Metastatic disease is responsible for over 90% of death in patients with breast cancer. Therefore, identifying the molecular mechanisms that regulate metastasis and developing useful therapies are crucial tasks. Long non-coding RNAs (lncRNAs), which are non-coding transcripts with >200 nucleotides, have recently been identified as critical molecules for monitoring cancer progression. This study examined the novel lncRNAs involved in the regulation of tumor progression in breast cancer. This study identified 73 metastasis-related lncRNA candidates from comparison of paired isogenic high and low human metastatic breast cancer cell lines, and their expression levels were verified in clinical tumor samples by using The Cancer Genome Atlas. Among the cell lines, a novel lncRNA, LOC550643, was highly expressed in breast cancer cells. Furthermore, the high expression of LOC550643 was significantly correlated with the poor prognosis of breast cancer patients, especially those with triple-negative breast cancer. Knockdown of LOC550643 inhibited cell proliferation of breast cancer cells by blocking cell cycle progression at S phase. LOC550643 promoted important in vitro metastatic traits such as cell migration and invasion. Furthermore, LOC550643 could inhibit miR-125b-2-3p expression to promote breast cancer cell growth and invasiveness. In addition, by using a xenograft mouse model, we demonstrated that depletion of LOC550643 suppressed the lung metastatic potential of breast cancer cells. Overall, our study shows that LOC550643 plays an important role in breast cancer cell metastasis and growth, and LOC550643 could be a potential diagnosis biomarker and therapeutic target for breast cancer.

Breast cancer is a heterogeneous disease, and the survival rate of patients with breast cancer strongly depends on their stage and clinicopathological features. Chemoradiation therapy is commonly employed to improve the survivability of patients with advanced breast cancer. However, the treatment process is often accompanied by the development of drug resistance, which eventually leads to treatment failure. Metabolism reprogramming has been recognized as a mechanism of breast cancer resistance. In this study, we established a doxorubicin-resistant MCF-7 (MCF-7-D500) cell line through a series of long-term doxorubicin in vitro treatments. Our data revealed that MCF-7-D500 cells exhibited increased multiple-drug resistance, cancer stemness, and invasiveness compared with parental cells. We analyzed the metabolic profiles of MCF-7 and MCF-7-D500 cells through liquid chromatography–mass spectrometry. We observed significant changes in 25 metabolites, of which, 21 exhibited increased levels (>1.5-fold change and p < 0.05) and 4 exhibited decreased levels (<0.75-fold change and p < 0.05) in MCF-7 cells with doxorubicin resistance. These results suggest the involvement of metabolism reprogramming in the development of drug resistance in breast cancer, especially the activation of glycolysis, the tricarboxylic acid (TCA) cycle, and the hexamine biosynthesis pathway (HBP). Furthermore, most of the enzymes involved in glycolysis, the HBP, and the TCA cycle were upregulated in MCF-7-D500 cells and contributed to the poor prognosis of patients with breast cancer. Our findings provide new insights into the regulation of drug resistance in breast cancer, and these drug resistance-related metabolic pathways can serve as targets for the treatment of chemoresistance in breast cancer.

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Objective: The current study aimed to retrospectively assess the cancer detection rate of needle localization biopsy of breast microcalcifications undetectable on sonography. Materials and Methods: Patients who underwent mammography-guided needle localization biopsy of breast microcalcifications undetectable on sonography from January 2005 to December 2017 were included in the study. Patients with incomplete medical records were excluded from the study. Patient mammograms were categorized using the Breast Imaging-Reporting and Data System (BI-RADS) assessment criteria. The percentages of benign and malignant lesions were determined by pathological examination of surgically recovered specimens. Correlation between preoperative imaging assessment and final diagnosis was investigated, and the complications associated with the procedures were recorded. Results: A total of 301 needle-localized biopsies were performed under mammographic guidance. The mean age of the patients was 58.18 ± 7.73 years. The overall ductal carcinoma in situ (DCIS) and cancer detection rate was 23.3%. The proportion of patients with BI-RADS 0 category and undergoing second mammography was higher in the DCIS and cancer group. A total of 227 patients did not undergo second mammography. Of these patients, 70 demonstrated BI-RADS 4 category, 34 were diagnosed with DCIS, and 5 were diagnosed with breast cancer during subsequent follow-up. Conclusion: Needle-localized excision of microcalcifications undetectable on sonography has high detection rate for early stage of breast cancer with low risk of associated complications. Regular mammography is a satisfactory follow-up tool for female patients with microcalcifications in the breasts. Additional studies should be performed to compare between needle-localized excision and vacuum-assisted breast biopsy.