ALBERT

Description: p18INK4c is a cyclin-dependent kinase (CDK) inhibitor that interferes with the Rb-kinase activity of CDK6/CDK4. Disruption of p18INK4c in mice impairs B-cell terminal differentiation and confers increased susceptibility to tumor development; however, alterations of p18INK4c in human tumors have rarely been described. We used a tissue-microarray approach to analyze p18INK4c expression in 316 Hodgkin lymphomas (HLs). Nearly half of the HL cases showed absence of p18INK4c protein expression by Reed-Sternberg (RS) cells, in contrast with the regular expression of p18INK4c in normal germinal center cells. To investigate the cause of p18INK4c repression in RS cells, the methylation status of the p18INK4c promoter was analyzed by methylation-specific polymerase chain reaction (PCR) and bisulfite sequencing. Hypermethylation of the p18INK4c promoter was detected in 2 of 4 HL-derived cell lines, but in none of 7 non-Hodgkin lymphoma (NHL)–derived cell lines. We also detected p18INK4c hypermethylation, associated with absence of protein expression, in 5 of 26 HL tumors. The correlation of p18INK4c immunostaining with the follow-up of the patients showed shorter overall survival in negative cases, independent of the International Prognostic Score. These findings suggest that p18INK4c may function as a tumor suppressor gene in HL, and its inactivation may contribute to the cell cycle deregulation and defective terminal differentiation characteristic of the RS cells.

Description: INTRODUCTION: Peripheral blood stem cell (PBSC) mobilization is impaired in patients receiving chemotherapy but, as far as we know there is no data about the impact of chemotherapy on different PB progenitor cell subpopulations. AIM: to ascertain whether or not immature or committed progenitor cell are affected by chemotherapy prior PBSC mobilization in NHL patients. MATERIAL AND METHODS: a total of 27 PB samples from NHL patients and 36 PB samples from healthy donors were studied. Immunophenotypic analysis of CD34+ cell subpopulations was performed using the following four colour combinations of monoclonal antibodies (FITC/PE/PC5/APC): CD90/CD133/CD38/CD34 and CD71/CD13/CD45/CD34. In order to study committed progenitor cells “in vitro”, standard colony-forming assays were used and, in order to investigate the behaviour of the uncommitted progenitors Delta Assays of plastic adherent progenitor cells (PΔ) were performed. RESULTS: The comparison between NHL patients and healthy donors is shown in Table 1. The relationship between data obtained by flow cytometry and cultures was statistically significant (p0.568) for all the progenitors analysed. Table 1: Results of Immunophenotypic and Functional Assays LNH patients Healthy donors p Data expressed as median (range). 1. Percentage among CD34+ cells. 2. Number of CFU/10 5 planted cells. 3. Number of CFU/10 6 planted cells % CD34 0.16(0.04–3.65) 0.57(0.11–1.81) 0.013 Immunophenotypic Data Erithroid 1 0.05(0.01–0.60) 0.14(0.02–0.42) 0.098 Myelo–monocytic 1 0.11(0.02–2.41) 0.37(0.07–1.18) 0.014 Immature 1 0.01(0.00–0.63) 0.05(0.01–0.19) 0.014 CFU-GM 2 70(4–440) 90(0–904) 0.327 Clonogenic and Delta Assays data BFU-E 2 62(6–172) 85(0–240) 0.046 CFU-Mix 2 18(0–124) 42(0–140) 0.018 CFU Δ3 356(0–3509) 953(90–8320) 0.033 CONCLUSIONS: We can conclude that in NHL, mobilized committed and above all immature progenitors are impaired when compared with healthy subjects, both analysed by immunological and functional assays. Only granulomonocytic progenitors analysed by a functional approach seemed to be preserved.

