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Prostaglandin E2 (PGE2), which is a potent pro-inflammatory lipid mediator, is biosynthesized from arachidonic acid by cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES-1). Non-steroidal anti-inflammatory drugs (NSAIDs) are used clinically as COX inhibitors, but they have gastrointestinal and cardiovascular side-effects. Thus, the terminal enzyme mPGES-1 holds promise as the next therapeutic target. In this study, we found that the ellagitannins granatin A and granatin B isolated from pomegranate leaves, and geraniin, which is their structural analog, selectively suppressed mPGES-1 expression without affecting COX-2 in non-small cell lung carcinoma A549 cells. The ellagitannins also down-regulated tumor necrosis factor α, inducible nitric oxide synthase, and anti-apoptotic factor B-cell chronic lymphocytic leukemia/lymphoma 2, and induced A549 cells to undergo apoptosis. These findings indicate that the ellagitannins have anti-inflammatory and anti-carcinogenic effects, due to their specific suppression of mPGES-1. Abbreviations: Bcl-2: B-cell chronic lymphocytic leukemia/lymphoma 2; COX: cyclooxygenase; CRE: cAMP response element; DHHDP: dehydrohexahydroxydiphenoyl; Et2O: diethyl ether; EtOAc: ethyl acetate; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; iNOS: inducible nitric oxide synthase; mPGES-1: microsomal prostaglandin E synthase-1; n-BuOH: water-saturated n-butanol; NSAIDs: non-steroidal anti-inflammatory drugs; NF-κB: nuclear factor-κB; PG: prostaglandin; TNF: tumor necrosis factor; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling Ellagitannins from pomegranate leaves suppressed mPGES-1 expression without affecting COX-2, and showed anti-inflammatory and anti-carcinogenic effects. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the role of phosphatidylinositol-3-kinase protein kinase B (PI3K/Akt) signaling pathway in the apoptosis of H1299 lung cancer cells induced by epigallocatechin gallate (EGCG). MATERIALS AND METHODS: H1299 lung cancer cells were treated with EGCG at a dose of 10 μM, 20 μM, and 40 μM, respectively. Cell culture was performed for 72 h and then: 1, cell proliferation was detected by MTT assay; 2, cell apoptosis rate was detected by flow cytometry; 3, expression of Caspase-3, Bax, and Bcl-2 was detected by Western blot; 4, expression of PI3K, p-PI3K, Akt, and p-Akt was detected by Western blot. RESULTS: The proliferation of H1299 cells was significantly inhibited 72 h after treatment with different doses of EGCG, and cell apoptosis rate was significantly increased (p<0.05). Compared with those in the control group, expression of PI3K and Akt in the lung cancer cells H1299 after EGCG treatment showed no significant differences (p>0.05), while expression levels of p-PI3K and p-Akt were significantly reduced (p<0.05). CONCLUSIONS: EGCG can inhibit the proliferation and induce apoptosis of H1299 lung cancer cells, and the effect is related to the inhibition of the activation of PI3K/Akt signaling pathway. [ABSTRACT FROM AUTHOR]

BACKGROUND: Despite improvements in medical technology, lung cancer metastasis remains a global health problem. The effects of microgravity on cell morphology, structure, functions, and their mechanisms have been widely studied; however, the biological effects of simulated microgravity on the interaction between cells and its eventual influence on the characteristics of cancer cells are yet to be discovered. We examined the effects of simulated microgravity on the metastatic ability of different lung cancer cells using a random positioning machine. METHODS: Human lung cancer cell lines of adenocarcinoma (A549) and squamous cell carcinoma (HI 703) were cultured in a 3D clinostat system which was continuously rotated at 5 rpm for 36 h. The experimental and control group were cultured under identical conditions with the exception of clinorotation. RESULTS: Simulated microgravity had different effects on each lung cancer cell line. In A549 cells, the proliferation rate of the clinostat group (2.267 ± 0.010) after exposure to microgravity did not differ from that of the control group (2.271 ± 0.020). However, in HI 703 cells, the proliferation rates of the clinostat group (0.534 ± 0.021) was lower than that of the control group (1.082 ± 0.021). The migratory ability of both A549 [remnant cell-free area: 33% (clinostat) vs. 78% (control)] and H1703 cells [40% (clinostat) vs. 68% (control)] were increased after exposure to microgravity. The results of the molecular changes in biomarkers after exposure to microgravity are preliminary. DISCUSSION: Simulated microgravity had different effects on the proliferation and migration of different lung cancer cell lines. [ABSTRACT FROM AUTHOR]

Sesamol has moved into biomedical research in recent years. However, its interactions with blood proteins and cancer cells have not been fully explored. Therefore, we aimed to investigate the interaction of sesamol with human serum albumin (HSA), A549 human nonsmall cell lung cancer (NSCLC) cell line, and Raw 264.7 macrophage. The interaction of HSA with sesamol was explored via application of fluorescence and circular dichroism (CD) spectroscopy studies as well as molecular docking analysis. Then, the cytotoxic effects of sesamol on A549 lung cancer cells and Raw 264.7 macrophages were evaluated by qPCR analysis. It was found that sesamol spontaneously (ΔG˚=-45.89 kJ/mol) binds with HSA having a high affinity (log K b = 8.05, n = 1.70, T = 298 K) and form a static complex trough contribution of hydrogen bonds and van der Waals interactions (ΔH˚=-409.43 kJ/mol, TΔS˚=-363.54 kJ/mol) which was supported by molecular docking study. Furthermore, by using CD and synchronous fluorescence spectroscopy analyses it was found that sesamol induced some minor secondary and tertiary structural changes, respectively in HSA structure. Cellular assays displayed that sesamol triggered selective cytotoxicity against A549 lung cancer cells through regulation of intrinsic apoptosis pathway mediated by mitigation of mitochondrial membrane potential, elevation of ROS generation, downregulation of Bax, and up regulation of caspase-9, −3. In conclusion, it was found that sesamol could show high affinity with HSA and mediate intrinsic apoptosis pathway through ROS generation in the A549 lung cancer cell lines. These data indicate that the biochemical and anticancer mechanisms of sesamol can be further investigated in future studies to integrate it in the biomedical platforms. [ABSTRACT FROM AUTHOR]

