RESUMO
As a pivotal defensive line against multitudinous malignant tumors, natural killer (NK) cells exist in the tumor microenvironment (TME). RAD18 E3 Ubiquitin Protein Ligase (RAD18) has been reported to foster the malignant progression of multiple cancers, but its effect on NK function has not been mined. Here, the study was designed to mine the mechanism by which RAD18 regulates the killing effect of NK cells on colorectal cancer (CRC) cells. Expression of E2F Transcription Factor 7 (E2F7) and RAD18 in CRC tissues, their correlation, binding sites, and RAD18 enrichment pathway were analyzed by bioinformatics. Expression of E2F7 and RAD18 in cells was assayed by qRT-PCR and western blot. Dual-luciferase assay and chromatin immunoprecipitation (ChIP) assay verified the regulatory relationship between E2F7 and RAD18. CCK-8 assay was utilized to assay cell viability, colony formation assay to detect cell proliferation, lactate dehydrogenase (LDH) test to assay NK cell cytotoxicity, ELISA to assay levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and immunofluorescence to detect expression of toxic molecules perforin and granzyme B. High expression of RAD18 and E2F7 was found in CRC tissues and cells. Silencing RAD18 could hamper the proliferation of CRC cells, foster viability and cytotoxicity of NK cells, and increase the secretion of GM-CSF, TNF-α, IFN-γ as well as the expression of perforin and granzyme B. Additionally, ChIP and dual-luciferase reporter assay ascertained the binding relationship between RAD18 promoter region and E2F7. E2F7 could activate the transcription of RAD18, and silencing RAD18 reversed the inhibitory effect of E2F7 overexpression on NK cell killing. This work clarified the inhibitory effect of the E2F7/RAD18 axis on NK cell killing in CRC, and proffered a new direction for immunotherapy of CRC in targeted immune microenvironment.
RESUMO
Interleukins (ILs) are involved in the occurrence and development of numerous types of cancer, and serve a critical role in the development of effective cancer therapeutics. The aim of the present study was to investigate the effect of IL-27 on chemotherapy resistance in lung cancer cells, and analyze its potential molecular mechanism in lung cancer tissues. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were performed to examine the RNA and protein expression levels of IL-27. A Cell Counting Kit-8 assay was performed to evaluate the proliferation rates of the lung cancer line A549. Flow cytometry was subsequently applied to determine the rate of apoptosis in A549 cells. The data obtained revealed that the expression of IL-27 with cisplatin, significantly suppressed the proliferation and apoptosis of A549 cells compared with that in the cisplatin treatment group alone. The expression of Akt and apoptosis factors such as Caspase-3 and Bcl-2/Bax also ascertained that upregulated IL-27 inhibited the development of cancer and increased apoptosis in the A549 cells. Therefore, IL-27 may represent a potential target for antitumor therapy, especially when considering the clinical challenges presented by the development of chemoresistance in tumors. These findings suggest that IL-27 is a promising biomarker and represents a novel treatment strategy for patients with lung cancer.
