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OBJECTIVE: This investigation aims to explore the expression levels of serine protease 8 (PRSS8) in gefitinib-resistant Non-Small Cell Lung Cancer (NSCLC) cell lines (PC9/GR) and elucidate its mechanism of action. METHODOLOGY: We measured PRSS8 expression in gefitinib-resistant (PC9/GR) and sensitive (PC9) NSCLC cell lines using Western blot analysis. PRSS8-specific small interfering RNA (PRSS8-siRNA), a recombinant plasmid, and a corresponding blank control were transfected into PC9/GR cells. Subsequently, Western blot analyses were conducted to assess the expression levels of PRSS8, phosphorylated AKT (p-AKT), AKT, phosphorylated mTOR (p-mTOR), mTOR, and various apoptosis-related proteins within each group. Additionally, a cell proliferation assay utilizing Cell Counting Kit-8 (CCK8) was performed on each group treated with gefitinib. RESULT: PRSS8 expression was markedly higher in PC9/GR cells compared to PC9 cells (p < 0.05). The group treated with PRSS8-siRNA exhibited significantly reduced protein expression levels of PRSS8, p-AKT, p-mTOR, ß-catenin, and BCL-2 compared to the control siRNA (Con-siRNA) group, whereas expressions of Caspase9 and Bax were significantly increased. In the untransfected PC9/GR cells, protein expressions of PRSS8, p-AKT, pmTOR, and BCL-2 were significantly elevated when compared with the plasmid-transfected group, which also showed a significant reduction in Bax expression. The proliferative activity of the PRSS8-siRNA group postgefitinib treatment was significantly diminished at 24, 48, and 72 hours in comparison to the Con-siRNA group. CONCLUSION: The findings indicate that PRSS8 contributes to the acquisition of resistance to gefitinib in NSCLC, potentially through regulation of the AKT/mTOR signaling pathway.
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Drug resistance is a major cause of treatment failure and post-treatment disease progression in patients with cancer. This study aimed to investigate the mechanisms of chemoresistance to gemcitabine (GEM) plus cisplatin (cis-diamminedichloroplatinum, DDP) combination therapy in stage IV lung squamous cell carcinoma (LSCC). It also examined the functional role of lncRNA ASBEL and lncRNA Erbb4-IR in the malignant progression of LSCC. The expression of lncRNA ASBEL, lncRNA Erbb4-IR, miR-21, and LZTFL1 mRNA was examined in human stage IV LSCC tissues and adjacent normal tissues, human LSCC cells and normal human bronchial epithelial cells using qRT-PCR. Furthermore, LZTFL1 protein levels were also examined using western blots. Cell proliferation, cell migration and invasion, and cell cycle progression and apoptosis were evaluated in vitro using the CCK-8, transwell, and flow cytometry assays, respectively. Based on the treatment response, LSCC tissues were classified as GEM-, DDP-, and GEM+DDP-sensitive/resistant. The MTT assay was performed to assess the chemoresistance of human LSCC cells to GEM, DDP, and GEM+DDP following transfection experiments. The results showed that lncRNA ASBEL, lncRNA Erbb4-IR, and LZTFL1 were down-regulated in human LSCC tissues and cells, whereas miR-21 was up-regulated. In stage IV human LSCC tissues, miR-21 levels were negatively correlated with those of lncRNA ASBEL, lncRNA Erbb4-IR, and LZTFL1 mRNA. The overexpression of lncRNA ASBEL and lncRNA Erbb4-IR inhibited cell proliferation, migration, and invasion. It also blocked cell cycle entry and accelerated apoptosis. These effects were mediated by the miR-21/LZTFL1 axis and reduced chemoresistance to GEM+DDP combination therapy in stage IV human LSCC. These findings indicate that lncRNA ASBEL and lncRNA Erbb4-IR function as tumor suppressors in stage IV LSCC and attenuate chemoresistance to GEM+DDP combination therapy via the miR-21/LZTFL1 axis. Hence, lncRNA ASBEL, lncRNA Erbb4-IR, and LZTFL1 may be targeted to enhance the efficacy of GEM+DDP combination chemotherapy against LSCC.
