Anticancer properties of propofol-docosahexaenoate and propofol-eicosapentaenoate on breast cancer cells

Propofol inhibits proliferation and invasion of osteosarcoma cells by regulation of microRNA-143 expression

Propofol is one of the extensively commonly used intravenous anesthetic agents. Previous studies have indicated that propofol has the ability to influence the biological behavior of several human cancer cells. However, the effect of propofol on osteosarcoma and its related molecular mechanisms are still not clear. Here we found that propofol significantly elevated the expression of miR-143, inhibited cell proliferation and invasion, and promoted apoptosis in osteosarcoma cell line MG63. Propofol also efficiently decreased protein expression of matrix metalloproteinase 13 (MMP-13). Moreover, the overexpression of miR-143 decreased MMP-13 protein level. Finally, the neutralization of miR-143 by anti-miR-143 antibody reversed the effect of propofol on cell proliferation, apoptosis, and invasion and upregulated MMP-13 expression in MG63 cells. Taken together, propofol may have antitumor potential in osteosarcoma, which is partly due to the downregulation of MMP-13 expression by miR-143.

Metformin-induced killing of triple-negative breast cancer cells is mediated by reduction in fatty acid synthase via miRNA-193b

The anti-diabetic drug metformin (1,1-dimethylbiguanide hydrochloride) reduces both the incidence and mortality of several types of cancer. Metformin has been shown to selectively kill cancer stem cells, and triple-negative breast cancer (TNBC) cell lines are more sensitive to the effects of metformin as compared to luminal breast cancer. However, the mechanism underlying the enhanced susceptibility of TNBC to metformin has not been elucidated. Expression profiling of metformin-treated TNBC lines revealed fatty acid synthase (FASN) as one of the genes most significantly downregulated following 24 h of treatment, and a decrease in FASN protein was also observed. Since FASN is critical for de novo fatty acid synthesis and is important for the survival of TNBC, we hypothesized that FASN downregulation facilitates metformin-induced apoptosis. Profiling studies also exposed a rapid metformin-induced increase in miR-193 family members, and miR-193b directly targets the FASN 3'UTR. Addition of exogenous miR-193b mimic to untreated TNBC cells decreased FASN protein expression and increased apoptosis of TNBC cells, while spontaneously immortalized, non-transformed breast epithelial cells remained unaffected. Conversely, antagonizing miR-193 activity impaired the ability of metformin to decrease FASN and cause cell death. Further, the metformin-stimulated increase in miR-193 resulted in reduced mammosphere formation by TNBC lines. These studies provide mechanistic insight into metformin-induced killing of TNBC.

Regulation of the cancer cell membrane lipid composition by NaCHOleate: effects on cell signaling and therapeutical relevance in glioma

This review summarizes the cellular bases of the effects of NaCHOleate (2-hydroxyoleic acid; 2OHOA; Minerval) against glioma and other types of tumors. NaCHOleate, activates sphingomyelin synthase (SGMS) increasing the levels of cell membrane sphingomyelin (SM) and diacylglycerol (DAG) together with reductions of phosphatidylethanolamine (PE) and phosphatidylcholine (PC). The increases in the membrane levels of NaCHOleate itself and of DAG induce a translocation and overexpression of protein kinase C (PKC) and subsequent reductions of Cyclin D, cyclin-dependent kinases 4 and 6 (CDKs 4 and 6), hypophosphorylation of the retinoblastoma protein, inhibition of E2F1 and knockdown of dihydrofolate reductase (DHFR) impairing DNA synthesis. In addition in some cancer cells, the increases in SM are associated with Fas receptor (FasR) capping and ligand-free induction of apoptosis. In glioma cell lines, the increases in SM are associated with the inhibition of the Ras/MAPK and PI3K/Akt pathways, in association with p27Kip1 overexpression. Finally, an analysis of the Repository of Molecular Brain Neoplasia Data (REMBRANDT) database for glioma patient survival shows that the weight of SM-related metabolism gene expression in glioma patients' survival is similar to glioma-related genes. Due to its low toxicity and anti-tumoral effect in cell and animal models its status as an orphan drug for glioma treatment by the European Medicines Agency (EMA) was recently acknowledged and a phase 1/2A open label, non-randomized study was started in patients with advanced solid tumors including malignant glioma. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.

Effect of opiates, anesthetic techniques, and other perioperative factors on surgical cancer patients

BACKGROUND

Opioid pharmacotherapy is often used to treat cancer pain. However, morphine and other opioid-like substance use in patients with cancer may have significant adverse consequences, including the suppression of both innate and acquired immune responses. Although studies have examined the possibility that regional anesthesia attenuates the immunosuppressive response of surgery, the effects of morphine and other opioid-related substances on tumor progression remain unknown.

METHODS

This article presents an evidence-based review of the influence of opioids and anesthetic technique on the immune system in the context of cancer recurrence. The review focuses on the field of regional anesthesia and the setting of surgical oncologic procedures. The method for perioperative pain management and the technique of anesthesia chosen for patients in cancer surgery were explored.

