Circulating tumour cells in locally advanced head and neck cancer: preliminary report about their possible role in predicting response to non-surgical treatment and survival

BACKGROUND AND PURPOSE

The mechanism of dissemination of locally advanced head and neck cancer (LAHNC) is far to be resolved. Circulating tumour cells (CTC) have been identified as a prognostic factor in metastatic breast and prostate cancer. This prospective multi-centric analysis studied the possible role of CTC identification in LAHNC.

MATERIALS AND METHODS

CTC were searched in 73 patients with LAHNC (oropharynx, n=39; nasopharynx, n=10; larynx, n=10; paranasal sinuses, n=6, of whom 3 with sinonasal undifferentiated carcinoma, SNUC; hypopharynx, n=5; oral cavity, n=3). All of them (apart from SNUC) had squamous cell cancers. The relationship between CTC positivity and other clinical prognostic factors has been investigated. Response to treatment and survival has been related with changes in CTC number during the treatment.

RESULTS

CTC were frequently identified in oro- and hypopharyngeal cancer and in SNUC. They were more frequent in stage IV than in stages I-III disease (18% versus 6%, p=NS (not significant)). Partial or complete response (CR) was related with the absence or disappearance of CTC during treatment (p=0.017). A decrease in the CTC number or their absence throughout the treatment seems also related with non-progressive disease, after both complete or incomplete remission and with the proportion of patients alive and NED (no evidence of disease) (p=0.009).

CONCLUSIONS

These preliminary data suggest a possible role of CTC determination in head and neck cancer. Additional and longer follow up data need to be collected to confirm these findings.

Circulating tumor cells as predictors of prognosis in metastatic breast cancer: clinical application outside a clinical trial

AIMS AND BACKGROUND

Circulating tumor cells have a prognostic role in metastatic breast cancer. The aim of the study was to confirm the ability of circulating tumor cells, detected by the US Food and Drug Administration approved Cell Search assay, to predict the outcome of patients treated in a community general hospital.

PATIENTS AND METHODS

A prospective mono-institutional study was conducted at the Department of Medical Oncology at Spedali Civili, Brescia, Italy, from January 2009 to September 2010. A total of 93 consecutive patients with metastatic breast cancer were enrolled. Patients underwent a blood sample collection to detect circulating tumor cells at baseline and, subsequently, at the first follow-up examination (after 3-4 weeks from the beginning of a systemic therapy). A third sample was drawn at disease progression (at the beginning of a subsequent new course of therapy). The prognostic cutoff value of circulating tumor cells was fixed at 5 cells/7.5 ml of blood.

RESULTS

At baseline, median overall survival and progression-free survival in the subgroup ≥5 circulating tumor cells/7.5 ml of blood were significantly shorter (5 months and 3 months, respectively) than in the subgroup with <5 circulating tumor cells (8 months and 7 months, respectively) (P = 0.003 and P <0.001). At the first follow-up, the subgroup with more than 5 circulating tumor cells/7.5 ml of blood had a median overall survival of 4 months versus 8 months in the subgroup with <5 circulating tumor cells (P <0.001) and a median progression-free survival of 3 months versus 7 months respectively (P <0.001). At multivariate analysis, the level of circulating tumor cells at the first follow-up and at baseline remained significant as a predictor of progression-free and overall survival. The number of metastatic sites was significantly associated with overall and progression-free survival and correlated with the number of circulating tumor cells.

CONCLUSIONS

Our study confirms the role of circulating tumor cells as predictors of prognosis in metastatic breast cancer patients treated in general clinical practice.

P4-07-19: Bone Marrow Involvement Is Associated with High Numbers of Circulating Tumor Cells in Peripheral Blood of Metastatic Breast Cancer Patients

Introduction: Circulating Tumor Cells (CTCs) levels are dynamic indicators of prognosis and response to therapy in metastatic breast cancer (MBC) patients (pts). CTCs levels have been reported to be higher in pts with bone than visceral metastases, respectively. However, little is known about CTCs levels in pts with BM involvement. We analysed CTC patterns in patients with either visceral, bone or BM to test the hypothesis that BM involvement would facilitate tumor cells to enter the systemic circulation as CTCs. Patients and methods: Sites and extension of metastatic disease were identified with conventional imaging. Bone metastases were diagnosed with either bone scintigraphy or CT-PET and the BM involvement was documented histologically by BM biopsy and metabolically by CT-PET. A training set of 10 pts was evaluated by both BM biopsy and CT-PET to verify the diagnostic performance of CT-PET in identifying BM metastases (M+). We found a 100% concordance between BM biopsy and CT-PET and we therefore used CT-PET for further analyses. The CellSearch System (Veridex LLC, Raritan, NJ, USA) was used for the isolation and enumeration of CTCs in peripheral blood. The Student's t-test and the two-way ANOVA test were used to compare means of CTCs among patients with different metastatic patterns.

