Bone marrow derived mesenchymal stem/stromal cells transduced with full length human TRAIL repress the growth of rhabdomyosarcoma cells in vitro

Rhabdomyosarcoma (RMS) is the most frequent juve nal cancer originating from skeletal muscle and patient survival is poor in case of metastatic disease. New target ed therapeutics are critically needed. In a recent Hematologica paper Kuci et al. 1 reported that in vitro cul tured cytokine-induced killer (CIK) cells effectively lysed the targeted rhabdomyosarcoma (RMS) cell lines and proposed that CIK cells may be used as a novel adoptive immunotherapy for the treatment of patients with RMS after allogeneic stem cell transplantation. The authors showed that TRAIL expression con tributes to the antitumor effect of CIK cells by inducing caspase activation in rhabdomyosarcoma cell lines. Furthermore, they provided evidence that not every RMS cell line is equally sensitive for TRAIL-mediated CIKinduced cytotoxicity. We have previously shown for the first time on a panel of RMS cell lines that around half of them were highly sensitive for the hr-TRAIL-induced caspase-mediated apoptosis. 2 RMS cell line type did not determine their response to TRAIL as several alveolar RMS cell lines were sensitive to TRAIL while an embrional RMS cell line was resistant. 2 Further research revealed that resistance of RMS cells to TRAIL can be the result of dysregulation of various molecular components such as FLIP overexpres sion, 2 casein kinase II (CK2) overactivity 3 or Bcl-2 overex pression. 3,4