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Combination therapy with local radiofrequency ablation and systemic vaccine enhances antitumor immunity and mediates local and distal tumor regression.

Gameiro SR, Higgins JP, Dreher MR, Woods DL, Reddy G, Wood BJ, Guha C, Hodge JW - PLoS ONE (2013)

Bottom Line: Murine colon carcinoma cells expressing the tumor-associated (TAA) carcinoembryonic antigen (CEA) (MC38-CEA(+)) were studied to examine the effect of sublethal hyperthermia in vitro on the cells' phenotype and sensitivity to CTL-mediated killing.The effect of RFA dose was investigated in vivo impacting (a) the phenotype and growth of MC38-CEA(+) tumors and (b) the induction of tumor-specific immune responses.Sequential administration of low-dose and high-dose RFA with vaccine decreased tumor recurrence compared to RFA alone.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.

ABSTRACT

Purpose: Radiofrequency ablation (RFA) is a minimally invasive energy delivery technique increasingly used for focal therapy to eradicate localized disease. RFA-induced tumor-cell necrosis generates an immunogenic source of tumor antigens known to induce antitumor immune responses. However, RFA-induced antitumor immunity is insufficient to control metastatic progression. We sought to characterize (a) the role of RFA dose on immunogenic modulation of tumor and generation of immune responses and (b) the potential synergy between vaccine immunotherapy and RFA aimed at local tumor control and decreased systemic progression.

Experimental design: Murine colon carcinoma cells expressing the tumor-associated (TAA) carcinoembryonic antigen (CEA) (MC38-CEA(+)) were studied to examine the effect of sublethal hyperthermia in vitro on the cells' phenotype and sensitivity to CTL-mediated killing. The effect of RFA dose was investigated in vivo impacting (a) the phenotype and growth of MC38-CEA(+) tumors and (b) the induction of tumor-specific immune responses. Finally, the molecular signature was evaluated as well as the potential synergy between RFA and poxviral vaccines expressing CEA and a TRIad of COstimulatory Molecules (CEA/TRICOM).

Results: In vitro, sublethal hyperthermia of MC38-CEA(+) cells (a) increased cell-surface expression of CEA, Fas, and MHC class I molecules and (b) rendered tumor cells more susceptible to CTL-mediated lysis. In vivo, RFA induced (a) immunogenic modulation on the surface of tumor cells and (b) increased T-cell responses to CEA and additional TAAs. Combination therapy with RFA and vaccine in CEA-transgenic mice induced a synergistic increase in CD4(+) T-cell immune responses to CEA and eradicated both primary CEA(+) and distal CEA(-) s.c. tumors. Sequential administration of low-dose and high-dose RFA with vaccine decreased tumor recurrence compared to RFA alone. These studies suggest a potential clinical benefit in combining RFA with vaccine in cancer patients, and augment support for this novel translational paradigm.

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Tumor phenotype and CEA-specific immune responses after ultra low-dose RFA.Female C57BL/6 mice (n = 7/group) were injected s.c. on day 0 with MC38-CEA+ tumor cells. On day 15, tumors were exposed to RFA sham (0 s) or ultra low-dose RFA (7 s, 60–70°C). A, on day 17, the cell-surface phenotype of pooled excised tumor cells was analyzed by flow cytometry. Histograms depict fluorescence intensity of CEA+ tumor cells expressing Fas, ICAM-1, and MHC class I H-2Kb and H-2Db before (dark histograms) and after (light histograms) RFA. Inset numbers represent % positive cells and MFI (parentheses) for each marker. B, on day 29, purified CD4+ splenic T cells from animals exposed to sham or low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein (0–50 ug/mL). Results are depicted as mean CEA-specific CD4+ proliferation ± S.E.M. after subtraction of background CD4+ reactivity to control beta-galactosidase protein. Asterisks denote statistical significance between treatment groups (P<0.05, 2-tailed t test). Effect of RFA on tumor phenotype data was performed twice yielding similar results.
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pone-0070417-g003: Tumor phenotype and CEA-specific immune responses after ultra low-dose RFA.Female C57BL/6 mice (n = 7/group) were injected s.c. on day 0 with MC38-CEA+ tumor cells. On day 15, tumors were exposed to RFA sham (0 s) or ultra low-dose RFA (7 s, 60–70°C). A, on day 17, the cell-surface phenotype of pooled excised tumor cells was analyzed by flow cytometry. Histograms depict fluorescence intensity of CEA+ tumor cells expressing Fas, ICAM-1, and MHC class I H-2Kb and H-2Db before (dark histograms) and after (light histograms) RFA. Inset numbers represent % positive cells and MFI (parentheses) for each marker. B, on day 29, purified CD4+ splenic T cells from animals exposed to sham or low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein (0–50 ug/mL). Results are depicted as mean CEA-specific CD4+ proliferation ± S.E.M. after subtraction of background CD4+ reactivity to control beta-galactosidase protein. Asterisks denote statistical significance between treatment groups (P<0.05, 2-tailed t test). Effect of RFA on tumor phenotype data was performed twice yielding similar results.

