sphingosine-kinase and Adenocarcinoma-of-Lung

Lung adenocarcinoma (LUAD) is a fatal threat to human health, while the mechanism remains unclear, and the therapy brings limited therapeutic effects. Transcription factor Homeobox C11 (HOXC11) was previously proved to be related to hind limbs and metanephric development during the embryonic phase, and its role in tumors has been gradually recognized. Our study found that HOXC11 overexpressed in LUAD and was associated with worse overall survival. Moreover, its expression in lung cancer was regulated by IκB kinase α (IKKα), a pivotal kinase in NF-κB signaling, which was related to the ubiquitination of HOXC11. We further proved that HOXC11 could enhance the ability of proliferation, migration, invasion, colony formation, and the progression of the cell cycle in LUAD cells. Meanwhile, it also accelerated the formation of subcutaneous and lung metastases tumors. In contrast, loss of HOXC11 in LUAD cells significantly inhibited these malignant phenotypes. At the same time, HOXC11 regulated the expression of sphingosine kinase 1 (SPHK1) by directly binding to its promoter region. Therefore, we conclude that HOXC11 impacts the development of LUAD and facilitates lung cancer progression by promoting the expression of SPHK1.

Topics: Adenocarcinoma of Lung; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; Homeodomain Proteins; Humans; Lung Neoplasms; Phosphotransferases (Alcohol Group Acceptor)

Lung adenocarcinoma (LUAD) has high morbidity and is prone to recurrence. TIMELESS (TIM), which regulates circadian rhythms in Drosophila, is highly expressed in various tumors. Its role in LUAD has gained attention, but the detailed function and mechanism have not been clarified completely at present.. Tumor samples from patients with LUAD patient data from public databases were used to confirm the relationship of TIM expression with lung cancer. LUAD cell lines were used and siRNA of TIM was adopted to knock down TIM expression in LUAD cells, and further cell proliferation, migration and colony formation were analyzed. By using Western blot and qPCR, we detected the influence of TIM on epidermal growth factor receptor (EGFR), sphingosine kinase 1 (SPHK1) and AMP-activated protein kinase (AMPK). With proteomics analysis, we comprehensively inspected the different changed proteins influenced by TIM and did global bioinformatic analysis.. We found that TIM expression was elevated in LUAD and that this high expression was positively correlated with more advanced tumor pathological stages and shorter overall and disease-free survival. TIM knockdown inhibited EGFR activation and also AKT/mTOR phosphorylation. We also clarified that TIM regulated the activation of SPHK1 in LUAD cells. And with SPHK1 siRNA to knock down the expression level of SPHK1, we found that EGFR activation were inhibited greatly too. Quantitative proteomics techniques combined with bioinformatics analysis clarified the global molecular mechanisms regulated by TIM in LUAD. The results of proteomics suggested that mitochondrial translation elongation and termination were altered, which were closely related to the process of mitochondrial oxidative phosphorylation. We further confirmed that TIM knockdown reduced ATP content and promoted AMPK activation in LUAD cells.. Our study revealed that siTIM could inhibit EGFR activation through activating AMPK and inhibiting SPHK1 expression, as well as influencing mitochondrial function and altering the ATP level; TIM's high expression in LUAD is an important factor and a potential key target in LUAD.

Topics: Adenocarcinoma of Lung; Adenosine Triphosphate; AMP-Activated Protein Kinases; Cell Line, Tumor; Cell Movement; Cell Proliferation; ErbB Receptors; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; RNA, Small Interfering

Long non-coding RNAs (lncRNAs) are closely associated with the development of lung adenocarcinoma (LADC). The present study focused on the role of LINC00960 in LADC. miRNA and mRNA expression levels were detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Cellular functions were evaluated by MTT, colony formation, and Transwell assays, respectively. LINC00960 Luciferase and RNA pull-down assays were performed to clarify the interaction between miR-124a and LINC00960 or Recombinant Sphingosine Kinase 1 (SphK1). We observed that LINC00960 was overexpressed in LADC tumor tissues and cell lines. LINC00960 knockdown suppressed the proliferation, migration, and invasion of LADC cells. Moreover, LINC00960 sponged miR-124a to inhibit the SphK1/S1P pathway in LADC cells. LINC00960 knockdown markedly reduced the rate of tumor growth. The luciferase reporter assay results demonstrated an interaction between miR-124a and LINC00960 or SphK1. This interaction was confirmed using the RNA pull-down assay. In addition, miR-124a downregulation or SphK1 upregulation reversed the inhibitory effects of LINC00960 knockdown on cellular functions of LADC cells, suggesting that LINC00960 may be a potential therapeutic biomarker for LADC via the miR-124a/SphK1 axis. Accordingly, LINC00960 may be a potential therapeutic biomarker for LADC.

