Expression of CD133-1 and CD133-2 in ovarian cancer

Cancer stem cells have been isolated from several solid tumors including prostate, colon, liver, breast, and ovarian cancer. Stem cells isolated from nervous system and prostate express CD133 antigen, which is widely used to isolate hematopoietic stem and progenitor cells. The aims of this study were to investigate the expression of the CD133-1 and CD133-2 epitopes in primary ovarian tumors and to biologically characterize CD133(+) ovarian cancer cells, also according to clinicopathologic parameters. Tissue specimens were obtained at primary surgery from 41 ovarian carcinomas; eight normal ovaries and five benign ovarian tumors were also collected. Flow cytometry with monoclonal antibodies against CD133-1 and CD133-2 epitopes was employed. FACS (fluorescence activated cell sorting) analysis enabled the selection of CD133(+) cells, whose epithelial origin was confirmed by immunofluorescence analysis with monoclonal anti-cytokeratin 7. CD133(+) cells gave rise to a 4.7 +/- 0.9-fold larger number of colonies than that documented in CD133(-) population (P < 0.001). Moreover, CD133(+) cells showed an enhanced proliferative potential compared to CD133(-) cells. The percentages of CD133-1- and CD133-2-expressing cells were significantly lower in normal ovaries/benign tumors with respect to those in ovarian carcinoma. Both the percentages of CD133-1- and CD133-2-expressing cells were significantly lower in omental metastases than in primary ovarian cancer (P = 0.009 and 0.007 for CD133-1- and CD133-2-expressing cells, respectively). There seems not to be any difference in the distribution of the percentage of CD133-1- and CD133-2-expressing cells according to clinicopathologic parameters and response to primary chemotherapy. CD133-1 and CD133-2 may be useful in order to select and enrich the population of CD133(+) ovarian tumor cells, which are characterized by a higher clonogenic efficiency and proliferative potential.

Quercetin inhibits the growth of a multidrug-resistant estrogen-receptor-negative MCF-7 human breast-cancer cell line expressing type II estrogen-binding sites

It has been demonstrated that the flavonoid quercetin (3,3',4',5,7-pentahydroxyflavone; Q) inhibits the growth of several cancer cell lines. There is evidence suggesting that the antiproliferative activity of this substance is mediated by the so-called type II estrogen-binding site (type II EBS). We looked for the presence of type II EBS and the effect of Q on the proliferation of an Adriamycin-resistant estrogen-receptor-negative human breast-cancer cell line (MCF-7 ADRr). By whole-cell assay using estradiol labelled with 6,7-tritium [( 3H]-E2) as a tracer, we demonstrated that MCF-7 ADRr cells contain type II EBSs. Competition analysis revealed that diethylstilbestrol (DES) and Q competed with similar potency for [3H]-Es binding to type II EBSs. The antiestrogen tamoxifen (TAM) competed for type II EBSs, albeit to a lesser extent than either DES or Q. Growth experiments demonstrated that Q and DES exerted a dose-dependent inhibition of cell proliferation in the range of concentrations between 10 nM and 10 microM, whereas TAM was less effective. Q could also inhibit colony formation in a clonogenic assay. Our results indicate that multidrug-resistant estrogen-receptor-negative MCF-7 cells express type II EBSs and are sensitive to the inhibitory effect of Q. This substance could be the parent compound of a novel class of anticancer agents.

Red blood cell alloimmunization in sickle cell disease and in thalassaemia: current status, future perspectives and potential role of molecular typing

Red blood cell (RBC) transfusions are a milestone in the treatment for sickle cell anaemia (SSA) and for thalassaemia. RBC alloimmunization remains a major challenge of chronic transfusion therapy, and it can lead to adverse life-threatening events. The alloimmunization risk could depend on multiple factors such as the number of transfusions and, most of all, the genetic background. Different ethnic groups are predisposed to immunization because of a significant degree of RBC antigenic mismatch between donor and recipient. There is no universal agreement and standards for the most appropriate selection of RBC units in chronically transfused subjects. Current practice only deals with compatibility of ABO, Rh and K antigens. Molecular RBC antigenic matching extended to other blood group systems is an innovative strategy to ensure a better quality and effectiveness of transfusion therapy.

Erythropoietin addition to granulocyte colony-stimulating factor abrogates life-threatening neutropenia and increases peripheral-blood progenitor-cell mobilization after epirubicin, paclitaxel, and cisplatin combination chemotherapy: results of a randomized comparison

PURPOSE AND METHODS

The ability of granulocyte colony-stimulating factor (G-CSF) plus erythropoietin (EPO) treatment was compared in a randomized fashion with that of G-CSF treatment alone in promoting hematologic recovery and peripheral-blood progenitor-cell (PBPC) mobilization in previously untreated patients with advanced ovarian cancer who underwent their first course of epirubicin, paclitaxel, and cisplatin (ETP) chemotherapy during a phase II study of intensive outpatient ETP chemotherapy followed by high-dose carboplatin, etoposide, and melphalan (CEM) late intensification with PBPC support.

