Impact of bone marrow stromal cells on Bcl-2 family members in chronic lymphocytic leukemia

Abstract Contact between chronic lymphocytic leukemia (CLL) cells and accessory stromal cells in tissue microenvironments is considered to play a major role in regulating CLL cell survival and disease progression. Stromal cells of various origins and species, and variable stromal-CLL cell ratios have been used in the past to study CLL-stromal cell interactions and to assess cell-adhesion mediated drug resistance (CAM-DR). Because of the heterogeneity of the currently used in vitro systems to study CLL-MSC interactions, and the importance of these co-culture systems for development and testing of novel agents, we tested a panel of murine and human MSC lines for their capacities to support CLL cell survival and CAM-DR, using various CLL-MSC ratios and fludarabine (F-ara-A) to induce CLL cell apoptosis. We tested four murine, non-transformed MSC lines derived from bone marrow: M210B4, KUM4, ST-2 and KUSA-H1. Also, we tested three human transformed cell lines: Stroma-NKtert, derived from bone marrow and immortalized by human telomerase reverse transcriptase (hTERT), UE6E7-T2 derived from bone marrow and transformed with human papilloma viruses (HPV) E6, E7 and hTERT, and UCB408E6E7Tert33 derived from umbilical cord blood and transformed with hTERT and HPV E6, E7. CLL cells were isolated from peripheral blood of untreated patients and each cell line was tested with at least three different patients according to the following protocol: viability of CLL was tested after 24, 48 and 72 hours by flow cytometry after staining with DiOC6 and propidium iodide. The following conditions were assayed on each of the MSC lines: CLL cells in suspension culture, CLL cells in suspension culture with 10 mM F-ara-A, CLL cells in co-culture with MSC, and CLL cells in co-culture with MSC and with 10 mM F-ara-A. Firstly, we performed titration experiments in order to identify the most appropriate ratio between stromal and CLL cells, using CLL-MSC ratios of 5:1, 10:1, 20:1, 50:1 and 100:1. We found a decline in MSC-derived CLL cell protection at the highest ratio of 100:1, suggesting that ratios of 50:1 or lower provide optimal conditions for in vitro assays. Results shown in Table 1 were assayed using a 20:1 ratio and represented relative viabilities when compared to untreated controls (mean±SEM). Regarding the protective effect of different MSC, we found that all MSC lines demonstrated remarkable protection of CLL cells from spontaneous and F-ara-A-induced apoptosis. We also found that stromal cells that had round shape morphology and easily formed confluent monolayer (M210B4, KUSA-H1, Stroma-NKTert) showed more prolonged protective effect in comparison to cell lines with more spindle shaped morphology (ST-2, KUM4, UE6E7-T2). The failure of UE6E7-T2 and UCB408E6E7Tert33 to demonstrate long-term protection of CLL cells could be related to their own sensitivity to F-ara-A. In this comparative study we demonstrated that both murine and human MSC provide substantial and comparable levels of protection from spontaneous and drug-induced apoptosis. CLL:MSC ratios of 50:1 or lower can be considered ideal for co-culture experiments. Further experiments have to be done to determine the levels of MSC-derived protection in a larger series of CLL samples and in different laboratories for validation. Collectively, in these co-culture assays we can study CLL-MSC interactions and CLL drugs under more standardized conditions that may allow us to evaluate the efficacy of new treatments that target the CLL microenvironment. Time points 24 hours 48 hours 72 hours +Flu + MSC + MSC +Flu +Flu + MSC + MSC +Flu +Flu +MSC + MSC +Flu M210B4 85.2±2.4 117.2±5.0 110.5±4.9 30.8±12.6 138.1±9.5 113.0±2.2 5.2±3.1 138.1±5.1 120.4±3.4 ST-2 93.6±3.0 99.9±2.6 103.1±0.5 51.6±9.4 111.9±2.6 89.8±8.7 13.9±6.3 112.6±5.7 87.0±16.4 KUM-4 93.6±3.0 106.4±1.8 104.2±1.9 51.6±9.4 112.4±2.6 100.8±2.8 13.9±6.3 111.8±6.7 88.5±11.4 KUSA-H1 79.4±7.4 125.1±3.7 118.2±2.0 33.9±10.9 136.0±3.6 107.2±7.0 11.3±6.1 133.6±5.4 84.9±7.6 Stroma-NKTert 79.3±7.0 118.6±7.0 111.0±7.0 30.5±9.5 130.7±9.5 115.6±8.0 7.1±4.3 133.0±11.5 122.7±9.0 UE6E7-T2 79.3±7.0 113.4±3.9 109.3±3.0 30.5±9.5 118.4±4.8 85.0±7.1 7.1±4.3 119.2±6.9 51.0±10.1 UCB408 E6E7Tert33 81.5±7.2 120.2±5.4 111.8±2.7 36.7±9.4 123.7±6.3 86.7±7.7 8.5±6.7 119.7±6.1 50.8±13.0 Table 1. Flu: fludarabine (10mM/ml), MSC: marrow stromal cells

