Contributions
Abstract: PB2330
Type: Publication Only
Background
Bone marrow (BM) is not affected in most patients with Diffuse Large B-cell Lymphoma (DLBCL). In the onset of the disease, histological examination shows no changes in the BM stroma. Patients, depending on IPI, are treated either by R±CHOP courses or by the program R±mNHL-BFM-90. Immediately after the course of treatment and in the distant periods (6-12 years), changes in the bone marrow stroma are observed. There is no data about alterations in stromal precursor cells (multipotent mesenchymal stromal cells /MSCs/ and colony forming unit fibroblasts /CFU-F/).
Aims
The aim of the study was to investigate the changes in MSCs and CFU-F from the BM of patients with DLBCL at the onset of the disease and 6-12 years after treatment.
Methods
The study included 10 patients at the onset of the disease, 20 after treatment with R±mNHL-BFM-90 and 11 with R±CHOP. In all patients BM was taken after informed consent. From the BM, MSCs were isolated by the standard method and the concentration of CFU-F was determined. The relative expression level (REL) of various genes in MSCs was determined by real-time PCR. As a control 31 MSC samples from the BM of healthy donors selected for each group of patients according to age were used.
Results
DLBCL patients’ stromal progenitor cells differ from those of donors. In primary patients, the concentration of CFU-F in the BM is reduced by 30%. After R±CHOP, it is 2 times reduced compared with donors and 1.6 times with primary patients. After R±mNHL-BFM-90 it is 1.5 times higher than that of donors and 2 times higher than in patients after R±CHOP. The total cellular production of MSCs in primary patients is 2.3 times higher than that of donors. Many years after R±CHOP, it almost reaches the level of donors, after R±mNHL-BFM-90, it remains 1.7 times higher. Activation of the stromal microenvironment occurs. The expression of FGF2 in MSCs is reduced in primary patients and years after treatment. The REL of FGFR1 is also lower in patients compared to donors. The REL of FGFR2 is doubled in primary patients compared to donors and remains significantly increased years after the treatment. The REL of ICAM1 and MMP2, involved in the adhesion of hematopoietic cells, are reduced by 2 times, which indicates irreversible changes in the ability to maintain hematopoiesis irrespective of the treatment. Osteopontin (SPP1) regulates the quiescent state of hematopoietic stem cells (HSC) in a niche. In primary patients, the REL of this gene is increased almost 3 times in comparison with donors. In patients after R±CHOP, it decreases, and after treatment with R±mNHL-BFM-90, it rises even more. Apparently patients MSCs react to the lymphoid tumor and use the mechanisms of HSCs protection. The level of osteocalcin (BGLAP) expression is reduced in primary patients and remains low for years regardless of the treatment. Patients bone tissue suffers and these changes are not restored. The REL of interleukin 6 (IL6) is reduced in primary patients by 3.5 times in comparison with donors. Years after chemotherapy, it remains reduced 2 times regardless of the treatment. IL6 is a growth factor for lymphoid cells and simultaneously a pro-inflammatory cytokine. Its decrease can also be attributed to the protective mechanisms used by the MSCs.
Conclusion
Stromal BM precursor cells respond to a lymphoid tumor even if there is no BM involvement. Analysis of all factors shows that many years after treatment, the characteristics of MSCs are only partially restored. Supported by grant from the Russian Foundation for Basic Research, Project № 17-00-00170
Session topic: 19. Non-Hodgkin lymphoma Biology & Translational Research
Keyword(s): Diffuse large B cell lymphoma, Gene expression, Mesenchymal cells
Abstract: PB2330
Type: Publication Only
Background
Bone marrow (BM) is not affected in most patients with Diffuse Large B-cell Lymphoma (DLBCL). In the onset of the disease, histological examination shows no changes in the BM stroma. Patients, depending on IPI, are treated either by R±CHOP courses or by the program R±mNHL-BFM-90. Immediately after the course of treatment and in the distant periods (6-12 years), changes in the bone marrow stroma are observed. There is no data about alterations in stromal precursor cells (multipotent mesenchymal stromal cells /MSCs/ and colony forming unit fibroblasts /CFU-F/).
Aims
The aim of the study was to investigate the changes in MSCs and CFU-F from the BM of patients with DLBCL at the onset of the disease and 6-12 years after treatment.
Methods
The study included 10 patients at the onset of the disease, 20 after treatment with R±mNHL-BFM-90 and 11 with R±CHOP. In all patients BM was taken after informed consent. From the BM, MSCs were isolated by the standard method and the concentration of CFU-F was determined. The relative expression level (REL) of various genes in MSCs was determined by real-time PCR. As a control 31 MSC samples from the BM of healthy donors selected for each group of patients according to age were used.
Results
DLBCL patients’ stromal progenitor cells differ from those of donors. In primary patients, the concentration of CFU-F in the BM is reduced by 30%. After R±CHOP, it is 2 times reduced compared with donors and 1.6 times with primary patients. After R±mNHL-BFM-90 it is 1.5 times higher than that of donors and 2 times higher than in patients after R±CHOP. The total cellular production of MSCs in primary patients is 2.3 times higher than that of donors. Many years after R±CHOP, it almost reaches the level of donors, after R±mNHL-BFM-90, it remains 1.7 times higher. Activation of the stromal microenvironment occurs. The expression of FGF2 in MSCs is reduced in primary patients and years after treatment. The REL of FGFR1 is also lower in patients compared to donors. The REL of FGFR2 is doubled in primary patients compared to donors and remains significantly increased years after the treatment. The REL of ICAM1 and MMP2, involved in the adhesion of hematopoietic cells, are reduced by 2 times, which indicates irreversible changes in the ability to maintain hematopoiesis irrespective of the treatment. Osteopontin (SPP1) regulates the quiescent state of hematopoietic stem cells (HSC) in a niche. In primary patients, the REL of this gene is increased almost 3 times in comparison with donors. In patients after R±CHOP, it decreases, and after treatment with R±mNHL-BFM-90, it rises even more. Apparently patients MSCs react to the lymphoid tumor and use the mechanisms of HSCs protection. The level of osteocalcin (BGLAP) expression is reduced in primary patients and remains low for years regardless of the treatment. Patients bone tissue suffers and these changes are not restored. The REL of interleukin 6 (IL6) is reduced in primary patients by 3.5 times in comparison with donors. Years after chemotherapy, it remains reduced 2 times regardless of the treatment. IL6 is a growth factor for lymphoid cells and simultaneously a pro-inflammatory cytokine. Its decrease can also be attributed to the protective mechanisms used by the MSCs.
Conclusion
Stromal BM precursor cells respond to a lymphoid tumor even if there is no BM involvement. Analysis of all factors shows that many years after treatment, the characteristics of MSCs are only partially restored. Supported by grant from the Russian Foundation for Basic Research, Project № 17-00-00170
Session topic: 19. Non-Hodgkin lymphoma Biology & Translational Research
Keyword(s): Diffuse large B cell lymphoma, Gene expression, Mesenchymal cells