RESUMO

Breast cancer is the second leading contributor to the age-standardized mortality rate, for both sexes and all ages worldwide. In Europe and the United States, it is the second leading cause of mortality, with an incidence rate of about 2.6 million cases per year. Noscapine, a well-known alkaloid used as a cough suppressant, demonstrated anti-tumor effects by triggering apoptosis in various cancer cell lines and has the potential to become another ally against breast, ovarian, colon, and gastric cancer, among other types of malignancy. Apoptosis plays a crucial role in the treatment of cancer. Noscapine affected BAX, CASP8, CASP9, NFKBIA, and RELA gene and protein expression in the MCF-7 and MDA-MB-231 cell lines. Gene expression was higher in tumor than in normal tissue, including the BAX expression levels in lung, ovary, endometrium, colon, stomach, and glioblastoma patients; BCL2L1 expression in endometrium, colon, and stomach patients; CASP8 gene expression levels in lung, endometrium, colon, stomach, and glioblastoma patients; RELA in colon, stomach, and glioblastoma patients; and NFKBIA in glioblastoma patients. It can be concluded that noscapine affected genes and proteins related to apoptosis in cancer cell lines and several types of cancer patients.

Assuntos

RESUMO

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) represents a promising anticancer agent, as it selectively induces apoptosis in transformed cells without altering the cellular machinery of healthy cells. Unfortunately, the presence of TRAIL resistance mechanisms in a variety of cancer types represents a major hurdle, thus limiting the use of TRAIL as a single agent. Accumulating studies have shown that TRAIL-mediated apoptosis can be facilitated in resistant tumors by combined treatment with antitumor agents, ranging from synthetic molecules to natural products. Among the latter, flavonoids, the most prevalent polyphenols in plants, have shown remarkable competence in improving TRAIL-driven apoptosis in resistant cell lines as well as tumor-bearing mice with minimal side effects. Here, we summarize the molecular mechanisms, such as the upregulation of death receptor (DR)4 and DR5 and downregulation of key anti-apoptotic proteins [e.g., cellular FLICE-inhibitory protein (c-FLIP), X-linked inhibitor of apoptosis protein (XIAP), survivin], underlying the TRAIL-sensitizing properties of different classes of flavonoids (e.g., flavones, flavonols, isoflavones, chalcones, prenylflavonoids). Finally, we discuss limitations, mainly related to bioavailability issues, and future perspectives regarding the clinical use of flavonoids as adjuvant agents in TRAIL-based therapies.

Assuntos

RESUMO

Brazilin possesses anticancer effects, but the mechanisms are poorly understood. This study investigated the mechanisms of brazilin-induced cell death in the T24 human bladder cancer cell line. Low serum cell culture and the lactate dehydrogenase assay were used to confirm the antitumor effect of brazilin. Annexin V and propidium iodide double staining, transmission electron microscopy, fluo-3-AM assay for Ca2+ mobilization and caspase activity assay were performed to identify the type of cell death after brazilin treatment. Mitochondria membrane potentials were measured using JC-1. Quantitative real-time polymerase chain reaction and western blot analyses were performed to verify the expression of the necroptosis-related genes and proteins receptor interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain-like (MLKL). The results showed that brazilin induced necrosis in T24 cells and upregulated the mRNA and protein levels of RIP1, RIP3 and MLKL and Ca2+ influx. The necroptosis-mediated cell death was rescued by the necroptosis inhibitor necrostatin-1 (Nec-1), but not by the apoptosis inhibitor z-VAD-fmk. Brazilin repressed caspase 8 expression and decreased the mitochondrial membrane potentials; both effects were partially reversed by Nec-1. Brazilin induced physiological and morphological changes in T24 cells and RIP1/RIP3/MLKL-mediated necroptosis might be involved. In conclusion, the results confirm the involvement of necroptosis in brazilin-induced cell death and suggest that brazilin could be explored as an anticancer agent against bladder cancer.

