Incremental increase in VEGFR1+ hematopoietic progenitor cells and VEGFR2+ endothelial progenitor cells predicts relapse and lack of tumor response in breast cancer patients

Abstract

Purpose Animal models have demonstrated the critical role of bone marrow-derived VEGFR1+ hematopoietic progenitor cells (HPCs) and VEGFR2+ endothelial progenitor cells (EPCs) in metastatic progression. We explored whether these cells could predict relapse and response in breast cancer (BC) patients. Experimental Design 132 patients with stages 1 to 4 BC were enrolled on 2 studies. Circulating CD45+/CD34+/VEGFR1+ HPCs and CD45dim/CD133+/VEGFR2+ EPCs were assessed from peripheral blood mononuclear cells using flow cytometry. Changes in HPCs and EPCs were analyzed in 1) patients without overt disease that relapsed and 2) metastatic patients according to response by RECIST. Results At study entry, 102 patients were without evidence of disease and 30 patients had metastatic BC. Seven patients without evidence of BC by exam, labs, and imaging developed recurrence while on study. Median HPC/mL (range) increased from 645.8 (23.5-1914), p=0.016, followed by an increase in median EPC/mL from 21.3 (4.7-42.5) to 94.7 (28.2-201.3), p=0.016, prior to clinical relapse. In metastatic patients with progressive disease, median HPC/mL increased from 1696 (10-16470) to 5124 (374-77605), p=0.0009, and median EPC/mL increased from 26 (0-560) to 71 (0-615) prior to progression, p=0.10. In patients with responding disease, median HPC/mL decreased from 6147 (912-85070) to 633 (47-18065), p=0.05, and EPC/mL decreased from 46 (0-197) to 23 (0-105), p=0.41, at response. There were no significant changes in these cells over time in patients with stable disease. Conclusions Circulating bone marrow-derived HPCs and EPCs predict relapse and disease progression in BC patients.

Influencing the Tumor Microenvironment: A Phase II Study of Copper Depletion Using Tetrathiomolybdate in Patients with Breast Cancer at High Risk for Recurrence and in Preclinical Models of Lung Metastases

“…Furthermore, we have demonstrated, in a large cohort of patients with breast cancer, that this model of metastatic progression recapitulates the preclinical models (10).…”

“…To quantitate HPCs, cells were stained with CD34-FITC (BD Biosciences), VEGFR1-APC (R&D Systems), and CD45-PerCP (BD Biosciences). Multicolor flow cytometry was performed as described previously (10).…”

Tetrathiomolybdate-associated copper depletion decreases circulating endothelial progenitor cells in women with breast cancer at high risk of relapse

“…Moreover, these findings suggest that TM may have direct effects on the tumor microenvironment at the level of the bone marrow niche, the sanctuary site for EPCs. Though HPCs did not significantly change in patients receiving TM, our previous studies showed that HPCs predicted relapse and progression of disease, suggesting that these cells may also be important in the metastatic cascade, but upstream of the processes was affected by copper depletion [14].…”

“…Flow cytometry was carried out as previously described [14]. Plasma SDF-1 was detected by enzyme-linked immunosorbent assay (R & D Systems, Minneapolis, MN) and c-kit, VEGFR2, and matrix metalloproteinases (MMP)-1, -3, and -9 by multiplex assays (Meso Scale Discovery, Gaithersburg, MD) as per manufacturer's protocol.…”

“…EPC deficiency results in impaired macrometastatic formation as a result of severe angiogenesis inhibition [9]. We extended these analyses to breast cancer patients, in which significant increases in EPCs and HPCs were observed immediately before overt relapse, suggesting that these cells comprise a critical component for the propagation of macrometastases [14].…”