RESUMO
Photodynamic therapy is an alternative treatment for several pathologies, including cancer. This therapy uses a photosensitizer capable of producing reactive oxygen species through irradiation, promoting cellular death. A limitation of photosensitizers is their low solubility in aqueous media. Hence, developing a suitable carrier for photosensitizers for specific applications is a challenge. Cervical cancer is one of the most common cancers in women, and photodynamic therapy could be an attractive alternative therapeutic approach. In this work, we synthesized films composed of chitosan, polyvinylpyrrolidone, and liposomes containing Zn-phthalocyanine. Photophysical characterization of ZnPc incorporated into films was determined by UV-vis and fluorescence. Film properties such as swelling, mechanical properties, and water vapor permeability were performed. Finally, in vitro, photodynamic evaluation of these films was performed on HeLa cells. The results indicate that incorporating Zn-Pc-liposomes into films decreases cell viability by >95 %.
Assuntos
Quitosana , Compostos Organometálicos , Fotoquimioterapia , Feminino , Humanos , Lipossomos , Fármacos Fotossensibilizantes/farmacologia , Células HeLa , Fotoquimioterapia/métodos , Compostos de ZincoRESUMO
Gliomas are solid tumors of the central nervous system (CNS) that originated from different glial cells. The World Health Organization (WHO) classifies these tumors into four groups (I-IV) with increasing malignancy. Glioblastoma (GBM) is the most common and aggressive type of brain tumor classified as grade IV. GBMs are resistant to conventional therapies with poor prognosis after diagnosis even when the Stupp protocol that combines surgery and radiochemotherapy is applied. Nowadays, few novel therapeutic strategies have been used to improve GBM treatment, looking for higher efficiency and lower side effects, but with relatively modest results. The circadian timing system temporally organizes the physiology and behavior of most organisms and daily regulates several cellular processes in organs, tissues, and even in individual cells, including tumor cells. The potentiality of the function of the circadian clock on cancer cells modulation as a new target for novel treatments with a chronobiological basis offers a different challenge that needs to be considered in further detail. The present review will discuss state of the art regarding GBM biology, the role of the circadian clock in tumor progression, and new chrono-chemotherapeutic strategies applied for GBM treatment.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Ritmo Circadiano/efeitos dos fármacos , Desenvolvimento de Medicamentos , Glioblastoma/tratamento farmacológico , Preparações Farmacêuticas/administração & dosagem , Animais , HumanosRESUMO
Coffee consumption is believed to have chemopreventive and chemotherapeutic effects and to contribute to preventing the development and progression of cancer. However, there is still controversy around these claims. As indicated in our previous works, diet can influence the risk of breast cancer. Intake of coffee is hypothesized to reduce this risk, but current scientific evidence is not conclusive. This work is aimed at studying the effects of Robusta coffee bean extract on cell viability, proliferation, and apoptosis of different human cancers, especially breast cancer cell lines. To this end, cell viability was evaluated by Alamar Blue in 2D and 3D models, the cell cycle by PI, apoptosis by annexin V, mitochondrial morphology, and functionality by mitoTracker, and colony formation capacity by the clonogenic assay. Green and dark coffee extract significantly reduced viability in human breast, colorectal, brain, and bone cancer cells. Coffee anticancer activity was clearly evidenced in MDA-MB-231 (ER-) and MCF-7 (ER+) breast cancer cells but not in the normal breast cell line. In addition, coffee extract induces an increase S phase and a decrease G2/M population in breast cancer cells, affected the mitochondrial morphology, and triggered apoptosis. MDA-MB-231 breast cancer cells lost their clonogenic capacity after treatment. The antitumor activity was demonstrated in both 2D and 3D culture cell models.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Coffea/química , Café/química , Extratos Vegetais/uso terapêutico , Apoptose , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Feminino , HumanosRESUMO
Tumors of the nervous system including glioblastoma multiforme (GBM) are the most frequent and aggressive form of brain tumors; however, little is known about the impact of the circadian timing system on the formation, growth, and treatment of these tumors. We investigated day/night differences in tumor growth after injection of A530 glioma cells isolated from malignant peripheral nerve sheath tumor (MPNSTs) of NPcis (Trp53+/- ; Nf1+/- ) mice. Synchronized A530 cell cultures expressing typical glial markers were injected at the beginning of the day or night into the sciatic nerve zone of C57BL/6 mice subject to a 12:12 hours light/dark (LD) cycle or after being released to constant darkness (DD). Tumors generated in animals injected early at night in the LD cycle or in DD showed higher growth rates than in animals injected diurnally. No differences were found when animals were injected at the same time with cultures synchronized 12 hours apart. Similar experiments performed with B16 melanoma cells showed higher tumor growth rates in animals injected at the beginning of the night compared to those injected in the daytime. A higher tumor growth rate than that in controls was observed when mice were injected with knocked-down clock gene Bmal1 cells. Finally, when we compared day/night administration of different doses of the proteasome inhibitor Bortezomib (0.5-1.5 mg/kg) in tumor-bearing animals, we found that low-dose chemotherapy displayed higher efficacy when administered at night. Results suggest the existence of a precise temporal control of tumor growth and of drug efficacy in which the host state and susceptibility are critical.