RESULTS

General anesthetics have been indicated to suppress both cell-mediated immunity and humoral immunity. Evidence suggests that intravenous opioids suppress the immune system. However, the mechanisms by which anesthetics and analgesics inhibit the immune system are not understood. Compared with the alternatives, regional analgesia offers reduced blood loss and superior postoperative analgesia. Because of these advantages, the use of regional analgesia has increased in oncologic surgeries.

CONCLUSION

Immune responses from all components of the immune system, including both the humoral and cell-mediated components, appear to be suppressed by anesthetics and analgesics. The clinical anesthesiologist should consider these factors in the application of technique, especially in cancer surgery.

Propofol induces apoptosis and increases gemcitabine sensitivity in pancreatic cancer cells in vitro by inhibition of nuclear factor-κB activity

AIM: To investigate the effect of propofol on human pancreatic cells and the molecular mechanism of propofol action.

METHODS: We used the human pancreatic cancer cell line MIAPaCa-2 for in vitro studies measuring growth inhibition and degree of apoptotic cell death induced by propofol alone, gemcitabine alone, or propofol followed by gemcitabine. All experiments were conducted in triplicate and carried out on three or more separate occasions. Data were means of the three or more independent experiments ± SE. Statistically significant differences were determined by two-tailed unpaired Student’s t test and defined as P < 0.05.

RESULTS: Pretreatment of cells with propofol for 24 h followed by gemcitabine resulted in 24%-75% growth inhibition compared with 6%-18% when gemcitabine was used alone. Overall growth inhibition was directly correlated with apoptotic cell death. We also showed that propofol potentiated gemcitabine-induced killing by downregulation of nuclear factor-κB (NF-κB). In contrast, NF-κB was upregulated when pancreatic cancer cells were exposed to gemcitabine alone, suggesting a potential mechanism of acquired chemoresistance.

CONCLUSION: Inactivation of the NF-κB signaling pathway by propofol might abrogate gemcitabine-induced activation of NF-κB, resulting in chemosensitization of pancreatic tumors to gemcitabine.

Propofol inhibits the adhesion of hepatocellular carcinoma cells by upregulating microRNA-199a and downregulating MMP-9 expression

BACKGROUND

Propofol is one of the extensively and commonly used intravenous anesthetics and has the ability to influence the proliferation, motility, and invasiveness of many cancer cells. In this study, the effects of propofol on hepatocellular carcinoma cells invasion ability were examined.

METHODS

We assessed the invasion ability of HepG2 cells in vitro by determining enzyme activity and protein expression of MMP-9 using gelatin zymography assay and Western blot. The real-time PCR was used to evaluate the effect of propofol on microRNA-199a (miR-199a) expression, and miR-199a-2 precursor to evaluate whether over-expression of miR-199a can affect MMP-9 expression. Finally, the effect of miR-199a on propofol-induced anti-tumor activity using anti-miR-199a was assessed.

RESULTS

Propofol significantly elevated the expression of miR-199a and inhibited the invasiveness of HepG2 cells. Propofol also efficiently decreased enzyme activity and protein expression of MMP-9. Moreover, the over-expression of miR-199a decreased MMP-9 protein level. Interestingly, the neutralization of miR-199a by anti-miR-199a antibody reversed the effect of propofol on alleviation of tumor invasiveness and inhibition of MMP-9 activity in HepG2 cells.

CONCLUSION

Propofol decreases hepatocellular carcinoma cell invasiveness, which is partly due to the down-regulation of MMP-9 expression by miR-199a.

Choice of anesthetic technique on plasma concentrations of interleukins and cell adhesion molecules

BACKGROUND

Whether inflammatory responses to surgery are comparably activated during total intravenous anesthesia (TIVA) and during volatile anesthesia remains unclear. We thus compared the perioperative effects of TIVA and isoflurane anesthesia on plasma concentrations of proinflammatory and anti-inflammatory interleukins and cell adhesion molecules.

METHODS

Patients having laparoscopic cholecystectomies were randomly allocated to two groups: 44 were assigned to TIVA and 44 to isoflurane anesthesia. IL-1β, IL-6, IL-8, IL-10, IL-13, and the cellular adhesion molecules intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were determined preoperatively, before incision, and at 2 and 24 hours postoperatively. Our primary outcomes were area-under-the-curve cytokine and adhesion molecule concentrations over 24 postoperative hours.