RESULTS

Comparative analysis of hematologic recovery of 50 randomized patients, after ETP chemotherapy, showed that life-threatening neutropenia occurred in 88% of the patients treated with G-CSF alone, whereas it occurred in only 4% of patients treated with G-CSF + EPO. Significantly different WBC and polymorphonuclear leukocyte (PMN) counts were observed in the two distinct arms on the day of WBC nadir (P <.0001 and P <.0001, respectively). Moreover, the addition of EPO to G-CSF increased PBPC mobilization and collection as compared with that in G-CSF-treated patients (P =.0009 and P =.0026, respectively), who required a significantly higher number of leukaphereses than G-CSF + EPO-treated patients (P =.0076) to obtain the planned minimum dose of PBPCs. Qualitative analysis by cloning assay of PBPCs collected in both arms revealed that G-CSF- and G-CSF + EPO-mobilized PBPCs have comparable in vitro functional properties.

CONCLUSION

This randomized comparison revealed that EPO significantly increases most of the hematologic effect produced by G-CSF administration after chemotherapy. This biologic property of EPO translated in vivo into a global improvement of patients' hematologic status.

A prospective, active haemovigilance study with combined cohort analysis of 19,175 transfusions of platelet components prepared with amotosalen-UVA photochemical treatment

BACKGROUND AND OBJECTIVES

A photochemical treatment process (PCT) utilizing amotosalen and UVA light (INTERCEPT(™) Blood System) has been developed for inactivation of viruses, bacteria, parasites and leucocytes that can contaminate blood components intended for transfusion. The objective of this study was to further characterize the safety profile of INTERCEPT-treated platelet components (PCT-PLT) administered across a broad patient population.

MATERIALS AND METHODS

This open-label, observational haemovigilance programme of PCT-PLT transfusions was conducted in 21 centres in 11 countries. All transfusions were monitored for adverse events within 24 h post-transfusion and for serious adverse events (SAEs) up to 7 days post-transfusion. All adverse events were assessed for severity (Grade 0-4), and causal relationship to PCT-PLT transfusion.

RESULTS

Over the course of 7 years in the study centres, 4067 patients received 19,175 PCT-PLT transfusions. Adverse events were infrequent, and most were of Grade 1 severity. On a per-transfusion basis, 123 (0.6%) were classified an acute transfusion reaction (ATR) defined as an adverse event related to the transfusion. Among these ATRs, the most common were chills (77, 0.4%) and urticaria (41, 0.2%). Fourteen SAEs were reported, of which 2 were attributed to platelet transfusion (<0.1%). No case of transfusion-related acute lung injury, transfusion-associated graft-versus-host disease, transfusion-transmitted infection or death was attributed to the transfusion of PCT-PLT.

CONCLUSION

This longitudinal haemovigilance safety programme to monitor PCT-PLT transfusions demonstrated a low rate of ATRs, and a safety profile consistent with that previously reported for conventional platelet components.

A human umbilical cord stem cell rescue therapy in a murine model of toxic liver injury

BACKGROUND

Several studies have demonstrated that bone marrow contains a subpopulation of stem cells capable of participating in the hepatic regenerative process, even if some reports indicate quite a low level of liver repopulation by human stem cells in the normal and transiently injured liver.

AIMS

In order to overcome the low engraftment levels seen in previous models, we tried the direct intraperitoneal administration of human cord blood stem cells, using a model of hepatic damage induced by allyl alcohol in NOD/SCID mice.

METHODS

We designed a protocol based on stem cell infusion following liver damage in the absence of irradiation. Flow cytometry, histology, immunohistochemistry and RT-PCR for human hepatic markers were performed to monitor human cell engraftment.

RESULTS

Human stem cells were able to transdifferentiate into hepatocytes, to improve liver regeneration after damage and to reduce the mortality rate both in both protocols, even if with qualitative and quantitative differences in the transdifferentiation process.

CONCLUSIONS

We demonstrated for the first time that the intraperitoneal administration of stem cells can guarantee a rapid liver engraftment. Moreover, the new protocol based on stem cell infusion following liver damage in the absence of irradiation may represent a step forward for the clinical application of stem cell transplantation.

CD105 (endoglin) expression on hematopoietic stem/progenitor cells

Endoglin (CD105) is a component of the transforming growth factor-beta (TGF-beta) receptor (TGF-betaR) complex. Together with betaglycan, CD105 is considered as a TGF-betaR accessory molecule (also called TGF-betaRIII), but its functions in the receptor-ligand interactions are still poorly understood. A small subset of human CD34+ hematopoietic stem/progenitor cells that has phenotypic and functional features suggestive of very primitive hematopoietic cells expresses the CD105 antigen. CD34+/CD105+ cells recirculate in the peripheral blood of mobilized subjects and can be purified by immunomagnetic isolation strategies. The hematopoietic potential of these CD34+/CD105+ cells appears to be sustained by a combination of hematopoietic and non-hematopoietic cytokines, which comprises Flt3 ligand, erythropoietin, interleukin-15 and vascular endothelial growth factor. Endogenous TGF-beta1 is a crucial factor for the maintenance of CD34+/CD105+ immaturity acting through positive modulation of both CD105 and CD34 molecules in the absence of relevant effects on the cell cycle profile. CD105 is absent on very primitive CD34-/lineage-/CD45+ (CD34-Lin-) human hematopoietic cells isolated from cord blood. However, in vitro exposure of CD34-Lin- cells to exogenous TGF-beta1 causes the appearance of a discrete population of CD34+/CD105+ cells. Collectively, available data on CD105 expression and function in primitive hematopoiesis indicate that this molecule could cooperate with the dissociation of TGF-beta1 cell cycle effects from its other effects on cell survival and differentiation.

