Cytokine-Induced Killer Cells Eradicate Bone and Soft-Tissue Sarcomas

Abstract

Unresectable metastatic bone sarcoma and soft-tissue sarcomas (STS) are incurable due to the inability to eradicate chemoresistant cancer stem-like cells (sCSC) that are likely responsible for relapses and drug resistance. In this study, we investigated the preclinical activity of patient-derived cytokine-induced killer (CIK) cells against autologous bone sarcoma and STS, including against putative sCSCs. Tumor killing was evaluated both in vitro and within an immunodeficient mouse model of autologous sarcoma. To identify putative sCSCs, autologous bone sarcoma and STS cells were engineered with a CSC detector vector encoding eGFP under the control of the human promoter for OCT4, a stem cell gene activated in putative sCSCs. Using CIK cells expanded from 21 patients, we found that CIK cells efficiently killed allogeneic and autologous sarcoma cells in vitro. Intravenous infusion of CIK cells delayed autologous tumor growth in immunodeficient mice. Further in vivo analyses established that CIK cells could infiltrate tumors and that tumor growth inhibition occurred without an enrichment of sCSCs relative to control-treated animals. These results provide preclinical proof-of-concept for an effective strategy to attack autologous sarcomas, including putative sCSCs, supporting the clinical development of CIK cells as a novel class of immunotherapy for use in settings of untreatable metastatic disease. Cancer Res; 74(1); 119-29. Ó2013 AACR.

Cytokine Induced Killer cells are effective against sarcoma cancer stem cells spared by chemotherapy and target therapy.

“…30 Here, we advanced to the next experimental level, closer to a pragmatic clinical scenario. We demonstrated that sCSC are relatively resistant to chemotherapy and target therapies but susceptible to MHC-independent immunotherapy with autologous CIK cells.…”

“…This was previously described and validated by our group. 30,31,46 We provide a new functional angle of analysis, exploring the sensitivity of putative sCSC to conventional chemotherapy. We acknowledge that the proposed methodology to visualize sCSC has objective limitations and cannot guarantee to capture all the “true” sCSC.…”

“…30 S22 osteosarcoma culture was generated starting from freshly isolated thoracentesis, obtained in a sterile vacuum bottle. Tumoral cells were isolated from fluid by centrifugation and resuspended in KnockOut Dulbecco’s Modified Eagle’s: Nutrient Mixture F-12 Medium (KO DMEM:F12 medium, Gibco BRL, Life Technologies Italia) with the addition of penicillin (50 U/ml), streptomycin (50 μg/ml), Glutamax 100X (all from Gibco BRL, Life Technologies Italia).…”

“…eGFP.Wpre (LV-Oct4.eGFP) was obtained by replacing the expression cassette hPGK.eGFP into LV-PGK.eGFP with the hOct4-eGFP, cleaved from phOct4-eGFP vector, by insertion into SalI and XhoI restriction enzyme sites. 30,31 Physical titers for lentiviral vector stocks were determined on the basis of p24 antigen content (HIV-1 p24 ELISA kit; PerkinElmer).…”

“…30 We also provided proof of concept that sCSC could be killed in vitro by a MHC-independent immunotherapy approach based on Cytokine-Induced Killer cells (CIK). 30,31 We now asked whether sCSC were resistant to chemo and targeted therapies currently used in clinical practice, exploring if a sequential immunotherapy with CIK might be effective against chemo- and target- therapy resistant sCSC.…”