El bloqueo de un solo gen reduce la agresividad de los tumores
El hallazgo es el primer paso para posibles tratamientos de cánceres resistentes a otros fármacos
Un equipo de la Universidad John Hopkins ha descubierto un gen que actúa como un interruptor en los procesos tumorales. En concreto, estudiando células de cáncer de mama humano, han visto que tras su bloqueo el cultivo adquiere el aspecto de un tejido sano. Ello apunta a que un fármaco que actuara en este sentido podría ser una alternativa sobre todo en tumores que sean resistentes a los medicamentos hasta ahora en uso. El artículo lo publica PLOS.
El gen que ha sido objeto del estudio pertenece a una familia de amplias propiedades, los HMG (iniciales High Movility Group, grupo de elevada movilidad). Ya en el nombre indica que tiene una relación con el crecimiento celular, cuyo descontrol es la causa de los cánceres.
"Este regulador maestro está normalmente desactivado en las células adultas", ha dicho Linda Resar, investigadora de la Johns Hopkins. "En cambio, está muy activa en el desarrollo embrionario y en las fases agresivas de todos los tumores que se han estudiado". "Nuestro trabajo muestra por primera vez que desactivando este gen en células de una forma agresiva de cáncer cambia extraordinariamente su apariencia y su comportamiento", ha añadido.
El trabajo, realizado en cultivos celulares, puede ser de gran interés en casos para los que no hay tratamiento. Por ejemplo, en el estudio se utilizaron las células llamadas triple negativas, porque no tienen ninguno de los genes o receptores que caracterizan las formas más habituales de cáncer de mama. Esta falta de señales, como el gen HER2, hacen que sean más difíciles de abordar. Después de alterar las células para inhibir el HMG1 se implantaron en ratones, y se vio que no se propagaban. En cambio, los cultivos no manipulados causaban metástasis.Trabajos anteriores de Resar habían ya intervenido sobre el gen HMG1 pero aplicados a la reprogramación de células madre. Esto es lógico visto su papel en la proliferación y especialización celular. De paso, el estudio pone de manifiesto, otra vez, la relación entre células madre y cáncer. Cuando las primeras se activan de manera inadecuada, aparecen los segundos.
El siguiente paso, ha dicho Resar, es obvio: intentar desarrollar un tratamiento basado en este principio. Algo que, si funciona, puede llevar hasta una década.
Comentario: Nos encontramos ante un artículo vinculado al ámbito de la ingeniería genética, de carácter prácticamente actual, cuya temática es la reducción de posibilidades de generar cáncer mediante la modificación. Aunque dicha ingeniería se considera en la actualidad una ciencia relativamente ''en pañales'' no muestra otra cosa que oportunidades para el desarrollo de la biotecnología y la mejora de nuestra calidad de vida. En este caso las expectativas son muy ansiadas, pues todavía nos queda bastante por descubrir el enigma genético/ambiental preciso que determina la aparición de un cáncer, una enfermedad no infecciosa que, por desgracia, actualmente afecta sobre la sociedad duramente, situándose en 2008, según la OMS el número de muertos en torno a los 7,6 millones de defunciones. Así, aunque no se pueda decir que se trata más que de un comienzo, el suceso noticiario es uno de los muy numerosos logros científicos que se han dado hasta el presente.
Obtenido un virus de gripe con alta mortalidad y capacidad de transmisión
El experimento, en cobayas, combinó genes de la gripe A de 2009 con la aviar de 2003.
Pretende adelantarse al riesgo de recombinación en la naturaleza.
Un laboratorio de Harbin, al noreste de China, guarda en sus instalaciones el patógeno perfecto: combina la elevada letalidad del virus de la gripe aviar de 2003 (el H5N1) con la facilidad de transmisión –al menos entre cobayas- del de la que se denominó nueva gripe o gripe A de 2009, un H1N1. El trabajo que da cuenta del experimento lo ha publicado Science, y ha sido rápidamente replicado por Nature.
En concreto, el estudio de la investigadora Chen Hualan ha tomado el H5N1 como base, y le ha ido introduciendo genes del H1N1. Ella lo ha hecho en laboratorio, pero la idea es que es algo que puede suceder en la naturaleza si ambos virus coinciden en un mismo huésped (una persona o un cerdo, por ejemplo). Y eso, destacan los autores, no es tan raro. Aunque parezca olvidado, el H5N1 no ha desaparecido. Ha provocado un auténtico desastre en las granjas del sureste asiático con millones de aves muertas y otras tantas sacrificadas, y llevaba, según el último recuento de la Organización Mundial de la Salud del 26 de abril, 374 fallecidos desde 2003 (13 de ellos este año), con una letalidad (proporción de muertos por infectados) del 59,6%. Por otro lado, el H1N1 ya demostró su capacidad de propagación en 2009, cuando de un foco en México se expandió a todo el planeta en tres meses. Tanto, que aún sigue circulando y, por ejemplo, forma parte de los virus contra los que se fabrican vacunas de la gripe cada año desde entonces, incluida la prevista para el invierno de 2013.