Assuntos

RESUMO

Programmed cell death (PCD) is an important mechanism of innate immunity against bacterial pathogens. The innate immune PCD pathway involves the molecules caspase-7 and caspase-8, among others. Brucella abortus is a gram-negative bacterium that causes a zoonotic disease termed brucellosis. The innate immune response against this pathogen involves activation of inflammasome components and induction of pyroptosis. However, no studies so far have revealed the role of caspase-7 or caspase-8 during this bacterial infection. Herein, we demonstrate that caspase-7 is dispensable for caspase-1 processing, IL-1ß secretion and cell death in macrophages. Additionally, caspase-7 deficient animals control B. abortus infection as well as the wild type mice. Furthermore, we addressed the role of caspase-8 in inflammasome activation and pyroptosis during this bacterial infection. Macrophages deficient in caspase-8 secreted reduced amounts of IL-1ß that parallels with diminished caspase-1 activity when compared to wild type cells. Additionally, caspase-8 KO macrophages showed reduced LDH release when compared to wild type, suggesting that caspase-8 may play an important role in pyroptosis in response to B. abortus. Finally, caspase-8 KO animals were more susceptible to Brucella infection when compared to wild type mice. Overall, this study contributes to a better understanding of the involvement of caspase-7 and caspase-8 in innate immunity against B. abortus infection.

RESUMO

Inflammasomes are multiprotein complexes with an important role in the innate immune response. Canonical activation of inflammasomes results in caspase-1 activation and maturation of cytokines interleukin-1ß and -18. These cytokines can elicit their effects through receptor activation, both locally within a certain tissue and systemically. Animal models of kidney diseases have shown inflammasome involvement in inflammation, pyroptosis and fibrosis. In particular, the inflammasome component nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) and related canonical mechanisms have been investigated. However, it has become increasingly clear that other inflammasome components are also of importance in kidney disease. Moreover, it is becoming obvious that the range of molecular interaction partners of inflammasome components in kidney diseases is wide. This review provides insights into these current areas of research, with special emphasis on the interaction of inflammasome components and redox signalling, endoplasmic reticulum stress, and mitochondrial function. We present our findings separately for acute kidney injury and chronic kidney disease. As we strictly divided the results into preclinical and clinical data, this review enables comparison of results from those complementary research specialities. However, it also reveals that knowledge gaps exist, especially in clinical acute kidney injury inflammasome research. Furthermore, patient comorbidities and treatments seem important drivers of inflammasome component alterations in human kidney disease.

RESUMO

Eleutherine plicata has been shown to be a promising medicinal plant, and its activity has been associated with naphthoquinones. The present study aimed at evaluating the cytotoxicity, genotoxicity, and oral toxicity of the ethanol extract (EEEp), dichloromethane fraction (FDMEp) of E. plicata, and isoeleutherin. For the cytotoxicity evaluation, the viability test (MTT) was used. Genotoxicity was accessed through the Comet assay (alkaline version), acute and subacute oral toxicities were also evaluated. The antioxidant capacity of the samples in the wells where the cells were treated with E. plicata was evaluated. Furthermore, the participation of caspase-8 in the possible mechanism of action of isoeleutherin, eleutherin, and eleutherol was also investigated through a docking study. FDMEp and isoeleutherin were cytotoxic, with higher rates of DNA fragmentation observed for FDMEp and isoeleutherin, and all samples displayed higher antioxidant potential than the control. In the acute oral toxicity test, EEEp, FDMEp, and isoeleutherin did not cause significant clinical changes. In the subacute toxicity assay, EEEp and FDMEp also did not cause clinical, hematological, or biochemical changes. The three compounds bound similarly to caspase-8. Despite the results of cytotoxicity, in vitro studies demonstrated that the use of EEEp appears to be safe and cell death may involve its binding to caspase-8.

