Atorvastatin enhances apoptotic effects of tamoxifen on melanoma cancer cells.

AIM: Tamoxifen engages mitochondrial estrogen receptor beta as an antagonist, increases mitochondrial cytotoxicity and induces tumor cell death. Tamoxifen also engages plasma membrane estrogen receptor alpha as an agonist, while it is suggested that in some users its activation is put into action by mechanism of resistance to tamoxifen. Apoptotic inducers have been shown to promote tamoxifen-induced cell death, which might be of great importance in overcoming tamoxifen resistance. Considering the pleiotropic effects of statins, in the present study, we investigated the effects of atorvastatin on tamoxifen-induced intrinsic apoptotic pathway activity in melanoma cells. METHODS: Melanoma B16F10 cells were treated for 24 and 48 h with various concentrations of tamoxifen, atorvastatin and combination of tamoxifen + atorvastatin. Cells with no treatment were considered a control group, and the study was then followed by quantitative RT- PCR assay. Bax and cytochrome c gene expressions were calculated by ΔΔct method. RESULTS: Co-treatment of atorvastatin + tamoxifen could strongly enhance the expression of pro/apoptotic factors of Bax and cytochrome c in melanoma cells compared to the tamoxifen and atorvastatin groups. CONCLUSION: In general, we conclude that the atorvastatin-induced increase in Bax and cytochrome c gene expression might be a permissive response to tamoxifen-induced cell death (Fig. 2, Ref. 37).

Influence of morphine on TLR4/ NF-kB signaling pathway of MCF-7 cells.

Morphine affects the risk of metastasis in cancer. The TLR4 gene promotes migration in adenocarcinoma cells. We investigated the effect of morphine on TLR4, MyD88 and NF-κ B-expression and migration. Migration of estrogen receptor-positive MCF7 breast cancer cells was studied after 24 and 48 hours incubation with morphine, with boyden chamber method. Morphine effect on TLR4, MyD88 and NF-κB mRNA expression was determined by quantitative Real-Time polymerase chain reaction. Migration was reduced at the doses of 0.5 and 5 µM (p < 0.05). However, TLR4, MyD88 and NF-κBmRNA expression was decreased at the doses of 0.5, 5 and 500 µM. Morphine at the dose of 50 µM increased the expression of mentioned genes. MCF-7 cell line after 48 hours incubation with the dose of 0.5 µM morphine decreased the migration and at the dose of 0.5 µM down-regulated the mRNA expression of TLR4, MyD88 and NF-κB, however, the higher doses increased the expression of TLR4, MyD88 and NF-κB. Morphine affects TLR4expression in breast cancer cell, which depends on time and concentration (Tab. 1, Fig. 5, Ref. 24).

Effect of lipopolysaccharide on toll-like receptor-4 signals in mouse cancer cells.

BACKGROUND: Recent findings showed that activated TLR signals on cancer cells might promote cancer progression. This study was designed to explore the influence of Toll-like receptor 4 (TLR4) agonist lipopolysaccharides (LPS) on mouse melanoma and breast cancer cell proliferation and their TLR4 signalling. METHODS: Mouse melanoma cell line (B16F10) and breast cancer cell line (4T1) were taken as models. They were treated with LPS (0, 1.25, 2.5, 5, 7.5, 10 µg/ml) for 4, 16, 24, 48 h and MTT assay was done. The expression of TLR4, MyD88, NF-κB mRNA was detected by quantitative real time-polymerase chain reaction method quantitatively. RESULTS: Ultra-pure LPS at 5 µg/ml concentration increased significantly B16F10 cell viability 24 hour after stimulation, but not in 4T1 cell. The mRNA levels of TLR4, MyD88 and NF-κB were significantly up-regulated in both cell lines by stimulating the cells at 5 µg/ml LPS. CONCLUSIONS: Our data demonstrated that B16F10 and 4T1 cells are responsive to LPS, but their responses are time and dose dependent. These results provide new ways to understand the TLR4 signalling in tumour cells (Fig. 2, Ref. 24).

The effect of fenofibrate, a PPARα activator on toll-like receptor-4 signal transduction in melanoma both in vitro and in vivo.

BACKGROUND: The anti-cancer effect of peroxisome proliferator-activated receptor (PPAR) α ligands on growth and metastatic potential of melanoma cells has been shown previously. However, the mechanism underlying these effects remains to be elucidated. Here, we investigated the effects of fenofibrate (PPAR ligand) on Toll-like receptor-4 (TLR-4) signaling in mice melanoma. METHODS: Mice melanoma cells (B16F10) were treated with fenofibrate or LPS or LPS + fenofibrate or pre-treated with CLI-095 (a TLR4 inhibitor), followed by fenofibrate. In in vivo model, C57BL/6 mice were subcutaneously injected with B16F10 cells (with/without LPS pre-treatment), and fenofibrate was administrated after development of palpable tumors. Cell proliferation, the expression level of Tlr4, Myd88, Nf-κb1 genes, TLR-4 protein expression, TNF-α levels, and tumor volume were measured. RESULT: Our results indicated that fenofibrate significantly inhibited the Tlr-4, Myd-88, and Nf-kb1 mRNA expression and TNF-α concentration in B16F10 LPS-stimulated cells. In addition, blocking TLR-4 signaling increased the anti-inflammatory potential of fenofibrate. Also fenofibrate can reduce LPS-induced tumor volume, Tlr-4, Myd-88, Nf-kb1 mRNA, and TLR-4 protein expression in tumor tissue and also TNF-α level in tumor tissue lysate. CONCLUSION: Our data indicate that fenofibrate may exert its anti-melanoma effects via interaction with TLR4-dependent signaling pathway (TLR-4/MyD-88/ NF-kB).