Results: The CTCs mean and median scores of 129 MBC pts were analysed. Final analysis focused on 101 pts with bone M+. Thirty-three pts had bone M+ alone and 68 pts had bone and visceral M+ (including lymphnodes, brain, liver and lung/pleura). Number of metastatic sites was 1, 2, 3, 4, 5 in 30%, 37%, 25%, 6% and 2% of pts, respectively. BM involvement was documented in 27 (27%) of pts in the whole series and in 12 (33%) of pts with bone M+ alone. Mean CTCs score in the whole series was 392 (0-9993) and the median number of CTCs was 20. In the whole series, BM involvement was associated with higher mean CTCs scores (1350 vs 42, p .014). In pts with bone M+ alone, mean CTCs score was 696 (0-7000) and pts with BM involvement had higher mean CTCs scores (1846 vs 39, p 0.37). Among the different metastatic patterns, the association of bone with BM involvement and liver M+ was correlated with the highest CTCs numbers. We could not perform comparisons in the 68 pts with both bone and visceral localizations because of the variety of metastatic patterns. However, the two-way ANOVA showed a significant influence of BM involvement on mean CTCs scores in pts with different metastatic patterns (p &gt;.001).

Conclusions: This work confirms that pts with bone metastases have higher numbers of CTCs than pts with visceral metastases. Extensive bone disease with BM involvement is characterized by an increase in CTCs numbers compared to bone disease without BM involvement. Bone marrow metastases are metabolically more active by CT-PET and can be accurately detected by metabolic imaging without need of BM biopsy. Further studies are ongoing.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-19.

Association between single nucleotide polymorphisms in the XRCC1 and RAD51 genes and clinical radiosensitivity in head and neck cancer

PURPOSE

Individual variability in radiosensitivity is large in cancer patients. Single nucleotide polymorphisms (SNPs) in genes involved in DNA repair and in protection against reactive oxygen species (ROS) could be responsible for such cases of radiosensitivity. We investigated the association between the occurrence of acute reactions in 101 patients with squamous cell carcinoma of the head and neck (SCCHN) after radiotherapy (RT) and five genetic polymorphisms: XRCC1 c.1196A>G, XRCC3 c.722C>T, RAD51 (c.-3429G>C, c.-3392G>T), and GSTP1 c.313A>G.

MATERIALS AND METHODS

Genetic polymorphisms were detected by high resolution melting analysis (HRMA). The development of acute reactions (oral mucositis, skin erythema and dysphagia) associated with genetic polymorphisms was modeled using Cox proportional hazards, accounting for biologically effective dose (BED).

RESULTS

Development of grade ≥2 mucositis was increased in all patients (chemo-radiotherapy and radiotherapy alone) with XRCC1-399Gln allele (HR=1.72). The likelihood of developing grade ≥2 dysphagia was higher in carriers of RAD51 c.-3429 CC/GC genotypes (HR=4.00). The presence of at least one SNP or the co-presence of both SNPs in XRCC1 p.Gln399Arg /RAD51 c.-3429 G>C status were associated to higher likelihood of occurrence of acute toxicities (HR=2.03).

CONCLUSIONS

Our findings showed an association between genetic polymorphisms, XRCC1 c.1196A>G and RAD51 c.-3429 G>C, and the development of radiation-induced toxicities in SCCHN patients.

Circulating tumor cells and cardiac metastasis from esophageal cancer: a case report

We report the case of a 67-year-old man affected by metastatic esophageal cancer. The patient developed a symptomatic heart metastasis presenting as mimicking ST-segment elevation myocardial infarction. Cardiac magnetic resonance imaging (MRI) documented the presence of a mass in the apex and septum of the left ventriculum. The dissemination of cancer was confirmed by the detection of circulating tumor cells (CTCs) in the peripheral blood, measured by the CellSearch System (Veridex, LLC, Raritan, N.J., USA). The blood sample drawn at cardiac disease progression revealed the presence of 2 CTCs per 7.5 ml of blood. This report highlights the potential role of CTCs as markers of metastatic spread.

