Background Common sites of distant metastases from BC include the skeleton and a number of studies have long attempted to identify a specific osteotropism signature to select patients for preventive therapeutic options. Here, we evaluated the expression of a gene panel potentially involved in BM onset in CTCs from metastatic BC patients and found a putative correlation of such a gene profile with sites of distant relapse. Methods Following approval by local Ethics Committee and written informed consent, CTCs were isolated from 39 stage IV BC patients, either treatment naïve or in progressive disease, through immunomagnetic pre-enrichment with autoMACS Separator® and sorting by DEPArray®. A panel of 136 genes involved in BC progression and BM development was derived from literature data to assess their expression levels in CTCs by RNAseq. The panel was first verified on subclones of the MDA-MB231 BC cell line with different organotropism (P0:parental population; P7:osteotropic subclone; LM:subclone with lung tropism) and then validated in CTCs from patients grouped in relation to their metastatic sites, namely (a) BM-only, (b) Other, (c) BM and Other, at the time of collection. Results The median number of recovered CTCs was 56 (range 9–106). No correlation was found between CTC number and BC histopathological features. The transcriptome heatmap of unsupervised hierarchical clustering of BC cell lines, based on normalized read counts, clustered distinct profiles in relation to their tissue tropism. The feasibility of this approach was then validated on CTCs and 31 differentially expressed genes (DEGs) were revealed between CTCs from (a) and (b) groups. By Gene Ontology evaluation of these DEGs, we found that most of them were enriched with greater statistical significance in different biological processes enrolled in bone tissue development and morphogenesis. Conclusions CTCs isolated from BC patients with different sites of metastases harbor distinct GEP that can be successfully evaluated by our assay. Prospective investigation is desirable to assess the prognostic role of identified DEGs in earlier BC stages.
In search of a bone metastasis (BM) gene signature in circulating tumour cells (CTCs) from stage IV breast cancer (BC) patients
D'Oronzo S;Lovero D;Palmirotta R;Cafforio P;Cives M;Tucci M;Silvestris F.
2020-01-01
Abstract
Background Common sites of distant metastases from BC include the skeleton and a number of studies have long attempted to identify a specific osteotropism signature to select patients for preventive therapeutic options. Here, we evaluated the expression of a gene panel potentially involved in BM onset in CTCs from metastatic BC patients and found a putative correlation of such a gene profile with sites of distant relapse. Methods Following approval by local Ethics Committee and written informed consent, CTCs were isolated from 39 stage IV BC patients, either treatment naïve or in progressive disease, through immunomagnetic pre-enrichment with autoMACS Separator® and sorting by DEPArray®. A panel of 136 genes involved in BC progression and BM development was derived from literature data to assess their expression levels in CTCs by RNAseq. The panel was first verified on subclones of the MDA-MB231 BC cell line with different organotropism (P0:parental population; P7:osteotropic subclone; LM:subclone with lung tropism) and then validated in CTCs from patients grouped in relation to their metastatic sites, namely (a) BM-only, (b) Other, (c) BM and Other, at the time of collection. Results The median number of recovered CTCs was 56 (range 9–106). No correlation was found between CTC number and BC histopathological features. The transcriptome heatmap of unsupervised hierarchical clustering of BC cell lines, based on normalized read counts, clustered distinct profiles in relation to their tissue tropism. The feasibility of this approach was then validated on CTCs and 31 differentially expressed genes (DEGs) were revealed between CTCs from (a) and (b) groups. By Gene Ontology evaluation of these DEGs, we found that most of them were enriched with greater statistical significance in different biological processes enrolled in bone tissue development and morphogenesis. Conclusions CTCs isolated from BC patients with different sites of metastases harbor distinct GEP that can be successfully evaluated by our assay. Prospective investigation is desirable to assess the prognostic role of identified DEGs in earlier BC stages.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
