Debora Levy

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.

Detection of Plasmodium falciparum and Plasmodium vivax subclinical infection in non-endemic region: implications for blood transfusion and malaria epidemiology

BackgroundIn Brazil, malaria is endemic in the Amazon River basin and non-endemic in the extra-Amazon region, which includes areas of São Paulo state. In this state, a number of autochthonous cases of malaria occur annually, and the prevalence of subclinical infection is unknown. Asymptomatic infections may remain undetected, maintaining transmission of the pathogen, including by blood transfusion. In these report it has been described subclinical Plasmodium infection in blood donors from a blood transfusion centre in São Paulo, Brazil.MethodsIn this cross-sectional study, representative samples of blood were obtained from 1,108 healthy blood donors at the Fundação Pró-Sangue Hemocentro de São Paulo, the main blood transfusion centre in São Paulo. Malaria exposure was defined by the home region (exposed: forest region; non-exposed: non-forest region). Real-time PCR was used to detect Plasmodium falciparum and Plasmodium vivax. Subclinical malaria cases were geo-referenced.ResultsEighty-four (7.41%) blood donors tested positive for Plasmodium; 57 of these were infected by P. falciparum, 25 by P. vivax, and 2 by both. The prevalence of P. falciparum and P. vivax was 5.14 and 2.26, respectively. The overall prevalence ratio (PR) was 3.23 (95% confidence interval (CI) 2.03, 5.13); P. falciparum PR was 16.11 (95% CI 5.87, 44.21) and P. vivax PR was 0.47 (95% CI 0.2, 1.12). Plasmodium falciparum subclinical malaria infection in the Atlantic Forest domain was present in the mountain regions while P. vivax infection was observed in cities from forest-surrounded areas.ConclusionsThe presence of Plasmodium in healthy blood donors from a region known as non-endemic, which is important in the context of transfusion biosafety, was described. Infected recipients may become asymptomatic carriers and a reservoir for parasites, maintaining their transmission. Furthermore, P. falciparum PR was positively associated with the forest environment, and P. vivax was associated with forest fragmentation.

Mastoparan induces apoptosis in B16F10-Nex2 melanoma cells via the intrinsic mitochondrial pathway and displays antitumor activity in vivo

Mastoparan is an α-helical and amphipathic tetradecapeptide obtained from the venom of the wasp Vespula lewisii. This peptide exhibits a wide variety of biological effects, including antimicrobial activity, increased histamine release from mast cells, induction of a potent mitochondrial permeability transition and tumor cell cytotoxicity. Here, the effects of mastoparan in malignant melanoma were studied using the murine model of B16F10-Nex2 cells. In vitro, mastoparan caused melanoma cell death by the mitochondrial apoptosis pathway, as evidenced by the Annexin V-FITC/PI assay, loss of mitochondrial membrane potential (ΔΨm), generation of reactive oxygen species, DNA degradation and cell death signaling. Most importantly, mastoparan reduced the growth of subcutaneous melanoma in syngeneic mice and increased their survival. The present results show that mastoparan induced caspase-dependent apoptosis in melanoma cells through the intrinsic mitochondrial pathway protecting the mice against tumor development.

The Effect of Ursolic Acid on Leishmania (Leishmania) amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis

Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA) and oleanolic acid (OA) were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo). Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50) was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 μg/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 μg/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO) production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for the treatment of cutaneous leishmaniasis.

Interrelationship between ATP-binding cassette transporters and oxysterols

ATP-binding cassette (ABC) transporters constitute a ubiquitous superfamily of membrane proteins responsible for the translocation of several substances across membranes using the chemical energy provided by ATP hydrolysis. ABC transporters participate in many physiological and pathophysiological processes, including cholesterol and lipid transportation and multidrug resistance. Oxysterols are the products of cholesterol oxidation, formed by both enzymatic and non-enzymatic mechanisms. The role of oxysterols in cholesterol metabolism and several diseases has been widely investigated, but many questions remain to be answered. Several lines of evidence link ABC transporter functions with cholesterol and oxysterol metabolism. This review discusses ABC transporters, oxysterols, and how they interact with each other.

Short-term effects of 7-ketocholesterol on human adipose tissue mesenchymal stem cells in vitro.

Oxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and non-enzymatic oxidation. Among them, 7-ketocholesterol (7-KC) is one of the most important. It has potent effects in cell death processes, including cytoxicity and apoptosis induction. Mesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Very little is known about the effects of oxysterols in MSCs. Here, we describe the short-term cytotoxic effect of 7-ketocholesterol on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from two young, healthy women. After 24 h incubation with 7-KC, mitochondrial hyperpolarization was observed, followed by a slight increase in the level of apoptosis and changes in actin organization. Finally, the IC50 of 7-KC was higher in these cells than has been observed or described in other normal or cancer cell lines.

Apoptotic effect of eugenol envolves G2/M phase abrogation accompanied by mitochondrial damage and clastogenic effect on cancer cell in vitro.

