Short-term expansion of breast circulating cancer cells predicts response to anti-cancer therapy

Abstract

Circulating tumor cells (CTCs) are considered as surrogate markers for prognosticating and evaluating patient treatment responses. Here, 226 blood samples from 92 patients with breast cancer, including patients with newly diagnosed or metastatic refractory cancer, and 16 blood samples from healthy subjects were cultured in laser-ablated microwells. Clusters containing an increasing number of cytokeratin-positive (CK+) cells appeared after 2 weeks, while most blood cells disappeared with time. Cultures were heterogeneous and exhibited two distinct sub-populations of cells: ‘Small’ (≤ 25 μm; high nuclear/cytoplasmic ratio; CD45-) cells, comprising CTCs, and ‘Large’ (> 25 μm; low nuclear/cytoplasmic ratio; CD68+ or CD56+) cells, corresponding to macrophage and natural killer-like cells. The Small cell fraction also showed copy number increases in six target genes (FGFR1, Myc, CCND1, HER2, TOP2A and ZNF217) associated with breast cancer. These expanded CTCs exhibited different proportions of epithelial–mesenchymal phenotypes and were transferable for further expansion as spheroids in serum-free suspension or 3D cultures. Cluster formation was affected by the presence and duration of systemic therapy, and its persistence may reflect therapeutic resistance. This novel and advanced method estimates CTC clonal heterogeneity and can predict, within a relatively short time frame, patient responses to therapy.

Circulating tumor cell technologies

“…No RBC lysis required, captures viable cells, easy to manufacture, clusters observed (Sollier et al, 2014) ClearCell Ò FX RBC lysis required, 1e1.5 mL/min, captures viable cells, easy to manufacture (Khoo et al, 2015(Khoo et al, , 2014Warkiani et al, 2014) Biophysical e Electrophoresis Separates cells based on their electrical signature using an applied electric field. (Carpenter et al, 2014;Fabbri et al, 2013;Fernandez et al, 2014;Manaresi et al, 2003;Peeters et al, 2013;Polzer et al, 2014) Biophysical e Acoustophoresis Separates cells based on acoustophoretic mobility, which is size dependent, by exposing them to acoustic waves.…”

Circulating Tumor Cells and Circulating Tumor DNA: Challenges and Opportunities on the Path to Clinical Utility

“…Moreover, it remains unclear how many CTCs need to be analyzed to capture tumor heterogeneity sufficiently to predict treatment efficacy. lung cancers (59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70) and long-term cultures (6-24 months) of CTCs from patients with breast, prostate, and colorectal cancer (71)(72)(73)(74). The purpose of such model systems would be to study drug response or, in one study, to identify multilayer clusters, which if they appear in culture by day 14, may be an early predictor of therapy resistance (70).…”

The Landscape of Circulating Tumor Cell Research in the Context of Epithelial-Mesenchymal Transition

“…These findings remain in agreement with studies highlighting the importance of EMT in conferring chemoresistance in BC and pancreatic cancer models [22,153] . Recently, short-term expansion of CTCs in microwell-based culture was reported to predict response to anticancer therapy in early-stage, locally advanced and MBC [154] . Cluster formation in cell culture was affected by the presence and duration of systemic therapy, and its persistence may reflect therapeutic resistance as it correlated with shorter OS [154] .…”

“…Recently, short-term expansion of CTCs in microwell-based culture was reported to predict response to anticancer therapy in early-stage, locally advanced and MBC [154] . Cluster formation in cell culture was affected by the presence and duration of systemic therapy, and its persistence may reflect therapeutic resistance as it correlated with shorter OS [154] . Also gene expression profiles in CTCs were reported to predict response to therapy with aromatase inhibitors [155] and during the course of palliative treatment in MBC [156] .…”