STIM1, ORAI1, and KDM2B in circulating tumor cells (CTCs) isolated from prostate cancer patients

Introduction: Previous publications have shown that STIM1, ORAI1, and KDM2B, are implicated in Ca2+ signaling and are highly expressed in various cancer subtypes including prostate cancer. They play multiple roles in cancer cell migration, invasion, and metastasis. In the current study we investigated the expression of the above biomarkers in circulating tumor cells from patients with metastatic prostate cancer.Methods: Thirty-two patients were enrolled in this study and CTCs’ isolation was performed with Ficoll density gradient. Two different triple immunofluorescence stainings were conducted with the following combination of antibodies: CK/KDM2B/CD45 and CK/STIM1/ORAI1. Slides were analyzed using VyCAP microscopy technology.Results: CTC-positive patients were detected in 41% for (CK/KDM2B/CD45) staining and in 56% for (CK/STIM1/ORAI1) staining. The (CK+/KDM2B+/CD45–) and the (CK+/STIM1+/ORAI1+) were the most frequent phenotypes as they were detected in 85% and 94% of the CTC-positive patients, respectively. Furthermore, the expression of ORAI1 and STIM1 in patients’ PBMCs was very low exhibiting them as interesting specific biomarkers for CTC detection. The (CK+/STIM1+/ORAI1+) phenotype was correlated to bone metastasis (p = 0.034), while the (CK+/STIM1+/ORAI1–) to disease relapse (p = 0.049).Discussion: STIM1, ORAI1, and KDM2B were overexpressed in CTCs from patients with metastatic prostate cancer. STIM1 and ORAI1 expression was related to disease recurrence and bone metastasis. Further investigation of these biomarkers in a larger cohort of patients will clarify their clinical significance for prostate cancer patients

Clinical Relevance of Mesenchymal- and Stem-Associated Phenotypes in Circulating Tumor Cells Isolated from Lung Cancer Patients

Lung cancer is the leading cause of cancer-related mortality globally. Among the types of lung cancer, non-small-cell lung cancer (NSCLC) is more common, while small-cell lung cancer (SCLC) is less frequent yet more aggressive. Circulating tumor cells (CTCs), albeit rare, have been portrayed as essential players in the progression of lung cancer. CTCs are considered to adopt an epithelial-to-mesenchymal transition (EMT) phenotype and characteristics of cancer stem cells (CSCs). This EMT (or partial) phenotype affords these cells the ability to escape from the primary tumor, travel into the bloodstream, and survive extremely adverse conditions, before colonizing distant foci. Acquisition of CSC features, such as self-renewal, differentiation, and migratory potential, further reflect CTCs’ invasive potential. CSCs have been identified in lung cancer, and expression of EMT markers has previously been correlated with poor clinical outcomes. Thus far, a vast majority of studies have concentrated on CTC detection and enumeration as a prognostic tools of patients’ survival or for monitoring treatment efficacy. In this review, we highlight EMT and CSC markers in CTCs and focus on the clinical significance of these phenotypes in the progression of both non-small- and small-cell lung cancer

Evaluation of Isolation Methods for Circulating Tumor Cells (CTCs)

Background: Detection of CTCs is a poor prognostic factor for many cancer types; however, their very low frequency represents an obstacle for their detection. The objective of the current study was to compare the performance of commonly used methods for CTCs isolation. Methods: The evaluated methods using spiking experiments of MCF7, SKBR3 and MDA MB-231 breast cancer cell lines were (i) ficoll density gradient separation (DGS), (ii) red blood cell lysis (Erythrolysis) isolation, (iii) positive immunomagnetic selection (EpCAM Dynal beads), (iv) two different negative immunomagnetic separation systems (Dynal vs Miltenyi CD45 beads) as well as (v) the Cell Search platform and (vi) the ISET system. Results: The recovery rates of Erythrolysis and DGS were 39% and 24%, respectively. Magnetic isolations are ranked from the worse to the best recovery rate as follows:, Myltenyi-anti-CD45 microbeads (24%); Dynal-anti-EpCAM beads (75%); Dynabeads-anti-CD45 (97%). CTCs isolation from blood samples using the CellSearch and ISET systems revealed that the recovery rate for Cell Search and ISET was 52% and 95%, respectively. Conclusions: Dynal-anti-CD45 beads have the best recovery rate compared to other magnetic methods. Furthermore the recovery rate of ISET was higher compared to Cell Search, especially for the more aggressive MDA-MB 231 cell line