Association of p73 G4C14‐to‐A4T14 polymorphism at exon 2 with the response of human lung adenocarcinoma cell lines to chemotherapy

In order to assess the effect of p73 gene polymorphism G4C14‐A4T14 on cisplatin‐based chemosensitivity of human lung adenocarcinoma cell lines, we examined the differences in biological character and drug sensitivity affected by cisplatin between human lung adenocarcinoma cell lines A549 and P15. The allelic expression ofp73 in A549 and P15 was studied by Sty I polymorphism analysis. MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay was used to analyse the response of these two cell lines to cisplatin. The changes in the biological behaviour of the cells were observed by colony formation assay. The drug‐induced apoptosis of cells was measured by Hoechst and TUNEL techniques. Homozygous allelic expression was demonstrated in the two cell lines. AT/AT genotype appeared in A549, GC/GC genotype was detected in P15. Although the colony formation number decreased with an increasing cisplatin dose (P<0.05), there was no significant difference in colony‐formation rate in these two cell lines (P>0.05). MTT assay also determined that the 50% inhibitory concentration (IC₅₀) for A549 and P15 was 8.9 and 11.6 μmol/l, respectively; the IC₅₀ value did not differ significantly between A549 and P15 (P>0.05). The cell apoptosis induced by cisplatin was demonstrated in both A549 and P15. P73 G4C14‐A4T14 polymorphisms at exon 2 existed in human NSCLC (non‐small‐cell lung cancer) cell lines. Our data in vitro suggest that p73 G4C14‐A4T14 polymorphism has no significant relationship to the cisplatin‐based chemosensitivity in human lung adenocarcinoma.     

肺腺癌A549/DDP细胞周期变化及其多药耐药性

用Fura-2/AM标记药物敏感的肺腺癌细胞A₅₄₉和抗顺铂药物的肺腺癌细胞A₅₄₉/DDP两种细胞胞内游离Ca²⁺,用碘化丙锭(PI)标记细胞DNA,检测其胞内Ca²⁺的变化及两种细胞增殖能力和细胞周期.实验结果表明,抗药性细胞株A₅₄₉/DDP胞浆内游离Ca²⁺的浓度仅为药物敏感细胞株A₅₄₉的1/3左右,同时前者的细胞增殖能力较后者明显增强,而且细胞周期也明显缩短.当用BAPTA-AM和EGTA或A₂₃₁₈₇和Thapsigargin处理细胞以降低或升高其胞内自由Ca²⁺浓度时可改变细胞的生长周期,二者也呈现明显差别.这些结果表明,对顺铂产生耐药性的人肺腺癌A₅₄₉/DDP细胞胞内Ca²⁺浓度的降低,可能影响细胞的增殖,缩短细胞的生长周期,特别是影响起决定作用的G1期,从而有利于肿瘤细胞多药耐药特性的维持.     

JA,a new type of polyunsaturated fatty acid isolated from <Emphasis Type="Italic">Juglans mandshurica</Emphasis> Maxim,limits the survival and induces apoptosis of heptocarcinoma cells

Juglans mandshurica Maxim (Juglandaceae) is a famous folk medicine for cancer treatment and some natural compounds isolated from it have been studied extensively. Previously we isolated a type of ω-9 polyunsaturated fatty acid (JA) from the bark of J. mandshurica, however little is known about its activity and the underlying mechanisms. In this study, we studied anti-tumor activity of JA on several human cancer cell lines. Results showed that JA is cytotoxic to HepG2, MDA-MB-231, SGC-7901, A549 and Huh7 cells at a concentration exerting minimal toxic effects on L02 cells. The selective toxicity of JA was better than other classical anti-cancer drugs. Further investigation indicated that JA could induce cell apoptosis, characterized by chromatin condensation, DNA fragmentation and activation of the apoptosis-associated proteins such as Caspase-3 and PARP-1. Moreover, we investigated the cellular apoptosis pathway involved in the apoptosis process in HepG2 cells. We found that proteins involved in mitochondrion (cleaved-Caspase-9, Apaf-1, HtrA2/Omi, Bax, and Mitochondrial Bax) and endocytoplasmic reticulum (XBP-1s, GRP78, cleaved-Caspase-7 and cleaved-Caspase-12) apoptotic pathways were up-regulated when cells were treated by JA. In addition, a morphological change in the mitochondrion was detected. Furthermore, we found that JA could inhibit DNA synthesis and induce G₂/M cell cycle arrest. The expression of G₂-to-M transition related proteins, such as CyclinB1 and phosphorylated-CDK1, were reduced. In contrast, the G₂-to-M inhibitor p21 was increased in JA-treated cells. Overall, our results suggest that JA can induce mitochondrion- and endocytoplasmic reticulum-mediated apoptosis, and G₂/M phase arrest in HepG2 cells, making it a promising therapeutic agent against hepatoma.     

