Changes in leukemic cell nuclei revealed by differential scanning calorimetry

Personalized therapy tests for the monitoring of chronic lymphocytic leukemia development

There is individual variation in the course of disease development and response to therapy of patients with chronic lymphocytic leukemia (CLL). Novel treatment options for CLL include a new generation of purine analogs, antibodies and inhibitors of specific cell signaling pathways, which typically induce apoptosis or necrosis. A prospective analysis of patient blood samples revealed that a combination of four tests allowed the most appropriate and effective type of treatment to be selected prior to drug administration, and for the analysis of leukemic cell sensitivity to anticancer drug(s) during disease development. The comparative analysis of blood from the stable and progressive form of CLL in an individual patient revealed diversity in the response to anticancer agents. CLL peripheral blood mononuclear cells were incubated with cladribine + mafosfamide (CM), fludarabine + mafosfamide, CM + rituximab, rituximab alone (Rit) or kinetin riboside (RK). A combination of cell viability, differential scanning calorimetry (DSC) profiles of nuclear preparations and poly(ADP-ribose) polymerase 1 (PARP-1) protein expression analysis of the leukemic cells was performed to evaluate the anticancer effects of the tested agents during CLL development. The results of the present study indicate that such studies are effective in determining the most appropriate anticancer drug and could monitor disease progression on an individual level. In addition, the results of the current study suggest that CLL progression leads to diversification of the cellular drug response. The most efficient apoptosis inducer for the patient was purine analog RK when the disease was stable, while the CM combination was the most effective agent for the progressive form of disease.

Relationship between in vitro drug sensitivity and clinical response of patients to treatment in chronic lymphocytic leukemia

To improve the efficacy of therapeutic options in chronic lymphocytic leukemia (CLL) an in vitro system to determine the response of mononuclear blood cells from blood of patients was elaborated. The study combines four approaches, i.e., cell viability, apoptosis rate, differential scanning calorimetry (DSC), and immunoblotting to develop personalized therapy protocols based on the cell sensitivity to drug exposure of individual CLL patients. The complementary analyses were performed on 28 peripheral blood samples from previously untreated CLL patients before therapy. The induction and progress of apoptosis in CLL cells exposed in vitro to purine analogs combined with mafosfamide, i.e., cladribine + mafosfamide (CM) and fludarabine + mafosfamide (FM) were assessed using the above approaches. The changes in thermal profiles (decrease/loss of transition at 95±5˚C) coincided with an accumulation of apoptotic cells, a decrease in the number of viable cells, and differences in the expression of the apoptosis‑related protein PARP‑1. No significant changes were observed in the thermal profiles of nuclei isolated from CLL cells resistant to the treatment. The complementary assays revealed a strong relationship between both the in vitro sensitivity of leukemia cells to drugs and the clinical response of the patients, determined usually after the sixth course of treatment (after ~6 months of therapy). As a summary of studies followed by complementary tests, our findings demonstrate the value of in vitro exposure of CLL cell samples to drugs intended to treat CLL patients, before their administration in order to recommend the most suitable and effective therapy for individual patients.

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.

Calorimetric study as a potential test for choosing treatment of B-cell chronic lymphocytic leukemia

Differential scanning calorimetry (DSC) and complementary techniques were utilized to evaluate the sensitivity of B-cell chronic lymphocytic leukemia (B-CLL) cell samples in vitro exposed to cladribine or fludarabine in combination with mafosfamide. Mafosfamide, the active in vitro form of cyclophosphamide with both purine analogs produced the cytotoxic effect on mononuclear cell probes, however, to a different degree. Our results indicated that higher sensitivity of examined leukemic cell samples to the used drug combinations was usually accompanied by a marked decrease or even a complete loss of thermal transition at 95+/-3 degrees C in DSC scans of nuclear preparations as well as by more significant reduction of cell viability, higher extent of DNA damage estimated by the comet assay and by dropping/disappearance of anti-apoptotic protein Mcl-1 in comparison with untreated cells. We have also observed that the reduction of transition at 95+/-3 degrees C in thermal scans of nuclear preparations isolated from blood of B-CLL randomized patients who showed response to cladribine or fludarabine combined with cyclophosphamide, i.e., CC and FC, respectively, corresponded with the decrease or disappearance of anti-apoptotic proteins Bcl-2 and/or Mcl 1. In conclusion, these in vitro and in vivo studies revealed that quick DSC technique, usually supplemented by other methods, is a potent tool to distinguish efficacy of B-CLL treatment and could be helpful in choosing the most effective manner of treatment for this type of leukemia.