Description: DAC is a potent hypomethylating agent with clinical activity in patients with myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML). VPA is a histone deacetylase inhibitor used as an antiepileptic agent. In vitro, the combination of DAC with VPA results in synergistic antileukemia activity at doses of VPA above 1mM. Based on this data, we have developed a phase I/II study of this combination for pts with leukemia. The phase I of the study followed a classic 3+3 design. The dose of DAC was fixed: 15 mg/m2 iv daily for 10 days. This was based on a previous phase I study (Blood2004;103:1635) that indicated that this schedule had an optimal toxicity-response profile in this population. Three dose levels of VPA were selected: 20, 35 and 50 mg/kg. VPA was given orally for 10 days concomitantly with DAC. 22 pts have completed the phase I portion of the study (median age 56 years, range 4–78, 20 pts AML, 2 MDS). At dose level 1 (20 mg/kg of VPA) no grade III-IV toxicity was observed. At dose level 2 (VPA 35 mg/kg), 2 out 6 pts developed grade III neurotoxicity. Both pts were receiving high doses of other neurotropic agents. After IRB approval, 3 mores pts were treated at this dose level with no significant toxicity. Subsequently, 3 pts were treated at the highest planned dose level (50 mg/kg) with no toxicity observed. This cohort was then expanded to a total of 10 pts. One pt developed grade III neurotoxicity. No other severe drug-related toxicities were observed, but 5 patients at all dose levels developed grade II sedation/somnolence. Pancytopenia was induced in all pts. At dose level 1, one pt with refractory AML achieved complete remission (CR) after the second course of therapy. This is now maintained for 5 courses. At dose level 2, a patient with HIV disease and relapsed AML achieved CR after the third course of therapy, and 2 pts with relapsed AML achieved complete marrow responses (marrow blasts less then 5%, no recovery of peripheral counts). Of 3 pts evaluable for response at dose level 3, 1 pt with MDS has achieved CR after 1 course, and 1 with relapsed AML a complete marrow response. Median free VPA levels pretreatment were 0, and 25 mg/L on both days 5 and 10 and returned to 0 prior to next course. Histone acetylation measured by Western blot was observed in 3 pts (25%), all at doses above 20 mg/kg of VPA. Reactivation of p21 expression was induced in 4 out 11 pts analyzed. Global hypomethylation measured using a bisulfite PCR LINE assay was induced in 1 out 3 pts so far studied. Based on the toxicity observed, the phase II portion of the study was initiated. This is restricted to pts with AML/MDS. Seven pts have been accrued to this phase, and 8 out the 10 pts at dose level 3 of the phase I are also evaluable. The response data of this pts will be updated at the meeting. In summary, the combination of low dose DAC and VPA up to doses of 50 mg/kg can be safely administered to pts with leukemia although it may be complicated by neurotoxicity. Clinical and biological activity was observed at all dose levels.

Description: Introduction: Arsenic trioxide (AT) has impressive single agent activity in relapsed acute promyelocytic leukemia. It also has activity in myelodysplastic syndromes and multiple myeloma. In vitro data has suggested increased cytotoxicity when combined with agents that deplete intracellular glutathione, forming the rationale for combination studies. Ascorbic acid (AA) can deplete intracellular glutathione and may potentiate the cytotoxicity of AT. Upon this basis, we initiated a phase II study of arsenic trioxide plus ascorbic acid for relapsed/refracory lymphoid malignancies. Arsenic trioxide was administered at a dose of 0.25 mg/kg IV over one hour M-F for one week and then 2X/week for 5 weeks. Each arsenic infusion was followed by an infusion of 1000 mg ascorbic acid over 15 minutes. Each 6-week cycle was followed by a two-week rest period before repeating the cycle. Treatment was continued until best response plus two cycles or progressive disease. Patient characteristics: Median age 70.5 (37–88). Gender 10M, 6F. Histologies CLL/SLL (4), Follicular (3), Mantle Cell (3), DLBCL (2), Burkitt (2), Marginal Zone (1), Hairy Cell (1). Median # Prior therapies 4 (2–13). Refractory to prior treatment 13/16. Median ECOG PS 1 (0–2). B symptoms 3/16. Elevated LDH 8/16. Elevated B2M 13/16. Results: Median number of completed cycles 1 (0–4). Eight patients did not complete cycle #1, six due to progressive disease (PD) and 2 due to toxicity. Of the 2 patients coming off for toxicity, one patient with known coronary artery disease suffered a myocardial infarction on the 4th day of treatment and expired from congestive heart failure and the other experienced repeated grade 4 hyperglycemia. Six patients completed one cycle of therapy and were removed for PD. One patient completed 3 cycles of therapy before experiencing PD. One patient with mantle cell lymphoma received 4 cycles of therapy and achieved a CRu. The overall response rate was 6% (1/16). The responding patient’s treatment was stopped after 4 cycles for MD/patient preference and she experienced PD 5 months after completion of therapy. Grade 3 toxicities included thrombocytopenia (2 patients), anemia (3), neutropenia (1), stomatitis (1), anorexia (1), and elevated LFTs (1). Grade 4 toxicities included neutropenia (2) and hyperglycemia (1). Conclusions: AT plus AA in this dosing schedule had modest toxicity but limited antitumor activity. The data should be interpreted in the context of our heavily treated, essentially refractory patient population. Our trial had a two-stage design, and was closed due to lack of activity at the first stage analysis. Other doses and schedules may prove to be more efficacious.