RESULTS

The only statistically significant difference in area-under-the-curve concentrations was for IL-6, which was greater in patients given isoflurane:78 (95% confidence interval (CI): 52 to 109) pg/ml versus 33 (22 to 50) pg/ml, P= 0.006. Two hours after surgery, IL-6 was significantly greater than baseline in patients assigned to isoflurane: 47 (95% CI: 4 to 216, P<0.001) pg/ml versus 18 (95%CI: 4 to 374, P<0.001) pg/ml in the TIVA group. In contrast, IL-10 was significantly greater in patients assigned to TIVA: 20 (95% CI: 2 to 140, P<0.001) pg/ml versus 12 (95% CI: 3 to 126, P<0.001) pg/ml. By 24 hours after surgery, concentrations were generally similar between study groups and similar to baseline values.

CONCLUSION

The only biomarker whose postoperative area-under-the-curve concentrations differed significantly as a function of anesthetic management was IL-6. Two hours after surgery, IL-6 concentrations were significantly greater in patients given isoflurane than TIVA. However, the differences were modest and seem unlikely to prove clinically important. Further studies are needed.

Anticancer efficacy of a novel propofol-linoleic acid-loaded escheriosomal formulation against murine hepatocellular carcinoma

AIM

The preparation and characterization of a novel escheriosomal nanoparticle formulation of a potent anticancer conjugate, 2,6-diisopropylphenol-linoleic acid (2,6P-LA), and evaluation of its anticancer efficacy against diethyl nitrosamine-induced hepatocellular carcinoma (HCC) in BALB/c mice.

MATERIALS & METHODS

Escheriosomized 2,6P-LA nanoparticles were characterized for size, zeta-potential, entrapment efficiency, release kinetics and in vivo toxicity. Their anticancer potential was evaluated on the basis of survival, DNA fragmentation, caspase-3 activation, western blot analysis of apoptotic factors and histopathological changes in hepatocytes of treated animals.

RESULTS

The escheriosomized 2,6P-LA nanoparticles exhibited low toxicity, biocompatibility and bioavailability. As revealed by apoptosis induction, survival rate, expression profiles of Bax, Bcl-2 and caspase-9, escheriosomized 2,6P-LA nanoparticles were more effective in the treatment of HCC than the free form of 2,6P-LA in experimental animals.

CONCLUSION

2,6P-LA-bearing escheriosome nanoparticles are effective in suppressing HCC in mice. Original submitted 17 January 2012; Revised submitted 27 August 2012; Published online 14 January 2013.

Inhibition of matrix metalloproteinase-9 expression by docosahexaenoic acid mediated by heme oxygenase 1 in 12-O-tetradecanoylphorbol-13-acetate-induced MCF-7 human breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays a crucial role in tumor metastasis. Previous studies showed that polyunsaturated fatty acids exhibit an anti-cancer effect in various human carcinoma cells, but the effect of docosahexaenoic acid (DHA) and linoleic acid (LA) on metastasis of breast cancer cells is not fully clarified. We studied the anti-metastasis potential of DHA and LA in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MCF-7 cells. We found that TPA (100 ng/ml) induced MMP-9 enzyme activity both dose- and time-dependently, and 200 μM DHA and LA significantly inhibited MMP-9 mRNA and protein expression, enzyme activity, cell migration, and invasion. Treatment with PD98059 (10 μM), wortmannin (10 μM), and GF109203X (0.5 μM) decreased TPA-induced MMP-9 protein expression and enzyme activity. TPA-induced activation of ERK1, Akt, and PKCδ was attenuated by DHA, whereas LA attenuated only ERK1 activation. GF109203X also suppressed ERK1 activation. EMSA showed that DHA, LA, PD98059, and wortmannin decreased TPA-induced NF-κB and AP-1 DNA-binding activity. Furthermore, DHA rather than LA dose-dependently increased HO-1 expression. HO-1 siRNA alleviated the inhibition by DHA of TPA-induced MMP-9 protein expression and enzyme activity in MCF-7 cells, and HO-1 knockdown reversed the DHA inhibition of cell migration. These results suggest that DHA and LA have both similar and divergent signaling pathways in the suppression of TPA-induced MCF-7 metastasis.

Synthesis and characterization of novel n-9 fatty acid conjugates possessing antineoplastic properties

The present study enumerates the synthesis, spectroscopic characterization, and evaluation of anticancer potential of esters of two n-9 fatty acids viz., oleic acid (OLA) and ricinoleic acid (RCA) with 2,4- or 2,6-diisopropylphenol. The synthesis strategy involved esterification of the hydroxyl group of diisopropylphenol (propofol) to the terminal carboxyl group of n-9 fatty acid. The synthesized propofol-n-9 conjugates having greater lipophilic character were tested initially for cytotoxicity in-vitro. The conjugates showed specific growth inhibition of cancer cell lines whereas no effect was observed in normal cells. In general, pronounced growth inhibition was found against the human skin malignant melanoma cell line (SK-MEL-1). The anticancer potential was also determined by testing the effect of these conjugates on cell migration, cell adhesion and induction of apoptosis in SK-MEL-1 cancer cells. Propofol-OLA conjugates significantly induced apoptosis in contrast to propofol-RCA conjugates which showed only weak signals for cytochrome c. Conclusively, the synthesized novel ester conjugates showed considerable moderation of anti-tumor activity. This preliminary study places in-house synthesized conjugates into the new class of anticancer agents that possess selectivity toward cancer cells over normal cells.

