Antiproliferative and proapoptotic effects of DODAC/synthetic phosphoethanolamine on hepatocellular carcinoma cells.

BACKGROUND: Current studies have demonstrated that DODAC/PHO-S (Dioctadecyldimethylammonium Chloride/Synthetic phosphoethanolamine) liposomes induces cytotoxicity in Hepa1c1c7 and B16F10 murine tumor cells, with a higher proportion than PHO-S. Therefore, our aim was to evaluate the potential of DODAC/PHO-S to elucidate the mechanism of cell death whereby the liposomes induces cytotoxicity in hepatocellular carcinoma Hepa1c1c7, compared to the PHO-S alone. METHODS: Liposomes (DODAC/PHO-S) were prepared by ultrasonication. The cell cycle phases, protein expression and types of cell's death on Hepa1c1c7 were analyzed by flow cytometry. The internalisation of liposomes, mitochondrial electrical potential and lysosomal stability were also evaluated by confocal laser scanning microscopy. RESULTS: After treatment with liposomes (DODAC/PHO-S), we observed a significant increase in the population of Hepa1c1c7 cells experiencing cell cycle arrest in the S and G2/M phases, and this treatment was significantly more effective to promote cell death by apoptosis. There also was a decrease in the mitochondrial electrical potential; changes in the lysosomes; nuclear fragmentation and catastrophic changes in Hepa1c1c7 cells. The liposomes additionally promoted increases in the expression of DR4 receptor, caspases 3 and 8, cytochrome c, p53, p21, p27 and Bax. There was also a decrease in the expression of Bcl-2, cyclin D1, CD90 and CD44 proteins. CONCLUSION: The overall results showed that DODAC/PHO-S liposomes were more effective than PHO-S alone, in promoting cytotoxicity Hepa1c1c7 tumor cells, activating the intrinsic and extrinsic pathways of programmed cell death.

Modulation of pro-apoptotic effects and mitochondrial potential on B16F10 cells by DODAC/PHO-S liposomes.

OBJECTIVE: We aimed to evaluate the potential of DODAC/PHO-S liposomes on the modulation of the expression of pro-apoptotic proteins, loss of lysosomal integrity and the mitochondrial electrical potential, compared with phosphoethanolamine. RESULTS: The results of this study demonstrate that DODAC/PHO-S liposomes have exhibited broad cytotoxic potential in B16F10 murine melanoma cells, with significantly greater proportions than treatment with PHO-S. The treatment with the DODAC/PHO-S 2.0 mM liposomal formulation was more efficient in decreasing mitochondrial electrical potential at the same concentrations and treatment time than PHO-S The liposomal formulation DODAC/PHO-S (2.0 mM) was more efficient to promote morphological changes in the cells, without presenting intact lysosomes, at the same time of treatment and concentration as PHO-S Our results demonstrated that the liposomal formulation increased DR4 receptor expression and activated caspases 8 and 3, resulting in the release of cytochrome c in B16F10 tumour cells, when compared to treatment with PHO-S The data obtained prove that the use of DODAC as carrier can maximize the cytotoxic effects of PHO-S This was demonstrated by the translocation of cytochrome c to the cytoplasm and activation of caspase-3 and 8, decreasing the mitochondrial electrical potential and generating morphological changes, in B16F10 cells.

Antiproliferative and proapoptotic effects of DODAC/synthetic phosphoethanolamine on hepatocellular carcinoma cells