RESUMO

ABSTRACT PURPOSE: We examined the effect of intracameral administration of cefuroxime on oxidative stress and endothelial apoptosis in rat corneal tissue. METHODS: In total, 30 rats were divided into 3 groups of 10 rats each (intracameral administration of cefuroxime 0.1 mg/0.01 mL (cefuroxime group); intracameral administration of balanced salt solution 0.01 mL (control group); or absence of intracameral injection (sham group). Corneal endothelial apoptosis was assessed by immunohistochemical analysis using caspase-3 and caspase-8. Total oxidant status, total antioxidant status, oxidative stress index, and paraoxonase and arylesterase levels were examined in corneal endothelial tissue and serum. RESULTS: Paraoxonase levels in the serum were significantly different between the sham and cefuroxime groups (p=0.027). A significant difference was also observed in total oxidant status levels between the cefuroxime and balanced salt solution groups (p=0.023). In addition, there were significant differences in total antioxidant status levels in corneal tissue between the cefuroxime and sham groups (p<0.001) and between the cefuroxime and balanced salt solution groups (p<0.001). Furthermore, significant differences were also observed in oxidative stress index levels between the cefuroxime and balanced salt solution groups (p=0.001) and between the cefuroxime and sham groups (p=0.026). According to the immunohistochemical staining results, a significant association with caspase-3 activity existed between the cefuroxime and balanced salt solution groups (p=0.007), while no significant difference was found with caspase-8 activity (p=0.541). Caspase-3 activity exhibited a significant relationship between the sham and balanced salt solution groups (p=0.018), but no relationship was found with caspase-8 activity (p=0.623). CONCLUSION: Immunohistochemical examination revealed that intracameral cefuroxime increased apoptosis when compared to the sham and balanced salt solution groups. Moreover, intracameral cefuroxime increased oxidative stress in the cornea and simultaneously induced apoptosis.

RESUMO OBJETIVO: Examinamos o efeito da administração intracameral da cefuroxima sobre o estresse oxidativo e a apoptose endotelial no tecido corneano de ratos. MÉTODOS: No total, 30 ratos foram divididos em 3 grupos de 10 ratos cada (administração intracameral de cefuroxima 0,1 mg/0,01 mL (grupo cefuroxima), administração intracameral de solução salina balanceada 0,01 mL (grupo controle) ou ausência de injeção intracameral (grupo sham)). A apoptose endotelial da córnea foi avaliada por análise imuno-histoquimica usando caspase-3 e -8. O status oxidante total, o status antioxidante total, o índice de estresse oxidativo e os níveis de a paraoxonase e arilesterase foram investigados no tecido endotelial da córnea e no soro. RESULTADOS: Os níveis de paraoxonase no soro foram significativamente diferentes entre os grupos sham e cefuroxima (p=0,027). Foi também observada uma diferença significativa nos níveis de estado oxidante total entre os grupos cefuroxima e solução salina balanceada (p=0,023). Além disso, houve diferenças significativas nos níveis de status antioxidante total no tecido da córnea entre os grupos cefuroxima e sham (p<0,001) e entre os grupos cefuroxima e solução salina balanceada (p<0,001). Diferenças significativas também foram observadas nos níveis do índice de estresse oxidativo entre os grupos cefuroxima e solução salina balanceada (p=0,001) e entre os grupos cefuroxima e sham (p=0,026). De acordo com os resultados de coloração imuno-histoquimica, houve associação significativa com a atividade da caspase-3 entre os grupos cefuroxima e solução salina balanceada (p=0,007), enquanto não houve diferença significativa com a atividade da caspase-8 (p=0,541). A atividade da caspase-3 exibiu uma relação significativa entre os grupos sham e solução salina balanceada (p=0,018), mas nenhuma relação foi encontrada com a atividade da caspase-8 (p=0,623). CONCLUSÃO: O exame imuno-histoquímico revelou que a cefuroxima intracameral aumentou a apoptose quando comparada com os grupos sham e solução salina balanceada. Além disso, a cefuroxima intracameral aumentou o estresse oxidativo na córnea e induziu simultaneamente a apoptose.

Assuntos

RESUMO

Environmental factors during perinatal life can lead to changes in the mammary gland, making it susceptible to cancer in adulthood. Breastfeeding has a special importance since it takes place at a critical period of growth and development of the newborn. We aimed to analyze if an appropriate lactation protects the offspring against mammary carcinogenesis during adult life and explore the mechanisms involved in the protective effect. One-day-old Sprague-Dawley female rats were randomly distributed in litters of three (L3), eight (L8) or 12 (L12) pups per dam, to induce a differential consumption of breast milk. At 55 days of age, the animals were treated with a single dose of dimethylbenzanthracene to study tumor latency, incidence and progression. Histological, immunohistochemical and Western blot studies were performed. We observed lower incidence and higher latency in L3 compared to the other groups. The mitotic index and expression of proliferating cell nuclear antigen (PCNA) was significantly augmented in tumors of L12 rats compared to L3 and L8, while the apoptotic index was augmented in tumors of L3 v. L12. Cleaved caspase 8 was significantly higher in tumors from L3 compared to L12. Tumors developed in L3 have a greater number of apoptotic bodies and a greater expression of caspase 8. These results demonstrate that the animals that maintained a higher intake of maternal milk (L3) presented lower incidence and greater tumor latency. Lower consumption of breast milk (L12) would increase tumor mitosis and the expression of PCNA, explaining the higher tumor incidence observed in this group.