Immune reconstitution after transplantation of autologous peripheral CD34+ cells: analysis of predictive factors and comparison with unselected progenitor transplants

The recovery of lymphocyte count, CD4+ and CD8+ T-cell subsets, natural killer (NK) cells and CD19+ B-cells was evaluated in a cohort of 15 patients receiving autologous CD34+ peripheral blood progenitor cells (PBPCs; group A) for haematological malignancies and in 20 patients transplanted with autologous unselected PBPCs (group B). Lymphocyte count recovered in both patient cohorts, being significantly lower in group A than in group B 1 (P = 0.008) and 2 months (P = 0.0035) after progenitor cell infusion. The repopulation of CD3+ T-cells occurred more rapidly in group B than in group A (P = 0.034 on week 4); CD19+ B-lymphocytes did not return to reference ranges in either group of patients. The count of CD4+ T-lymphocytes remained < 200/microl during the study period in patients transplanted with CD34+ PBPCs, significantly lower than group B levels (P = 0.034 and P = 0.021 on weeks 4 and 8 respectively). CD8+ T-cells increased rapidly in both groups; thus, the CD4 to CD8 ratio was severely reduced. CD4+ and CD8+ T-cells displayed an activated phenotype in both groups of patients, co-expressing the HLA-DR antigen throughout the study period. NK cells followed a similar repopulation kinetics in both study groups, although their expansion was greater in group B than in group A (P = 0.014 on week 4). In the CD34+ group, post-transplant administration of granulocyte colony-stimulating factor predicted a faster lymphocyte recovery in multivariate analysis (P = 0.025); interestingly, the amount of passively transferred lymphocytes correlated inversely with time to achieve a lymphocyte count > 0.5 x 10(9)/l (r = -0.63, P = 0.01). Further investigations are necessary to characterize T-cell competence after transplantation of CD34+ PBPCs.

CD34+/CD105+ cells are enriched in primitive circulating progenitors residing in the G0 phase of the cell cycle and contain all bone marrow and cord blood CD34+/CD38low/- precursors

A subset of circulating CD34+ cells was found to express CD105 antigen. Sorting experiments showed that most granulocyte-macrophage colony-forming units (GM-CFU) and burst-forming units - erythroid (BFU-E) were retained in the CD34+/CD105- fraction, whereas rare GM-CFU/BFU-E were generated from CD34+/CD105+ cells. Megakaryocytic aggregates were entirely retained in the CD34+/CD105+ fraction. Neutralizing doses of an anti-TGF-beta1 antibody demonstrated CD34+/CD105+ cells capable of colony-forming activity without any significant effect on CD34+/CD105- cells. Cloning of secondary colonies revealed that CD34+/CD105+ cells had a significantly higher secondary cloning efficiency than CD34+/CD105- cells. CD34+/CD105+ cells had a significantly higher long-term culture-initiating cell (LTC-IC) frequency than CD34+/CD105- cells. Kinetic analysis showed that 75% of CD34+/CD105+ cells consisted of DNA 2n G0Ki-67- cells whereas 82% of CD34+/CD105- were DNA 2n G1Ki-67+ cells, and this latter subset showed a RNA content consistently higher than CD34+/CD105+ cells. CD34+/CD105+ progenitors were CD25+, whereas CD34+/CD105- contained a small CD25+ subset. Three-colour analysis of bone marrow and cord blood CD34+ cells demonstrated that all the CD34+/CD38low/- primitive precursors were contained in CD34+/CD105+ cells. Extensive characterization of these CD105+ precursors indicated that they have biological properties associated with primitive haematopoietic precursors.

The combination of quercetin and cytosine arabinoside synergistically inhibits leukemic cell growth

It has been demonstrated that quercetin (3,3',4',5,7-pentahydroxyflavone) inhibits the growth of several cancer cell lines and that the antiproliferative activity of this substance is probably mediated through a binding interaction with type II estrogen binding sites (type II EBS). The effect of quercetin and cytosine arabinoside (Ara-C) alone or in combination, was tested on HL-60 cell growth. Quercetin significantly synergized the inhibitory activity of Ara-C on HL-60 cell growth while rutin, the 3-rhamnosylglucoside of quercetin, neither competed with [3H]estradiol for type II EBS nor was effective alone or in combination with Ara-C. Based on these results, we studied by a clonogenic assay the effect of quercetin and Ara-C alone and in combination on colony formation by human leukemic cells (CFU-L). In all cases both drugs exhibited a dose-related inhibition of CFU-L in a range of concentrations between 10 nM and 10 microM and 0.01 nM and 10 microM for quercetin and Ara-C, respectively. The combination of the two drugs resulted in a synergistic inhibitory activity on CFU-L. Considering that plasma concentrations of quercetin effective in vitro were obtained in vivo without any apparent side effects, we conclude that this report represents further experimental evidence that quercetin could be used in the treatment of acute leukemias.

