Narirutin downregulates lipoxygenase-5 expression and induces G0/G1 arrest in triple-negative breast carcinoma cells.

BACKGROUND: Triple-negative breast cancer (TNBC) accounts for 20% of breast cancer that does not express HER2, progesterone and estrogen receptors. It is associated with a high mortality rate, morbidity, metastasis, recurrence, poor prognosis and resistance to chemotherapy. Lipoxygenase-5 (LOX-5), cyclooxygenase-2 (COX-2), cathepsin-D (CATD), ornithine decarboxylase (ODC) and dihydrofolate reductase (DHFR) are involved in breast cancer carcinogenesis; hence, there is a pressing need to identify novel chemicals that targets these enzymes. Narirutin, a flavanone glycoside abundantly present in citrus fruits, is reported to have immune-modulatory, anti-allergic and antioxidant potential. Still, the cancer chemopreventive mechanism against TNBC has not been explored. METHODS: In vitro experiments, enzyme activity, expression analysis, molecular docking and MD simulation were carried out. RESULTS: Narirutin suppressed the growth of MDA-MB-231 and MCF-7 in a dose-proportional manner. The pronounced effect with >50% inhibition was observed in SRB and MTT assays for MDAMB-231 cells. Unexpectedly, narirutin suppressed the proliferation of normal cells (24.51%) at 100 µM. Further, narirutin inhibits the activity of LOX-5 in cell-free (18.18 ± 3.93 µM) and cell-based (48.13 ± 7.04 µM) test systems while moderately affecting COX-2, CATD, ODC and DHFR activity. Moreover, narirutin revealed a down-regulation of LOX-5 expression with a fold change of 1.23. Besides, MD simulation experiments confirm that narirutin binding forms a stable complex with LOX-5 and improves the stability and compactness of LOX-5. In addition, the prediction analysis demonstrates that narirutin could not cross the blood-brain barrier and did not act as an inhibitor of different CYPs. CONCLUSIONS AND SIGNIFICANCE: Narirutin could be a potent cancer chemopreventive lead for TNBC, further paving the way for synthesizing novel analogues.

Discovery of benzothiazole-based thiazolidinones as potential anti-inflammatory agents: anti-inflammatory activity, soybean lipoxygenase inhibition effect and molecular docking studies.

Despite the greatest achievement in the development of anti-inflammatory agents in the last two decades, the current clinical drugs suffer from a variety of complications in community settings and hospital. There is still an urgent need to design novel molecules with better safety profile and with different molecular targets from those in current clinical use. The aim of this research was to discover a series of benzothiazole-based thiazolidinones with lipoxygenase (LOX) inhibitory activity as a mechanism of anti-inflammatory action. Carrageenan-induced mouse foot paw oedema assay was carried out to determine the anti-inflammatory activity, while LOX inhibition was examined through the conversion of sodium linoleate to 13-hydroperoxylinoleic acid. Molecular docking studies were performed using AutoDock 4.2 software. The anti-inflammatory activity of the title compounds was determined in a range of 18.4%-69.57%, where compound #3 was found to be the most potent (69.57%) and also to be more active than the reference drug indomethacin (47%). Moreover, compound #3 showed the highest LOX inhibitory activity with IC50 of 13 µM being less potent to that of the reference NDGA (IC50 = 1.3 µM). Compound #3 has been identified as lead compound for further modification in an attempt to improve anti-inflammatory and LOX inhibitory activities.

Tumor-killing nanoreactors fueled by tumor debris can enhance radiofrequency ablation therapy and boost antitumor immune responses.

Radiofrequency ablation (RFA) is clinically adopted to destruct solid tumors, but is often incapable of completely ablating large tumors and those with multiple metastatic sites. Here we develop a CaCO3-assisted double emulsion method to encapsulate lipoxidase and hemin with poly(lactic-co-glycolic acid) (PLGA) to enhance RFA. We show the HLCaP nanoreactors (NRs) with pH-dependent catalytic capacity can continuously produce cytotoxic lipid radicals via the lipid peroxidation chain reaction using cancer cell debris as the fuel. Upon being fixed inside the residual tumors post RFA, HLCaP NRs exhibit a suppression effect on residual tumors in mice and rabbits by triggering ferroptosis. Moreover, treatment with HLCaP NRs post RFA can prime antitumor immunity to effectively suppress the growth of both residual and metastatic tumors, also in combination with immune checkpoint blockade. This work highlights that tumor-debris-fueled nanoreactors can benefit RFA by inhibiting tumor recurrence and preventing tumor metastasis.

