Proteomic Landscape of Exosomes Reveals the Functional Contributions of CD151 in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. Patients with TNBC have poor overall survival because of limited molecular therapeutic targets. Recently, exosomes have been recognized as key mediators in cancer progression, but the molecular components and function of TNBC-derived exosomes remain unknown. The main goal of this study was to reveal the proteomic landscape of serum exosomes derived from ten patients with TNBC and 17 healthy donors to identify potential therapeutic targets. Using a tandem mass tag-based quantitative proteomics approach, we characterized the proteomes of individual patient-derived serum exosomes, identified exosomal protein signatures specific to patients with TNBC, and filtered out differentially expressed proteins. Most importantly, we found that the tetraspanin CD151 expression levels in TNBC-derived serum exosomes were significantly higher than those exosomes from healthy subjects, and we validated our findings with samples from 16 additional donors. Furthermore, utilizing quantitative proteomics approach to reveal the proteomes of CD151-deleted exosomes and cells, we found that exosomal CD151 facilitated secretion of ribosomal proteins via exosomes while inhibiting exosome secretion of complement proteins. Moreover, we proved that CD151-deleted exosomes significantly decreased the migration and invasion of TNBC cells. This is the first comparative study of the proteomes of TNBC patient-derived and CD151-deleted exosomes. Our findings indicate that profiling of TNBC-derived exosomal proteins is a useful tool to extend our understanding of TNBC, and exosomal CD151 may be a potential therapeutic target for TNBC.

Development and validation of an extended Cox prognostic model for patients with ER/PR+ and HER2- breast cancer: a retrospective cohort study.

BACKGROUND: The purpose of this study was to explore a new estrogen receptor (ER) and/or progesterone receptor (PR)+ and human epidermal growth factor receptor 2 (HER2)- breast cancer prognostic model, called the extended Cox prognostic model, for determining the cutoff values for multiple continuous prognostic factors and their interaction via the new model concept and variable selection method. METHODS: A total of 335 patients with ER/PR+ and HER2- breast cancer were enrolled for the final analysis. The primary endpoint was breast cancer-specific mortality (BCSM). Prognostic factors (histological grade, histological type, stage, T, N, lymphovascular invasion (LVI), P53, Ki67, ER, PR, and age) were included in this study. The four continuous variables (Ki67, ER, PR, and age) were partitioned into a series of binary variables that were fitted in the multivariate Cox analysis. A smoothly clipped absolute deviation (SCAD) variable selection method was used. Model performance was expressed in discrimination and calibration. RESULTS: We developed an extended Cox model with a time threshold of 164-week (more than 3 years) postoperation and developed a user-friendly nomogram based on our extended Cox model to facilitate clinical application. We found that the cutoff values for PR, Ki67, and age were 20%, 60%, and 41-55 years, respectively. There was an interaction between age and PR for patients aged ≥ 41 years and PR ≥ 20% at 164-week postoperation: the older the patients with ER/PR+, HER2-, and PR ≥ 20% were, the lower the survival and more likely to recur and metastasize exceeding 164 weeks (more than 3 years) after surgery. CONCLUSIONS: Our study offers guidance on the prognosis of patients with ER/PR+ and HER2- breast cancer in China. The new concept can inform modeling and the determination of cutoff values of prognostic factors in the future.

Overexpression of Raf-1 in basal-like carcinoma of the breast: correlation with clinicopathology and prognosis.

AIM OF THE STUDY: Increased Raf-1 expression has been associated with an aggressive behaviour in some carcinomas such as pulmonary carcinoma and renal carcinoma. However, its role in breast cancer, especially in basal-like carcinoma of the breast (BLBC), has not been defined. MATERIAL AND METHODS: The current study attempted to investigate the expression pattern of Raf-1 protein in BLBC, in relation to the biological behaviour and prognosis of the carcinoma. Expression of Raf-1 was detected by immunohistochemistry in carcinoma specimens from 74 cases of BLBC, and associations between their expression and the clinicopathological characteristics were statistically assessed. RESULTS: The patients' age, tumour size, BRCA1, and p53 protein expression was not significantly different between the Raf-1-positive and Raf-1-negative expression groups (p > 0.05). The proportion of histological grade 3 tumours was not significantly higher in the Raf-1 positive group than that of grade 2 tumours (p > 0.05). However, positive cytoplasmic Raf-1 expression was positively correlated to Ki-67 expression (p < 0.05). Also, increased Raf-1 protein was found to exert an unfavourable impact on patients' axillary lymph node metastasis and overall survival (p < 0.05). CONCLUSIONS: The study implies that positive Raf-1 expression in BLBC is associated with a more aggressive phenotype and could be considered as a new prognostic biomarker for poor survival in BLBC patients.