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CHIP regulates bone mass by targeting multiple TRAF family members in bone marrow stromal cells

Bone Research ◽

10.1038/s41413-018-0010-2 ◽

2018 ◽

Vol 6 (1) ◽

Cited By ~ 10

Author(s):

Tingyu Wang ◽

Shan Li ◽

Dan Yi ◽

Guang-Qian Zhou ◽

Zhijie Chang ◽

...

Keyword(s):

Bone Marrow ◽

Bone Mass ◽

Stromal Cells ◽

Bone Marrow Stromal Cells ◽

Family Members ◽

Marrow Stromal Cells

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The Involvement of NF-κB Subunits in the Interaction Between CLL-B Cells and Bone Marrow Stromal Cells

Blood ◽

10.1182/blood.v118.21.4590.4590 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4590-4590

Author(s):

Aining Sun ◽

Guo Feng ◽

Jingjing Xu ◽

Wenjuan Wang ◽

Wu Depei

Keyword(s):

Bone Marrow ◽

B Cells ◽

Mrna Expression ◽

Stromal Cells ◽

Bone Marrow Stromal Cells ◽

Family Members ◽

Proteasome Inhibitors ◽

Marrow Stromal Cells ◽

Protein Levels ◽

Relative Mrna Expression

Abstract Abstract 4590 Objective: To investigate the function of NF-κB signaling pathway in the interaction between chronic lymphocytic leukemia B cells and bone marrow stromal cells. Method: The expression of NF-κB family members at mRNA and protein levels were examined by quantitative RT-PCR and Western bloting analyses individualy, and the differences between CLL-human bone marrow stromal cell (hBMSC) and non-CLL-hBMSC were investigated with the methods above. Cell death was measured by flow cytometry analysis after B-CLL cells were co-cultured with hBMSC and treated with proteasome inhibitors. The changes of NF-κB expression at the protein levels were examined by Western bloting after co-culture experiment. Result: The expression of NF-κB family members turned out to be heterogeneous at both mRNA and protein levels in B-CLL cells, and the members demonstrated a different κB-DNA binding activities. The mRNA expression of NF-κB family members in B-CLL cells was shown at a remarkable higher level than that of the controls. The relative mRNA expression of relA was 0.0214±0.012, whereas it was 0.0130±0.012 for the controls of CD19 positive cells. The relative mRNA expression of p50 and p52 were 66.0860±21.649 and 0.0208±0.011 respectively, and the corresponding expression of CD19 positive cells were 24.8440±9.749 and 0.0065±0.002. The differences were statistically significant. There was no notable difference between CLL-hBMSC and Non-CLL-hBMSC. hBMSC protected B-CLL cells against the proteasome inhibitors and facilitated the survival of B-CLL cells. Conclusion: NF-κB expression is heterogeneous in bone marrow B-CLL cells. There is no significant difference between CLL-hBMSC and non-CLL-hBMSC. hBMSC can protect the survival of B-CLL cells dependending on the endogenous NF-κB activity. hBMSC can increase the drug resistance of B-CLL cells to proteasome inhibitors. Disclosures: No relevant conflicts of interest to declare.

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