Uncontrolled-rate freezing of peripheral blood progenitor cells allows successful engraftment by sparing primitive and committed hematopoietic progenitors

BACKGROUND AND OBJECTIVES

Uncontrolled-rate freezing (URF) techniques, which are fast and easy, could represent an attractive alternative to controlled-rate cryopreservation procedures which are time consuming and require high-level technical abilities. It was the aim of the present study to evaluate, on a routine basis, whether URF might spare primitive hematopoietic progenitors and maintain engrafting capacity.

DESIGN AND METHODS

One-hundred and nineteen peripheral blood progenitor cells (PBPC) collections from 104 patients with hematologic malignancies were cryopreserved in bags, with an URF procedure, in a cryoprotectant solution consisting of PBS, HSA and 10% DMSO and stored in liquid nitrogen. PBPC bags were tested before cryopreservation and at thawing for primitive (LTC-IC) and committed hematopoietic progenitors (CFU-Mix, BFU-E, CFU-GM) by means of long- and short-term culture assays, respectively. In addition, PBPC bags were evaluated for CD34+ cell numbers.

RESULTS

Although thawing was associated with a statistically significant reduction of the absolute number of nucleated cells, recovery of LTC-IC, CFU-Mix, BFU-E, CFU-GM and CD34+ cells was not affected by the freezing/thawing procedures. No adverse effects were reported at thawing and only mild transient reactions were recorded in 22 patients during reinfusion of cryopreserved PBPC. All the patients underwent myeloablative therapy followed by reinfusion of PBPC, and prompt and rapid hematopoietic recovery was obtained in all patients.

INTERPRETATION AND CONCLUSIONS

Our freezing procedure is fast and easy, and allows rapid hematopoietic recovery after myeloablative therapy by sparing primitive and committed hematopoietic progenitors. Our study strongly supports technical improvements aimed at cost reduction and feasibility of routine freezing procedures.

Proangiogenic properties of human myeloma cells: production of angiopoietin-1 and its potential relationship to myeloma-induced angiogenesis

Patients with multiple myeloma (MM) have increased bone marrow (BM) angiogenesis; however, the proangiogenic properties of myeloma cells and the mechanisms of MM-induced angiogenesis are not completely clarified. The angiopoietin system has been identified as critical in the regulation of vessel formation. In this study we have demonstrated that myeloma cells express several proangiogenic factors, and, in particular, we found that angiopoietin-1 (Ang-1), but not its antagonist Ang-2, was expressed by several human myeloma cell lines (HMCLs) at the mRNA and the protein levels. In a transwell coculture system, we observed that myeloma cells up-regulated the Ang-1 receptor Tie2 in human BM endothelial cells. Moreover, in an experimental model of angiogenesis, the conditioned medium of HMCLs significantly stimulated vessel formation compared with control or vascular endothelial growth factor (VEGF) treatment. The presence of anti-Tie2 blocking antibody completely blunted the proangiogenic effect of XG-6. Finally, our in vitro results were supported by the in vivo finding of Ang-1, but not Ang-2, mRNA and protein expression in purified MM cells obtained from approximately 47% of patients and by high BM angiogenesis in patients with MM positive for Ang-1, suggesting that the angiopoietin system could be involved, at least in part, in MM-induced angiogenesis.

Acute leukemia following a previous malignancy: do acute lymphoid leukemia and acute myeloid leukemia have common risk factors?

INTRODUCTION

Within the framework of the GIMEMA Study Group, the characteristics of acute lymphoid leukemia and acute myeloid leukemia occurring in patients who have suffered a previous malignancy were studied. Assessment was also made of the clinical course, laboratory features and overall outcome of these conditions.

MATERIALS AND METHODS

A four-year, multi-center retrospective study was conducted to evaluate the effect of treatment for previous hematological malignancy on the development of secondary leukemia. The study collected in the GIMEMA Archive of Adult Acute Leukemia 3934 new cases of acute leukemia (2964 AML, 901 ALL, 60 acute biphenotypic leukemia). Among these cases, data were evaluated from patients with a personal history of a previous malignancy, and included inquiring into demographic data, history of neoplastic diseases in the 1st degree relatives, type and treatment of the previous malignancy, latency until the development of a secondary acute leukemia diagnosis, laboratory features, treatment and outcome at the onset of secondary acute leukemia.