Assuntos
Neoplasias Encefálicas/patologia , Ritmo Circadiano , Glioblastoma/patologia , Fotoperíodo , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Fatores de Transcrição ARNTL/genética , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Bortezomib/administração & dosagem , Bortezomib/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Esquema de Medicação , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Camundongos , Camundongos Endogâmicos C57BL , Neurofibromina 1/genética , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genética , Ensaios Antitumorais Modelo de Xenoenxerto/normasRESUMO
Glioblastoma is the most severe form of brain cancer. Despite multimodal therapy combining surgery, radiotherapy and chemotherapy, prognosis of patients is dismal. It has been observed that the surgical resection guided by photosensitizer fluorescence followed by photodynamic therapy (PDT) prolongs the average survival in patients with glioblastoma. The main problem with all oncological treatments, including PDT, is the presence of resistant cells. The objective of this study was to isolate and perform an initial characterization of human glioblastoma cells resistant to PDT employing methyl-5-aminolevulinic acid. We obtained resistant cells from the T98 G cell line. Resistant populations accumulated less photosensitizer, formed spheroids of higher number of cells, had higher tumorigenic capacity, and expressed higher mRNA levels of fibroblastic growth factor receptor (FGFR), epidermal growth factor receptor (EGFR) and ß-platelet-derived growth factor receptor (ßPDGFR) than parental cells. The studies of glioblastoma resistance to PDT would help to better understand the causes of tumor recurrence after PDT and to develop new therapeutic proposals in this field of oncology.
Assuntos
Glioblastoma , Fotoquimioterapia , Ácido Aminolevulínico/farmacologia , Ácido Aminolevulínico/uso terapêutico , Linhagem Celular Tumoral , Glioblastoma/tratamento farmacológico , Humanos , Recidiva Local de Neoplasia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêuticoRESUMO
Glioblastoma multiforme is the most aggressive type of tumor of the CNS with an overall survival rate of approximately one year. Since this rate has not changed significantly over the last 20 years, the development of new therapeutic strategies for the treatment of these tumors is peremptory. The over-expression of the proto-oncogene c-Fos has been observed in several CNS tumors including glioblastoma multiforme and is usually associated with a poor prognosis. Besides its genomic activity as an AP-1 transcription factor, this protein can also activate phospholipid synthesis by a direct interaction with key enzymes of their metabolic pathways. Given that the amino-terminal portion of c-Fos (c-Fos-NA: amino acids 1-138) associates to but does not activate phospholipid synthesizing enzymes, we evaluated if c-Fos-NA or some shorter derivatives are capable of acting as dominant-negative peptides of the activating capacity of c-Fos. The over-expression or the exogenous administration of c-Fos-NA to cultured T98G cells hampers the interaction between c-Fos and PI4K2A, an enzyme activated by c-Fos. Moreover, it was observed a decrease in tumor cell proliferation rates in vitro and a reduction in tumor growth in vivo when a U87-MG-generated xenograft on nude mice is intratumorally treated with recombinant c-Fos-NA. Importantly, a smaller peptide of 92 amino acids derived from c-Fos-NA retains the capacity to interfere with tumor proliferation in vitro and in vivo. Taken together, these results support the use of the N-terminal portion of c-Fos, or shorter derivatives as a novel therapeutic strategy for the treatment of glioblastoma multiforme.
Assuntos
Proliferação de Células , Glioblastoma/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Fosfolipídeos/biossíntese , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Linhagem Celular Tumoral , Ativação Enzimática , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Antígenos de Histocompatibilidade Menor/genética , Fosfolipídeos/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-fos/genética , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismoRESUMO
Glioblastoma multiforme is considered to be one of the most aggressive types of tumors of the central nervous system, with a poor prognosis and short survival periods of ~ one year. The current protocol for glioblastoma treatment includes the surgical excision of the primary tumor followed by radio and chemotherapy. Photodynamic therapy (PDT) is considered a promising strategy for the treatment of several types of tumors. Phthalocyanines (Pcs) are good photosensitizers (PSs) for PDT because they induce cell death in several cellular models. ZnPc (Zn(II)phthalocyanine) is a well-known Pc, extensively tested in different cells and tumor models, but its evaluation on a glioblastoma model has been poorly studied. Herein, we compare the capacity of ZnPc and one of its derivatives, Zn(II)tetraminephthalocyanine (TAZnPc), to photoinactivate glioblastoma cells (T98G, MO59, LN229 and U87-MG) in culture. We measured the cellular uptake, the toxicity in the dark and the subcellular localization of the different Pcs, as well as the clonogenic capacity of surviving cells after PDT. The mechanism of cell death induced after PDT was determined by measuring caspase 3 activation, DNA fragmentation, phosphatidylserine externalization, mitochondrial morphological changes and loss of mitochondrial membrane potential as well as lysosomal membrane integrity. Overall, ZnPc and TAZnPc present good properties to be used as PSs with photoinactivation capacity on glioblastoma cells.
