miR-190 suppresses breast cancer metastasis by regulation of TGF-ß-induced epithelial-mesenchymal transition.

BACKGROUND: Breast cancer is the most common cancer among women worldwide and metastasis is the leading cause of death among patients with breast cancer. The transforming growth factor-ß (TGF-ß) pathway plays critical roles during breast cancer epithelial-mesenchymal transition (EMT) and metastasis. SMAD2, a positive regulator of TGF-ß signaling, promotes breast cancer metastasis through induction of EMT. METHODS: The expression of miR-190 and SMAD2 in breast cancer tissues, adjacent normal breast tissues and cell lines were determined by RT-qPCR. The protein expression levels and localization were analyzed by western blotting and immunofluorescence. ChIP and dual-luciferase report assays were used to validate the regulation of ZEB1-miR-190-SMAD2 axis. The effect of miR-190 on breast cancer progression was investigated both in vitro and in vivo. RESULTS: miR-190 down-regulation is required for TGF-ß-induced EMT. miR-190 suppresses breast cancer metastasis both in vitro and in vivo by targeting SMAD2. miR-190 expression is down-regulated and inversely correlates with SMAD2 in breast cancer samples, and its expression level was associated with outcome in patients with breast cancer. Furthermore, miR-190 is transcriptionally regulated by ZEB1. CONCLUSIONS: Our data uncover the ZEB1-miR-190-SMAD2 axis and provide a mechanism to explain the TGF-ß network in breast cancer metastasis.

miR-485-5p suppresses breast cancer progression and chemosensitivity by targeting survivin.

Breast cancer is the most common cancer among women worldwide. Chemoresistance remains to be a considerable obstacle in breast cancer therapy and it is often involves dysregulation of a variety of microRNAs (miRNAs). miR-485-5p functions as a tumor suppressor in several types of human cancers. However, its role in breast cancer chemosensitivity have not been determined. In the present study, we demonstrated that overexpression of miR-485-5p suppresses breast cancer progression and enhances chemosensitivity both in vitro and in vivo. Further study demonstrated that miR-485-5p directly targeted the 3'-untranslated region of survivin and overexpression of survivin overcomes the miR-485-5p induced effects on breast cancer. In conclusion, our study identified that miR-485-5p suppresses cancer progression and enhances the chemosensitivity by targeting survivin. Targeting survivin by miR-485-5p may provide a potential approach to reverse chemosensitivity in breast cancer cells.

Serum deprivation response inhibits breast cancer progression by blocking transforming growth factor-ß signaling.

Serum deprivation response (SDPR), a key substrate for protein kinase C, play a critical role in inducing membrane curvature and participate in the formation of caveolae. However, the function of SDPR in cancer development and progression is still not clear. Here, we found that SDPR is downregulated in human breast cancer. Overexpression of SDPR suppresses cell proliferation and invasion in MDA-MB-231 cells, while depletion of SDPR promotes cell proliferation and invasion in MCF10A cells. Subsequently, SDPR depletion induces epithelial-mesenchymal transition (EMT)-like phenotype. Finally, knockdown of SDPR activates transforming growth factor-ß (TGF-ß) signaling by upregulation of TGF-ß1 expression. In conclusion, our results showed that SDPR inhibits breast cancer progression by blocking TGF-ß signaling. Serum deprivation response suppresses cell proliferation and invasion in breast cancer cells. SDPR depletion induces epithelial-mesenchymal transition by activation of TGF-ß signaling.

The role of surgery on locoregional treatment of patients with breast cancer newly diagnosed with ipsilateral supraclavicular lymph node metastasis.