Assuntos

RESUMO

Granulosa cells control oocyte maturation through paracrine signalling and changes to the microenvironment around the oocyte. Apoptosis occurs as a physiological mechanism of granulosa cell renewal, but how it relates with the ovarian response to induced ovulation is still unclear. Therefore, this study evaluated apoptosis-related gene expression levels in granulosa cells of patients undergoing controlled ovarian stimulation. We enrolled prospectively 59 consecutive IVF patients referred to a tertiary academic hospital for couple infertility treatment. Luteinized granulosa cells were isolated from follicular fluid and the RNA was extracted, reverse-transcribed and the gene expression of apoptosis inducers (caspase-3, caspase-8 and bax) and inhibitor (Bcl-2) was quantified by real-time polymerase chain reaction. Caspase-3 gene expression correlated negatively with the number of pre-ovulatory follicles (Spearman's r = -0.308), the number of collected oocytes (r = -0.451), the number of mature oocytes (r = -0.526), the number of fertilized oocytes (r = -0.439) and the number of viable embryos (r = -0.443, all statistically significant at p < 0.02 level). No such associations were found with caspase-8, bax or bcl-2. These preliminary findings suggest that increased caspase-3 gene expression in granulosa cells is associated with a worse ovulatory response in humans.

Assuntos

RESUMO

Necroptosis is a pro-inflammatory cell death, which happens in the context of caspase-8 inhibition, allowing activation of the receptor interacting protein kinase 1-receptor interacting protein kinase 3-mixed lineage kinase domain-like (RIPK1-RIPK3-MLKL) axis. Recently, necroptosis has emerged as a key component of resistance against pathogens including infected macrophage by Leishmania infantum, the ethiologic agent of Visceral leishmaniasis (VL). VL is the most severe form of Leishmaniasis, characterized by systemic inflammation and neutropenia. However, the role of neutrophil cell death in VL has not been characterized. Here, we showed that VL patients exhibited increased lactate dehydrogenase levels in the serum, a hallmark of cell death and tissue damage. We investigated the effect of necroptosis in neutrophil infection in vitro. Human neutrophils pretreated with zVAD-fmk (pan-caspase inhibitor) and zIETD-fmk (caspase-8 inhibitor) increased reactive oxygen species (ROS) level in response to Leishmania infection, which is associated with necroptotic cell death. MLKL, an important effector molecule downstream of necroptosis pathway, was also required for Leishmania killing. Moreover, in absence of caspases-8, murine neutrophils displayed loss of membrane integrity, higher levels of ROS, and decreased L. infantum viability. Pharmacological inhibition of RIPK1 or RIPK3 increased parasite survival when caspase-8 was blocked. Electron microscopy assays revealed morphological features associated with necroptotic death in L. infantum infected-neutrophils pretreated with caspase inhibitor, whereas infected cells pretreated with RIPK1 and RIPK3 inhibitors did not show ultra-structural alterations in membrane integrity and presented viable Leishmania within parasitophorous vacuoles. Taken together, these findings suggest that inhibition of caspase-8 contributes to elimination of L. infantum in neutrophils by triggering necroptosis. Thus, targeting necroptosis may represent a new strategy to control Leishmania replication.