Background: Current studies have demonstrated that DODAC/PHO-S (Dioctadecyldimethylammonium Chloride/Synthetic phosphoethanolamine) liposomes induces cytotoxicity in Hepa1c1c7 and B16F10 murine tumor cells, with a higher proportion than PHO-S. Therefore, our aim was to evaluate the potential of DODAC/PHO-S to elucidate the mechanism of cell death whereby the liposomes induces cytotoxicity in hepatocellular carcinoma Hepa1c1c7, compared to the PHO-S alone. Methods: Liposomes (DODAC/PHO-S) were prepared by ultrasonication. The cell cycle phases, protein expression and types of cell's death on Hepa1c1c7 were analyzed by flow cytometry. The internalisation of liposomes, mitochondrial electrical potential and lysosomal stability were also evaluated by confocal laser scanning microscopy. Results: After treatment with liposomes (DODAC/PHO-S), we observed a significant increase in the population of Hepa1c1c7 cells experiencing cell cycle arrest in the S and G2/M phases, and this treatment was significantly more effective to promote cell death by apoptosis. There also was a decrease in the mitochondrial electrical potential; changes in the lysosomes; nuclear fragmentation and catastrophic changes in Hepa1c1c7 cells. The liposomes additionally promoted increases in the expression of DR4 receptor, caspases 3 and 8, cytochrome c, p53, p21, p27 and Bax. There was also a decrease in the expression of Bcl-2, cyclin D1, CD90 and CD44 proteins. Conclusion: The overall results showed that DODAC/PHO-S liposomes were more effective than PHO-S alone, in promoting cytotoxicity Hepa1c1c7 tumor cells, activating the intrinsic and extrinsic pathways of programmed cell death.

Modulation of pro-apoptotic effects and mitochondrial potential on B16F10 cells by DODAC/PHO-S liposomes

Objective We aimed to evaluate the potential of DODAC/PHO-S liposomes on the modulation of the expression of pro-apoptotic proteins, loss of lysosomal integrity and the mitochondrial electrical potential, compared with phosphoethanolamine. Results The results of this study demonstrate that DODAC/PHO-S liposomes have exhibited broad cytotoxic potential in B16F10 murine melanoma cells, with significantly greater proportions than treatment with PHO-S. The treatment with the DODAC/PHO-S 2.0 mM liposomal formulation was more efficient in decreasing mitochondrial electrical potential at the same concentrations and treatment time than PHO-S The liposomal formulation DODAC/PHO-S (2.0 mM) was more efficient to promote morphological changes in the cells, without presenting intact lysosomes, at the same time of treatment and concentration as PHO-S Our results demonstrated that the liposomal formulation increased DR4 receptor expression and activated caspases 8 and 3, resulting in the release of cytochrome c in B16F10 tumour cells, when compared to treatment with PHO-S The data obtained prove that the use of DODAC as carrier can maximize the cytotoxic effects of PHO-S This was demonstrated by the translocation of cytochrome c to the cytoplasm and activation of caspase-3 and 8, decreasing the mitochondrial electrical potential and generating morphological changes, in B16F10 cells.

Antiproliferative and proapoptotic effects of DODAC/synthetic phosphoethanolamine on hepatocellular carcinoma cells

Background: Current studies have demonstrated that DODAC/PHO-S (Dioctadecyldimethylammonium Chloride/Synthetic phosphoethanolamine) liposomes induces cytotoxicity in Hepa1c1c7 and B16F10 murine tumor cells, with a higher proportion than PHO-S. Therefore, our aim was to evaluate the potential of DODAC/PHO-S to elucidate the mechanism of cell death whereby the liposomes induces cytotoxicity in hepatocellular carcinoma Hepa1c1c7, compared to the PHO-S alone. Methods: Liposomes (DODAC/PHO-S) were prepared by ultrasonication. The cell cycle phases, protein expression and types of cell's death on Hepa1c1c7 were analyzed by flow cytometry. The internalisation of liposomes, mitochondrial electrical potential and lysosomal stability were also evaluated by confocal laser scanning microscopy. Results: After treatment with liposomes (DODAC/PHO-S), we observed a significant increase in the population of Hepa1c1c7 cells experiencing cell cycle arrest in the S and G2/M phases, and this treatment was significantly more effective to promote cell death by apoptosis. There also was a decrease in the mitochondrial electrical potential; changes in the lysosomes; nuclear fragmentation and catastrophic changes in Hepa1c1c7 cells. The liposomes additionally promoted increases in the expression of DR4 receptor, caspases 3 and 8, cytochrome c, p53, p21, p27 and Bax. There was also a decrease in the expression of Bcl-2, cyclin D1, CD90 and CD44 proteins. Conclusion: The overall results showed that DODAC/PHO-S liposomes were more effective than PHO-S alone, in promoting cytotoxicity Hepa1c1c7 tumor cells, activating the intrinsic and extrinsic pathways of programmed cell death.

