Icaritin suppresses the proliferation of human osteosarcoma cells in vitro by increasing apoptosis and decreasing MMP expression

Aim： To explore whether icaritin, a prenylflavonoid derivative of the Chinese tonic herb Epimedium, could suppress the proliferation of human osteosarcoma cells in vitro, and to elucidate the mechanisms of the action.
Methods： Human osteosarcoma SaOS2 cell line was used in the present study. The proliferation of the cells was examined using MTT assay and immunofluorescence DAPI staining. Cell motility was studied with the scratch assay. Cell apoptosis was determined by Annexin V-FITC and PI double staining using flow cytometry. Western blotting and RT-PCR were used to measure the expression of mRNAs and proteins in the cells.

Results： Icaritin （5–15 μmol/L） suppressed the proliferation of SaOS2 cells in vitro in a dose-dependent manner. Furthermore, the cell motility was significantly decreased after exposure to icaritin. Moreover, icaritin （5 μmol/L） time-dependently induced the apoptosis of SaOS2 cells, markedly suppressed MMP-2 and MMP-9 expression, upregulated caspase-3 and caspase-9 expression, and increased the level of cleaved caspase-3 in the cells. Co-exposure to the caspase-3 inhibitor zVAD-fmk （10 μmol/L） compromised the icaritin-induced caspase-3 expression and apoptosis in SaOS2 cells.

Conclusion： Icaritin suppresses the proliferation of SaOS2 human osteosarcoma cells by increasing apoptosis and downregulating MMP expression.     

Telekin suppresses human hepatocellular carcinoma cells in vitro by inducing G2/M phase arrest via the p38 MAPK signaling pathway

Aim:

Telekin, isolated from the Chinese herb Carpesium divaricatum, has shown anti-proliferation effects against various cancer cells, including hepatocellular carcinoma cells. In this study, we investigated the anti-proliferation mechanisms of telekin in human hepatocellular carcinoma HepG2 cells in vitro.

Methods:

HepG2 cells were treated with telekin. Cell viability was evaluated using MTT assay. Flow cytometry was used to measure cell cycle profiles, ROS level and apoptosis. The protein expression levels were analyzed with Western blotting.

Results:

Telekin (3.75–30 μmol/L) dose-dependently inhibited the viability of HepG2 cells and induced l apoptosis. Furthermore, the treatment induced cell cycle arrest at G₂/M phase, accompanied by significantly increased the phosphorylation of Cdc25A and Cdc2, and decreased Cyclin B1 level. Moreover, the treatment significantly stimulated ROS production, and increased the phosphorylation of p38 and MAPKAPK-2 in the cells. Pretreatment with the antioxidant NAC (2.5, 5, and 10 mmol/L), or the p38 MAPK inhibitor SB203580 (2.5 and 5 μmol/L) dose-dependently attenuated these telekin-induced effects in the cells.

Conclusion:

Telekin suppresses hepatocellular carcinoma cells in vitro by inducing G₂/M phase arrest via activating the p38 MAPK pathway.     

Betulinic acid inhibits autophagic flux and induces apoptosis in human multiple myeloma cells in vitro

Aim:

To investigate the effects of betulinic acid (BA) on apoptosis and autophagic flux in multiple myeloma cells and the relationship between the two processes.

Methods:

The proliferation of human multiple myeloma KM3 cells was measured with MTT assay. FITC/PI double-labeled flow cytometry (FCM) and Hoechst 33258 staining were used to analyze the cell apoptosis. Caspase 3, PARP, Beclin1, LC3-II, and P62 were detected using Western blotting.

Results:

Treatment of KM3 cells with BA (5−25 μg/mL) suppressed the cell proliferation in time- and dose-dependent manners. The IC₅₀ values at 12, 24, and 36 h were 22.29, 17.36, and 13.06 μg/mL, respectively. BA treatment dose-dependently induced apoptosis of KM3 cells, which was associated with the activation of caspase 3. However, Z-DEVD-FMK, a specific inhibitor of caspase 3, did not decrease, but rather sensitized the cells to BA-induced apoptosis, suggesting an alternative mechanism involved. On other hand, BA treatment dose-dependently increased the accumulation of LC3-II and P62 in KM3 cells, representing the inhibition of autophagic flux. Furthermore, BA treatment dose-dependently downregulated the expression of Beclin 1, an important inducer of autophagy, in KM3 cells. In the presence of BA, Z-DEVD-FMK induced autophagy and increased the amount of LC3-II in KM3 cells, which may occur via attenuating BA-induced decrease in the level of Beclin 1. Similarly, rapamycin, an autophagy inducer, increased the amount of LC3-II in KM3 cells. In the presence of BA, rapamycin caused further increase in the amount of LC3-II. Furthermore, rapamycin sensitized BA-treated KM3 cells to apoptosis.