Omega-3 polyunsaturated fatty acids protect against inflammation through production of LOX and CYP450 lipid mediators: relevance for major depression and for human hippocampal neurogenesis.

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can exert antidepressant, anti-inflammatory and neuroprotective properties, but the exact molecular mechanism underlying their effects is still not fully understood. We conducted both in vitro and clinical investigations to test which EPA or DHA metabolites are involved in these anti-inflammatory, neuroprotective and antidepressant effects. In vitro, we used the human hippocampal progenitor cell line HPC0A07/03C, and pre-treated cells with either EPA or DHA, followed by interleukin 1beta (IL1ß), IL6 and interferon-alpha (IFN-α). Both EPA and DHA prevented the reduction in neurogenesis and the increase in apoptosis induced by these cytokines; moreover, these effects were mediated by the lipoxygenase (LOX) and cytochrome P450 (CYP450) EPA/DHA metabolites, 5-hydroxyeicosapentaenoic acid (HEPE), 4-hydroxydocosahexaenoic acid (HDHA), 18-HEPE, 20-HDHA, 17(18)-epoxyeicosatetraenoic acid (EpETE) and 19(20)-epoxydocosapentaenoic acid (EpDPA), detected here for the first time in human hippocampal neurones using mass spectrometry lipidomics of the supernatant. In fact, like EPA/DHA, co-treatment with these metabolites prevented cytokines-induced reduction in neurogenesis and apoptosis. Moreover, co-treatment with 17(18)-EpETE and 19(20)-EpDPA and the soluble epoxide hydroxylase (sEH) inhibitor, TPPU (which prevents their conversion into dihydroxyeicosatetraenoic acid (DiHETE)/ dihydroxydocosapentaenoic acid (DiHDPA) metabolites) further enhanced their neurogenic and anti-apoptotic effects. Interestingly, these findings were replicated in a sample of n = 22 patients with a DSM-IV Major Depressive Disorder, randomly assigned to treatment with either EPA (3.0 g/day) or DHA (1.4 g/day) for 12 weeks, with exactly the same LOX and CYP450 lipid metabolites increased in the plasma of these patients following treatment with their precursor, EPA or DHA, and some evidence that higher levels of these metabolites were correlated with less severe depressive symptoms. Overall, our study provides the first evidence for the relevance of LOX- and CYP450-derived EPA/DHA bioactive lipid metabolites as neuroprotective molecular targets for human hippocampal neurogenesis and depression, and highlights the importance of sEH inhibitors as potential therapeutic strategy for patients suffering from depressive symptoms.

Erroneous administration of vinblastine.

This case describes a series of errors which resulted in an avoidable death of the patient. Upon being presented with the 83-year-old patient and her complaints, the physician in charge attempted to prescribe Vasolastine (a complex preparation used, for example, in treatment of angiopathy, which is administered intramuscularly once a day). Unfortunately he misspelled the name of the medicine as Vinplastyna--a non-existent preparation. When the patient's daughter went to collect the prescription from the pharmacist she was dispensed Vinblastin (vinblastine--a cytostatic medicine used, for example, in treating Hodgkin's disease, non-Hodgkin's lymphoma, chronic lymphatic leukemia and testicular cancer). The visiting community nurses administered a dose of this medicine on seven consecutive days. Upon being given the seventh dose, the patient displayed symptoms of myelophthisis, and was admitted to an Intensive Care Ward, where despite the treatment, she died.

Synergistic effect of 15-lipoxygenase 2 and radiation in killing head-and-neck cancer.