Mentions: Next, we examined whether the phenotypic changes induced in vitro by exposure to sublethal hyperthermia could be captured by the gradient of thermal energy arising from treatment of MC38-CEA+ tumors with ultra-low dose RFA in vivo. On day 0, female C57BL/6 mice were transplanted with MC38-CEA+ tumor cells, and on day 15 tumors received sham or ultra low-dose RFA (7 s, 60–70°C). On day 17, the phenotype of pooled excised CEA+ tumor cells was analyzed by flow cytometry for cell-surface expression of Fas, ICAM-1, H-2Kb, and H-2Db. As shown in Fig. 3A, ultra low-dose RFA exposure induced significant up-regulation of Fas, ICAM-1, and both MHC class I molecules in MC38-CEA+ tumors. Next we sought to examine if tumor exposure to ultra low-dose RFA could induce an anti-tumor immune response. On day 29, purified CD4+ splenic T cells from animals exposed to sham or ultra low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein. As shown in Fig. 3B, control animals exposed to RFA sham had minimal CD4+-specific proliferation to CEA. However, tumor exposure to ultra low-dose RFA induced a significant increase in CD4+ T-cell response relative to controls. Taken together, these data suggest that exposure to ultra low-dose RFA modulates tumors toward a more immunogenic phenotype and induces significant CEA-specific antitumor responses. Thus, it is feasible that clinical treatment of tumor lesions with RFA results in similar modulation at the thermal margin of the tumor [11].


Combination therapy with local radiofrequency ablation and systemic vaccine enhances antitumor immunity and mediates local and distal tumor regression.

Gameiro SR, Higgins JP, Dreher MR, Woods DL, Reddy G, Wood BJ, Guha C, Hodge JW - PLoS ONE (2013)

Tumor phenotype and CEA-specific immune responses after ultra low-dose RFA.Female C57BL/6 mice (n = 7/group) were injected s.c. on day 0 with MC38-CEA+ tumor cells. On day 15, tumors were exposed to RFA sham (0 s) or ultra low-dose RFA (7 s, 60–70°C). A, on day 17, the cell-surface phenotype of pooled excised tumor cells was analyzed by flow cytometry. Histograms depict fluorescence intensity of CEA+ tumor cells expressing Fas, ICAM-1, and MHC class I H-2Kb and H-2Db before (dark histograms) and after (light histograms) RFA. Inset numbers represent % positive cells and MFI (parentheses) for each marker. B, on day 29, purified CD4+ splenic T cells from animals exposed to sham or low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein (0–50 ug/mL). Results are depicted as mean CEA-specific CD4+ proliferation ± S.E.M. after subtraction of background CD4+ reactivity to control beta-galactosidase protein. Asterisks denote statistical significance between treatment groups (P<0.05, 2-tailed t test). Effect of RFA on tumor phenotype data was performed twice yielding similar results.
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Related In: Results  -  Collection