Lo que ha hecho Chen ha sido intercambiar genes enteros del H5N1 por los del H1N1 y creó hasta 127 virus recombinantes. Este proceso es habitual en la naturaleza, y es una de las maneras en que los virus se adaptan y modifican (la otra es por medio de mutaciones). Los virus, como las bacterias, son organismo relativamente sencillos. Los de la gripe solo tienen ocho genes, y son bastante promiscuos: cuando coinciden con un congénere, se interrelacionan. En el mundo de los virus eso quiere decir que comparten material genético.
La investigadora China luego utilizó sus ejemplares para infectar cobayas, y midió con qué facilidad el virus se transmitía de los roedores afectados a los sanos. Así pudo delimitar que bastaba que el H5N1 original intercambiara dos genes concretos con el H1N1 para convertirse en fácilmente transmisible. Y no hacía falta que el intercambio fuera de ambos a la vez; bastaba con que lo hiciera con uno u otro. Esto parece una mala señal: es la recombinación (el nombre que se da a este trasiego de genes) más sencilla.
Lo que sí que ha sucedido, como hace un año, es que ha habido críticas a que el trabajo se publique. El miedo que existe es a que algún grupo terrorista pueda intentar fabricar un arma bioquímica siguiendo los trabajos de Chen (o de otros colegas). Aunque eso no está tan claro. Las cobayas tienen una diferencia importante con respecto a los humanos: sus pulmones tienen receptores para el virus de la gripe aviar, mientras que las personas los tienen solo para virus adaptados a mamíferos. Esto explica la extrañeza cada vez que hay un salto entre especies como el del H5N1 o el reciente del H7N9 y, a la vez, por qué parece que la expansión de ambos patógenos está contenida, ya que la transmisión entre humanos no es nada fácil. Esta diferencia es señalada por algunos especialistas. Aunque la capacidad de transmitirse pueda conseguirse con un cambio de genes, como se ha visto en el estudio, la infectividad real en humanos depende de todo el conjunto, y eso no se ha podido demostrar.El trabajo ha sido publicado sin pegas aparentes en las revistas científicas de más renombre, lo que choca con lo que sucedió hace un año cuando otros investigadores hicieron algo parecido: establecer qué tres mutaciones bastaban en el H5N1 para que se convirtiera en fácilmente transmisible entre hurones (que es otro de los animales que se usan como modelo ya que lo que sucede en estos animales, cuando a gripe se refiere, suele ser de aplicación en humanos). La propia Chen ha declarado que le hubiera gustado hacer su ensayo también en hurones, pero que no pudo, entre otras cosas porque ahora está volcada en el H7N9.
La investigadora china afirma que su objetivo es adelantarse a un riesgo posible. El H5N1 sigue activo en Camboya, Vietnam, China y Egipto, y todos estos países son territorios que también ocupa el H1N1. Tener un modelo para investigar antes de que haya ejemplares en la naturaleza puede ser útil si el patógeno no escapa de las instalaciones. China ha dado pasos de gigante para ganar calidad y confianza por sus trabajos (por ejemplo, lidera claramente la investigación en el H7N9, algo que no sucedió con el H5N1 o el SARS). Pero eso no evita recelos de algunos. Por ejemplo, de Simon Wain-Hobson, virólogo del Instituto Pasteur de París, quien ha declarado a Science que el trabajo -de mucha calidad,
eso sí- “es muy peligroso”.
Comentario: El presente artículo noticiario nos lleva a situarnos dentro del ámbito de la ingeniería genética, en la modificación genética de un virus, creándose otro ''a la carta'' caracterizado por la alta mortalidad que generaría en el ser humano. Ello es debido a que el ser recombinante obtenido posee tanto genes de la virulenta gripe aviar de 2003 como de la transmisible gripe A que azotó al ser humano en 2009. El objetivo, según indica la noticia es adelantarse al posible hecho de que las múltiples mutaciones virales provocaran dicha unión de genes de forma natural. Con la obtención del virus se podría proceder a la búsqueda de la vacuna, y suponiendo una ganancia de tiempo con respecto a la enfermedad, pues quizás si tiene lugar la formación de un virus semejante no habría más que producir en mayor cantidad la sustancia que ya tenemos como vacuna. Otro aspecto a resaltar es el mal uso que se puede dar del virus entre potencias enemigas en caso de guerra, perdiéndose los valores que defiende la ética de la ciencia, por lo que en cierta instancia, podría suponer algo negativo.