Antiproliferative activity of quercetin on normal bone marrow and leukaemic progenitors

We used an in vitro clonogenic assay in semi-solid medium to test the sensitivity of normal bone marrow and acute myeloid and lymphoid leukaemia progenitors to the flavonol quercetin. We have studied 14 acute myeloid (AML) and four acute lymphoid (ALL) leukaemias. All ALL and the vast majority of AML (12/14) had a high sensitivity to quercetin with more than 50% growth inhibition at 2 x 10(-6) M quercetin. One M3-AML was partially quercetin-sensitive displaying 60% surviving AML-colony forming units (CFU-AML) at a quercetin concentration of 10(-5) M. One M1-AML was resistant to the growth inhibitory effect of quercetin at a concentration of 2 x 10(-5) M. The clonogenic efficiency of both AML and ALL positively correlated with leukaemic colony-forming unit (CFU-L) sensitivity to quercetin suggesting that this parameter can be useful in predicting quercetin responsiveness of leukaemic cells. We have also studied the effect of various quercetin concentrations on colony formation by normal bone marrow cells. At a quercetin concentration of 10(-5) M, we observed (in five different experiments) a mean recovery of 53% and 65% of erythroid blast-forming units (BFU-E) and granulocyte-macrophage colony-forming units (CFU-GM), respectively. Thus, normal bone marrow appeared partially resistant to quercetin, being inhibited less than 50% by quercetin concentration higher than 2 x 10(-5). When normal bone marrow were deprived in CD34+ haematopoietic progenitors the resultant population became highly sensitive to quercetin, with a mean recovery of BFU-E and CFU-GM of 5% and 12% of controls respectively in the presence of 2 x 10(-5) M quercetin. Furthermore, CD34 progenitors, positively selected, appeared fully resistant to quercetin concentrations as high as 2 x 10(-5) M. Thus, CD34+ progenitors are a quercetin-resistant component in normal bone marrow. In conclusion, our results further provide a biological basis for the therapeutic use of quercetin, considering that this compound could inhibit leukaemic cell growth without suppressing normal haematopoiesis.

Efficacy of granulocyte transfusions for neutropenia-related infections: retrospective analysis of predictive factors

BACKGROUND

The transfusion of G-CSf-primed granulocytes (GTX) might represent an important treatment option for neutropenia-related infections unresponsive to conventional antimicrobial therapies and to recombinant hematopoietic growth factors. However, few studies to date have identified the factors that can predict clinical outcome and the patient populations who are likely to benefit most from GTX. The primary endpoint of the present retrospective study was to evaluate the efficacy of GTX in 22 patients with hematological malignancies who developed neutropenia-related bacterial and fungal infections that were unresponsive to appropriate antimicrobial therapies.

METHODS

Peripheral blood granulocytes were collected by continuous-flow leukapheresis from HLA-identical siblings after priming with G-CSF. The response to GTX was classified as 'favorable' if clinical symptoms and signs of infection resolved or 'unfavorable' if clinical symptoms and signs of infection were unchanged or worsened. Control of infection at Day 30 after the enrollment in the GTX program was considered as the outcome variable in multiple regression analysis.

RESULTS

Two patients died of infection before receiving the granulocyte concentrates. Bacterial infections (monomicrobial or mixed bacteremias) were documented in 11 patients, whereas fungal infections (fungemia or focal fungal infections) were diagnosed in seven patients. In two patients, no infecting agent could be isolated (clinical infection). Control of infection at Day 30 after the first GTX was achieved in 10 of 20 assemble patients. Overall, 54% of patients with bacterial infections had a favorable response, compared with 57% of patients with fungal infections. No differences in terms of survival were found when comparing patients with bacterial and those with fungal infections at a median follow-up 90 days from the first GTX. In univariate analysis, disease status before GTX, e.g., complete or partial remission, and spontaneous recovery of the neutrophil count were significantly associated with control of infection. when multivariate regression models were formed, the recovery 0.5 x 10 (9)/L PMN was the only parameter that significantly and independently correlated with a favorable response to GTX.

DISCUSSION

GTX can be used to successfully treat bacterial as well as fungal infections in severely neutropenic patients when administered early after the onset of febrile neutropenia in patients with remission of the underlying disease and who are likely to recover marrow function.

