[Adoptive T-cell therapy of rhabdomyosarcoma].
OBJECTIVE
To improve survival of patients with advanced rhabdomyosarcomas (RMS), we aimed to adoptively transfer T-cells with redirected specificity for the fetal acetylcholine receptor (AChR), an RMS-specific cell surface antigen.


METHODS
A "second generation" chimeric antigen receptor (CAR) with a combined CD28-CD3ζ signaling domain was derived from our previously described chimeric antigen receptor composed of an extracellular human anti-fAChR antibody fragment, an Fc hinge region, and the intracellular T-cell receptor zeta chain. Lymphocytes from the peripheral blood were modified by retroviral transduction and monitored by FACS analysis. Cytotoxicity of modified T-cells towards RMS cells was recorded by MTT-based viability tests; expression of co-stimulatory molecules and anti-apoptotic genes was studied by FACS and qRT-PCR analysis.


RESULTS
Co-stimulatory molecules were expressed in low levels on RMS cells giving the rationale to generate a CD28-CD3ζ signalling CAR (chimeric antigen receptor) for redirecting T-cells. T-cells were successfully engineered with the "second generation" AChR-specific chimeric antigen receptor. Despite of high CAR expression engineered T-cells showed low killing efficiency towards RMS compared to redirected killing of CD20+ lymphoma or CEA-expressing adenocarcinoma cell lines when redirected by CD20- and/or CEA-specific CAR.


CONCLUSIONS
Data suggest that RMS cells exhibit resistance to a T-cell attack redirected by a fAChR-specific CAR. Inhibition of anti-apoptotic pathways in those cells may improve sensitivity to conventional as well as T-cell-based therapeutics.
Simon-Keller
K
K
Pathologisches Institut, Universitätsmedizin Mannheim, Universität Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim. Katja.simon-keller@medma.uni-heidelberg.de
Paschen
A
A
Eichmüller
S
S
Gattenlöhner
S
S
Barth
S
S
Koscielniak
E
E
Leuschner
I
I
Stöbel
P
P
Hombach
A
A
Abken
H
H
Marx
A
A
D045744:Cell Line, Tumor; D046528:Chimerism; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000276:immunology; D007128:Immunoglobulin Fragments / Q000276:immunology; D016219:Immunotherapy, Adoptive / Q000379:methods*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011950:Receptors, Cholinergic / Q000276:immunology; D012208:Rhabdomyosarcoma / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D013601:T-Lymphocytes / Q000276:immunology*
D007141:Immunoglobulin Fc Fragments; D007128:Immunoglobulin Fragments; D011948:Receptors, Antigen, T-Cell; D011950:Receptors, Cholinergic; C054979:antigen T cell receptor, zeta chain