Abstract：OBJECTIVE To modify the resiquimod(R848) liposomes with mannose to improve its immunotherapeutic effect on mouse tumors through endowing it with active targeting ability to tumor-associated macrophages(TAMs). METHODS The mannose-modified R848 liposomes(M-LS/R848)were prepared by mixing Mannase-PEG2000-DSPE into lipid and encapsulating R848 with a pH gradient driving drug loading method. The physicochemical properties of M-LS/R848 were characterized by laser particle sizer and transmission electron microscope, and the R848 release was analyzed by a dialysis method. In vitro, the targeting of M-LS/R848 to mouse macrophage RAW 264.7 was analysed. In vivo, the tumor-homing and immunotherapy effect of M-LS/R848 were evaluated on MC38 tumor models, and its therapeutic mechanism was investigated by immunofluorescence staining. RESULTS The M-LS/R848 liposomes prepared in this study were uniform spherical particles, with an average diameter of (123.43±2.43) nm and Zeta potential of(-0.33±0.24) mV. The R848 encapsulation rate of M-LS/R848 is (85.59±0.37)% with a release rate of 46.8% in 48 h. In vitro targeting experiments showed that the uptake rate of M-LS/R848 by RAW264.7 cells was (5.29±0.16)%, which significantly higher than that of LS/R848 . In vivo tumor targeting analysis revealed that the accumulation of mannose-modified liposomes in MC38 tumors was significantly higher than that of non-modified liposomes. The antitumor experiments showed that the average tumor volume and weights of the M-LS/R848-treated group were significantly smaller than that of the LS/R848-treated group, and even two mice were cured and immune to the reinoculation of MC38 tumors. Immunofluorescence analysis revealed that M1-type macrophages and CD8 positive cells in tumor tissues of M-LS/R848-treated group were significantly increased compared with the LS/R848 group. CONCLUSION Modifying R848 liposome with mannose could effectively improve its tumor targeting ability and enhance its immunotherapy effect.
WILLINGHAM S B, VOLKMER J P, GENTLES A J, et al. The CD47-signal regulatory protein alpha(SIRPa)interaction is a therapeutic target for human solid tumors. Proc Natl Acad Sci, 2012, 109(17): 6662-6667.
FREGA G, WU Q, LE NAOUR J, et al. Trial watch: experimental TLR7/TLR8 agonists for oncological indications. Oncoimmunology, 2020, 9(1): 1796002. Doi:10.1080/2162402X.2020.1796002.
ZHANG H, TANG W L, KHEIROLOMOOM A, et al. Development of thermosensitive resiquimod-loaded liposomes for enhanced cancer immunotherapy. J Controlled Release, 2021, 330: 1080-1094.
HEMMI H, KAISHO T, TAKEUCHI O, et al. Small anti-viral compounds activate immune cells via the TLR7 MyD88-dependent signaling pathway. Nat Immunol, 2002, 3(2): 196-200.
BRONTE V, MURRAY P J. Understanding local macrophage phenotypes in disease: modulating macrophage function to treat cancer. Nat Med, 2015, 21(2): 117-119.
ADVANI R, FLINN I, POPPLEWELL L, et al. CD47 blockade by Hu5F9-G4 and rituximab in non-Hodgkin′s lymphoma. New Engl J Med, 2018, 379(18): 1711-1721.
RODELL C B, ARLAUCKAS S P, CUCCARESE M F, et al. TLR7/8-agonist-loaded nanoparticles promote the polarization of tumour-associated macrophages to enhance cancer immunotherapy. Nat Biomed Eng, 2018, 2(8): 578-588.
HU M, ZHANG J, YU Y, et al. Injectable liquid crystal formation system for reshaping tumor immunosuppressive microenvironment to boost antitumor immunity: postoperative chemoimmunotherapy. Small, 2020, 16(50): 2004905. Doi:10.1002/smll.202004905
ZHOU Z, SUN L. Immune effects of R848: evidences that suggest an essential role of TLR7/8-induced, Myd88-and NF-κB-dependent signaling in the antiviral immunity of Japanese flounder (Paralichthys olivaceus). Dev Comp Immunol, 2015, 49(1): 113-120.
