Isolation and transplantation of highly purified autologous peripheral CD34+ progenitor cells: purging efficacy, hematopoietic reconstitution following high dose chemotherapy in patients with breast cancer: results of a feasibility study in Japan

Cancer stem cell labeling using poly(L-lysine)-modified iron oxide nanoparticles

Cell labeling using magnetic nanoparticles is an increasingly used approach in noninvasive behavior tracking, in vitro separation of cancer stem cells (CSCs), and CSC-based research in cancer therapy. However, the impact of magnetic labeling on the biological properties of targeted CSCs, such as self-renewal, proliferation, multi-differentiation, cell cycle, and apoptosis, remains elusive. The present study sought to explore the potential effects on biological behavior when CSCs are labeled with superparamagnetic iron oxide (SPIO) nanoparticles in vitro. The glioblastoma CSCs derived from U251 glioblastoma multiforme were labeled with poly(L-lysine) (PLL)-modified γ-Fe(2)O(3) nanoparticles. The iron uptake of glioblastoma CSCs was confirmed through prussian blue staining, and was further quantified using atomic absorption spectrometry. The cellular viability of the SPIO-labeled glioblastoma CSCs was assessed using a fluorescein diacetate and propidium iodide double-staining protocol. The expressed specific markers and multi-differentiation of SPIO-labeled glioblastoma CSCs were comparatively assessed by immunocytochemistry and semi-quantitative RT-PCR. The effects of magnetic labeling on cell cycle and apoptosis rate of glioblastoma CSCs and their differentiated progenies were assayed using a flow cytometer. The results demonstrated that the cell viability and proliferation capacity of glioblastoma CSCs and their differentiated progenies were not affected by SPIO labeling compared with their unlabeled counterparts. Moreover, the magnetically labeled CSCs displayed an intact multi-differentiation potential, and could be sub-cultured to form new tumor spheres, which indicates the CSCs capacity for self-renewal. In addition, cell cycle distribution, apoptosis rate of the magnetically labeled glioblastoma CSCs, and their differentiated progenies were not impaired. Therefore, the SPIO-labeled CSCs could be a feasible approach in conducting further functional analysis of targeted CSCs.

Enrichment of circulating tumor cells from a large blood volume using leukapheresis and elutriation: proof of concept

BACKGROUND

The aim of this study was to determine the applicability of a sequential process using leukapheresis, elutriation, and fluorescence-activated cell sorting (FACS) to enrich and isolate circulating tumor cells from a large blood volume to allow further molecular analysis.

METHODS

Mononuclear cells were collected from 10 L of blood by leukapheresis, to which carboxyfluorescein succinimidyl ester prelabeled CaOV-3 tumor cells were spiked at a ratio of 26 to 10⁶ leukocytes. Elutriation separated the spiked leukapheresates primarily by cell size into distinct fractions, and leukocytes and tumor cells, characterized as carboxyfluorescein succinimidyl ester positive, EpCAM positive and CD45 negative events, were quantified by flow cytometry. Tumor cells were isolated from the last fraction using FACS or anti-EpCAM coupled immunomagnetic beads, and their recovery and purity determined by fluorescent microscopy and real-time PCR.

RESULTS

Leukapheresis collected 13.5 x 10⁹ mononuclear cells with 87% efficiency. In total, 53 to 78% of spiked tumor cells were pre-enriched in the last elutriation fraction among 1.6 x 10⁹ monocytes. Flow cytometry predicted a circulating tumor cell purity of ~90% giving an enrichment of 100,000-fold following leukapheresis, elutriation, and FACS, where CaOV-3 cells were identified as EpCAM positive and CD45 negative events. FACS confirmed this purity. Alternatively, immunomagnetic bead adsorption recovered 10% of tumor cells with a median purity of 3.5%.

CONCLUSIONS

This proof of concept study demonstrated that elutriation and FACS following leukapheresis are able to enrich and isolate tumor cells from a large blood volume for molecular characterization.