Cellular regulation and stability of DNA replication forks in eukaryotic cells.

Genomic DNA in yeast and human cells harbors approximately 2000 and a few million DNA replication barriers, respectively. These barriers result in frequent replication fork stalling, causing tremendous stress on DNA replication. Stalled replication forks are unstable and tend to collapse as a result of the intrinsic instability of replisomes. Checkpoint and chromsfork (chromatin compaction stabilizes stalling replication forks) controls have been shown to be essential for stabilizing stalled replication forks. However, their underlying regulatory mechanisms are only partially understood. To give some perspectives, we must know the current situation in the field. Thus, this review succinctly goes through our current understanding of replication barriers, replisomes, replication forks, types of fork collapse, checkpoint, and chromsfork control. We also give our views on some controversial issues in this field, and hopefully, they will be helpful for future studies. In the final section on perspectives, some key questions are outlined. Due to space limitations, many excellent works are not discussed here, and readers are referred to other excellent review articles.

RNA polymerase III directly participates in DNA homologous recombination.

A recent study showed that RNA transcription is directly involved in DNA homologous recombination (HR). The first step in HR is end resection, which degrades a few kilobases or more from the 5'-end strand at DNA breaks, but the 3'-end strand remains strictly intact. Such protection of the 3'-end strand is achieved by the transient formation of an RNA-DNA hybrid structure. The RNA strand in the hybrid is newly synthesized by RNA polymerase III. The revelation of the existence of an RNA-DNA hybrid intermediate should further help resolve several long-standing questions of HR. In this article, we also put forward our views on some controversial issues related to RNA-DNA hybrids, RNA polymerases, and the protection of 3'-end strands.

Endothelial Nogo-B Suppresses Cancer Cell Proliferation via a Paracrine TGF-ß/Smad Signaling.

Nogo-B has been reported to play a critical role in angiogenesis and the repair of damaged blood vessels; however, its role in the tumor microenvironment remains unclear. Here, we observed the differential expression of Nogo-B in endothelial cells from hepatocellular carcinoma (HCC) and glioma samples. Downregulation of Nogo-B expression correlated with the malignant phenotype of cancer and a poor prognosis for patients. In subsequent studies, endothelial Nogo-B inhibition robustly promoted the growth of HCC or glioma xenografts in nude mice. Intriguingly, endothelial Nogo-B silencing dramatically suppressed endothelial cell expansion and tumor angiogenesis, but potently enhanced the proliferation of neighboring HCC and glioma cells. Based on the results of the ELISA assay, Nogo-B silencing reduced TGF-ß production in endothelial cells, which attenuated the phosphorylation and nuclear translocation of Smad in neighboring cancer cells. The endothelial Nogo-B silencing-mediated increase in cancer cell proliferation was abolished by either a TGF-ß neutralizing antibody or TGF-ß receptor inhibitor, indicating the essential role for TGF-ß in endothelial Nogo-B-mediated suppression of cancer growth. These findings not only broaden our understanding of the crosstalk between cancer cells and endothelial cells but also provide a novel prognostic biomarker and a therapeutic target for cancer treatments.

Prognostic factors for breast cancer squamous cell carcinoma and nomogram development for prediction: population-based research.