Conclusion:

The results demonstrate that BA induces apoptosis and blocks autophagic flux in KM3 cells. Furthermore, in addition to activation of caspase 3, the inhibition of autophagic flux also contributes to the BA-mediated apoptosis of KM3 cells.     

S-allylcysteine,a garlic derivative,suppresses proliferation and induces apoptosis in human ovarian cancer cells in vitro

Aim： To investigate the effects of S-allylcysteine （SAC）, a water-soluble garlic derivative, on human ovarian cancer cells in vitro. Methods： Human epithelial ovarian cancer cell line A2780 was tested. Cell proliferation was examined with CCK-8 and colony formation assays. Cell cycle was analyzed with flow cytometry. Cell apoptosis was studied using Hoeohst 33258 staining and Annexin V/PI staining with flow cytometry. The migration and invasion of A2780 cells were examined with transwell and wound healing assays. The expression of relevant proteins was detected with Western blot assays. Results： SAC （1-100 mmol/L） inhibited the proliferation of A2780 cells in dose- and time-dependent manners （the ICsovalue was approximately 25 mmoVL at 48 h, and less than 6.25 mmol/L at 96 h）. Furthermore, SAC dose-dependently inhibited the colony formation of A2780 cells. Treatment of A2780 cells with SAC resulted in G/S phase arrest and induced apoptosis, accompanied by decreased expression of pro-caspase-3, Parp-1 and Bcl-2, and increased expression of active caspase-3 and Bax. SAC treatment significantly reduced the migration of A2780 cells, and markedly decreased the protein expression of Wnt5a, p-AKT and c-Jun, which were the key proteins involved in proliferation and metastasis. Conclusion： SAC suppresses proliferation and induces apoptosis in A2780 ovarian cancer cells in vitro.     

In vitro anti-cancer activity of chamaejasmenin B and neochamaejasmin C isolated from the root of Stellera chamaejasme L

Aim:

To examine the anti-cancer effects of chamaejasmenin B and neochamaejasmin C, two biflavonones isolated from the root of Stellera chamaejasme L (known as the traditional Chinese herb Rui Xiang Lang Du) in vitro.

Methods:

Human liver carcinoma cell lines (HepG2 and SMMC-7721), a human non-small cell lung cancer cell line (A549), human osteosarcoma cell lines (MG63, U2OS, and KHOS), a human colon cancer cell line (HCT-116) and a human cervical cancer cell line (HeLa) were used. The anti-proliferative effects of the compounds were measured using SRB cytotoxicity assay. DNA damage was detected by immunofluorescence and Western blotting. Apoptosis and cell cycle distribution were assessed using flow cytometry analysis. The expression of the related proteins was examined with Western blotting analysis.

Results:

Both chamaejasmenin B and neochamaejasmin C exerted potent anti-proliferative effects in the 8 human solid tumor cell lines. Chamaejasmenin B (the IC₅₀ values ranged from 1.08 to 10.8 μmol/L) was slightly more potent than neochamaejasmin C (the IC₅₀ values ranged from 3.07 to 15.97 μmol/L). In the most sensitive A549 and KHOS cells, the mechanisms underlying the anti-proliferative effects were characterized. The two compounds induced prominent expression of the DNA damage marker γ-H2AX as well as apoptosis. Furthermore, treatment of the cells with the two compounds caused prominent G₀/G₁ phase arrest.

Conclusion:

Chamaejasmenin B and neochamaejasmin C are potential anti-proliferative agents in 8 human solid tumor cell lines in vitro via inducing cell cycle arrest, apoptosis and DNA damage.     

Amiloride sensitizes human pancreatic cancer cells to erlotinib in vitro through inhibition of the PI3K/AKT signaling pathway

Aim:

Blockade of EGFR by EGFR tyrosine kinase inhibitors such as erlotinib is insufficient for effective treatment of human pancreatic cancer due to independent activation of the Akt pathway, while amiloride, a potassium-sparing diuretic, has been found as a potential Akt inhibitor. The aim of this study was to investigate the anticancer effects of combined amiloride with erlotinib against human pancreatic cancer cells in vitro.