Assuntos
Glioblastoma/tratamento farmacológico , Indóis/toxicidade , Compostos Organometálicos/toxicidade , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/toxicidade , Caspase 3/metabolismo , Linhagem Celular Tumoral , Fragmentação do DNA , Humanos , Indóis/química , Indóis/farmacologia , Isoindóis , Lisossomos/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Compostos de ZincoRESUMO
Intestinal and free-living protozoa, such as Giardia lamblia, express a dense coat of variant-specific surface proteins (VSPs) on trophozoites that protects the parasite inside the host's intestine. Here we show that VSPs not only are resistant to proteolytic digestion and extreme pH and temperatures but also stimulate host innate immune responses in a TLR-4 dependent manner. We show that these properties can be exploited to both protect and adjuvant vaccine antigens for oral administration. Chimeric Virus-like Particles (VLPs) decorated with VSPs and expressing model surface antigens, such as influenza virus hemagglutinin (HA) and neuraminidase (NA), are protected from degradation and activate antigen presenting cells in vitro. Orally administered VSP-pseudotyped VLPs, but not plain VLPs, generate robust immune responses that protect mice from influenza infection and HA-expressing tumors. This versatile vaccine platform has the attributes to meet the ultimate challenge of generating safe, stable and efficient oral vaccines.
Assuntos
Giardia lamblia/química , Vacinas contra Influenza/imunologia , Proteínas de Membrana/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Proteínas de Protozoários/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Adjuvantes Imunológicos , Administração Oral , Animais , Apresentação de Antígeno/efeitos dos fármacos , Bioengenharia/métodos , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/virologia , Feminino , Expressão Gênica , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Imunidade Inata/efeitos dos fármacos , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Masculino , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Neuraminidase/genética , Neuraminidase/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/virologia , Estabilidade Proteica , Proteínas de Protozoários/genética , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologia , Trofozoítos/química , Vacinação , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/genéticaRESUMO
During evolution, parasitic microorganisms have faced the challenges of adapting to different environments to colonize a variety of hosts. Giardia lamblia, a common cause of intestinal disease, has developed fascinating strategies to adapt both outside and inside its host's intestine, such as trophozoite differentiation into cyst and the switching of its major surface antigens. How gene expression is regulated during these adaptive processes remains undefined. Giardia lacks some typical eukaryotic features, like canonical transcription factors, linker histone H1, and complex promoter regions; suggesting that post-transcriptional and translational control of gene expression is essential for parasite survival. However, epigenetic factors may also play critical roles at the transcriptional level. Here, we describe the most common post-translational histone modifications; characterize enzymes involved in these reactions, and analyze their association with the Giardia's differentiation processes. We present evidence that NAD+-dependent and NAD+-independent histone deacetylases regulate encystation; however, a unique NAD+-independent histone deacetylase modulate antigenic switching. The rates of acetylation of H4K8 and H4K16 are critical for encystation, whereas a decrease in acetylation of H4K8 and methylation of H3K9 occur preferentially during antigenic variation. These results show the complexity of the mechanisms regulating gene expression in this minimalistic protozoan parasite.
Assuntos
Variação Antigênica , Giardia lamblia/imunologia , Giardia lamblia/metabolismo , Histonas/metabolismo , Acetilação/efeitos dos fármacos , Variação Antigênica/efeitos dos fármacos , Eucromatina/metabolismo , Giardia lamblia/citologia , Giardia lamblia/genética , Heterocromatina/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Histonas/química , Lisina/metabolismo , NAD/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacosRESUMO
c-Fos is a proto-oncogene involved in diverse cellular functions. Its deregulation has been associated to abnormal development and oncogenic progression. c-fos-/- mice are viable but present a reduction in their body weight and brain size. We examined the importance of c-Fos during neocortex development at 13.5, 14.5 and 16.5 days of gestation. At E14.5, neocortex thickness, apoptosis, mitosis and expression of markers along the different stages of Neural Stem Progenitor Cells (NSPCs) differentiation in c-fos-/- and wild-type mice were analyzed. A ~15% reduction in the neocortex thickness of c-fos-/- embryos was observed which correlates with a decrease in the number of differentiated cells and an increase in apoptosis at the ventricular zone. No difference in mitosis rate was observed, although the mitotic angle was predominantly vertical in c-fos-/- embryos, suggesting a reduced trend of NSPCs to differentiate. At E13.5, changes in differentiation markers start to be apparent and are still clearly observed at E16.5. A tendency of more AP-1/DNA complexes present in nuclear extracts of cerebral cortex from c-fos-/- embryos with no differences in the lipid synthesis activity was found. These results suggest that c-Fos is involved in the normal development of NSPCs by means of its AP-1 activity.