Abstract: Programmed cell death 4 (Pdcd4) tumor suppressor is frequently lost in tumors of various origins including lung cancer, and its loss contributes to tumor progression. However molecular mechanisms underlying Pdcd4 suppression in lung cancer cells remain largely unexplored. Here we investigated molecular mechanisms of Pdcd4 suppression in lung cancer cells. Besides enhanced mTOR-dependent proteasomal degradation of Pdcd4 protein, we found that Pdcd4 transcription is negatively regulated by mTOR signaling, and localized cis-acting element in Pdcd4 promoter responsible for this effect. In conclusion, we described a novel molecular mechanism of Pdcd4 suppression in cancer cells consisting from mTOR signaling-dependent transcriptional repression of Pdcd4. [Copyright &y& Elsevier]

Abstract: Dipeptidyl peptidase IV (DPPIV) was studied in three human lung cells – P (fetal lung-derived cells), A549 (lung adenocarcinoma) and SK-MES-1 (squamous cell carcinoma) using a fluorescent cytochemical procedure developed on the basis of the substrate 4-(glycyl-l-prolyl hydrazido)-N-hexyl-1,8-naphthalimide. The observed differences in the enzyme expression were confirmed by measuring the enzyme hydrolysis of glycyl-l-prolyl-para-nitroanilide. The surface and total dipeptidyl peptidase activities of P cells were correspondingly 7–8 and 3–10 times higher than those of SK-MES-1 and A549 cells. The ratio surface per total activity showed that in P (95%) and A549 (93%) cells the enzyme is associated with the plasmalemma while in SK-MES-1 cells (35%) it is bound to intracellular membranes. In order to compare the results from cell cultures with those in human tumor, the enzyme activity was investigated in cryo-sections of three cases of diagnosed squamous lung carcinoma. DPPIV activity was restricted to the connective tissue stroma surrounding the DPPIV-negative tumor foci. [Copyright &y& Elsevier]

• Ce6 mediated PDT could induce obvious DNA damage and activate ATM-related DNA damage response (DDR) through generation of ROS in a short period time. • ATM inhibitor could ameliorate the efficacy of Ce6-triggered PDT for lung cancer by blocking the DDR. • The present study reveals a novel resistance mechanism of PDT and proposes an intervention strategy by the use of ATM inhibitor. Photodynamic therapy (PDT) is a promising strategy for the treatment of malignant tumors due to its high selectivity, limited-toxicity, and non-invasiveness. However, PDT can also induce DNA damage and subsequent repair response, which may reduce the efficacy of PDT. In the present study, we sought to explore the effect of chlorin e6 (Ce6)-mediated PDT on DNA damage and DNA damage response (DDR) in lung cancer cells. In addition, the effect of PDT combined with ATM inhibitor on molecules of DDR and the possibility of improving the efficacy of PDT were further investigated. In the in vitro study, lewis cells were submitted to Ce6 treatment (2, 4, 8, 16, 32 μg/mL). To determine the concentration of Ce6, uptake and toxicity of Ce6 mediated PDT were detected using flow cytometry (FACS), Confocal microscopy, and CCK-8. In the subsequent research, 8 μg/mL of Ce6 was the treatment condition for inducing PDT. The different post-irradiation placement times were further grouped under this condition (2, 4, 6, 12 h). Cellular reactive oxygen species (ROS), damage of DNA were measured by DCFH-DA probe, comet assay respectively. Then the expression of p-ATM, p53, and γ-H2A.X proteins related to DNA damage response, was detected by WB. The efficacy of Ce6 induced PDT was also demonstrated by Annexin-V/PI staining as well as the expression of PCNA, cleaved-caspase-3. On this basis, ATM inhibitor was applied to treat lewis cells combined with Ce6 (2, 4 h) to investigate whether the efficacy of PDT induced by Ce6 can be improved after the ATM-related DDR was blocked. The cell viability, apoptosis, and expression of associated proteins were assayed. At 2–4 h after PDT treatment, ROS was dramatically elevated in lewis cells, DNA double-strand breaks (DDSB) occurred, as well as up-regulation of DDR proteins γ-H2A.X, p-ATM, and p53. At the same time, lewis cells did not undergo significant apoptosis. After ATM inhibition, the DDR was significantly blocked within 2–4 h after Ce6 induced PDT, along with a pronounced decrease in cell viability followed by a prominent increase of apoptosis. Ce6-mediated PDT generates ROS in a short period time, thus inducing DNA damage, ATM-related DDR as well as promoting resistance of lung cancer cells to PDT. Combining ATM inhibitor with PDT could effectively inhibit the DDR induced by PDT, thereby enhancing the efficacy. This study reveals a new resistance mechanism of PDT and proposes an intervention strategy. [ABSTRACT FROM AUTHOR]