Methods:

Cell proliferation, colony formation, cell cycle and apoptosis were analyzed in 4 human pancreatic cancer cell lines Bxpc-3, PANC-1, Aspc-1 and CFPAC-1 treated with erlotinib or amiloride alone, or in their combination. The synergistic analysis for the effects of combinations of amiloride and erlotinib was performed using Chou-Talalay''s combination index isobolographic method.

Results:

Amiloride (10, 30, and 100 μmol/L) concentration-dependently potentiated erlotinib-induced inhibition of cell proliferation and colony formation in the 4 pancreatic cancer cell lines. Isobolographic analysis confirmed that combinations of amiloride and erlotinib produced synergistic cytotoxic effects. Amiloride significantly potentiated erlotinib-induced G₀/G₁ cell-cycle arrest and apoptosis in Bxpc-3 and PANC-1 cells. Amiloride inhibited EGF-stimulated phorsphorylation of AKT, and significantly enhanced erlotinib-induced downregulation of phorsphorylation of EGFR, AKT, PI3K P85 and GSK 3β in Bxpc-3 and PANC-1 cells.

Conclusion:

Amiloride sensitizes human pancreatic cancer cells to erlotinib in vitro through inhibition of the PI3K/AKT signaling pathway. Treatment of pancreatic cancer patients with combination of erlotinib and amiloride merits further investigation.     

Crotoxin induces apoptosis and autophagy in human lung carcinoma cells in vitro via activation of the p38MAPK signaling pathway

Aim:

Crotoxin (CrTX) is the primary toxin in South American rattlesnake (Crotalus durissus terrificus) venom, and exhibits antitumor and other pharmacological actions in vivo and in vitro. Here, we investigated the molecular mechanisms of the antitumor action of CrTX in human lung carcinoma cells in vitro.

Methods:

Human lung squamous carcinoma SK-MES-1 cells were tested. The cytotoxicity of CrTX was evaluated in both MTT and colony formation assays. Cell cycle was investigated with flow cytometry. Cell apoptosis was studied with Hoechst 33258 and Annexin V-FITC staining. The levels of relevant proteins were analyzed using Western blot assays.

Results:

CrTX (25, 50, 100 μmol/L) inhibited the growth and colony formation of SK-MES-1 cells in dose- and time-dependent manners. CrTX increased the proportion of S phase cells and dose-dependently induced cell apoptosis, accompanied by down-regulating the expression of proliferating cell nuclear antigen (PCNA), and increasing the level of cleaved caspase-3. Furthermore, CrTX dose-dependently increased the expression of autophagy-related proteins LC3-II and beclin 1, and decreased the level of p62 in the cells. Moreover, CrTX (50 μmol/L) significantly increased p38MAPK phosphorylation in the cells. Pretreatment of the cells with SB203580, a specific inhibitor of p38MAPK, blocked the inhibition of CrTX on cell proliferation, as well as CrTX-induced apoptosis and cleaved caspase-3 expression.

Conclusion:

The p38MAPK signaling pathway mediates CrTX-induced apoptosis and autophagy of human lung carcinoma SK-MES-1 cells in vitro.     

Atorvastatin inhibits homocysteine-induced dysfunction and apoptosis in endothelial progenitor cells

Aim:

To investigate the protective effects of atorvastatin on homocysteine (Hcy)-induced dysfunction and apoptosis in endothelial progenitor cells (EPCs) and the possible molecular mechanisms.

Methods:

EPCs were divided into six groups: Hcy treatment groups (0, 50, and 500 μmol/L) and atorvastatin pretreatment groups (0.1, 1, and 10 μmol/L). EPC proliferation, migration, in vitro vasculogenesis activity, and apoptosis rate were assayed by the MTT assay, modified Boyden chamber assay, in vitro vasculogenesis kit, and AnnexinV-FITC apoptosis detection kit, respectively. The level of reactive oxygen species (ROS) in cells was measured using H₂DCF-DA as a fluorescence probe. The activity of NADPH oxidase was evaluated with lucigenin-enhanced chemiluminescence. NO in the supernatant was detected by the nitrate reductase assay. The eNOS mRNA expression and p-eNOS, p-Akt, p-p38MAPK protein expression were measured by RT-PCR and Western blotting analysis, respectively. Caspase-3 activity was determined by colorimetric assay.