WEISKOPF K, RING A M, HO C C M, et al. Engineered SIRPα variants as immunotherapeutic adjuvants to anticancer antibodies. Science, 2013, 341(6141): 88-91.
BOZZUTO G, MOLINARI A. Liposomes as nanomedical devices. Int J Nanomed, 2015, 10: 975-999.
FEDERICO C, ALHALLAK K, SUN J, et al. Tumor microenvironment-targeted nanoparticles loaded with bortezomib and ROCK inhibitor improve efficacy in multiple myeloma. Nat Commun, 2020, 11(1): 1-13.
NI K, LUO T, CULBERT A, et al. Nanoscale metal–organic framework co-delivers TLR-7 agonists and anti-CD47 antibodies to modulate macrophages and orchestrate cancer immunotherapy. J Am Chem Soc, 2020, 142(29): 12579-12584.
BAHMANI B, GONG H, LUK B T, et al. Intratumoral immunotherapy using platelet-cloaked nanoparticles enhances antitumor immunity in solid tumors. Nat Commun, 2021, 12(1): 1-12.
LIU Y Y, LUO Y Y, DENG S Q, et al. Preparation and evaluation of human serum albumin modified irinotecan hydrochloride PLGA Nanoparticles. J Chin Pharm Sci(中国药学英文版), 2021, 56(21):1740-1748.
LI H, SOMIYA M, KURODA S. Enhancing antibody-dependent cellular phagocytosis by re-education of tumor-associated macrophages with resiquimod-encapsulated liposomes. Biomaterials, 2021, 268: 120601. Doi:10.1016/j.biomaterials.2020.120601.
GOLDBERG M S. Improving cancer immunotherapy through nanotechnology. Nat Rev Cancer, 2019, 19(10): 587-602.
CHEN Q, WANG C, ZHANG X, et al. In situ sprayed bioresponsive immunotherapeutic gel for post-surgical cancer treatment. Nat Nanotechnol, 2019, 14(1): 89-97.
LI Y, GAO L, LI H C, et al. M2 macrophage marker CD206 and tumor. Int J Oncol, 2019, 46(3):174-177.
YE J, YANG Y, JIN J, et al. Targeted delivery of chlorogenic acid by mannosylated liposomes to effectively promote the polarization of TAMs for the treatment of glioblastoma. Bioact Mater, 2020, 5(3): 694-708.
TIAN B, LIU R, CHEN S, et al. Mannose-coated gadolinium liposomes for improved magnetic resonance imaging in acute pancreatitis. Int J Nanomed, 2017, 12: 1127-1141.
OVAIS M, GUO M, CHEN C. Tailoring nanomaterials for targeting tumor-associated macrophages. Adv Mater, 2019, 31(19): 1808303. Doi:10.1002/adma.201808303.
FIGUEIREDO P, LEPLAND A, SCODELLER P, et al. Peptide-guided resiquimod-loaded lignin nanoparticles convert tumor-associated macrophages from M2 to M1 phenotype for enhanced chemotherapy. Acta Biomater, 2021, 133: 231-243.
XU L K, CAO D Y. Research and application of active drug loading method to prepare drug liposomes. J Hebei Med Univ(河北医科大学学报), 2005, 26(5): 390-392.
ROEMELING C A, WANG Y, QIE Y, et al. Therapeutic modulation of phagocytosis in glioblastoma can activate both innate and adaptive antitumour immunity. Nat Commun, 2020, 11(1): 1-12.
CASSETTA L, POLLARD J W. Targeting macrophages: therapeutic approaches in cancer. Nat Rev Drug Discov, 2018, 17(12): 887-904.
PATHRIA P, LOUIS T L, VARNER J A. Targeting tumor-associated macrophages in cancer. Trends Immunol, 2019, 40(4): 310-327.