[Qianliexin Capsules for carrageenin-induced chronic nonbacterial prostatitis: A metabolomics study].

OBJECTIVE: To explore the regulating mechanism of the Chinese medicinal compound Qianliexin Capsules (QLX) in the treatment of chronic nonbacterial prostatitis (CNP). METHODS: We randomly divided 18 SPF SD male rats into a normal control (n = 6), a model control (n = 6) and a QLX group (n = 6). After successful establishment of a CNP model in the latter two groups by injecting 50 µl 1% carrageenan bilaterally into the prostate, we treated the rats in the QLX group by intragastrical administration of QLX at 4 g/kg, tid, and those in the normal and model control groups with the same volume of pure water, all for 45 days. Then, we examined the possible lower urinary tract symptoms (LUTS) of CNP by detecting the prostate indexes, expression of the tissue inflammatory factor IL-1 ß, 24-hour urine volume and pain threshold reaction (PTR) time, and conducted a metabonomics analysis of the urine and plasma samples. RESULTS: Compared with the normal controls, the CNP model rats showed dramatically increased prostate coefficient (ï¼»0.75 ± 0.09ï¼½ ‰ vs ï¼»1.60 ± 0.35ï¼½ ‰, P < 0.01) and the expression of IL-1ß (ï¼»22.61 ± 2.77ï¼½ vs ï¼»55.12 ± 4.94ï¼½ ng/ml, P < 0.01), which were both decreased in the QLX group (ï¼»0.97 ± 0.10ï¼½ ‰ and ï¼»36.64 ± 7.25ï¼½ ng/ml) in comparison with those in the model controls (P < 0.01). The urine volume was remarkably reduced in the model control group compared with that in the normal controls (4 ml vs 16.38 ml, P < 0.01), and so was the PTR time (ï¼»13.83 ± 5.67ï¼½ vs ï¼»23.73 ± 2.52ï¼½ s, P < 0.01), while the levels of urea nitrogen (ï¼»23.06 ± 3.71ï¼½ vs ï¼»17.92 ± 1.41ï¼½ mg/dL, P < 0.01), creatinine (ï¼»48.08 ± 9.31ï¼½ vs ï¼»40.31 ± 3.53ï¼½ µmol/L, P < 0.01) and uric acid (ï¼»181.36 ± 64.06ï¼½ vs ï¼»84.33 ± 21.40ï¼½ µmol/L, P < 0.01) increased significantly. The animals in the QLX group exhibited significant improvement in the urine volume (ï¼»13.44 ± 2.26ï¼½ ml), PTR time (ï¼»31.45 ± 2.96ï¼½ s), urea nitrogen (ï¼»16.49 ± 1.86ï¼½ mg/dL), creatinine (ï¼»36.88 ± 7.98ï¼½ µmol/L) and uric acid (ï¼»117.47 ± 40.09ï¼½ µmol/L) in comparison with the model controls (P < 0.01). Metabonomics analysis revealed a reversing effect of QLX on the carrageenin-induced alteration in a variety of metabolites in the urine and serum, restoring the ratios of such metabolites as glycine, cysteine, ketoimine quinolinic acid, aminobutyraldehyde and triphosphate to almost normal. Pathway enrichment analysis showed that the main metabolic pathways were aspartate and glutamate pathways. The ratios of such metabolites as neuroside, adipic acid, diacylglycerol, choline lecithin and so on in the plasma sample were dramatically improved in the QLX group compared with those in the model controls (P < 0.01). CONCLUSION: QLX significantly improves the symptoms of CNP and has a definite effect on amino acids, phosphatidyl and other biomarkers through the tricarboxylic acid cycle, amino acid metabolism, lipid metabolism and other related pathways.

Enhancement of Dissolving Capacity and Reducing Gastric Mucosa Irritation by Complex Formation of Resibufogenin with ß-Cyclodextrin or 2-Hydroxypropyl-ß-cyclodextrin.

