Humans ; Triple Negative Breast Neoplasms/genetics* ; MicroRNAs/genetics* ; Oncogenes ; Cell Line, Tumor ; Cell Proliferation ; Gene Expression Regulation, Neoplastic ; Cell Movement

Breast cancer is a malignant tumor that seriously endangers women's lives. The prognosis of breast cancer patients differs among molecular types. Compared with other subtypes, triple-negative breast cancer (TNBC) has been a research hotspot in recent years because of its high degree of malignancy, strong invasiveness, rapid progression, easy of recurrence, distant metastasis, poor prognosis, and high mortality. Many studies have found that long non-coding RNA (lncRNA) plays an important role in the occurrence, proliferation, migration, recurrence, chemotherapy resistance, and other characteristics of TNBC. Some lncRNAs are expected to become biomarkers in the diagnosis and prognosis of TNBC, and even new targets for its treatment. Based on a PubMed literature search, this review summarizes the progress in research on lncRNAs in TNBC and discusses their roles in TNBC diagnosis, prognosis, and chemotherapy with the hope of providing help for future research.
Humans ; Female ; Triple Negative Breast Neoplasms/genetics* ; RNA, Long Noncoding/genetics* ; Biomarkers, Tumor/genetics* ; Gene Expression Regulation, Neoplastic

OBJECTIVE: To investigate the effect of inhibition of RAB27 protein family, which plays a pivotal role in exosome secretion, on biological behaviors of triple-negative breast cancer cells. METHODS: Quantitative real-time PCR and Western blotting were used to examine the expressions of RAB27 family and exosome secretion in 3 triple-negative breast cancer cell lines (MDA-MB-231, MDA-MB-468, and Hs578T) and a normal breast epithelial cell line (MCF10A). The effect of small interfering RNA (siRNA)-mediated silencing of RAB27a and RAB27b on exosome secretion in the 3 breast cancer cell lines was detected using Western blotting, and the changes in cell proliferation, invasion and adhesion were evaluated. RESULTS: Compared with normal breast epithelial cells, the 3 triple-negative breast cancer cell lines exhibited more active exosome secretion (P < 0.001) and showed significantly higher expressions of RAB27a and RAB27b at both the mRNA and protein levels (P < 0.01). Silencing of RAB27a in the breast cancer cells significantly down-regulated exosome secretion (P < 0.001), while silencing of RAB27b did not significantly affect exosome secretion. The 3 breast cancer cell lines with RAB27a silencing-induced down-regulation of exosome secretion showed obvious inhibition of proliferation, invasion and adhesion (P < 0.01) as compared with the cell lines with RAB27b silencing. CONCLUSION RAB27a plays central role in the exosome secretion in triple-negative breast cancer cells, and inhibiting RAB27a can inhibit the proliferation, invasion and adhesion of the cells.
Humans ; rab GTP-Binding Proteins/metabolism* ; Triple Negative Breast Neoplasms ; Cell Line, Tumor ; rab27 GTP-Binding Proteins/metabolism* ; RNA, Small Interfering/genetics* ; Cell Proliferation/genetics* ; Gene Expression Regulation, Neoplastic

