Background: NDRG2 (N-Myc downstream-regulated gene 2) was initially cloned in our laboratory. Previous results have shown that NDRG2 expressed differentially in normal and cancer tissues. Specifically, NDRG2 mRNA was down-regulated or undetectable in several human cancers, and over-expression of NDRG2 inhibited the proliferation of cancer cells. NDRG2 also exerts important functions in cell differentiation and tumor suppression. However, it remains unclear whether NDRG2 participates in carcinogenesis of the thyroid. Methods: In this study, we investigated the expression profile of human NDRG2 in thyroid adenomas and carcinomas, by examining tissues from individuals with thyroid adenomas (n = 40) and carcinomas (n = 35), along with corresponding normal tissues. Immunohistochemistry, quantitative RT-PCR and western blot methods were utilized to determine both the protein and mRNA expression status of Ndrg2 and c-Myc. Results: The immunostaining analysis revealed a decrease of Ndrg2 expression in thyroid carcinomas. When comparing adenomas or carcinomas with adjacent normal tissue from the same individual, the mRNA expression level of NDRG2 was significantly decreased in thyroid carcinoma tissues, while there was little difference in adenoma tissues. This differential expression was confirmed at the protein level by western blotting. However, there were no significant correlations of NDRG2 expression with gender, age, different histotypes of thyroid cancers or distant metastases. Conclusion: Our data indicates that NDRG2 may participate in thyroid carcinogenesis. This finding provides novel insight into the important role of NDRG2 in the development of thyroid carcinomas. Future studies are needed to address whether the down-regulation of NDRG2 is a cause or a consequence of the progression from a normal thyroid to a carcinoma.

Docetaxel is commonly used as an effective chemotherapeutic agent in breast cancer treatment, but the underlying mechanisms of drug resistance are not fully understood. The purpose of this study was to investigate the possible role of miR-129-3p in breast cancer cell resistance to docetaxel. MiR-129 and miR-129-3p inhibitor were transfected into breast cancer cells to investigate their effects on chemoresistance to docetaxel. The function of miR-129-3p was evaluated by apoptosis, cell proliferation and cell cycle assays. We found that miR-129-3p was up-regulated in MDA-MB-231/Doc cells, concurrent with CP110 down-regulation, compared to the parental MDA-MB-231 cells. In vitro drug sensitivity assays demonstrated that miR-129-3p inhibition sensitized MDA-MB-231/Doc and MCF-7 cells to docetaxel, whereas miR-129 overexpression enhanced MDA-MB-231 and MCF-7 cell resistance to docetaxel. Ectopic miR-129 expression reduced CP110 expression and the luciferase activity of a CP110 3′ untranslated region-based reporter construct in MDA-MB-231 cells, suggesting that CP110 is a direct miR-129-3p target. We demonstrated that restoration of CP110 expression in MDA-MB-231 and MCF-7 cells by miR-129 overexpression rendered the cells sensitive to docetaxel. In a nude xenograft model, miR-129 up-regulation significantly decreased MDA-MB-231 cells’ response to docetaxel. Our findings suggest that miR-129-3p down-regulation potentially sensitizes breast cancer cells to docetaxel treatment.

Background: Breast cancer is the most frequently diagnosed cancer and a leading cause of cancer-related death in women. Endoplasmic reticulum stress (ERS) plays a crucial role in the pathogenesis of several malignancies. However, the prognostic value of ERS-related genes in breast cancer has not been thoroughly investigated.Methods: We downloaded and analyzed expression profiling data for breast invasive carcinoma samples in The Cancer Genome Atlas-Breast Invasive Carcinoma (TCGA-BRCA) and identified 23 ERS-related genes differentially expressed between the normal breast tissue and primary breast tumor tissues. We constructed and validated risk models using external test datasets. We assessed the differences in sensitivity to common antitumor drugs between high- and low-scoring groups using the Genomics of Drug Sensitivity in Cancer (GDSC) database, evaluated the sensitivity of patients in high- and low-scoring groups to immunotherapy using the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm, and assessed immune and stromal cell infiltration in the tumor microenvironment (TME) using the Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE) algorithm. We also analyzed the expression of independent factors in the prognostic model using the Western-blot analysis for correlation in relation to breast cancer.Results: Using multivariate Cox analysis, FBXO6, PMAIP1, ERP27, and CHAC1 were identified as independent prognostic factors in patients with breast cancer. The risk score in our model was defined as the endoplasmic reticulum score (ERScore). ERScore had high predictive power for overall survival in patients with breast cancer. The high-ERScore group exhibited a worse prognosis, lower drug sensitivity, and lower immunotherapy response and immune infiltration than did the low-ERScore group. Conclusions based on ERScore were consistent with Western-blot results.Conclusion: We constructed and validated for the first time an endoplasmic reticulum stress-related molecular prognostic model for breast cancer with reliable predictive properties and good sensitivity, as an important addition to the prognostic prediction model for breast cancer.

Breast cancer seriously endangers women’s health worldwide. Protein arginine methyltransferase 5 (PRMT5) is highly expressed in breast cancer and represents a potential druggable target for breast cancer treatment. However, because the currently available clinical PRMT5 inhibitors are relatively limited, there is an urgent need to develop new PRMT5 inhibitors. Our team previously found that the FDA-approved drug tadalafil can act as a PRMT5 inhibitor and enhance the sensitivity of breast cancer patients to doxorubicin treatment. To further improve the binding specificity of tadalafil to PRMT5, we chemically modified tadalafil, and designed three compounds, A, B, and C, based on the PRMT5 protein structure. These three compounds could bind to PRMT5 through different binding modes and inhibit histone arginine methylation. They arrested the proliferation and triggered the apoptosis of breast cancer cells in vitro and also promoted the antitumor effects of the chemotherapy drugs cisplatin, doxorubicin, and olaparib in combination regimens. Among them, compound A possessed the highest potency. Finally, the anti-breast cancer effects of PRMT5 inhibitor A and its ability to enhance chemosensitivity were further verified in a xenograft mouse model. These results indicate that the new PRMT5 inhibitors A, B, and C may be potential candidates for breast cancer treatment.