Modulation of pro-apoptotic effects and mitochondrial potential on B16F10 cells by DODAC/PHO-S liposomes

Objective We aimed to evaluate the potential of DODAC/PHO-S liposomes on the modulation of the expression of pro-apoptotic proteins, loss of lysosomal integrity and the mitochondrial electrical potential, compared with phosphoethanolamine. Results The results of this study demonstrate that DODAC/PHO-S liposomes have exhibited broad cytotoxic potential in B16F10 murine melanoma cells, with significantly greater proportions than treatment with PHO-S. The treatment with the DODAC/PHO-S 2.0 mM liposomal formulation was more efficient in decreasing mitochondrial electrical potential at the same concentrations and treatment time than PHO-S The liposomal formulation DODAC/PHO-S (2.0 mM) was more efficient to promote morphological changes in the cells, without presenting intact lysosomes, at the same time of treatment and concentration as PHO-S Our results demonstrated that the liposomal formulation increased DR4 receptor expression and activated caspases 8 and 3, resulting in the release of cytochrome c in B16F10 tumour cells, when compared to treatment with PHO-S The data obtained prove that the use of DODAC as carrier can maximize the cytotoxic effects of PHO-S This was demonstrated by the translocation of cytochrome c to the cytoplasm and activation of caspase-3 and 8, decreasing the mitochondrial electrical potential and generating morphological changes, in B16F10 cells.

Potential antitumor activity of novel DODAC/PHO-S liposomes.

In recent studies, we showed that synthetic phosphoethanolamine (PHO-S) has a great potential for inducing cell death in several tumor cell lines without damage to normal cells. However, its cytotoxic effect and selectivity against tumor cells could increase with encapsulation in cationic liposomes, such as dioctadecyldimethylammonium chloride (DODAC), due to electrostatic interactions between these liposomes and tumor cell membranes. Our aim was to use cationic liposomes to deliver PHO-S and to furthermore maximize the therapeutic effect of this compound. DODAC liposomes containing PHO-S (DODAC/PHO-S), at concentrations of 0.3-2.0 mM, prepared by ultrasonication, were analyzed by scanning electron microscopy (SEM) and dynamic light scattering. The cytotoxic effect of DODAC/PHO-S on B16F10 cells, Hepa1c1c7 cells, and human umbilical vein endothelial cells (HUVECs) was assessed by MTT assay. Cell cycle phases of B16F10 cells were analyzed by flow cytometry and the morphological changes by SEM, after treatment. The liposomes were spherical and polydisperse in solution. The liposomes were stable, presenting an average of ∼ 50% of PHO-S encapsulation, with a small reduction after 40 days. DODAC demonstrated efficient PHO-S delivery, with the lowest values of IC50% (concentration that inhibits 50% of the growth of cells) for tumor cells, compared with PHO-S alone, with an IC50% value of 0.8 mM for B16F10 cells and 0.2 mM for Hepa1c1c7 cells, and without significant effects on endothelial cells. The Hepa1c1c7 cells showed greater sensitivity to the DODAC/PHO-S formulation when compared to B16F10 cells and HUVECs. The use of DODAC/PHO-S on B16F10 cells induced G2/M-phase cell cycle arrest, with the proportion significantly greater than that treated with PHO-S alone. The morphological analysis of B16F10 cells by SEM showed changes such as "bleb" formation, cell detachment, cytoplasmic retraction, and apoptotic bodies after DODAC/PHO-S treatment. Cationic liposomal formulation for PHO-S delivery promoted cytotoxicity more selectively and effectively against B16F10 and Hepa1c1c7 cells. Thus, the DODAC/PHO-S liposomal formulation presents great potential for preclinical studies.

