Antitumor efficacy of 90Y-NM600 targeted radionuclide therapy and PD-1 blockade is limited by regulatory T cells in murine prostate tumors

© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ..

BACKGROUND: Systemic radiation treatments that preferentially irradiate cancer cells over normal tissue, known as targeted radionuclide therapy (TRT), have shown significant potential for treating metastatic prostate cancer. Preclinical studies have demonstrated the ability of external beam radiation therapy (EBRT) to sensitize tumors to T cell checkpoint blockade. Combining TRT approaches with immunotherapy may be more feasible than combining with EBRT to treat widely metastatic disease, however the effects of TRT on the prostate tumor microenvironment alone and in combinfation with checkpoint blockade have not yet been studied.

METHODS: C57BL/6 mice-bearing TRAMP-C1 tumors and FVB/NJ mice-bearing Myc-CaP tumors were treated with a single intravenous administration of either low-dose or high-dose 90Y-NM600 TRT, and with or without anti-PD-1 therapy. Groups of mice were followed for tumor growth while others were used for tissue collection and immunophenotyping of the tumors via flow cytometry.

RESULTS: 90Y-NM600 TRT was safe at doses that elicited a moderate antitumor response. TRT had multiple effects on the tumor microenvironment including increasing CD8 +T cell infiltration, increasing checkpoint molecule expression on CD8 +T cells, and increasing PD-L1 expression on myeloid cells. However, PD-1 blockade with TRT treatment did not improve antitumor efficacy. Tregs remained functional up to 1 week following TRT, but CD8 +T cells were not, and the suppressive function of Tregs increased when anti-PD-1 was present in in vitro studies. The combination of anti-PD-1 and TRT was only effective in vivo when Tregs were depleted.

CONCLUSIONS: Our data suggest that the combination of 90Y-NM600 TRT and PD-1 blockade therapy is ineffective in these prostate cancer models due to the activating effect of anti-PD-1 on Tregs. This finding underscores the importance of thorough understanding of the effects of TRT and immunotherapy combinations on the tumor immune microenvironment prior to clinical investigation.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:10

Enthalten in:

Journal for immunotherapy of cancer - 10(2022), 8 vom: 24. Aug.

Sprache:

Englisch

Beteiligte Personen:

Potluri, Hemanth K [VerfasserIn]
Ferreira, Carolina A [VerfasserIn]
Grudzinski, Joseph [VerfasserIn]
Massey, Christopher [VerfasserIn]
Aluicio-Sarduy, Eduardo [VerfasserIn]
Engle, Jonathan W [VerfasserIn]
Kwon, Ohyun [VerfasserIn]
Marsh, Ian R [VerfasserIn]
Bednarz, Bryan P [VerfasserIn]
Hernandez, Reinier [VerfasserIn]
Weichert, Jamey P [VerfasserIn]
McNeel, Douglas G [VerfasserIn]

Links:

Volltext

Themen:

CD8-Positive T-Lymphocytes
CTLA-4 Antigen
Journal Article
Prostatic Neoplasms
Radioimmunotherapy
Radioisotopes
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

Anmerkungen:

Date Completed 26.08.2022

Date Revised 14.09.2022

published: Print

Citation Status MEDLINE

doi:

10.1136/jitc-2022-005060

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM345206479