Silencing of Perilipin 3 Inhibits Lung Adenocarcinoma Cell Immune Resistance by Regulating the Transcription of PD-L1 Through c-Myc.

BACKGROUND: Perilipin 3 (PLIN3), a lipid droplet-associated protein, is found to be highly expressed in human cancers. This study aimed to investigate the biological functions and underlying mechanism of PLIN3 in lung adenocarcinoma (LUAD). METHODS: To analyse PLIN3 expression in normal and cancerous tissues, relevance between PLIN3 expression and survival prognosis, and to predict the pathways related to PLIN3, bioinformatic analysis was performed. In A549 and H1299 cells, qRT-PCR or western blotting was used to determine mRNA/protein expression of PLIN3, PD-L1, and c-Myc. In A549 and H1299 cells, CCK-8 assay, EdU, and flow cytometry were used to assess cell viability, proliferation, and apoptosis. Chip and luciferase reporter assays were performed to verify the binding of PD-L1 with c-Myc. The functions of PLIN3 were examined in vivo in a xenograft tumor model. RESULTS: In LUAD tissues and cells, PLIN3 expression was downregulated. A shorter survival time was observed in patients with high PLIN3 expression than in patients with low PLIN3 expression. Silencing of PLIN3 inhibited cell proliferation, PD-L1 expression, and Myc pathway, as well as induced apoptosis in LUAD cells. c-Myc acts as a transcription factor of PD-L1. Moreover, the inhibitory actions of PLIN3 silencing on c-Myc and PD-L1 expression as well as cell proliferation and stimulatory action of PLIN3 silencing on cell apoptosis were reversed by c-Myc overexpression. In vivo, PLIN3 silencing inhibited the growth of xenograft tumour and reduced PLIN3, PD-L1, and c-Myc protein expression. CONCLUSION: Silencing of PLIN3 inhibited tumour growth by regulating the Myc/PD-L1 pathway.

1. Silencing of PLIN3 inhibited tumour growth in vivo and in vitro.2. Silencing of PLIN3 inhibited PD-L1 expression and Myc pathway in LUAD cells.3. c-Myc acted as a transcription factor of PD-L1.4. Silencing of PLIN3 exerted anti-tumour effects by regulating c-Myc/PD-L1.

MicroRNA-325 facilitates atherosclerosis progression by mediating the SREBF1/LXR axis via KDM1A.

AIMS: MicroRNA-325 (miR-325) was significantly upregulated in diabetic atherosclerosis, while its specific role in atherosclerosis has not been established. The present study was set to probe the effects of miR-325 on the atherosclerosis progression and to explore the mechanisms. MATERIALS AND METHODS: The ApoE-/- mouse with atherosclerosis was developed to detect the miR-325 expression in atherosclerotic plaques. The pathological symptoms of atherosclerotic mice were observed by injection of miR-325 mimic or inhibitor. Subsequently, the levels of CRP, IL-6, IL-1ß and TNF-ɑ in mouse serum were measured by ELISA. Then, miR-325 was overexpressed or silenced in RAW264.7-derived foam cells (FCs), and cholesterol efflux and lipid content were evaluated. Furthermore, miR-325 expression was altered in HA-VSMCs to measure viability and apoptosis. The targets of miR-325 were predicted in a bioinformatics website, and the expression of KDM1A, SREBF1 and PPARγ-LXR-ABCA1 in mouse arterial tissues and cells was detected, followed by rescue experiments. KEY FINDINGS: miR-325 was elevated in arterial tissues of atherosclerotic mice, and miR-325 inhibition in mice reduced the contents of total cholesterol, triglyceride, low-density lipoprotein, and CRP, IL-6, IL-1ß and TNF-ɑ levels in mouse serum. miR-325 inhibitor facilitated the cholesterol efflux and decreased the lipid content in RAW264.7 cells, and also diminished HA-VSMC viability. miR-325 targeted KDM1A to reduce SREBF1 expression, and further KDM1A suppression inhibited cholesterol efflux in RAW264.7 cells and the activation of PPARγ-LXR-ABCA1 pathway. SIGNIFICANCE: miR-325 lowers SREBF1 expression by decreasing KDM1A expression, thereby inhibiting the activation of the PPARγ-LXR-ABCA1 pathway and thus promoting atherosclerosis.

