Abstract Hormone-responsive breast cancer represents the most common type and has the best prognosis, but still approximately 40% of patients with this type can develop distant metastases, ...dramatically worsening the patient’s survival. Monitoring metastatic breast cancer (mBC) for signs of progression is an important part of disease management. Circulating tumor cell (CTC) detection and molecular characteristics gain importance as a diagnostic tool, but do not represent a clinical standard and its value as a predictor of progression is not yet established. The main objective of this study was to estimate the prognostic value of not only the CTC numbers, but also the dynamics of the CTC numbers in the same patient during the continuous evaluation of CTCs in patients with advanced breast cancer. The other objective was to assess the molecular changes in CTCs compared to primary tumor samples by genetic analysis of the seven genes associated with estrogen signaling pathway, mutations in which are often responsible for the resistance to endocrine therapy, and subsequent progression. This approach was taken to evaluate if genetic analysis of CTCs can be used in tracking the resistance, signaling that hormonal therapy should be replaced. Consequently, this report presents the results of a longitudinal CTC study based on three subsequent blood collections from 135 patients with metastatic breast cancer, followed by molecular analysis of the isolated single CTCs. CTCs were detected and isolated using an image-based, EpCAM-independent system CytoTrack; this approach allowed evaluation of EpCAM expression in detected CTCs. Isolated CTCs were subjected to NGS analysis to assess mutational changes. The results confirm the importance of the status of the CTC for progression-free survival and overall survival and provide new data on the dynamics of the CTC during a long monitoring period and in relation to clinical progression, highlighting the advantage of constant monitoring over the single count of CTC. Furthermore, high genetic and phenotypic inter- and intrapatient heterogeneity observed in CTCs suggest that metastatic lesions are divergent. High genetic heterogeneity in the matching CTC/primary tumor samples may indicate early dissemination. The tendency towards the accumulation of activating/oncogenic mutation in CTCs, leading to anti-estrogen resistant disease, was not confirmed in this study.
Circulating tumor cells (CTCs) are gaining momentum as a diagnostic tool and therapeutic target. CTC clusters are more metastatic, but harder to study and characterize, because they are rare and the ...methods of isolation are mostly focused on single CTCs. This review highlights the recent advances to our understanding of tumor cell clusters with the emphasis on their composition, origin, biology, methods of detection, and impact on metastasis and survival. New approaches to therapy, based on cluster characteristics are also described.
HAX1 is a human protein with no known homologues or structural domains. Mutations in the HAX1 gene cause severe congenital neutropenia through mechanisms that are poorly understood. Previous studies ...reported the RNA-binding capacity of HAX1, but the role of this binding in physiology and pathology remains unexplained. Here, we report the transcriptome-wide characterization of HAX1 RNA targets using RIP-seq and CRAC, indicating that HAX1 binds transcripts involved in translation, ribosome biogenesis, and rRNA processing. Using CRISPR knockouts, we find that HAX1 RNA targets partially overlap with transcripts downregulated in HAX1 KO, implying a role in mRNA stabilization. Gene ontology analysis demonstrated that genes differentially expressed in HAX1 KO (including genes involved in ribosome biogenesis and translation) are also enriched in a subset of genes whose expression correlates with HAX1 expression in four analyzed neoplasms. The functional connection to ribosome biogenesis was also demonstrated by gradient sedimentation ribosome profiles, which revealed differences in the small subunit:monosome ratio in HAX1 WT/KO. We speculate that changes in HAX1 expression may be important for the etiology of HAX1-linked diseases through dysregulation of translation.
•BCL-XL, but not HAX-1, prevents apoptosis following cytokine deprivation.•HAX-1 fails to influence BAX-induced apoptosis in HeLa carcinoma cells.•HAX-1 reduces thapsigargin-triggered apoptosis in ...murine bone marrow cells.•HAX-1 plays a cell type- and stimulus-specific role in regulation of cell survival.
HS-1-associated protein X-1 (HAX-1) is a multi-functional protein that has been implicated in the regulation of apoptosis, cell motility and calcium homeostasis. In the present study, we set out to assess the postulated functional resemblance of HAX-1 to the BCL-2 family of anti-apoptotic proteins using non-transformed, cytokine-dependent murine bone marrow cells as a model system. BCL-XL, but not HAX-1 protected against cytokine withdrawal-induced apoptosis while HAX-1 and BCL-XL significantly reduced thapsigargin-triggered (calcium-dependent) apoptosis. The data argue in favor of cell type- and stimulus-specific roles of HAX-1 in regulation of cell survival.