Effects of lysophosphatidic acid (LPA) receptor-2 (LPA2) and LPA3 on the regulation of chemoresistance to anticancer drug in lung cancer cells

Lysophosphatidic acid (LPA) mediates a variety of biological functions via the binding of G protein-coupled LPA receptors (LPA receptor-1 (LPA₁) to LPA₆). This study aimed to investigate the roles of LPA₂ and LPA₃ in the modulation of chemoresistance to anticancer drug in lung cancer A549 cells. In cell survival assay, cells were treated with cisplatin (CDDP) every 24 h for 2 days. The cell survival rate to CDDP of A549 cells was significantly elevated by an LPA₂ agonist, GRI-977143. To evaluate the roles of LPA₂-mediated signaling in cell survival during tumor progression, highly migratory (A549-R10) cells were generated from A549 cells. In the presence of GRI-977143, the cell survival rate to CDDP of A549-R10 cells were markedly higher than that of A549 cells, correlating with LPAR2 expression level. Moreover, to assess the effects of long-term anticancer drug treatment on cell survival, the long-term CDDP treated (A549-CDDP) cells were established from A549 cells. The cell survival rate to CDDP of A549-CDDP cells was elevated by GRI-977143. Since LPAR3 expression level was significantly higher in A549-CDDP cells than in A549 cells, we investigated the roles of LPA₃ in the cell survival to CDDP of A549 cells, using an LPA₃ agonist, 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate ((2S)-OMPT). The cell survival rate to CDDP of A549 cells was significantly reduced by (2S)-OMPT treatment. In the presence of (2S)-OMPT, the cell survival rate to CDDP of A549 cells was elevated by LPA₃ knockdown. These results suggest that LPA signaling via LPA₂ and LPA₃ is involved in the regulation of chemoresistance in A549 cells treated with CDDP.     

Synthesis and antiproliferative evaluation of 6-arylindeno[1,2-c]quinoline derivatives

A number of 6-arylindeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferative activities against the growth of five cancer cell lines including human hepatocelluar carcinoma (Hep G2, Hep 3B and Hep2.2.1), non-small cell lung cancer (A549 and H1299), and normal diploid embryonic lung cell line (MRC-5). The preliminary results indicated that 9-(3-(dimethylamino)propoxy)-6-(4-(3-(dimethylamino)propoxy)phenyl)-2-fluoro-11H-indeno[1,2-c]quinolin-11-one (14c) was the most potent with GI₅₀ values of 0.61, 0.67, 0.59, and 0.72 μM against the growth of Hep G2, Hep 3B, Hep 2.2.1, and H1299 cells, respectively. Results have also shown that 2,9-bis(3-(dimethylamino)propoxy)-6-(4-(3-(dimethylamino)propoxy)phenyl)-11H-indeno[1,2-c]quinolin-11-one (17), which exhibited GI₅₀ of 0.60 and 0.68 μM against the growth of Hep G2 and A549, respectively, was more active than the positive topotecan and irinotecan. Compound 17 was less toxic than topotecan against the growth of normal cell (MRC-5) and therefore, was selected for further evaluation. Results indicated that compound 17 induce cell cycle arrest in G2/M phase, DNA fragmentation, and disrupt the microtubule network in A549 cells. The apoptotic induction may through the cleavage of PARP.     