http://sociedad.elpais.com/sociedad/2013/05/03/actualidad/1367584080_767702.html
Comentario: Nos encontramos frente a un artículo perteneciente al ámbito de la ingeniería genética, aplicado por completo a la biotecnología. El colesterol supone en exceso un gran problema debido a que produce un aumento de la rigidez de las paredes,constituidas por membranas plasmáticas celulares, de los vasos sanguíneos. Este suceso puede desembocar en la arteriosclerosis, enfermedad bastante preocupante debido a que si las padeces arteriales pierden flexibilidad puede afectar a la cantidad de bombeo sanguíneo o, en casos más graves, producir la rotura de estos. Por tanto, es para reconocerlo este hecho. Sin embargo, señalar en contra que debemos poseer colesterol en nuestro cuerpo, en cantidades razonables, por tanto, lo mejor es optar por una idea mesurada de la ingesta de estos alimentos a personas que los necesiten, siempre y cuando se haya seguido un proceso de análisis de resultados en un número progresivo de voluntarios para determinar su no afección maligna al ser humano.
El articulo pertenece a la revista ''Muy Interesante''.
A Dream of Trees Aglow at Night
Hoping to give new meaning to the term “natural light,” a small group of biotechnology hobbyists and entrepreneurs has started a project to develop plants that glow, potentially leading the way for trees that can replace electric streetlamps and potted flowers luminous enough to read by.
Rather than being the work of a corporation or an academic laboratory, it will be done by a small group of hobbyist scientists in one of the growing number of communal laboratories springing up around the nation as biotechnology becomes cheap enough to give rise to a do-it-yourself movement.
The project is also being financed in a D.I.Y. sort of way: It has attracted more than $250,000 in pledges from about 4,500 donors in about two weeks on the Web site Kickstarter.
The effort is not the first of its kind. A university group created a glowing tobacco plant a few years ago by implanting genes from a marine bacterium that emits light. But the light was so dim that it could be perceived only if one observed the plant for at least five minutes in a dark room.
The new project’s goals, at least initially, are similarly modest. “We hope to have a plant which you can visibly see in the dark (like glow-in-the-dark paint), but don’t expect to replace your light bulbs with version 1.0,” the project’s Kickstarter page says.
But part of the goal is more controversial: to publicize do-it-yourself synthetic biology and to “inspire others to create new living things.” As promising as that might seem to some, critics are alarmed at the idea of tinkerers creating living things in their garages. They fear that malicious organisms may be created, either intentionally or by accident.
Two environmental organizations, Friends of the Earth and the ETC Group, have written to Kickstarter and to the Agriculture Department, which regulates genetically modified crops, in an effort to shut down the glowing plant effort.
The project “will likely result in widespread, random and uncontrolled release of bioengineered seeds and plants produced through the controversial and risky techniques of synthetic biology,” the two groups said in their letter demanding that Kickstarter remove the project from its Web site.
They note that the project has pledged to deliver seeds to many of its 4,000 contributors, making it perhaps the “first-ever intentional environmental release of an avowedly ‘synthetic biology’ organism anywhere in the world.” Kickstarter told the critics to take up their concerns with the project’s organizers. The Agriculture Department has not yet replied.
Antony Evans, the manager of the glowing plant project, said in an interview that the activity would be safe.
“What we are doing is very identical to what has been done in research laboratories and big institutions for 20 years,” he said. Still, he added, “We are very cognizant of the precedent we are setting” with the do-it-yourself project and that some of the money raised would be used to explore public policy issues.
Synthetic biology is a nebulous term and it is difficult to say how, if at all, it differs from genetic engineering.
In its simplest form, genetic engineering involves snipping a gene out of one organism and pasting it into the DNA of another. Synthetic biology typically involves synthesizing the DNA to be inserted, providing the flexibility to go beyond the genes found in nature.
The glowing plant project is the brainchild of Mr. Evans, a technology entrepreneur in San Francisco, and Omri Amirav-Drory, a biochemist. They met at Singularity University, a program that introduces entrepreneurs to futuristic technology.
Dr. Amirav-Drory runs a company called Genome Compiler, which makes a program that can be used to design DNA sequences. When the sequence is done, it is transmitted to a mail-order foundry that synthesizes the DNA.