Castor oil polymer induces bone formation with high matrix metalloproteinase-2 expression.

The aim of this study was to evaluate the modulation of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) expression in newly formed bone tissue at the interface between implants derived from castor oil (Ricinus communis) polymer and the tibia medullary canal. Forty-four rabbits were assigned to either Group 1 (n = 12; control) or Group 2 (n = 30), which had the tibial medullary canals reamed bilaterally and filled with polymer. CT scans showed no space between the material surface and the bone at the implant/bone marrow interface, and the density of the tissues at this interface was similar to the density measured of other regions of the bone. At 90 days postimplantation, the interface with the polymer presented a thick layer of newly formed bone tissue rich in osteocytes. This tissue exhibited ongoing maturation at 120 and 150 days postimplantation. Overall, bone remodeling process was accompanied by positive modulation of MMP-2 and low MMP-9 expression. Differently, in control group, the internal surface close to the medullary canal was lined by osteoblasts, followed by a bone tissue zone with few lacunae filled with osteocytes. Maturation of the tissue of the medullary internal surface occurred in the inner region, with the bone being nonlamellar.

Synthetic phosphoethanolamine induces cell cycle arrest and apoptosis in human breast cancer MCF-7 cells through the mitochondrial pathway.

Phosphoethanolamine (Pho-s) is a compound involved in phospholipid turnover, acting as a substrate for many phospholipids of the cell membranes. In a recent study, we showed that Pho-s has antitumor effect in the several tumor cells. In this study we evaluated the antitumor activity of synthetic Pho-s on MCF-7 breast cancer cells. Here we demonstrate that Pho-s is cytotoxic to MCF-7 cells in a dose-dependent manner, while it is cytotoxic to MCF10 only at higher concentrations. In addition, Pho-s induces a disruption in mitochondrial membrane potential (Δψm). Furthermore, Pho-s induces mitochondria aggregates in the cytoplasm and DNA fragmentation of MCF-7 cells visualized by confocal microscopy. In agreement with the reduction on Δψm, we showed that Pho-s induces apoptosis followed by an increase in cytochrome c expression and capase-3-like activity in MCF-7 cells. Our results demonstrate that Pho-s induces a cell cycle arrest in the G1 phase through an inhibition of cyclin D1 and stimulates p53. An additional highlight of this study is the finding that Pho-s inhibits Bcl-2, inducing apoptosis through the mitochondrial pathway. Taken together, these results show that Pho-s is a promising compound in the fight against cancer.

Anti-angiogenic and anti-metastatic activity of synthetic phosphoethanolamine.

BACKGROUND: Renal cell carcinoma (RCC) is the most common type of kidney cancer, and represents the third most common urological malignancy. Despite the advent of targeted therapies for RCC and the improvement of the lifespan of patients, its cost-effectiveness restricted the therapeutic efficacy. In a recent report, we showed that synthetic phosphoethanolamine (Pho-s) has a broad antitumor activity on a variety of tumor cells and showed potent inhibitor effects on tumor progress in vivo. METHODOLOGY/PRINCIPAL FINDINGS: We show that murine renal carcinoma (Renca) is more sensitive to Pho-s when compared to normal immortalized rat proximal tubule cells (IRPTC) and human umbilical vein endothelial cells (HUVEC). In vitro anti-angiogenic activity assays show that Pho-s inhibits endothelial cell proliferation, migration and tube formation. In addition, Pho-s has anti-proliferative effects on HUVEC by inducing a cell cycle arrest at the G2/M phase. It causes a decrease in cyclin D1 mRNA, VEGFR1 gene transcription and VEGFR1 receptor expression. Pho-s also induces nuclear fragmentation and affects the organization of the cytoskeleton through the disruption of actin filaments. Additionally, Pho-s induces apoptosis through the mitochondrial pathway. The putative therapeutic potential of Pho-s was validated in a renal carcinoma model, on which our remarkable in vivo results show that Pho-s potentially inhibits lung metastasis in nude mice, with a superior efficacy when compared to Sunitinib. CONCLUSIONS/SIGNIFICANCE: Taken together, our findings provide evidence that Pho-s is a compound that potently inhibits lung metastasis, suggesting that it is a promising novel candidate drug for future developments.

