No 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.

For the first time, the intense killing activity of CIK cells against autologous metastatic melanoma, including mCSCs, has been shown. These findings move clinical investigation of a new immunotherapy for metastatic melanoma, including mCSCs, closer.

This work reports the effective antitumor activity of patient-derived cytokine-induced killer (CIK) cells against autologous chemo-resistant melanoma Cancer Stem Cells (CSCs).CSCs are clinical relevant targets, associated with disease relapse. We demonstrate that chemotherapy kills indeed proliferating melanoma cells but spares tumorigenic CSCs, in vitro and in vivo. The MHCindependent immunotherapy with CIK cells was proved successful in this challenging framework.Consistent findings were obtained in selected cases of BRAF mutated melanoma treated with small molecule BRAFi. Our data, generated within an autologous system, support the exploration of CIK cells in clinical trials. Cost effectiveness, safety profile and ability to overcome tumor MHC-downregulation are favorable issues to be considered in clinical perspective. CIK cells may be integrated at different levels in the composite therapeutic scenario of metastatic melanoma, offering an additional weapon to control tumor spread and promote its eradication. ABSTRACT PurposeThe MHC-unrestricted activity of cytokine-induced killer (CIK) cells against chemo-surviving melanoma cancer stem cells (mCSCs) was explored, as CSCs are considered responsible for chemo-resistance and relapses. Experimental designPutative mCSCs were visualized by engineering patient-derived melanoma cells (MCs) with a lentiviralvector encoding eGFP under expression control by stemness gene promoter oct4. Their stemness potential was confirmed in vivo by limiting dilution assays.We explored the sensitivity of eGFP CIK cell activity against chemoresistant mCSCs was confirmed vivo in two distinct immunodeficient murine models. ResultsWe visualized eGFP + mCSCs (14±2.1%) in 11 MCs. The tumorigenic precursor rate in vivo was higher within eGFP-positive MCs (1/42) compared with the eGFP-negative counterpart (1/4870).In vitro mCSCs were relatively resistant to CHT and BRAFi, but killed by CIK cells ( ConclusionsThese findings are the first demonstration that immunotherapy with CIK cells is active against autologous mCSCs surviving chemotherapy or BRAFi. An experimental platform for mCSC study and rationale for CIK cells in melanoma clinical study is provided.

Allogeneic hematopoietic cell transplant (HCT) remains the only curative therapy for many hematologic malignancies but it is limited by high nonrelapse mortality (NRM), primarily from unpredictable control of graft-versus-host disease (GVHD). Recently, post-transplant cyclophosphamide demonstrated improved GVHD control in allogeneic bone marrow HCT. Here we explore cyclophosphamide in allogeneic peripheral blood stem cell transplantation (alloPBSCT). Patients with high-risk hematologic malignancies received alloPBSCT from HLA-matched unrelated/related donors. GVHD prophylaxis included combination post-HCT cyclophosphamide 50 mg/kg (days +3 and +4) and tacrolimus/mofetil mycophenolate (T/MMF) (day +5 forward). The primary objective was the cumulative incidence of acute and chronic GVHD. Between March 2011 and May 2015, 35 consecutive patients received the proposed regimen. MMF was stopped in all patients at day +28; the median discontinuation of tacrolimus was day +113. Acute and chronic GVHD cumulative incidences were 17% and 7%, respectively, with no grade IV GVHD events, only 2 patients requiring chronic GVHD immunosuppression control, and no deaths from GVHD. Two-year NRM, overall survival, event-free survival, and chronic GVHD event-free survival rates were 3%, 77%, 54%, and 49%, respectively. The graft-versus-tumor effect was maintained as 5 of 15 patients (33%) who received HCT with evidence of disease experienced further disease response. A post-transplant cyclophosphamide + T/MMF combination strategy effectively prevented acute and chronic GVHD after alloPBSCT from HLA-matched donors and achieved an unprecedented low NRM without losing efficacy in disease control or impaired development of the graft-versus-tumor effect. This trial is registered at clinicaltrials.gov as NCT02300571.