Combined mitoxantrone and anti-TGFβ treatment with PD-1 blockade enhances antitumor immunity by remodelling the tumor immune landscape in neuroblastoma.

Abstract

BACKGROUND:

Poor infiltration of functioning T cells renders tumors unresponsive to checkpoint-blocking immunotherapies. Here, we identified a combinatorial in situ immunomodulation strategy based on the administration of selected immunogenic drugs and immunotherapy to sensitize poorly T-cell-infiltrated neuroblastoma (NB) to the host antitumor immune response.

METHODS:

975A2 and 9464D NB cell lines derived from spontaneous tumors of TH-MYCN transgenic mice were employed to study drug combinations able of enhancing the antitumor immune response using in vivo and ex vivo approaches. Migration of immune cells towards drug-treated murine-derived organotypic tumor spheroids (MDOTS) were assessed by microfluidic devices. Activation status of immune cells co-cultured with drug-treated MDOTS was evaluated by flow cytometry analysis. The effect of drug treatment on the immune content of subcutaneous or orthotopic tumors was comprehensively analyzed by flow-cytometry, immunohistochemistry and multiplex immunofluorescence. The chemokine array assay was used to detect soluble factors released into the tumor microenvironment. Patient-derived organotypic tumor spheroids (PDOTS) were generated from human NB specimens. Migration and activation status of autologous immune cells to drug-treated PDOTS were performed.

RESULTS:

We found that treatment with low-doses of mitoxantrone (MTX) recalled immune cells and promoted CD8+ T and NK cell activation in MDOTS when combined with TGFβ and PD-1 blockade. This combined immunotherapy strategy curbed NB growth resulting in the enrichment of a variety of both lymphoid and myeloid immune cells, especially intratumoral dendritic cells (DC) and IFNγ- and granzyme B-expressing CD8+ T cells and NK cells. A concomitant production of inflammatory chemokines involved in remodelling the tumor immune landscape was also detected. Interestingly, this treatment induced immune cell recruitment against PDOTS and activation of CD8+ T cells and NK cells.

CONCLUSIONS:

Combined treatment with low-dose of MTX and anti-TGFβ treatment with PD-1 blockade improves antitumor immunity by remodelling the tumor immune landscape and overcoming the immunosuppressive microenvironment of aggressive NB.

• Authors: Valeria Lucarini, Ombretta Melaiu, Silvia D'Amico, Fabio Pastorino, Patrizia Tempora, Marco Scarsella, Marco Pezzullo, Adele De Ninno, Valentina D'Oria, Michele Cilli, Laura Emionite, Paola Infante, Lucia Di Marcotullio, Maria Antonietta De Ioris, Giovanni Barillari, Rita Alaggio, Luca Businaro, Mirco Ponzoni, Franco Locatelli, Doriana Fruci
• Journal: Journal of experimental & clinical cancer research : CR (J Exp Clin Cancer Res) Vol. 41 Issue 1 Pg. 326 (Nov 17 2022) ISSN: 1756-9966 [Electronic] England
• PMID: 36397148 (Publication Type: Journal Article)
• Copyright: © 2022. The Author(s).

Chemical References

• Programmed Cell Death 1 Receptor
• Mitoxantrone
• Transforming Growth Factor beta

Topics

• Humans
• Mice
• Animals
• Programmed Cell Death 1 Receptor
• Mitoxantrone (pharmacology)
• CD8-Positive T-Lymphocytes
• Transforming Growth Factor beta
• Cell Line, Tumor
• Neuroblastoma (drug therapy)
• Mice, Transgenic
• Tumor Microenvironment