REDOX BALANCE AS THE CRITERION FOR PERSONIFIED REGISTRATION OF RESPONSE FROM B-CLL CELLS TO THERAPY
Author(s): ,
Yuliya Harmaza
Affiliations:
Laboratory of Medical Biophysics,Institute of Biophysics and Cell Engineering,Minsk,Belarus
,
Alexander Tamashevski
Affiliations:
Laboratory of Medical Biophysics,Institute of Biophysics and Cell Engineering,Minsk,Belarus
,
Vadim Pasiukov
Affiliations:
Laboratory of multidrug resistance mechanisms,Republican Scientific and Practical Center for Transfusiology and Medical Biotechnologies,Minsk,Belarus
Ekaterina Slobozhanina
Affiliations:
Laboratory of Medical Biophysics,Institute of Biophysics and Cell Engineering,Minsk,Belarus
(Abstract release date: 05/14/20) EHA Library. Harmaza Y. 06/12/20; 297817; PB1901
Dr. Yuliya Harmaza
Dr. Yuliya Harmaza
Contributions
Abstract

Abstract: PB1901

Type: Publication Only

Background
The laboratory component of a personalization therapy involves application not only the initial structural features of cells (e.g. mutations) or cell survival after contact with antitumor drugs in vitro. Obviously, expanding the range of predictive diagnostic technologies can help to predict the response of organism to therapy in order to select an adequate treatment strategy and monitor it. It is known that oxidative stress plays a special role in the implementation of the toxic effect in leukemia cells due to the variability of cytosolic reactive oxygen species (ROS) level and the metabolic characteristics of antitumor drugs. Moreover, there are the experimental data about the close relationship between tumor progression and cellular redox balance, which plays a key role in the protective reaction of cells to exposure antitumor agents.

Aims
To evaluate the redox state of patients with chronic B-lymphocytic leukemia (B-CLL) after exposure to drugs used in the treatment of leukemia and compare with a change in their viability in order to identify a criterion suitable for personified registration of cell responses to therapy.

Methods
The group of patients with B-CLL according to inclusion and exclusion criteria included 30 people. Immunophenotyping for the percentage of CD5+CD19+ cells allowed us to distinguish 2 stable subgroups: I subgroup (n=10), the percentage of CD5+CD19+ cells was 3.1±2.5% (remission stage) and II subgroup (n=20), in which the number of CD5+CD19+ cells was 82.1±16.3% (patients with diagnosed B-CLL before therapy). The level of ROS in B-CLL lymphocytes was determined using a fluorescent probe CM-H2DCFDA. PMBC viability was assessed using MTT test. Next drugs: fludarabel (Flu), vincristine (Vincr), imatinib (Imat), dexamethasone (Dex), in concentrations close to therapeutic were used. All measurements were performed on a plate spectrophotometer and a FACScanto II flow cytometer (BD).

Results
A correlation analysis between the percentage of CD5+CD19+ cells and their sensitivity to the investigated antitumor agents revealed a statistically significant inverse relationship (rs from -0.87 to -0.91, with p from 0.0000003 to 0.000005), which indicates the effectiveness of the selected drugs in relation to a subpopulation of CD5+CD19+. After exposure of studied therapeutic agents on lymphocytes of I subgroup B-CLL patients change in cellular ROS level was discoved compared to intact cells (control). In the II subgroup of B-CLL patients, ROS level also increased after exposure to drugs (except Flu). Moreover, the statistical analysis revealed more significant changes incellular redox balance in II subgroup of B-CLL patients in comparisson with I subgroup after exposure to the investigated drugs. It was revealed that cell viability in both subgroups of B-CLL patients was a statistically significant decrease in comparison with the control. So, for I subgroup theviability reduction for all studied drugs was on 5-15% relative to the control. Meantime in the II subgroup - on 30-60%. This result demonstrates that cells of patients with B-CLL in remission are less sensitive to the studied drugs than leukemia cells before therapy.

