DPY30-H3K4me3轴介导黑色素瘤中PD-L1的表达

The DPY30-H3K4me3 Axis-Mediated PD-L1 Expression in Melanoma.

作者信息

Zhang Zhichun, Han Yixuan, Sun Qiuyue, Wang Yipeng, Sun Lichao

机构信息

Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, People's Republic of China.

Department of Rheumatology and Immunology, Affiliated Kailuan General Hospital of North China University of Science and Technology, Tangshan, People's Republic of China.

出版信息

J Inflamm Res. 2022 Sep 26;15:5595-5609. doi: 10.2147/JIR.S377678. eCollection 2022.

DOI:10.2147/JIR.S377678

PMID:36185638

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9525212/

Abstract

BACKGROUND

DPY30 is a common subunit of the human SET1/MLL complex and is an essential protein required for the activity of SET1/MLL methyltransferase. DPY30 regulates the histone H3K4 modification, and dysfunction of DPY30 might contribute to the regulation of cancer immune evasion. However, the functions and regulation of DPY30 in the expression of programmed cell death ligand 1 (PD-L1) is still not completely explored.

METHODS

Various online databases were used for data processing and visualization, including UALCAN, Oncomine, cBioPortal, SangerBox, TISIDB, TIMER, and GEPIA databases. The expression of DPY30 and PD-L1 in melanoma tissues were evaluated by IHC. Chromatin Immunoprecipitation (ChIP), RT-PCR and flow cytometry were used to elucidate the underlying molecular mechanism of PD-L1 expression regulation and its function.

RESULTS

The mRNA level of DPY30 in melanoma was higher than in normal tissues. The expression of DPY30 was positively associated with TMB, neoantigens and PD-L1 expression. Furthermore, DPY30 expression showed significant positive correlations with immune suppressor cells and ICP genes involved in T-cell exhaustion. IHC showed that the positive rates of DPY30 and PD-L1 in melanoma tissues were 62% and 58%, respectively. Correlation analysis revealed that DPY30 over-expression was positively associated with PD-L1 expression. Silencing of DPY30 by specific siRNA significantly inhibited PD-L1 expression. ChIP analysis revealed that H3K4me3 levels were enriched in the proximal PD-L1 promoter region in tumor cells. Inhibition of DPY30 still suppressed the PD-L1 level in IFN-γ treated MMAC-SF cells. Furthermore, the apoptosis of PD1 T-cells in co-culture with MMAC-SF cells by knockdown of DPY30 were markedly reduced.

CONCLUSION

This study shows the roles of DPY30 in regulating the cancer immune evasion in melanoma. Targeting the DPY30-H3K4me3 axis might be an alternative approach to enhance the efficacy of checkpoint immunotherapy.

摘要

背景

DPY30是人类SET1/MLL复合物的一个常见亚基，是SET1/MLL甲基转移酶活性所必需的蛋白质。DPY30调节组蛋白H3K4修饰，DPY30功能障碍可能有助于癌症免疫逃逸的调控。然而，DPY30在程序性细胞死亡配体1（PD-L1）表达中的功能和调控仍未完全阐明。

方法

使用各种在线数据库进行数据处理和可视化，包括UALCAN、Oncomine、cBioPortal、SangerBox、TISIDB、TIMER和GEPIA数据库。通过免疫组化评估黑色素瘤组织中DPY30和PD-L1的表达。采用染色质免疫沉淀（ChIP）、逆转录-聚合酶链反应（RT-PCR）和流式细胞术阐明PD-L1表达调控及其功能的潜在分子机制。

结果

黑色素瘤中DPY30的mRNA水平高于正常组织。DPY30的表达与肿瘤突变负荷（TMB）、新抗原和PD-L1表达呈正相关。此外，DPY30表达与免疫抑制细胞和参与T细胞耗竭的免疫检查点（ICP）基因呈显著正相关。免疫组化显示，黑色素瘤组织中DPY30和PD-L1的阳性率分别为62%和58%。相关性分析显示，DPY30过表达与PD-L1表达呈正相关。用特异性小干扰RNA（siRNA）沉默DPY30可显著抑制PD-L1表达。ChIP分析显示，肿瘤细胞中PD-L1启动子近端区域的H3K4me3水平富集。在干扰素-γ（IFN-γ）处理的MMAC-SF细胞中，抑制DPY30仍可降低PD-L1水平。此外，通过敲低DPY30，与MMAC-SF细胞共培养的PD1 T细胞的凋亡明显减少。