The prognostic value of JUNB-positive CTCs in metastatic breast cancer: from bioinformatics to phenotypic characterization

Abstract

Background Circulating tumor cells (CTCs) are important for metastatic dissemination of cancer. They can provide useful information, regarding biological features and tumor heterogeneity; however, their detection and characterization are difficult due to their limited number in the bloodstream and their mesenchymal characteristics. Therefore, new biomarkers are needed to address these questions. Methods Bioinformatics functional enrichment analysis revealed a subgroup of 24 genes, potentially overexpressed in CTCs. Among these genes, the chemokine receptor CXCR4 plays a central role. After prioritization according to the CXCR4 corresponding pathways, five molecules (JUNB, YWHAB, TYROBP, NFYA, and PRDX1) were selected for further analysis in biological samples. The SKBR3, MDA-MB231, and MCF7 cell lines, as well as PBMCs from normal ( n = 10) blood donors, were used as controls to define the expression pattern of all the examined molecules. Consequently, 100 previously untreated metastatic breast cancer (mBC) patients ( n = 100) were analyzed using the following combinations of antibodies: CK (cytokeratin)/CXCR4/JUNB, CK/NFYA/ΥWHΑΒ (14-3-3), and CK/TYROBP/PRDX1. A threshold value for every molecule was considered the mean expression in normal PBMCs. Results Quantification of CXCR4 revealed overexpression of the receptor in SKBR3 and in CTCs, following the subsequent scale (SKBR3>CTCs>Hela>MCF7>MDA-MB231). JUNB was also overexpressed in CTCs (SKBR3>CTCs>MCF7>MDA-MB231>Hela). According to the defined threshold for each molecule, CXCR4-positive CTCs were identified in 90% of the patients with detectable tumor cells in their blood. In addition, 65%, 75%, 14.3%, and 12.5% of the patients harbored JUNB-, TYROBP-, NFYA-, and PRDX-positive CTCs, respectively. Conversely, none of the patients revealed YWHAB-positive CTCs. Interestingly, JUNB expression in CTCs was phenotypically and statistically enhanced compared to patients’ blood cells ( p = 0.002) providing a possible new biomarker for CTCs. Furthermore, the detection of JUNB-positive CTCs in patients was associated with poorer PFS ( p = 0.015) and OS ( p = 0.002). Moreover, JUNB staining of 11 primary and 4 metastatic tumors from the same cohort of patients revealed a dramatic increase of JUNB expression in metastasis. Conclusions CXCR4, JUNB, and TYROBP were overexpressed in CTCs, but only the expression of JUNB was associated with poor prognosis, providing a new biomarker and a potential therapeutic target for the elimination of CTCs. Electronic supplementary material The online version of this article (10.1186/s13058-019-1166-4) contains supplementary material, which is available to authorized users.

Resolving an underrepresented circulating tumor cell population in lung cancer enabled by Hexokinase 2 analysis

“…Consistently, in CK low cells of the mesenchymal population, we also found increased expression of LOX and JUNB, which have been implicated in enhanced invasiveness and tumor metastasis (31)(32)(33).…”

New insights in gene expression alteration as effect of doxorubicin drug resistance in triple negative breast cancer cells

“…Other gene found in drug resistance network is JUNB which has been associated with invasion/metastasis in breast cancer and represents an important target in diseases, associated with EMT. Also, JUNB has been involved in the earliest events of resistance development in breast cancer [36]. In addition, CLU (Clusterin) is involved in anti-apoptotic processes, development of therapy resistance, induction of EMT, all associated with cancer metastasis.…”

Prognostic genes in the tumor microenvironment in cervical squamous cell carcinoma

“…In this study, ITGAM, ITGAX, TYEOBP, and C3AR1 were not associated with overall survival. ITGAM and ITGAX are mainly involved in systemic lupus erythematosus [23, 24], while TYEOBP and C3AR1 have been studied in the context of breast cancer [25, 26]. To the best of our knowledge, however, no association between these four genes and CSCC has been reported until now.…”