Gender differences in a mouse model of chemotherapy-induced neuropathic pain.

Chemotherapy-induced neuropathic pain is one of the major problems for cancer patients. Although paclitaxel and cisplatin are widely used in women, most laboratory studies of chemotherapy-induced neuropathic pain have been conducted on male animals. The current study examined the gender differences in chemotherapy-induced neuropathic pain in mice. Neuropathic pain was induced by intraperitoneal injection of paclitaxel (2 mg/kg) for five consecutive days and cisplatin (1 mg/kg) for seven consecutive days. Cold allodynia was evaluated by measuring the paw withdrawal frequency and duration of paw licking in mice; however, mechanical allodynia was assessed by von Frey filaments. Neuropathic pain began to manifest after a few days (P < 0.001). Cold allodynia was more robust in female mice (P < 0.001) treated with paclitaxel, while no differences were observed between the two genders in the manifestation of paclitaxel-induced mechanical allodynia. Interestingly, no gender differences were observed in cisplatin-induced cold and mechanical allodynia tests. In conclusion, gender differences play a major role in neuropathic pain induced by paclitaxel. The differences between male and female animals should be considered in future studies and the findings should be generalized to humans with caution.

Anxiolytic effects of Salvia reuterana Boiss. on the elevated plus-maze model of anxiety in mice.

The anxiolytic and sedative effects of hydroalcoholic extract (HE) of Salvia reuterana Boiss. was evaluated in mice. The HE of Salvia reuterana (100 mg/kg), increased the percentage of time-spent and the percentage of arm entries in the open arms of the elevated plus-maze. Spontaneous locomotor activity count measured in 15 min of the test was significantly decreased in animals pretreated with diazepam and 100 mg/kg of Salvia reuterana extract. Results of the present study provide support for the traditional usage of Salvia reuterana as a sedative and anxiolytic medicinal plant.

Anxiolytic effects of Echium amoenum on the elevated plus-maze model of anxiety in mice.

The ethanolic extract of Echium amoenum flowers at the dose of 50 mg/kg increased the percentage of time-spent and the percentage of arm entries in the open arms of the elevated plus-maze (EPM) and decreased the percentage of time-spent in the closed arms of EPM. Moreover, it prolonged the ketamine-induced latency to sleep but had no significant effects on total sleeping time induced by ketamine. Also, the locomotor activity was affected but not to the same extent as observed for diazepam. These results suggested that the extract of E. amoenum seems to possess anxiolytic effect with lower sedative activity than that of diazepam.

The effect of nimodipine on memory loss following naloxone-induced morphine withdrawal in object recognition.

We have previously evaluated the effect of nimodipine, L-type calcium channel blocker, on memory loss during spontaneous morphine withdrawal. In the present study the effect of nimodipine on memory loss in naloxone-induced morphine withdrawal mice was investigated. Mice were made dependent by increasing doses of morphine for three days. Object recognition task that was used for evaluation of memory performance comprised of three sections: 15 min habitation, 12 min first trial and 5 min test trial. Naloxone was injected 3 h after the administration of the last dose of morphine. Recognition index was evaluated 20 min after naloxone injection. Nimodipine was administrated in repeated form (1, 5 and 10 mg/kg) with daily doses of morphine or as a single injection (5 and 10 mg/kg) on the last day. Both acute and repeated treatments with nimodipine prevented the memory impairment in naloxone-induced morphine withdrawal mice (P<0.05 comparison of acute and repeated treatment data with their corresponding control values). Corticosterone concentration was significantly increased in the brain and blood of the mice during withdrawal. Pretreatment with nimodipine, however, decreased the corticosterone concentration in both brain and blood. The present study showed that nimodipine prevents intense memory loss following naloxone-induced morphine withdrawal.

The effect of AM281, a cannabinoid antagonist, on memory performance during spontaneous morphine withdrawal in mice.

Abrupt cessation of morphine leads to withdrawal signs and cognitive deficits. Endocannabinoid system is activated during withdrawal; therefore, the aim of the present study was to assess the effects of AM281, cannabinoid antagonist/inverse agonist, on memory deficit following spontaneous morphine withdrawal. Cognition was evaluated by using the object recognition task. The novel object recognition task was tested in a square wooden open-field box using objects. The test was consisting of three sections: 15 min exploration, first trial for 12 min and second one for 5 min. In the second trial the difference in exploration between a previously seen object and a novel one, was considered as an index of memory performance (recognition index - RI). Male mice were made dependent by increasing doses of morphine (30-90 mg/kg) subcutaneously twice daily for 3 days. AM281 (0.62, 1.25 and 2.5 mg/kg) were used in chronic form concurrent with morphine i.p. or acutely (2.5, 5 and 10 mg/kg) on the last day. RI was evaluated on the third day 4 h after the last dose of morphine. Chronic administration of AM281 at 2.5 mg/kg improved RI to the 22.1 ± 4.8 and single dose of AM281 at 5 mg/kg improved the memory impairment to the 8.5 ± 4, as compared with vehicle-treated which was 4.8 ± 2.5. The results suggested that administration of AM281 at a dose of 2.5 mg/kg in chronic form and 5 mg/kg in acute dose improved memory.

Are antioxidants helpful for disease prevention?

Free radicals are produced continuously in the cells as part of normal cellular function, however excess production might play a role in pathophysiology of many disease conditions, including cancer, Alzheimer's disease, atherosclerosis and some of the drug-induced toxicity. Many basic research studies and observational epidemiologic studies in human suggest that antioxidants can prevent oxidative damage. However, this is still a controversial issue because the results of clinical trials have been inconsistent. This article provides a brief overview of some of the diseases which are associated with free radicals, then discusses the roles of some of dietary antioxidant supplements in disease prevention, with particular reference to the findings of latest clinical trials.