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Targeting cholesterol synthesis increases chemoimmuno-sensitivity in chronic lymphocytic leukemia cells.

Benakanakere I, Johnson T, Sleightholm R, Villeda V, Arya M, Bobba R, Freter C, Huang C - Exp Hematol Oncol (2014)

Bottom Line: We found that MEC-2 cells treated with cholesterol lowering agents (BIBB-515, YM-53601 or TAK-475) reduced 20% of total cellular cholesterol levels, but also significantly promoted CD-20 surface expression.More importantly, these cholesterol lowering agents also significantly enhanced chemoimmuno-sensitivity of the PBMCs from CLL patients.These results provide a novel strategy which could be applied to CLL treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Hematology/Oncology, Department of Medicine, School of Medicine, University of Missouri, Columbia, MO 65212, USA.

ABSTRACT

Background: Cholesterol plays an important role in cancer development, drug resistance and chemoimmuno-sensitivity. Statins, cholesterol lowering drugs, can induce apoptosis, but also negatively interfere with CD-20 and rituximab-mediated activity. Our goal is to identify the alternative targets that could reduce cholesterol levels but do not interfere with CD-20 in chemo immunotherapy of chronic lymphocytic leukemia (CLL).

Methods: MEC-2 cells, a CLL cell line, and the peripheral blood mononuclear cells (PBMCs) from CLL patients were treated with cholesterol lowering agents, and analyzed the effect of these agents on cholesterol levels, CD-20 expression and distribution, and cell viability in the presence or absence of fludarabine, rituximab or their combinations.

Results: We found that MEC-2 cells treated with cholesterol lowering agents (BIBB-515, YM-53601 or TAK-475) reduced 20% of total cellular cholesterol levels, but also significantly promoted CD-20 surface expression. Furthermore, treatment of cells with fludarabine, rituximab or their combinations in the presence of BIBB-515, YM-53601 or TAK-475 enhanced MEC-2 cell chemoimmuno-sensitivity measured by cell viability. More importantly, these cholesterol lowering agents also significantly enhanced chemoimmuno-sensitivity of the PBMCs from CLL patients.

Conclusion: Our data demonstrate that BIBB-515, YM53601 and TAK-475 render chemoimmuno-therapy resistant MEC-2 cells sensitive to chemoimmuno-therapy and enhance CLL cell chemoimmuno-sensitivity without CD-20 epitope presentation or its downstream signaling. These results provide a novel strategy which could be applied to CLL treatment.

No MeSH data available.


Related in: MedlinePlus

Effect of chemoimmuno-therapeutic drugs on MEC-2 cell viability and apoptosis. A) MEC-2 cells were treated with different concentration of fludarabine (Flu) or rituximab (Rit) (n = 16) for 3 days, and cell viability was analyzed by MTT assay. B) MEC-2 cells were treated with 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days, and analyzed cell viability by either MTT assay (n = 16) or Trypan blue staining (n = 4) and DNA fragmentation (C). The DNA fragmentation represents three experiments performed with duplicate samples. The values of the treated groups were statistically different from the untreated control group. Con: control. *P < 0.05. **P < 0.01.
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Figure 1: Effect of chemoimmuno-therapeutic drugs on MEC-2 cell viability and apoptosis. A) MEC-2 cells were treated with different concentration of fludarabine (Flu) or rituximab (Rit) (n = 16) for 3 days, and cell viability was analyzed by MTT assay. B) MEC-2 cells were treated with 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days, and analyzed cell viability by either MTT assay (n = 16) or Trypan blue staining (n = 4) and DNA fragmentation (C). The DNA fragmentation represents three experiments performed with duplicate samples. The values of the treated groups were statistically different from the untreated control group. Con: control. *P < 0.05. **P < 0.01.

Mentions: To investigate whether chemoimmuno-sensitivity of CLL cells could be altered, we chose MEC-2 cells, a fludarabine- and rituximab-insensitive CLL cell line. Cell viability, which indicates complement-dependent cytotoxicity that contributes significantly to clinical efficacy, was assessed by the MTT assay or Trypan blue staining after treatment. Figure 1A illustrates the dose effect of either fludarabine or rituximab on MEC-2 cell viability. At lower concentrations (<10 μM fludarabine or 10 μg/ml rituximab), fludarabine and rituximab have similar patterns in response to reduce cell viability. Higher concentrations demonstrate fludarabine cytotoxicity. Two different methods (MTT assay and Trypan blue staining) show similar results with exposure of MEC-2 cells to 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days. They caused about 28%, 25% or 50% reduction of cell viability, respectively (Figure 1B). To further determine whether the reduction of cell viability in drug-treated cells is due to cell growth arrest or apoptosis, we analyzed DNA fragmentation as a result of the signature events of apoptosis. Figure 1C clearly shows that treatment of MEC-2 cells with the chemoimmuno-therapeutic drugs increases DNA fragmentation. These results demonstrate that chemo- or immuno-therapeutic drugs induce MEC-2 apoptosis.


