The effects and side effects of laquinimod for the treatment of multiple sclerosis patients: a systematic review and meta-analysis of clinical trials.

PURPOSE: Although studies have shown the efficacy of laquinimod (LAQ) on disease progression in patients with multiple sclerosis (MS), there is some controversy about whether it improves the types of outcomes and side effects. The main purpose of the present study was to systematically review and meta-analyze the efficacies and side effects of LAQ in patients with relapsing-remitting MS (RRMS). METHODS: PubMed, Scopus, and Web of Science databases were searched with relevant keywords for articles published up to June 2019. Six randomized control trials that examined LAQ vs. placebo in adult patients with MS were included. Information on the effectiveness and side effects of LAQ were extracted. The quality of the included studies was appraised using Jadad scores, and the data were divided into subgroups according to different doses and periods. RESULTS: Efficacy of LAQ: The number of Gadolinium-enhancing (GDE) lesions significantly decreased after treatment with LAQ (SMD = -0.15, 95% CI: -0.23, -0.07), but there was no significant reduction in the number of T2 lesions (SMD = -0.38, 95% CI: -1.04, 0.28). The relapse rate (SMD = -0.13, 95% CI: -0.21, -0.04) and MS Functional Composite (MSFC) score significantly decreased with LAQ treatment (SMD =0.14, 95% CI: 0.05, 0.23). Risk of adverse events: The risk of diarrhea, nausea, abdominal pain, and all adverse events did not significantly increase (p > 0.05) with treatment with LAQ; however, the risk of back pain, headache, and vomiting significantly increased (p < 0.05). The change in mortality rate was not significant (OR = 0.25, 95% CI: 0.04, 1.50). CONCLUSIONS: LAQ can considerably improve clinical and imaging outcomes in RRMS patients. The most effective dose of LAQ with lower side effects may be 0.6 mg/day for at least 2 years, but more evidence is needed to confirm these results.Laquinimod can improve clinical and imaging outcomes in patients with multiple sclerosis.Back pain and headache are probable side effects of laquinimod in patients with multiple sclerosis.The most effective and safe dose of laquinimod for patients with multiple sclerosis may be 0.6 mg/day for 2 years.

Selectivity of major isoquinoline alkaloids from Chelidonium majus towards telomeric G-quadruplex: A study using a transition-FRET (t-FRET) assay.

BACKGROUND: Natural bioproducts are invaluable resources in drug discovery. Isoquinoline alkaloids of Chelidonium majus constitute a structurally diverse family of natural products that are of great interest, one of them being their selectivity for human telomeric G-quadruplex structure and telomerase inhibition. METHODS: The study focuses on the mechanism of telomerase inhibition by stabilization of telomeric G-quadruplex structures by berberine, chelerythrine, chelidonine, sanguinarine and papaverine. Telomerase activity and mRNA levels of hTERT were estimated using quantitative telomere repeat amplification protocol (q-TRAP) and qPCR, in MCF-7 cells treated with different groups of alkaloids. The selectivity of the main isoquinoline alkaloids of Chelidonium majus towards telomeric G-quadruplex forming sequences were explored using a sensitive modified thermal FRET-melting measurement in the presence of the complementary oligonucleotide CT22. We assessed and monitored G-quadruplex topologies using circular dichroism (CD) methods, and compared spectra to previously well-characterized motifs, either alone or in the presence of the alkaloids. Molecular modeling was performed to rationalize ligand binding to the G-quadruplex structure. RESULTS: The results highlight strong inhibitory effects of chelerythrine, sanguinarine and berberine on telomerase activity, most likely through substrate sequestration. These isoquinoline alkaloids interacted strongly with telomeric sequence G-quadruplex. In comparison, chelidonine and papaverine had no significant interaction with the telomeric quadruplex, while they strongly inhibited telomerase at transcription level of hTERT. Altogether, all of the studied alkaloids showed various levels and mechanisms of telomerase inhibition. CONCLUSIONS: We report on a comparative study of anti-telomerase activity of the isoquinoline alkaloids of Chelidonium majus. Chelerythrine was most effective in inhibiting telomerase activity by substrate sequesteration through G-quadruplex stabilization. GENERAL SIGNIFICANCE: Understanding structural and molecular mechanisms of anti-cancer agents can help in developing new and more potent drugs with fewer side effects. Isoquinolines are the most biologically active agents from Chelidonium majus, which have shown to be telomeric G-quadruplex stabilizers and potent telomerase inhibitors.

Dose-dependent cytotoxic effects of boldine in HepG-2 cells-telomerase inhibition and apoptosis induction.