Topics: A549 Cells; Adenocarcinoma of Lung; Animals; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Lung Neoplasms; Male; Mice; MicroRNAs; Neoplasm Metastasis; Neoplasm Transplantation; Phosphotransferases (Alcohol Group Acceptor); RNA, Long Noncoding; Up-Regulation

The pleiotropic lipid mediator sphingosine-1-phosphate (S1P) exerts a multitude of effects on respiratory cell physiology and pathology through five S1P receptors (S1PR1-5). Epidemiological studies proved high levels of circulating S1P in non-small cell lung cancer (NSCLC) patients. Studies in literature suggest that high levels of S1P support carcinogenesis but the exact mechanism is still elusive. The aim of this study was to understand the mechanism/s underlying S1P-mediated lung tumor cell proliferation.. We used human samples of NSCLC, a mouse model of first-hand smoking and of Benzo(a)pyrene (BaP)-induced tumor-bearing mice and A549 lung adenocarcinoma cells.. We found that the expression of S1PR3 was also into the nucleus of lung cells in vitro, data that were confirmed in lung tissues of NSCLC patients, smoking and tumor bearing BaP-exposed mice. The intranuclear, but not the membrane, localization of S1PR3 was associated to S1P-mediated proliferation of lung adenocarcinoma cells. Indeed, the inhibition of the membrane S1PR3 did not alter tumor cell proliferation after Toll Like Receptor (TLR) 9 activation. Instead, according to the nuclear localization of sphingosine kinase (SPHK) II, the inhibition of the kinase completely blocked the endogenous S1P-induced tumor cell proliferation.. These results prove that the nuclear S1PR3/SPHK II axis is involved in lung tumor cell proliferation, highlighting a novel molecular mechanism which could provide differential therapeutic approaches especially in non-responsive lung cancer patients.

Topics: A549 Cells; Adenocarcinoma of Lung; Animals; Humans; Lung Neoplasms; Mice; Neoplasm Proteins; Phosphotransferases (Alcohol Group Acceptor); Signal Transduction; Sphingosine-1-Phosphate Receptors

Lung cancer is one of the most common and lethal types of oncological diseases. Despite the advanced therapeutic approaches, the prognosis for lung cancer still remains poor. Apparently, there is an imperative need for more efficient therapeutic strategies. In this work we report that concurrent treatment of human adenocarcinoma A549 cells with specific concentrations of two antitumor agents, the sphingosine kinase 1 inhibitor N, N dimethylsphingosine (DMS) and the alkylphosphocholine miltefosine, induced synergistic cytotoxic effect, which was confirmed by calculation of the combination index. The simultaneous action of these agents, induced significant decrease of A549 cell number, as well as pronounced morphological alterations. Combined drugs caused substantial apoptotic events, and significant reduction of the pro-survival marker sphingosine- 1-phosphate (S1P), when compared to the individual treatments with each of the anticancer drugs alone. Miltefosine is known to affect the synthesis of choline-containing phospholipids, including sphingomyelin, but we report for the first time that it also reduces S1P. Here we suggest a putative mechanism underlying the effect of miltefosine on sphingosine kinase 1, involving miltefosine-induced inhibition of protein kinase C. In conclusion, our findings provide a possibility for treatment of lung cancer cells with lower concentrations of the two antitumor drugs, DMS and miltefosine, which is favorable, regarding their potential cytotoxicity to normal cells.

Topics: A549 Cells; Adenocarcinoma of Lung; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Drug Synergism; Humans; Lysophospholipids; Phosphorylcholine; Phosphotransferases (Alcohol Group Acceptor); Protein Kinase Inhibitors; Sphingosine