[Efficacy of a bendamustine and rituximab combination in first-line therapy for chronic lymphocytic leukemia: Results of the BEN-001 study]

AIM

To evaluate the efficacy and safety of the BR regimen containing bendamustine in patients with chronic lymphocytic leukemia (CLL) who have not previously received specific therapy.

SUBJECTS AND METHODS

The results of the Russian prospective observational multicenter study BEN-001 (2012-2015) covering 196 CLL patients from 34 centers of the Russian Federation were analyzed. The diagnosis was confirmed by the results of peripheral blood lymphocyte immunophenotyping. A centralized approach was employed to make IGHV gene mutational status analysis, FISH examination, and minimal residual disease according to standardized methods. Quality-of-life (QOL) indicators were estimated using the EQ-5D and FACT-Leu questionnaires. Survival rates were calculated applying by the Kaplan-Meier method.

RESULTS

The patients' median age was 61 years. 41% of patients had a decline in estimated creatinine clearance less than 70 ml/min/1.73 m2. The combination of bendamustine and rituximab could achieve a common response in 83.2% of the patients, including complete remission in 59.7%. Eradication of minimal residual disease was achieved in 23 (27.4%) of 84 patients. Two-year progression-free survival rates were 85.9%. The QOL indicators were noted to be improved during the treatment.

CONCLUSION

The investigation shows the good tolerability of bendamustine when it is used in clinical practice. Due to the high cost of new drugs (ibrutinib, obinutuzumab, ofatumumab, etc.) and toxicity of the FCR regimen, the combination including bendamustine can be the best first-line therapy option for all CLL patients, regardless of their age and comorbidity.

[Murine and human hematopoietic progenitor cultures grown on stromal layers expressing Notch ligands]

The ex vivo maintenance and expansion of hematopoietic stem cells and early progenitors is necessary for the successful treatment of hematopoietic and immune diseases. Multiple attempts to improve the expansion of hematopoietic stem cells (HSCs) by their cultivation in the presence of growth factor cocktails have so far failed. Novel approaches aimed at conserving the earliest precursors in their undifferentiated state are needed. These approaches should take into account local regulatory factors that are present in the HSC microenvironment and the three-dimensional architecture of their niche. In the present study, we compared the effects of two Notch ligands, i.e., Jagged1 and DLL1, on murine and human hematopoiesis in vitro. Our observations indicate that the stromal expression of Notch ligands increases the production of both the total and phenotypically early murine and human hematopoietic cells in the co-culture. On one hand, this study demonstrates the similarity of effects of stromal expression of Notch ligands on murine and human hematopoiesis in vitro. On the other hand, our study revealed a number of cell type and ligand-specific variations that are systematically described below. It seems that the effects of SCF cytokine addition on murine hematopoiesis in vitro depend on the stromal context and are oppositely directed for Jagged1 and DLL1.

[Functional characteristics of the individual genomic condensin binding sites of Saccharomyces cerevisiae using minichromosome mitotic segregation stability model]

Proper chromatin compaction in mitosis (condensation) is required for equal chromosome distribution and precise genetic information inheritance. Protein complex named condensin is responsible for the mitotic condensation, it also individualizes chromosomes, and ensures chromatin separation between sister chromatids in mitosis as well as proper mitotic spindle tension. Mitotic condensin function depends on recognition of the specific binding sites on the chromosome. Mechanism of condensin binding on the individual sites of the mitotic chromosomes, as well as molecular anatomy of these sites remains to be unclear. Even less known is how condensin binding on the individual sites helps separating chromosomes in anaphase. In current paper using minichromosome test, we analyze seven individual condensin binding sites in Saccharomyces cerevisiae found in previous all-genome CHIP on CHIP screening in our lab. This approach allowed us to find out what was the individual contribution of condensin binding sites in securing mitotic stability of the minichromosomes.

[The role of SRC kinase in activation of transcription factor STAT1]

Transcription factor STAT1 (Signal Transducers and Activators of Transcription) takes part in signal transduction from receptors of growth factors and many cytokines, including interferons. In this paper, the role of tyrosinkinases Src and JAK2 was estimated in activation of STAT1 by epidermal growth factor (EGF) and hyperosmotic shock. Using a pharmacological inhibitor of Src kinases CGP77675 and cells with knockout c-src, it was shown that Src activated STAT1 upon stimulation by both epidermal growth factor and hypersomatic shock. In contrast, JAK2 activity exerted no influence on these processes.