Results:

Hcy does-dependently impaired the proliferation, migration and in vitro vasculogenesis capacity of EPCs, induced cell apoptosis, increased ROS accumulation and NADPH oxidase activation, and decreased the secretion of NO compared with the control group (P<0.05 or P<0.01). The detrimental effects of Hcy were attenuated by atorvastatin pretreatment. Furthermore, Hcy caused a significant downregulation of eNOS mRNA, p-eNOS, and p-Akt protein expression as well as an upregulation of p-p38MAPK protein expression and caspase-3 activity. These effects of Hcy on EPCs were reversed by atorvastatin in a does-dependent manner.

Conclusion:

Atorvastatin inhibited homocysteine-induced dysfunction and apoptosis in endothelial progenitor cells, which may be related to its effects on suppressing oxidative stress, up-regulating Akt/eNOS and down-regulating the p38MAPK/caspase-3 signaling pathway.     

dentification of DW532 as a novel anti-tumor agent targeting both kinases and tubulin

Aim： 7,8-Dihydroxy-4-（3-hydroxy-4-methoxyphenyl）-2H-chromen-2-one （DW532） is one of simplified analogues of hematoxylin that has shown broad-spectrum inhibition on tyrosine kinases and in vitro anti-cancer activities. The aim of this study was to identify DW532 as a agent targeting both kinases and tubulin, and to investigate its anti-cancer and anti-angiogenesis activities. Methods： In vitro tyrosine kinases activity was examined with ELISA, and tyrosine kinases activity in cells was evaluated with Western blot analysis. Tubulin turbidity assay, surface plasmon resonance and immunofluorescence technique were used to characterize the tubulin inhibitory activity. Cell proliferation was examined with SRB assay, and cell apoptosis and cell cycle distribution were analyzed with Annexin-V/PI staining and flow cytometry. Tube formation, aortic ring and chick chorioallantoic membrane assays were used to evaluate the anti-angiogenesis efficacy. Results： DW532 inhibited EGFR and VEGFR2 in vitro kinase activity （the ICso values were 4.9 and 5.5 pmol/L, respectively）, and suppressed their downstream signaling. DW532 dose-dependently inhibited tubulin polymerization via direct binding to tubulin, thus disrupting the mitotic spindle assembly and leading to abnormal cell division. In a panel of human cancer cells, DW532 （1 and 10 pmol/L） induced G2/M phase arrest and cell apoptosis, which subsequently resulted in cytotoxicity. Knockdown of BubR1 or Mpsl, the two core proteins of the spindle assembly checkpoint dramatically decreased DW532-induced cell cycle arrest in MDA-MB-468 cells. Moreover, treatment with DW532 potently and dose-dependently suppressed angiogenesis in vitro and in vivo. Conclusion： DW532 is a dual inhibitor against tubulin and tyrosine kinases, and deserves further development as a novel anti-cancer agent.     

In vitro and in vivo antineoplastic activity of a novel bromopyrrole and its potential mechanism of action

Background and purpose:

Many bromopyrrole compounds have been reported to have in vitro antineoplastic activity. In a previous study, we isolated N-(4, 5-dibromo-pyrrole-2-carbonyl)-L-amino isovaleric acid methyl ester (B6) from marine sponges. Here, we investigated the in vitro and in vivo antineoplastic activity of B6 and its potential mechanism.

Experimental approach:

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the in vitro antineoplastic activity of B6. Flow cytometry, western blot analysis and morphological observations were used to investigate its mechanism of action. A mouse xenograft model was used to determine its in vivo activity.

Key results:

B6 inhibited the proliferation of various human cancer cells in vitro, with highest activity on LOVO and HeLa cells. B6 also exhibited significant growth inhibitory effects in vivo in a xenograft mouse model. Acute toxicity analysis suggested that B6 has low toxicity. B6-treated cells arrested in the G1 phase of the cell cycle and had an increased fraction of sub-G1 cells. In addition, the population of Annexin V-positive/propidium iodide-negative cells increased, indicating the induction of early apoptosis. Indeed, B6-treated cells exhibited morphologies typical of cells undergoing apoptosis. Western blotting showed cleaved forms of caspase-9 and caspase-3 in cells exposed to B6. Moreover, B6-promoted Ca²⁺ release and apoptosis was associated with elevated intracellular Ca²⁺concentration.

