Abstract 1581: Prostate tumor associated NK cells (PTANKs) acquire the decidual-like/pro-angiogenic phenotype and polarize macrophages towards the M2-like/TAM subset
Authors: Bruno Antonino , Baci Denisa , Gallazzi Matteo , Bosi Annalisa , Naselli Angelo , Guarneri Andrea , Mortara Lorenzo , Noonan Douglas , Albini Adriana 
Published: September 2020

Abstract
Prostate cancer (PCa) remains the second most common cancer worldwide in men. Angiogenesis has been shown to play a crucial role in PCa progression in several preclinical models. Production of pro-angiogenic factors have been shown to correlate with metastasis, Gleason score and prognosis in PCa and plasma levels of VEGF were shown to be higher in patients with metastatic PCa than those with localized disease Natural killer (NK) cells, effector lymphocytes of the innate immunity, have been found to be immunosuppressed in solid cancers, including PCa. We demonstrated that NK cells in lung and colorectal cancer, acquire a pro-angiogenic phenotype, similar to NK cell within the decidua (dNK), and functionally support angiogenesis, in a TGFβ and Stat3-dependent manner.
Here, we phenotypically and functionally characterized circulating NK cells from PCa patients and their interaction with endothelial cells and macrophages. NK cell subset distribution was investigated by multicolor flow cytometry (FC) for surface antigens on peripheral blood samples PCa patients. Conditioned media (CM) from FACS-sorted PTANKs were used for functional studies of angiogenesis, on human umbilical-vein endothelial cells (HUVEC), studies for macrophage recruitment (migration assay on Boyden chambers) and polarization. Molecular studies were performed by real time PCR (qPCR) on HUCECs and macrophages exposed to CM of PTANKs. Protein arrays were performed to characterize the secretome on FACS-sorted PTANKs
We found that PTANKs acquire the pro-angiogenic/ decidual-likeCD56brightCD9+CD49a+CXCR4+ phenotype. The same phenotype was observed on cytolytic NK cells, from healthy donors, exposed to CMs of three different PCa cell lines. These results were confirmed also exposing heathy-donor derived NKs to CMs of 3 different prostate cancer cell lines (PC-3, DU-145, LNCaP), together with increased production of CXCL8, Angiogenin, Angiopoietin1 and reduced production of TNFα, IFNγ and GranzymeA. CMs from PTANKs support the formation on capillary-like structures on HUVEC, together with increased expression of VEGF, VEGR-2, CXCL8, ICAM-1 and VCAM-1. Secretome analysis revealed the ability of PTANKs release pro-angiogenic factors (CLXL8, MMP-1, MMP-9; uPAR) and cytokines/chemokines involved in macrophage recruitment (CCL1, CCL2, CCL5, CCL7, CCL13, CXCL1, CXCL11) and M2-like polarization (IL-10). Finally, CMs from PTANKs can recruit THP-1 monocyte and polarize THP-1 macrophage towards CD206, Arginase1, CXCL8-expressing M2-like/TAM phenotype.
Our results place PTANKS as effector cells able in supporting angiogenesis in PCa by directly interaction with endothelial cells and via macrophage polarization.
Citation Format: Antonino Bruno, Denisa Baci, Matteo Gallazzi, Annalisa Bosi, Angelo Naselli, Andrea Guarneri, Lorenzo Mortara, Douglas Noonan, Adriana Albini. Prostate tumor associated NK cells (PTANKs) acquire the decidual-like/pro-angiogenic phenotype and polarize macrophages towards the M2-like/TAM subset [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1581.