Induction of p53‐independent growth inhibition in lung carcinoma cell A549 by gypenosides

The objectives of this study are to investigate antiproliferative effect and mechanisms of bioactive compounds from Gynostemma pentaphyllum (G. pentaphyllum) on lung carcinoma cell A549. Saponins, carotenoids and chlorophylls were extracted and fractionated by column chromatography, and were subjected to high‐performance liquid chromatography‐mass spectrometry analyses. The saponin fraction, which consisted mainly of gypenoside (Gyp) XXII and XXIII, rather than the carotenoid and chlorophyll ones, was effective in inhibiting A549 cell growth in a concentration‐ and a time‐dependent manner as evaluated using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The estimated half maximal inhibitory concentration (IC₅₀) of Gyp on A549 cells was 30.6 μg/ml. Gyp was further demonstrated to induce an apparent arrest of the A549 cell cycle at both the S phase and the G2/M phase, accompanied by a concentration‐ and a time‐dependent increase in the proportions of both the early and late apoptotic cells. Furthermore, Gyp down‐regulated cellular expression of cyclin A and B as well as BCL‐2, while up‐regulated the expression of BAX, DNA degradation factor 35 KD, poly [ADP‐ribose] polymerase 1, p53, p21 and caspase‐3. Nevertheless, both the treatment of a p53 inhibitor, pifithrin‐α, and the small hairpin RNA‐mediated p53 knockdown in the A549 cells did not alter the growth inhibition effect induced by Gyp. As a result, the cell cycle arrest and apoptosis of A549 cells induced by Gyp would most likely proceed through p53‐independent pathway(s).     

Homocysteine modulates the proteolytic potential of human arterial smooth muscle cells through a reactive oxygen species dependant mechanism

Suberoyl bishydroxamic acid (SBHA) as a histone deacetylase (HDAC) inhibitor has various cellular effects such as cell growth and apoptosis. In the present study, we evaluated the effects of SBHA on the growth and death of A549 lung cancer cells. SBHA inhibited the growth of A549 cells with an IC₅₀ of approximately 50 μM at 72 h in a dose-dependent manner. DNA flow cytometric analysis indicated that SBHA induced a G2/M phase arrest of the cell cycle. This agent also induced apoptosis, as evidenced by sub-G1 cells and annexin V-FITC staining cells. SBHA-induced apoptosis was accompanied by the loss of mitochondrial membrane potential (MMP; ΔΨ_m), Bcl-2 decrease, Bax increase, and the activation of caspase-3. All of the tested caspase inhibitors significantly rescued some cells from SBHA-induced A549 cell death. However, none of the caspase inhibitors prevented the loss of MMP (ΔΨ_m) induced by SBHA. Intracellular reactive oxygen species (ROS) levels including O ₂ ^?? were increased in 50 μM SBHA-treated A549 cells. None of the caspase inhibitors attenuated ROS levels in these cells. SBHA also elevated the number of glutathione (GSH)-depleted cells in A549 cells, which was reduced by treatment with caspase inhibitors. In conclusion, this is the first report that SBHA inhibited the growth of A549 lung cancer cells via caspase-dependent apoptosis, which was related to GSH depletion rather than changes in ROS level.     

Synthesis and antiproliferative evaluation of 6-aryl-11-iminoindeno[1,2-c]quinoline derivatives

A number of 6-aryl-11-iminoindeno[1,2-c]quinoline derivatives were synthesized and evaluated for their antiproliferative activities. Among them, (E)-6-{4-[3-(dimethylamino)propoxy]phenyl}-2-fluoro-9-hydroxy-11H-indeno[1,2-c]quinolin-11-one O-3-(dimethylamino)propyl oxime (23a) was the most active, exhibited GI₅₀ values of 0.64, 0.39, 0.55, 0.67, and 0.65 μM against the growth of Hep G2, Hep 3B, A549, H1299, and MDA-MB-231, respectively. Compound 23a inhibited the growth of hepatoma cell lines in a dose- and time-dependent manner. The proportion of cells was decreased in the G1 and accumulated in G2/M phase after 12 h treatment of 23a, while the hypodiploid (sub-G0/G1 phase) cells increased. Further investigations have shown that 23a induced cell cycle arrest at G2/M phase and induce apoptosis via activation of p53, Bax, and caspase-8 which consequently cause cell death.     

