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An Optimized GD2-Targeting Retroviral Cassette for More Potent and Safer Cellular Therapy of Neuroblastoma and Other Cancers.

Thomas S, Straathof K, Himoudi N, Anderson J, Pule M - PLoS ONE (2016)

Bottom Line: GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues.Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell.Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.

View Article: PubMed Central - PubMed

Affiliation: Cancer Institute, University College London, London, United Kingdom.

ABSTRACT
Neuroblastoma is the commonest extra cranial solid cancer of childhood. Despite escalation of treatment regimens, a significant minority of patients die of their disease. Disialoganglioside (GD2) is consistently expressed at high-levels in neuroblastoma tumors, which have been targeted with some success using therapeutic monoclonal antibodies. GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues. Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell. Clinical data with early CAR designs directed against GD2 have shown some promise in Neuroblastoma. Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.

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Related in: MedlinePlus

In vivo testing of GD2 CAR.Balb-C mice were innocultaed with 1x106 CT26 or CT26-GD2 cell mixed in matrigel. 10 days post tumour inoculation, mice were sub-lethally irradiated (200 rads) and two weeks post tumour injection, mice were intravenously transplanted with a total of 1.5x106 transduced splenocytes or non transduced controls by tail vein injection. Wild type CT26 were used as antigen negative controls (a,c) whereas CT26 –GD2 tumors treated with untransduced T cells (b) did not regress whilst CT26-GD2 tumors challenged with CAR T cells regressed. Each line represents one mouse.
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pone.0152196.g006: In vivo testing of GD2 CAR.Balb-C mice were innocultaed with 1x106 CT26 or CT26-GD2 cell mixed in matrigel. 10 days post tumour inoculation, mice were sub-lethally irradiated (200 rads) and two weeks post tumour injection, mice were intravenously transplanted with a total of 1.5x106 transduced splenocytes or non transduced controls by tail vein injection. Wild type CT26 were used as antigen negative controls (a,c) whereas CT26 –GD2 tumors treated with untransduced T cells (b) did not regress whilst CT26-GD2 tumors challenged with CAR T cells regressed. Each line represents one mouse.

Mentions: To confirm that the efficacy and specificity of the co-expressed optimized CAR and suicide gene observed in vitro was likely to equate to clinical efficacy we evaluated the iCasp9-CAR cassette in an immunocompetent mouse model. The GD2 antigen is a ganglioside of identical chemical structure between species so the ScFv huK666 ScFv binds GD2 equally in mouse and human cells. We made use of the weakly immunogenic CT26 colon cancer cell line, which consistently forms tumours subcutaneously in Balb/c mice. CT26 cells were transduced with a gammaretrovirus encoding GD2 and GD3 synthases, and a clone (number 7) with bright GD2 expression was selected for analysis of GD2 targeting by the GD2-CAR in an immunocompetent model (S1 Fig). CT26-clone 7 cells induced specific release of IL-2 and IFN-γ following co-culture with splenocytes transduced with GD2-CAR (S2 Fig). In vivo, CT26-GD2 clone 7-derived tumors were efficiently eliminated by CAR transduced splenocytes in contrast to GD2 negative CT26 cells which grew at the same rate as tumors in mice treated with untransduced splenocytes (Fig 6).


An Optimized GD2-Targeting Retroviral Cassette for More Potent and Safer Cellular Therapy of Neuroblastoma and Other Cancers.

Thomas S, Straathof K, Himoudi N, Anderson J, Pule M - PLoS ONE (2016)

In vivo testing of GD2 CAR.Balb-C mice were innocultaed with 1x106 CT26 or CT26-GD2 cell mixed in matrigel. 10 days post tumour inoculation, mice were sub-lethally irradiated (200 rads) and two weeks post tumour injection, mice were intravenously transplanted with a total of 1.5x106 transduced splenocytes or non transduced controls by tail vein injection. Wild type CT26 were used as antigen negative controls (a,c) whereas CT26 –GD2 tumors treated with untransduced T cells (b) did not regress whilst CT26-GD2 tumors challenged with CAR T cells regressed. Each line represents one mouse.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4816271&req=5

pone.0152196.g006: In vivo testing of GD2 CAR.Balb-C mice were innocultaed with 1x106 CT26 or CT26-GD2 cell mixed in matrigel. 10 days post tumour inoculation, mice were sub-lethally irradiated (200 rads) and two weeks post tumour injection, mice were intravenously transplanted with a total of 1.5x106 transduced splenocytes or non transduced controls by tail vein injection. Wild type CT26 were used as antigen negative controls (a,c) whereas CT26 –GD2 tumors treated with untransduced T cells (b) did not regress whilst CT26-GD2 tumors challenged with CAR T cells regressed. Each line represents one mouse.
Mentions: To confirm that the efficacy and specificity of the co-expressed optimized CAR and suicide gene observed in vitro was likely to equate to clinical efficacy we evaluated the iCasp9-CAR cassette in an immunocompetent mouse model. The GD2 antigen is a ganglioside of identical chemical structure between species so the ScFv huK666 ScFv binds GD2 equally in mouse and human cells. We made use of the weakly immunogenic CT26 colon cancer cell line, which consistently forms tumours subcutaneously in Balb/c mice. CT26 cells were transduced with a gammaretrovirus encoding GD2 and GD3 synthases, and a clone (number 7) with bright GD2 expression was selected for analysis of GD2 targeting by the GD2-CAR in an immunocompetent model (S1 Fig). CT26-clone 7 cells induced specific release of IL-2 and IFN-γ following co-culture with splenocytes transduced with GD2-CAR (S2 Fig). In vivo, CT26-GD2 clone 7-derived tumors were efficiently eliminated by CAR transduced splenocytes in contrast to GD2 negative CT26 cells which grew at the same rate as tumors in mice treated with untransduced splenocytes (Fig 6).

Bottom Line: GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues.Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell.Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.

View Article: PubMed Central - PubMed

Affiliation: Cancer Institute, University College London, London, United Kingdom.

ABSTRACT
Neuroblastoma is the commonest extra cranial solid cancer of childhood. Despite escalation of treatment regimens, a significant minority of patients die of their disease. Disialoganglioside (GD2) is consistently expressed at high-levels in neuroblastoma tumors, which have been targeted with some success using therapeutic monoclonal antibodies. GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues. Chimeric Antigen Receptors (CARs) are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell. Clinical data with early CAR designs directed against GD2 have shown some promise in Neuroblastoma. Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.

Show MeSH
Related in: MedlinePlus