Effect of ricinoleic acid esters from castor oil (Ricinus communis) on the oocyte yolk components of the tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae).

Rhipicephalus sanguineus are bloodsucking ectoparasites, whose main host is the domestic dog, thus being present in urban areas and closely located to people. Eventually, this tick species parasitize humans and can become a potential vector of infectious diseases. Methods to control this type of pest have been the focus of many research groups worldwide. The use of natural products is increasingly considered nowadays, due to the low toxicity levels to the host and low waste generation to the environment. This study tested the effect of ricinoleic acid esters from castor oil (as an potential acaricide) on the reproductive system of R. sanguineus females, more specifically on the vitellogenesis process. For this, two groups were established: the control group (CG) and the treatment group (TG) with five rabbits in each (New Zealand White), used as hosts. NaCl and ester were added to rabbits' food and offered to the hosts. After full engorgement, the females were collected and had their ovaries extracted. The ticks ovaries were submitted to histochemical techniques so the effects of esters could be observed over polysaccharides, proteins and lipids yolk. Changes in the deposition of yolk components were observed. This caused modifications on elements of polysaccharide origin and on glycoprotein compounds, interfering in the final yolk synthesis and compromising the development of the future embryo.

Synthetic phosphoethanolamine a precursor of membrane phospholipids reduce tumor growth in mice bearing melanoma B16-F10 and in vitro induce apoptosis and arrest in G2/M phase.

Phosphoethanolamine (Pho-s) is a compound involved in phospholipid turnover, acting as a substrate for many phospholipids of the cell membranes, especially phosphatidylcholine. We recently reported that synthetic Pho-s has potent effects on a wide variety of tumor cells. To determine if Pho-s has a potential antitumor activity, in this study we evaluated the activity of Pho-s against the B16-F10 melanoma both in vitro and in mice bearing a dorsal tumor. The treatment of B16F10 cells with Pho-s resulted in a dose-dependent inhibition of cell proliferation. At low concentrations, this activity appears to be involved in the arrest of the cell cycle at G2/M, while at high concentrations Pho-s induces apoptosis. In accordance with these results, the loss of mitochondrial potential and increased caspase-3 activity suggest that Pho-s has dual antitumor effects; i.e. it induces apoptosis at high concentrations and modulates the cell cycle at lower concentrations. In vivo, we evaluated the effect of Pho-s in mice bearing B16-F10 melanoma. The results show that Pho-s reduces the tumoral volume increasing survival rate. Furthermore, the tumor doubling time and tumor delays were substantially reduced when compared with untreated mice. Histological analyses reveal that Pho-s induces changes in cell morphology, typical characteristics of apoptosis, in addition the large areas of necrosis correlating with a reduction of tumor size. The results presented here support the hypothesis that Pho-s has antitumor effects by the induction of apoptosis as well as the inhibition of cell proliferation by arrest at G2/M. Thus, Pho-s can be regarded as a promising agent for the treatment of melanoma.

Anticancer effects of synthetic phosphoethanolamine on Ehrlich ascites tumor: an experimental study.