RESULTS

Approximately 200 (5.1%) patients presented a previous malignancy. Twenty-one were affected by ALL and 179 by AML. The proportion of patients with secondary AML was higher than that of patients with secondary ALL (179/2964 vs 21/901, O.R. 2.69-95% C.I. 1.66-4.39, P<0.001). The median latency, from the onset of the previous malignancy to the development of secondary ALL was 27 months and to the development of secondary AML was 52 months (P<0.05). Furthermore, of patients who previously received chemotherapy more developed a second AML (66/127 sAML vs 5/21 sALL; O.R. 3.46-95% C.I. 1.10-11.56, P<0.01).

CONCLUSION

In most cases, chemotherapy treatment for a previous malignancy can play a role in the development of secondary AML. In almost all cases of secondary ALL, the role of previous drugs does not appear to be relevant. On the basis of our analysis, performed systematically for the first time on a large adult series of acute leukemia, we conclude that in these patients a biological predisposition to cancer may be suspected.

Acute myeloid leukemia in patients previously diagnosed with breast cancer: experience of the GIMEMA group

OBJECTIVE

To evaluate in a multicenter retrospective study, the clinical and laboratory characteristics and the outcome of patients with acute myeloid leukemia (sAML) previously diagnosed with breast cancer (BC) among an adult acute leukemia population.

PATIENTS AND METHODS

Between June 1992 and July 1996, 3934 new cases of adults with acute leukemia were recorded in GIMEMA Archive of Adult Acute Leukemia (2964 AML, 901 ALL, 69 acute leukemia expressing both myeloid and lymphoid surface markers).

RESULTS

Two hundred patients (5.1%) presented with a history of previous malignancy (21 of them were affected by ALL and 179 by AML). Among sAML, 37 patients (29%) had a previous breast cancer. They consisted of 36 females and 1 male, median age 56 years, range 34-87. The median latency between the 2 malignancies was 54 months (range 5-379). Twenty-seven patients received chemo- and/or radiotherapy for breast cancer (7 only chemotherapy, 6 only radiotherapy, and 14 combined treatment). All patients were surgically treated but in 10 patients surgical debridement was the sole therapy for breast cancer. The drugs most frequently employed were alkylating agents (18 patients), topoisomerase II inhibitors (9 patients), antimetabolites (20 patients) (CMF, CEF and MMM combinations). At onset of sAML the median WBC count was 7.7 x 10(9)/l (0.8-153) and the median platelet count was 33.5 x 10(9)/l (3-305). Considering morphological features, FAB subtypes were 4 M0, 5 M1, 11 M2, 5 M3, 8 M4, 3 M5, and 1 M6. Cytogenetic study was performed on 28 patients and 12 of them presented abnormalities. It is noteworthy that chromosome 5 or 7 abnormalities (typically observed in those patients treated with alkylating agents) were present only in three cases. Thirty-four patients received chemotherapy for sAML, and twenty-five of them achieved a CR (74%), with a median duration of twenty-eight weeks (5-280+). The overall survival was 8 months (1-80+).

DISCUSSION

The high number of sAML we observed in patients with a previous breast cancer, may be due to the fact that this malignancy is the most frequent neoplasm in women and by the high probability of cure with a consequent long disease-free survival. Our results suggest that the risk of sAML after recovery from breast cancer is increasing due to the rise in the number of patients cured from breast cancer, and in the future could be a relevant problem for haematologists.

High-dose therapy in acute leukemia

The use of intensive induction chemotherapy, primarily with combinations of an anthracycline and cytarabine, allows complete remission rates of greater than 70% in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). However, with currently available standard-dose therapy, only 20% of young adults are cured. In order to substantially increase the cure rate, adequate post-remission therapeutic strategies are mandatory. Three different therapeutic options are currently available: (i) dose-intensified chemotherapy; (ii) allogeneic stem cell transplantation; (iii) autologous stem cell transplantation. These therapeutic options should be carefully evaluated according to prognostic information, including cytogenetic and molecular abnormalities as well as phenotypic characterization. Randomized trials of intensive postremission therapy have now confirmed improved leukemia-free survival with the use of allogeneic or autologous transplantation. Autologous transplantation appears to be the most promising treatment modality in AML. Improved preparative regimens and purging techniques may be critical factors in determining the effectiveness of autologous transplantation in AML patients. In adult ALL, the role and optimal methods of stem cell transplantation are still under investigation.