Description: The nucleosome is the basic structure of chromatin. Changes in the biochemical composition of nucleosome-associated histone tails are associated with specific gene activation states, and are the target of several antineoplastic agents such as histone deacetylase inhibitors (HDI). Nucleosomes are constrained into loops that are flanked by domains known as matrix-attached regions (MARs). MARs contain DNA topoisomerase II (Topo II) consensus sequences. Topo II is responsible for regulating and maintaining DNA topology and is the target of several antineoplastic agents such as the anthracycline IDA, an effect mediated by the induction of double strand DNA breaks (DSB). We hypothesized that the combination of a Topo II inhibitor and a HDI will have synergistic antileukemia activity. VPA and SAHA are two HDIs currently studied in several clinical trials with known antileukemia activity and tolerable toxicity. To test our hypothesis and to develop future clinical studies, we have analyzed the effect of the combination of IDA, a potent Topo II inhibitor, with VPA or SAHA. We treated the leukemic cells lines MOLT4 and HL60 with increasing doses of IDA (0.5-20nM), SAHA (0.3-3μM) or VPA (0.25-3mM) daily for 3 days. First, using trypan blue viability assays, we identified the IC10 of IDA to be 0.5nM for MOLT4 and 1.5nM for HL60. Doses in excess of 2μM of SAHA or 3mM of VPA resulted in more than 90% decrease in cell viability in both cell lines. Subsequently, SAHA at doses of 0.075-1μM and VPA at 1-3mM were used for the combination experiments with IDA at its specific cell line IC10. At low doses of SAHA (0.075-0.45 μM) and VPA (0.25-1 mM) the combination was shown to have synergistic antileukemia activity by the Fractional Product Method of Webb. These results were confirmed using Annexin V assays. Of importance, growth inhibition was independent of the sequence used. To analyze the effects of this combination on DSB generation, we analyzed using immonocytochemistry and western blot, the induction of γH2AX, a histone variant that has been identified as an early event after the DSBs. SAHA alone induced a modest increase in γH2AX compared to baseline, whereas IDA alone had a significant effect that was not potentiated by the addition of SAHA. Histone H3 and H4 acetylation increased in a dose-dependent manner (2.4–15 fold) with both SAHA and VPA, starting at 0.3μM of SAHA and 0.25mM of VPA. The addition of IDA had no significant effect on histone acetylation. Because of previous data indicating that HDIs may down-regulate the expression of Topo II-alpha, the target of IDA, we have studied using real-time PCR its levels prior and during exposure to the different combinations. SAHA or VPA had no effect on Topo II-alpha mRNA levels whereas IDA induced 2.0–3.5 fold its expression in a dose-independent manner, an effect no altered by the addition of SAHA or VPA. Expression of p21CIP1, that is silenced in both cell lines, was restored by single agent VPA, SAHA or IDA. The combination of these drugs resulted in an additive effect in terms of p21CIP1 induction. Despite this phenomenon, no changes in cell cycle status were observed in these cells. In summary, the combination of IDA and SAHA or VPA has potent in vitro antileukemia effect, and should be studied in clinical trials.