Assuntos

RESUMO

Background: Paracoccidioides brasiliensis is equipped with an arsenal of virulence factors that are crucial for causing infection. Our group previously defined the NLRP3 inflammasome as a mediator of P brasiliensis-induced cell damage recognition and induction of effective Th1 immune responses. However, deficiency of caspase-1 only partially reduced interleukin (IL)-1ß levels. Methods: In this study, using chemical inhibitors as well as genetically modified mice, we identify an additional pathway for IL-1ß production in response to P brasiliensis infection. Results: Paracoccidioides brasiliensis initiated caspase-8-mediated IL-1ß production, an event that was necessary for transcriptional priming and posttranslational processing of pro-IL-1ß. Caspase-8 synergizes with the canonical NLRP3 inflammasome pathway to control caspase-1 processing and IL-1ß maturation, providing a regulatory role for caspase-8 in host resistance to in vivo P brasiliensis infection. Conclusions: Taken together, these findings revealed an important role for caspase-8 in the innate immune response of host cells to P brasiliensis infection, demonstrating a connected network between noncanonical and canonical inflammasomes to coordinate IL-1ß production during fungal challenge.

Assuntos

RESUMO

BACKGROUND: Preeclampsia is responsible for considerable mortality and morbidity of mother and sibling. The etiology of preeclampsia is still unknown. Family studies indicate the involvement of genes located on chromosome 2 in preeclampsia development. Considering the importance of apoptosis and chromosome 2, one promising candidate for the study of the genetic cause of this syndrome is the CASPASE-8 gene, which was chosen as the subject of this study. OBJECTIVE: The aim of this study was to determine the frequencies of the genotypes for CASP8 gene polymorphisms (rs13416436 and rs2037815) and to associate these with preeclampsia development in Brazilian women. METHODS: Women with and without preeclampsia were investigated. Accordingly, peripheral blood was collected and DNA extracted, followed by genotyping using Real-time PCR with hydrolysis probe (Taqman® Life Technologies). RESULTS: The results showed no association between genotypes and preeclampsia development for both polymorphisms studied (χ2 = 1.03; p = 0.59, for rs13416436 and χ2 = 1.06; p = 0.58 for rs2037815). CONCLUSIONS: It seems that CASP8 gene polymorphisms (rs13416436 and rs2037815) are not important candidates for the development of preeclampsia. Other genes related to the apoptosis process or other polymorphisms in this gene should be studied in order to understand better the etiology of preeclampsia.

Assuntos

RESUMO

Cardiomyocyte apoptosis plays key roles in the pathogenesis of heart diseases such as myocardial infarction. MicroRNAs are important regulators of gene expression, which are also involved in the regulation of cardiomyocyte apoptosis. However, cardiomyocyte apoptosis regulated by microRNA (miR)-122 is largely unexplored. The aim of this study focused on the role of miR-122 in cardiomyocyte apoptosis. Cardiomyocytes were isolated from neonatal mice and primarily cultured. MiR-122 mimic and inhibitor were transfected to cardiomyocytes and verified by qRT-PCR. Cell viability and apoptosis post-transfection were assessed by MTT assay and flow cytometry, respectively. Changes in expression of caspase-8 were quantified by qRT-PCR and western blot. Results showed that miR-122 mimic and inhibitor successfully induced changes in miR-122 levels in cultured cardiomyocytes (P<0.01). MiR-122 overexpression suppressed viability and promoted apoptosis of cardiomyocytes (P<0.05), and miR-122 knockdown promoted cell viability and inhibited apoptosis (P<0.05). The mRNA and protein levels of caspase-8 were elevated by miR-122 overexpression (P<0.01) and reduced by miR-122 knockdown (P<0.001). These results suggest an inductive role of miR-122 in cardiomyocyte apoptosis, which may be related to its regulation on caspase-8.

