排序方式: 共有17条查询结果,搜索用时 15 毫秒
1.
N. Belén Rumie Vittar María Julia Lamberti María Florencia Pansa Renzo E. Vera M. Exequiel RodriguezI. Sol Cogno Laura N. Milla SanabriaViviana A. Rivarola 《生物化学与生物物理学报:癌评论》2013
As with natural ecosystems, species within the tumor microenvironment are connected by pairwise interactions (e.g. mutualism, predation) leading to a strong interdependence of different populations on each other. In this review we have identified the ecological roles played by each non-neoplastic population (macrophages, endothelial cells, fibroblasts) and other abiotic components (oxygen, extracellular matrix) directly involved with neoplastic development. A way to alter an ecosystem is to affect other species within the environment that are supporting the growth and survival of the species of interest, here the tumor cells; thus, some features of ecological systems could be exploited for cancer therapy. We propose a well-known antitumor therapy called photodynamic therapy (PDT) as a novel modulator of ecological interactions. We refer to this as “ecological photodynamic therapy.” The main goal of this new strategy is the improvement of therapeutic efficiency through the disruption of ecological networks with the aim of destroying the tumor ecosystem. It is therefore necessary to identify those interactions from which tumor cells get benefit and those by which it is impaired, and then design multitargeted combined photodynamic regimes in order to orchestrate non-neoplastic populations against their neoplastic counterpart. Thus, conceiving the tumor as an ecological system opens avenues for novel approaches on treatment strategies. 相似文献
2.
Replication slippage may cause parallel evolution in the secondary structures of mitochondrial transfer RNAs 总被引:9,自引:4,他引:5
Presence of the dihydrouridine (D) stem in the mitochondrial cysteine tRNA
is unusually variable among lepidosaurian reptiles. Phylogenetic and
comparative analyses of cysteine tRNA gene sequences identify eight
parallel losses of the D-stem, resulting in D-arm replacement loops.
Sampling within the monophyletic Acrodonta provides no evidence for
reversal. Slipped-strand mispairing of noncontiguous repeated sequences
during replication or direct replication slippage can explain repeats
observed within cysteine tRNAs that contain a D-arm replacement loop. These
two mechanisms involving replication slippage can account for the loss of
the cysteine tRNA D-stem in several lepidosaurian lineages, and may
represent general mechanisms by which the secondary structures of
mitochondrial tRNAs are altered.
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3.
Croci DO Cogno IS Vittar NB Salvatierra E Trajtenberg F Podhajcer OL Osinaga E Rabinovich GA Rivarola VA 《Journal of cellular biochemistry》2008,105(2):381-390
Survivin is recognized as an attractive target in cancer therapy because of its selective overexpression in the majority of tumors. Upregulated expression of this protein correlates with increased tumor grade, recurrence risk and decreased cancer patients survival. In this study, we assessed the efficacy of two survivin-specific small interfering RNA (siRNA) constructs to inhibit T47D human breast cancer cell growth. After siRNA transfection, T47D cells showed a significant reduction in proliferation and survival exhibiting clear signs of apoptosis. pSil_1 that targeted exon 1 exhibited a stronger inhibitory effect on cell growth, and increased cell apoptosis compared to pSil_30 that targeted exon 4. Cell apoptosis was found to be mediated by translocation of the mitochondrial apoptosis inducing factor (AIF), while no changes were observed in caspase-3 activation and Bid cleavage. Thus, silencing survivin expression using siRNA strategies represents a suitable therapeutic approach to selectively modulate the survival and growth of human breast cancer cells. 相似文献
4.
The complete cDNA sequence and protein reading frame of a developmentally
regulated hemocyanin subunit in the Dungeness crab (Cancer magister) is
presented. The protein sequence is aligned with 18 potentially homologous
hemocyanin-type proteins displaying apparent sequence similarities.
Functional domains are identified, and a comparison of predicted
hydrophilicities, surface probabilities, and regional backbone
flexibilities provides evidence for a remarkable degree of structural
conservation among the proteins surveyed. Parsimony analysis of the protein
sequence alignment identifies four monophyletic groups on the arthropodan
branch of the hemocyanin gene tree: crustacean hemocyanins, insect
hexamerins, chelicerate hemocyanins, and arthropodan prophenoloxidases.