Conclusions and implications:

B6 has significant antineoplastic activity in vitro as well as in vivo. It inhibits tumour cell proliferation by arresting the cell cycle and inducing apoptosis. With its low toxicity, B6 represents a promising antineoplastic, primary compound.     

Betulinic acid inhibits endotoxin-stimulated phosphorylation cascade and pro-inflammatory prostaglandin E(2) production in human peripheral blood mononuclear cells

BACKGROUND AND PURPOSE

Betulinic acid (BA) is a naturally occurring triterpenoid widely distributed throughout the plant kingdom. We previously reported that BA inhibits lipopolysaccharide (LPS)-induced interleukin-6 production through modulation of nuclear factor κB (NF-κB) in human peripheral blood mononuclear cells (hPBMCs). This study attempted to identify other mechanisms through which BA modulates LPS signalling in mononuclear cells. The effects of BA on signalling pathways downstream were focused on in this study.

EXPERIMENTAL APPROACH

We determined the ability of BA to interfere with p38 and extracellular regulated kinase (ERK) phosphorylation as well as Akt phosphorylation and nuclear factor-κB activation using LPS-activated hPBMCs as an in vitro model. LPS-induced endotoxin shock in mice was the in vivo model employed.

KEY RESULTS

BA inhibited LPS-induced COX-2 protein expression and prostaglandin E₂ production and also attenuated LPS-induced ERK and Akt phosphorylation, but not p38 in hPBMCs. BA abolished LPS-induced IκBα phosphorylation and thus normalized the levels of IκBα in cytosol. BA also inhibited LPS-induced reactive oxygen species formation and lactate dehydrogenase release. Interestingly, BA improved the life span of mice in endotoxin shock and also inhibited PGE₂ production and myeloperoxidase activity in vivo.

CONCLUSIONS AND IMPLICATIONS

BA modulates LPS-induced COX-2 expression in hPBMCs by inhibiting ERK and Akt pathways as well as by modulating IκBα phosphorylation. At the same time, no cell toxicity was observed. The effect of the drug was confirmed through in vivo experiments. The study gives an insight into the molecular mechanisms of BA.     

Cathepsin L suppression increases the radiosensitivity of human glioma U251 cells via G2/M cell cycle arrest and DNA damage

Aim:

Cathepsin L is a lysosomal cysteine protease that plays important roles in cancer tumorigenesis, proliferation and chemotherapy resistance. The aim of this study was to determine how cathepsin L regulated the radiosensitivity of human glioma cells in vitro.

Methods:

Human glioma U251 cells (harboring the mutant type p53 gene) and U87 cells (harboring the wide type p53 gene) were irradiated with X-rays. The expression of cathepsin L was analyzed using Western blot and immunofluorescence assays. Cell survival and DNA damage were evaluated using clonogenic and comet assays, respectively. Flow cytometry was used to detect the cell cycle distribution. Apoptotic cells were observed using Hoechst 33258 staining and fluorescence microscopy.

Results:

Irradiation significantly increased the cytoplasmic and nuclear levels of cathepsin L in U251 cells but not in U87 cells. Treatment with the specific cathepsin L inhibitor Z-FY-CHO (10 μmol/L) or transfection with cathepsin L shRNA significantly increased the radiosensitivity of U251 cells. Both suppression and knockdown of cathepsin L in U251 cells increased irradiation-induced DNA damage and G₂/M phase cell cycle arrest. Both suppression and knockdown of cathepsin L in U251 cells also increased irradiation-induced apoptosis, as shown by the increased levels of Bax and decreased levels of Bcl-2.

Conclusion:

Cathepsin L is involved in modulation of radiosensitivity in human glioma U251 cells (harboring the mutant type p53 gene) in vitro.     

WTC-01, a novel synthetic oxime-flavone compound,destabilizes microtubules in human nasopharyngeal carcinoma cells in vitro and in vivo

Background and Purpose

Dynamic polymerization of microtubules is essential for cancer cell growth and metastasis, and microtubule-disrupting agents have become the most successful anti-cancer agents in clinical use. Besides their antioxidant properties, flavonoids also exhibit strong microtubule-disrupting activity and inhibit tumour growth. We have designed, synthesized and tested a series of oxime/amide-containing flavone derivatives. Here we report the evaluation of one compound, WTC-01 for its anti-proliferative effects in human cancer cells.