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pone-0070417-g003: Tumor phenotype and CEA-specific immune responses after ultra low-dose RFA.Female C57BL/6 mice (n = 7/group) were injected s.c. on day 0 with MC38-CEA+ tumor cells. On day 15, tumors were exposed to RFA sham (0 s) or ultra low-dose RFA (7 s, 60–70°C). A, on day 17, the cell-surface phenotype of pooled excised tumor cells was analyzed by flow cytometry. Histograms depict fluorescence intensity of CEA+ tumor cells expressing Fas, ICAM-1, and MHC class I H-2Kb and H-2Db before (dark histograms) and after (light histograms) RFA. Inset numbers represent % positive cells and MFI (parentheses) for each marker. B, on day 29, purified CD4+ splenic T cells from animals exposed to sham or low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein (0–50 ug/mL). Results are depicted as mean CEA-specific CD4+ proliferation ± S.E.M. after subtraction of background CD4+ reactivity to control beta-galactosidase protein. Asterisks denote statistical significance between treatment groups (P<0.05, 2-tailed t test). Effect of RFA on tumor phenotype data was performed twice yielding similar results.
Mentions: Next, we examined whether the phenotypic changes induced in vitro by exposure to sublethal hyperthermia could be captured by the gradient of thermal energy arising from treatment of MC38-CEA+ tumors with ultra-low dose RFA in vivo. On day 0, female C57BL/6 mice were transplanted with MC38-CEA+ tumor cells, and on day 15 tumors received sham or ultra low-dose RFA (7 s, 60–70°C). On day 17, the phenotype of pooled excised CEA+ tumor cells was analyzed by flow cytometry for cell-surface expression of Fas, ICAM-1, H-2Kb, and H-2Db. As shown in Fig. 3A, ultra low-dose RFA exposure induced significant up-regulation of Fas, ICAM-1, and both MHC class I molecules in MC38-CEA+ tumors. Next we sought to examine if tumor exposure to ultra low-dose RFA could induce an anti-tumor immune response. On day 29, purified CD4+ splenic T cells from animals exposed to sham or ultra low-dose RFA were tested by in vitro lymphoproliferation assay for reactivity to CEA protein. As shown in Fig. 3B, control animals exposed to RFA sham had minimal CD4+-specific proliferation to CEA. However, tumor exposure to ultra low-dose RFA induced a significant increase in CD4+ T-cell response relative to controls. Taken together, these data suggest that exposure to ultra low-dose RFA modulates tumors toward a more immunogenic phenotype and induces significant CEA-specific antitumor responses. Thus, it is feasible that clinical treatment of tumor lesions with RFA results in similar modulation at the thermal margin of the tumor [11].

Bottom Line: Murine colon carcinoma cells expressing the tumor-associated (TAA) carcinoembryonic antigen (CEA) (MC38-CEA(+)) were studied to examine the effect of sublethal hyperthermia in vitro on the cells' phenotype and sensitivity to CTL-mediated killing.The effect of RFA dose was investigated in vivo impacting (a) the phenotype and growth of MC38-CEA(+) tumors and (b) the induction of tumor-specific immune responses.Sequential administration of low-dose and high-dose RFA with vaccine decreased tumor recurrence compared to RFA alone.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Tumor Immunology and Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.

ABSTRACT

Purpose: Radiofrequency ablation (RFA) is a minimally invasive energy delivery technique increasingly used for focal therapy to eradicate localized disease. RFA-induced tumor-cell necrosis generates an immunogenic source of tumor antigens known to induce antitumor immune responses. However, RFA-induced antitumor immunity is insufficient to control metastatic progression. We sought to characterize (a) the role of RFA dose on immunogenic modulation of tumor and generation of immune responses and (b) the potential synergy between vaccine immunotherapy and RFA aimed at local tumor control and decreased systemic progression.

Experimental design: Murine colon carcinoma cells expressing the tumor-associated (TAA) carcinoembryonic antigen (CEA) (MC38-CEA(+)) were studied to examine the effect of sublethal hyperthermia in vitro on the cells' phenotype and sensitivity to CTL-mediated killing. The effect of RFA dose was investigated in vivo impacting (a) the phenotype and growth of MC38-CEA(+) tumors and (b) the induction of tumor-specific immune responses. Finally, the molecular signature was evaluated as well as the potential synergy between RFA and poxviral vaccines expressing CEA and a TRIad of COstimulatory Molecules (CEA/TRICOM).

Results: In vitro, sublethal hyperthermia of MC38-CEA(+) cells (a) increased cell-surface expression of CEA, Fas, and MHC class I molecules and (b) rendered tumor cells more susceptible to CTL-mediated lysis. In vivo, RFA induced (a) immunogenic modulation on the surface of tumor cells and (b) increased T-cell responses to CEA and additional TAAs. Combination therapy with RFA and vaccine in CEA-transgenic mice induced a synergistic increase in CD4(+) T-cell immune responses to CEA and eradicated both primary CEA(+) and distal CEA(-) s.c. tumors. Sequential administration of low-dose and high-dose RFA with vaccine decreased tumor recurrence compared to RFA alone. These studies suggest a potential clinical benefit in combining RFA with vaccine in cancer patients, and augment support for this novel translational paradigm.

Show MeSH
Related in: MedlinePlus