They form a monophyletic group relative to molluscan hemocyanins and
nonarthropodan tyrosinases. Arthropodan prophenoloxidases, although
functionally similar to tyrosinases, appear to belong to the arthropodan
hexamer- type hemolymph proteins as opposed to molluscan hemocyanins and
tyrosinases.
相似文献
5.
Natalia B. Rumie Vittar Josefina Awruch Kashif Azizuddin Viviana Rivarola 《The international journal of biochemistry & cell biology》2010,42(7):1123-1131
A new water-soluble phthalocyanine derivative, 2,3,9,10,16,17,23,24-octakis(3-aminopropyloxy) phthalocyaninato zinc II (PoII) was studied as a photosensitizer for photodynamic therapy (PDT) in MCF-7c3 cells. We report here that PoII and red light induces apoptosis. However, the precise mechanism appears to differ from that induced by PDT with other known phthalocyanines. The present study provides evidence that in the case of PoII, caspases do not participate in the apoptotic response. PoII-PDT-treated cells exhibited chromatin condensation and phosphatidylserine (PS) externalization. In the absence of light activation, PoII had no detectable cytotoxic effect. An early event upon PoII-PDT was photodamage to lysosomes, suggesting that they are the primary sites of action. Moreover, the treatment induces Bid activation, mitochondrial swelling and translocation of apoptosis-inducing factor (AIF) to the nucleus. An atypical proteolysis of poly(ADP-ribose) polymerase (PARP) indicative of calpain-like activation was observed. These data support the notion that an alternative mechanism of caspase-independent apoptosis was found in PoII-photosensitized cells. 相似文献
6.
Charlie T Cheng Enrique M Ostrea Jr Joseph NB Alviedo Felix P Banadera Ronald L Thomas 《Experimental biology and medicine (Maywood, N.J.)》2021,246(4):380
To determine if meconium fatty acid ethyl esters (FAEE) in rat pups is a good biomarker of prenatal exposure and effect to alcohol, three groups of pregnant rats were studied: one control (pair fed) and two treatment groups given 25% alcohol at 2.2 or 5.5 g−1 kg−1 d−1. The pups were delivered on day 20 and, for each dam, were separated into a male and female group. The body, brain, intestines, and placenta of the pups were obtained, weighed, and stored at −20°C. The pups’ intestines (as surrogate of meconium) from each group were pooled, and meconium was analyzed by gas chromatography/mass spectroscopy for FAEE. The meconium showed the following FAEE: ethyl palmitate, ethyl stearate, and ethyl linolenate and were only found in the alcohol-treated group and with high specificity but low sensitivity. Mean body weight of the pups was lower in the treatment groups compared to the control groups. Ethyl palmitate concentration correlated negatively to the pups’ mean body and brain weights. Therefore, ethyl palmitate, stearate, and linolenate, in meconium of rat pups prenatally exposed to alcohol, are useful biomarkers of prenatal alcohol exposure, with ethyl palmitate a good biomarker of adverse effect on the pups’ body and brain weight. 相似文献
7.
Laura Milla Sanabria Matías Exequiel Rodríguez Ingrid Sol Cogno Natalia Belén Rumie Vittar María Florencia PansaMaría Julia Lamberti Viviana Alicia Rivarola 《生物化学与生物物理学报:癌评论》2013
Photodynamic therapy (PDT) is a novel cancer treatment. It involves the activation of a photosensitizer (PS) with light of specific wavelength, which interacts with molecular oxygen to generate singlet oxygen and other reactive oxygen species (ROS) that lead to tumor cell death. When a tumor is treated with PDT, in addition to affect cancer cells, the extracellular matrix and the other cellular components of the microenvironment are altered and finally this had effects on the tumor cells survival. Furthermore, the heterogeneity in the availability of nutrients and oxygen in the different regions of a tridimensional tumor has a strong impact on the sensitivity of cells to PDT. In this review, we summarize how PDT affects indirectly to the tumor cells, by the alterations on the extracellular matrix, the cell adhesion and the effects over the immune response. Also, we describe direct PDT effects on cancer cells, considering the intratumoral role that autophagy mediated by hypoxia-inducible factor 1 (HIF-1) has on the efficiency of the treatment. 相似文献
8.