HAX1 is an antiapoptotic factor involved in the regulation of cell migration and calcium homeostasis, overexpressed in several cancers, including breast cancer. It has been suggested that HAX1 is ...also implicated in metastasis. Herein we report the results of meta-analysis of HAX1 expression, based on publicly available data, which confirms its significant overexpression in breast cancer and demonstrates copy number gain and prognostic value of HAX1 overexpression for metastatic relapse in ER+ tumors. IHC analysis reported here also reveals its significant overexpression in breast cancer samples from primary tumors, indicating significantly higher HAX1 protein levels in a group of patients who developed distant metastases in a disease course. Moreover, we demonstrate that HAX1 localization is important for the prediction of metastatic relapse and that cytoplasmic but not nuclear HAX1 is an independent risk factor for breast cancer metastasis.
Angiogenesis is a necessary step in tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is a major mediator of breast cancer angiogenesis. Therefore, we investigated the ...association of polymorphisms in the VEGF gene with breast cancer risk and prognostic characteristics of the tumors in a large case-control study.
We examined three polymorphisms in the VEGF gene (-2578C/A, -1154G/A, and +936C/T) in 571 familial breast cancer cases from Poland and Germany and -2578C/A, -634G/C, and +936C/T polymorphisms in 974 unselected breast cancer cases from Sweden together with ethnically and geographically selected controls.
None of the polymorphisms or any haplotype was significantly associated with either familial or unselected breast cancers. Our study suggests that the +936C/T polymorphism is unlikely to be associated with breast cancer. We also analyzed the unselected cases for genotypes or haplotypes that associated with tumor characteristics. The -634CC genotype and the -2578/-634 CC haplotype were significantly associated with high tumor aggressiveness (large tumor size and high histologic grade, P < 0.01) and the -2578AA genotype and the -2578/-634 AG haplotype with low histologic grade tumors (P = 0.04). The genotypes and haplotypes were not related with other tumor characteristics such as regional or distant metastasis, stage at diagnosis, or estrogen or progesterone receptor status.
Although none of the polymorphisms studied in the VEGF gene was found to influence susceptibility to breast cancer significantly, some of the VEGF genotypes and haplotypes may influence tumor growth through an altered expression of VEGF and tumor angiogenesis.
Tumor protein 53 (
) is a tumor suppressor gene that encodes tumor protein p53. Tumor protein p53 regulates the expression of target genes in response to cellular stress. Additionally, p53 ...participates in the regulation of cell cycle checkpoints, DNA repair and apoptosis. Mutations in the
gene are associated with numerous types of human cancer, including breast cancer, sarcomas, brain tumors and adrenal cortical carcinomas. In breast cancer,
mutations are a negative prognostic factor. Tumors with
mutations are more likely to be aggressive (triple-negative or human epidermal growth factor receptor 2-positive breast cancer), and resistant to chemotherapy and radiotherapy. In addition to a well-known
mutation, a number of single nucleotide polymorphisms have been systematically identified and evaluated in human populations. In the present article, the role of
mutations and polymorphisms in clinical practice and breast cancer treatment has been described. Additionally, the existing data on
polymorphisms in breast cancer as prognostic and predictive factors have been summarized. A literature search of these topics was performed through PubMed and abstracts of the main cancer congresses in recent years.
HAX‐1 is a multi‐functional protein that is involved in the regulation of apoptosis, cell motility and calcium homeostasis. It is also reported to bind RNA: it associates with structural motifs ...present in the 3′ untranslated regions of at least two transcripts, but the functional significance of this binding remains unknown. Although HAX‐1 has been detected in various cellular compartments, it is predominantly cytoplasmic. Our detailed localization studies of HAX‐1 isoforms revealed partial nuclear localization, the extent of which depends on the protein isoform. Further studies demonstrated that HAX‐1 is in fact a nucleocytoplasmic shuttling protein, dependent on the exportin 1 nuclear export receptor. Systematic mutagenesis allowed identification of the two nuclear export signals in the HAX‐1 sequence. HAX‐1 nuclear accumulation was observed after inhibition of nuclear export by leptomycin B, but also after specific cellular stress. The biological role of HAX‐1 nuclear localization and shuttling remains to be established, but the HAX‐1 transcript‐binding properties suggest that it may be connected to mRNA processing and surveillance. In this study, HAX‐1 status was shown to influence mRNA levels of DNA polymerase β, one of the HAX‐1 mRNA targets, although this effect becomes pronounced only after specific stress is applied. Moreover, HAX‐1 tethering to the reporter transcript caused a significant decrease in its expression. Additionally, the HAX‐1 co‐localization with P‐body markers, reported here, implies a role in mRNA processing. These results suggest that HAX‐1 may be involved in the regulation of expression of bound transcripts, possibly as part of the stress response.
