Neural Functions Play Different Roles in Triple Negative Breast Cancer (TNBC) and non-TNBC

Network-based approach elucidates critical genes in BRCA subtypes and chemotherapy response in triple negative breast cancer

Breast cancers (BRCA) exhibit substantial transcriptional heterogeneity, posing a significant clinical challenge. The global transcriptional changes in a disease context, however, are likely mediated by few key genes which reflect disease etiology better than the differentially expressed genes (DEGs). We apply our network-based tool PathExt to 1,059 BRCA tumors across 4 subtypes to identify key mediator genes in each subtype. Compared to conventional differential expression analysis, PathExt-identified genes exhibit greater concordance across tumors, revealing shared and subtype-specific biological processes; better recapitulate BRCA-associated genes in multiple benchmarks, and are more essential in BRCA subtype-specific cell lines. Single-cell transcriptomic analysis reveals a subtype-specific distribution of PathExt-identified genes in multiple cell types from the tumor microenvironment. Application of PathExt to a TNBC chemotherapy response dataset identified subtype-specific key genes and biological processes associated with resistance. We described putative drugs that target key genes potentially mediating drug resistance.

Crosstalk between small-cell lung cancer cells and astrocytes mimics brain development to promote brain metastasis

Brain metastases represent an important clinical problem for patients with small-cell lung cancer (SCLC). However, the mechanisms underlying SCLC growth in the brain remain poorly understood. Here, using intracranial injections in mice and assembloids between SCLC aggregates and human cortical organoids in culture, we found that SCLC cells recruit reactive astrocytes to the tumour microenvironment. This crosstalk between SCLC cells and astrocytes drives the induction of gene expression programmes that are similar to those found during early brain development in neurons and astrocytes. Mechanistically, the brain development factor Reelin, secreted by SCLC cells, recruits astrocytes to brain metastases. These astrocytes in turn promote SCLC growth by secreting neuronal pro-survival factors such as SERPINE1. Thus, SCLC brain metastases grow by co-opting mechanisms involved in reciprocal neuron-astrocyte interactions during brain development. Targeting such developmental programmes activated in this cancer ecosystem may help prevent and treat brain metastases.

The tumor-nerve circuit in breast cancer

It is well established that innervation is one of the updated hallmarks of cancer and that psychological stress promotes the initiation and progression of cancer. The breast tumor environment includes not only fibroblasts, adipocytes, endothelial cells, and lymphocytes but also neurons, which is increasingly discovered important in breast cancer progression. Peripheral nerves, especially sympathetic, parasympathetic, and sensory nerves, have been reported to play important but different roles in breast cancer. However, their roles in the breast cancer progression and treatment are still controversial. In addition, the brain is one of the favorite sites of breast cancer metastasis. In this review, we first summarize the innervation of breast cancer and its mechanism in regulating cancer growth and metastasis. Next, we summarize the neural-related molecular markers in breast cancer diagnosis and treatment. In addition, we review drugs and emerging technologies used to block the interactions between nerves and breast cancer. Finally, we discuss future research directions in this field. In conclusion, the further research in breast cancer and its interactions with innervated neurons or neurotransmitters is promising in the clinical management of breast cancer.

Recent Advancement in Breast Cancer Research: Insights from Model Organisms-Mouse Models to Zebrafish

Animal models have been utilized for decades to investigate the causes of human diseases and provide platforms for testing novel therapies. Indeed, breakthrough advances in genetically engineered mouse (GEM) models and xenograft transplantation technologies have dramatically benefited in elucidating the mechanisms underlying the pathogenesis of multiple diseases, including cancer. The currently available GEM models have been employed to assess specific genetic changes that underlay many features of carcinogenesis, including variations in tumor cell proliferation, apoptosis, invasion, metastasis, angiogenesis, and drug resistance. In addition, mice models render it easier to locate tumor biomarkers for the recognition, prognosis, and surveillance of cancer progression and recurrence. Furthermore, the patient-derived xenograft (PDX) model, which involves the direct surgical transfer of fresh human tumor samples to immunodeficient mice, has contributed significantly to advancing the field of drug discovery and therapeutics. Here, we provide a synopsis of mouse and zebrafish models used in cancer research as well as an interdisciplinary 'Team Medicine' approach that has not only accelerated our understanding of varied aspects of carcinogenesis but has also been instrumental in developing novel therapeutic strategies.