Experimental approach

We used a range of cancer cell lines including two human nasopharyngeal carcinoma (NPC) cell lines, measuring proliferation, cell cycle and apoptosis, along with caspase levels and mitochondrial membrane potentials. Assays of tubulin polymerisation in vitro and computer modelling of the colchicine binding site in tubulin were also used. In mice, pharmacokinetics and growth of NPC-derived tumours were studied.

Key Results

WTC-01 was most potent against proliferation of NPC cells (IC₅₀ = 0.45 μM), inducing accumulation of cells in G₂/M and increasing apoptosis, time- and concentration-dependently. The colchicine competition-binding experiments and computer modelling results suggested that WTC-01 causes microtubule disruption via binding to the colchicine-binding site of tubulin resulting in mitochondrial membrane damage and cell apoptosis via activation of caspase-9/-3 without noticeable activation of the caspase-8. Notably, our in vivo studies demonstrated that at doses of 25 and 50 mg·kg⁻¹, WTC-01 exhibited good pharmacokinetic properties and completely inhibited the growth of NPC-TW01 cells in a xenograft nude mouse model.

Conclusions and Implications

WTC-01, a new synthetic oxime-containing flavone, exhibited potent anti-tumour activity against NPC cells and merits further investigation.     

Fructus phyllanthi tannin fraction induces apoptosis and inhibits migration and invasion of human lung squamous carcinoma cells in vitro via MAPK/MMP pathways

Aim:

Fructus phyllanthi tannin fraction (PTF) from the traditional Tibetan medicine Fructus phyllanthi has been found to inhibit lung and liver carcinoma in mice. In this study we investigated the anticancer mechanisms of PTF in human lung squamous carcinoma cells in vitro.

Methods:

Human lung squamous carcinoma cell line (NCI-H1703), human large-cell lung cancer cell line (NCI-H460), human lung adenocarcinoma cell line (A549) and human fibrosarcoma cell line (HT1080) were tested. Cell viability was detected with MTT assay. Cell migration and invasion were assessed using a wound healing assay and a transwell chemotaxis chambers assay, respectively. Cell apoptosis was analyzed with flow cytometric analysis. The levels of apoptosis-related and metastasis-related proteins were detected by Western blot and immunofluorescence.

Results:

PTF dose-dependently inhibited the viability of the 3 human lung cancer cells. The IC₅₀ values of PTF in inhibition of NCI-H1703, NCI-H460, and A549 cells were 33, 203, and 94 mg/L, respectively. PTF (15, 30, and 60 mg/L) dose-dependently induced apoptosis of NCI-H1703 cells. Treatment of NCI-H1703 and HT1080 cells with PTF significantly inhibited cell migration, and reduced the number of invasive cells through Matrigel. Furthermore, PTF dose-dependently down-regulated the expression of phosphor-ERK1/2, MMP-2 and MMP-9, up-regulated the expression of phosphor-JNK, but had no significant effect on the expression of ERK1/2 or JNK.

Conclusion:

PTF induces cell apoptosis and inhibits the migration and invasion of NCI-H1703 cells by decreasing MPPs expression through regulation of the MAPK pathway.     

New benzimidazole acridine derivative induces human colon cancer cell apoptosis in vitro via the ROS-JNK signaling pathway

Aim:

To investigate the mechanisms underlying anticancer action of the benzimidazole acridine derivative N-{(1H-benzo[d]imidazol-2-yl)methyl}-2-butylacridin-9-amine(8m) against human colon cancer cells in vitro.

Methods:

Human colon cancer cell lines SW480 and HCT116 were incubated in the presence of 8m, and then the cell proliferation and apoptosis were measured. The expression of apoptotic/signaling genes and proteins was detected using RT-PCR and Western blotting. ROS generation and mitochondrial membrane depolarization were visualized with fluorescence microscopy.