Resibufogenin (RBG) is a natural medicinal ingredient with promising cardiac protection and antitumor activity. However, poor solubility and severe gastric mucosa irritation restrict its application in the pharmaceutical field. In this study, the inclusion complex of RBG with ß-cyclodextrin (ß-CD) and 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) was prepared using the co-evaporation method, and the molar ratio of RBG to CD was determined to be approximately 1:2 by continuous variation plot for both CDs. The formation of inclusion complexes between RBG and each CD (RBG/ß-CD and RBG/HP-ß-CD) was evaluated by phase solubility study, Fourier transform infrared spectroscopy, and thin-layer chromatography. Powder X-ray diffraction and differential scanning calorimetry confirmed drug amorphization and encapsulation in the molecular cage for both CDs. Moreover, the inclusion complexes' morphologies were observed using scanning electron microscopy. The dissolution rate of the inclusion complexes was markedly improved compared to that of RBG, and the complexes retained their antitumor activity, as shown in the in vitro cytotoxicity assay on a human lung adenocarcinoma cancer (A549) cell line. Moreover, less gastric mucosal irritation was observed for the inclusion complex. Thus, the inclusion complex should be considered a promising strategy for the delivery of poorly water-soluble anticancer agents, such as RBG.

Qianliexin capsule exerts anti-inflammatory activity in chronic non-bacterial prostatitis and benign prostatic hyperplasia via NF-κB and inflammasome.

Qianliexin capsule (QLX) is a standardized traditional Chinese herbal preparation that has long been used to treat chronic non-bacterial prostatitis (CNP) and benign prostatic hyperplasia (BPH). This study investigated the anti-inflammatory activity of QLX in improving lower urinary tract symptoms (LUTS) associated with CNP and BPH. Rat models of CNP and BPH were induced by oestradiol or testosterone (hormonal imbalance) or chemical inflammation (carrageenan). QLX significantly relieved LUTS in CNP and BPH rat model by reducing prostate enlargement, epithelial thickness, pain response time, urine volume and bleeding time, and by improving prostatic blood flow. The expression of the pro-inflammatory cytokines interleukin (IL)-1ß and tumour necrosis factor (TNF)-α, the pro-inflammatory transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and inflammasome components (NLRP3, caspase-1 and ASC) in CNP and BPH tissues was reduced by QLX addition. QLX treatment was followed by reduced cellular malondialdehyde and increased superoxide dismutase, catalase and glutathione peroxidase activity, consistent with antioxidant activity. Increases in Beclin-1 expression and the LC3II/I ratio following QLX treatment indicated that autophagy had been induced. QLX relieved LUTS in CNP and BPH rat models by inhibiting inflammation. The underlying mechanisms included inhibition of inflammasome activation, NF-κB activation, oxidant stress and autophagy.

A metabolomics study of Qianliexin capsule treatment of benign prostatic hyperplasia induced by testosterone propionate in the rat model.

A metabolomics investigation of the treatment effect of Qianliexin (QLX) capsules was conducted on rats with benign prostatic hyperplasia (BPH) induced by testosterone propionate. Establishment of the BPH model was confirmed using the prostatic index. Hematoxylin and eosin (HE) staining for TGF-ß, EGFR, collagen, IL-1 ß, TNF-α was performed and changes in urine volume were measured. Urine and serum samples were collected from three groups, including a control group, a BPH model group and a QLX-treated group and subjected to metabolomics profiling based on ultrahigh-performance liquid chromatography-mass spectrometry. Pharmacodynamics analysis showed that the QLX group had significantly lower histopathological damage, fibrosis damage, and inflammation and higher urine output compared with the model group. Twenty-two potential biomarkers were identified in urine samples and 23 metabolites were identified in plasma samples. Alterations in metabolic patterns were evident in all sample types. The treatment effects of QLX appear to involve various metabolic pathways including lipid metabolism, fatty acid metabolism and purine generation and significantly reduced the pathological symptoms and related biochemical indicators of BPH and improved the level of potential marker metabolites. This comprehensive study suggested that differential markers provided insights into the metabolic pathways involved in BPH and the treatment effects of QLX.

Antiproliferative chromone derivatives induce K562 cell death through endogenous and exogenous pathways.