Biologic and phenotypic analysis of early hematopoietic progenitor cells in umbilical cord blood

Umbilical cord blood (UCB) is an attractive potential alternative to bone marrow (BM) as a source of hematopoietic progenitor cells since the number of progenitors in UCB is similar or even greater than that in normal BM. It was the aim of the present study to analyze the degree of immaturity of UCB progenitor cells. UCB mononuclear (MNC) and/or CD34+ cells were tested for surface antigen phenotype, expression of cytokines receptor, effect of stem cell factor (SCF) on colony growth, resistance to mafosfamide and replating potential. We have found that 34.9 +/- 3.4% and 77.9 +/- 2.6% of UCB CD34+ cells did not express CD38 and CD45RA antigens, respectively, suggesting that UCB contains a high proportion of immature progenitor cells. By means of three-color analysis, the receptor for SCF was detected on the majority of the CD34+ HLA-DR+ subpopulation; in fact, 81.8% +/- 4.3% of CD34+ HLA-DR+ cells were defined as SCF(low) and 8.1 +/- 1.5% as SCF(high). Colony growth of MNC and CD34+ cells was enhanced by the addition of SCF to methylcellulose mixture, resulting in a statistically significant increase in CFU-GM and CFU-GEMM but not in BFU-E numbers. UCB progenitor cells showed a higher resistance to mafosfamide treatment, in comparison to BM; the addition of SCF to the culture medium resulted in a statistically significant increase in mafosfamide concentration required to inhibit 95% of colony growth (P < or = 0.05). Moreover, as shown by single colony transfer assays, the presence of SCF in primary cultures promoted a significantly higher replating potential for both untreated (42 +/- 3.3% vs 21 +/- 4.6%, P < or = 0.018) and mafosfamide-treated samples (62 +/- 5.6% vs 44 +/- 6.1%, P < or = 0.018). In conclusion, UCB is a source of progenitor cells with immature characteristics in terms of surface antigen expression, distribution of SCF receptor, resistance to mafosfamide and replating potential. Therefore, UCB progenitor cells represent an ideal candidate population for experimental programs involving gene transfer and ex vivo stem cell expansion.

Clonogenic capacity and ex vivo expansion potential of umbilical cord blood progenitor cells are not impaired by cryopreservation

Umbilical cord blood (UCB) progenitor cells have been demonstrated to possess significant advantages over bone marrow (BM), in terms of proliferative capacity and immunologic reactivity. Therefore, UCB has been recently considered an attractive potential alternative to BM as a source of hematopoietic progenitor cells for clinical applications. Since several programs throughout the world are currently evaluating the feasibility of large-scale UCB banking for unrelated transplants, it was the aim of this study to evaluate whether cryopreservation procedures might heavily impair the clonogenic capacity, the feasibility of CD34+ selection and the ex vivo expansion potential of UCB progenitor cells. UCB samples were collected and cryopreserved as unseparated (n = 21) or mononuclear (MNC) cells (n = 15) within 12 h from delivery, and evaluated for viability, immunophenotype, cell and progenitor numbers after a minimum stay in liquid nitrogen of 6 months (range 6-14 months). Viability was always > 97% and no statistically significant difference was detected by flow cytometric analysis. Clonogenic recovery from unseparated cells was 80-87% for HPP-CFC, CFU-GEMM, BFU-E and CFU-GM, and from MNC cells ranged from 82 to 91% for LTC-IC, CFU-GEMM, BFU-E and CFU-GM. CD34+ selection (n = 8) was performed on fresh and cryopreserved MNC cells using the MiniMACS immunomagnetic separation device, showing no difference in yield (68 +/- 7% vs 57 +/- 4%, P < or = 0.4) or in purity (89 +/- 2% vs 81 +/- 6%, < or = 0.4), for fresh in comparison to cryopreserved MNC cells. After 14 days of liquid culture in the presence of different combinations of SCF, IL-3, IL-6 and G-CSF no statistically significant difference was detected in CFC fold-expansion for fresh or cryopreserved MNC cells and for CD34+ cells, either selected and cultured from fresh or cryopreserved MNC cells. In conclusion we can state that UCB is a potential source of primitive progenitor cells that can be cryopreserved unmanipulated or after physical separation without major losses in clonogenic capacity and immunophenotypic composition. Moreover, CD34+ selection from cryopreserved MNC cells is feasible and ex vivo expansion is not impaired. These results have important implications in the large scale UCB banking, in view of the potential applications of ex vivo expanded hematopoietic progenitor cells for the engraftment of adult patients.