Results:

8m dose-dependently suppressed the proliferation of SW480 and HCT116 cells with IC50 values of 6.77 and 3.33 μmol/L, respectively. 8m induced apoptosis of HCT116 cells, accompanied by down-regulation of Bcl-2, up-regulation of death receptor-5 (DR5), truncation of Bid, cleavage of PARP, and activation of caspases (including caspase-8 and caspase-9 as well as the downstream caspases-3 and caspase-7). Moreover, 8m selectively activated JNK and p38 without affecting ERK in HCT116 cells. Knockout of JNK1, but not p38, attenuated 8m-induced apoptosis. In addition, 8m induced ROS production and mitochondrial membrane depolarization in HCT116 cells. Pretreatment with the antioxidants N-acetyl cysteine or glutathione attenuated 8m-induced apoptosis and JNK activation in HCT116 cells.

Conclusion:

The new benzimidazole acridine derivative, 8m exerts anticancer activity against human colon cancer cells in vitro by inducing both intrinsic and extrinsic apoptosis pathways via the ROS-JNK1 pathway.     

Effects of triptolide on RIZ1 expression, proliferation, and apoptosis in multiple myeloma U266 cells

Aim:

To investigate the effects of triptolide on proliferation and apoptosis as well as on the expression of RIZ1 in the human multiple myeloma cell line U266 in vitro.

Methods:

The effect of triptolide on the growth of U266 cells was studied by MTT assay. Apoptosis was detected by Hoechst 33258 staining and Annexin V/PI double-labeled flow cytometry, and caspase-3 mRNA was measured by RT-PCR. Western blotting, flow cytometry and RT-PCR were used to assess the expression of RIZ1, and the location and expression of H3K9me1 were detected by confocal microscopy and Western blotting.

Results:

Triptolide significantly inhibited the proliferation of U266 cells in a time- and concentration-dependent manner (the IC₅₀ value for a 24-h exposure was 157.19±0.38 nmol/L). Triptolide induced typical apoptotic morphological changes. Triptolide 40, 80, and 160 nmol/L treatment induced significant caspase-3-dependent apoptosis compared with control group (10.5%±1.23%, 37.9%±2.45%, and 40.5%±2.30% vs 3.8%±1.98%, P<0.05). Compared with peripheral blood monocular cells (PBMC) from healthy donors, the protein expression of RIZ1 in U266 cells was relatively low, but the mRNA and protein expression of RIZ1 were strikingly increased by triptolide in a concentration-dependent manner. Triptolide increased the protein expression of RIZ1 and RIZ1 methylates histone H3 lysine 9 in U266 cells.

Conclusion:

Triptolide increased the protein expression of RIZ1, inhibited the proliferation, and induced caspase-dependent apoptosis in U266 cells.     

N-Propionyl polysialic acid precursor enhances the susceptibility of multiple myeloma to antitumor effect of anti-NprPSA monoclonal antibody

Aim:

To study the antitumor effect of anti-NprPSA monoclonal antibody (mAb) in combination with ManNPr, a precursor of N-propionyl PSA, in multiple myeloma (MM), and to explore the mechanisms of the action.

Methods:

Human multiple myeloma cell line RPMI-8226 was tested. The cells were pre-treated with ManNPr (1, 2, and 4 mg/mL), and then incubated with anti-NprPSA mAb (1 mg/mL). Cell apoptosis in vitro was detected using MTT assay and flow cytometry. BALB/c nude mice were inoculated sc with RPC5.4 cells. On 5 d after the injection, the mice were administered sc with anti-NprPSA mAb (200 μg/d) and ManNPr (5 mg/d) for 8 d. The tumor size and body weight were monitored twice per week. TUNEL assay was used for detecting apoptosis in vivo. The apoptotic pathway involved was examined using Western blot analysis and caspase inhibitor.

Results:

Treatment of RPMI-8226 cells with anti-NprPSA mAb alone failed to inhibit cell growth in vitro. In RPMI-8226 cells pretreated with ManNPr, however, the mAb significantly inhibited the cell proliferation, decreased the viability, and induced apoptosis, which was associated with cleavage of caspase-3, caspase-8, caspase-9, and poly(ADP-ribose) polymerase. In the mouse xenograft model, treatment with the mAb in combination with ManNPr significantly inhibited the tumor growth, and induced significant apoptosis as compared to treatment with the mAb alone. Moreover, apoptosis induced by the mAb in vivo resulted from the activation of the caspases and poly(ADP-ribose) polymerase.

Conclusion:

The anti-NprPSA mAb in combination with ManNPr is an effective treatment for in vitro and in vivo induction of apoptosis in multiple myeloma.     