Synthesis of 9‐(Heteroarylmethylidene)amino Derivatives of Homocamptothecin with Biological Activities

Six 9‐(heteroarylmethylidene)amino derivatives, 2a – 2f , of homocamptothecin were synthesized for the first time by total synthesis in 22 steps and biologically evaluated as inhibitors of topoisomerase I. Moreover, the antitumor activities of 2a – 2f against three human tumor cell lines, i.e., A‐549, MDA‐MB‐435, and HCT‐116, were determined and the results showed that compound 2c was the most active homocamptothecin derivative against the A‐549 (IC₅₀=0.046 μM ) and HTC‐116 tumor cells (IC₅₀=3.67 μM ), with a ca. 50 times higher activity than the reference drug topotecan (TPT) against the lung cancer cell line A‐549.     

NMR studies of the relationship between the changes of membrane lipids and the cisplatin-resistance of A549/DDP cells

Changes of membrane lipids in cisplatin-sensitive A549 and cisplatin-resistant A549/DDP cells during the apoptotic process induced by a clinical dose of cisplatin (30 μM) were detected by ¹H and ³¹P-NMR spectroscopy and by membrane fluidity measurement. The apoptotic phenotypes of the two cell lines were monitored with flow cytometry. The assays of apoptosis showed that significant apoptotic characteristics of the A549 cells were induced when the cells were cultured for 24 hours after treatment with cisplatin, while no apoptotic characteristic could be detected for the resistant A549/DDP cells even after 48 hours. The results of ¹H-NMR spectroscopy demonstrated that the CH₂/CH₃ and Glu/Ct ratios of the membrane of A549 cells increased significantly, but those in A549/DDP cell membranes decreased. In addition, the Chol/CH₃ and Eth/Ct ratios decreased for the former but increased for the latter cells under the same conditions. ³¹P-NMR spectroscopy indicated levels of phosphomonoesters (PME) and ATP decreased in A549 but increased in A549/DDP cells after being treated with cisplatin. These results were supported with the data obtained from ¹H-NMR measurements. The results clearly indicated that components and properties of membrane phospholipids of the two cell lines were significantly different during the apoptotic process when they were treated with a clinical dose of cisplatin. Plasma membrane fluidity changes during cisplatin treatment as detected with the fluorescence probe TMA-DPH also indicate marked difference between the two cell lines. We provided evidence that there are significant differences in plasma membrane changes during treatment of cisplatin sensitive A549 and resistant A549/DDP cells.     

Alteration of membrane lipid biophysical properties and resistance of human lung adenocarcinoma A549 cells to cisplatin

Alterations of membrane lipid biophysical properties of sensitive A₅₄₉ and resistant A₅₄₉/DDP cells to the Cis-dichlorodiammine platinum (Cisplatin) were performed by measurements of fluorescence and flow cytometry approaches using fluorescence dyes of DPH, N-AS and Merocyanine 540 (MC 540) respectively. Fatty acids of membrane lipid of the two cell lines were analyzed by gas chromatography. The results indicated clearly that fluorescence polarization (P) of the DPH probe is 0.169 for the sensitive A₅₄₉ cell and 0.194 for the resistant A₅₄₉/DDP cells. Statistical analysis showed significant difference between the two cell lines. The polarizations of 2-AS and 7-AS which reflect the fluidity of surface and middle of lipid bilayer are 0.134 and 0.144 for the sensitive A549 cells as well as 0.171 and 0.178 for the resistant A₅₄₉/DDP cells respectively, but there is no significant difference of the polarization of 12-AS between the two cell lines. This shows that alterations of the membrane fluidity of both cells were mainly located on the surface and middle of the lipid bilayer. In addition, the packing density of phospholipid molecules in the membrane of the two cell lines detected by MC540 probe indicated that lipid packing of A₅₄₉ cell membranes was looser than that of the A₅₄₉/DDP cells. And unsaturation degree of plasma membrane fatty acids of the A₅₄₉/DDP cells was also lower than that of A₅₄₉ cells. Taken together, it was proposed that the alteration of membrane lipid biophysical state may be involved in the resistance of A₅₄₉/DDP cells to cisplatin.     