Objective: PD-1/PD-L1 immune checkpoint treatment is effective for some triple-negative breast cancer populations with PD-L1 expression, but the response rate is still not satisfactory. This study aims to explore the mechanism of drug resistance to breast cancer anti-PD-1 therapies and the strategies for overcoming the resistance to PD-1therapies. Methods: By constructing a human triple-negative breast cancer drug-resistant cell line called BT-549R5 and a mouse breast cancer drug-resistant cell line called 4T1R3, and applying the whole-gene shRNA library screening, candidate drug resistance-associated molecules were obtained and verified by cytological experiments. The expression of Tyro3, Axl and MerTK of the TAM family in the 4T1R3 group was tested using the Western blot method. The down-regulation of CDK9 on the effect of T cells killing the BT-549R5 cells was observed through T cell killing tests, while the down-regulation of Tyro3 and CDK9 on the effect of anti-PD-1 therapies for transplanted breast tumors was observed in mouse tumor formation experiments. Results: The cell lines and animal models of breast cancer resistant to PD-1 treatment were successfully constructed. Tyro3, Axl and MerTK were highly expressed in 4T1R3 cells. Whole genome sequencing showed that Tyro3 and CDK9 were highly expressed in BT-549R5 cells. T cell killing experiment showed that the survival rate of BT-549R5 cells in the CDK9 down-regulated group and the control group decreased gradually with the increase of T cells, but the survival rate of BT-549R5 cells in the CDK9 down-regulated group decreased rapidly. Tumor formation experiment in mice showed that under anti-PD-1 treatment, the transplanted tumor in the 4T1R3 cell group grew rapidly compared with the 4T1 cell group (P<0.05), and the tumor volume of the 4T1R3 group was larger than that of the 4T1 group on Day 20. Nevertheless, the tumor growth rates in the CDK9-knockdown 4T1R3 cell group and the Tyro3-knockdown 4T1R3 cell group were similar to that of the 4T1 cell group, and the tumor volumes at day 20 were signiference lower than that of 4T1R3 cell group(P<0.05). Conclusions: Tyro3 and CDK9 are associated with the drug resistance to anti-PD-1 therapies for breast cancer. Inhibiting the expression of Tyro3 and CDK9 can reverse the drug resistance to breast cancer treatment.
Humans ; Animals ; Mice ; c-Mer Tyrosine Kinase/metabolism* ; Receptor Protein-Tyrosine Kinases/genetics* ; Axl Receptor Tyrosine Kinase ; Proto-Oncogene Proteins/metabolism* ; B7-H1 Antigen/genetics* ; Triple Negative Breast Neoplasms/genetics* ; Drug Resistance, Neoplasm ; Biomarkers ; Cell Line, Tumor ; Cyclin-Dependent Kinase 9

Objective: PD-1/PD-L1 immune checkpoint treatment is effective for some triple-negative breast cancer populations with PD-L1 expression, but the response rate is still not satisfactory. This study aims to explore the mechanism of drug resistance to breast cancer anti-PD-1 therapies and the strategies for overcoming the resistance to PD-1therapies. Methods: By constructing a human triple-negative breast cancer drug-resistant cell line called BT-549R5 and a mouse breast cancer drug-resistant cell line called 4T1R3, and applying the whole-gene shRNA library screening, candidate drug resistance-associated molecules were obtained and verified by cytological experiments. The expression of Tyro3, Axl and MerTK of the TAM family in the 4T1R3 group was tested using the Western blot method. The down-regulation of CDK9 on the effect of T cells killing the BT-549R5 cells was observed through T cell killing tests, while the down-regulation of Tyro3 and CDK9 on the effect of anti-PD-1 therapies for transplanted breast tumors was observed in mouse tumor formation experiments. Results: The cell lines and animal models of breast cancer resistant to PD-1 treatment were successfully constructed. Tyro3, Axl and MerTK were highly expressed in 4T1R3 cells. Whole genome sequencing showed that Tyro3 and CDK9 were highly expressed in BT-549R5 cells. T cell killing experiment showed that the survival rate of BT-549R5 cells in the CDK9 down-regulated group and the control group decreased gradually with the increase of T cells, but the survival rate of BT-549R5 cells in the CDK9 down-regulated group decreased rapidly. Tumor formation experiment in mice showed that under anti-PD-1 treatment, the transplanted tumor in the 4T1R3 cell group grew rapidly compared with the 4T1 cell group (P<0.05), and the tumor volume of the 4T1R3 group was larger than that of the 4T1 group on Day 20. Nevertheless, the tumor growth rates in the CDK9-knockdown 4T1R3 cell group and the Tyro3-knockdown 4T1R3 cell group were similar to that of the 4T1 cell group, and the tumor volumes at day 20 were signiference lower than that of 4T1R3 cell group(P<0.05). Conclusions: Tyro3 and CDK9 are associated with the drug resistance to anti-PD-1 therapies for breast cancer. Inhibiting the expression of Tyro3 and CDK9 can reverse the drug resistance to breast cancer treatment.
Humans ; Animals ; Mice ; c-Mer Tyrosine Kinase/metabolism* ; Receptor Protein-Tyrosine Kinases/genetics* ; Axl Receptor Tyrosine Kinase ; Proto-Oncogene Proteins/metabolism* ; B7-H1 Antigen/genetics* ; Triple Negative Breast Neoplasms/genetics* ; Drug Resistance, Neoplasm ; Biomarkers ; Cell Line, Tumor ; Cyclin-Dependent Kinase 9