Negative feedback of NF-κB signaling by long noncoding RNA MALAT1 controls lipopolysaccharide-induced inflammation injury in human lung fibroblasts WI-38.

The study was designed to elucidate the regulatory mechanism of long noncoding RNA human metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in lipopolysaccharides (LPS)-caused inflammation injury in human lung fibroblasts WI-38. WI-38 cells were stimulated with LPS to construct acute pneumonia cell model. MALAT1 in LPS-stimulated WI-38 cells was examined. LPS-induced inflammation injury was estimated using viability, apoptosis, and cytokine secretion including interleukin-1ß (IL-1ß) and IL-6. Furthermore, the modulatory relations of MALAT1 and nuclear factor-kappa B (NF-κB) signaling were explored. We found that the sensitivity of WI-38 cells to apoptosis was enhanced by LPS-caused inflammation. Moreover, LPS promoted MALAT1 expression which was found to alleviate LPS-caused damages. Besides, NF-κB p65 overexpression resulted in an increased expression of MALAT1, and MALAT1 was identified as a target gene of p65. Furthermore, overexpression of MALAT1 reduced NF-κB activation. Pulldown assay showed that MALAT1 could directly interact with p65. Taken together, our findings revealed that MALAT1 was upregulated in LPS-stimulated WI-38 cells. Through directly interacting with p65, MALAT1 blocked LPS-caused activation of NF-κB and repressed LPS-induced inflammation injury. MALAT1 may serve as a potential diagnostic indicator or therapeutic target for pneumonia.

Cullin7 is required for lung cancer cell proliferation and is overexpressed in lung cancer.

Ubiquitin ligase Cullin7 has been identified as an oncogene in some malignant diseases such as choriocarcinoma and neuroblastoma. However, the role of Cullin7 in lung cancer carcinogenesis remains unclear. In this study, we explored the functional role of Cullin7 in lung cancer cell proliferation and tumorigenesis and determined its expression profile in lung cancer. Knocking down Cullin7 expression by small interfering RNA (siRNA) in lung cancer cells inhibited cell proliferation and elevated the expression of p53, p27, and p21 proteins. The enhanced p53 expression resulted from activation of the DNA damage response pathway. Cullin7 knockdown markedly suppressed xenograft tumor growth in vivo in mice. Moreover, Cullin7 expression was increased in primary lung cancer tissues of humans. Thus, Cullin7 is required for sustained proliferation and survival of tumor cells in vitro and in vivo, and its aberrant expression may contribute to the pathogenesis of lung cancer. Thus, our study provided evidence that Cullin7 functions as a novel oncogene in lung cancer and may be a potential therapeutic target for lung cancer management.

Variance of TNFAIP8 expression between tumor tissues and tumor-infiltrating CD4+ and CD8+ T cells in non-small cell lung cancer.

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) has been recently documented in various malignancies, but its role in non-small cell lung cancer (NSCLC) remains uncertain. In the current study, we investigated the level of TNFAIP8 in NSCLC tissues, adjacent noncancerous lung tissues, healthy lung tissues, CD4+ T cells, and CD8+ T cells by real-time reverse transcription PCR (RT-PCR) and Western blot analysis. Results revealed that the mRNA level of TNFAIP8 was significantly increased in cancer tissue than in healthy lung tissue from donors (p < 0.001). Interestingly, adjacent noncancerous lung tissues also showed higher mRNA level of TNFAIP8 than healthy lung tissue from donors (p < 0.01). Similarly, protein level of TNFAIP8 was elevated in NSCLC tissues and adjacent noncancerous lung tissues. We further analyzed TNFAIP8 expression in CD4+ T cells and CD8+ T cells. Data demonstrated that both mRNA level and protein level were significantly decreased in tumor-infiltrating CD4+ and CD8+ T cells than in peripheral CD4+ and CD8+ T cells. Moreover, patients with advanced stages presented lower protein expression of TNFAIP8 in tumor-infiltrating CD8+ T cells than patients with primary stages (p < 0.05). These results provide evidence that TNFAIP8 plays critical roles in NSCLC and may be used as a therapeutic target for the disease.