Structured digital
HAX1 and DCP1A, colocalize by fluorescence microscopy (View Interaction: 1, 2)
HAX1 physically interacts with XPO1 by anti tagcoimmunoprecipitation (View interaction)
Multifunctional HAX‐1 protein is known to bind mRNA, but the functional significance of this binding remains unknown. In here we report XPO1‐dependent nuclear shuttling of HAX‐1 and the identification of its nuclear export signals. Moreover, we demonstrated HAX‐1 influence on mRNA processing of the bound transcripts and its co‐localization with processing bodies
Altered DNA methylation is often seen in malignant cells, potentially contributing to carcinogenesis by suppressing gene expression. We hypothesized that heritable methylation potential might be a ...risk factor for breast cancer and evaluated possible association with breast cancer for single nucleotide polymorphisms (SNPs) either involving CpG sequences in extended 5′‐regulatory regions of candidate genes (ESR1, ESR2, PGR, and SHBG) or CpG and missense coding SNPs in genes involved in methylation (MBD1, MECP2, DNMT1, MGMT, MTHFR, MTR, MTRR, MTHFD1, MTHFD2, BHMT, DCTD, and SLC19A1). Genome‐wide searches for genetic risk factors for breast cancers have in general not investigated these SNPs, because of low minor allele frequency or weak haplotype associations. Genotyping was performed using Mass spectrometry‐Maldi‐Tof in a screening panel of 538 cases and 1,067 controls. Potential association to breast cancer was identified for 15 SNPs and one of these SNPs (rs7766585 in ESR1) was found to associate strongly with breast cancer, OR 1.30 (95% CI 1.17–1.45; p‐value 2.1 × 10−6), when tested in a verification panel consisting of 3,211 unique breast cancer cases and 4,223 unique controls from five European biobank cohorts. In conclusion, a candidate gene search strategy focusing on methylation‐related SNPs did identify a SNP that associated with breast cancer at high significance.
HAX-1: a novel p-body protein Zayat, Valery; Balcerak, Anna; Korczynski, Jaroslaw ...
DNA and cell biology
34, Številka:
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Journal Article
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HAX-1, a multifunctional protein involved in the regulation of apoptosis, cell migration, and calcium homeostasis, binds the 3' untranslated region motifs of specific transcripts. This suggests that ...HAX-1 plays a role in post-transcriptional regulation, at the level of mRNA stability/transport or translation. In this study, we analyze in detail HAX-1 colocalization with processing bodies (P-bodies) and its dependence on mRNA availability. Endogenous P-body markers DCP1 and Rck/p54 were shown to colocalize with endogenous HAX-1, but in case of the overexpressed proteins, only DCP1 displayed unperturbed colocalization with HAX-1. HAX-1 colocalization with DCP1 was observed in most of the cell lines studied, but its presence was not required for P-body formation, and its silencing caused an increase in P-body number. Preliminary mapping suggested that HAX-1 has more than one short P-body-targeting sequence. The pools of P-body-localized HAX-1 and cytosolic HAX-1 were demonstrated to dynamically exchange, suggesting steady flow of the protein. Active transcription was shown to be a factor in the localization of HAX-1 to P-bodies. Also, it was observed that HAX-1 localizes to some unidentified foci, which do not contain DCP1. In addition, it was demonstrated that HAX-1 status influences vimentin expression levels. Overall, HAX-1 was shown to colocalize with P-body markers and influence P-body number per cell in a manner dependent on mRNA availability. Presented data support the hypothesis that HAX-1 is involved in mRNA processing as an element of P-body interaction network.
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