Network-based approach elucidates critical genes in BRCA subtypes and chemotherapy response in Triple Negative Breast Cancer

Breast cancers exhibit substantial transcriptional heterogeneity, posing a significant challenge to the prediction of treatment response and prognostication of outcomes. Especially, translation of TNBC subtypes to the clinic remains a work in progress, in part because of a lack of clear transcriptional signatures distinguishing the subtypes. Our recent network-based approach, PathExt, demonstrates that global transcriptional changes in a disease context are likely mediated by a small number of key genes, and these mediators may better reflect functional or translationally relevant heterogeneity. We apply PathExt to 1059 BRCA tumors and 112 healthy control samples across 4 subtypes to identify frequent, key-mediator genes in each BRCA subtype. Compared to conventional differential expression analysis, PathExt-identified genes (1) exhibit greater concordance across tumors, revealing shared as well as BRCA subtype-specific biological processes, (2) better recapitulate BRCA-associated genes in multiple benchmarks, and (3) exhibit greater dependency scores in BRCA subtype-specific cancer cell lines. Single cell transcriptomes of BRCA subtype tumors reveal a subtype-specific distribution of PathExt-identified genes in multiple cell types from the tumor microenvironment. Application of PathExt to a TNBC chemotherapy response dataset identified TNBC subtype-specific key genes and biological processes associated with resistance. We described putative drugs that target top novel genes potentially mediating drug resistance. Overall, PathExt applied to breast cancer refines previous views of gene expression heterogeneity and identifies potential mediators of TNBC subtypes, including potential therapeutic targets.

The nerve growth factor-delivered signals in prostate cancer and its associated microenvironment: when the dialogue replaces the monologue

Prostate cancer (PC) represents the most diagnosed and the second most lethal cancer in men worldwide. Its development and progression occur in concert with alterations in the surrounding tumor microenvironment (TME), made up of stromal cells and extracellular matrix (ECM) that dynamically interact with epithelial PC cells affecting their growth and invasiveness. PC cells, in turn, can functionally sculpt the TME through the secretion of various factors, including neurotrophins. Among them, the nerve growth factor (NGF) that is released by both epithelial PC cells and carcinoma-associated fibroblasts (CAFs) triggers the activation of various intracellular signaling cascades, thereby promoting the acquisition of a metastatic phenotype. After many years of investigation, it is indeed well established that aberrations and/or derangement of NGF signaling are involved not only in neurological disorders, but also in the pathogenesis of human proliferative diseases, including PC. Another key feature of cancer progression is the nerve outgrowth in TME and the concept of nerve dependence related to perineural invasion is currently emerging. NGF released by cancer cells can be a driver of tumor neurogenesis and nerves infiltrated in TME release neurotransmitters, which might stimulate the growth and sustainment of tumor cells.In this review, we aim to provide a snapshot of NGF action in the interactions between TME, nerves and PC cells. Understanding the molecular basis of this dialogue might expand the arsenal of therapeutic strategies against this widespread disease.

Prediction and screening of circRNA in triple-negative breast cancer

OBJECTIVE

The purpose of this investigation was to study the expression profile and potential function of circular RNA (circRNA) and long noncoding RNA (lncRNA) in triple-negative breast cancer (TNBC).

METHODS

RNA sequencing technology was used to detect differentially expressed circRNAs and lncRNAs between TNBC tissues and the adjacent tissue. The potential functions of these different RNAs were analyzed by GO and KEGG enrichment analysis by bioinformatics tools. We also selected and analyzed these key circRNAs and lncRNAs to verify their important functions in TNBC.