A series of furoxan derivatives of chromone were prepared. The antiproliferative activities were tested against five cancer cell lines HepG2, MCF-7, HCT-116, B16, and K562, and two normal human cell lines L-02 and PBMCs. Among them, compound 15a exhibited the most potent antiproliferative activity. It was also found 15a produced more than 8 µM of NO at the peak time of 45 min by Griess assay. Generally, antiproliferative activity is positively related to NO release to some extent. Further in-depth studies on apoptosis-related mechanisms showed that 15a caused S-phase cell cycle arrest in a concentration-dependent manner and induced apoptosis significantly through mitochondria-related pathways. Human apoptosis protein array assay also demonstrated 15a increased the expression levels of pro-apoptotic Bax, Bad, HtrA2 and Trail R2/DR5. The expression of catalase and cell cycle blocker claspin were similarly up-regulated. In balance, 15a induced K562 cells death through both endogenous and exogenous pathways.

Design, synthesis and anti-inflammatory evaluation of novel pyrrolo[2,3-d]pyrimidin derivatives as potent JAK inhibitors.

Aiming to develop potent JAK inhibitors, two series of 4-(1H-pyrazol-4-yl)-7H-pyrrolo[2,3-d]pyrimidine derivatives (8a-8p and 11a-11i) were designed and synthesized by coalescing various N-acylpiperidine motifs with baricitinib. The pharmacological results based on enzymatic and cellular assays identified the optimized compound 11e, which exerted over 90% inhibition rates against JAK1 and JAK2, and displayed the most compelling anti-inflammatory efficacy superior to baricitinib by inhibiting NO generation from LPS-induced RAW264.7 macrophages. Importantly, low cytotoxity of 11e was revealed by the IC50 value of 88.2 µM against normal RAW264.7 cells. The binding mode of 11e with JAK1 and JAK2 identified the essential structural bases in accord with SARs analysis. Furthermore, cellular morphology observation and western blot analysis disclosed the ability of 11e to relieve cells inflammatory damage by significantly down-regulating LPS-induced high expression of JAK1, JAK2, as well as pro cytokine IL-1ß. Together, 11e was verified as a promising lead for JAK inhibitors for the treatment of inflammatory diseases.

ERß up-regulation was involved in silibinin-induced growth inhibition of human breast cancer MCF-7 cells.

We previously reported that silibinin induced a loss of cell viability in breast cancer (MCF-7) cells by ERα down-regulation. But whether this cytotoxicity depends on another estrogen receptor, ERß, has yet to be elucidated. Therefore, we sought to explore the effects of ERß modulation on cell viability by using an ERß-selective agonist (Diarylprepionitrile, DPN) and an antagonist (PHTPP). Our data demonstrated that ERß served as a growth suppressor in MCF-7 cells, and the incubation of silibinin, elevated ERß expression, resulting in the tumor growth inhibition. The cytotoxic effect of silibinin was diminished by PHTPP and enhanced by DPN. Silencing of ERß by siRNA confirmed these results. Apoptotic cascades, including the sequential activation of caspase-9 and -6, and finally the cleavage of caspase substrates, PARP and ICAD, caused by treatment with silibinin, were all repressed by PHTPP pre-treatment but exacerbated by DPN. Unlike ERα, ERß did not involve autophagic process in the regulation, since neither autophagic inhibitor (3-MA) nor the inducer (rapamycin) affected the cell survival rates regardless ERß activity. Taken together, silibinin induced apoptosis through mitochondrial pathway by up-regulating ERß pathways in MCF-7 cells without the involvement of autophagy.

Silibinin negatively contributes to primary cilia length via autophagy regulated by histone deacetylase 6 in confluent mouse embryo fibroblast 3T3-L1 cells.

Primary cilium is a cellular antenna, signalling as a sensory organelle. Numerous pathological manifestation is associated with change of its length. Although the interaction between autophagy and primary cilia has been suggested, the role of autophagy in primary cilia length is largely unknown. In this study the primary cilia were immunostained and observed by using confocal fluorescence microscopy, and we found that silibinin, a natural flavonoid, shortened the length of primary cilia, meanwhile it also induced autophagy in 3T3-L1 cells. This study was designed to investigate the significance of silibinin-induced autophagy in primary ciliary structure in confluent mouse embryo fibroblast 3T3-L1 cells. Either blocking the autophagic flux with pre-treatment with the autophagy inhibitor, 3-methyladenine (3-MA), or transfection of siRNA targeting LC3 inhibited the reduction of cilia length caused by silibinin exposure. Autophagy induced by silibinin decreased expressions of the cilia-associated proteins, such as IFT88, KIF3a and Ac-tubulin, while 3-MA restored it, indicating that autophagy induced by silibinin led to a reduction of primary cilia length. Histone deacetylase 6 (HDAC6), which was suggested as a mediator of autophagy, was up-regulated by silibinin in a time-dependent manner. In addition, 3T3-L1 cells treated with siRNA against HDAC6 had a reduced autophagic level and were protected from silibinin-induced cilia shortening. Taken together, we conclude that the HDAC6-mediated autophagy negatively regulates primary cilia length during silibinin treatment and has the potential to serve as a therapeutic target for primary cilia-associated ciliopathies. These findings thus provide new information about the potential link between autophagy and primary cilia.