Hunter NB Moseley Andrew N Lane Alex C Belshoff Richard M Higashi Teresa WM Fan 《BMC biology》2012,10(1):1-2
This article is a response to Wang and Luo. See correspondence article http://www.biomedcentral.com/1741-7007/10/30/ [WEBCITE] and the original research article http://www.biomedcentral.com/1741-7007/9/24 [WEBCITE]. 相似文献
9.
Monoclonal antibodies against chicken type V collagen: production, specificity, and use for immunocytochemical localization in embryonic cornea and other organs 总被引:6,自引:17,他引:6 下载免费PDF全文
TF Linsenmayer JM Fitch TM Schmid Zak NB E Gibney RD Sanderson R Mayne 《The Journal of cell biology》1983,96(1):124-132
Two monoclonal antibodies have been produced against chick type V collagen and shown to be highly specific for separate, conformational dependent determinants within this molecule. When used for immunocytochemical tissue localization, these antibodies show that a major site for the in situ deposition of type V is within the extracellular matrices of many dense connective tissues. In these, however, it is largely in a form unavailable to the antibodies, thus requiring a specific “unmasking” treatment to obtain successful immunocytochemical staining. The specificity of these two IgG antibodies was determined by inhibition ELISA, in which only type V and no other known collagen shows inhibition. In ELISA, mixtures of the two antibodies give an additive binding reaction to the collagen, suggesting that each is against a different antigenic determinant. That both antigenic determinants are conformational dependent, being either in, or closely associated with, the collagen helix is demonstrated by the loss of antibody binding to molecules that have been thermally denatured. The temperature at which this occurs, as assayed by inhibition ELISA, is very similar to that at which the collagen helix melts, as determined by optical rotation. This gives strong additional evidence that the antibodies are directed against the collagen. The antibodies were used for indirect immunofluorescence analyses of cryostat sections of corneas and other organs from 17 to 18-day-old chick embryos. Of all tissues examined only Bowman’s membrane gave a strong staining reaction with cryostat sections of unfixed material. Staining in other areas of the cornea and in other tissues was very light or nonexistent. When, however, sections were pretreated with pepsin dissolved in dilute HAc or, surprisingly, with the dilute HAc itself dramatic new staining by the antibodies was observed in most tissues examined. The staining, which was specific for the anti-type V collagen antibodies, was largely confined to extracellular matrices of dense connective tissues. Experiments using protease inhibitors suggested that the “unmasking” did not involve proteolysis. We do not yet know the mechanism of this unmasking; however, one possibility is that the dilute acid causes swelling or conformational changes in a type-V collagen-containing supramolecular structure. Further studies should allow us to determine whether this is the case. 相似文献
10.
Microsatellite allele frequencies in humans and chimpanzees, with implications for constraints on allele size 总被引:18,自引:6,他引:18
The distributions of allele sizes at eight simple-sequence repeat (SSR) or
microsatellite loci in chimpanzees are found and compared with the
distributions previously obtained from several human populations. At
several loci, the differences in average allele size between chimpanzees
and humans are sufficiently small that there might be a constraint on the
evolution of average allele size. Furthermore, a model that allows for a
bias in the mutation process shows that for some loci a weak bias can
account for the observations. Several alleles at one of the loci (Mfd 59)
were sequenced. Differences between alleles of different lengths were found
to be more complex than previously assumed. An 8-base-pair deletion was
present in the nonvariable region of the chimpanzee locus. This locus
contains a previously unrecognized repeated region, which is imperfect in
humans and perfect in chimpanzees. The apparently greater opportunity for
mutation conferred by the two perfect repeat regions in chimpanzees is
reflected in the higher variance in repeat number at Mfd 59 in chimpanzees
than in humans. These data indicate that interspecific differences in
allele length are not always attributable to simple changes in the number
of repeats.
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