Plant metabolites are valuable sources of novel therapeutic compounds. In an anti-telomerase screening study of plant secondary metabolites, the aporphine alkaloid boldine (1,10-dimethoxy-2,9-dihydroxyaporphine) exhibited a dose and time dependent cytotoxicity against hepatocarcinoma HepG-2 cells. Here we focus on the modes and mechanisms of the growth-limiting effects of this compound. Telomerase activity and expression level of some related genes were estimated by real-time PCR. Modes of cell death also were examined by microscopic inspection, staining methods and by evaluating the expression level of some critically relevant genes. The growth inhibition was correlated with down-regulation of the catalytic subunit of telomerase (hTERT) gene (p < 0.01) and the corresponding reduction of telomerase activity in sub-cytotoxic concentrations of boldine (p < 0.002). However, various modes of cell death were stimulated, depending on the concentration of boldine. Very low concentrations of boldine over a few passages resulted in an accumulation of senescent cells so that HepG-2 cells lost their immortality. Moreover, boldine induced apoptosis concomitantly with increasing the expression of bax/bcl2 (p < 0.02) and p21 (p < 0.01) genes. Boldine might thus be an interesting candidate as a potential natural compound that suppresses telomerase activity in non-toxic concentrations.

Antiproliferative effect of the isoquinoline alkaloid papaverine in hepatocarcinoma HepG-2 cells--inhibition of telomerase and induction of senescence.

Cancer cells are often immortal through up-regulation of the hTERT gene, which encodes the catalytic subunit of a special reverse transcriptase to overcome end-replication problem of chromosomes. This study demonstrates that papaverine, an isoquinoline alkaloid from the Papaveraceae, can overcome telomerase dependent immortality of HepG-2 cells that was used as a model of hepatocarcinoma. Although this alkaloid does not directly interact with telomeric sequences, papaverine inhibits telomerase through down-regulation of hTERT, which was analysed using thermal FRET and qRT-PCR, respectively. The IC50 values for the reduction of both telomerase activity and hTERT expression was 60 µM, while IC50 for cytotoxicity was 120 µM. Repeated treatments of the cells with very low non-toxic concentrations of papaverine resulted in growth arrest and strong reduction of population doublings after 40 days. This treatment induced senescent morphology in HepG-2 cells, which was evaluated by beta-galactosidase staining. Altogether, papaverine can be regarded as a promising model compound for drug design targeting cancer development.

Considering the Effect of Rosa damascena Mill. Essential Oil on Oxidative Stress and COX-2 Gene Expression in the Liver of Septic Rats.

OBJECTIVES: Sepsis is a clinical illness with a high rate of mortality all over the world. Oxidative stress is considered the main phenomenon that occurs in sepsis. Rosa damascena Mill. is an ancient herbal plant with high pharmacological activities. MATERIALS AND METHODS: Cecal ligation and puncture (CLP) as a standard model was used to induce sepsis in rats. Male adult rats were randomly divided into 5 groups. Different doses of R. damascena essential oil (50 and 100 mg/kg.bw) were gavaged orally for 14 days and on day 15 CLP was performed. After 24 h, blood samples and liver tissues were removed in order to measure oxidative stress [myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), glutathione-S-transferase, and ferric reducing ability of plasma (FRAP)] and biochemical parameters [alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), and bilirubin] together with plasma prostaglandin E2 (PGE2) and COX-2 expression. RESULTS: The essential oil was capable of modulating all of the oxidative stress, antioxidant, and anti-inflammatory parameters induced by CLP as characterized by elevations in MPO and MDA levels as well as increases in AST and ALT concentrations concomitant with PGE2 and COX-2 increments. The antioxidant defense system such as GSH and FRAP was also increased in the essential oil treated groups. CONCLUSION: Our results showed that the essential oil has antioxidative and hepatoprotective activities through reducing the oxidative injury in sepsis caused by CLP.

DNA damage and telomere length shortening in the peripheral blood leukocytes of 20 years SM-exposed veterans.

Sulfur mustard (SM) is a vesicant chemical warfare agent, and a very potent alkylating agent. SM exerts its cytotoxicity via direct alkylation of biomacromolecules, and overproduction of reactive oxygen species (ROS). Previous studies have shown that SM-induced oxidative stress has adverse effects on antioxidant defense system, and damages lipids and proteins. The aim of this study was to investigate the effect of SM-induced oxidative stress on DNA damage, and cellular senescence in SM-exposed victims. For this purpose, MDA levels as a measure of oxidative stress in the serum, 8-oxo-dG content of the genomic DNA, and OGG1 expression as two biomarkers of oxidative DNA damage, as well as, telomere length, and p16INK4a expression as two biomarkers of cellular senescence were measured in the peripheral blood leukocytes of 215 males who were exposed to SM 20 to 25 years ago, and 53 unexposed healthy males as the control group. Our results indicated that the levels of 8-oxo-dG, and OGG1 mRNA expression were significantly higher in SM-exposed individuals. Furthermore, a significant increase in the expression of p16INK4a was observed in SM-exposed patients, and leukocyte telomere length (LTL) was also significantly shorter in severe/very severe cases of SM-exposed patients when compared with unexposed controls. In conclusion, our data indicate that oxidative DNA damage is higher in SM-exposed patients, and their immune system has subjected to cellular senescence.