Triple negative breast cancer (TNBC) is prone to recurrence and metastasis, which is the subtype of poorest prognosis. Chemotherapy is the main treatment, although there is lack of effective adjuvant chemotherapy regimens. The unsatisfactory efficacy of chemotherapy has been a bottleneck in improving the outcome of TNBC. Platinum compounds act directly on DNA to kill tumor cells, and they have a stronger killing effect on tumor cells carrying DNA damage repair (DDR) defects, which is an important entry point to improve the efficacy of TNBC. Biomarkers for predicting the efficacy of platinum drugs in TNBC treatment have always been a hot topic. The DDR pathway contains a large number of related genes, and recent studies have shown that deficiencies in the DDR pathway may be associated with the efficacy of platinum drugs, which is expected to be a biomarker for predicting the efficacy of platinum drugs in breast cancer treatment.
Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; DNA Damage ; DNA Repair ; Humans ; Pharmaceutical Preparations ; Platinum/therapeutic use* ; Platinum Compounds/therapeutic use* ; Triple Negative Breast Neoplasms/genetics*

Objective: To investigate the expression of programmed death ligand-1 (PD-L1, SP142) and PD-L1 (22C3) in triple-negative breast cancer (TNBC), and analyze their correlation with the clinicopathological factors and prognosis. Methods: The clinicopathologic data of 259 patients with TNBC treated in Cancer Hospital from August 2010 to December 2013 were collected. Whole section of surgical tissue samples were collected to conduct PD-L1 (SP142) and PD-L1 (22C3) immunohistochemical (IHC) staining. The PD-L1 expression in tumor cells and tumor infiltrating immune cells were visually assessed respectively, the relationship between PD-L1 expression and clinicopathologic characterizes were analyzed. Univariable and multivariable Cox proportional hazards regression models were used to test the correlations between PD-L1 expression and disease-free survival (DFS) and overall survival (OS). Results: The positive rates of SP142 (immune cell score, ICs≥1%) and 22C3 (combined positive score, CPS≥1) were 42.1%(109/259) and 41.3%(107/259) in TNBC tissues, respectively, with a total coincidence rate of 82.3%. The Kappa value of positive expression cases was 0.571 and the distribution difference of SP142 and 22C3 positive expression cases was statistically significant (P<0.001). The PD-L1 positive patients were less likely to have vascular invasion (P<0.05), but with higher histological grade and Ki-67 proliferation index (P<0.05). The recurrence/metastasis cases(8) of the patients with positive PD-L1 (SP142) was significantly lower than that of patients with negative PD-L1(SP142, 27, P=0.016). The positive expression of PD-L1 (SP142) patients were longer DFS (P=0.019). The OS of patients with positive PD-L1 (SP142) were longer than those with negative PD-L1 (SP142), but without significance (P=0.116). The positive expression of PD-L1 (22C3) was marginally associated with DFS and OS of patients (P>0.05). Conclusions: The expression of PD-L1 (22C3) is different from that of PD-L1 (SP142) in TNBC, and the two antibodies can't be interchangeable for each other in clinical tests. PD-L1 (SP142) status is an independent prognostic factor of DFS in TNBC. The DFS is significantly prolonged in patients with positive expression of PD-L1 (SP142).
B7-H1 Antigen/genetics* ; Humans ; Immunohistochemistry ; Prognosis ; Triple Negative Breast Neoplasms/pathology*

