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Combination treatment with decitabine and ionizing radiation enhances tumor cells susceptibility of T cells

View Article: PubMed Central - PubMed

ABSTRACT

Decitabine has been found to have anti-metabolic and anti-tumor activities in various tumor cells. Recently, the use of decitabine in combination with other conventional therapies reportedly resulted in improved anti-tumor activity against various tumors. Ionizing radiation (IR) is widely used as a cancer treatment. Decitabine and IR improve immunogenicity and susceptibility of tumor cells to immune cells by up-regulating the expression of various molecules such as major histocompatibility complex (MHC) class I; natural-killer group 2, member D (NKG2D) ligands; and co-stimulatory molecules. However, the effects of combining decitabine and IR therapies are largely unknown. Our results indicate that decitabine or IR treatment upregulates MHC class I, along with various co-stimulatory molecules in target tumor cells. Furthermore, decitabine and IR combination treatment further upregulates MHC class I, along with the co-stimulatory molecules, when compared to the effect of each treatment alone. Importantly, decitabine treatment further enhanced T cell-mediated cytotoxicity and release of IFN- γ against target tumor cells which is induced by IR. Interestingly, decitabine did not affect NKG2D ligand expression or NK cell-mediated cytotoxicity in target tumor cells. These observations suggest that decitabine may be used as a useful immunomodulator to sensitize tumor cells in combination with other tumor therapies.

No MeSH data available.


Related in: MedlinePlus

Effects of treatment with decitabine, ionizing radiation (IR), or their combination on IFN-γ production in T cells against target tumor cells.T cells were co-cultured with decitabine, IR or both treated tumor cells (A549, HCT-116, and HepG2 cells) for 4 h (a). For blockade experiments (b), T cells were co-cultured with combination-treated target tumor cells in the presence of 10 ug/ml anti-CD40, CD80, and/or HLA-A,B,C antibody. Then the cell supernatants were harvested and analyzed by ELISA. Results express the average IFN-γ production ± SD in T cells co-cultured with A549, HCT-116, and HepG2 cells. Experiments were independently performed from five healthy donors. The assay was performed in triplicated each donor. Statistical significance was determined using a one-way ANOVA. #P < 0.05, ##P < 0.005, ###P < 0.0005 (#DAC 0 versus other groups, mIgG versus other groups). *P < 0.05 (*DAC 5 versus other groups). **P < 0.05 (**IR 8 Gy versus DAC 5 + IR 8 Gy). @P < 0.05, @@P < 0.005 (@αCD40 + αCD80 versus αCD40 + αCD80 + αHLA-ABC).
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f4: Effects of treatment with decitabine, ionizing radiation (IR), or their combination on IFN-γ production in T cells against target tumor cells.T cells were co-cultured with decitabine, IR or both treated tumor cells (A549, HCT-116, and HepG2 cells) for 4 h (a). For blockade experiments (b), T cells were co-cultured with combination-treated target tumor cells in the presence of 10 ug/ml anti-CD40, CD80, and/or HLA-A,B,C antibody. Then the cell supernatants were harvested and analyzed by ELISA. Results express the average IFN-γ production ± SD in T cells co-cultured with A549, HCT-116, and HepG2 cells. Experiments were independently performed from five healthy donors. The assay was performed in triplicated each donor. Statistical significance was determined using a one-way ANOVA. #P < 0.05, ##P < 0.005, ###P < 0.0005 (#DAC 0 versus other groups, mIgG versus other groups). *P < 0.05 (*DAC 5 versus other groups). **P < 0.05 (**IR 8 Gy versus DAC 5 + IR 8 Gy). @P < 0.05, @@P < 0.005 (@αCD40 + αCD80 versus αCD40 + αCD80 + αHLA-ABC).

Mentions: Release of immunomodulatory cytokines such as IFN- γ is one of the major functions of anti-tumor immunity. Tumor cells treated with decitabine and IR alone and in combination were co-cultured with T cells, and IFN-γ levels were subsequently determined in the culture supernatants. Treatment with decitabine and IR alone significantly increased IFN-γ production in T cells compared with untreated target tumor cells; furthermore, the decitabine and IR combination treatment significantly increased IFN-γ levels compared with either treatment alone (Fig. 4a). However, there was no significant difference between treatment with decitabine and IR in the production of IFN-γ. To evaluate the effect of treatment with decitabine and IR-induced MHC class I and co-stimulatory molecules expression in the IFN-γ production of T cells, T cells were co-cultured with target tumor cells in the presence of blocking antibody against MHC class I, CD40 and CD80. As shown in Fig. 4b, blocking of the MHC class I and CD80 resulted in a substantial reduction of IFN-γ production against all target tumor cells, but CD40 blockade significantly reduced only in A549 tumor cells. In particular, the combination blockade of MHC class I and co-stimulatory molecules more significantly reduced T cell-mediated IFN-γ production compared with either blockade alone. These results were similar to those observed in the cytotoxicity test and suggest that treatment with decitabine and IR alone and in combination may further improve the susceptibility of tumor cells to T cell-mediated cytotoxicity.


