Correlation study of biological characteristics of non-small cell lung cancer A549 cells after transfecting plasmid by microbubble ultrasound contrast agent

Ultrasound microbubbles-mediated miR-216b affects MALAT1-miRNA axis in non-small cell lung cancer cells

MiR-216b is ectopically expressed in various cancers. Ultrasound microbubbles (UTMBs) are an effective method for miRNA delivery. This article mainly explored the involvement of lncRNA in the effects of UTMBs-mediated miR-216b on non-small cell lung cancer (NSCLC) progression. Expressions and relationship of miR-216b and MALAT1 were examined using quantitative real-time polymerase chain reaction (qRT-PCR), Pearson, TargetScan, and dual-luciferase reporter assay. After the transfection with liposome- or UTMBs-mediated miR-216b mimic (M) or MALAT1 overexpression plasmid alone or together, levels of miR-216b and MALAT1, cell biological behaviors, as well as expressions of apoptosis- and epithelial mesenchymal transition (EMT)-related markers were examined using qRT-PCR, cell functional experiments, and western blot. Besides, we used qRT-PCR to quantify the expressions of multiple downstream miRNAs of MALAT1. MiR-216b expression was weakened yet MALAT1 expression was enhanced in NSCLC tissues, and miR-216b was negatively bound to MALAT1. TargetScan analysis manifested that miR-216b, targeted by MALAT1, was down-regulated in NSCLC cells. UTMBs-mediated miR-216b M further intensified miR-216b level yet weakened cell biological behaviors. The inhibitory effect of UTMBs-mediated miR-216b M on cell biological behaviors and MALAT1 expression was greatly better relative to that of miR-216b M. Moreover, miR-216b restrained the cell biological behaviors by repressing MALAT1 expression. We further manifested that miR-216b facilitated the expressions of apoptosis-related markers, but restrained those of EMT-related markers by repressing MALAT1 expression. Moreover, UTMBs-mediated miR-216b M enhanced the expressions of downstream multiple miRNAs of MALAT1, but this tendency was reversed by co-transfection of overexpressed MALAT1 and miR-216b M. Collectively, UTMBs-mediated miR-216b M restrained NSCLC cell growth by modulating the MALAT1-miRNA axis.

Inter-laboratory variability of A549 epithelial cells grown under submerged and air-liquid interface conditions

In vitro cell models offer a unique opportunity for conducting toxicology research, and the human lung adenocarcinoma cell line A549 is commonly used for toxicology testing strategies. It is essential to determine whether the response of these cells grown in different laboratories is consistent. In this study, A549 cells were grown under both submerged and air-liquid interface (ALI) conditions following an identical cell seeding protocol in two independent laboratories. The cells were switched to the ALI after four days of submerged growth, and their behaviour was compared to submerged conditions. The membrane integrity, cell viability, morphology, and (pro-)inflammatory response upon positive control stimuli were assessed at days 3, 5, and 7 under submerged conditions and at days 5, 7, and 10 at the ALI. Due to the high variability of the results between the two laboratories, the experiment was subsequently repeated using identical reagents at one specific time point and condition (day 5 at the ALI). Despite some variability, the results were more comparable, proving that the original protocol necessitated improvements. In conclusion, the use of detailed protocols and consumables from the same providers, special training of personnel for cell handling, and endpoint analysis are critical to obtain reproducible results across independent laboratories.

Ultrasound-microbubbles-mediated microRNA-449a inhibits lung cancer cell growth via the regulation of Notch1

Background

The application of gene-loaded microbubbles (MBs) combined with ultrasound that results in increased delivery efficiency may be an excellent method of gene delivery. This study aimed to discuss the effects of ultrasound-MB-mediated microRNA (miR)-449a on lung cancer (LC) development by targeting Notch1.

Methods

Initially, miR-449a expression in LC tissues, paracancerous tissues, LC cell lines, and lung epithelial cells was detected and its association with LC patients’ clinical characteristics was analyzed. The gain-of-function studies were performed to probe the roles of miR-449a and ultrasound-MB-mediated miR-449a in LC progression. Then, RT-qPCR combined with Western blot analysis was applied to verify the levels of miR-449a, Notch1, proliferation- and apoptosis-related proteins. Moreover, xenograft tumors in nude mice were also applied for in vivo experiments.

Results

Poorly expressed miR-449a was observed in LC, and its expression was associated with clinical staging, differentiation and lymph node metastasis of LC patients. Overexpression of miR-449a suppressed LC cell proliferation and promoted G2/M arrest and apoptosis. Ultrasound-MB-mediated miR-449a strengthened inhibitory effects of miR-449a on cell growth and resistance to apoptosis. miR-449a inhibited H1299 cell activity by targeting Notch1.

Conclusion

Our data supported that miR-449a overexpression inhibited LC cell growth, and ultrasound-MB-mediated miR-449a reinforced the repressive effects of miR-449a on LC progression. This investigation may offer new insight for LC treatment.