ERα down-regulation plays a key role in silibinin-induced autophagy and apoptosis in human breast cancer MCF-7 cells.

The estrogen receptor alpha (ERα) has been proven to be one of the most important therapeutic targets in breast cancer over the last 30 years. Previous studies pointed out that a natural flavonoid, silibinin, induced apoptosis in human breast cancer MCF-7 cells. In the present study we report that exposure of MCF-7 cells to silibinin led to cell death through the down-regulation of ERα expression. Silibinin-induced apoptosis of MCF-7 cells through up-regulation of caspase 6 due to ERα signalling repression was further boosted by ERα antagonist. Moreover, up-regulation of autophagy induced by silibinin accounted for apoptotic exacerbation, being further enhanced by ERα inhibition. Upon ERα activation, series of downstream signalling pathways can be activated. We found that silibinin reduced the expressions of Akt/mTOR and extracellular-signal-related kinase (ERK), which respectively accounted for the induction of autophagy and apoptosis. These effects were further augmented by co-treatment with ERα inhibitor. We conclude that the treatment with silibinin of ERα-positive MCF-7 cells down-regulates the expression of ERα, and subsequently mTOR and ERK signaling pathways, ERα downstream, finally resulting in induction of autophagy and apoptosis.

Carbon quantum dots(CQDs)-sensitized CdS/CuInS2 heterojunction as a photoelectrochemical biosensing platform for highly sensitive detection of prostate-specific antigen.

Sensitive and quantitative detection of prostate-specific antigen (PSA) has been determined to be indispensable for clinical diagnostics of prostate cancer, whereas such detection is quite challenging due to the extremely low concentration of biomarkers in human serum samples. In this study, a photoelectrochemical (PEC) sensor was effectively developed for the high-sensitivity analysis of prostate-specific antigen (PSA) using a signal amplification method utilizing sensitized carbon quantum dots (CQDs). In this experiment, cadmium sulfide quantum dots were employed as the substrate materials, and indium copper sulfide quantum dots were loaded on their surfaces. Moreover, the efficient matching of energy levels in these two materials contributed to the generation of photocurrents. The aforementioned heterojunction semiconductor QDs were thus combined with CQDs to produce CQDs on their surfaces. As a result of the presence of CQDs, the ability of heterojunction materials to absorb light was remarkably enhanced, increasing the photocurrent by over ten times. Consequently, in this study, CQDs were combined with PEC sensors, and the developed PEC biosensors exhibited excellent optical performance, sensitivity, repeatability, and stability. The results obtained from the analysis of actual samples were satisfactory and have promising application prospects.

Interference of silibinin with IGF-1R signalling pathways protects human epidermoid carcinoma A431 cells from UVB-induced apoptosis.

Ultraviolet B (UVB) from sunlight is a major cause of cutaneous lesion. Silibinin, a traditional hepatic protectant, elicits protective effects against UVB-induced cellular damage. In A431 cells, the insulin-like growth factor-1 receptor (IGF-1R) was markedly up-regulated by UVB irradiation. The activation of the IGF-1R signalling pathways contributed to apoptosis of the cells rather than rescuing the cells from death. Up-regulated IGF-1R stimulated downstream mitogen-activated protein kinases (MAPKs), such as c-Jun N-terminal kinases (JNK) and extracellular signal-regulated protein kinases 1/2 (ERK1/2). The subsequent activation of caspase-8 and caspase-3 led to apoptosis. The activation of IGF-1R signalling pathways is the cause of A431 cell death. The pharmacological inhibitors and the small interfering RNA (siRNA) targeting IGF-1R suppressed the downstream activation of JNK/ERK-caspases to help the survival of the UVB-irradiated A431 cells. Indeed, silibinin treatment suppressed the IGF-1R-JNK/ERK pathways and thus protected the cells from UVB-induced apoptosis.