Combination treatment with decitabine and ionizing radiation enhances tumor cells susceptibility of T cells
Effects of treatment with decitabine, ionizing radiation (IR), or their combination on IFN-γ production in T cells against target tumor cells.T cells were co-cultured with decitabine, IR or both treated tumor cells (A549, HCT-116, and HepG2 cells) for 4 h (a). For blockade experiments (b), T cells were co-cultured with combination-treated target tumor cells in the presence of 10 ug/ml anti-CD40, CD80, and/or HLA-A,B,C antibody. Then the cell supernatants were harvested and analyzed by ELISA. Results express the average IFN-γ production ± SD in T cells co-cultured with A549, HCT-116, and HepG2 cells. Experiments were independently performed from five healthy donors. The assay was performed in triplicated each donor. Statistical significance was determined using a one-way ANOVA. #P < 0.05, ##P < 0.005, ###P < 0.0005 (#DAC 0 versus other groups, mIgG versus other groups). *P < 0.05 (*DAC 5 versus other groups). **P < 0.05 (**IR 8 Gy versus DAC 5 + IR 8 Gy). @P < 0.05, @@P < 0.005 (@αCD40 + αCD80 versus αCD40 + αCD80 + αHLA-ABC).
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f4: Effects of treatment with decitabine, ionizing radiation (IR), or their combination on IFN-γ production in T cells against target tumor cells.T cells were co-cultured with decitabine, IR or both treated tumor cells (A549, HCT-116, and HepG2 cells) for 4 h (a). For blockade experiments (b), T cells were co-cultured with combination-treated target tumor cells in the presence of 10 ug/ml anti-CD40, CD80, and/or HLA-A,B,C antibody. Then the cell supernatants were harvested and analyzed by ELISA. Results express the average IFN-γ production ± SD in T cells co-cultured with A549, HCT-116, and HepG2 cells. Experiments were independently performed from five healthy donors. The assay was performed in triplicated each donor. Statistical significance was determined using a one-way ANOVA. #P < 0.05, ##P < 0.005, ###P < 0.0005 (#DAC 0 versus other groups, mIgG versus other groups). *P < 0.05 (*DAC 5 versus other groups). **P < 0.05 (**IR 8 Gy versus DAC 5 + IR 8 Gy). @P < 0.05, @@P < 0.005 (@αCD40 + αCD80 versus αCD40 + αCD80 + αHLA-ABC).
Mentions: Release of immunomodulatory cytokines such as IFN- γ is one of the major functions of anti-tumor immunity. Tumor cells treated with decitabine and IR alone and in combination were co-cultured with T cells, and IFN-γ levels were subsequently determined in the culture supernatants. Treatment with decitabine and IR alone significantly increased IFN-γ production in T cells compared with untreated target tumor cells; furthermore, the decitabine and IR combination treatment significantly increased IFN-γ levels compared with either treatment alone (Fig. 4a). However, there was no significant difference between treatment with decitabine and IR in the production of IFN-γ. To evaluate the effect of treatment with decitabine and IR-induced MHC class I and co-stimulatory molecules expression in the IFN-γ production of T cells, T cells were co-cultured with target tumor cells in the presence of blocking antibody against MHC class I, CD40 and CD80. As shown in Fig. 4b, blocking of the MHC class I and CD80 resulted in a substantial reduction of IFN-γ production against all target tumor cells, but CD40 blockade significantly reduced only in A549 tumor cells. In particular, the combination blockade of MHC class I and co-stimulatory molecules more significantly reduced T cell-mediated IFN-γ production compared with either blockade alone. These results were similar to those observed in the cytotoxicity test and suggest that treatment with decitabine and IR alone and in combination may further improve the susceptibility of tumor cells to T cell-mediated cytotoxicity.

View Article: PubMed Central - PubMed

ABSTRACT

Decitabine has been found to have anti-metabolic and anti-tumor activities in various tumor cells. Recently, the use of decitabine in combination with other conventional therapies reportedly resulted in improved anti-tumor activity against various tumors. Ionizing radiation (IR) is widely used as a cancer treatment. Decitabine and IR improve immunogenicity and susceptibility of tumor cells to immune cells by up-regulating the expression of various molecules such as major histocompatibility complex (MHC) class I; natural-killer group 2, member D (NKG2D) ligands; and co-stimulatory molecules. However, the effects of combining decitabine and IR therapies are largely unknown. Our results indicate that decitabine or IR treatment upregulates MHC class I, along with various co-stimulatory molecules in target tumor cells. Furthermore, decitabine and IR combination treatment further upregulates MHC class I, along with the co-stimulatory molecules, when compared to the effect of each treatment alone. Importantly, decitabine treatment further enhanced T cell-mediated cytotoxicity and release of IFN- &gamma; against target tumor cells which is induced by IR. Interestingly, decitabine did not affect NKG2D ligand expression or NK cell-mediated cytotoxicity in target tumor cells. These observations suggest that decitabine may be used as a useful immunomodulator to sensitize tumor cells in combination with other tumor therapies.

No MeSH data available.


Related in: MedlinePlus