Kyle Taylor, who received his doctorate in molecular and cell biology at Stanford last year, will be in charge of putting the synthetic DNA into the plant. The research will be done, at least initially, at BioCurious, a communal laboratory in Silicon Valley that describes itself as a “hackerspace for biotech.”
The first plant the group is modifying is Arabidopsis thaliana, part of the mustard family and the laboratory rat of the plant world. The organizers hope to move next to a glowing rose.
Scientists have long made glowing creatures for research purposes, including one or more monkeys, cats, pigs, dogs and worms. Glowing zebra fish have been sold in some aquarium shops for years.
These creatures typically have the gene for a green fluorescent protein, derived from a jellyfish, spliced into their DNA. But they glow only when ultraviolet light is shined on them.
Others going back to the 1980s have transplanted the gene for luciferase, an enzyme used by fireflies, into plants. But luciferase will not work without another chemical called luciferin. So the plants did not glow unless luciferin was constantly fed to them. In 2010, researchers at Stony Brook University reported in the journal Plos One that they had created a tobacco plant that glowed entirely on its own, however dimly. They spliced into the plant all six genes from a marine bacterium necessary to produce both luciferase and luciferin.
Alexander Krichevsky, who led that research, has started a company, BioGlow, to commercialize glowing plants, starting with ornamental ones, since it is still impractical to replace light bulbs.
“Wouldn’t you like your beautiful flowers to glow in the dark?” he said, invoking the glowing foliage in the movie “Avatar.”
Dr. Krichevsky declined to provide more about the products, timetables or the investors backing his company, which is based in St. Louis.
Whether it will ever be possible to replace light bulbs remains to be seen and depends to some extent on how much of the plant’s energy can be devoted to light production while still allowing the plant to grow. Mr. Evans said his group calculated, albeit with many assumptions, that a tree that covers a ground area of 10 meters (nearly 33 feet) by 10 meters might be able to cast as much light as a street lamp.
While the Agriculture Department regulates genetically modified plants, it does so under a law covering plant pests.
BioGlow has already obtained a letter from the department saying that it will not need approval to release its glowing plants because they are not plant pests, and are not made using plant pests. The hobbyist project hopes to get the same exemption.
Todd Kuiken, senior research associate at the Woodrow Wilson Center in Washington, who has been studying the governance of both synthetic biology and the do-it-yourself movement, said the glowing plant project was an ideal test case.
“It exposes the gaps and holes in the regulatory structure, while it is, I would argue, a safe product in the grand scheme of things,” Dr. Kuiken said. “A serious look needs to be taken at the regulatory system to see if it can handle the questions synthetic biology is going to raise.”
Commentary: Hitherto i've resalted uses of genetic engineering applicated to medicine and food world, however, as we can see in this article published on May 7, 2013, genetic engineering can also be used in order to conserve the world, in other words, to replace pollutants or in need of energy instruments of our world, like car emissions, or, like in this case, the illumination of cities and people-dwelled areas. The answer that this hobbyists scientist propose is to change some plants genome, resulting a new species of plants which that glow at night. Of course, it's done by a sophisticated form of genetix engineering(sintetic biology). Personally it's a brilliant idea, but like i hope they have thought, another character that they have to change is the agressiveness of the new recombinant plant, and the resistance to hard conditions, because the primitive perhaps was selected from EEUU, that maybe cannot develope his life in another climates. So if the experiment become and exit, these are another characters that this scientist must change.
Fish’s DNA May Explain How Fins Turned to Feet
In the hope of reconstructing a pivotal step in evolution — the colonization of land by fish that learned to walk and breathe air — researchers have decoded the genome of the coelacanth, a prehistoric-looking fish whose form closely resembles those seen in the fossils of 400 million years ago.
Often called a living fossil, the coelacanth (pronounced SEE-luh-canth) was long believed to have fallen extinct 70 million years ago, until a specimen was recognized in a fish market in South Africa in 1938. The coelacanth has fleshy, lobed fins that look somewhat like limbs, as does the lungfish, an air-breathing freshwater fish. The coelacanth and the lungfish have long been battling for the honor of which is closer to the ancestral fish that first used fins to walk on land and give rise to the tetrapods, meaning all the original vertebrates and their descendants, from reptiles and birds to mammals.
The decoding of the coelacanth genome, reported online Wednesday in the journal Nature, is a victory for the lungfish as the closer relative to the first tetrapod. But the coelacanth may have the last laugh because its genome — which, at 2.8 billion units of DNA, is about the same size as a human genome — is decodable, whereas the lungfish genome, a remarkable 100 billion DNA units in length, cannot be cracked with present methods. The coelacanth genome is therefore more likely to shed light on the central evolutionary question of what genetic alterations were needed to change a lobe-finned fish into the first land-dwelling tetrapod.
