Natural killer cell-based adoptive immunotherapy eradicates and drives differentiation of chemoresistant bladder cancer stem-like cells

Abstract

BackgroundHigh-grade non-muscle invasive bladder cancer (NMIBC) has a high risk of recurrence and progression to muscle-invasive forms, which seems to be largely related to the presence of tumorigenic stem-like cell populations that are refractory to conventional therapies. Here, we evaluated the therapeutic potential of Natural Killer (NK) cell-based adoptive immunotherapy against chemoresistant bladder cancer stem-like cells (CSCs) in a pre-clinical relevant model, using NK cells from healthy donors and NMIBC patients.MethodsCytokine-activated NK cells from healthy donors and from high-grade NMIBC patients were phenotypically characterized and assayed in vitro against stem-like and bulk differentiated bladder cancer cells. Stem-like cells were isolated from two bladder cancer cell lines using the sphere-forming assay. The in vivo therapeutic efficacy was evaluated in mice bearing a CSC-induced orthotopic bladder cancer. Animals were treated by intravesical instillation of interleukin-activated NK cells. Tumor response was evaluated longitudinally by non-invasive bioluminescence imaging.ResultsNK cells from healthy donors upon activation with IL-2 and IL-15 kills indiscriminately both stem-like and differentiated tumor cells via stress ligand recognition. In addition to cell killing, NK cells shifted CSCs towards a more differentiated phenotype, rendering them more susceptible to cisplatin, highlighting the benefits of a possible combined therapy. On the contrary, NK cells from NMIBC patients displayed a low density on NK cytotoxicity receptors, adhesion molecules and a more immature phenotype, losing their ability to kill and drive differentiation of CSCs. The local administration, via the transurethral route, of activated NK cells from healthy donors provides an efficient tumor infiltration and a subsequent robust tumoricidal activity against bladder cancer with high selective cytolytic activity against CSCs, leading to a dramatic reduction in tumor burden from 80 % to complete remission.ConclusionAlthough pre-clinical, our results strongly suggest that an immunotherapeutic strategy using allogeneic activated NK cells from healthy donors is effective and should be exploited as a complementary therapeutic strategy in high-risk NMIBC patients to prevent tumor recurrence and progression.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-016-0715-2) contains supplementary material, which is available to authorized users.

Umbilical cord blood CD34+progenitor-derived NK cells efficiently kill ovarian cancer spheroids and intraperitoneal tumors in NOD/SCID/IL2Rgnullmice

“… 37 In a bladder cancer mouse model, intravesical NK cell administration shows a significant higher infiltration rate than systemic delivery. 33 Furthermore, investigators at the University of Minnesota have clearly demonstrated in a mouse model with the OC cell line MA148 that the i.p. delivery route of activated NK cells is superior to i.v.…”

Inhibition of EZH2 induces NK cell-mediated differentiation and death in muscle-invasive bladder cancer

“…To evaluate whether transcript level changes in NK cell-associated signaling increased infiltrating lymphocytes in EPZ011989-treated xenografts, we used CD56 also known as Neural Cell Adhesion Molecule 1 (NCAM1) and NCR1 (Natural Cytotoxicity triggering Receptor 1) as markers of NK cells [36]. CD56 staining was significantly higher in combination-treated xenografts compared with vehicle, cisplatin and EPZ011989-treated mice (Fig.…”

New avenues for melanoma immunotherapy: Natural Killer cells?

“…For instance, radiotherapy, in addition to eliminating tumour bulk, has been shown to induce the upregulation of NK cell‐activating ligands on surviving CSCs, enhancing NK cells cytotoxicity and improving survival when NK cells are infused in the host . On the other hand, adoptive transfer of NK cells can eliminate the cancer stem cell compartment making the tumour more differentiated and sensitive to chemotherapeutic drugs …”