BACKGROUND: Antineoplastic phospholipids (ALPs) represent a promising class of drugs with a novel mode of action undergoes rapid turnover in the cell membrane of tumors, interfering with lipid signal transduction, inducing cell death. The aim of this study was to investigate the synthetic phosphoethanolamine (Pho-s) as a new anticancer agent. MATERIALS AND METHODS: Cell viability and morphology were assessed by (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Hoechst and rhodamine staining. Apoptosis was assessed by Annexin V and propidium iodide (PI) staining, caspase-3 activity, mitochondrial membrane potential (ΔmΨ) and cell cycle analysis, combined with evaluation of tumor growth in Ehrlich Ascites Tumor (EAT) bearing mice. RESULTS: We found that Pho-s 2.30 mg/ml induced cytotoxicity in all tumor cell lines studied without affecting normal cells. In vitro studies with EAT cells indicated that Pho-s induced apoptosis, demonstrated by an increase in Annexin-V positive cells, loss of mitochondrial potential (ΔmΨ) and increased caspase-3 activity. It was also shown to increase the sub-G(1) apoptotic fraction and inhibit progression to the S phase of the cell cycle. Additionally, antitumor effects on the EAT-bearing mice showed that Pho-s, at a concentration of 35 and 70 mg/kg, inhibited tumor growth and increased the lifespan of animals without causing liver toxicity. CONCLUSION: These findings suggest that Pho-s is a potential anticancer candidate drug.

Ultrastructural changes in the ovary cells of engorged Rhipicephalus sanguineus female ticks treated with esters of ricinoleic acid from castor oil (Ricinus communis).

Rhipicephalus sanguineus is a widely distributed tick species that has adapted to the urban environment, and the dog is its main host. This species is also known as a vector and reservoir of diseases caused by bacteria, protozoa, and viruses. Currently, acaricides of synthetic chemical origin have been widely and indiscriminately used, leading to the development of resistance to these products by ticks and causing damage to the environment. Thus, these issues have made it necessary to seek other forms of controlling these ectoparasites. R. sanguineus was artificially infested in host New Zealand White rabbits, which were divided into four treatment groups: control (CG1 and CG2) and treatment (TG1 and TG2) groups. TG1 and TG2 hosts were provided with feed supplemented with esters of ricinoleic acid from castor oil at a concentration of 5 g/kg of feed for 7 and 15 days. Afterward, the ovaries of the female ticks were removed for analysis by transmission electron microscopy. The results showed ultrastructural changes in the somatic and germ cells of ovaries from TG1 and TG2 females, particularly with respect to chorion deposition, a protective membrane of the oocyte, as well as in the transport process of vitellogenic materials via the hemolymph and pedicel cells. Moreover, the mitochondria were less electron-dense and had cristae that were more disorganized than the mitochondria from CG1 and CG2 individuals. Thus, this study demonstrated the action of esters on the ovaries of R. sanguineus, signaling the prospect of a way to control this ectoparasite without affecting nontarget organisms or the environment.

The effect of phosphoethanolamine intake on mortality and macrophage activity in mice with solid ehrlich tumors

The aim of the present study was to examine the effect of a diet rich in synthetic PEtn on the metabolism macrophages of tumor-bearing mice. The results demonstrated that PEtn increased the animals' survival time. In addition, the treated animals released smaller amounts of hydrogen peroxide (H2O2) and nitric oxide (NO) than the non-treated animals, particularly after day 14. From the results it could be concluded that H2O2 and NO were important in the modulation of neoplastic growth, and pointed to a promising role of PEtn in the control of human neoplasms.

Effects of Ricinus communis oil esters on salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae).

This study showed the interference of esters extracted from Ricinus communis in the secretory cycle of salivary glands of Rhipicephalus sanguineus ticks, which consequently caused collateral effects on their feeding process. Ticks attached on hosts which were fed with commercial feed containing different concentrations of R. communis oil esters suffered damages such as cytoplasmic changes in their salivary glands, notably in the acinar cells, impairing the functioning of the acini and accelerating the organs degeneration as a whole. It was found that esters interfered with the activity of cellular secretion by changing the glycoprotein of salivary composition especially in acini II cells. It was also shown that the damages caused by esters in the salivary glands cells of these ectoparasites increased in higher concentrations of the product and degenerative glandular changes were more pronounced.

Effects of ricinoleic acid esters from castor oil of Ricinus communis on the vitellogenesis of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) ticks.