The idea of decoding the coelacanth genome began six years ago when Chris Amemiya, a biologist at the University of Washington in Seattle, acquired some samples of coelacanth tissue. He asked the Broad Institute of Harvard and M.I.T., a biological research institute in Cambridge, Mass., to decode the DNA and invited experts in evolutionary and developmental biology to help interpret the results.
Dr. Amemiya’s team has sifted through the coelacanth’s genome for genes that might have helped its cousin species, the ancestor to the first tetrapod, invade dry land some 400 million years ago. They have found one gene that is related to those that, in animal species, build the placenta. Coelacanths have no placenta, but they produce extremely large eggs, with a good blood supply, that hatch inside the mother’s body. This gene could have been developed by land animals into a way of constructing the placenta.
Another helpful preadaptation is a snippet of DNA that enhances the activity of the genes that drive the formation of limbs in the embryo. The Amemiya team focused on the enhancer DNA sequence because it occurred in the coelacanth and animals but not in ordinary fish. They then inserted the coelacanth enhancer DNA into mice.
“It lit up right away and made an almost normal limb,” said Neil Shubin, meaning that the coelacanth gene enhancer successfully encouraged the mouse genes to make a limb. Dr. Shubin, a member of the team, is a paleontologist at the University of Chicago.
Present-day coelacanths are ferocious predators that live in a twilight zone about 500 feet deep where light barely penetrates. They lurk in caves during the day and emerge at night to attack surface fish as they descend and deep-sea fish as they rise to the surface. They have no evident need of fins that might help them walk on land.
“This is probably an unusual habitat for this lineage,” said Axel Meyer, an evolutionary biologist at the University of Konstanz in Germany and a member of the team. “Other coelacanths lived in more shallow, estuarylike environments 400 million years ago, and you can envisage them using the fins more like walking legs.”
The Amemiya team reports evidence that the coelacanth’s genes have been evolving more slowly than those of mammals, possibly because of “a static habitat and lack of predators.” But its environment must have changed quite considerably over the last 400 million years, Dr. Meyer said. Its principal habitat at present is the caves beneath the Comoro Islands in the Indian Ocean, but since these are extinct volcanoes a mere 5 million to 10 million years old, they must be a quite recent home for the coelacanth.
The Amemiya team does not possess a full coelacanth — these are endangered species — and decoded the genome from tissues obtained from Rosemary Dorrington of Rhodes University in South Africa. Dr. Dorrington supplied DNA kits to the Comoro Islands fishermen who occasionally snag coelacanths by accident. When a coelacanth was captured in 2003, they preserved blood and tissues, which were given to Dr. Dorrington and kept frozen, Dr. Amemiya said.
The specimen was preserved in Moroni, the capital of the Comoro Islands, but Dr. Amemiya has been unable to find out where it is now because of the constant state of civil war in the islands, he said.
Can he be certain, then, that the tissue came from a coelacanth? “Oh, no question,” Dr. Amemiya said. “We have DNA from several other coelacanths, from Africa and Indonesia, which is very similar to this one.” The one caught in 2003 was identified as a coelacanth by Said Ahamada, a South African expert, Dr. Amemiya said.
Because the original specimen is not available and the DNA sequencing is incomplete, the Amemiya team does not know its sex.
Lobe-finned fish like the coelacanth and lungfish are known to zoologists as sarcopterygians, meaning fleshy fins. Tetrapods, including people, are descended from this group, and the coelacanth is more closely related to people than to other fish. “Evolutionarily speaking, we are sarcopterygian fish,” Dr. Meyer said.
Commentary: refering to the article, which was published on April 17, 2013, we can say that another way or using genetic engineering is in history of evolution's world. In this case, by examining, and desciphering the genome of coelancath, an ancient fish that humanity thought for a long time that it was extincted, but appeared in a market of South Africa in 1938, scientists want to discover the link between the life in water, where took place the firts way of life on earth, and life in solid ground. A characteristic of the coelancath is to have fleshy and lobed fins, that look like limbs. In my oppinion it very interesting to know that we are here also as a result of an evolution procces, and it won't be clear to everyone untill the reveal the links between all living species. A lot of people still think that we were done 'in the image and likeness of God', which is a bit worrying if humanity wants to progress. In this line, a quote from Nietzsche says: 'is human only a God failure, or is God human failure?'
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