We previously demonstrated that 15-LOX-2 is significantly reduced in head and neck carcinoma and restoration of 15-LOX-2 expression results in tumor inhibition in HNC. The aim of this study is to evaluate 15-LOX-2 as a candidate for targeted radiotherapy. Molecular subcloning was performed to create a radiation-inducible 15-LOX-2 expression vector in which the full-length 15-LOX-2 cDNA was inserted downstream the recombinant Egr-1 promoter. The radiation-induced downregulations of 15-LOX-2 protein (twofold up) and its main metabolite 15S-HETE (threefold up) were observed in HNC cells transfected with the 15-LOX-2 expression vector after 4 Gy of radiation. Radiation-induced upregulation of 15-LOX-2 resulted in significant induction of apoptosis in HNC cells. Furthermore, survival colony formation was significantly reduced by 4 Gy in the HNC cells containing the 15-LOX-2 expression vector compared with the controls. Radiation-induced upregulation of 15-LOX-2 results in significant induction of apoptosis and enhances killing effect of radiotherapy in HNC. In addition, exogenous addition of 15S-HETE at high concentrations (>/=10 muM) but not at low concentrations induced upregulation of its endogenous ligand PPARgamma. In conclusion, synergistic effect between radiation and 15-LOX-2 was observed in killing HNC. 15-LOX-2 may be a potential target in radiation-targeted therapy of HNC. The 15-LOX-2 inhibition may not be PPARgamma dependent.

Fatality involving vinblastine overdose as a result of a complex medical error.

The purpose of the study is a presentation of a fatal case involving an 83-year-old woman, who died due to an overdose of vinblastine-a cytostatic agent of a vinca alkaloid employed in cancer chemotherapy. The postmortem investigation included an autopsy and histological examination, as well as a toxicological analysis of post-mortem specimens collected in the course of autopsy. The authors performed a toxicological assessment of vinblastine employing liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC-MS-MS-APCI). The determined vinblastine concentration levels amounting to 29 ng/g in blood and 52.5 ng/g in liver were in a considerable excess of values encountered in patients on chemotherapy using the drug. The fatality was investigated in the context of medical error. In the described case, the erroneous and medically unjustified administration of vinblastine was identified by a series of unfortunate events involving as many as three acting consecutively individuals: a physician, a pharmacist and a nurse. The report may thus document the clinical course of vinblastine poisoning along with postmortem changes resulting from the drug action.

Rheumajecta and vasolastine in the treatment of rheumatoid arthritis--the results of a placebo-controlled, double-blind trial of a complementary treatment.

The so called "enzymatic preparations" Rheumajecta and Vasolastine (R & V) belong to the complementary treatments. The preparations have been used for many years in the treatment of patients with rheumatic conditions such as rheumatoid arthritis (RA) in the Netherlands and other countries of Europe, although a proper study showing efficacy was never performed. Therefore a double-blind, placebo-controlled, modified cross-over trial during two periods of 3 months was performed in 34 patients with RA. They were allocated at random to R & V or to placebo injections, all intramuscular. After 3 months of therapy each patient could opt for cross-over in the event of lack of subjective improvement. Clinical assessments including Ritchie's articular index, grip strength, the DUTCH-AIMS questionnaire, ESR and CRP were performed. R & V did not prove to be more effective than placebo. No serious side-effects were seen.

[Rheumajecta and Vasolastine treatment of primary fibromyalgia; results of a randomized placebo-controlled double-blind study]. / Behandeling met Rheumajecta en Vasolastine van primaire fibromyalgie; resultaten van een gerandomiseerd, placebo-gecontroleerd, dubbelblind onderzoek.

Rheumajecta and Vasolastine (R and V) are preparations belonging to complementary medicine. They are applied in rheumatic conditions such as primary fibromyalgia. In this double-blind, modified cross-over trial, the effect of R and V injections was compared with that of placebo over two periods of three months in 30 patients with primary fibromyalgia. No significant differences in effectiveness between R and V and placebo were seen. There were no serious side-effects. R and V are not indicated for primary fibromyalgia unless no more effect than that of placebo is intended.

Inhibition of lipoxygenase (LOX) or of cyclooxygenase (COX) improves survival of rats in endotoxin shock.

In a well defined endotoxin (ET) shock model we compared the influence of a selective LOX-inhibitor FLM 5011 and the COX-inhibitor Acetylsalicylic acid (ASA) on survival as well as on their effects on TXB2 and 6-oxo-PGF1 and on selected parameters characterizing the shock syndrome. Pretreatment with both substances reduced the lethality rate. Neither TXB2 nor the PGF1 concentration revealed a consistent trend after therapeutic intervention. None of the investigated mediators could be identified as the primary "shock mediator".

Antiinflammatory effect of a lipoxygenase inhibitor (FLM 5011) in severe active myocarditis.