Omega-3 but not omega-6 unsaturated fatty acids inhibit the cancer-specific ENOX2 of the HeLa cell surface with no effect on the constitutive ENOX1

Epidemiological and laboratory studies suggest that dietary fatty acids (oleic acid (in olive oil), eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) (in fish oil)) play important roles in carcinogenesis. The most potent antitumor effects of all fatty acids are given by fatty acid conjugated linoleic acid (CLA). The antitumor effects of CLA may be mediated through enhanced apoptosis. While CLA, EPA, and DHA (omega-3 polyunsaturated fatty acids) have inhibitory effects on cancer cells, omega-6 fatty acids have often shown negative or potentiating effects on cancer cells. Linoleic acid (an omega-6) is desaturated in the cell by delta 6 and 5 destaturases to form arachidonic acid. COX 1 and 2 isoforms then act on arachidonic acid to form prostaglandins and other related regulatory molecules. It is normally thought that what is important to the development of the cancerous phenotype is some balance of these various metabolites. In experiments with surface NOX proteins released from HeLa cells, spectrophotometric measurements of the oxidation of NADH revealed inhibition of the cancer-specific ENOX2 activity by CLA and the omega-3 fatty acids, eicosapentaenoic, docosahexaenoic, and α-linolenic acids. The constitutive ENOX1 activity was not inhibited. In contrast, the omega-6 fatty acids, linoleic acid, and arachidonic acid inhibited neither ENOX1 nor ENOX2. The findings indicate the possibility that a direct effect of CLA and omega-3 fatty acids on ENOX2 may be responsible for the potent activity of CLA and omega-3 fatty acids in cancer prevention and therapy.

In vivo effects of different anesthetic agents on apoptosis

Background

This study was designed to measure in vivo effects of propofol, isoflurane and sevoflurane on apoptosis by measuring caspase-3 and tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) blood level as apoptotic markers.

Methods

After obtaining ethical committee approval and informed written consents, sixty adult patients ASA I scheduled for open cholecystectomy participated in this study. They were randomally allocated into one of three equal groups to receive propofol infusion, low-flow isoflurane or sevoflurane for maintenance of anesthesia. Venous blood samples were collected preoperatively, immediately postoperative and after 24 hours to measure hemoglobin, hematocrit, creatinine, liver enzymes, serum TRAIL and caspase-3 levels.

Results

There was no significant difference in hematological markers and serum creatinine. Liver enzymes showed significant postoperative rise (P < 0.05). In Propofol group, TRAIL and caspase-3 levels were significantly elevated immediately postoperative then decreased significantly after 24-hours (P < 0.05). In Isoflurane group, immediate postoperative level of TRAIL was significantly higher than 24 hours reading and significantly lower than its level in Propofol group at the same timing meanwhile caspase-3 levels were comparable at different timings. In Sevoflurane group, TRAIL and caspase-3 levels increased significantly in both postoperative samples than preoperative level and than those of Isoflurane and Propofol groups after 24 hours concerning TRAIL (P & 0.05).

Conclusions

This study concluded that isoflurane is superior and sevoflurane is the least effective among the three anesthetics in protection against apoptosis. This study neither proved nor excluded propofol-induced apoptosis. Further studies are required during lengthy procedure and in compromised patients.

[Perioperative tumour dissemination. 2. Effects of anaesthesia and analgesia]

There has been growing concern over the last few years on the effect that the anaesthetic drugs used during oncological surgery could have on long-term tumour progression. In laboratory studies, it has been observed how some substances used during the anaesthetic procedure influence tumour immunosurveillance, cell proliferation or tumour angiogenesis processes. The possible clinical relevance of the anaesthetic technique used as regards long-term tumour progression and survival is still to be determined. However, based on retrospective studies, it appears that those anaesthetic techniques combined with the use of regional anaesthesia and analgesia may be beneficial compared to those that are maintained on the use of opioids. Further research should help to clarify the long-term clinical relevance of the anaesthetic process during oncological surgery.

The effects of anesthetic technique on cancer recurrence in percutaneous radiofrequency ablation of small hepatocellular carcinoma

BACKGROUND

Retrospective studies report that the benefit of regional anesthesia on cancer recurrence may depend on the specific tumor type. We compared the association between anesthetic technique and cancer recurrence in patients undergoing percutaneous radiofrequency ablation (RFA) of small hepatocellular carcinoma (HCC).

METHODS

We retrospectively reviewed medical records of patients with small HCC treated with RFA between August 1999 and December 2008. Patients receiving epidural anesthesia were compared with a group given general anesthesia. The end points were recurrence-free survival and overall survival, which were assessed using the Kaplan-Meier technique and compared using a multivariate Cox proportional hazards regression model and an alternative model with inverse probability weights to adjust for propensity score.