Assuntos

RESUMO

BIRM is an anticancer herbal formulation from Ecuador. Previous study established its antitumor and antimetastatic activity against prostate cancer models. The activity of BIRM against human prostate cancer (PCa) cells was investigated to uncover its mechanism of antitumor activity. In androgen receptor (AR)-expressing PCa cells BIRM was 2.5-fold (250%) more cytotoxic in presence of androgen (DHT) compared to cells grown in the absence of DHT. In AR-positive cells (LAPC-4 and LNCaP) BIRM caused a dose and time-dependent down-regulation of AR and increased apoptosis. Exposing cells to BIRM did not affect the synthesis of AR and AR promoter activity but increased degradation of AR via proteasome-pathway. BIRM caused destabilization of HSP90-AR association in LAPC-4 cells. It induced apoptosis in PCa cells by activation of caspase-8 via death receptor and FADD-mediated pathways. A synthetic inhibitor of Caspase-8 cleavage (IETD-CHO) aborted BIRM-induced apoptosis. The effect of BIRM on AKT-mediated survival pathway in both AR+ and AR- negative (PC-3 and DU145) showed decreased levels of p-AKTser 473 in all PCa cell lines. BIRM dosed by oral gavage in mice bearing PC-3ML tumors showed selective efficacy on tumor growth; before tumors are established but limited efficacy when treated on existing tumors. Moreover, BIRM inhibited the LNCaP tumor generated by orthotropic implantation into dorsal prostate of nude mice. Partial purification of BIRM by liquid-liquid extraction and further fractionation by HPLC showed 4-fold increased specific activity on PCa cells. These results demonstrate a mechanistic basis of anti-tumor activity of the herbal extract BIRM.

Assuntos

RESUMO

Congenital Chagas disease is caused by the protozoan parasite Trypanosoma cruzi that must cross the placental barrier during transmission. The trophoblast constitutes the first tissue in contact with the maternal-blood circulating parasite. Importantly, the congenital transmission rates are low, suggesting the presence of local placental defense mechanisms. Cellular proliferation and differentiation as well as apoptotic cell death are induced by the parasite and constitute part of the epithelial turnover of the trophoblast, which has been suggested to be part of those placental defenses. On the other hand, caspase-8 is an essential molecule in the modulation of trophoblast turnover by apoptosis and by epithelial differentiation. As an approach to study whether T. cruzi induced trophoblast turnover and infection is mediated by caspase-8, we infected BeWo cells (a trophoblastic cell line) with the parasite and determined in the infected cells the expression and enzymatic activity of caspase-8, DNA synthesis (as proliferation marker), ß-human chorionic gonadotropin (ß-hCG) (as differentiation marker) and activity of Caspase-3 (as apoptotic death marker). Parasite load in BeWo cells was measured by DNA quantification using qPCR and cell counting. Our results show that T. cruzi induces caspase-8 activity and that its inhibition increases trophoblast cells infection while decreases parasite induced cellular differentiation and apoptotic cell death, but not cellular proliferation. Thus, caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against T. cruzi infection. Together with our previous results, we suggest that the trophoblast turnover is part of local placental anti-parasite mechanisms.

Assuntos

RESUMO

A liberação da placenta após o parto envolve a perda da adesão materno-fetal e ocorre somente após a maturação completa do placentoma, que está relacionada com a diminuição da celularidade dos tecidos fetal e materno. A apoptose é requerida tanto para a maturação quanto para a liberação normal da placenta após o parto. O objetivo do presente estudo foi avaliar a ocorrência de apoptose em amostras de placenta de vacas em diferentes fases de gestação. Amostras de placentomas de 15 vacas saudáveis com 4 (n=5), 6 (n=5) e 9 (n=5) meses de gestação foram colhidas e processadas rotineiramente para a histologia, imunoistoquímica e histoquímica. As lâminas obtidas foram coradas em HE, Picrosirius Red e submetidas à análise imunoistoquímica das proteínas Caspase 3, Caspase 8, Bax e Bid. O aumento no número de vasos não necessariamente se associou ao aumento do calibre destes durante a evolução da gestação. Os resultados de histomorfometria revelaram aumento da marcação para Bax e Caspases 3 e 8 em células trofoblásticas binucleadas no final da gestação, enquanto o Bid se manteve sem alteração significativa. A histomorfometria das células trofoblásticas mononucleadas revelou expressão alta para Bax no início de gestação, com diminuição aos 6 meses de gestação e aumento das imunomarcações para Caspases 3 e 8, e Bid com o avanço gestacional. Os colágenos tipo I e III não aumentaram do terço médio ao final da gestação, o que é importante para a diminuição da adesão materno-fetal. Esses resultados confirmam que as Caspases 3 e 8, e o Bax estão envolvidos nos mecanismos de ativação da apoptose pela via intrínseca mitocondrial e/ou extrínseca ao longo da gestação em células trofoblásticas binucleadas, e que nas células trofoblásticas mononucleadas o Bax deixa de ser importante, enquanto o Bid e as Caspases 3 e 8 se tornam os mais significativos.

