Genomic stability and functional activity may be lost in telomerase-transduced human CD8+ T lymphocytes

Abstract

To obtain the large amount of T cells required for adoptive immunotherapy in a clinical setting, T-cell lifespan extension by human telomerase reverse transcriptase (hTERT) transduction is of particular interest. However, constitutive expression of hTERT is associated with malignant transformation and thus warrants a detailed evaluation of the safety of hTERTtransduced T cells before clinical application. In view of this, we performed an extensive cytogenetic analysis of hTERTtransduced MART-1 (melanoma antigen recognized by T cell 1)-and human papillomavirus type 16 (HPV16) E7-specific human CD8 ؉ cytotoxic T lymphocytes (CTLs), reactive against melanoma and cervical carcinoma, respectively. Our results, obtained by (spectral) karyotyping and array comparative genomic hybridization, showed the development of minor chromosomal aberrations in an hTERTtransduced MART-1-specific CTL clone, whereas severe clonal aberrations were detected in an hTERT-transduced HPV16 E7-specific CTL clone. Furthermore, hTERT transduction did not protect CTLs from immunosenescence, because the HPV16 E7-specific, hTERT-transduced CTL clone showed a decreased functional activity on prolonged culture. Although the general frequency of major chromosomal aberrations in hTERTtransduced CTLs and the in vivo significance of our observations remain still unclear at this point, the currently available data suggest that clinical application of hTERT-transduced CTLs should pro- IntroductionAdoptive immunotherapy using tumor-reactive T lymphocytes represents an alternative strategy to treat malignant disease. In different animal models, adoptive transfer of specific cytotoxic T lymphocytes (CTLs) has resulted in the eradication of established tumors. [1][2][3][4] Also in patients with melanoma, adoptive CTL therapy has resulted in objective tumor regressions 5,6 and thus holds promise as a treatment modality against malignant disease in a clinical setting. 7 Given the poor immunogenicity of most tumor cells, the in vitro selection prior to adoptive transfer of high-avidity tumor reactive CTL clones could further improve the efficacy of in vivo tumor rejection. 8,9 However, the expansion for therapeutic purposes of CTL clones with considerable in vitro replicative history can be severely hampered by replicative senescence. 10,11 It has become clear that the catalytic subunit of the human telomerase complex, human telomerase reverse transcriptase (hTERT), can efficiently reverse replicative senescence (reviewed in Ducrest et al 12 ). The ability of hTERT to elongate and stabilize telomeric ends can be exploited to restore the replicative potential of presenescent cells. Ectopic expression of hTERT has successfully mediated the in vitro lifespan extension of various human cell types, including fibroblasts, endothelial cells, muscle cells, and neuronal cells. [13][14][15][16] Additionally, hTERT transduction of human T lymphocytes has resulted in restoration of their replicative potential in vitro. This has allowed the successful lifespan extension o...

Aging and Immune Function: Molecular Mechanisms to Interventions

“…However, some studies have demonstrated chromosomal abnormalities in these hTERT-transduced T cells (332). Additionally, long-term hTERT-transduced T cells show accumulation of cyclin-dependent kinase inhibitors such as p21 and p16ink4a.…”

Cross-platform array comparative genomic hybridization meta-analysis separates hematopoietic and mesenchymal from epithelial tumors

“…These include either BAC arrays from the Sanger Institute in Cambridge (UK), the University of California in San Francisco (UCSF, San Francisco, USA) and our Amsterdam laboratories (VUMC, The Netherlands); oligonucleotide CGH arrays from our laboratory in Amsterdam; and cDNA arrays from Stanford University ( Table 1). The new VUMC BAC array CGH and oligoarray CGH experiments were performed according to protocols previously described (Schreurs et al, 2005;van den IJssel et al, 2005) and data are available at Gene Expression Omnibus (GEO) http://www.ncbi.nlm.nih.gov/geo/ (Edgar et al, 2002), under Accession number GSE5051. The fallopian data set is available at http://cc.ucsf.edu/albertson/public/, all others are as stated in the references (Table 1).…”

Principles of adoptive T cell cancer therapy

“…TERT reprogrammed T cells mount effective immune responses following adoptive transfer into mice bearing tumor xenografts (118). However, although in vitro studies so far indicate that constitutive TERT expression achieves immortalization without malignant transformation, caution is urged with the clinical use of life span-extended human T cells because chromosomal instability, which is associated with tumor development, has been observed in human T cells constitutively expressing TERT (119,120).…”