSP27 and DHT had synergistic effects on MCF7 cells. HSP27 phosphorylation was a prerequisite for AR translocation into the nucleus, especially phosphorylation on serine 82. In addition, DHT stimulated the tumorigenic and metastatic capacities of MDA-MB-453 cells, while HSP27 knock-down decreased the rate of tumor formation and induced apoptosis in cells. CONCLUSIONS: The results suggest that HSP27 assists the AR in regulating the malignant behavior of MABC, and these findings might be helpful in the treatment of MABC.

The immunohistochemical expression and potential prognostic value of HDAC6 and AR in invasive breast cancer.

Previous studies have investigated the role of histone deacetylase 6 (HDAC6) in the regulation of androgen receptor (AR) in prostate cancer; however, the role of HDAC6 has not yet been clearly identified in breast cancer. The aim of this study was to examine the expression of HDAC6 and AR, determine the correlation between HDAC6 and AR, and assess the prognostic value of HDAC6 and AR in breast cancer. A total of 228 cases of invasive breast cancer were randomly selected. The expression of HDAC6 and AR was analyzed by immunohistochemistry. χ2 Tests were performed to determine the association between conventional clinicopathological factors and HDAC6, AR, and HDAC6/AR co-expression. Spearman correlation methods were performed to determine the correlation between HDAC6 and AR, and Kaplan-Meier analyses were performed to determine the prognostic impact of HDAC6, AR and HDAC6/AR co-expression; 58.8% (134/228) patients exhibited high expression of HDAC6. High HDAC6 expression was significantly associated with high histologic grade (G3) (P<.001) and p53 overexpression (P=.002). HDAC6 and AR expression levels were significantly associated (r=0.382, P<.01). In estrogen receptor (ER)-negative samples, high expression of HDAC6 was more common in the AR+ groups (P<.001) and correlated with high histologic grade (G3) (P=.009), as well as higher HER2 (P=.006) and p53 levels (P=.012). Higher expression of AR and HDAC6 and HDAC6/AR co-expression had a worse clinical prognosis. The expression levels of HDAC6 and AR are correlated in breast cancer; moreover, HDAC6 and AR have prognostic value in predicting the overall survival (OS) of ER-negative breast cancer patients.

[Effects of Se-riched soybean peptide on antioxidant function in rats of fatty liver caused by high-fat diet].

OBJECTIVE: To explore the effect of Se-riched soybean peptide (SSP) on antioxidant function in rats of fatty liver caused by high-fat diet. METHODS: Forty Wistar rats were divided into 4 groups randomly and fed with standard diet and water (NC), high-fat diet and water (HC), high-fat diet and SSP (0.1 g/d) (SeH), standard diet and SSP (0.1 g/d) (SeN) respectively. After 10 weeks, the rats were killed to investigate the pimelosis level in liver tissues by Sudan III staining and the expression of hepatic GRP78 by immunohistochemical analysis. We also analyzed the changes of liver function, blood lipid, the glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in livers and serum. RESULTS: The pimelosis level, total cholesterol (TC), triglyceride (TG), MDA contents and the expression of GRP78 in HC group were significantly higher than those in NC, SeN, SeH groups. The activities of GSH-Px and SOD in liver and serum were markedly up-regulated in SeH (P < 0.01). There was no significant difference between NC and SeN groups. CONCLUSION: SSP can improve liver cell injury and the antioxidant functions in rats with fatty liver effectively and decrease the expression of GRP78 in liver.