Background: Radiotherapy is a practical locoregional treatment approach for women with breast cancer who show ipsilateral supraclavicular lymph node metastasis (ISLNM) on diagnosis. However, there is controversy around the role of supraclavicular lymph node dissection. Therefore, we aimed to study the significance of supraclavicular surgery based on radiotherapy. Patients and Methods: We retrospectively reviewed the data of 142 patients with breast cancer who presented with isolated ISLNM and received radiotherapy between the years 2000 and 2016. We also defined the effect of surgery on locoregional treatment of these patients by analyzing the prognostic factors for recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and overall survival (OS). Results: We observed that, of the 142 patients, 104 who received radiotherapy underwent supraclavicular lymph node dissection. Also, among the study group, the progesterone receptor (PR) status (P = 0.044) and the number of axillary lymph nodes (ALNs) involved (P = 0.002) were significant independent predictors of RFS. Also, tumor size (P = 0.007), PR (P < 0.001), and number of ALNs (P < 0.001) were independent predictors of DMFS and were statistically significant. Also, PR was an independent prognostic factor of OS (P = 0.033), whereas the supraclavicular surgery was not an independent prognostic factor for RFS, DMFS, and OS. Furthermore, our study focused on 92 patients with negative estrogen receptors (ERs). The result showed that supraclavicular surgery was statistically significant for RFS (P = 0.023); no significant differences in DMFS and OS were found between patients who received supraclavicular surgery and those who did not. Conclusion: Radiotherapy may be the primary locoregional treatment approach for patients with breast cancer who present with newly diagnosed ISLNM. Additionally, supraclavicular surgery may be more appropriate for patients with negative ER who received radiotherapy.

Estrogen receptor-α-miR-1271-SNAI2 feedback loop regulates transforming growth factor-ß-induced breast cancer progression.

BACKGROUND: Breast cancer is the most common cancer among women worldwide, and approximately 70% of breast cancers are hormone receptor-positive and express estrogen receptor-α (ERα) or/and progesterone receptor. ERα has been identified to promote the growth of primary breast cancer, however, it can also antagonize signaling pathways that lead to epithelial-mesenchymal transition (EMT), including transforming growth factor-ß (TGF-ß) signaling. miRNA alteration or dysfunction is involved in cancer development and progression. Although miR-1271 has identified as a tumor suppressor in various cancers, the role of miR-1271 in breast cancer is still limited. METHODS: The effect of miR-1271 on breast cancer progression was investigated both in vitro and in vivo. The EMT-related protein expression levels and localization were analyzed by western blotting and immunofluorescence, respectively. Chromatin immunoprecipitation and dual-luciferase reporter assays were used to validate the regulation of ERα-miR-1271-SNAI2 feedback loop. RESULTS: miR-1271 suppresses breast cancer progression and EMT phenotype both in vitro and in vivo by targeting SNAI2. Estrogen reverses TGF-ß-induced EMT in a miR-1271 dependent manner. Furthermore, ERα transactivates the miR-1271 expression and is also transcriptionally repressed by SNAI2. CONCLUSIONS: Our data uncover the ERα-miR-1271-SNAI2 feedback loop and provide a mechanism to explain the TGF-ß network in breast cancer progression.

miR-190 enhances endocrine therapy sensitivity by regulating SOX9 expression in breast cancer.

BACKGROUND: Breast cancer is the most common cancer among women worldwide, and approximately 70% of breast cancers are hormone receptor-positive and express estrogen receptor-α (ERα) or/and progesterone receptor. Therapies targeting ERα have been successfully used in patients with ERα+ breast cancer. However, intrinsic or acquired resistance to anti-estrogen therapy presents a major challenge. The Wnt/ß-catenin signaling pathway regulates various processes that are important for cancer progression, and emerging evidences have shown a close interaction between Wnt/ß-catenin and ERα signaling. miR-190 is also involved in ER signaling and our previous study indicated that miR-190 suppresses breast cancer metastasis. METHODS: The effect of miR-190 on breast cancer anti-estrogen sensitivity was investigated both in vitro and in vivo. The protein expression levels and localization were analyzed by western blotting and immunofluorescence, respectively. Chromatin immunoprecipitation and dual-luciferase reporter assays were used to validate the regulation of the zinc-finger E-box binding homeobox 1/ ERα-miR-190-SRY-related high mobility group box 9 (ZEB1/ERα-miR-190-SOX9) axis. RESULTS: miR-190 increased the anti-estrogen sensitivity of breast cancer cells both in vitro and in vivo. miR-190 inhibited Wnt/ß-catenin signaling by targeting SOX9, and its expression inversely correlated with that of SOX9 in breast cancer samples. Furthermore, ERα and ZEB1 competitively regulated miR-190 expression. CONCLUSIONS: Our data uncover the ZEB1/ERα-miR-190-SOX9 axis and suggest a mechanism by which the Wnt/ß-catenin signaling pathway is involved in breast cancer anti-estrogen therapy.

SNHG5 Promotes Breast Cancer Proliferation by Sponging the miR-154-5p/PCNA Axis.