Drug packaging and delivery using perfluorocarbon nanoparticles for targeted inhibition of vascular smooth muscle cells

Aim:

To investigate the in vitro release profile of drugs encapsulated within perfluorocarbon (PFC) nanoparticles (NPs) and their ability to inhibit the activity of vascular smooth muscle cells (SMCs).

Methods:

Dexamethasone phosphate (DxP) or dexamethasone acetate (DxA) was encapsulated into PFC nanoparticles using a high-pressure homogenous method. The morphology and size of the NPs were examined using scanning electron microscopy (SEM) and a laser particle size analyzer. Drug loading and in vitro release were assessed by high-performance liquid chromatography (HPLC). The impact of NP capsules on SMC proliferation, migration and apoptosis in vitro was assessed using cell counting kit-8, transwell cell migration and flow cytometry assays.

Results:

The sizes of DxP-NPs and DxA-NPs were 224±6 nm and 236±9 nm, respectively. The encapsulation efficiency (EE) of DxP-NPs was 66.4%±1.0%, with an initial release rate of 77.2%, whereas the EE of DxA-NPs was 95.3%±1.3%, with an initial release rate of 23.6%. Both of the NP-coated drugs could be released over 7 d. Human umbilical artery SMCs were harvested and cultured for four to six passages. Compared to free DxP, SMCs treated with tissue factor (TF)-directed DxP-NPs showed significant differences in the inhibition of proliferation, migration and apoptosis (P<0.05).

Conclusion:

The results collectively suggest that PFC nanoparticles will be beneficial for targeted drug delivery because of the sustained drug release and effective inhibition of SMC proliferation and migration.     

Association between BclI polymorphism in the NR3C1 gene and in vitro individual variations in lymphocyte responses to methylprednisolone

AIM

To evaluate the association between the in vitro sensitivity of peripheral blood mononuclear cells (PBMCs) to methylprednisolone (MP) and the presence of genetic polymorphisms involved in glucocorticoid (GC) response.

METHODS

In vitro MP inhibition of the proliferation of lymphocytes stimulated with concanavalin A was determined. Non linear regression of dose–response data was performed computing the MP concentration required to reduce proliferation to 50% (IC₅₀). The maximum inhibition achievable at the highest MP concentration (I_max) was also calculated. Moreover, the Taqman technique was used to analyze the BclI polymorphism in the NR3C1 gene and the Leu155His polymorphism in the NALP1 gene.

RESULTS

A significant association between the BclI mutated genotype and an increased in vitro sensitivity to GCs was observed.

CONCLUSIONS

The a priori evaluation of the BclI polymorphism, associated with a lymphocyte proliferation assay, could represent a useful diagnostic tool for the optimization of steroid treatment.     

RIP3 overexpression sensitizes human breast cancer cells to parthenolide in vitro via intracellular ROS accumulation

Aim： Receptor-interacting protein 3 （RIP3） is involved in tumor necrosis factor receptor signaling, and results in NF-KB-mediated prosurvival signaling and programmed cell death. The aim of this study was to determine whether overexpression of the RIP3 gene could sensitize human breast cancer cells to parthenolide in vitro. Methods： The expression of RIP3 mRNA in human breast cancer cell lines （MCF-7, MDA-MB-231, MDA-MB-435 and T47D） was detected using RT-PCR. Both MDA-MB-231 and MCF-7 cells were transfected with RIP3 expression or blank vectors via lentivirus. Cell viability was measured with MTT assay; intracellular ROS level and cell apoptosis were analyzed using flow cytometry. Results： RIP3 mRNA expression was not detected in the four human breast cancer cell lines tested. However, the transfection induced higher levels of RIP3 protein in MCF-7 and MDA-MB-231 cells. Furthermore, overexpression of RIP3 decreased the IC50 values of parthenolide from 17.6 to 12.6 μmol/L in MCF-7 cells, and from 16.6 to 9.9 μmol/L in MDA-MB-231 cells. Moreover, overexpression of RIP3 significantly increased parthenolide-induced apoptosis and ROS accumulation in MCF-7 and MDA-MB-231 cells. Pretreatment with N-acetyl-cysteine abrogated the increased sensitivity of RIP3-transfected MCF-7 and MDA-MB-231 cells to parthenolide. Conclusion： Overexpression of RIP3 sensitizes MCF-7 and MDA-MB-231 breast cancer cells to parthenolide in vitro via intracellular ROS accumulation.