Abstract 6815: CXCL12-loaded-hydrogel (CLG) in vivo modifies lung metastatic niche toward an immunoactive microenvironment reducing lung metastasis development

Abstract PURPOSE and INTRODUCTION: In vivo a dermal filler hyaluronic gel-based loaded with CXCL12 (CLG) was able to divert B16-hCXCR4 cells from lung metastases. Herein, CLG was assessed for the capability to isolate human circulating cancer cells (CTCs). Moreover, in vivo CLGs and lungs were characterized to dissect natural (lung) and artificial (gel) microenvironment composition. EXPERIMENTAL DESIGN: “TRAP4MET” clinical trial was conducted in 48 advanced cancer patients characterized at diagnosis for CLG-dependent CTCs-isolation as compared to ScreenCell™ filters. C57/B6 mice were s.c. injected with Empty Gel (EG) or CLG and five days later i.v. injected with GFP-LLC (Lewis lung) cells. Lungs and gels were collected at time 0 (before tumour cells injection), after 4 hours and 10 days post tumour cells inoculation. Lungs and gels were analysed through flow-cytometry for GFP-LLC cells, innate and adaptive immunity. RESULTS: In TRAP4MET clinical trial CLG-CTCs were isolated in 8/8 patients with ovarian (OC), 6/8 with lung (LC), 6/8 with colorectal (CRC), 8/8 with endometrial (EC), 8/8 with renal (RCC) cancer and 5/8 with glioblastoma (GBM). In OC, LC and GBM, CLG isolated more CTCs than the conventional ScreenCell™ (CLG/SC ratio=1.88 for OC, 2.47 for LC and 11.89 for GBM). To dissect the in vivo efficacy of CLG, GFP-LLC were i.v. injected in C57/B6 mice five days later the s.c CLG or EG injection. Five days after CLG/EG gels and lungs were recovered. In CLG a lower % of total Macrophages (MΦ), inactive/precursor Tregs and higher % of M2-MΦ was observed compared to EG while no major differences were revealed in lungs from CLG/EG/CTRL groups. 4 hours post injection revealed in CLG a lower % of MΦ, lower inactive/precursor Tregs and a higher % of M2- MΦ and CXCR4+ MΦ versus EG. In correspondent CLG-lungs, lower % of mature neutrophils and inactive/progenitor Tregs as compared to EG-lung and CTRL-lung, respectively. 10 days post cells inoculation, CLG gels revealed again low total MΦ, low inactive/precursor Tregs and high M2-MΦ, CXCR4+ MΦ as to EG. The corresponding CLG-lungs displayed higher non-aged neutrophils and and NK cells, lower CXCR4+ MΦ, lower total neutrophils, lower aged (CXCR4+) neutrophils and lower inactive Tregs as compared to EG and CTRL, respectively. Consistently, GFP-LLC cells were higher in CLG compared to EG at either 4 hours and 10 days post cell injection while reduced in lungs of CLG-mice compared to EG- and CTRL-lungs mice at 4 hours and 10 days post cell inoculation, respectively. CONCLUSION: CLG may support OC, LC and GBM- CTC counting in cancers at today orphan of CTCs reliable methods. In vivo, CLG attracted GFL-LLC cells while reducing lung GFP-LLC cells as early as after 4 hours post cell inoculation. CLG/EG and correspondent lung analysis revealed an immunosuppressive microenvironment within CLG compared to EG reduced in the corresponding lungs. Citation Format: Giuseppe Guardascione, Luigi Portella, Dario Guido Di Febbraro, Giulia Bertolini, Giuseppina Rea, Caterina Ieranò, Crescenzo D'Alterio, Maria Napolitano, Sara Santagata, Anna Maria Trotta, Emilia Scarpa, Sabrina Chiara Cecere, Alessandro Ottaiano, Giuliano Palumbo, Alessandro Morabito, Teresa Somma, Roberto Pacelli, Sandro Pignata, Stefania Scala. CXCL12-loaded-hydrogel (CLG) in vivo modifies lung metastatic niche toward an immunoactive microenvironment reducing lung metastasis development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6815.