Breast cancer is the most common malignant tumor and the main cause of cancer-associated mortality in females worldwide. Long non-coding RNAs (lncRNAs) have been reported to play vital roles in breast cancer development and progression; however, our understanding of most lncRNAs in breast cancer is still limited. In this study, we demonstrated that small nucleolar RNA host gene 5 (SNHG5) promotes breast cancer cell proliferation both in vitro and in vivo, and depletion of SNHG5 significantly led to cell-cycle arrest at G1 phase. Accumulating evidence has shown that many lncRNA transcripts could function as competing endogenous RNAs (ceRNAs) by competitively binding common microRNAs (miRNAs). We found that SNHG5 acts as a sponge for miR-154-5p, reducing its ability to repress proliferating cell nuclear antigen (PCNA). SNHG5 promoted breast cancer proliferation and cell-cycle progression by upregulation of PCNA expression. Clinically, we observed an increased SNHG5 expression in breast cancer, whereas miR-154-5p was decreased in breast cancer tissues compared with the adjacent normal breast tissues. Furthermore, the SNHG5 expression was significantly negatively correlated with miR-154-5p expression. Taken together, our data uncover the SNHG5-miR-154-5p-PCNA axis and provide a novel mechanism to explain breast cancer proliferation.

The combined pN stage and breast cancer subtypes in breast cancer: a better discriminator of outcome can be used to refine the 8th AJCC staging manual.

BACKGROUND: pN stage and breast cancer subtypes (BCS) are both well-recognized prognostic indicators. Our previous work has highlighted that patients even with the same pN stage exhibited a significant survival difference in different BCS. Given this achievement, we hypothesized that a statistical interaction might exist between pN stage and BCS. The aim of this retrospective cohort study was to compare the prognostic value of the combined pN stage and BCS (pNnew stage) with either pN stage or BCS alone, and to determine if this combined new stage could serve as an alternative discriminator of outcome. METHODS: We combined pN stage and BCS to create a new variable named pNnew stage and then divided it into four groups: pN0new, pN1new, pN2new, and pN3new. Survival analysis was performed with the use of the Kaplan-Meier method and the log-rank test was used for univariate analysis. For multivariate analysis, cox proportional hazard models were applied, allowing for the estimation of disease-free survival (DFS). To assess discriminatory accuracy of the models, we compared the area under the receiver-operating characteristic curve (AUROC), the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) values. Then, we used this pNnew stage to generate a TNnewM staging system according to the 7th AJCC staging system. RESULTS: A statistical interaction between pN stage and BCS was found. In multivariate survival analysis, the pNnew stage has been confirmed as an independent prognostic variable of 5-year DFS. The pNnew stage, with a smaller AIC or BIC value and larger AUROC, was a more powerful predictor of DFS than either pN stage or BCS alone. Results were validated in a separate cohort of patients. The TNnewM stage proposed in our present study was found comparable to the new 8th AJCC edition which includes anatomic T, N, and M plus tumor grade and the status of the biomarkers Her-2, ER, and PR with respect to prognostic value for breast cancer patients. CONCLUSIONS: The pNnew stage (combined pN stage and BCS) appears to be a more powerful predictor and discriminator for the outcome of breast cancer, as compared to pN stage or BCS alone, and the TNnewM stage may serve as a simple, easy-to-use alternative to the 8th AJCC edition staging manual.

The prognostic value of node status in different breast cancer subtypes.

Nodal metastases and breast cancer subtypes (BCS) are both well-recognized prognostic indicators. However, the association between nodal metastases and BCS, and the prognostic value of nodal metastases in different BCS are still remains unclear. Our aim was to investigate the association between nodal metastases and BCS, and the prognostic value of nodal metastases in the different BCS.We found that the breast cancer subtype was closely associated with the pN stage. pN stage and breast cancer subtype were significantly associated with disease-free survival. The subgroup analysis showed that the patients in higher pN stage had a poor outcome than patients in lower pN stage in each breast cancer subtype. Furthermore, when the analysis was stratified by breast cancer subtype, we found that even in the same pN stage (pN0-pN2), there was significant survival difference among patients in different BCS, and Luminal A breast cancer patients had the best survival outcome. However, there were no significant survival difference between Luminal A patients and other breast cancer subtype when patients in pN3 stage. Thus, our study suggested that both lymph node status and molecular subtype played important roles in the outcome of breast cancer patients and they cannot replace each other.