Acetone extract of Angelica sinensis inhibits proliferation of human cancer cells via inducing cell cycle arrest and apoptosis

Angelica sinensis (Oliv.) Diels, a traditional Chinese medicine, has been widely prescribed in treatment of gynecological diseases. Bio-based assays for extracts of Angelica sinensis showed that the acetone extract (AE-AS) had dose-dependently antiproliferative effect on A549, HT29, DBTRG-05MG and J5 human cancer cells. The IC₅₀ values of AE-AS on mentioned cancer cells ranged from 35 to 50 μg/ml after 24 h of treatment. After 72 h of exposure, AE-AS (40 μg/ml) significantly reduced A549 cell proliferation to 24 ± 3.2% of control. In A549 cells, the cell cycle analysis showed that AE-AS induced a significant increase in the number of cells in G0/G1, with a concomitant decrease in the number of cells in S phase. AE-AS-induced chromatin changes and apoptosis of A549 cells were confirmed by Hoechst 33342 DNA staining and annexin V staining. A549 cells treated with AE-AS caused activation of caspase-9 and -3, and AE-AS-induced apoptosis could be inhibited by the broad-spectrum caspase inhibitor, z-VAD-fmk. The Western blot indicated the AE-AS-triggered apoptosis is mediated via suppression of Bcl-2 oncoprotein expression rather than p53 or Bax. Besides, AE-AS decreased the levels of cdk4 protein was observed. These results indicate that the AE-AS could induce G1/S arrest and activate the mechanism of apoptosis in human cancer cells. Extracts obtained from different methods of fractionation might possess distinct bioactivity. These results prompted us to further evaluate the in vivo anticancer effects and elucidate the chemical composition profile of AE-AS.     

Design and Synthesis of Novel Cytotoxic Indole‐Thiosemicarbazone Derivatives: Biological Evaluation and Docking Study

In this work, two novel series of indole‐thiosemicarbazone derivatives were designed, synthesized, and evaluated for their cytotoxic activity against MCF‐7, A‐549, and Hep‐G2 cell lines in comparison to etoposide and colchicine as the reference drugs. Generally, the synthesized compounds showed better cytotoxicity towards A‐549 and Hep‐G2 than MCF‐7. Among them, (2E)‐2‐{[2‐(4‐chlorophenyl)‐1H‐indol‐3‐yl]methylidene}‐N‐(4‐methoxyphenyl)hydrazinecarbothioamide ( 8l ) was found to be the most potent compound against A‐549 and Hep‐G2, at least three times more potent than etoposide. The morphological analysis by the acridine orange/ethidium bromide double staining test and flow cytometry analysis indicated that compound 8l induced apoptosis in A‐549 cells. Moreover, molecular docking methodology was exploited to elucidate the details of molecular interactions of the studied compounds with putative targets.     

The microtubule depolymerizing agent naphthazarin induces both apoptosis and autophagy in A549 lung cancer cells

Naphthazarin (DHNQ, 5,8-dihydroxy-l,4-naphthoquinone) is a naturally available 1,4-naphthoquinone derivatives. In this study, we focused on elucidating the cytotoxic mechanism of naphthazarin in A549 non-small cell lung carcinoma cells. Naphthazarin reduced the A549 cell viability considerably with an IC₅₀ of 16.4 ± 1.6 μM. Naphthazarin induced cell death in a dose- and time-dependent manner by activating apoptosis and autophagy pathways. Specifically, we found naphthazarin inhibited the PI3K/Akt cell survival signalling pathway, measured by p53 and caspase-3 activation, and PARP cleavage. It also resulted in an increase in the ratio of Bax/Bcl2 protein levels, indicating activation of the mitochondrial apoptotic pathway. Similarly naphthazarin triggered LC3II expression and induced autophagic flux in A549 cells. We demonstrated further that naphthazarin is a microtubule inhibitor in cell-free system and in A549 cells. Naphthazarin treatment depolymerized interphase microtubules and disorganised spindle microtubules and the majority of cells arrested at the G₂/M transition. Together, these data suggest that naphthazarin, a microtubule depolymerizer which activates dual cell death machineries, could be a potential novel chemotherapeutic agent.     