In vitro growth of mobilized peripheral blood progenitor cells is significantly enhanced by stem cell factor

The existence of primitive hematopoietic progenitors in mobilized peripheral blood is suggested by clinical, phenotypic and in vitro cell culture evidences. In order to quantify primitive progenitors, 32 leukaphereses from 15 patients with lymphoid malignancies were investigated for the growth of multilineage colony-forming units (CFU-Mix), erythroid burst-forming units (BFU-E) and granulocyte-macrophage colony-forming units (CFU-GM) in the absence or presence of recombinant stem cell factor (SCF), a cytokine which selectively controls stem cell self-renewal, proliferation and differentiation. Primitive progenitors were also quantitated by means of a long-term assay which allows the growth of cells capable of initiating and sustaining hematopoiesis in long-term culture (LTC-IC). Addition of SCF (50 ng/ml) to methyl-cellulose cultures stimulated with maximal concentrations of G-CSF, GM-CSF, interleukin 3 and erythropoietin significantly increased the growth (mean +/- SE) of CFU-Mix (7.7 +/- 1.7 versus 2.4 +/- 0.6, p < or = 0.0001), BFU-E (47 +/- 10 versus 32 +/- 6, p < or = 0.002) and CFU-GM (173 +/- 31 versus 112 +/- 20, p < or = 0.0001). Mean (+/- SE) percentages of SCF-dependent CFU-Mix, BFU-E and CFU-GM were 60 +/- 5%, 19 +/- 5%, and 33 +/- 4%, respectively. Mean (+/- SE) LTC-IC growth per 2 x 10(6) nucleated cells was 221 +/- 53 (range, 2 to 704). Linear regression analysis demonstrated a statistically significant correlation (r = .87; p < or = 0.0001) between LTC-IC and SCF-dependent progenitors. In conclusion, our data suggest that: A) the optimal quantification of mobilized progenitors requires supplementation of methylcellulose cultures with SCF, and B) in vitro detection of SCF-dependent progenitors might represent a reliable and technically simple method to assess the primitive progenitor cell content of blood cell autografts. Such in vitro evaluation of immature hematopoietic progenitors might be clinically relevant for predicting the reconstituting potential of autografts.

Selection of myeloid progenitors lacking BCR/ABL mRNA in chronic myelogenous leukemia patients after in vitro treatment with the tyrosine kinase inhibitor genistein

Chronic myelogenous leukemia (CML) is a clonal disorder of the hematopoietic stem cell characterized by a chimeric BCR/ABL gene giving rise to a 210-kD fusion protein with dysregulated tyrosine kinase activity. We investigated the effect of genistein, a protein tyrosine kinase inhibitor, on the in vitro growth of CML and normal marrow-derived multi-potent (colony-forming unit-mix [CFU-Mix]), erythroid (burst-forming unit-erythroid [BFU-E]), and granulocyte-macrophage (colony-forming unit-granulocyte-macrophage [CFU-GM]) hematopoietic progenitors. Continuous exposure of CML and normal marrow to genistein induced a statistically significant and dose-dependent suppression of colony formation. Genistein doses causing 50% inhibition of CML and normal progenitors were not significantly different for CFU-Mix (27 mumol/L v 23 mumol/L), BFU-E (31 mumol/L v 29 mumol/L), and CFU-GM (40 mumol/L v 32 mumol/L v 32 mumol/L). Preincubation of CML and normal marrow with genistein (200 mumol/ L for 1 to 18 hours) induced a time-dependent suppression of progenitor cell growth, while sparing a substantial proportion of long-term culture-initiating cells (LTC-IC) from CML (range, 91% +/- 9% to 32% +/- 3%) and normal marrow (range, 85% +/- 8% to 38% +/- 9%). Analysis of individual CML colonies for the presence of the hybrid BCR/ABL mRNA by reverse transcription-polymerase chain reaction (RT-PCR) showed that genistein treatment significantly reduced the mean +/- SD percentage of marrow BCR/ABL+ progenitors both by continuous exposure (76% +/- 18% v 24% +/- 12%, P < or = .004) or preincubation (75% +/- 16% v 21% +/- 10%, P < or = .002) experiments. Preincubation with genistein reduced the percentage of leukemic LTC-IC from 87% +/- 12% to 37% +/- 12% (P < or = .003). Analysis of individual colonies by cytogenetics and RT-PCR confirmed that genistein-induced increase in the percentage of nonleukemic progenitors was not due to suppression of BCR/ABL transcription. Analysis of nuclear DNA fragmentation by DNA gel electrophoresis and terminal deoxynucleotidyl transferase assay showed that preincubation of CML mononuclear and CD34+ cells with genistein induced significant evidence of apoptosis. These observations show that genistein is capable of (1) exerting a strong antiproliferative effect on CFU-Mix, BFU-E, and CFU-GM while sparing the more primitive LTC-IC and (2) selecting benign hematopoietic progenitors from CML marrow, probably through an apoptotic mechanism.