CD34(+) hematopoietic progenitor cell selection of bone marrow grafts for autologous transplantation in pediatric patients

CD34(+)-selection of hematopoietic grafts for patients undergoing autologous hematopoietic stem cell transplantation (HSCT) is frequently used to obtain a tumor-free graft. The majority of published experience is with peripheral blood stem cell (PBSC) products; only scant information has been published on bone marrow (BM) grafts. We reviewed our experience using CD34(+) selection of BM grafts in children undergoing autologous BM transplantation. After obtaining institutional approval, we performed a retrospective review of the medical records of patients who underwent autologous stem cell collection at St. Jude. From January 1, 1999, to December 31, 2003, 373 patients underwent autologous HSCT; 131 received marrow grafts, 237 received PBSC grafts, and 5 received a combination. Seventeen patients underwent BM harvests for CD34(+) selection of their stem cell grafts. Sixteen patients received 19 CD34 purified grafts processed on the Isolex 300i Magnetic Cell Selection System device. Four patients were not included in the engraftment analysis as 1 did not receive the collected product, 1 received a tandem product, and 2 received products that were composed of 2 or 3 combined purified products. Following selection, marrow grafts contained a median of 1.4 x 10(6) CD34(+) cells/kg (range: 0.09-8.3 x 10(6)/kg) and a median of 0.014 x10(8) total nucleated cell cells/kg (range: 0.001-0.09 x 10(8)/kg). The median CD34% recovery was 30.9% (range: 9.3%-57.1%), with the median CD34 purity being 95.5% (range: 62.2%-98.8%). All patients engrafted. The median time to absolute neutrophil count > or = 500/mm(3) was 19 days (range: 12-35 days), and to platelet recovery was 28 days (range 18-37 days). No patient died from transplant-related complications. Our study demonstrates that CD34(+)-selection of marrow grafts is feasible, and these grafts are able to successfully reconstitute hematopoiesis in patients undergoing autologous BMT.

Malignant Pheochromocytomas and Paragangliomas: A Phase II Study of Therapy with High-Dose 131I-Metaiodobenzylguanidine (131I-MIBG)

Thirty patients with malignant pheochromocytoma (PHEO) or paraganglioma (PGL) were treated with high-dose 131I-MIBG. Patients were 11-62 (mean 39) years old: 19 patients males and 11 females. Nineteen patients had PGL, three of which were multifocal. Six PGLs were nonsecretory. Eleven patients had PHEO. All 30 patients had prior surgery. Fourteen patients were refractory to prior radiation or chemotherapy before 131I-MIBG. Peripheral blood stem cells (PBSCs) were collected and cryopreserved. 131I-MIBG was synthesized on-site, by exchange-labeling 131I with 127I-MIBG in a solid-phase Cu2+-catalyzed exchange reaction. 131I-MIBG was infused over 2 h via a peripheral IV. Doses ranged from 557 mCi to 1185 mCi (7.4 mCi/kg to 18.75 mCi/kg). Median dose was 833 mCi (12.55 mCi/kg). Marrow hypoplasia commenced 3 weeks after 131I-MIBG therapy. After the first 131I-MIBG therapy, 19 patients required platelet transfusions; 19 received GCSF; 12 received epoeitin or RBCs. Four patients received a PBSC infusion. High-dose 131I-MIBG resulted in the following overall tumor responses in 30 patients: 4 sustained complete remissions (CRs); 15 sustained partial remissions (PRs); 1 sustained stable disease (SD); 5 progressive disease (PD); 5 initial PRs or SD but relapsed to PD. Twenty-three of the 30 patients remain alive; deaths were from PD (5), myelodysplasia (1), and unrelated cause (1). Overall predicted survival at 5 years is 75% (Kaplan Meier estimate). For patients with metastatic PHEO or PGL, who have good *I-MIBG uptake on diagnostic scanning, high-dose 131I-MIBG therapy was effective in producing a sustained CR, PR, or SD in 67% of patients, with tolerable toxicity.