Placental release after birth involves loss of maternal-fetal adhesion and occurs only after complete maturation of the placentoma related to the decrease in cellularity of fetal and maternal tissues. Apoptosis is required for both the normal maturation and release of the placenta after birth. The aim of this study was to evaluate the occurrence of apoptosis in samples of the placenta of cows in different stages of gestation. Samples of 15 healthy cow placentomas at 4 (n=5), 6 (n=5) and 9 (n=5) months of gestation were harvested and processed for routine histology, immunohistochemistry and histochemistry. The slides were stained with HE, PicroSirius Red and subjected to immunohistochemical analysis of proteins Caspase 3, Caspase 8, Bax and Bid. Increase in number of vessels was not associated with increase in vascular area during progression of gestation. The results of histomorphometry revealed increased labeling for Bax and Caspases 3 and 8 in trophoblastic binucleated cells in late pregnancy, where the Bid remained without significant change. Histomorphometry analyzing the mononuclear trophoblast cells showed a high expression for Bax in early pregnancy, but decreased at 6 months of gestation. Immunolabeling revealed increased Caspases 3/8 and Bid with advancing of gestation. Further evaluation of type I and III collagen showed a decrease of both types of collagens at the end of gestation, what is very important for the reduction of maternal-fetal adhesion. These results confirm that Caspases 3 and 8 and Bax are involved in the mechanisms of activation of apoptosis through mitochondrial intrinsic and/or extrinsic pathway during pregnancy in trophoblastic binucleated cells. In mononuclear trophoblast cells Bax looses importance in the apoptosis process, awhile Bid and caspases 3 and 8 become the most significant.

Assuntos

RESUMO

A liberação da placenta após o parto envolve a perda da adesão materno-fetal e ocorre somente após a maturação completa do placentoma, que está relacionada com a diminuição da celularidade dos tecidos fetal e materno. A apoptose é requerida tanto para a maturação quanto para a liberação normal da placenta após o parto. O objetivo do presente estudo foi avaliar a ocorrência de apoptose em amostras de placenta de vacas em diferentes fases de gestação. Amostras de placentomas de 15 vacas saudáveis com 4 (n=5), 6 (n=5) e 9 (n=5) meses de gestação foram colhidas e processadas rotineiramente para a histologia, imunoistoquímica e histoquímica. As lâminas obtidas foram coradas em HE, Picrosirius Red e submetidas à análise imunoistoquímica das proteínas Caspase 3, Caspase 8, Bax e Bid. O aumento no número de vasos não necessariamente se associou ao aumento do calibre destes durante a evolução da gestação. Os resultados de histomorfometria revelaram aumento da marcação para Bax e Caspases 3 e 8 em células trofoblásticas binucleadas no final da gestação, enquanto o Bid se manteve sem alteração significativa. A histomorfometria das células trofoblásticas mononucleadas revelou expressão alta para Bax no início de gestação, com diminuição aos 6 meses de gestação e aumento das imunomarcações para Caspases 3 e 8, e Bid com o avanço gestacional. Os colágenos tipo I e III não aumentaram do terço médio ao final da gestação, o que é importante para a diminuição da adesão materno-fetal. Esses resultados confirmam que as Caspases 3 e 8, e o Bax estão envolvidos nos mecanismos de ativação da apoptose pela via intrínseca mitocondrial e/ou extrínseca ao longo da gestação em células trofoblásticas binucleadas, e que nas células trofoblásticas mononucleadas o Bax deixa de ser importante, enquanto o Bid e as Caspases 3 e 8 se tornam os mais significativos.(AU)

