[Advances in hypoxia microenvironment and chemotherapy-resistant of lung cancer]

Doxorubicin-Loaded MnO2@Zeolitic Imidazolate Framework-8 Nanoparticles as a Chemophotothermal System for Lung Cancer Therapy

Doxorubicin-loaded MnO₂@zeolitic imidazolate framework-8 (DOX/MnO₂@ZIF-8) nanoparticles, a smart multifunctional therapeutic platform, were prepared for the treatment of lung cancer. The morphology, structure, and redox and photothermal properties of MnO₂@ZIF-8 were characterized by the corresponding methods. The anticancer drug DOX released from the DOX/MnO₂@ZIF-8 nanoparticles was measured. The cell viability of Lewis lung cancer (LLC) cells treated with MnO₂@ZIF-8 or DOX/MnO₂@ZIF-8 nanoparticles was determined using the cell counting kit-8 (CCK-8) method. The cellular uptake of DOX/MnO₂@ZIF-8 nanoparticles into LLC cells was observed using a confocal laser scanning microscope. TUNEL staining was performed to evaluate the in vivo therapeutic efficacy of DOX/MnO₂@ZIF-8 nanoparticles. The results showed that the as-prepared MnO₂@ZIF-8 nanoparticles had an average particle size of 155.59 ± 13.61 nm and the DOX loading efficiency was 12 wt %. MnO₂@ZIF-8 could react with H₂O₂ to generate O₂ and showed a great photothermal conversion effect both in vitro and in vivo. Up to 82% of total DOX could be released from DOX/MnO₂@ZIF-8 nanoparticles at pH = 5.0. The CCK-8 assay showed that MnO₂@ZIF-8 had low cytotoxicity to LLC cells, while DOX/MnO₂@ZIF-8 can significantly reduce the cell viability. DOX/MnO₂@ZIF-8 can be accumulated in LLC cells over time. Compared with PBS and DOX/MnO₂@ZIF-8 groups, the mice in the DOX/MnO₂@ZIF-8 + NIR group had the most apoptotic cells and significantly reduced tumor volume. In conclusion, these findings suggest that the as-prepared MnO₂@ZIF-8 nanoparticles with synergetic therapeutic effects by photothermal therapy and improved tumor microenvironment and as a pH-responsive nanocarrier for delivering the nonspecific anticancer drug DOX might be applied in the treatment of lung cancer.

High Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Expression Promotes Proliferation, Migration, and Invasion of Non-Small Cell Lung Cancer via ERK/Mitogen-Activated Protein Kinase (MAPK) Signaling Pathway

Background

In present study, we explored the function of the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) gene in the development of non-small cell lung cancer (NSCLC).

Material/Methods

qRT-PCR was used to detect the MALAT1 mRNA expression level in cancer tissues and adjacent normal tissues of 115 NSCLC patients and in cell lines. MALAT1-mimic, MALAT1-inhibitor, and corresponding negative controls (NC) were utilized to transfect the H460 cells. Proliferation, migration, and invasion of H460 cells were evaluated by MTT method and Transwell assay. Expression levels of proteins in the ERK/MAPK signaling pathway were assessed by Western blot analysis.

Results

MALAT1 mRNA was upregulated in NSCLC tissues and cell lines compared to that in adjacent tissues and normal human bronchial cell line (BEAS-2B), respectively. Overexpression of MALAT1 significantly strengthened the proliferation, migration, and invasion ability of H460 cells. In comparison with the NC group, expression levels of CXCL5 and p-JNK proteins were elevated, while p-MAPK and p-ERK proteins were decreased in the MALAT1-mimic group. MALAT1 targets the 3′-untranslated region (UTR) fragment of the CXCL5 gene and inhibits its translation. Disturbance of the CXCL5 gene can reduce the protein expression of MAPK, p-MEK1/2, p-ERK1/2, and p-JNK, and inhibit the proliferation, migration, and invasion of MALAT1-mimic cells.

Conclusions

High MALAT1 expression promotes the proliferation, migration, and invasion of non-small cell lung cancer via the ERK/MAPK signaling pathway.

Highly sensitive electron paramagnetic resonance nanoradicals for quantitative intracellular tumor oxymetric images

Purpose: Tumor oxygenation is a critical parameter influencing the efficacy of cancer therapy. Low levels of oxygen in solid tumor have been recognized as an indicator of malignant progression and metastasis, as well as poor response to chemo- and radiation therapy. Being able to measure oxygenation for an individual's tumor would provide doctors with a valuable way of identifying optimal treatments for patients. Methods: Electron paramagnetic resonance imaging (EPRI) in combination with an oxygen-measuring paramagnetic probe was performed to measure tumor oxygenation in vivo. Triarylmethyl (trityl) radical exhibits high specificity, sensitivity, and resolution for quantitative measurement of O₂ concentration. However, its in vivo applications in previous studies have been limited by the required high dosage, its short half-life, and poor intracellular permeability. To address these limitations, we developed high-capacity nanoformulated radicals that employed fluorescein isothiocyanate-labeled mesoporous silica nanoparticles (FMSNs) as trityl radical carriers. The high surface area nanostructure and easy surface modification of physiochemical properties of FMSNs enable efficient targeted delivery of highly concentrated, nonself-quenched trityl radicals, protected from environmental degradation and dilution. Results: We successfully designed and synthesized a tumor-targeted nanoplatform as a carrier for trityl. In addition, the nanoformulated trityl does not affect oxygen-sensing capacity by a self-relaxation or broadening effect. The FMSN-trityl exhibited high sensitivity/response to oxygen in the partial oxygen pressure range from 0 to 155 mmHg. Furthermore, MSN-trityl displayed outstanding intracellular oxygen mapping in both in vitro and in vivo animal studies. Conclusion: The highly sensitive nanoformulated trityl spin probe can profile intracellular oxygen distributions of tumor in a real-time and quantitative manner using in vivo EPRI.