Evaluation of the In vivo Antitumor Activity of Polyanhydride IL-1α Nanoparticles

Summary

A standard protocol is described to study the antitumor activity and associated toxicity of IL-1α in a syngeneic mouse model of HNSCC.

Abstract

Cytokine therapy is a promising immunotherapeutic strategy that can produce robust antitumor immune responses in cancer patients. The proinflammatory cytokine interleukin-1 alpha (IL-1α) has been evaluated as an anticancer agent in several preclinical and clinical studies. However, dose-limiting toxicities, including flu-like symptoms and hypotension, have dampened the enthusiasm for this therapeutic strategy. Polyanhydride nanoparticle (NP)-based delivery of IL-1α would represent an effective approach in this context since this may allow for a slow and controlled release of IL-1α systemically while reducing toxic side effects. Here an analysis of the antitumor activity of IL-1α-loaded polyanhydride NPs in a head and neck squamous cell carcinoma (HNSCC) syngeneic mouse model is described. Murine oropharyngeal epithelial cells stably expressing HPV16 E6/E7 together with hRAS and luciferase (mEERL) cells were injected subcutaneously into the right flank of C57BL/6J mice. Once tumors reached 3-4 mm in any direction, a 1.5% IL-1a - loaded 20:80 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane:1,6-bis(p-carboxyphenoxy)hexane (CPTEG: CPH) nanoparticle (IL-1α-NP) formulation was administered to mice intraperitoneally. Tumor size and body weight were continuously measured until tumor size or weight loss reached euthanasia criteria. Blood samples were taken to evaluate antitumor immune responses by submandibular venipuncture, and inflammatory cytokines were measured through cytokine multiplex assays. Tumor and inguinal lymph nodes were resected and homogenized into a single-cell suspension to analyze various immune cells through multicolor flow cytometry. These standard methods will allow investigators to study the antitumor immune response and potential mechanism of immunostimulatory NPs and other immunotherapy agents for cancer treatment.

Introduction

One of the emerging areas of cancer immunotherapy is the use of inflammatory cytokines to activate patients' immune system against their tumor cells. Several proinflammatory cytokines (i.e., interferon-alpha (IFNα), interleukin-2 (IL-2), and interleukin-1 (IL-1)) can mount significant antitumor immunity, which has generated interest in exploring the antitumor properties as well as the safety of cytokine-based drugs. Interleukin-1 alpha (IL-1α) in particular, is a proinflammatory cytokine known as the master cytokine of inflammation¹. Since the discovery of this cytokine in the late 1970s, it has been investigated as an anticancer ....

Protocol

All the in vivo procedures used in this study were approved by the Institutional Animal Care and UseCommittee (IACUC) of the University of Iowa.

1. Preparation and maintenance of HNSCC cell line

NOTE: In this study, the murine oropharyngeal epithelial cell line stably transformed with HPV E6 and E7 together with hRas and luciferase (mEERL) will be used. This cell line was developed from C57BL/6J mouse strain and was a gift from Dr. Paola D. Vermeer (Department of Surgery, University of South Dakota Sanford School of Medicine, South Dakota, USA).

1. Thaw a frozen vial of mEERL cells in a pre-heat....

Results

In this study, the antitumor activity of polyanhydride IL-1α in a syngeneic mouse model of HNSCC was investigated. Recombinant IL-1α (rIL-1α) significantly slowed mEERL tumor growth (Figure 1A), although weight loss was observed in the treated mice, which was restored after treatment withdrawal (Figure 1B). IL-1α-NPs did not induce a significant antitumor effect compared to saline or blank-NPs (Figure 1A) and was.......

Discussion

This protocol will allow any investigator to study the antitumor activity and some of the underlying mechanisms of immunomodulatory drugs in an in vivo tumor mouse model system. Here, a syngeneic subcutaneous tumor model was used, which has several advantages over orthotopic models, including its technically straightforward protocol, easy monitoring of tumor growth, less animal morbidity, and higher producibility. Subcutaneous tumor models can also be modified to a bilateral tumor model by injecting tumor cells .......

Materials

Name	Company	Catalog Number	Comments
Bio-Plex 200 Systems	Bio-Rad		The system was provided from the Flow Cytometry Facility University of IOWA Health Care
Bio-Plex Pro Mouse Cytokine 23-plex Assay	Bio-Rad	M60009RDPD
C57BL/6J Mice	Jakson Labs	664	4 to 6 weeks old
DMEM (Dulbecco's Modified Eagle Medium)	Thermo Fisher Scientific	11965092
DMEM/Hams F12 (Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12)	Thermo Fisher Scientific	11320033
EGF	Millipore Sigma	SRP3196-500UG
Fetal Bovine Serum	Millipore Sigma	12103C-500ML
Gentamycin sulfate solution	IBI Scientific	IB02030
gentleMACS Dissociator	Miltenyi biotec
Hand-Held Magnetic Plate Washer	Thermo Fisher Scientific	EPX-55555-000
Hydrocortisone	Millipore Sigma	H6909-10ML
Insulin	Millipore Sigma	I0516-5ML
Ketamine/xylazine			Injectable anesthesia
MEERL cell line			Murine oropharyngeal epithelial cells stably expressing HPV16 E6/E7 together with hRAS and luciferase (mEERL) cells
Portable Balances	Ohaus
Scienceware Digi-Max slide caliper	Millipore Sigma	Z503576-1EA
Sterile alcohol prep pad (70% isopropyl alcohol)	Cardinal	COV5110.PMP
Transferrin Human	Millipore Sigma	T8158-100MG
Tri-iodothyronin	Millipore Sigma	T5516-1MG