Effect of the protein tyrosine kinase inhibitor genistein on normal and leukaemic haemopoietic progenitor cells

Receptor and nonreceptor protein tyrosine kinases (PTKs) play a key role in the control of normal and neoplastic cell growth. The availability of PTK inhibitors prompted us to evaluate the effects of genistein, a natural inhibitor of PTKs, on in vitro colony formation by normal multilineage colony-forming units (CFU-Mix), erythroid bursts (BFU-E), granulocyte-macrophage colony-forming units (CFU-GM), long-term culture-initiating cells (LTC-IC) and acute myelogenous leukaemia colony-forming units (CFU-AML). Continuous exposure of normal marrow and blood mononuclear non-adherent cells, blood CD34+CD45RA- cells, and leukaemic blasts to increasing doses of genistein (1-100 microM) resulted in a statistically significant (P < or = 0.05) dose-dependent suppression of CFU-Mix, BFU-E, CFU-GM and CFU-AML growth. Regression analysis showed that growth inhibition was linearly related to genistein concentration. Genistein dose causing 50% inhibition (ID50) of CFU-AML was significantly lower compared to CFU-GM ID50 for marrow (19 v 32 microM, P < or = 0.017), unseparated blood (19 v 44 microM, P < or = 0.028) or CD34+CD45RA- blood (19 v 36, P < or = 0.04). Preincubation of leukaemic blasts with genistein (200 microM) for 1-2h confirmed that CFU-AML were significantly more sensitive than normal marrow and blood CFU-GM to genistein. Preincubation conditions which maximally suppressed leukaemic and normal colony growth spared a substantial percentage of marrow (29 +/- 4%) and blood (40 +/- 3%) LTC-IC. In conclusion, our data demonstrate that: (a) genistein strongly inhibits the growth of normal and leukaemic haemopoietic progenitors; (b) growth inhibition is dose- and time-dependent; (c) leukaemic progenitors are more sensitive than normal progenitors to genistein-induced growth inhibition; (d) genistein exerts a direct toxic effect on haemopoietic cells while sparing a substantial proportion of LTC-IC. The potent CFU-AML growth inhibition associated with the relative resistance of normal LTC-IC strongly supports the use of genistein for marrow purging.

BCL2 oncogene protein expression in human hematopoietic precursors during fetal life

BCL2 proto-oncogene encodes a 25-kD protein that is characteristically localized in the inner mitochondrial membrane of the cell. It has been reported that BCL2 protein has the unique functional role of blocking programmed cells death without affecting proliferation. We have analyzed the expression of the BCL2 protein in fetal hematopoietic tissues from the 10th week of gestational age onward. Fetal thymus, liver, and bone marrow and cord blood were investigated. The experiments were performed by the alkaline-antialkaline phosphatase (APAAP) technique by staining air-dried acetone-fixed cytospins and by dual-color immunofluorescent assay by staining mononuclear cell suspensions with monoclonal antibodies detecting BCL2 protein and antigens expressed by different hematopoietic subsets. Flow cytometric analyses were performed on FACSort's Comsort 32 (Becton Dickinson, San Jose, CA). The results have shown that the BCL2 protein is expressed in human fetal ontogenesis at the earliest stages examined. The major conceptual aspects of the results are 1) BCL2 is largely expressed in the hematopoietic cells during ontogenesis. BCL2+ cells include both immature and more differentiated subsets. Moreover, the 25-kD protein is expression in cell subsets well known to be high proliferating. This behavior suggests that BCL2 could have more complex functions than those previously described. 2) The expression in the major part of CD34+ cells suggests that BCL2 could play a role in stem cell survival. 3) BCL2 is expressed in not only medullary but also cortical thymocytes, where it could cooperate in positive selection processes. 4) The involvement of BCL2 in the immunosurveillance is indicated not only by its role in B and T cell lineages but also by its expression in particular subsets like that of the cytoplasmic CD3+ fetal liver NK cells. 5) The discrepancy observed between the results of transgenic mice analysis and in vitro inhibition experiments by antisense oligonucleotides performed for understanding BCL2 functions must stress the importance of the direct immunologic analysis of BCL2 in human hematopoietic cells.