BACKGROUND: To investigate the prognostic survival factors of breast squamous cell carcinoma (BSqCC) and develop a comprehensive nomogram for predicting the survival of breast cancer squamous cell carcinoma. METHODS: Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with BSqCC from 1973 to 2015. The data was obtained using SEER Stat 8.3.4 software, collated, and analyzed by Excel 2016 software and SPSS (v25.0). Kaplan-Meier curves were used for survival analysis. The variables obtained by univariate analysis were introduced into the Cox proportional hazard model for multivariate analysis. The risk factors affecting the prognosis of BSqCC were obtained. P<0.05 was considered statistically significant. The independent prognostic factors of BSqCC were integrated and used to construct nomograms. RESULTS: A total of 739 patients with BSqCC was included. The median age of diagnosis was 66 years. In most cases, the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was negative. One-third of the cases underwent breast-conserving surgery, and more than half of the cases underwent mastectomy (unilateral or bilateral). The 1-year survival rate was 81.2%, the 3-year survival rate was 62.9%, the 5-year survival rate was 54.4%, and the 10-year survival rate was 41.4%. Age (χ2=71.050, P<0.001), marital status (χ2=37.560, P<0.001), tumor size (χ2=27.931, P<0.001), surgical procedure (χ2=74.185, P<0.001), the number of positive lymph nodes (χ2=38.542, P<0.001), and the primary site (χ2=59.217, P<0.001) were significantly correlated with patient survival time. Among them, marital status (HR: 0.502, 95% CI: 0.318-0.794), age (HR: 2.186, 95% CI: 1.234-3.875), surgical procedure (HR: 1.03, 95% CI: 1.01-1.051), tumor size (HR: 1.505, 95% CI: 1.083-2.091) and the number of positive lymph nodes (HR: 1.277, 95% CI: 1.087-1.499) were independent risk factors for the survival of BSqCC. Five independent prognostic factors were then integrated for the construction of nomograms. CONCLUSIONS: BSqCC was a malignant tumor with a low survival rate. Age of onset was typically at an older age; mostly middle-aged and seniors. Marital status, age, surgical procedure, tumor size, and several positive lymph nodes were independent predictors of patient survival. At the same time, we developed a prognostic nomogram with excellent discrimination for breast cancer squamous cell carcinoma; therefore, it could help clinicians make decisions on a personal basis.

Long non-coding RNA DILC suppresses bladder cancer cells progression.

Accumulative researches have demonstrated the critical functions of long non-coding RNAs (lncRNAs) in the progression of malignant tumors, including bladder cancer (BC). Our previous studies showed that lnc-DILC was an important tumor suppressor gene in both liver cancer and colorectal cancer. However, the role of lnc-DILC in BC remains to be elucidated. In the present study, we for first found that lnc-DILC was downregulated in human bladder cancer tissues. Lnc-DILC overexpression suppressed the proliferation, metastasis and expansion of bladder cancer stem cells (CSCs). Mechanically, lnc-DILC suppressed BC cells progression via STAT3 pathway. Special STAT3 inhibitor S3I-201 diminished the discrepancy of growth, metastasis and self-renewal ability between lnc-DILC-overexpression BC cells and their control cells, which further confirmed that STAT3 was acquired for lnc-DILC-disrupted BC cell growth, metastasis and self-renewal. Taken together, our results suggest that lnc-DILC is a novel bladder tumor suppressor and indicate that lnc-DILC inhibits BC progression via inactivating STAT3 signaling.

Characterization of mutations in BRCA1/2 and the relationship with clinic-pathological features of breast cancer in a hereditarily high-risk sample of chinese population.

The database of BRCA1/2 mutations in Chinese population remains incomplete at present. Therefore, the present study aimed to report specific harmful BRCA1/2 mutations in the Chinese population and discuss the clinicopathological features in mutation carriers. BRCA1/2 germline mutation tests for 71 patients with breast cancer from a hereditarily high-risk Chinese population were performed using next-generation sequencing for identification of deleterious mutations. Furthermore, the clinicopathological features between BRCA1/2 mutation carriers and non-carriers were compared. A total of 13/71 (18.3%) patients carried a BRCA1 or BRCA2 mutation (7 BRCA1 and 6 BRCA2). The incidence of BRCA1/2 mutation in patients with bilateral breast cancer and patients with family history were 25, and 32.2%, respectively. Eleven pathogenic or likely pathogenic mutations were identified in 13 patients, among the mutation sites 7 were never reported before in Asian populations. The age at diagnosis of BRCA1/2 mutation carriers was older compared with non-mutation carriers (44.73 vs. 35.39 years; P=0.001) in this cohort. BRCA1/2 deleterious mutation carriers had a significantly lower chance of human epidermal growth factor receptor-2 (Her-2) positive status (P=0.010), higher tumor grade at diagnosis (P=0.009), higher probability to have a family history (P=0.016) and older age at diagnosis. Estrogen receptor (ER) and progesterone receptor (PR) status were significantly different between BRCA1, and BRCA2 mutation carriers (P=0.007). The current interpretation of BRCA1/2 status can only explain a small part of hereditary high-risk breast cancer. However, BRCA1/2 gene testing should still be recommended for women with a family history of breast cancer, as well as patients with breast cancer with specific pathologic types, which may be useful to make appropriate clinical decisions for treatment and prevention.