Agnieszka Janus

General population low-count CLL-like MBL persists over time without clinical progression, although carrying the same cytogenetic abnormalities of CLL

Monoclonal B-cell lymphocytosis (MBL) is classified as chronic lymphocytic leukemia (CLL)-like, atypical CLL, and CD5(-) MBL. The number of B cells per microliter divides CLL-like MBL into MBL associated with lymphocytosis (usually detected in a clinical setting) and low-count MBL detected in the general population (usually identified during population screening). After a median follow-up of 34 months we reevaluated 76 low-count MBLs with 5-color flow cytometry: 90% of CLL-like MBL but only 44.4% atypical CLL and 66.7% CD5(-) MBL persisted over time. Population-screening CLL-like MBL had no relevant cell count change, and none developed an overt leukemia. In 50% of the cases FISH showed CLL-related chromosomal abnormalities, including monoallelic or biallelic 13q deletions (43.8%), trisomy 12 (1 case), and 17p deletions (2 cases). The analysis of the T-cell receptor β (TRBV) chains repertoire showed the presence of monoclonal T-cell clones, especially among CD4(high)CD8(low), CD8(high)CD4(low) T cells. TRBV2 and TRBV8 were the most frequently expressed genes. This study indicates that (1) the risk of progression into CLL for low-count population-screening CLL-like MBL is exceedingly rare and definitely lower than that of clinical MBL and (2) chromosomal abnormalities occur early in the natural history and are possibly associated with the appearance of the typical phenotype.

Antigen receptor stereotypy across B-cell lymphoproliferations: the case of IGHV4-59/IGKV3-20 receptors with rheumatoid factor activity

Antigen receptor stereotypy across B-cell lymphoproliferations: the case of IGHV4-59/IGKV3-20 receptors with rheumatoid factor activity

No influence of 3435C>T ABCB1 (MDR1) gene polymorphism on risk of adult acute myeloid leukemia and P-glycoprotein expression in blast cells

Inherited differences in xenobiotic transport and metabolism may play an important role in the development of adult acute myeloid leukemia (AML) and response to the chemotherapy. An ATP-binding cassette (ABC) family transporter P-glycoprotein (P-gp or ABCB1), encoded by ABCB1 (MDR1) gene, is involved in the protection against xenobiotics and multi-drug resistance. The aim of this study was to investigate the potential involvement of the ABCB1 gene exon 26 3435C>T single nucleotide polymorphism (SNP) in the genetic susceptibility to AML and regulation of P-gp expression and activity in AML cells. A total of 180 adult AML patients and 180 sex-matched controls were genotyped using PCR-RFLP method. Moreover, in 40 AML patients ABCB1 gene expression was studied by real-time RT-PCR and P-gp expression and activity were assessed by flow cytometry assays. The prevalence of 3435C>T ABCB1 polymorphism was similar in patient and control cohorts (P = 0.16). Furthermore, the carriers of different ABCB1 genotypes did not differ significantly according to ABCB1 gene expression (P = 0.99), P-gp expression (P = 0.42) and P-gp activity (P = 0.83) in leukemic cells. The authors conclude that isolated 3435C>T ABCB1 SNP is not a major factor of the genetic susceptibility to adult AML, and that genotyping of this polymorphism does not allow predicting P-gp expression or activity in AML cells.

Rapamycin, the mTOR kinase inhibitor, sensitizes acute myeloid leukemia cells, HL-60 cells, to the cytotoxic effect of arabinozide cytarabine

The mammalian target of rapamycin (mTOR) kinase is a key regulator of cell growth and proliferation. Overexpression of the mTOR signaling pathway has been described in several tumor cells, including the majority of acute myeloid leukemia (AML) cases. The anti-tumor efficacy of mTOR inhibitors was shown in several preclinical and clinical studies. In AML, however, the potential antineoplastic effect of mTOR inhibitors has received little attention thus far. In this in-vitro study of the human AML cell line, HL-60, we aimed to assess the antileukemic activity of rapamycin (RAPA), an mTOR inhibitor, alone and in combination with cytarabine (Ara-C). The study showed that RAPA in concentrations of 1–10 nmol/l arrested the cell cycle progression of Hl-60 cells in the G1 phase, without evident cytotoxic effect. This effect was associated with significant inhibition of cyclin E expression. At concentrations higher than 10 nmol/l, RAPA exerted a significant proapoptotic effect, with the collapse of mitochondrial potential and caspase-3 activation. The most prominent proapoptotic effect was observed for a combination of 1 nmol/l of RAPA and 50 nmol/l of Ara-C, especially when Ara-C was added at a 24-h interval after RAPA. In conclusion, these data indicate that RAPA might be effective in the treatment of acute leukemia patients, especially in combination with Ara-C, the drug routinely used in AML treatment. On the basis of these results, attempts to combine classical induction chemotherapy with an inhibitor of the mTOR kinase in AML treatment could be warranted.