Description: Introduction. The umbilical cord stem cell bank was created in Mexico City in june 2003 due to the need to have access to pluripotential stem cells to cover the hematological and immunological pediatric needs. We have so far 300 units of umbilical stem cells available to the medical community. The bank has been designed with a completely automatic process and the standards are based in NETCORD-FAHCT outlines. Objective. In the present study we made a balance of the evaluation of umbilical cord stem cell process including the maternal setting, the standarization of the methodology to obtain the stem cells, compared to other institutions around the world. Material and methods. Bayesian analysis allow us to evaluate our procedures at the different levels. Bayesian networks are directed acyclic graphs (DAGs) where the nodes are random variables and certain independence assumptions hold. Results. In table 1 we show the results of the first 300 units process with the automatic process. The arcs in a bayesian network specify the independence assumptions that must hold between the random variables and the global dependence of the total factors. Figure 1. Conclusion. Through the bayesian analysis, we found a direct influence of the collected volume, the time between the collection and the procedure, and the maternal unit, with respect to the number of recovered cells, specifically with CD34+ the viable ones as well as the totals. Figure 1. Bayesian Analysis between neonatal and process factors. Weight baby (PRN); sex (SRN); cord blood unit collected volume (ml); initial white cell (GBTI); total final white cell(GBTF); % total CD34+ ( PCD34T); % viable CD34+ (PCD34V); total CD43+ (CD34T); viable CD34+ (CD34VA); ginecology unit (UH); time hour (TH). Figure 1. Bayesian Analysis between neonatal and process factors. Weight baby (PRN); sex (SRN); cord blood unit collected volume (ml); initial white cell (GBTI); total final white cell(GBTF); % total CD34+ ( PCD34T); % viable CD34+ (PCD34V); total CD43+ (CD34T); viable CD34+ (CD34VA); ginecology unit (UH); time hour (TH). Results of the first 300 units process with these technology Initial nuclear cells/ml Collectionvolume Initial total nuclear cells % CD 34total Viable% CD 34 Recovery% Average 11.4 x 106/ml 102.8 ml 12.2 x108 0.32 0.31 80 Acceptance criterion 7–20 x 106 〉 75 ml 〉8 x 108 0.1– 0.3 0.1– 0.3 〉60%

Description: Aberrant DNA methylation of promoter-associated CpG islands is a frequent phenomenon in human leukemias, and in particular in adult ALL. Hck is a member of the Src family of tyrosine kinases, and functionally is located downstream of BCR-ABL signaling in chronic myelogenous leukemia (CML). Hck expression is limitedly to myeloid cells and B cell lymphocytes. Although some evidence indicates that Hck is required for malignant transformation and apoptosis, its role in leukemia is not fully understood. Here we analyze the role of aberrant DNA methylation of Hck in leukemia cell lines and patients. Using BLAT, we first identified the presence of a canonical CpG island in the near proximity of the transcription start site of HcK. To detect and measure DNA methylation, we designed a combined bisulfite restriction PCR assay. Using this assay, we found that Hck was methylated in 13 out of 23 hematopoietic and 8 out of 10 non-hematopoietic cell lines, but not in the bone marrow from 6 healthy individuals. We subsequently studied Hck expression by real-time PCR using GAPDH expression as an internal control. Hck expression was lower (dCT = −14.2± 3.6) in 7 Hck methylated cell lines than in 8 Hck unmethylated ones (dCT= −9.0± 3.5), p=0.017. All the cell lines studied were of myeloid or B cell origin. We then treated the Raji cell line with the hypomethylating agent 5-aza-2-deoxycytidine (DAC). DAC treatment resulted in partial hypomethylation of Hck and in an increment of Hck expression (dCT: −19.37 to −8.47). Subsequently, the effects of DAC treatment on Hck protein expression levels were analyzed using Western blot. These experiments showed a strong correlation between hypomethylation, gene re-expression and protein expression levels. These data therefore indicates that DNA methylation is an important aberrant regulator of Hck expression in leukemia cell lines. Based on the relevance of these findings, we then analyzed the frequency of Hck methylation in patients with leukemia. Using a cut-off of 10%, Hck was found to be methylated in 15 out of 44 (34%) patients with ALL, 9 out 23 pts (39%) with CML, and 3 out 10 pts (30%) with AML. Of importance, the density of Hck methylation was significantly higher in patients with ALL (mean 11.3%; range 0–76) compared to those with CML(5.2%; range 0–12) or AML ( 7.5%, range 0–14), p=0.02. Hck methylation was not associated with a B cell phenotype or the presence of the Philadelphia chromosome in patients with ALL. Nine ALL pts out of 15 with Hck methylation had died compared to 7 out 29 unmethylated (total ALL group n=34). Median survival had not been reached for the group of patients with no Hck methylation (n=29) compared to 116 weeks for those with Hck methylation (n=15) (p=0.08). All pts had been treated with hyperCVAD based chemotherapy. These data indicates that Hck methylation is a frequent phenomenon in human leukemia that maybe associated with a worse prognosis in ALL and suggests that Hck has a tumor suppressor like function in these disorders.