Transfected human dendritic cells to induce antitumor immunity

Dendritic cells are professional antigen-presenting cells able to prime naive T lymphocytes and regulate steadily the delicate balance between tolerance and activation during the immune response. In past years several reports have shown that genetically engineered dendritic cells (DCs) can be a powerful tool for inducing an antigen-specific immune response. The use of such modified antigen-presenting cells is a real working hypothesis in preclinical studies and in clinical vaccination approaches for cancer treatment. The definition of optimal transfection conditions for preserving DC survival and functionality is necessary to design a correct immunotherapeutic protocol. Different lipid-based transfection compounds were studied for their effects on DC survival, phenotype and functional properties. All the transfection procedures were able to select DCs with a higher expression of activation and costimulatory molecules (ie MHCII-DR, CD83, CD86, CD25) than the untreated DCs. However, only two compounds (LipofectAMINE PLUS and FuGENE 6), preserved or even increased the immunopotency of DCs as antigen-presenting cells. These protocols were applied to modify DCs in order to express an epithelial tumor-associated antigen, MUC1, and such cells were able to induce in vitro a specific immune response in healthy donors.

Accurate prediction of autologous stem cell apheresis yields using a double variable-dependent method assures systematic efficiency control of continuous flow collection procedures

BACKGROUND AND OBJECTIVES

Stem cell collection is a standard procedure for the procurement of autologous grafts to rescue myelosuppression induced by high-dose treatments. Accurate prediction of collection yields may contribute to optimize planning and quality control of collection.

MATERIALS AND METHODS

Data of 313 autologous haematopoietic stem cell (AHSC) evaluable collections performed in 208 patients with haematologic and non-haematologic neoplasms from seven centres were prospectively analysed to test the accuracy of yield predictions generated by a formula that required the input of peripheral blood (PB) CD34+ cell precount and desired PB volume to be processed. Data were matched in a standard linear regression, in a zero-point regression analysis and tested for prediction accuracy. Further 165 AHSC collections were analysed on a single-centre basis, using yield predictions as reference standards.

RESULTS

Analysis showed high levels of correlation between measured collection yields (my) and predictions (py) (R = 0.85; P = 0.000000) as well as high degree of prediction accuracy (my vs. py at paired t-test: P = 0.114781; median my/py ratio = 1.23). Analysis of additional 165 AHSC collections on a single-centre basis showed that the analysed centres had 70% or more measured yields comprising the 0.6-1.8 interval of the my/py ratio. The observance of the 'efficiency' my/py interval assured collection quality control in these centres confirming the reliability of the method.

CONCLUSIONS

This prediction method generates accurate and immediate yield predictions allowing collection planning and rapid efficiency control. As a consequence of our study, four centres out of seven use the described method to plan both leukapheresis number and single-procedure blood processing volume while the remaining three centres plan leukapheresis number on the basis of our predictions, maintaining a fixed single-procedure 200 ml/kg blood volume processing, according to their centre AHSC collection policy.

Further investigations on the expression of HLA-DR, CD33 and CD13 surface antigens in purified bone marrow and peripheral blood CD34+ haematopoietic progenitor cells

We evaluated the HLA-DR, CD33 and CD13 antigen expression on CD34+ haematopoietic progenitor cells (HPC) isolated from the bone marrow (BM) and peripheral blood (PB) of normal donors. The majority of both BM and PB CD34+ HPC expressed CD13 and HLA-DR. The coexpression of CD34 and CD33 was found in a minor CD34+ subset. After 7 d of culture in the presence of interleukin-3 and granulocyte-macrophage colony-stimulating factor, CD33 expression was detected in about 50% of HPC. At this point CD34 antigen expression was lost and CD13 and HLA-DR expression was partially lost. After 14 d of culture, the majority of HPC were CD33+. HPC maintained the capacity to generate colony forming unit granulocyte-macrophage but they lost the capacity to generate burst forming unit-erythroid. A correlation was found between the percentage of CD34+/HLA-DR+ cells and the total number of colony forming cells in unfractionated samples from BM and PB of patients with malignancies. These studies demonstrate that, in normal conditions, only a minor subset of CD34+ cells coexpress CD33 antigen either in BM or in PB and CD33 antigen is a lineage marker which is coexpressed with HLA-DR and CD13 on a progenitor committed to the granulocytic-macrophagic lineage.

Autologous blood stem cell harvesting and transplantation in patients with advanced ovarian cancer

We investigated the feasibility of a programme of autologous blood stem cell (ABSC) harvesting and transplantation in 13 patients with advanced ovarian cancer, previously untreated by chemotherapy or radiotherapy and entering a phase II study of high-dose cisplatin, etoposide and carboplatin with haematopoietic stem cell rescue. Prior to high-dose treatment all patients underwent two courses of cisplatin and cyclophosphamide. An 8-fold increase of the peripheral colony forming unit granulocytic-macrophage (CFU-GM) was observed during recovery from myelosuppression after the first chemotherapy course. The second course determined a 2.5-fold increase of peripheral CFU-GM. In 70% of enrolled patients (nine patients) we were able to perform ABSC harvesting by leukaphereses; in the apheresed patients we harvested an average of 20.8 x 10(4)/kg CFU-GM (range 10.9-37.0). Haematopoietic trilineage engraftment, established as the number of days necessary to reach white blood cells (WBC) greater than 1.0 x 10(9)/l, polymorphonuclear leucocytes (PMN) greater than 0.5 x 10(9)/l and platelets (PLT) greater than 50 x 10(9)/l, occurred very promptly and was sustained in the same series after high-dose cisplatin, carboplatin and etoposide, followed by autologous blood stem cell transplantation (ABSCT). In our experience we found a significant correlation (r = 0.77; P less than 0.05) between CFU-GM infused dose and the engraftment speed of PMN. We conclude that the combination of cisplatin and cyclophosphamide is effective in mobilizing haematopoietic progenitors in the peripheral blood of patients with advanced ovarian cancer, previously untreated by chemoradiotherapy. Moreover, ABSCT is capable of rapidly restoring the haematopoietic function after high-dose treatment and for this reason it represents a particularly advisable therapeutic option for the treatment of solid tumours because these patients are commonly older than 50 and can be excluded from bone marrow transplantation.