Objective: To investigate the germline mutation status of related genes in breast cancer patients and high-risk individuals by next-generation sequencing. To analyze the correlations between homologous recombination repair (HR) pathway gene mutation status and clinicopathological characteristics of breast cancer patients. To supplement the database of breast cancer related gene mutations in Chinese population. Methods: This study is a cross-sectional study. From October 2020 to September 2021, whole blood samples were collected from 350 breast cancer patients and 49 high-risk individuals, admitted to Peking University People's Hospital and accepted genetic testing voluntarily. Germline mutations in 32 breast cancer related genes were detected by NGS. The clinicopathological characteristics, including age at the onset, family history, unilateral/bilateral tumor, Luminal typing (Luminal A subtype, Luminal B subtype, HER2-enriched subtype and triple negative breast cancer), tumor size and metastasis, were analyzed, and the correlations between HR pathway gene mutation status and clinicopathological characteristics were analyzed by Chi-squared test and Fisher's exact probability test. Results: Among 350 breast cancer patients, 64 (18.3%) cases carried gene pathogenic mutations (including pathogenic and likely pathogenic mutations), including 47 (13.4%) in BRCA1/2, 16 (4.6%) in non-BRCA1/2 genes, 1 (0.3%) in BRCA2 and FANCL. Among 49 high-risk individuals, 7 (14.3%) cases carried gene pathogenic mutations, including 6 (12.3%) in BRCA1/2 and 1 (2%) in ATM genes. BRCA1/2 pathogenic mutations were associated with age at the onset (18%, 8.7%, χ²=6.346, P=0.012), and the BRCA1/2 pathogenic mutation frequency was higher in patients diagnosed at age ≤45 years. HR pathway gene mutations (including pathogenic, likely pathogenic and uncertain significance mutations) were correlated with unilateral/bilateral tumor (49.5%, 68.4%, χ²=4.841, P=0.028) and Luminal typing (45.7%, 62.2%, 32%, 60%, χ²=12.004, P=0.007), and the HR mutation frequencies were higher in patients with bilateral tumor, Luminal B breast cancer and triple negative breast cancer (TNBC). Conclusion: The BRCA1/2 pathogenic mutation frequency in high-risk individuals is similar to that in breast cancer patients, and BRCA1/2 testing is helpful to guide breast cancer screening and prevention in high-risk individuals. Patients with early onset breast cancer, bilateral breast cancer, Luminal B breast cancer and TNBC have higher mutation frequencies of HR pathway genes, and HR pathway genes testing should be conducted as soon as possible to provide laboratory evidence for diagnosis, treatment, prognosis and risk evaluation of breast cancer.
BRCA1 Protein/genetics* ; BRCA2 Protein/genetics* ; Breast Neoplasms/pathology* ; Cross-Sectional Studies ; Female ; Genetic Predisposition to Disease ; Germ-Line Mutation ; High-Throughput Nucleotide Sequencing ; Humans ; Middle Aged ; Mutation ; Recombinational DNA Repair ; Triple Negative Breast Neoplasms/pathology*

Biomarkers, Tumor/genetics* ; Breast Neoplasms/genetics* ; Female ; Humans ; Receptor, ErbB-2/genetics* ; Triple Negative Breast Neoplasms/genetics*

According to the classification presented by Lehmann BD (2016), triple-negative breast cancer (TNBC) is a heterogeneous group of malignant tumors with four specific subtypes: basal-like (subtype 1 and subtype 2), mesenchymal, and luminal androgen receptor (LAR) subtypes. The basal-like subtypes of carcinomas predominate in this group, accounting for up to 80% of all cases. Despite the significantly lower proportions of mesenchymal and LAR variants in the group of breast carcinomas with a TNBC profile, such tumors are characterized by aggressive biological behavior. To this end, the LAR subtype is of particular interest, since the literature on such tumors presents different and even contradictory data concerning the disease course and prognosis. This review is devoted to the analysis of the relevant literature, reflecting the main results of studies on the molecular properties and clinical features of the disease course of LAR-type TNBC carcinomas.
Carcinoma ; Humans ; Receptors, Androgen/genetics* ; Triple Negative Breast Neoplasms/pathology*