miR-324-3p reverses cisplatin resistance by inducing GPX4-mediated ferroptosis in lung adenocarcinoma cell line A549.

PURPOSE: MicroRNAs act as crucial regulators of a diverse range of biological processes, including chemoresistance. Our study aimed to investigate the effect of miR-324-3p on lung adenocarcinoma cell line A549 resistant to cis-diamminedichloroplatinum II (DDP, aka cisplatin). METHODS: The miR-324-3p expression levels in cisplatin-sensitive A549（A549） and cisplatin-resistant A549 (A549/DDP) cells were determined by qRT-PCR assay. Cell proliferation was determined with the commercial kit CCK-8 and colony formation assay, whereas cell death was analyzed using flow cytometry. The target gene of miR-324-3p was identified and validated with the luciferase reporter and western blot assays. The role of miR-324-3p in modulating cisplatin resistance was evaluated in vitro. RESULTS: The expression of miR-324-3p was found to be significantly downregulated in the A549/DDP cells. Conversely, miR-324-3p overexpression reversed cisplatin resistance in the cells. With regard to the possible mechanism underlying this phenomenon, we identified the glutathione peroxidase 4 (GPX4) gene as the direct target of miR-324-3p, where overexpression of the gene reversed the miR-324-3p effect of sensitizing the A549/DDP cells to cisplatin. Furthermore, the GPX4 inhibitor RSL3 could mimic the effect of miR-324-3p upregulation in increasing the sensitivity of the cisplatin-resistant cells to the drug. Significantly, miR-324-3p enhanced cisplatin-induced ferroptosis in the A549/DDP cells. CONCLUSION: Our findings revealed the role of the miR-324-3p-GPX4 signaling axis in A549/DDP cells and how the targeting of this axis could be a potential strategy for reversing cisplatin resistance in human non small cell lung cancer (NSCLC).

Fungal Immunomodulatory Protein from Nectria haematococca Suppresses Growth of Human Lung Adenocarcinoma by Inhibiting the PI3K/Akt Pathway.

Lung cancer is a common disease that is associated with poor prognosis. Fungal immunomodulatory protein from Nectria haematococca (FIP-nha) has potential as a lung cancer therapeutic; as such, illuminating its anti-tumor mechanism is expected to facilitate novel treatment options. Here, we showed that FIP-nha affects lung adenocarcinoma growth ex vivo and in vivo. Comparative quantitative proteomics showed that FIP-nha negatively regulates PI3K/Akt signaling and induces cell cycle arrest, autophagy, and apoptosis. We further demonstrated that FIP-nha suppresses Akt phosphorylation, leading to upregulation of p21 and p27 and downregulation of cyclin B1, cyclin D1, CDK2, and CDK4 expression, ultimately resulting in G1/S and G2/M cell cycle arrest. Meanwhile, FIP-nha-induced PI3K/Akt downregulation promotes A549 apoptosis by increasing the expression ratio of Bax/Bcl-2 and c-PARP and autophagy by decreasing the phosphorylation of mTOR. Thus, we comprehensively revealed the anti-tumor mechanism of FIP-nha, which inhibits tumor growth by modulating PI3K/Akt-regulated cell cycle arrest, autophagy, and apoptosis, and provided the basis for further application of fungal immunomodulatory proteins, especially FIP-nha.

Ultrastructural changes associated to the neuroendocrine transdifferentiation of the lung adenocarcinoma cell line A549.

The neuroendocrine transdifferentiation has been found in many cancer cell types, such as prostate, lung and gastrointestinal cells and is accompanied by a lower patient life expectancy. The transdifferentiation process has been induced in vitro by the exposure to different stimuli in human lung adenocarcinoma. The aim of this work was to identify the morphological characteristics of the neuroendocrine phenotype in a human lung cancer cell line, induced by two cAMP elevating agents (IBMX and FSK). Our results showed two phenotypes, one produced by IBMX with higher volume, cell size and increased number of secondary projections, and the other produced by FSK with higher area, roughness of the membrane, cell neurite percentage, number of outgrowths per cell and increased number of primary projections. In conclusion, we describe some morphological and ultrastructural characteristics of the neuroendocrine phenotype in A549 human lung cancer cell line promoted by IBMX and FSK to contribute to the understanding of the autocrine or paracrine signaling within the tumor microenvironment.

The Prevalence of the EML4-ALK Fusion Gene in Cytology Specimens from Patients with Lung Adenocarcinoma.

BACKGROUND: Under the National Comprehensive Cancer Network (NCCN) guidelines for non-small-cell lung carcinoma (NSCLC), anaplastic lymphoma kinase (ALK) gene rearrangement is required to be assessed. However, data showing the prevalence of the ALK rearrangement is still deficient and is not yet available in Indonesia. This study used direct smear preparation from transthoracic needle specimens that are minimally invasive. The main objective of the study is to identify the prevalence of the ALK fusion rearrangement gene in cytological specimens. MATERIALS AND METHODS: A total of 35 direct smear preparations diagnosed as lung adenocarcinoma and EGFR mutation negative were involved in this study. The samples were taken between 2017 and 2019. These samples were examined for EML4-ALK fusion rearrangement gene using qRT-PCR. The EML4-ALK rearrangement status was determined by qRT-PCR with high-resolution melting (HRM) analysis. RESULTS: A total of 28 (80%) samples were from males, and 7 samples were from females. Seven (20% 95% CI: 8.4%-36.9%) samples were EML4-ALK rearrangement positive. The average age of the patients was 63.5 years old. The most common sites of metastasis in this study were pleural cavity, bone, liver, and CNS. CONCLUSIONS: qRT-PCR successfully identified EML4-ALK fusion rearrangement in direct smear preparations of lung adenocarcinoma. Direct smear samples can be used for EML4-ALK rearrangement detection using qRT-PCR. The EML4-ALK rearrangement gene has high prevalence in selected lung adenocarcinoma and EGFR mutation-negative populations. ALK inhibitors in lung cancer can be openly considered for use in Indonesian patients to improve the outcome of this subset of patients.

HMGA2 regulates circular RNA ASPH to promote tumor growth in lung adenocarcinoma.

In this study, we identified a circular form of ASPH RNA (circASPH), expression of which was upregulated in lung adenocarcinoma and the human lung adenocarcinoma cell lines. We also found a positive correlation between circASPH level and the T and N stages of lung adenocarcinoma patients. Patients with higher levels of circASPH had a shorter overall survival. Moreover, we demonstrated that circASPH was directly regulated by HMGA2 and Twist1. The direct positive regulation of circASPH by Twist1 was dependent on the presence of HMGA2. Functional assays indicated that circASPH promoted the proliferation, migration, and invasion of lung adenocarcinoma cell lines in vitro. The promoting effect of tumor growth by circASPH was also observed in vivo. Mechanistically, circASPH was identified to act as a molecular sponge for miR-370 and abrogate miR-370-mediated inhibition of HMGA2. Finally, we demonstrated that the oncogenic function of circASPH was HMGA2-dependent. These findings reveal the oncogenic functions of the HMGA2-circASPH-HMGA2 axis and may be useful in developing circRNA-based therapeutic strategies for lung adenocarcinoma.