Expression of cyclin-dependent kinase inhibitor p15(INK4B) during normal and leukemic myeloid differentiation

OBJECTIVE

Expression of the cyclin-dependent kinase inhibitor p15(INK4B) frequently is altered in myeloid malignancies. We previously demonstrated that p15(INK4B) is expressed in normal myeloid cells. The aim of this study was to investigate whether p15(INK4B) expression is restricted to the granulomonocytic lineage and to evaluate its modulation during normal and leukemic myeloid differentiation.

MATERIALS AND METHODS

Normal CD34(+) cells were cultured in serum-free media to obtain granulomonocytic, erythroid, or megakaryocytic unilineage differentiation. NB4 promyelocytic cell line and fresh leukemic blasts from seven patients with acute promyelocytic leukemia were cultured with all-trans retinoic acid. At different times of culture, cell samples were collected to evaluate p15(INK4B) by semiquantitative reverse transcriptase polymerase chain reaction.

RESULTS

p15(INK4B) mRNA was found during granulomonocytic and megakaryocytic, but not erythroid, differentiation. In the granulomonocytic lineage, p15(INK4B) was detectable when the majority of cells were at the promyelocytic stage and increased progressively in more mature elements. In the megakaryocytic lineage, p15(INK4B) was expressed in the early phase of differentiation, before megakaryoblasts had appeared, and was mantained throughout the time of culture. NB4 cell line and five of seven leukemic samples displayed undetectable or very low level of p15(INK4B) that rapidly increased during retinoic acid-induced differentiation. Two leukemic samples (both collected from two patients developing all-trans retinoic acid syndrome) showed high basal levels of p15(INK4B), which was not modified by retinoic acid treatment.

CONCLUSIONS

p15(INK4B) upregulation occurs specifically during normal granulomonocytic and megakaryocytic commitment. In acute promyelocytic leukemic blasts, p15(INK4B), which is detectable at a very low level, is promptly increased by retinoic acid. In contrast, two acute promyelocytic leukemia samples obtained from patients who developed all-trans retinoic acid syndrome showed high basal levels of p15(INK4B) that did not increase further during all-trans retinoic acid-induced differentiation.

Immune reconstitution after autologous peripheral blood progenitor cell transplantation: effect of interleukin-15 on T-cell survival and effector functions

OBJECTIVE

The aim of this study was to evaluate the occurrence of T-cell spontaneous apoptosis (A(spont)) and its modulation in vitro by the interleukin-2 receptor (IL-2R) gamma-chain (gammac)-signaling cytokine IL-15 in patients transplanted with autologous peripheral blood progenitor cells (PBPC) for hematologic malignancies.

MATERIALS AND METHODS

Patients were examined on days 30-60, 60-90, and 90-120 after PBPC infusion. Dissipation of mitochondrial transmembrane potential, a hallmark of T-cell apoptosis, has been detected using the fluorescent probe 3,3'-dihexyloxacarbocyanine iodide, after short-term T-cell culture in the absence or presence of exogenous cytokines. Expression of Bcl-2 family members has been studied by flow cytometry and reverse transcriptase polymerase chain reaction. T-cell proliferative responses to recall antigens have been estimated in autologous mixed leukocyte cultures.

RESULTS

A(spont) was seen in 45% +/- 6% of CD4(+) and 55% +/- 6% of CD8(+) T cells cultured in the absence of cytokines. Of interest, IL-15 and, to a lesser extent, its structural cousin IL-2 counteracted T-cell A(spont) by inhibiting the processing of caspase-3 and up-regulating Bcl-2 mRNA and protein levels. Cell division tracking confirmed that IL-15 did not rescue T cells from A(spont) by promoting proliferation but rather acted as a genuine survival factor. Addition of a gammac-blocking antibody to cytokine-conditioned cultures abrogated both apoptosis inhibition and Bcl-2 induction by IL-15, suggesting involvement of the IL-2Rgammac signal transduction pathway. Whereas cytokine-unprimed posttransplant T cells mounted inadequate responses to recall antigens, T cells conditioned with IL-15 expanded vigorously, indicating restoration of antigen-specific proliferation.

CONCLUSIONS

T cells recovering after autologous PBPC transplantation are highly susceptible to spontaneous apoptosis in vitro. This phenomenon can be counteracted by the gammac-signaling cytokine IL-15. These findings suggest that IL-15 might be a promising immunomodulating agent to improve postgrafting T-cell function.