FLM 5011 belongs to a group of chemical compounds with isolated lipoxygenase products in human polymorphonuclear leukocytes and alveolar macrophages. FLM 5011 has been shown to be protective against arachidonic acid-induced bronchoconstriction in vitro and in vivo. No severe side-effects were found in extensive tests on acute and subchronic toxicity in animals. In preliminary investigations on patients with severe active myocarditis impressive clinical and histological improvements after administration of FLM 5011 have been obtained, suggesting an antiinflammatory effect of the substance. A follow-up of more than 13 months compared with conventional immunosuppressive therapy indicates potential therapeutic value of this compound on the inflamed myocardium.

Prostaglandins and the gastrointestinal mucosa: are they important in its function, disease, or treatment?

In 1971 interest in the role of prostaglandins in the gastrointestinal tract was stimulated by the publication of two hypotheses--that aspirin damaged the gastric mucosa by inhibiting prostaglandin synthesis (1) and that cholera toxin caused diarrhea by stimulating it (2). Subsequent research into the gastrointestinal actions of prostaglandins has been considerable and now impinges on clinical practice. This paper reviews the involvement of prostaglandins and related compounds in mucosal protection, in ulcer healing, in diarrhea, and in gastrointestinal inflammation, with particular reference to the growing body of human data.

Inhibitors of lipoxygenase products improve survival in traumatic shock.

We have used three selective inhibitors of arachidonic acid metabolism in order to investigate the role of lipoxygenase metabolites in the pathogenesis of traumatic shock (LD90). The following inhibitors were used: CGS-5391B (2.5 mg/kg), a cyclooxygenase and lipoxygenase inhibitor, CGS-5677 (2.0 mg/kg), a selective lipoxygenase inhibitor, and U-60,257 (0.3 mg/kg), a putative inhibitor of glutathione-s-transferase. These inhibitors did not alter arterial blood pressure or heart rate when given to sham shock rats. The traumatic shock model was characterized by a 4.5-fold increase in plasma cathepsin D activity, a 4-fold increase in plasma myocardial depressant factor (MDF) activity, and a mean survival time of 1.5 +/- 0.2 h. Only the dual inhibitor significantly blunted the accumulation of cathepsin D in the plasma (7.5 +/- 0.8 vs 11.3 +/- 0.8 U/ml, p less than 0.01). However, all three inhibitors significantly suppressed plasma MDF accumulation by 50-60%: CGS-5391B, CGS-5677, and U-60,257 (p less than 0.01). Moreover, these three agents significantly improved survival time in traumatic shock. The increased survival time and reduced MDF activity afforded by these inhibitors suggest a significant role for lipoxygenase metabolites, particularly LTC4 and LTD4, in the pathogenesis of traumatic shock.

Therapeutic reduction of ongoing carrageenin-induced inflammation by lipoxygenase, but not cyclooxygenase inhibitors.

A variety of steroidal and nonsteroidal antiinflammatory agents (NSAs) were compared for their effectiveness against a developing acute inflammatory reaction. Only BW 755C [3-amino-1-(m-trifluoromethyl)-phenyl-2-pyrazole] was immediately effective when administered 2 h after carrageenin, as the 3-h swelling was significantly reduced. Dexamethasone, a steroidal antiinflammatory agent, produced a delayed reduction. When administered at 2 h postcarrageenin, there was no effect at 3 h; but at 6 h, dexamethasone significantly reduced the swelling. In contrast, neither of the classic NSAs, aspirin or indomethacin, were effective when administered after the carrageenin. The results demonstrating a postcarrageenin effectiveness by BW 755C and dexamethasone are discussed as a possible reflection of an action on the lipoxygenase pathways of the arachidonic cascade that is not shared by the classic NSA.

Related age changes in the elastase and lipid contents of normal and hemiplegic subjects of various ages.

Elastase and lipid levels of the plasmas of subjects and of those who have suffered a stroke have been measured, and it has been shown that the normal age related fall in elastase content is mirrored more closely by the fall in high density lipoprotein cholesterol than by changes in total cholesterol. After a stroke a peak level of the elastase concentration is reached later than the peak of the total cholesterol, but before the peak for the HDL-cholesterol is attained. Highest levels of the ratio of these two (a major risk factor in vascular disease) appear to precede both the stroke and the elevation of the elastase level at ages below 76 whereas at higher ages than this the elevation of elastase precedes the lipid changes. It is therefore deduced that the whole question of elastolytic activity in the plasma is intimately bound up with the lipid content of the plasma and with the age of the subject as mirrored in the status of the elastic tissue in the vessel wall.