Combination of radiation and interleukin 12 eradicates large orthotopic hepatocellular carcinoma through immunomodulation of tumor microenvironment

Abstract

Immunotherapies have shown promising results in certain cancer patients. For hepatocellular carcinoma (HCC), the multiplicity of an immunotolerant microenvironment within both the tumor, and the liver per se may limit the efficacy of cancer immunotherapies. Since radiation induces immunogenic cell death and inflammatory reactions within the tumor microenvironment, we hypothesized that a combination therapy of radiation and lasting local immunostimulating agents, achieved by intratumoral injection of an adenoviral vector encoding interleukin 12, may reverse the immunotolerant microenvironment within a well-established orthotopic HCC toward a state favorable for inducing antitumor immunities. Our data showed that radiation and IL-12 combination therapy (RT/IL-12) led to dramatic tumor regression in animals bearing large subcutaneous or orthotopic HCC, induced systemic effect against distant tumor, and significantly prolonged survival. Radiation monotherapy induced tumor regression at early times but afterwards most tumors regained exponential growth, while IL-12 monotherapy only delayed tumor growth. Mechanistic studies revealed that RT/IL-12 increased expression of MHC class II and co-stimulatory molecules CD40 and CD86 on tumor-infiltrating dendritic cells, suggesting an improvement of their antigen presentation activity. RT/IL-12 also significantly reduced accumulation of tumor-infiltrating myeloid-derived suppressor cells (MDSCs) and impaired their suppressive functions by reducing production of reactive oxygen species. Accordingly, tumor-infiltrating CD8+ T cells and NK cells were significantly activated toward the antitumor phenotype, as revealed by increased expression of CD107a and TNF-α. Together, our data showed that RT/IL-12 treatment could reset the intratumoral immunotolerant state and stimulate activation of antitumor cellular immunity that is capable of eliminating large established HCC tumors.

Localized Interleukin-12 for Cancer Immunotherapy

“…In another study, radiation along with an i.t. injection of an IL-12-encoding adenoviral vector greatly reduced tumor growth and metastasis compared to either treatment alone in a BNL-P2 hepatocellular carcinoma model, while a near-complete abscopal response occurred in a CT26 colorectal cancer model (383). An abscopal response was also induced in a fully humanized rhabdomyosarcoma xenograft model.…”

IFN-γ: A cytokine at the right time, is in the right place

“…Systemic administration of IL-12 has shown limited success, with numerous adverse events being observed in clinical trials, likely a consequence of off-target effects, as well as poor pharmacokinetics [182][183][184]. To target IL-12 expression to the tumor microenvironment, plasmids encoding IL-12 have been introduced via electroporation [185,186], intratumoral injection of viral vectors encoding IL-12 [187], engineered tumorspecific T cells expressing IL-12 [188][189][190][191][192][193][194][195] and intratumoral injection of microspheres containing slow-release IL-12 [196,197]. Recent attention has been given to an IL-12-fused anti-his-tone antibody (NHS-IL12) which targets sites of cell necrosis where free cellular DNA is abundant.…”

Immunotherapy as sensitizer for local radiotherapy

“…right quadriceps muscle C57Bl/6 mice +/+ Leg – 3.6 Gy/2x NHS-IL2 CR 80 to 100% 2 Upregulated expression of effector T cells (CD3, CD4, CD8, CD25) Schölch 21 2015 pancreatic adenocarcinoma cell lines: Panc-1 a+ BxPC3 Colorectal carcinoma cell lines HT29, HCT-116, and CT26 s.c. in the right flank BALB/c fg+ C57Bl/6 mice +/+ Flank – 10 Gy/5x Toll-like receptor 7/8 agonists CR: 50% 2 Upregulate antigen-presenting activity of dendritic cells + T cells Connolly 22 2016 Colon38, Glioma261, Line1 i.m. left leg C57BL/6 + BALB/cJ mice +/+ Leg – 15 Gy / 1x CCR2/CCR5 antagonist CR: 40% 2 Increase of circulating + intratumoral inflammatory monocytes, chemokines; promote migration of myeloid cells, upregulation of CCL2 and CCL5 transcripts Wu 23 2018 BNL-P2 HCC cells s.c. in the right flank Balb/c mice +/+ Flank – 10 Gy/1x adenoviral vector +,IL 12 CR: 40%; PR: 50% 2 expression of MHC class II + CD40, CD86 on tumor-infiltrating dendritic cells Zhuang 24 2018 Lewis lung carcinoma -cells s.c. in the right leg C57BL/6mice +/+ Leg – 8 Gy/1x CpG (intratumoral), Anti-PD-1 CR: 100% 2 …”