Granulocyte colony-stimulating factor perturbs lymphocyte mitochondrial function and inhibits cell cycle progression

Sera from healthy subjects receiving recombinant human granulocyte colony-stimulating factor (rHuG-CSF) to mobilize CD34(+) peripheral blood progenitors (PBPC) have been recently shown to induce unresponsiveness of allogeneic lymphocytes to mitogenic challenge. In the present investigation, the effects of rHuG-CSF on the early stages of lymphocyte activation-induced apoptosis and on lymphocyte cell cycle entry were evaluated. Sera were obtained from HLA-identical donors receiving rHuG-CSF to mobilize CD34(+) PBPC for allogeneic transplantation. Normal peripheral blood mononuclear cells (PBMC) were challenged with phytohemagglutinin (PHA) in the presence of serum collected before (preG) or after rHuG-CSF administration (postG). Mitochondrial function, that is, incorporation of 3,3'-dihexyloxacarbocyanine iodide [DiOC(6)(3)] and generation of reactive oxygen species (ROS) as well as expression of c-Myc and Bcl-2 family members (Bcl-2, Bcl-X(L), Bax) were evaluated by multiparameter flow cytometry. The activation-induced fragmentation of genomic DNA was detected by highly sensitive LM-PCR assay.CD4(+)DiOC(6)(3)(low) and CD8(+)DiOC(6)(3)(low) T lymphocytes increased and reached 32% (range 27%-38%) and 20% (range 15%-23%) of circulating T cells, respectively, on day 4 of rHuG-CSF administration. Hypergeneration of ROS could be demonstrated in 65% (range 58%-82%) of CD4(+) T lymphocytes and in 0.4% (range 0.2%-0. 8%) of circulating CD8(+) T cells. rHuG-CSF determined no alteration of mitochondrial function if added to allogeneic PBMC in vitro, thus suggesting indirect effects mediated by soluble factors; on the contrary, when PBMC were challenged with PHA in the presence of postG serum, both perturbation of mitochondrial transmembrane potential (Deltapsi(m)) and hypergeneration of ROS were induced, and lymphocytes were predominantly arrested in a G(0) -like phase of the cell cycle and displayed genomic DNA fragmentation. Interestingly, the preincubation of PBMC with a blocking antibody directed against CD95 abrogated the perturbation of lymphocyte Deltapsi(m), suggesting that the CD95 signaling pathway might play a role in the induction of apoptosis after PHA stimulation in the presence of postG serum. Moreover, Bax protein was overexpressed in postG (median fluorescence intensity = 180, range 168-186) compared with preG cultures (median fluorescence intensity = 75, range 68-80; p < 0.01), while no differences in Bcl-2, Bcl-X(L), and c-Myc staining intensity were observed. Our findings demonstrate a humoral-mediated rHuG-CSF-induced dissipation of lymphocyte mitochondrial Deltapsi(m); these effects might be mediated by Bax overexpression, with imbalance between apoptosis-promoting and apoptosis-inhibiting Bcl-2 family members and with subsequent induction of mitochondrial permeability transition. Whether immune dysfunction will favorably impact on incidence and severity of acute graft vs host disease after allogeneic PBPC transplantation remains to be determined.

Transforming growth factor-beta1 transcriptionally activates CD34 and prevents induced differentiation of TF-1 cells in the absence of any cell-cycle effects

A number of cytokines modulate self-renewal and differentiation of hematopoietic elements. Among these is transforming growth factor beta1 (TGF-beta1), which regulates cell cycle and differentiation of hematopoietic cells, but has pleiotropic activities depending on the state of responsiveness of the target cells. It has been previously shown by us and other authors that TGF-beta1 maintains human CD34(+) hematopoietic progenitors in an undifferentiated state, independently of any cell cycle effects, and that depletion of TGF-beta1 triggers differentiation accompanied by a decrease in CD34 antigen expression. In the present work, we show that exogenous TGF-beta1 upregulates the human CD34 antigen in the CD34(+) cell lines TF-1 and KG-1a, but not in the more differentiated CD34(-) cell lines HL-60 and K-562. We further studied this effect in the pluripotent erythroleukemia cell line TF-1. Here, TGF-beta1 did not effect cell growth, but induced transcriptional activation of full-length CD34 and prevented differentiation induced by differentiating agents. This effect was associated with nuclear translocation of Smad-2, activation of TAK-1, and with a dramatic decrease in p38 phosphorylation. In other systems TGF-beta1 has been shown to activate a TGF-beta-activated kinase 1 (TAK1), which in turn, activates p38. The specific inhibitor of p38 phosphorylation, SB202190, also increased CD34 RNA expression, indicating the existence of a link between p-38 inhibition by TGF-beta1 and CD34 overexpression. Our data demonstrate that TGF-beta1 transcriptionally activates CD34 and prevents differentiation of TF-1 cells by acting independently through the Smad, TAK1 and p38 pathways, and thus provide important clues for the understanding of hematopoietic development and a potential tool to modify response of hematopoietic cells to mitogens or differentiating agents.