Physalin A induces apoptotic cell death and protective autophagy in HT1080 human fibrosarcoma cells.

Physalin A (1) is a withanolide isolated from Physalis alkekengi var. franchetii. In this study, the selective growth inhibitory effects on tumor cells induced by 1 were screened, and the mechanism was investigated on 1-induced growth inhibition, including apoptosis and autophagy, in human fibrosarcoma HT1080 cells. Apoptosis induced by 1 in HT1080 cells was associated with up-regulation of caspase-3 and caspase-8 expression. However, there were no significant changes in caspase-9, Bid, Bax, and Bcl-2 expression, indicating that 1-induced apoptosis in HT1080 cells occurs mainly through activation of the death receptor-associated extrinsic apoptotic pathways. Autophagy induced by 1 was found to antagonize apoptosis in HT1080 cells. This effect was enhanced by rapamycin and suppressed by the autophagy inhibitor 3-methyladenine (3MA). Loss of beclin 1 (as an autophagic regulator) function led to similar results to 3MA. However, 1 did not show inhibitory effects on normal human cells (human peripheral blood mononuclear cells). Taken together, these results suggest that 1 may be a promising agent for the treatment of cancer.

Preparation of trans-Crocetin with High Solubility, Stability, and Oral Bioavailability by Incorporation into Three Types of Cyclodextrins.

Crocetin (CRT), an active compound isolated from saffron, exhibits several pharmacological activities, including anti-tumor and immune-regulatory activities, and is effective against myocardial ischemia and coronary heart disease; however, its low stability and solubility limit its clinical application. Therefore, we investigated CRT inclusion complexes (ICs) with three cyclodextrins-α-CD, HP-ß-CD, and γ-CD-suitable for oral administration prepared using an ultrasonic method. Fourier transform infrared spectroscopy and powder X-ray diffraction indicated that the crystalline state of CRT in ICs disappeared, and intermolecular interactions were observed between CRT and CDs. 1H nuclear magnetic resonance and phase solubility studies confirmed CRT encapsulation in the CD cavity and the formation of ICs. In addition, we observed the morphology of ICs using scanning electron microscopy. All ICs showed a high drug encapsulation efficiency (approximately 90%) with 6500-10,000 times better solubilities than those of the pure drug. CRT showed rapid dissolution, whereas pure CRT was water-insoluble. The formation of ICs significantly improved the storage stability of CRT under heat, light, and moisture conditions. Further, the peak time of CRT in rats significantly decreased, and the relative bioavailability increased by approximately 3-4 times. In addition, the oral bioavailability of CRT IC was evaluated. Notably, the absorption rate and degree of the drug in rats were improved. This study illustrated the potential applications of CRT/CD ICs in the food, healthcare, and pharmaceutical industries, owing to their favorable dissolution, solubility, stability, and oral bioavailability.

Autophagy enhanced phagocytosis of apoptotic cells by oridonin-treated human histocytic lymphoma U937 cells.

Macrophages rapidly engulf and remove apoptotic cells to limit the release of noxious cellular contents and to restrict autoimmune disease or inflammation. Recent developments reveal an important role in autophagy for clearance of apoptotic corpses. However, the relationship between autophagy and phagocytosis remains unclear. In this study we found that low doses of oridonin, an active diterpenoid, enhanced phagocytosis of apoptotic cells by human macrophage-like U937 cells, meanwhile it also induced autophagy in these U937 cells. Moreover, inhibition of extracellular signal-related kinase (ERK), nuclear factor-κB (NF-κB) and caspase-1 significantly suppressed oridonin-induced phagocytosis and autophagy. In addition, oridonin increased the protein levels of p-ERK, NF-κB, caspase-1 and pro IL-1ß. Autophagic inhibitor 3-methyladenine (3-MA) decreased phagocytosis and the expression of ERK whereas increased the expression of NF-κB- and caspase-1-mediated IL-1ß release. Beclin-1 (known as autophagic regulator) loss also led to the similar results. Pretreatment with autophagic agonist rapamycin caused opposite results. Autophagy-associated proteins, Beclin-1, LC3 and Atg4B, involved in this phagocytosis process. These results demonstrated that autophagy enhanced oridonin-induced phagocytosis through feedback regulation of ERK, NF-κB- and caspase-1-mediated IL-1ß release.