Placental release after birth involves loss of maternal-fetal adhesion and occurs only after complete maturation of the placentoma related to the decrease in cellularity of fetal and maternal tissues. Apoptosis is required for both the normal maturation and release of the placenta after birth. The aim of this study was to evaluate the occurrence of apoptosis in samples of the placenta of cows in different stages of gestation. Samples of 15 healthy cow placentomas at 4 (n=5), 6 (n=5) and 9 (n=5) months of gestation were harvested and processed for routine histology, immunohistochemistry and histochemistry. The slides were stained with HE, PicroSirius Red and subjected to immunohistochemical analysis of proteins Caspase 3, Caspase 8, Bax and Bid. Increase in number of vessels was not associated with increase in vascular area during progression of gestation. The results of histomorphometry revealed increased labeling for Bax and Caspases 3 and 8 in trophoblastic binucleated cells in late pregnancy, where the Bid remained without significant change. Histomorphometry analyzing the mononuclear trophoblast cells showed a high expression for Bax in early pregnancy, but decreased at 6 months of gestation. Immunolabeling revealed increased Caspases 3/8 and Bid with advancing of gestation. Further evaluation of type I and III collagen showed a decrease of both types of collagens at the end of gestation, what is very important for the reduction of maternal-fetal adhesion. These results confirm that Caspases 3 and 8 and Bax are involved in the mechanisms of activation of apoptosis through mitochondrial intrinsic and/or extrinsic pathway during pregnancy in trophoblastic binucleated cells. In mononuclear trophoblast cells Bax looses importance in the apoptosis process, awhile Bid and caspases 3 and 8 become the most significant.(AU)

Assuntos

RESUMO

The HPV-16 E6 and E6(⁎) proteins have been shown previously to be capable of regulating caspase 8 activity. We now show that the capacity of E6 to interact with caspase 8 is common to diverse HPV types, being also seen with HPV-11 E6, HPV-18 E6 and HPV-18 E6(⁎). Unlike most E6-interacting partners, caspase 8 does not appear to be a major proteasomal target of E6, but instead E6 appears able to stimulate caspase 8 activation, without affecting the overall apoptotic activity. This would appear to be mediated in part by the ability of the HPV E6 oncoproteins to recruit active caspase 8 to the nucleus.

Assuntos

RESUMO

Despite impressive research efforts, the biology of epithelial ovarian cancer (EOC) remains poorly understood and alterations in the expression of CASPASE-8 contribute to a worse tumor prognosis. This study assesses the methylation of the CpG island within the CASPASE-8 promoter and CASPASE-8 gene expression both in cystadenoma tumors and in primary and metastatic EOC. DNA and RNA were obtained from women with normal ovarian tissues (n=18), ovarian serous cystadenoma tumors (n=11) and EOC (n=16) using Trizol(®). The methylation frequency of the CpG island in the CASPASE-8 promoter was assessed using the methylation-specific PCR assay after DNA bisulfite conversion. Quantitative PCR was performed to quantify the relative levels of CASPASE-8 in each sample. The differences between samples with each group were evaluated using the Mann-Whitney U and Kruskal-Wallis tests as indicated. Hemimethylation of the CASPASE-8 promoter was found in 11.8% of the normal ovary samples, 20% of the cystadenoma tumors and 20% of the metastatic EOC, while methylation of the CASPASE-8 promoter was absent in the EOC primary tissues (P=0.047). An increased CASPASE-8 expression level was observed in all tumor groups. Significant differences were observed in the CASPASE-8 expression levels when compared with all ovarian tumor groups (P=0.0278). Promoter DNA methylation did not associate with expression levels of CASPASE-8, suggesting the presence of other mechanisms in relation to gene expression control in EOC; thus providing a better understanding of this complex disease.

Assuntos

RESUMO

Chronic hepatitis B virus (HBV) infection involves liver damage resulting in continuous cell injury and death. During HBV infection, hepatocytes exhibit changes in death receptor expression and in their susceptibility to death. These changes are observed not only in infected cells but also in bystander cells. Because excess viral surface protein (HBsAg) is secreted in large amounts as soluble particles containing preS proteins, the role of soluble preS1/2 in hepatocyte (HepG2) death modulation is an important issue to be explored. An increase of cell death induced by preS1/2 was observed. Also, cell death was associated with the down-regulation of FLIP and activation of caspase 8, caspase 9, and BID. Additionally, hepatocytes exhibited a sensitization to death mediated by the Fas receptor. These results, may contribute to understanding the role of envelope proteins (preS1/2) in the pathogenesis of HBV infection.

Assuntos