RESULTS

The hazard ratio for recurrence-free survival in the epidural anesthesia group compared with the general anesthesia group was 3.66 (95% confidence interval [CI], 2.59-5.15; P < 0.001) in the Cox regression model and 4.31 (95% CI, 2.24-8.29; P < 0.001) in the analysis adjusted for propensity score with inverse probability weights. The hazard ratio for overall survival in the epidural anesthesia group compared with the general anesthesia group was 0.77 (95% CI, 0.50-1.18; P = 0.232) in the Cox regression model and 1.26 (95% CI, 0.81-1.97; P = 0.312) in the analysis adjusted for propensity score with inverse probability weights.

CONCLUSIONS

This retrospective analysis suggests that treatment of small HCC by RFA under general anesthesia is associated with reduced risk of cancer recurrence. No effect of anesthetic technique on overall survival is detected. Prospective, randomized trials to evaluate this association are warranted.

Monoacylglycerol lipase exerts dual control over endocannabinoid and fatty acid pathways to support prostate cancer

Cancer cells couple heightened lipogenesis with lipolysis to produce fatty acid networks that support malignancy. Monoacylglycerol lipase (MAGL) plays a principal role in this process by converting monoglycerides, including the endocannabinoid 2-arachidonoylglycerol (2-AG), to free fatty acids. Here, we show that MAGL is elevated in androgen-independent versus androgen-dependent human prostate cancer cell lines, and that pharmacological or RNA-interference disruption of this enzyme impairs prostate cancer aggressiveness. These effects were partially reversed by treatment with fatty acids or a cannabinoid receptor-1 (CB1) antagonist, and fully reversed by cotreatment with both agents. We further show that MAGL is part of a gene signature correlated with epithelial-to-mesenchymal transition and the stem-like properties of cancer cells, supporting a role for this enzyme in protumorigenic metabolism that, for prostate cancer, involves the dual control of endocannabinoid and fatty acid pathways.

Synthesis and characterization of novel PUFA esters exhibiting potential anticancer activities: an in vitro study

Polyunsaturated fatty acids (PUFAs) have been reported to play a regulatory role in tumour growth progression. In the present study, we have synthesized ester derivatives of two important PUFA viz., linoleic acid (LA) and arachidonic acid (AA) with propofol, a widely used general anaesthetic-sedative agent. The novel propofol ester analogues have been found to inhibit various cancer cell lines in a dose-dependent manner. Moreover, the compounds have been found to induce apoptotic cell death by enhancing the release of cytochrome c and expression of caspase-3. The data of the present study suggest that novel propofol-PUFA esters have strong potential to emerge as effective anticancer agents.

Effect of anaesthetic technique and other perioperative factors on cancer recurrence

Surgical excision is the mainstay of treatment for potentially curable solid tumours. Metastatic disease is the most important cause of cancer-related death in these patients. The likelihood of tumour metastases depends on the balance between the metastatic potential of the tumour and the anti-metastatic host defences, of which cell-mediated immunity, and natural killer cell function in particular, is a critical component. It is increasingly recognized that anaesthetic technique and other perioperative factors have the potential to effect long-term outcome after cancer surgery. Surgery can inhibit important host defences and promote the development of metastases. Anaesthetic technique and drug choice can interact with the cellular immune system and effect long-term outcome. The potential effect of i.v. anaesthetics, volatile agents, local anaesthetic drugs, opiates, and non-steroidal anti-inflammatory drugs are reviewed here. There is particular interest at present in the effect of regional anaesthesia, which appears to be beneficial. Retrospective analyses have shown an outcome benefit for paravertebral analgesia for breast cancer surgery and epidural analgesia for prostatectomy. Blood transfusion, pain, stress, and hypothermia are other potentially important perioperative factors to consider.

Combinatorial effect of fish oil (Maxepa) and 1alpha,25-dihydroxyvitamin D(3) in the chemoprevention of DMBA-induced mammary carcinogenesis in rats

The present study demonstrates the anti-tumor effects of combined supplementations of dietary fish oil (Maxepa) and 1alpha,25-dihydroxyvitamin D(3) (vitamin D(3)) on 7,12-dimethylbenz(alpha)anthracene (DMBA)-induced rat mammary carcinogenesis. Female Sprague-Dawley rats at 50 days of age were treated with 7,12-dimethylbenz(alpha)anthracene (DMBA; 0.5mg/100g body weight) by a single tail vein injection in an oil emulsion. Both fish oil (rich in EPA and DHA) and vitamin D(3) were administered orally at a dose of 0.5 ml/day/rat and 0.3 microg/100 microL propylene glycol twice a week respectively and continued to 35 weeks after DMBA administration. Fish oil in combination with vitamin D(3) resulted in a significant reduction in incidence, multiplicity and volume of mammary tumors. These supplementation also inhibited DMBA-induced mammary 7-methylguanine DNA adducts formation, which was measured by HPLC-fluorescence assay (at four sequential time points; ANOVA, F=42.56, P<0.0001). Immunohistochemical analysis revealed that the effect of fish oil and vitamin D(3) occurred through suppression of cell proliferation (BrdU-LI: P<0.0001). Fish oil and vitamin D(3) together also reduced the mRNA expression of iNOS (84%, P<0.05). In view of their natural availability, non-toxicity and acceptability; combined supplementation of fish oil and vitamin D(3) might be effective for chemoprevention of mammary carcinogenesis.