BACKGROUND Eugenol (EUG) is a major phenolic compound present in clove whose anti-cancer properties have been demonstrated previously. These anti-cancer properties may involves the modulation of different mechanisms, including α-estrogen receptor (αER) in luminal breast cancer cells, COX-2 inhibition in melanoma cells or p53 and caspase-3 activation in colon cancer cells. HYPOTHESIS EUG promotes a burst in ROS production causing cell-cycle perturbations, mitochondria toxicity and clastogenesis triggering apoptosis in melanoma breast- and cervix-cancer cells in vitro. METHODS Morphological changes were evaluated through the light- and electronic- microscopy. Cell-cycle, ROS, PCNA and Apoptosis was detected by flow cytometry and clastogenicity was evaluated by Comet-assay. RESULTS The results obtained herein pointed out that EUG promotes, increasing ROS production leading to abrogation of G2/M of phase of cell-cycle, and consecutively, clastogenesis in vitro. In addition, EUG induces Proliferation Cell Nuclear Antigen (PCNA) downregulation and decreasing in mitochondria potential (ΔΨm). Of note, a Bax up-regulation was also observed on cells treated with EUG. All of these findings cooperate in order to induce apoptosis in cancer cells. CONCLUSION These promising results presented herein shed new light on the mechanisms of action of EUG suggesting a possible applicability of this phenylpropanoid as adjuvant in anti-cancer therapy.

Plasmodium falciparum in the southeastern Atlantic forest: a challenge to the bromeliad-malaria paradigm?

BackgroundRecently an unexpectedly high prevalence of Plasmodium falciparum was found in asymptomatic blood donors living in the southeastern Brazilian Atlantic forest. The bromeliad-malaria paradigm assumes that transmission of Plasmodium vivax and Plasmodium malariae involves species of the subgenus Kerteszia of Anopheles and only a few cases of P. vivax malaria are reported annually in this region. The expectations of this paradigm are a low prevalence of P. vivax and a null prevalence of P. falciparum. Therefore, the aim of this study was to verify if P. falciparum is actively circulating in the southeastern Brazilian Atlantic forest remains.MethodsIn this study, anophelines were collected with Shannon and CDC-light traps in seven distinct Atlantic forest landscapes over a 4-month period. Field-collected Anopheles mosquitoes were tested by real-time PCR assay in pools of ten, and then each mosquito from every positive pool, separately for P. falciparum and P. vivax. Genomic DNA of P. falciparum or P. vivax from positive anophelines was then amplified by traditional PCR for sequencing of the 18S ribosomal DNA to confirm Plasmodium species. Binomial probabilities were calculated to identify non-random results of the P. falciparum-infected anopheline findings.ResultsThe overall proportion of anophelines naturally infected with P. falciparum was 4.4% (21/480) and only 0.8% (4/480) with P. vivax. All of the infected mosquitoes were found in intermixed natural and human-modified environments and most were Anopheles cruzii (22/25 = 88%, 18 P. falciparum plus 4 P. vivax). Plasmodium falciparum was confirmed by sequencing in 76% (16/21) of positive mosquitoes, whereas P. vivax was confirmed in only 25% (1/4). Binomial probabilities suggest that P. falciparum actively circulates throughout the region and that there may be a threshold of the forested over human-modified environment ratio upon which the proportion of P. falciparum-infected anophelines increases significantly.ConclusionsThese results show that P. falciparum actively circulates, in higher proportion than P. vivax, among Anopheles mosquitoes of fragments of the southeastern Brazilian Atlantic forest. This finding challenges the classical bromeliad-malaria paradigm, which considers P. vivax circulation as the driver for the dynamics of residual malaria transmission in this region.

ABCB1, ABCC1, and LRP gene expressions are altered by LDL, HDL, and serum deprivation in a human doxorubicin-resistant uterine sarcoma cell line.

Multidrug resistance (MDR) is the major cause of cancer treatment failure. The ATP-binding cassette-B1 (ABCB1) transporter, also known as MDR1 or P-glycoprotein, is thought to promote the efflux of drugs from cells. MDR is also associated with the multidrug resistance-associated protein 1 (ABCC1) and the lung resistance-related protein (LRP), a human major vault protein. Moreover, MDR has a complex relationship with lipids. The ABCB1 has been reported to modulate cellular cholesterol homeostasis. Conversely, cholesterol has been reported to modulate multidrug transporters. However, results reported to date are contradictory and confusing. The aim of this study was to investigate whether LDL, HDL, and serum deprivation could influence ABCB1, ABCC1, and LRP expression in a human doxorubicin-resistant uterine sarcoma cell line. ABCB1 and ABCC1 expression increased after 24 h of serum deprivation, and expression returned to basal levels after 72 h. LDL, depending on concentration, increased ABCB1, ABCC1, and LRP expression. ABCB1 expression increased at low HDL, and decreased at high HDL concentrations. We demonstrated that serum deprivation and lipoproteins, particularly LDL, modulated ABCB1 expression and, to a lesser extent, ABCC1 expression. This finding may link the phenomena of drug transport, cholesterol metabolism and cancer.

The H/R FcγRIIA-131 polymorphism and survival in patients with diffuse large B-cell lymphoma (DLBCL) treated with R-CHOP: a study in a genetically mixed population

Non-Hodgkins lymphoma (NHL) comprises a heterogeneous group of cancers of the lymphoid system. The incidence of this disease is increasing worldwide. In Brazil, approximately 55,000 new cases are reported each year, and over 26,000 deaths result from NHL annually. In the state of Sao Paulo, the incidence is 12.2 cases per 100,000 inhabitants.1 B-cell lymphomas are the most common forms of NHL, and diffuse large B-cell lymphoma (DLBCL) is the most common subtype. The International Prognostic Index (IPI) is the primary clinical prognostic index used to classify individuals into different subgroups according to their DLBCL risk.