Activation of astrocytes by ANXA2-derived extracellular vesicles from lung cancer cells affects aggressiveness, immunotherapy response and microenvironment of lung cancer.

Background: ANXA2 has been extensively documented in relation to cancer. Nevertheless, the involvement of ANXA2 in lung carcinoma remains uncertain. Methods: Data from The Cancer Genome Atlas (TCGA) database was downloaded using open-access methods. The examination of publicly available data was conducted utilizing the R software. The mRNA level of specific molecules was detected using Real-time Quantitative PCR (qPCR). The protein level of specific molecules was detected using the Western blot assay. The cell proliferation ability of cancer cells was assessed using the CCK8 assay. The invasion and migration capability of cancer cells was assessed using the Transwell assay. Validation of exosomes extraction was conducted using electron microscopy and particle size analysis. Results: In this study, based on series experiments, we found that ANXA2 can promote the activation of neuroastrocytes cells CP-H122 through the exosome pathway. Also, we found that ANXA2 can be transmitted from A549 cells to CP-H122 through the exosomes pathway and further promote the activation of CP-H122. Activated CP-H122 cells further enhance the proliferation, invasion and metastasis of A549 cells. Meanwhile, we performed transcriptome sequencing to explore the downstream genes of ANXA2 to screen potential targets for follow-up studies. Analysis based on public data showed that ANXA2 was related to the worse survival performance and clinical features of lung cancer. Gene set enrichment analysis based on the Hallmark gene set indicated that the patient with high ANXA2 expression might have a higher activity of the apical surface, reactive oxygen species pathway, angiogenesis, TGF-ß signaling, MYC target, but lower activity of pancreas-ß cells. More important, our results showed that ANXA2 can affects immunotherapy response and reshape immune microenvironment of lung cancer. Conclusions: This study demonstrates that ANXA2 activates CP-H122 cells, affects A549 cell behavior, and impacts lung cancer prognosis and immunotherapy response.

Effects of Z-VaD-Ala-Asp-Fluoromethyl Ketone (Z-VAD-FMK) and Acetyl-Asp-Glu-Val-Asp-Aldehyde(Ac-DEVD-CHO) on Inflammation and Mucus Secretion in Mice Exposed to Cigarette Smoke.

Background and Objectives: Smoking can lead to airway inflammation and mucus secretion through the nucleotide-binding domain-like receptor protein 3/caspase-1 pathway. In this study, z-VaD-Ala-Asp-fluoromethyl ketone(Z-VAD), a pan-caspase inhibitor, and acetyl-Asp-Glu-Val-Asp-aldehyde(Ac-DEVD), a caspase-3 inhibitor, were used to investigate the effect of caspase inhibitors on the expression of interleukin(IL)-1ß and IL-8, airway inflammation, and mucus secretion in mice exposed to cigarette smoke(CS). Methods: Thirty-two C57BL/6J male mice were divided into a control group, Smoke group, Z-VAD group, and Ac-DEVD group. Except for the control group, the animals were all exposed to CS for three months. After the experiment, lung function was measured and hematoxylin and eosin staining and periodic acid-Schiff staining were performed. The levels of IL-1ß, IL-8, and mucin 5ac(Muc5ac) in serum and bronchoalveolar lavage fluid(BALF) were determined by enzyme-linked immunosorbent assay. Results: Compared with the control group, the lung function of mice exposed to smoke was poorer, with a large number of inflammatory cells infiltrating around the airway, collapse of alveoli, expansion and fusion of distal alveoli, and formation of emphysema. The Z-VAD group was relieved compared with the smoke group. Airway inflammation was also reduced in the Ac-DEVD group compared with the Smoke group, but the degree of emphysema was not significantly improved. Although Z-VAD relieved airway inflammation and emphysema, Ac-DEVD only relieved inflammation. Z-VAD and Ac-DEVD decreased serum IL-1ß and IL-8 levels. In BALF, IL-1ß was decreased in Z-VAD group and IL-8 was highest in Smoke +Ac-DEVD group compared with control group and Ac-DEVD group. There was no significant difference in the expression of Muc5ac in serum. However, in BALF, levels of Muc5ac were higher in the smoking group and the lowest in the Ac-DEVD group. Conclusion: Mice exposed to smoke had decreased lung function and significant cilia lodging, epithelial cell shedding, and inflammatory cell infiltration, with significant emphysema formation. The pan-caspase inhibitor, Z-VAD, improved airway inflammation and emphysema lesions in the mice exposed to smoke and reduced IL-1ß and IL-8 levels in serum. The caspase-3 inhibitor, Ac-DEVD, reduced airway inflammation, serum IL-1ß and IL-8 levels, and Muc5ac levels in BALF, but it did not improve emphysema.

The release of tryptase from mast cells promote tumor cell metastasis via exosomes.

BACKGROUND: Cancer cells release exosomes and can be taken up by mast cells (MCs), but the potential functional effects of MCs on tumor metastasis remain unknown. METHOD: Exosomes were isolated from the lung adenocarcinoma cell line A549, and the uptake of PKH26-labeled exosomes by bone marrow MCs was examined via flow cytometry and fluorescence microscopy. Cytokines and tryptase in MC supernatant were analyzed using an ELISA kit, and the presence of tryptase was evaluated by Western blotting. Cell proliferation and migration were determined through CCK-8 and transwell assays. Proteins in the tryptase-JAK-STAT signaling pathway were detected by Western blotting. RESULTS: In this study, we show that exosomes from A549 cells can be taken up by MCs. Moreover, A549 exosomes contain stem cell factor (SCF) to MCs and subsequently induce the activation of MCs through SCF-KIT signal transduction, which leads to MC degranulation and the release of tryptase. Tryptase accelerates the proliferation and migration of human umbilical vein endothelial cells (HUVECs) through the JAK-STAT signaling pathway. CONCLUSIONS: Our results reveal a mechanism for metastasis in which exosomes can transfer SCF to and activate MCs, which can affect the release of tryptase and the angiogenesis of HUVECs.