Cytokine-induced killer cells kill chemo-surviving melanoma cancer stem cells

Loretta Gammaitoni, Lidia Giraudo, Marco MacAgno, Valeria Leuci, Giulia Mesiano, Ramona Rotolo, Francesco Sassi, Martina Sanlorenzo, Alessandro Zaccagna, Alberto Pisacane, Rebecca Senetta, Michela Cangemi, Giulia Cattaneo, Valentina Martin, Valentina Coha, Susanna Gallo, Ymera Pignochino, Anna Sapino, Giovanni Grignani, Fabrizio Carnevale-SchiancaMassimo Aglietta, Dario Sangiolo

Research output: Contribution to journalArticlepeer-review


Purpose: The MHC-unrestricted activity of cytokine-induced killer (CIK) cells against chemo-surviving melanoma cancer stem cells (mCSC) was explored, as CSCs are considered responsible for chemoresistance and relapses. Experimental Design: Putative mCSCs were visualized by engineering patient-derived melanoma cells (MC) with a lentiviral vector 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+ mCSCs to chemotherapy (CHT), BRAF inhibitor (BRAFi) or CIK cells, as single agents or in sequence, in vitro. First, we treated MCs in vitro with fotemustine or dabrafenib (BRAF mutated cases); then, surviving MCs, enriched in mCSCs, were challenged with autologous CIK cells. CIK cell activity against chemoresistant mCSCs was confirmed in vivo in two distinct immunodeficient murine models. Results: Wevisualized eGFP+ mCSCs (14%±2.1%) in 11MCs. The tumorigenic precursor rate in vivo was higher within eGFP+ MCs (1/42) compared with the eGFP- counterpart (1/4,870). In vitro mCSCs were relatively resistant to CHT and BRAFi, but killed by CIK cells (n = 11, 8/11 autologous), with specific lysis ranging from 95% [effector:tumor ratio (E:T), 40:1] to 20% (E:T 1:3). In vivo infusion of autologous CIK cells into mice bearing xenografts from three distinct melanomas demonstrated significant tumor responses involving CHT-spared eGFP+ mCSCs (P=0.001). Sequential CHT-immunotherapy treatment retained antitumor activity (n = 12, P = 0.001) reducing mCSC rates (P = 0.01). Conclusions: These findings are the first demonstration that immunotherapy with CIK cells is active against autologous mCSCs surviving CHT or BRAFi. An experimental platform for mCSC study and rationale for CIK cells in melanoma clinical study is provided.

Original languageEnglish
Pages (from-to)2277-2288
Number of pages12
JournalClinical Cancer Research
Issue number9
Publication statusPublished - May 1 2017

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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