Recent Progress of Oridonin and Its Derivatives for the Treatment of Acute Myelogenous Leukemia.

First stage human clinical trial (CTR20150246) for HAO472, the L-alanine-(14-oridonin) ester trifluoroacetate, was conducted by a Chinese company, Hengrui Medicine Co. Ltd, to develop a new treatment for acute myelogenous leukemia. Two patents, WO2015180549A1 and CN201410047904.X, covered the development of the I-type crystal, stability experiment, conversion rate research, bioavailability experiment, safety assessment, and solubility study. HAO472 hewed out new avenues to explore the therapeutic properties of oridonin derivatives and develop promising treatment of cancer originated from naturally derived drug candidates. Herein, we sought to overview recent progress of the synthetic, physiological, and pharmacological investigations of oridonin and its derivatives, aiming to disclose the therapeutic potentials and broaden the platform for the discovery of new anticancer drugs.

Activated toll-like receptor 4 is involved in oridonin-induced phagocytosis via promotion of migration and autophagy-lysosome pathway in RAW264.7 macrophages.

In our previous study, we demonstrated that oridonin enhances phagocytosis of apoptotic bodies by macrophage-like cells by inducing autophagy. However, the direct sensor of autophagy and the key event controlling phagocytosis remains unknown. Herein, we showed that Toll-like receptor 4 (TLR4), known to mediate immune responses, was activated by oridonin. Activated TLR4 contributes to phagocytosis of apoptotic cells by RAW264.7 macrophages. Indeed, inhibition or small interfering RNA (siRNA) silencing of TLR4 significantly attenuated oridonin-induced phagocytosis. Inhibition of TLR4 also decreased the level of autophagy and its associated proteins, Beclin-1 and light chain 3 (LC3), suggesting that activated TLR4 is involved in activation of autophagy. LPS-induced activation of TLR4 promoted phagocytosis and autophagy progression. Activation of TLR4 accompany increase in activities of lysosome acid phosphatase and cathepsin B as well as in up-regulation of lysosomal-associated membrane protein (LAMP 1 and 2) levels. Furthermore, TLR4 in association with translocation to cytoplasm leads to macrophage motility or migration through increased plasticity of skeleton and/or membrane structure. These results suggest that oridonin-induced phagocytosis of apoptotic bodies by macrophages is TLR4 signal pathway-mediated, via activation of the autophagy-lysosome pathway as well as increase of cell migration.

Novel enmein-type diterpenoid hybrids coupled with nitrogen mustards: Synthesis of promising candidates for anticancer therapeutics.

Natural derived enmein-type diterpenoids exert cytotoxicity against a wide range of human cancer cells. Yet their medicinal applications are hindered by insufficient potency for chemotherapy. Hence, a series of novel enmein-type diterpenoid hybrids coupled with nitrogen mustards were designed and synthesized to increase antitumor efficacy while reducing systemic toxicity. Most conjugates exhibited stronger antiproliferative activities than parent diterpenoids and nitrogen mustards, especially for multidrug-resistant tumor cell line Bel-7402/5-FU. Among them, compound E2 showed the most potent inhibitory activities in human leukemia HL-60 cells, human prostate cancer PC-3 cells, human liver cancer Bel-7402 cells and drug-resistant human liver cancer Bel-7402/5-FU cells with IC50 values of 7.83 µM, 3.97 µM, 0.77 µM and 2.07 µM, respectively. Additionally, high selectivity with selectivity index over 130 was also observed from cytotoxic evaluation between L-02 human normal liver cells and Bel-7402 malignant liver cells. Further studies on mechanism of action indicated that E2 induced both apoptosis and G1 phase cell cycle arrest in Bel-7402 hepatoma cells. Moreover, the dysfunction in mitochondrial pathway was also involved in E2 initiated apoptotic activation, which entailed the loss of mitochondrial membrane potential followed by upregulating the bax/bcl-2 ratio and increasing the expression of cytochrome c, p53, caspase-3 and -9. Overall, E2 has the potential to emerge as a promising drug candidate for cancer therapy.

