IL-27 Mediates PD-L1 Expression and Release by Human Mesothelioma Cells

Rewiring the T cell-suppressive cytokine landscape of the tumor microenvironment: a new frontier for precision anti-cancer therapy

T lymphocytes that infiltrate the tumor microenvironment (TME) often fail to function as effective anti-cancer agents. Within the TME, cell-to-cell inhibitory interactions play significant roles in dampening their anti-tumor activities. Recent studies have revealed that soluble factors released in the TME by immune and non-immune cells, as well as by tumor cells themselves, contribute to the exacerbation of T cell exhaustion. Our understanding of the cytokine landscape of the TME, their interrelationships, and their impact on cancer development is still at its early stages. In this review, we aim to shed light on Interleukin (IL) -6, IL-9, and IL-10, a small group of JAK/STAT signaling-dependent cytokines harboring T cell-suppressive effects in the TME and summarize their mechanisms of action. Additionally, we will explore how advancements in scientific research can help us overcoming the obstacles posed by cytokines that suppress T cells in tumors, with the ultimate objective of stimulating further investigations for the development of novel therapeutic strategies to counteract their tumor-promoting activities.

Targeting the NAT10/NPM1 axis abrogates PD-L1 expression and improves the response to immune checkpoint blockade therapy

BACKGROUND

PD-1/PD-L1 play a crucial role as immune checkpoint inhibitors in various types of cancer. Although our previous study revealed that NPM1 was a novel transcriptional regulator of PD-L1 and stimulated the transcription of PD-L1, the underlying regulatory mechanism remains incompletely characterized.

METHODS

Various human cancer cell lines were used to validate the role of NPM1 in regulating the transcription of PD-L1. The acetyltransferase NAT10 was identified as a facilitator of NPM1 acetylation by coimmunoprecipitation and mass spectrometry. The potential application of combined NAT10 inhibitor and anti-CTLA4 treatment was evaluated by an animal model.

RESULTS

We demonstrated that NPM1 enhanced the transcription of PD-L1 in various types of cancer, and the acetylation of NPM1 played a vital role in this process. In particular, NAT10 facilitated the acetylation of NPM1, leading to enhanced transcription and increased expression of PD-L1. Moreover, our findings demonstrated that Remodelin, a compound that inhibits NAT10, effectively reduced NPM1 acetylation, leading to a subsequent decrease in PD-L1 expression. In vivo experiments indicated that Remodelin combined with anti-CTLA-4 therapy had a superior therapeutic effect compared with either treatment alone. Ultimately, we verified that the expression of NAT10 exhibited a positive correlation with the expression of PD-L1 in various types of tumors, serving as an indicator of unfavorable prognosis.

CONCLUSION

This study suggests that the NAT10/NPM1 axis is a promising therapeutic target in malignant tumors.

Effects of Jianpi Huayu Decoction on Th1/Th2 Immune Balance in Mice With Liver Cancer-Related Fatigue via the IL- 27/STAT1 Signaling Pathway

Objective: The Chinese medicine Jianpi-Huayu decoction (, JPHY) can alleviate cancer-related fatigue in patients with liver cancer. However, its mechanism remains unclear. In this study, we used BALB/c mice with liver cancer model to investigate whether JPHY alleviates cancer-related fatigue by regulating Th1/Th2 immune balance; and the possible association with the IL-27/STAT1 signaling pathway. Methods: We established a mouse model of liver cancer fatigue. Mice were gavaged with physiological saline, low, medium, or high concentrations of JPHY respectively; and intraperitoneal injection of fludarabine (STAT1 pathway inhibitor) with JPHY for 21 days. We recorded the general condition of the mice, and assessed fatigue using scoring criteria and Exhausted Swimming Test. We calculated the spleen and thymus indices, performed H&E staining and immunohistochemical analysis on liver tumor tissues to observe the tumor proliferation marker ki67. We quantified the secretion levels of IFN-γ and IL-2 produced by Th1 cells in serum and splenic lymphocytes, as well as the secretion of IL-4, IL-10 by Th2 cells, and IL-27 in the signaling pathway through ELISA analysis. We evaluated the expression levels of p-STAT1 and STAT1 in spleen tissues using Western blot analysis. Results: JPHY exhibits a therapeutic effect on hepatocellular carcinoma-induced splenomegaly in murine models by upregulating the pro-inflammatory cytokines IFN-γ and IL-2 and downregulating the anti-inflammatory cytokines IL-4 and IL-10. Moreover, JPHY suppresses ki67 expression, reduces tumor-related inflammation infiltration, and ameliorates cancer-associated fatigue. Additionally, the expression of phosphorylated protein p-STAT1 is down-regulated. Conclusion: JPHY may improve the Th1/Th2 immune balance through its anti-inflammatory effects and promotion of IL-27-induced STAT1 phosphorylation, thereby alleviating fatigue in mice with liver cancer.

Immune marker expression of irradiated mesothelioma cell lines

Background

Though immune checkpoint inhibition has recently shown encouraging clinical efficacy in mesothelioma, most patients do not respond. Combining immune checkpoint inhibition with radiotherapy presents an attractive option for improving treatment responses owing to the various immunomodulatory effects of radiation on tumors. However, the ideal dosing and scheduling of combined treatment remains elusive, as it is poorly studied in mesothelioma. The present study characterizes the dose- and time-dependent changes to expression of various immune markers and cytokines important to antitumor responses following irradiation of mesothelioma cell lines.

Methods

Two murine (AB1, AE17) and two human (BYE, JU77) mesothelioma cell lines were treated with titrated gamma-radiation doses (1-8 Gy) and the expression of MHC class-I, MHC class-II and PD-L1 was measured over a series of post-irradiation timepoints (1-72 hours) by flow cytometry. Levels of cytokines IL-1α, IL-1β, IL-6, IL-10, IL-12p70, IL-17A, IL-23, IL-27, MCP-1, IFN-β, IFN-γ, TNF-α, and GM-CSF were measured by multiplex immunoassay in murine cell lines following 8 Gy radiation.

Results

Following irradiation, a dose-dependent upregulation of MHC-I and PD-L1 was observed on three of the four cell lines studied to varying extents. For all cell lines, the increase in marker expression was most pronounced 72 hours after radiation. At this timepoint, increases in levels of cytokines IFN-β, MCP-1 and IL-6 were observed following irradiation with 8 Gy in AB1 but not AE17, reflecting patterns in marker expression.

Conclusions

Overall, this study establishes the dose- and time-dependent changes in immune marker expression of commonly studied mesothelioma cell lines following radiation and will inform future study into optimal dosing and scheduling of combined radiotherapy and immune checkpoint inhibition for mesothelioma.