Density separation and cryopreservation of umbilical cord blood cells: evaluation of recovery in short-and long-term cultures

The clonogenic capacity of human umbilical cord blood (UCB) has been evaluated in several studies, which have shown high numbers of primitive hematopoietic progenitor cells. Recently, UCB progenitor cells were demonstrated to possess significant advantages over bone marrow (BM) in terms of proliferative capacity and immunologic reactivity. Therefore, UCB has been considered an attractive source of hematopoietic stem cells for both research and clinical applications. Previous reports have documented a significant loss of progenitor cells by any manipulation other than cryopreservation. We have evaluated the feasibility of fractionating and cryopreserving UCB samples with minimal loss of progenitor cells. We compared separation over three different densities of Percoll (1.069, 1.077 and 1.084 g/ml), sedimentation over poligeline (Emagel), and sedimentation over poligeline followed by separation over Ficoll/Hypaque (F/H). Separated samples (n = 25) were analyzed for recovery of CD34+ cells and progenitor cells (CFU-GEMM, BFU-E, CFU-GM). Separation by sedimentation over poligeline followed by F/H allowed the highest depletion of RBCs (hematocrit of the final cellular suspension 0.4 +/- 0.1%), while maintaining a high recovery of CD34+ cells (85.3%) and total recovery of CFU-GEMM, BFU-E and CFU-GM. After cryopreservation, recovery of clonogenic progenitors was 82% for CFU-GEMM, 94% for BFU-E, 82% for CFU-GM and 90% for colony-forming units after 5 weeks of longterm culture. Moreover, the presence of Stem cell factor significantly increased CFU-GEMM (14 +/- 4 vs. 49 +/- 5, p < or = 0.0005) and CFU-GM (112 +/- 18 vs. 178 +/- 19, p < or = 0.025), but not B FU-E (42 +/- 7 vs. 53 +/- 7, p < or = 0.375) growth. In conclusion, RBC depletion of UCB can be accomplished with minimal loss of committed and primitive hematopoietic progenitors. This procedure may have important implications in the large-scale banking of UCB and in ex vivo expansion/gene therapy protocols.

Density separation of umbilical cord blood and recovery of hemopoietic progenitor cells: implications for cord blood banking

Umbilical cord blood (CB) has been evaluated as a potential source of hematopoietic stem cells suitable for clinical use in the transplantation setting. Previous reports have documented a significant loss of progenitor cells by any manipulation other than cryopreservation. We have evaluated the feasibility of fractionating and cryopreserving CB samples with minimal loss of progenitor cells. We have compared various separation procedures based on different density gradients in the attempt to obtain the highest depletion of red blood cells (RBC) while maintaining the highest recovery of progenitor cells. We compared three different densities of Percoll (1.069 g/ml, 1.077 g/ml, 1.084 g/ml), sedimentation over poligeline (Emagel ) and sedimentation over poligeline followed by separation over Ficoll/Hypaque (F/H). Separated samples (n = 25) were analyzed for recovery of CD34+ cells and progenitor cells (CFU-GEMM, BFU-E, CFU-GM). Separation by sedimentation over poligeline followed by F/H allowed the highest depletion of RBC (hematocrit of the final cellular suspension 0.4 +/- 0.1%) while maintaining high recovery of CD34+ cells (85.3 +/- 5.6%) and total recovery for CFU-GEMM, BFU-E and CFU-GM. After cryopreservation, recovery of clonogenic progenitors was 82% for CFU-GEMM, 94% for BFU-E, 82% for CFU-GM and 90% for colony-forming units (CFUs) after five weeks of long-term culture (LTC). We further evaluated the effect of stem cell factor (SCF) on the in vitro growth of hemopoietic progenitors and on replating efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)