RESULTS

A total of 139 differentially expressed circRNAs and 1001 lncRNAs were obtained. The co-expression analysis showed that the hub lncRNAs (OIP5-AS1, DRAIC) were associated with several tumors and mainly enriched in tumor metastasis. We also screened 5 circRNA-hosting genes (NTRK2, FNTA, BAPGEF2, MGST2, ADH1B) that were associated with the brain-derived neurotrophic factor (BDNF) receptor signaling pathway and cerebral cortex development, as well as AMPK and TGF-β signaling pathway.

CONCLUSION

We identified a large number of differentially expressed circRNAs and lncRNAs, which provide useful insight in understanding TNBC carcinogenesis.

Overexpression of GABRP Gene in Triple Negative Breast Cancer: Molecular Mechanisms and Interpretation

Background: Triple-negative breast cancer (TNBC) is a heterogeneous disease that characterized by aggressiveness features with increased metastasis and poor clinical prognosis. However, the molecular mechanisms underlying this highly malignant phenotype are still poorly understood. It has been well documented that the dysregulation of neural genes is profoundly implicated in cancer development and metastasis. Objectives: In the present study, the expression level of GABA receptor π subunit (GABRP) as the most up-regulated gene in TNBC and a hub node in the co-expression network were investigated. Methods: In this study, the importance of GABRP as the most up-regulated gene in TNBC was discovered through integrative analysis of multiple microarray expression datasets, containing about 1000 samples. Furthermore, the co-expression network analysis was constructed based on the up-regulated genes. Quantitative Real‐time polymerase chain reaction (qRT-PCR) was used to evaluate of the GABRP expression in 50 TNBC compared to 33 non-TNBC tumors. Results: According to the bioinformatics analysis, GABRP occupies a key position in the co-expression network which is mainly enriched in the nervous systems development. The qRT-PCR results indicated that up-regulation of GABRP was highly concordant with integrative analysis findings. Moreover, the receiver operating characteristic (ROC) curve analysis revealed that GABRP can be a potential biomarker to distinguish TNBC from non-TNBC samples. Conclusions: Our study revealed that up-regulation of GABRP is among the most remarkable molecular signature in TNBC and may play a critical role in tumorigenesis. The results may provide a deeper insight into molecular mechanisms underlying the brain metastasis in TNBC tumors and propose the potential targets for therapeutic interventions.

Ganglioside GD2: a novel therapeutic target in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a heterogeneous disease characterized by lack of hormone receptor expression and is known for high rates of recurrence, distant metastases, and poor clinical outcomes. TNBC cells lack targetable receptors; hence, there is an urgent need for targetable markers for the disease. Breast cancer stem-like cells (BCSCs) are a fraction of cells in primary tumors that are associated with tumorigenesis, metastasis, and resistance to chemotherapy. Targeting BCSCs is thus an effective strategy for preventing cancer metastatic spread and sensitizing tumors to chemotherapy. The CD44^hi CD24^lo phenotype is a well-established phenotype for identification of BCSCs, but CD44 and CD24 are not targetable markers owing to their expression in normal tissues. The ganglioside GD2 has been shown to be upregulated in primary TNBC tumors compared with normal breast tissue and has been shown to identify BCSCs. In this review, we discuss GD2 as a BCSC- and tumor-specific marker in TNBC; epithelial-to-mesenchymal transition and the signaling pathways that are upstream and downstream of GD2 and the role of these pathways in tumorigenesis and metastasis in TNBC; direct and indirect approaches for targeting GD2; and ongoing clinical trials and treatments directed against GD2 as well as future directions for these strategies.