Cladribine combined with cyclophosphamide and mitoxantrone is an active salvage therapy in advanced non-Hodgkin's lymphoma.

The aim of this study was to determine the feasibility, efficacy and toxicity of the combined therapy consisting of cladribine (2-CdA), mitoxantrone and cyclophosphamide (CMC regimen) in patients with refractory or relapsed non-Hodgkins lymphoma (NHL). Thirty six patients, 14 with mantle cell lymphoma (MCL), 10 with diffuse large B-cell lymphoma (DLBCL), 5 with follicular lymphoma (FL), 3 with small lymphocytic lymphoma (SLL), and 4 with T-cell lymphoma were enrolled to the study. The CMC protocol consisted of 2-CdA at a dose of 0.12 mg/kg in a 2-hour infusion on days 1 through 3, mitoxantrone 10 mg/m2 i.v. on day 1 and cyclophosphamide 650 mg/m2 i.v. on day 1. The CMC courses were repeated at intervals of 4 weeks. Thirty three patients were available for evaluation of response. Overall response rate (OR) was 58% (95% CI, 41 – 75%). Seven patients (21%; 95% CI, 7 – 35%) achieved a complete response (CR) and 12 patients (36%; 95% CI, 20 – 52%) achieved a partial response (PR). Seven of 19 patients with CR/PR are still in remission with a median follow-up of 3 months (range, 2 – 17 months). The median failure-free survival (FFS) was 5 months (range, 2 – 17 months). The median overall survival (OS) for the entire group was 9 months (range, 0.1 – 77 months). There was a significant difference in OS between responders and nonresponders after CMC therapy (log rank test, P = 0.015). When different disease status before CMC treatment was considered, a trend toward longer survival of recurrent patients was observed (log rank test, P = 0.08). Grade 3 – 4 neutropenia developed in 14 (39%) patients, and 16 episodes (15%) of grade 3 – 4 infections were observed. Grade 3 – 4 thrombocytopenia or anemia was seen in 9 patients (25%) and 10 patients (28%), respectively. The results of our study show that the CMC regimen is effective salvage therapy with acceptable toxicity in heavily pretreated patients with NHL including MCL and DLBCL.

Toward personalized therapy for chronic lymphocytic leukemia: DSC and cDNA microarray assessment of two cases.

The differences in clinical course of chronic lymphocytic leukemia could have an impact on variations in a patient’s response to therapy. Our published results revealed that thermal transition (95 ± 5°C) in differential scanning calorimetry profiles appear to be characteristic for the advanced stage of CLL. Moreover, a decrease/loss of this transition in nuclei from leukemic cells exposed to drugs ex vivo could indicate their diverse efficacy. It seems that the lack of changes in thermal profile could predict patient’s drug resistance. In this study, we demonstrate the results obtained after drug treatment of leukemic cells by calorimetry, apoptosis-related parameters involved in expression of genes using cDNA microarray and western blot. These data were compared with the patients’ clinical parameters before and after RCC therapy (rituximab + cladribine + cyclophosphamide). The complementary analysis of studied cases with opposite clinical response (CR or NR) revealed a strong relationship between clinical data, differences in thermal scans and apoptosis-related gene expression. We quantified expression of eight of apoptosis-related 89 genes, i.e., NOXA, PUMA, APAF1, ESRRBL1, CASP3, BCL2, BCL2A1 and MCL1. Particular differences in NOXA and BCL2 expression were revealed. NOXA expression in cells of patients who achieved a complete response to RCC therapy was 0.44 times higher in comparison to control ones. Interestingly, in the case of patients who did not respond to immunotherapy, NOXA expression was highly downregulated (RQ = 4.39) as compared with untreated cells. These results were confirmed by distinct cell viability, protein expression as well as by differences in calorimetry profiles.

Changes in the apoptotic gene expression profile in CLL patients treated with rituximab combined with cladribine and cyclophosphamide-preliminary results

The study was aimed to investigate modifications of apoptotic gene expression profile by microarray technique in 10 patients with chronic lymphocytic leukemia by treatment with rituximab, cladribine and cyclophosphamide (RCC) according to IGHV mutational status. The TaqMan Low Density Array for 96 gene transcripts was used. Those modifications followed two distinctive patterns largely overlapping the IGHV mutational status. In the IGHV-mutated group, the expression of many proapoptotic genes increased after treatment as compared to initial value. Our results suggest that RCC drugs may act through influence on the expression of some apoptosis-involved genes dependently on the IGVH mutational status.