Nitric oxide-releasing derivatives of brefeldin A as potent and highly selective anticancer agents.

A series of NO-donating mono- or diester derivatives of brefeldin A were designed, synthesized and biologically evaluated. Some derivatives exhibited potent antiproliferative activity with low IC50 values. The most potent NO-donating hybrid 13b exhibited stronger cytotoxicity against human prostate cancer PC-3 cells, human colon carcinoma HT-29 cells and human liver cancer HepG-2 cells than BFA with IC50 values of 25 nM, 160 nM and 180 nM, respectively. More importantly, compound 13b showed good selectivity between human normal and tumor liver cells with selectivity index of 33. Additionally, 13b released higher levels of NO in HepG-2 cells than L-02 cells. Further mechanism concerning cellular apoptosis showed that 13b induced apoptosis and S phase cell cycle arrest in HepG-2 cells. Incubation with 13b increased the number of HepG-2 cells with collapsed mitochondrial membrane at low concentrations in dose-dependent manner. In addition, by using the Human Apoptosis Protein Array kit, several apoptosis-related proteins, including HO-1, HO-2 and survivin, were found to be markedly downregulated by 13b in HepG-2 cells. Furthermore, in western blot assay, 13b increased the expression of Bax, Cyt c and caspase 3, and reduced the relative levels of Bcl-2, Bcl-xl and pro-caspase 3 in HepG-2 cells.

Nitric oxide induces apoptosis and autophagy; autophagy down-regulates NO synthesis in physalin A-treated A375-S2 human melanoma cells.

Physalin A is an active withanolide isolated from Physalis alkekengi var. franchetii, a traditional Chinese herbal medicine named Jindenglong, which has been used for the treatment of sore throat, hepatitis, eczema and tumors in China. Our previous study demonstrated that physalin A induced apoptosis and cyto-protective autophagy in A375-S2 human melanoma cells. Induction of reactive oxygen species (ROS) with physalin A triggered apoptosis. In this study, NO generated by physalin A induced apoptosis and autophagy in A375-S2 cells, since physalin A induced the expression of inducible nitric oxide synthase (iNOS) in the cells. Generation of NO partially promoted both apoptosis and autophagy in A375-S2 cells. NO suppressed mTOR expression, which led to autophagy induction. An autophagic inhibitor, 3-methyladenine (3MA) promoted NO production, while acceleration of autophagy with an autophagic agonist rapamycin repressed NO production, suggesting that autophagy and NO production form a negative feedback loop that eventually protects the cells from apoptosis. The results together with the previous study indicate apoptosis and autophagy induced by physalin A in A375-S2 cells; the autophagy, repressing production of reactive nitrogen species (RNS) and ROS, protects the cells from apoptosis.

Reactive oxygen species H2O2 and •OH, but not O2•(-) promote oridonin-induced phagocytosis of apoptotic cells by human histocytic lymphoma U937 cells.

We reported previously that phagocytosis of apoptotic cells by U937 cells was enhanced by the treatment with oridonin that showed high activity to induce the generation of reactive oxygen species (ROS) in many cells. ROS, important signaling molecules, are involved in the immune defenses, cell repair and proliferation. In this study, oridonin caused modest amount of ROS generation in U937 cells, with hydrogen peroxide (H2O2) and hydroxyl free radical (OH) as the major types. Meanwhile, H2O2 and OH were positive regulators involved in oridonin-enhanced engulfment of apoptotic cells through down-regulating mitochondrial membrane potential (MMP) and inducing autophagy. The ROS-mediated phagocytosis was independent of cellular adenosine triphosphate (ATP) levels. H2O2 and OH generation also activated phosphatidylinositol 3-kinases-Akt (PI3K-Akt) and phospholipase C γ-protein kinase C(PLC γ)-Ras-Raf-ERK signaling pathways, which were essential for oridonin-induced engulfment of apoptotic cells. Phagocytosis, the loss of MMP, autophagy and the activated signaling pathways were all suppressed by ROS scavenger N-acetyl-l-cysteine (NAC), H2O2 scavenger catalase or OH scavenger glutathione (GSH). However, superoxide anion (O2-) and its scavenger superoxide dismutase (SOD) did not significantly affect these oridonin-induced biological processes.