Beneficial effects of omega-3 long-chain fatty acids in breast cancer and cardiovascular diseases: voltage-gated sodium channels as a common feature?

Cancers are among the leading causes of death worldwide. Voltage-gated sodium channels, among other ion channels, appear as new molecular players in epithelial cancers. Highly metastatic breast cancer cells express Na(V)1.5, the main isoform expressed in cardiac cells, where the current generated by the flux of sodium ions is responsible for the excitability. Breast cancer cells are not excitable and the protein activity regulates cell invasiveness, through the modulation of activity of acidic cathepsins, a characteristic involved in the metastatic phenotype. Interestingly, it is known that ω-3 LC-PUFA can exert beneficial effects by preventing post-myocardial infarction arrhythmias and by reducing the incidence of metastatic breast cancer. In this review, we compare the effects of some ω-3 LC-PUFA on Na(V)1.5 expressed in both cardiac and MDA-MB-231 breast cancer cells. We propose that some of the effects of ω-3 LC-PUFA act through common mechanisms involved in both diseases.

Monoacylglycerol lipase regulates a fatty acid network that promotes cancer pathogenesis

Tumor cells display progressive changes in metabolism that correlate with malignancy, including development of a lipogenic phenotype. How stored fats are liberated and remodeled to support cancer pathogenesis, however, remains unknown. Here, we show that the enzyme monoacylglycerol lipase (MAGL) is highly expressed in aggressive human cancer cells and primary tumors, where it regulates a fatty acid network enriched in oncogenic signaling lipids that promotes migration, invasion, survival, and in vivo tumor growth. Overexpression of MAGL in nonaggressive cancer cells recapitulates this fatty acid network and increases their pathogenicity-phenotypes that are reversed by an MAGL inhibitor. Impairments in MAGL-dependent tumor growth are rescued by a high-fat diet, indicating that exogenous sources of fatty acids can contribute to malignancy in cancers lacking MAGL activity. Together, these findings reveal how cancer cells can co-opt a lipolytic enzyme to translate their lipogenic state into an array of protumorigenic signals. PAPERFLICK:

Characterization of anticancer properties of 2,6-diisopropylphenol-docosahexaenoate and analogues in breast cancer cells

The present study describes the characterization and evaluation of novel anticancer conjugates, 2,6-diisopropylphenol-docosahexaenoate (PP-DHA), and its analogues including 2,4-diisopropylphenol-docosahexaenoate (DIPP-DHA), 2-isopropylphenol-docosahexaenoate (IPP-DHA), 2-cyclohexanephenol-docosahexaenoate (CHP-DHA) and phenol-docosahexaenoate (P-DHA) on breast cancer cell lines. Representative breast cancer cell lines, based on estrogen alpha receptor (ER) and oncogene Her-2 expression, were used and include MDA-MB-231 (ER-negative, Her-2-negative), MCF-7 (ER-positive, Her-2-negative) AU565 (ER-negative, Her-2-positive) and MDA-MB-361 (ER-positive, Her-2-positive). The PP-DHA conjugate significantly inhibited cell growth and induced cell loss in the breast cancer cell lines similarly; however, this conjugate was not effective against normal mammary epithelial cells. The effect of various conjugates were in PP-DHA>IPP-DHA>DIPP-DHA>CHP-DHA>>P-DHA order. PP-DHA and IPP-DHA conjugates were stable in human and mouse serum. Furthermore, the non-hydrolyzable amide-linked conjugate analogues affected breast cancer cells in a manner similar to that of the ester-linked conjugates. This suggests that ester-linked PP-DHA and IPP-DHA conjugates were stable during treatment to breast cancer cells due to structural hindrance. PP-DHA did not affect PPARalpha or PPARgamma activities but its anticancer effects appear to be mediated in part though the inhibition of histone deacetylase (HDAC) activity. Further experiments are needed to confirm their molecular target and to test the effectiveness of these compounds in an in vivo model for their anticancer properties. In conclusion, these results suggest that the novel PP-DHA and IPP-DHA conjugates and their amide derivatives may be useful for the treatment of breast cancer.