Conclusion
Thus, significant variability of the individual B-CLL cells sensitivity was found under exposion to drugs in concentrations close to therapeutic, which indicates about necessity taking into account the individual sensitivity of leukemia cells to chemotherapy ex vivo. So, a change in their redox balance can be used as a criterion for the possibility of a personified accounting of the B-CLL patient’s cell responses to therapy.

Session topic: 05. Chronic lymphocytic leukemia and related disorders - Biology & Translational Research

Keyword(s): B cell chronic lymphocytic leukemia, Therapy

Abstract: PB1901

Type: Publication Only

Background
The laboratory component of a personalization therapy involves application not only the initial structural features of cells (e.g. mutations) or cell survival after contact with antitumor drugs in vitro. Obviously, expanding the range of predictive diagnostic technologies can help to predict the response of organism to therapy in order to select an adequate treatment strategy and monitor it. It is known that oxidative stress plays a special role in the implementation of the toxic effect in leukemia cells due to the variability of cytosolic reactive oxygen species (ROS) level and the metabolic characteristics of antitumor drugs. Moreover, there are the experimental data about the close relationship between tumor progression and cellular redox balance, which plays a key role in the protective reaction of cells to exposure antitumor agents.

Aims
To evaluate the redox state of patients with chronic B-lymphocytic leukemia (B-CLL) after exposure to drugs used in the treatment of leukemia and compare with a change in their viability in order to identify a criterion suitable for personified registration of cell responses to therapy.

Methods
The group of patients with B-CLL according to inclusion and exclusion criteria included 30 people. Immunophenotyping for the percentage of CD5+CD19+ cells allowed us to distinguish 2 stable subgroups: I subgroup (n=10), the percentage of CD5+CD19+ cells was 3.1±2.5% (remission stage) and II subgroup (n=20), in which the number of CD5+CD19+ cells was 82.1±16.3% (patients with diagnosed B-CLL before therapy). The level of ROS in B-CLL lymphocytes was determined using a fluorescent probe CM-H2DCFDA. PMBC viability was assessed using MTT test. Next drugs: fludarabel (Flu), vincristine (Vincr), imatinib (Imat), dexamethasone (Dex), in concentrations close to therapeutic were used. All measurements were performed on a plate spectrophotometer and a FACScanto II flow cytometer (BD).

Results
A correlation analysis between the percentage of CD5+CD19+ cells and their sensitivity to the investigated antitumor agents revealed a statistically significant inverse relationship (rs from -0.87 to -0.91, with p from 0.0000003 to 0.000005), which indicates the effectiveness of the selected drugs in relation to a subpopulation of CD5+CD19+. After exposure of studied therapeutic agents on lymphocytes of I subgroup B-CLL patients change in cellular ROS level was discoved compared to intact cells (control). In the II subgroup of B-CLL patients, ROS level also increased after exposure to drugs (except Flu). Moreover, the statistical analysis revealed more significant changes incellular redox balance in II subgroup of B-CLL patients in comparisson with I subgroup after exposure to the investigated drugs. It was revealed that cell viability in both subgroups of B-CLL patients was a statistically significant decrease in comparison with the control. So, for I subgroup theviability reduction for all studied drugs was on 5-15% relative to the control. Meantime in the II subgroup - on 30-60%. This result demonstrates that cells of patients with B-CLL in remission are less sensitive to the studied drugs than leukemia cells before therapy.

Conclusion
Thus, significant variability of the individual B-CLL cells sensitivity was found under exposion to drugs in concentrations close to therapeutic, which indicates about necessity taking into account the individual sensitivity of leukemia cells to chemotherapy ex vivo. So, a change in their redox balance can be used as a criterion for the possibility of a personified accounting of the B-CLL patient’s cell responses to therapy.

Session topic: 05. Chronic lymphocytic leukemia and related disorders - Biology & Translational Research

Keyword(s): B cell chronic lymphocytic leukemia, Therapy

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