This study examines the effects of ricinoleic acid esters from Ricinus communis castor oil on the vitellogenesis of Rhipicephalus sanguineus ticks attached to hosts that were fed with commercial rabbit food containing these esters. The oocytes of ticks from the treatment group (TG) showed cytoplasmic changes that inhibited the development of oocytes I and II to the advanced stages (IV and V) in addition to preventing the maturation of oocytes V, resulting in small ones. In addition, sperm was not observed in ampoules. Our findings confirm the acaricide potential of ricinoleic acid esters.

The effect of phosphoethanolamine intake on mortality and macrophage activity in mice with solid ehrlich tumors

The aim of the present study was to examine the effect of a diet rich in synthetic PEtn on the metabolism macrophages of tumor-bearing mice. The results demonstrated that PEtn increased the animals' survival time. In addition, the treated animals released smaller amounts of hydrogen peroxide (H2O2) and nitric oxide (NO) than the non-treated animals, particularly after day 14. From the results it could be concluded that H2O2 and NO were important in the modulation of neoplastic growth, and pointed to a promising role of PEtn in the control of human neoplasms.

Synthetic Phosphoethanolamine Induces Apoptosis Through Caspase-3Pathway by Decreasing Expression of Bax/Bad Protein and Changes CellCycle in Melanoma

Phospholipids are potential antineoplastic agents that are abundant constituents of the cell membrane ofeukaryotes and are supposed to be involved in specific intracellular signaling such as cell death. The aim of this study was to assess the in vitro and in vivo antitumor effects of synthetic phosphoethalomanine (PHO-S) on B16F10 murine melanoma cells and normal human fibroblasts. The cytotoxicty was evaluated by MTT assay and PHO-S was cytotoxic in melanoma cells but not in fibroblasts with IC50% of 1.4 mg/ml to melanoma cells. In vivo antitumor activity was evaluated in a mice model subcutaneously injected with B16F10 melanoma cells. The mice treated with PHO-S in all concentrations showed a decrease of the tumor growth and metastasis. Cytometry analysis showed that the PHO-S blocked DNA synthesis, decreased number of melanoma cells in S phase and G2/M, besides increasing number of apoptotic cells, inducing caspase-3 activity and decreasing Bad/Bax protein expression. Histologically, the dorsal tumors in the control group showed pigmented nodular masses with high vascularization and pleomorphictumor cells. In the treated group, PHO-S reduction vascularization intratumoral with increased of collagen fibersand infiltrates neutrophils. The data indicate that PHO-S is a lipid compound potential with proapoptotic andantiproliferative effects but further work will be necessary to elucidate the antitumor mechanisms.

Antiinflammatory activity of ricinus communis derived polymer

Aim: The present study aimed to evaluate the antiinflammatory activity of the polymer derived from Ricinus communis and its mechanism of action. Methods: The antiinflammatory activity was investigated in chronic and acute animal models and the mechanism of action involved in the antiinflammatory activity was determined by the in vitro phospholipase A2 (PLA2) enzyme assay. Results: In mouse ear edema (10.0 mg/ear) and granulomatous tissue formation (500 mg/kg) models, the polymer inhibited the inflammatory response in 75.08 ± 1.80% and 61.70 ± 1.80% of the cases, respectively (p<0.001). Oral administration of the Ricinus communis polymer (500 mg/kg) inhibited 72.00 ± 1.20% of formalin-induced inflammation. Topical administration of the polymer on oral lesions of mice showed that the oral mucosa was recovered in 60.00 ± 1.40% (p<0.05) of the cases. In in vitro assay, the phospholipase A2 enzyme was inhibited by the Ricinus communis polymer (5.0 mg/mL) in a dose-dependent manner (84.60 ± 1.41%). Conclusion: the polymer derived from Ricinus communis showed a significant antiinflammatory activity, confirming that the pharmacological mechanism involved in this antiinflammatory action was related to the inhibition of the PLA2 enzyme.