Theranostics 2017; 7(15):3732-3744. doi:10.7150/thno.20251
The Anti-Tumor Effects of M1 Macrophage-Loaded Poly (ethylene glycol) and Gelatin-Based Hydrogels on Hepatocellular Carcinoma
1. School of Pharmacy, Division of Pharmaceutical Sciences, Pharmacy Practice Division, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA;
2. Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong SAR; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, China;
3. Chemical Biology Centre, The University of Hong Kong, Pokfulam, HKSAR.
* Co-First Authors
Background and Aims: Recently we reported that direct injection of M1 macrophages significantly caused tumor regression in vivo. Despite the promising result, a major limitation in translating this approach is the induction of acute inflammatory response. To improve the strategy, a biocompatible scaffold for cell presentation and support is essential to control cell fate. Here, we aimed to elucidate the anti-tumor effects of a poly(ethylene glycol) diacrylate (PEGdA) and thiolated gelatin poly(ethylene glycol) (Gel-PEG-Cys) cross-linked hydrogels capsulated with M1 macrophages in both in vitro and in vivo disease models.
Methods: Hydrogels were made at 0.5% (w/v) Iragcure 2959 photoinitiator, 10% (w/v) PEGdA, and 10% (w/v) Gel-PEG-Cys. Monocytic THP-1 cells were loaded into hydrogels and differentiated into M1 macrophages with lipopolysaccharide (LPS) and interferon gamma (IFN-γ). The M1 hydrogels were then cocultivated with HCC cell-lines Hep3B and MHCC97L to investigate the anti-tumor capacities and the associated molecular profiles in vitro. A nude mice ectopic liver cancer model with dorsal window chamber (DWC) and a subcutaneous tumor model were both performed to validate the in vivo application of M1 hydrogels.
Results: M1 hydrogels significantly decreased the viability of HCC cells (MHCC97L: -46%; Hep3B: -56.9%; P<0.05) compared to the control in vitro. In response to HCC cells, the hydrogel embedded M1 macrophages up-regulated nitrite and tumor necrosis factor alpha (TNF-α) activating caspase-3 induced apoptosis in the tumor cells. Increased tumor necrosis was observed in DWC filled with M1 hydrogels. In addition, mice treated with M1 hydrogels exhibited a significant 2.4-fold decrease in signal intensity of subcutaneous HCC tumor compared to control (P=0.036).
Conclusion: M1 hydrogels induced apoptosis in HCC cells and tumor regression in vivo. Continuous development of the scaffold-based cancer immunotherapy may provide an alternative and innovative strategy against HCC.
Keywords: Hepatocellular carcinoma, M1 hydrogels, M1 macrophages, Hydrogels, Animal Model.
Guerra AD, Yeung OWH, Qi X, Kao WJ, Man K. The Anti-Tumor Effects of M1 Macrophage-Loaded Poly (ethylene glycol) and Gelatin-Based Hydrogels on Hepatocellular Carcinoma. Theranostics 2017; 7(15):3732-3744. doi:10.7150/thno.20251. Available from http://www.thno.org/v07p3732.htm