Transcriptome Analysis Identifies GATA3-AS1 as a Long Noncoding RNA Associated with Resistance to Neoadjuvant Chemotherapy in Locally Advanced Breast Cancer Patients

Breast cancer is one of the leading causes of mortality in women worldwide, and neoadjuvant chemotherapy has emerged as an option for the management of locally advanced breast cancer. Extensive efforts have been made to identify new molecular markers to predict the response to neoadjuvant chemotherapy. Transcripts that do not encode proteins, termed long noncoding RNAs (lncRNAs), have been shown to display abnormal expression profiles in different types of cancer, but their role as biomarkers in response to neoadjuvant chemotherapy has not been extensively studied. Herein, lncRNA expression was profiled using RNA sequencing in biopsies from patients who subsequently showed either response or no response to treatment. The GATA3-AS1 transcript was overexpressed in the nonresponder group and was the most stable feature when performing selection in multiple random forest models. GATA3-AS1 was experimentally validated by RT-qPCR in an extended group of 68 patients. Expression analysis confirmed that GATA3-AS1 is overexpressed primarily in patients who were nonresponsive to neoadjuvant chemotherapy, with a sensitivity of 92.9%, a specificity of 75.0%, and an area under the curve of approximately 0.90, as measured by receiver operating characteristic curve analysis. The statistical model was based on luminal B-like patients and adjusted by menopausal status and phenotype (odds ratio, 37.49; 95% CI, 6.74-208.42; P = 0.001); GATA3-AS1 was established as an independent predictor of response. Thus, lncRNA GATA3-AS1 is proposed as a potential predictive biomarker of nonresponse to neoadjuvant chemotherapy.

Expression and Prognosis of Sperm-Associated Antigen 1 in Human Breast Cancer

Background

Sperm-associated antigen 1 (SPAG1) has been identified as a marker of pancreatic cancer progression and promoter of cell motility; however, its role in breast cancer is not completely understood.

Methods

SPAG1 expression in breast cancer tissues and normal tissues was obtained from online databases. Knockdown function assays were designed and conducted to verify the functional role of SPAG1 in breast cancer cell lines. Cell counting and MTT assays were used to assess cell proliferation. Cell flow cytometry assay was used for cell cycle phase arrest, and fluorescence microscopy was used for colony formation assessment.

Results

Both the mRNA and protein levels of SPAG1 were significantly higher in the breast cancer tissues than in the normal tissues. In addition, SPAG1 is significantly related to many clinicopathological features of breast cancer, such as age (>51 years), estrogen receptor (ER) (+), progesterone receptor (PR) (+), and nodal status (+), non-triple negative breast cancer (TNBC), not basal-like and not basal-like and not TNBC. Survival analysis indicates that breast cancer patients with low expression of SPAG1 had a significantly better prognosis with relapse-free survival (RFS). Functional experiment analysis revealed that knockdown of SPAG1 suppressed cell proliferation and colony-forming ability.

Conclusion

Our results suggested a possible role of SPAG1 in breast cancer pathogenesis.

Analysis of Cyclin-Dependent Kinase 1 as an Independent Prognostic Factor for Gastric Cancer Based on Statistical Methods

OBJECTIVE

The aim of this study was to investigate the expression of cyclin-dependent kinase 1 (CDK1) in gastric cancer (GC), evaluate its relationship with the clinicopathological features and prognosis of GC, and analyze the advantage of CDK1 as a potential independent prognostic factor for GC.

METHODS

The Cancer Genome Atlas (TCGA) data and corresponding clinical features of GC were collected. First, the aim gene was selected by combining five topological analysis methods, where the gene expression in paracancerous and GC tissues was analyzed by Limma package and Wilcox test. Second, the correlation between gene expression and clinical features was analyzed by logistic regression. Finally, the survival analysis was carried out by using the Kaplan-Meier. The gene prognostic value was evaluated by univariate and multivariate Cox analyses, and the gene potential biological function was explored by gene set enrichment analysis (GSEA).

RESULTS

CDK1 was selected as one of the most important genes associated with GC. The expression level of CDK1 in GC tissues was significantly higher than that in paracancerous tissues, which was significantly correlated with pathological stage and grade. The survival rate of the CDK1 high expression group was significantly lower than that of the low expression group. CDK1 expression was significantly correlated with overall survival (OS). CDK1 expression was mainly involved in prostate cancer, small cell lung cancer, and GC and was enriched in the WNT signaling pathway and T cell receptor signaling pathway.

CONCLUSION

CDK1 may serve as an independent prognostic factor for GC. It is also expected to be a new target for molecular targeted therapy of GC.