Multiple mechanisms of cell death induced by chelidonine in MCF-7 breast cancer cell line.

In a preliminary study screening anti-proliferative natural alkaloids, a very potent benzophenanthridine, chelidonine showed strong cytotoxicity in cancer cells. While several modes of death have been identified, most of anti-cancer attempts have focused on stimulation of cells to undergo apoptosis. Chelidonine seems to trigger multiple mechanisms in MCF-7 breast cancer cells. It induces both apoptosis and autophagy modes of cell death in a dose dependent manner. Alteration of expression levels of bax/bcl2, and dapk1a by increasing concentration of chelidonine approves switching the death mode from apoptosis induced by very low to autophagy by high concentrations of this compound. On the other hand, submicromolar concentrations of chelidonine strongly suppressed telomerase at both enzyme activity and hTERT transcriptional level. Long exposure of the cells to 50 nanomolar concentration of chelidonine considerably accelerated senescence. Altogether, chelidonine may provide a promising chemistry from nature to treat cancer.

Antiproliferative effects of crocin in HepG2 cells by telomerase inhibition and hTERT down-regulation.

Crocin, the main pigment of Crocus sativus L., has been shown to have antiproliferative effects on cancer cells, but the involved mechanisms are only poor understood. This study focused on probable effect of crocin on the immortality of hepatic cancer cells. Cytotoxicity of crocin (IC50 3 mg/ml) in hepatocarcinoma HepG2 cells was determined after 48 h by neutral red uptake assay and MTT test. Immortality was investigated through quantification of relative telomerase activity with a quantitative real-time PCR-based telomerase repeat amplification protocol (qTRAP). Telomerase activity in 0.5 µg protein extract of HepG2 cells treated with 3 mg/ml crocin was reduced to about 51% as compared to untreated control cells. Two mechanisms of inhibition, i.e. interaction of crocin with telomeric quadruplex sequences and down regulation of hTERT expression, were examined using FRET analysis to measure melting temperature of a synthetic telomeric oligonucleotide in the presence of crocin and quantitative real-time RT-PCR, respectively. No significant changes were observed in the Tm telomeric oligonucleotides, while the relative expression level of the catalytic subunit of telomerase (hTERT) gene showed a 60% decrease as compared to untreated control cells. In conclusion, telomerase activity of HepG2 cells decreases after treatment with crocin, which is probably caused by down-regulation of the expression of the catalytic subunit of the enzyme.

Transcriptional down regulation of hTERT and senescence induction in HepG2 cells by chelidonine.

AIM: To investigate the potential effects of chelidonine, the main alkaloid of Chelidonium majus, on telomerase activity and its regulation in HepG2 cells. METHODS: Cytotoxicity of chelidonine for HepG2 cells was determined by neutral red assay. A modified polymerase chain reaction (PCR)-based telomerase repeat amplification protocol was used to estimate relative telomerase activity in chelidonine-treated cells in comparison with the untreated control cells. Relative expression level of the catalytic subunit of telomerase (hTERT) gene and P-glycoprotein (pgp) were estimated using semi-quantitative real-time reverse transcription-PCR (RT-PCR). Cell senescence in treated cells was demonstrated using a beta-galactosidase test. RESULTS: Cytotoxicity of chelidonine in HepG2 cells was not dose-dependent and tended to reach plateau immediately after the living cells were reduced in number to slightly higher than 50%. However, 12 micromol/L concentration of chelidonine was considered as LD(50), where the maximal attainable effects were realized. Real-time RT-PCR data showed that the expression of pgp increased three-fold in chelidonine treated HepG2 cells in comparison with the untreated controls. Morphologically, treated HepG2 cells showed apoptotic features after 24 h and a small fraction of cells appeared with single blister cell death. The relative expression level of Bcl-2 dropped to less than 50% of control cells at a sub-apoptotic concentration of chelidonine and subsequently increased to higher than 120% at LD(50). Telomerase activity was reduced considerably after administration of very low doses of chelidonine, whereas higher concentrations of chelidonine did not remarkably enhance the effect. Real-time RT-PCR experiments indicated a drastic decrease in expression level of hTERT subunit of telomerase under treatment with chelidonine. Repeated treatment of cells with very low doses of chelidonine caused a decline in growth rate by 4 wk and many of the cells appeared to be aged with large volume and dark staining in the beta-galactosidase assay. CONCLUSION: Chelidonine reduces telomerase activity through down-regulation of hTERT expression. Senescence induction might not be directly caused by reducing telomerase activity as it occurs after a few population doublings.