Zinc Oxide Nanoparticle–Poly I:C RNA Complexes: Implication as Therapeutics against Experimental Melanoma

Abstract

There is current interest in harnessing the combined anticancer and immunological effect of nanoparticles (NPs) and RNA. Here, we evaluate the bioactivity of poly I:C (pIC) RNA, bound to anticancer zinc oxide NP (ZnO-NP) against melanoma. Direct RNA association to unfunctionalized ZnO-NP is shown by observing change in size, zeta potential, and absorption/fluorescence spectra upon complexation. RNA corona was visualized by transmission electron microscopy (TEM) for the first time. Binding constant (K = 1.6-2.8 g L) was determined by modified Stern-Volmer, absorption, and biological surface activity index analysis. The pIC-ZnO-NP complex increased cell death for both human (A375) and mouse (B16F10) cell lines and suppressed tumor cell growth in BALB/C-B16F10 mouse melanoma model. Ex vivo tumor analysis indicated significant molecular activity such as changes in the level of phosphoproteins JNK, Akt, and inflammation markers IL-6 and IFN-γ. High throughput proteomics analysis revealed zinc oxide and poly I:C-specific and combinational patterns that suggested possible utility as an anticancer and immunotherapeutic strategy against melanoma.

Comparative Molecular Immunological Activity of Physiological Metal Oxide Nanoparticle and its Anticancer Peptide and RNA Complexes

“…In a relatively recent report we reviewed the molecular cell immunology of the metastatic tumor niche and the cytokines which are thought to regulate it [3]. We previously characterized the interaction of poly I:C to ZnO to form poly I:C-ZnO nano-complexes [34] and consistent with another recent study [4], demonstrated inhibition of experimental melanoma in B16F10-BALB/c mice by poly I:C-ZnO nano-complexes relative to ZnO NP or poly I:C controls [13]. Analysis of the poly I:C-ZnO-treated tumors relative to control mice receiving sham PBS intratumoral injection in this immuno-competent B16F10-BALB/c mouse model demonstrates significant antitumor cytokine response (Table 1).…”

“…In this experiment we compared ZnO to nickel oxide (NiO) or magnesium oxide (MgO) NP, where our group and one other have shown that these compositions may be able to functionally load protein or protein-RNA complexes onto their surfaces [32][33][34], making their baseline immunogenicity of great interest as a potential carrier of peptide/protein or RNA-based immuno-therapeutics. Based on earlier dose ranging experiments and our experience, splenocytes were incubated with a 20 µg/mL dose of ZnO, MgO, or NiO NP [9,10,13,31,33]. Splenocytes were isolated from the mouse spleen, exposed to concentrations and stained with propidium iodide (PI) and the cell populations separated and counted by flow cytometry (Figure 2).…”

“…Our lab reported that nanoparticle delivery of tuberculosis antigen 85B induced IL-2 as a bio-marker of antigen presentation in a T cell co-culture assay [9]. We noted molecular and cellular immunogenic activation upon nanoparticle exposure in the ex vivo splenocyte assay [10] or after direct intradermal or intratumoral administration [11][12][13]. Therefore here we endeavored to compare the molecular immunogenicity of zinc, cobalt, magnesium, and nickel oxide NP, finding that the ZnO NP generated superior immunogenicity in these in vitro and ex vivo assays.…”

Preparation and property of starch nanoparticles reinforced aldehyde–hydrazide covalently crosslinked PNIPAM hydrogels

“…In vitro cytotoxicity test of precursors of hydrogels, fillers of SNPs and H 9.0 hydrogel were assayed using a CCK‐8 assay with L929 fibroblasts cells over 7 days . Results were shown in Figure .…”

The era of bioengineering: how will this affect the next generation of cancer immunotherapy?

“…Significant results in terms of cytokine production and positive therapeutic outcome in mice have also been recorded with nanoparticle-mediated IL-12 gene therapy [16]. In addition, nanoparticle encapsulation has been reported for IL-2 [18–20], IL-15 [21], IL-10 siRNA [22], GM-CSF [23, 24], and the toll-like receptor (TLR) agonists CpG oligodeoxynucleotides (CpG-ODN) [25–27] and Poly I:C [28, 29], with positive outcomes in mouse models (Table 1). All these studies collectively confirmed the previous assumption that nanoparticle formulations are safer and induce better therapeutic effects than their free-soluble counterparts due to controlled local administration and higher concentration at the tumor site in virtue of the EPR effect.…”