Targeting cholesterol synthesis increases chemoimmuno-sensitivity in chronic lymphocytic leukemia cells.

Benakanakere I, Johnson T, Sleightholm R, Villeda V, Arya M, Bobba R, Freter C, Huang C - Exp Hematol Oncol (2014)

Effect of chemoimmuno-therapeutic drugs on MEC-2 cell viability and apoptosis. A) MEC-2 cells were treated with different concentration of fludarabine (Flu) or rituximab (Rit) (n = 16) for 3 days, and cell viability was analyzed by MTT assay. B) MEC-2 cells were treated with 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days, and analyzed cell viability by either MTT assay (n = 16) or Trypan blue staining (n = 4) and DNA fragmentation (C). The DNA fragmentation represents three experiments performed with duplicate samples. The values of the treated groups were statistically different from the untreated control group. Con: control. *P < 0.05. **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4231203&req=5

Figure 1: Effect of chemoimmuno-therapeutic drugs on MEC-2 cell viability and apoptosis. A) MEC-2 cells were treated with different concentration of fludarabine (Flu) or rituximab (Rit) (n = 16) for 3 days, and cell viability was analyzed by MTT assay. B) MEC-2 cells were treated with 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days, and analyzed cell viability by either MTT assay (n = 16) or Trypan blue staining (n = 4) and DNA fragmentation (C). The DNA fragmentation represents three experiments performed with duplicate samples. The values of the treated groups were statistically different from the untreated control group. Con: control. *P < 0.05. **P < 0.01.
Mentions: To investigate whether chemoimmuno-sensitivity of CLL cells could be altered, we chose MEC-2 cells, a fludarabine- and rituximab-insensitive CLL cell line. Cell viability, which indicates complement-dependent cytotoxicity that contributes significantly to clinical efficacy, was assessed by the MTT assay or Trypan blue staining after treatment. Figure 1A illustrates the dose effect of either fludarabine or rituximab on MEC-2 cell viability. At lower concentrations (<10 μM fludarabine or 10 μg/ml rituximab), fludarabine and rituximab have similar patterns in response to reduce cell viability. Higher concentrations demonstrate fludarabine cytotoxicity. Two different methods (MTT assay and Trypan blue staining) show similar results with exposure of MEC-2 cells to 10 μM fludarabine, 10 μg/ml rituximab or their combinations for 3 days. They caused about 28%, 25% or 50% reduction of cell viability, respectively (Figure 1B). To further determine whether the reduction of cell viability in drug-treated cells is due to cell growth arrest or apoptosis, we analyzed DNA fragmentation as a result of the signature events of apoptosis. Figure 1C clearly shows that treatment of MEC-2 cells with the chemoimmuno-therapeutic drugs increases DNA fragmentation. These results demonstrate that chemo- or immuno-therapeutic drugs induce MEC-2 apoptosis.

Bottom Line: We found that MEC-2 cells treated with cholesterol lowering agents (BIBB-515, YM-53601 or TAK-475) reduced 20% of total cellular cholesterol levels, but also significantly promoted CD-20 surface expression.More importantly, these cholesterol lowering agents also significantly enhanced chemoimmuno-sensitivity of the PBMCs from CLL patients.These results provide a novel strategy which could be applied to CLL treatment.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Hematology/Oncology, Department of Medicine, School of Medicine, University of Missouri, Columbia, MO 65212, USA.

ABSTRACT

Background: Cholesterol plays an important role in cancer development, drug resistance and chemoimmuno-sensitivity. Statins, cholesterol lowering drugs, can induce apoptosis, but also negatively interfere with CD-20 and rituximab-mediated activity. Our goal is to identify the alternative targets that could reduce cholesterol levels but do not interfere with CD-20 in chemo immunotherapy of chronic lymphocytic leukemia (CLL).

Methods: MEC-2 cells, a CLL cell line, and the peripheral blood mononuclear cells (PBMCs) from CLL patients were treated with cholesterol lowering agents, and analyzed the effect of these agents on cholesterol levels, CD-20 expression and distribution, and cell viability in the presence or absence of fludarabine, rituximab or their combinations.

Results: We found that MEC-2 cells treated with cholesterol lowering agents (BIBB-515, YM-53601 or TAK-475) reduced 20% of total cellular cholesterol levels, but also significantly promoted CD-20 surface expression. Furthermore, treatment of cells with fludarabine, rituximab or their combinations in the presence of BIBB-515, YM-53601 or TAK-475 enhanced MEC-2 cell chemoimmuno-sensitivity measured by cell viability. More importantly, these cholesterol lowering agents also significantly enhanced chemoimmuno-sensitivity of the PBMCs from CLL patients.

Conclusion: Our data demonstrate that BIBB-515, YM53601 and TAK-475 render chemoimmuno-therapy resistant MEC-2 cells sensitive to chemoimmuno-therapy and enhance CLL cell chemoimmuno-sensitivity without CD-20 epitope presentation or its downstream signaling. These results provide a novel strategy which could be applied to CLL treatment.

No MeSH data available.


Related in: MedlinePlus