Efficient induction of ginsenoside biosynthesis and alteration of ginsenoside heterogeneity in cell cultures of Panax notoginseng by using chemically synthesized 2-hydroxyethyl jasmonate

Chemically synthesized 2-hydroxyethyl jasmonate (HEJA) was for the first time employed to induce the ginsenoside biosynthesis and to manipulate the product heterogeneity in plant cell cultures. The dose response and timing of HEJA elicitation were investigated in cell suspension cultures of Panax notoginseng. The optimal concentration and timing of HEJA addition for both cell growth and ginsenoside accumulation was identified to be 200 μM added on day 4. It was interestingly found that HEJA could stimulate ginsenosides biosynthesis and change their heterogeneity more efficiently than methyl jasmonate (MJA), i.e., the total ginsenoside content and the Rb/Rg ratio increased about 60 and 30% with HEJA elicitation than that by MJA, respectively. The activity of Rb₁ biosynthetic enzyme, i.e., UDPG-ginsenoside Rd glucosyltransferase (UGRdGT), was also higher in the former case. A maximal production titer of ginsenoside Rg₁, Re, Rb₁, and Rd was 47.4±4.8, 52.3±4.4, 190±18, and 12.1±2.5 mg/l with HEJA elicitation, which was about 1.3-, 1.3-, 1.7-, and 2.1-fold than that using MJA, respectively. Early signal events in plant defense response, including oxidative burst and jasmonic acid (JA) biosynthesis, were also examined. Levels of H₂O₂ and NO in medium and l-phenylalanine ammonia lyase activity in cells were not affected by addition of MJA and HEJA. On the other hand, the JA content in cells was increased with external jasmonates elicitation, and it was inhibited with the addition of JA biosynthesis inhibitors. The results suggest that oxidative burst might not be involved in the jasmonates-elicited signal transduction pathway, and MJA and HEJA may induce the ginsenoside biosynthesis via induction of endogenous JA biosynthesis and key enzymes (such as UGRdGT) in the ginsenoside biosynthetic pathway of P. notoginseng cells. The information is useful for hyperproduction of plant-specific heterogeneous products.     

Alteration of membrane lipid biophysical properties and resistance of human lung adenocarcinoma A549 cells to cisplatin

Alterations of membrane lipid biophysical properties of sensitive A₅₄₉ and resistant A₅₄₉/DDP cells to the Cis-dichlorodiammine platinum (Cisplatin) were performed by measurements of fluorescence and flow cytometry approaches using fluorescence dyes of DPH, N-AS and Merocyanine 540 (MC 540) respectively. Fatty acids of membrane lipid of the two cell lines were analyzed by gas chromatography. The results indicated clearly that fluorescence polarization (P) of the DPH probe is 0.169 for the sensitive A₅₄₉ cell and 0.194 for the resistant A₅₄₉/DDP cells. Statistical analysis showed significant difference between the two cell lines. The polarizations of 2-AS and 7-AS which reflect the fluidity of surface and middle of lipid bilayer are 0.134 and 0.144 for the sensitive A549 cells as well as 0.171 and 0.178 for the resistant A₅₄₉/DDP cells respectively, but there is no significant difference of the polarization of 12-AS between the two cell lines. This shows that alterations of the membrane fluidity of both cells were mainly located on the surface and middle of the lipid bilayer. In addition, the packing density of phospholipid molecules in the membrane of the two cell lines detected by MC540 probe indicated that lipid packing of A₅₄₉ cell membranes was looser than that of the A₅₄₉/DDP cells. And unsaturation degree of plasma membrane fatty acids of the A₅₄₉/DDP cells was also lower than that of A₅₄₉ cells. Taken together, it was proposed that the alteration of membrane lipid biophysical state may be involved in the resistance of A₅₄₉/DDP cells to cisplatin.     

Synthesis and biological evaluation of new bisindole-imidazopyridine hybrids as apoptosis inducers

A series of diindolylmethanes (5a-t) were designed, synthesized, and examined for their cytotoxicity against four human cancer cell lines like prostate (DU-145), lung (A549), breast (MCF-7) and cervical cancer (HeLa). These results revealed that among all the hybrids, two (5k and 5r) were identified and exhibited significant cytotoxic effect against A549 cancer cells with IC₅₀ values of 1.65 ± 0.3 and 1.80 ± 0.8 µM respectively. To investigate the reasons for the cytotoxic activity, the conventional biological assays were carried out with 5k and 5r on the A549 cancer cells. Both hybrids led to the arrest of A549 cell lines at the G2/M phase of the cell cycle and strongly induced apoptosis. Further the apoptotic effects of 5k and 5r were confirmed by ROS, annexin-V FITC, and mitochondrial membrane potential. Moreover, structure–activity relationships were elucidated with various substitutions on these hybrids.     