Effect of age on DNA binding of the ku protein in irradiated human peripheral blood mononuclear cells (PBMC)

DNA binding of the ku protein was investigated in peripheral blood mononuclear cells (PBMC) from 24 subjects of different ages (20-89 years old) displaying age-related changes in DNA repair, mitotic responsiveness, and cytokine production. Ku is an heterodimeric protein composed of two subunits of 70 and 80 kDa, which is involved in the earliest steps of DNA damage recognition. DNA binding of ku 70/80 was found unchanged in normal PBMC from aging subjects but progressively declined in x-ray-irradiated PBMC from young to adult, and elderly subjects. This finding was concomitant with the age-related fall of DNA repair in the whole population.

Functional, phenotypic and molecular characterization of cytokine low-responding circulating CD34+ haemopoietic progenitors

Circulating CD34+ cell populations characterized by a low rate (up to five) or high rate (more than five) of cell divisions were isolated from 8 d cultures in the presence of stem cell factor (SCF), interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), erythropoietin (EPO), Flt3 ligand and Peg-rHu megakaryocyte growth and development factor (Peg-rHuMGDF) using the fluorescent dye 5,6-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) and flow cytometric cell sorting. Phenotypic characterization of cells which had experienced up to five divisions (CFDA-SEbright) showed a similar surface antigen expression to starting, freshly isolated CD34+ cells. Conversely, cells which experienced more than five divisions (CFDA-SEdim) showed a differentiating behaviour, down-regulating CD34 antigen and acquiring differentiation markers. CFDA-SEbright cells were significantly enriched in CD105 (endoglin) positive precursors as compared to both freshly isolated CD34+ and CFDA-SEdim cells. Functional analysis indicated that CFDA-SEbright had a 3-fold and 10-fold greater cumulative cloning efficiency as compared to freshly isolated CD34+ cells and CFDA-SEdim cells, respectively. CFDA-SEbright cells retained the vast majority of LTC-IC and showed a LTC-IC frequency 2.8-fold higher than that found in freshly isolated CD34+ cells. RT-PCR and Western blot analyses showed significantly higher bcl-2 RNA and protein levels in CFDA-SEbright cells as compared to freshly isolated CD34+ and CFDA-SEdim cells. This study indicates that cytokine low-responding circulating CD34+ cells (CFDA-SEbright cells) represent a functionally, phenotypically and molecularly distinct multipotent progenitor population with biological properties associated with primitive precursors.

Haemopoietic reconstitution after autologous blood stem cell transplantation in patients with malignancies: a multicentre retrospective study

A retrospective study was undertaken to evaluate the efficacy of autologous blood stem cell transplantation (ABSCT) in terms of haemopoietic reconstitution after ablative chemotherapy or chemo-radiotherapy. 55 patients with malignancies, observed in four Italian institutions from January 1987 to June 1991, were eligible for evaluation. This series included 19 non-Hodgkin's lymphoma, 11 multiple myeloma, nine ovarian cancer, seven Hodgkin's disease, seven non-lymphocytic leukaemia, one acute lymphoblastic leukaemia, one neuroblastoma. 522 PBSC collections were performed on 55 patients. Following ABSCT, the rate of engraftment was positively related to the dose of CFU-GM infused and negatively to the presence of bone marrow involvement at conditioning. 48 patients out of 55 transplanted (87%) had rapid, complete and sustained engraftment. Three patients (5%) died of transplant-related complications. Considering that 60% of the patients in this series were in partial remission or in progressive disease at the time of ABSCT, we conclude that ABSCT is a safe approach for the use of ablative conditioning therapy in patients with a wide scope of malignancies, provided that a large number of CFU-GM have been collected after mobilizing treatment.

Evaluation of a novel automated protocol for the collection of peripheral blood stem cells mobilized with chemotherapy or chemotherapy plus G-CSF using the Fresenius AS104 cell separator

Forty-seven peripheral blood stem cell (PBSC) collections were carried out on patients mobilized with chemotherapy and 63 on patients mobilized with chemotherapy plus G-CSF (Filgrastim), using the Fresenius AS104 cell separator and a novel automated PBSC collection protocol. As expected, cell yields were significantly higher in the series mobilized using chemotherapy plus G-CSF. The low platelet and red blood cell contamination permitted freezing of the apheresis product without further manipulation, other than plasma removal in both series. In patients mobilized with chemotherapy we obtained a MNC and a hemopoietic progenitor (CFU-GM, BFU-e, and CD34+ cells) collection efficiency comparable or superior to those reported by Bender (1992) with the Baxter CS3000 Plus after mobilization with cyclophosphamide. A significant decrease in MNC, BFU-e, and CD34+ cell collection efficiency was found in patients mobilized with chemotherapy plus G-CSF compared to those obtained in patients mobilized with chemotherapy alone. Ten patients achieved a prompt and stable engraftment after high dose chemotherapy and the infusion of cryopreserved PBSC collected using this protocol. Studies are in progress in order to improve MNC and hemopoietic progenitor collection efficiency in patients mobilized with G-CSF to obtain a graft in no more than one or two procedures.