Establishment of an orthotopic model of lung cancer by transthoracic lung puncture using tumor fragments.

Background: Orthotopic models of lung cancer have been widely utilized, and the purpose of this study was to demonstrate the viability of our proposed modified modeling approach. Methods: A total of 50 female BALB/c mice were implanted with 1×1×1 mm fragments of a tumor sample into the left lung lobe. After 2 months of observation, the mice were humanely euthanized through CO2 inhalation. The macroscopic specimens were photographed, and the most representative neoplastic lesions were collected for histological analysis. Small-animal positron emission tomography/computed tomography (PET/CT) scans were conducted on 6 randomly selected mice. Results: Local tumor formation, ipsilateral thoracic tissue infiltration, the contralateral chest wall, right lung metastases, and distant kidney metastases were observed in these models. Overall, the tumor development and metastasis rates were 60.86% (28/46) and 57.14% (16/28), respectively. The 3 mice that had a small-animal PET/CT scan developed a local tumor, but no distant metastases were observed. Conclusions: This modified method was deemed reliable, reproducible, minimally invasive, straightforward, and comprehensible; it might serve as the foundation for developing patient-derived orthotopic xenografts of lung cancer.

microRNA-145 Inhibition Upregulates SIRT1 and Attenuates Autophagy in a Mouse Model of Lung Ischemia/Reperfusion Injury via NF-κB-dependent Beclin 1.

BACKGROUND: MicroRNA-145 (miR-145) has been shown to play a critical role in ischemia/reperfusion (I/R) injury; however, the expression and function of miR-145 in lung I/R injury have not been reported yet. This study aimed to elucidate the potential effects of miR-145 in lung I/R injury. METHODS: Lung I/R mice models and hypoxia/reoxygenation (H/R) pulmonary microvascular endothelial cell models were established. The expression of miR-145 and sirtuin 1 (SIRT1) was measured with reverse transcription-quantitative polymerase chain reaction and Western blot analysis in mouse lung tissue and cells. Artificial modulation of miR-145 and SIRT1 (downregulation) was done in I/R mice and H/R cells. Additionally, Pao2/FiO2 ratio, wet weight-to-dry weight ratio, and cell apoptosis in mouse lung tissues were determined by blood gas analyzer, electronic balance, and deoxyuridine triphosphate-biotin nick end-labeling assay, respectively. Autophagy marker Beclin 1 and LC3 expression, NF-κB acetylation levels, and autophagy bodies were detected in cell H/R and mouse I/R models by Western blot analysis. pulmonary microvascular endothelial cell apoptosis was detected with flow cytometry. RESULTS: miR-145 was abundantly expressed in the lung tissue of mice and PMVECs following I/R injury. In addition, miR-145 directly targeted SIRT1, which led to significantly decreased Pao2/FiO2 ratio and increased wet weight-to-dry weight ratio, elevated acetylation levels and transcriptional activity of NF-κB, upregulated expressions of tumor necrosis factor-α, interleukins-6, and Beclin 1, autophagy bodies, cell apoptosis, as well as LC3-II/LC3I ratio. CONCLUSIONS: In summary, miR-145 enhances autophagy and aggravates lung I/R injury by promoting NF-κB transcriptional activity via SIRT1 expression.