Description: Follicular lymphoma (FL) is the most common type of low-grade non-Hodgkin’s lymphoma. A subset of FL patients shows a favorable treatment response, and remains in complete remission with long-term follow-up, while another subset of patients has a clinical course characterized by frequent relapses and a shorter survival. Survival predictors for FL are mainly based on clinical data, and they seem to lack accuracy enough predicting survival among patients with advanced stage disease. The aim of this study is to build a survival predictor based on a set of biological markers using Tissue Micro Arrays (TMA). To this purpose, we have retrospectively analysed the expression of a group of 40 selected genes - related with apoptosis control, cell cycle, B-cell differentiation and signaling- in a series of 192 FLs using TMA. The association of these molecules with survival, and their usefulness to discriminate among FLIPI groups was evaluated. Results were quantified using different tools; singularly nuclear markers were scanned using the Bliss system and the quantitative expression was measured using the TMAscore v.1.0 image analysis software (Bacus Laboratories, Inc.). The mean overall survival (OS) was 74 months, and 38 months for progression-free survival (PFS). Statistically significant differences in OS were found with the Follicular Lymphoma International Prognostic Index (FLIPI) score (p 〈 0.01). No significant OS or PFS differences were observed between FL grades 1–3, between grades 3a and 3b, or using Ki67 expression. Univariate analysis revealed several TMA markers with capacity to predict OS and PFS. After multivariate analysis, a set of 4 apoptosis and cell-cycle markers was integrated into a FLIPI-independent clinical predictor, with the capacity to recognize two groups of FL patients with statistically significant differences in OS (83% versus 43% of OS at 120 months; p〈 0.001). Then, patients were classified into low-risk (FLIPI: 0–2) and high-risk groups (FLIPI: 3–5), and the protein-based predictor model was used in both groups. High-risk FLIPI patients were stratified by the protein-based predictor into two groups with OS probability of 79,3% versus 14,2% at 120 months, p 〈 0.001, and low-risk FLIPI patients were also separated into two groups with OS probability of 100% versus 60,4% at 120 months, p 〈 0.01. The model is now being validated in a blind set. These results suggest that an integrated use of the FLIPI and the protein-based model could reach a higher accuracy predicting survival in FL.

Description: Multiple myeloma (MM) remains as an incurable disease although new therapies can achieve a high rate of complete remissions (CR). Unfortunately, most patients ultimately relapse due to the persistence of minimal residual disease (MRD), and only a minority could be cured. Detection and quantification of these cells is an important tool for monitoring these patients and predicting a potential relapse. Here we analyze by RQ-PCR the MRD in MM patients achieving CR in order to classify them into different risk categories. MATERIAL AND METHODS: 38 MM patients uniformly treated according to the GEM-2000 (Spanish group for Myeloma) protocol, and that have achieved CR following PBSCT were included in the study. 22 were IgG, 9 IgA, 6 B-J and 1 non-secretory (κ/λ 21/16). 27 were male & 11 female with a median age of 58 (range 48–65). Bone marrow samples obtained at diagnosis and 3 months after transplant were analyzed. Complete (VDJH) and incomplete (DJH) Ig rearrangements were amplified with the Biomed-2 strategy (Leukemia2003;17:2257). PCR clonal products were sequenced on an ABI Prism 377 Sequence detector. VH, DH and JH segments were identified by comparing with germinal sequences on V-Base and BLAST databases. An ASO primer at the N-region was designed for each patient with the OLIGO 6.0 software. RQ-PCR was then performed on an ABI Prism 7700 using the ASO specific forward primer, a JH reverse intronic primer (JH1–6) and a TaqMan probe (JH1,2,4,5, JH3 or JH6) to amplify the patient specific rearrangement. Sample quality and quantity was controlled evaluating the standard curve of the albumin gene amplification. MRD was calculated according to ΔCT method. RESULTS: In 14 out of the cases included in the study, MRD investigation was not possible because the N-region was not longer enough to design the ASO primer (n=3), poor quality in the diagnostic sample to obtain the standard curve (n=8) or low plasma cell infiltration at diagnosis to obtain correct dilutions (n=3). The remaining 24 patients were classified into different risk groups according to the MRD level obtained 3 months after transplantation with a cut-off point of 0.01% tumor cells. Thus, progression free survival (PFS) was longer in those patients with MRD〈 10−4 (p=0.03, figure 1A). By contrast, upon comparing the impact on PFS of immofixation (IFX) in these 24 patients that were in CR (defined by conventional electrophoresis criteria), it was observed that patients with IFX (−) didn’t showed a different outcome from those IFX (+) (figure 1B). CONCLUSION: In summary, although RQ-PCR is a labor and time-consuming technique, it is an useful tool for monitoring MRD in MM. The level of 10−4 can contribute to classify patients into 2 groups (high and low MRD) with different risk of relapse that can be used to design specific therapies.