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Background: This study aims to determine the regularity of sentinel lymph nodes of peripheral lung parenchyma and the lymphatic drainage between adjacent pulmonary segments in experimental animals. Methods: Thoracotomy was performed on 12 experimental Guizhou miniature pigs, and 1 mL methylene blue was injected into the superior segment of the lower lobe (S6) and the anterior segment of the upper lobe (S3), successively, to observe lymphatic drainage, in sentinel lymph nodes and the lymphatic drainage between adjacent segments. Results: A total of 161 lymphatic vessels were observed in 48 pulmonary segments, with an average of 3.4 lymphatic vessels per segment: RS6 (superficial 1.0±0.61, deep 2.5±1.00), RS3 (superficial 1.0±0.51, deep 2.0±1.07), LS6 (superficial 3.0±0.42, deep 1.0±0.38), LS3 (superficial 1.0±0.43, deep 2.0±0.62). There were significantly more lymphatic vessels in deep plexus than in superficial (p<0.01). As for sentinel lymph nodes, LS6 drained to the hilar, subcarinal and 4L lymph nodes; RS6 drained to the hilar and subcarinal lymph nodes; LS3 drained to the hilar and 4L lymph nodes; and RS3 drained to the hilar and 4R lymph nodes. In addition, methylene blue could drain from peripheral lung tissue of S3 and S6 directly to mediastinal lymph nodes through superficial plexuses. Lymphatic drainage regularity of S3 and S6 to adjacent pulmonary segments were also observed. The R6 rarely drained to the basal segment, while R3 could possibly drain to the posterior segment. Conclusion: The regularity of peripheral pulmonary parenchymal lymphatic drainage in experimental animals can provide a basis for the management of lymph nodes in pulmonary segmentectomy in humans, to a certain extent.
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BACKGROUND: Circular RNA hsa_circ_0003340 (circ-OGDH) has been uncovered to be involved in esophageal squamous cell carcinoma (ESCC) progression. However, the mechanism by which circ-OGDH regulates ESCC progression is unclear. METHODS: Expression levels of circ-OGDH, microRNA (miR)-615-5p, and PDX1 (pancreatic and duodenal homeobox 1) mRNA were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, apoptosis, migration, invasion, and cell cycle progression of ESCC cells were analyzed by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide), colony formation, flow cytometry, and transwell assays. Measurement of glutamine consumption, α-KG (α-ketoglutarate) production, and ATP (Adenosine Triphosphate) content using corresponding kits. Protein levels were analyzed by Western blotting. The targeting relationship between circ-OGDH or PDX1 and miR-615-5p was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The function of circ-OGDH in ESCC was confirmed by animal experiments. RESULTS: Circ-OGDH was upregulated in ESCC. Circ-OGDH inhibition reduced ESCC growth in vivo and accelerated cell apoptosis, cell cycle arrest, repressed cell proliferation, migration, invasion, and reduced cell glutamine metabolism in ESCC cells in vitro. MiR-615-5p was downregulated in ESCC, while PDX1 had an opposite result. Circ-OGDH sponged miR-615-5p to regulate PDX1 expression. MiR-615-5p inhibitor neutralized the repressive effect of circ-OGDH knockdown on malignancy and glutamine metabolism of ESCC cells. PDX1 overexpression counteracted the inhibitory impact of miR-615-5p mimic on malignancy and glutamine metabolism of ESCC cells. CONCLUSION: Circ-OGDH sponged miR-615-5p to elevate PDX1 expression, thus elevating glutamine metabolism and promoting tumor growth in ESCC. The study offered evidence to support circ-OGDH as a promising target for ESCC therapy.
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Lung cancer is a leading cause of cancer-associated mortality and morbidity worldwide. Previous studies have suggested that ATP-binding cassette transporter E1 (ABCE1) acetylation is upregulated in the tissues and cells of lung cancer and is associated with the prognosis of patients with lung cancer. The aim of the present study was to investigate the association between Tat interactive protein 60 kDa (Tip60) expression and ABCE1 acetylation, and the effect of Tip60 on the biological functions of A549 lung carcinoma cells. The expression levels of Tip60 and ABCE1 acetylation were examined using western blot and co-immunoprecipitation (Co-IP) assays in normal bronchial epithelial (HBE) and human lung cancer (A549) cells. The expression of Tip60 then was downregulated in A549 cells using small interfering RNA. Wound healing and Transwell assays were used to assess cell invasion and migration. The biological effects of Tip60 in lung cancer cells were investigated using MTT and flow cytometric assays. Subsequently, tumor xenografts were established to observe the effect of Tip60 on lung cancer in vivo. Western blot and Co-IP assays were performed to investigate the mechanism of Tip60 in A549 cells. Tip60 expression and ABCE1 acetylation were upregulated in the lung cancer cells compared with the normal bronchial epithelial cells. Downregulation of Tip60 decreased the acetylation of ABCE1 and inhibited cell proliferation, invasion and migration. Furthermore, the downregulation of Tip60 activated the apoptotic pathway in order to achieve its suppressive function. In the xenografts, the tumor weight and volume were notably reduced due to the downregulation of Tip60 expression. The results of the present study strongly suggest that Tip60 is a novel target in the prevention and treatment of lung cancer.