Arthpyrone L,a New Pyridone Alkaloid from a Deep-Sea Arthrinium sp., Inhibits Proliferation of MG63 Osteosarcoma Cells by Inducing G0/G1 Arrest and Apoptosis

Fractionation of the ethanol extract of a marine fungus, Arthrinium sp., afforded a new pyridone alkaloid (arthpyrone L ( 1 )), the structure with absolute configuration of which was established by comprehensive spectroscopic analyses. In vitro cell viability assays revealed that compound 1 showed antiproliferative effects toward human A549 (lung), MG63, U2OS (bone), MCF-7 and MDA-MB-231 (breast) cancer cells. MG63 cell lines were chosen for further biological evaluations and presented apoptosis and cell cycle arrest (G0/G1 phase) upon treatment of 1 . Subsequent mechanism studies demonstrated that the growth inhibition of 1 against MG63 cells was via activation of caspase-modulated apoptotic pathway and inhibition of PI3K/Akt pathway.     

Dopaminergic and adrenergic toxicities on SK-N-MC human neuroblastoma cells are mediated through G protein signaling and oxidative stress

Dopamine and norepinephrine are neurotransmitters which participate in various regulatory functions of the human brain. These functions are lost in neurodegenerative diseases including Parkinson’s disease and Alzheimer’s disease. In this study, we used SK-N-MC neuroblastoma cells to investigate the cytotoxicities of high concentrations of dopamine and norepinephrine on neuronal cells. Dopamine, norepinephrine, as well as their corresponding synthetic agonists (SKF38393 and isoproterenol, respectively) triggered SK-N-MC cell death when applied at 50–100 μM persistently for 2 days. This catecholamine-induced cell death appears to be neuronal specific, as demonstrated by their inabilities of triggering apoptosis of A549 lung carcinoma cells and Cos-7 kidney fibroblasts. By pretreating SK-N-MC cells with target-specific inhibitors before administration of catecholamine, components of G protein signaling (i.e. G _s /cAMP/PKA), monoamine oxidases, nitric oxide synthase, c-Jun N-terminal kinase and oxidative stress were found to be involved in this dopamine/norepinephrine-induced cytotoxicity, which subsequently led to caspase-dependent and -independent apoptotic responses as well as DNA degradation. In contrast, agonists of G _i -coupled dopamine receptors and adrenergic receptors (quinpirole and UK14,304, respectively) were incapable of triggering apoptosis of SK-N-MC cells. Our results suggest that both G protein (G _s )-mediated signaling cascade and oxidative stress participate in the dopamine/norepinephrine-induced neuronal apoptosis. Anthony Chan and Ng Contributed equally to this work.     

Silence of lncRNA UCA1 rescues drug resistance of cisplatin to non–small-cell lung cancer cells

The aim of this study was to investigate the effect of long noncoding RNA (lncRNA) urogenital carcinoma antigen 1 (UCA1) on drug resistance in A549/DDP cell and explore its underlying mechanism. The inhibition rate and IC ₅₀ of DDP were detected in A549 and A549/DDP cells by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay. The expression of lncRNA UCA1 was measured in A549 and A549/DDP cells by quantitative real-time polymerase chain reaction. The expressions of N-cadherin, E-cadherin, vimentin, and Snail were detected in A549 and A549/DDP cells by Western blot analysis. Results showed that the IC ₅₀ of DDP was 16.20 ± 2.27 μmol/L and 69.72 ± 4.83 μmol/L in A549 and A549/ DDP cells, respectively. Compared with the A549 group, the expressions of N-cadherin, vimentin, and Snail was significantly upregulated in A549/DDP group, but E-cadherin was significantly downregulated. Compared with the shCon group, the abundance of N-cadherin, vimentin, and Snail was significantly downregulated in short hairpin RNA UCA1 (shUCA1) group, while E-cadherin was significantly upregulated. Cell migration and invasion were significantly suppressed and IC ₅₀ was reversed to 16.20 ± 2.27 μmol/L in the shUCA1 group. Silencing lncRNA UCA1 inhibited the migration and invasion of A549/DDP cells and reversed the resistance of A549/DDP cells to DDP. The mechanism might be related to downregulation of epithelial-mesenchymal transition, which will provide a new direction for the treatment of non–small-cell lung cancer with cisplatin.