Antineoplastic effects of n-3 polyunsaturated fatty acids in combination with drugs and radiotherapy: preventive and therapeutic strategies

Many data support the beneficial effect of n-3 polyunsaturated fatty acids (PUFAs) as chemopreventive and chemotherapeutic agents in the treatment of several chronic pathologies including cancer. Different molecular mechanisms have been proposed to explain their effects, including alterations in arachidonic acid oxidative metabolism and metabolic conversion of n-3 PUFAs to novel discovered bioactive derivatives; modification of oxidative stress; changes in cell membrane fluidity and structure and altered metabolism and function of membrane proteins. Considerable knowledge has been recently gathered on the possible beneficial effects of n-3 PUFAs administered in combination with different antineoplastic drugs and radiotherapy against melanoma, leukemia, neuroblastoma, and colon, breast, prostate, and lung cancer. The efficacy of these combinations has been demonstrated both in vivo and in vitro, and clinical trials have also been conducted. The aim of this review is to analyze all the n-3 PUFA combinations investigated so far, their efficacy, and the possible molecular mechanisms involved. It would be highly auspicable that the detailed analysis of the literature in this field could further support the common use of n-3 PUFAs in combination with other chemopreventive agents and warrant more clinical investigations designed to test the effectiveness of n-3 PUFA treatments coupled with conventional antineoplastic therapies.

Drugs of anaesthesia and cancer

Anaesthesia represents one of the most important medical advances in history, and, nowadays, can widely be considered safe, thanks to the discovery of new drugs and the adoption of modern technologies. Nevertheless, anaesthetic practices still represent cause for concern regarding the consequences they produce. Various anaesthetics are frequently used without knowing their effects on specific diseases: despite having been reported that invasion or metastasis of cancer cells easily occurs during surgical procedures, numerous anaesthetics are used for cancer resection even if their effect on the behaviour of cancer cells is unclear. Guidelines for a proper use of anaesthetics in cancer surgery are not available, therefore, the aim of the present review is to survey available up-to-date information on the effects of the most used drugs in anaesthesia (volatile and intravenous anaesthetics, nitrous oxide, opioids, local anaesthetics and neuromuscular blocking drugs) in correlation to cancer. This kind of knowledge could be a basic valuable support to improve anaesthesia performance and patient safety.

Minerval induces apoptosis in Jurkat and other cancer cells

Minerval is an oleic acid synthetic analogue that impairs lung cancer (A549) cell proliferation upon modulation of the plasma membrane lipid structure and subsequent regulation of protein kinase C localization and activity. However, this mechanism does not fully explain the regression of tumours induced by this drug in animal models of cancer. Here we show that Minerval also induced apoptosis in Jurkat T-lymphoblastic leukaemia and other cancer cells. Minerval inhibited proliferation of Jurkat cells, concomitant with a decrease of cyclin D3 and cdk2 (cyclin-dependent kinase2). In addition, the changes that induced on Jurkat cell membrane organization caused clustering (capping) of the death receptor Fas (CD95), caspase-8 activation and initiation of the extrinsic apoptosis pathway, which finally resulted in programmed cell death. The present results suggest that the intrinsic pathway (associated with caspase-9 function) was activated downstream by caspase-8. In a xenograft model of human leukaemia, Minerval also inhibited tumour progression and induced tumour cell death. Studies carried out in a wide variety of cancer cell types demonstrated that apoptosis was the main molecular mechanism triggered by Minerval. This is the first report on the pro-apoptotic activity of Minerval, and in part explains the effectiveness of this non-toxic anticancer drug and its wide spectrum against different types of cancer.

Fish oil infusion reverses 5-fluorouracil-induced impairments in mucosal immunity in mice

BACKGROUND & AIMS

Anticancer drugs frequently have deleterious effects on host defense against infection, limiting their clinical application. We previously demonstrated continuous infusion of 5-fluorouracil (5FU) to reduce gut associated lymphoid tissue (GALT) mass and secretory IgA levels. This study was designed to examine the effects of concomitant infusion of fish oil on gut mucosal immunity in mice receiving 5FU.

METHODS

Male ICR mice were randomized to the control (n=12), 5FU (n=12), or 5FU+FO (n=10) group. The 5FU and 5FU+FO groups received continuous IV infusion of 5FU at 10 mg/kg for 5 days. The 5FU+FO group was given a simultaneous infusion of 10 ml/kg of a 10% fish oil emulsion. The controls received normal saline at 0.3 ml/h. During these treatments, all mice were allowed free access to chow and water ad libitum. Then, the mice were sacrificed and GALT lymphocytes were isolated from Peyer's patches (PPs), the intraepithelial space (IE), and the lamina propria (LP). Small intestinal, nasal and broncho-alveolar (BALF) washings were also obtained. Lymphocyte yields from each site and phenotypes (CD4, CD8, alphabetaTCR, gammadeltaTCR, B220) were determined. IgA levels in the washings were measured with ELISA.

RESULTS

The 5FU group had significantly lower IE and LP lymphocyte numbers and small intestinal and BALF IgA levels than the control group, with no differences in the percentages of any phenotypes. However, fish oil infusion restored IE and LP lymphocyte numbers and BALF IgA to control group levels.

CONCLUSION

Fish oil infusion along with 5FU preserves GALT lymphocyte numbers and respiratory IgA levels.

Modulation of lipid rafts by Omega-3 fatty acids in inflammation and cancer: implications for use of lipids during nutrition support

Current understanding of biologic membrane structure and function is largely based on the concept of lipid rafts. Lipid rafts are composed primarily of tightly packed, liquid-ordered sphingolipids/cholesterol/saturated phospholipids that float in a sea of more unsaturated and loosely packed, liquid-disordered lipids. Lipid rafts have important clinical implications because many important membrane-signaling proteins are located within the raft regions of the membrane, and alterations in raft structure can alter activity of these signaling proteins. Because rafts are lipid-based, their composition, structure, and function are susceptible to manipulation by dietary components such as omega-3 polyunsaturated fatty acids and by cholesterol depletion. We review how alteration of raft lipids affects the raft/nonraft localization and hence the function of several proteins involved in cell signaling. We focus our discussion of raft-signaling proteins on inflammation and cancer.

Membrane-lipid therapy: a new approach in molecular medicine

Although most drugs bind to proteins and regulate their activity, some drugs act through a new therapeutic approach called membrane-lipid therapy and bind to lipids, thus modulating the structure of membranes. Most cellular functions are highly dependent on the lipid environment because they are controlled by proteins in or around membranes. The wide variety of cell and organelle membranes and the existence of special lipid regions (e.g. microvilli) and domains (e.g. lipid rafts) support the possibility of designing specific lipid therapies. Indeed, recent evidence suggests that lipid therapy might have potential for the treatment of cancer, cardiovascular pathologies, neurodegenerative processes, obesity, metabolic disorders, inflammation, and infectious and autoimmune diseases.

Docosahexaenoic acid (omega−3) blocks voltage-gated sodium channel activity and migration of MDA-MB-231 human breast cancer cells

Omega-3 polyunsaturated fatty acids have been suggested to play an important role in cancer prevention/progression, on the one hand, and in modulation of membrane ion channels on the other. We investigated whether docosahexaenoic acid would influence the in vitro migration of MDA-MB-231 human breast cancer cells. An important follow-up question was whether any effect would involve voltage-gated Na(+) channels, shown previously to occur in human breast cancer in vitro and in vivo and to correlate with metastatic potential. Short-term (acute) and long-term (24-72 h) application of docosahexaenoic acid suppressed the activity of the channel activity in a dose-dependent manner. At the working concentrations of docosahexaenoic acid used (0.05-0.5 microM), there was no effect on proliferation. Long-term treatment with docosahexaenoic acid down-regulated mRNA and protein (total and plasma membrane) levels of neonatal Nav1.5 voltage-gated Na(+) channel, known to be predominant in these cells. Docosahexaenoic acid suppressed migration of the MDA-MB-231 cells to the same extent as tetrodotoxin, a highly specific blocker of voltage-gated Na(+) channels, but the two effects were not additive. It was concluded that the docosahexaenoic acid-induced suppression of cellular migration occurred primarily via down-regulation of voltage-gated Na(+) channel (neonatal Nav1.5) mRNA and functional protein expression.

The repression of E2F-1 is critical for the activity of Minerval against cancer

The recently discovered anticancer drug Minerval (2-hydroxy-9-cis-octadecenoic acid) is a synthetic fatty acid that modifies the structure of the membrane. This restructuring facilitates the recruitment of protein kinase C (PKC) alpha to membranes and is associated with the antineoplastic activity of Minerval in cellular and animal models of cancer. Minerval is a derivative of oleic acid (OA) with an enhanced antiproliferative activity in human cancer cells and animal models of cancer, which is associated with PKCalpha activation and p21(CIP) overexpression. However, the signaling cascades involved in its pharmacological activity remain largely unknown. Here, we showed that this drug induced cell cycle arrest before entry into S phase, human lung adenocarcinoma (A549) cells accumulating in the G0/G1 phase. This cell cycle arrest was associated with a marked decrease in the expression of E2F-1. This transcription factor activates several cell cycle-related genes, and, accordingly, the expression of certain cyclins and cyclin-dependent kinases (cdks) was markedly lower upon exposure to Minerval. The reduced availability of these kinase heterodimers was associated with reduced phosphorylation of the retinoblastoma protein (pRb) observed after drug treatment. Significantly, hypophosphorylated pRb remains bound to E2F-1 and maintains this transcription factor inactive. The modulation of these antiproliferative mechanisms by Minerval explains its anticancer potency, through a new therapeutic strategy that can be used to develop new antitumor drugs. On the other hand, apoptosis did not seem to be involved in its pharmacological mechanism. Interestingly, whereas the changes induced by OA were only modest, they may reflect the beneficial effects of high olive oil intake against cancer.