“Latest Stem Cells News”

Research has indicated that certain sarcomas come from the mesenchymal stem cells. However, expression of neural stem cells has been noted in others. Identifying and isolating mesenchymal stem cells and neural stem cells relies on finding specific proteins expressed by both types.

In this study, eight different markers representing proteins associated with these two types of stem cells were applied to the 81 tumors. Through cluster analysis, the researchers organized the data into groups showing similar patterns. Two major subgroups of pediatric sarcomas emerged

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The key to eradicating tumors and preventing relapses and metastasis is buried within the tumor itself. The tumor cells themselves contain a sort of needle in the haystack. Just 1% of the total volume of the tumor is responsible for reproduction, and a targeted surgery or drugs could be sufficient enough to “deactivate” the tumor and avoid any possibility of a reoccurrence. This type of treatment could possibly change the therapeutic approach to malignant tumors according to an Italian study at the Superior Health Institute (ISS) by Professor Ruggero De Maria, the Director of the Hematology, Oncology, and Molecular Medicine Department of the ISS in collaboration with professor Vito D’Andrea of the ‘Sapienza’ University in Rome.

Stem cells could be responsible for some forms of aggressive thyroid tumors (ATC, anaplastic thyroid carcinoma). The discovery was made by a young group of biotechnologists, biologists, and doctors from the Endocrinology department of the General Hospital of the University of Palermo. In the study, published in Plos One, the researchers described a subset of tumor stem cells that were able to proliferate continuously and may be responsible for uncontrolled tumor growth. These cells are resistant to chemotherapy and explain why ATC is so highly fatal in such a short period of time. The authors of the study also discovered which specific markers thyroid stem cells express. With these observations it will soon be possible to identify tumors and target them in new therapeutic approaches. Carla Giordano, the head of the Molecular Endocrinology lab where the study was conducted said, “This discovery creates possibilities for treating not only anaplastic thyroid tumors, but also neoplastic thyroid tumors considered incurable due to their resistance to conventional therapies.”

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Hong Kong scientists say they have identified the cancer stem cells responsible for the spread of colorectal cancer to other organs and believe the find will revolutionise treatment.

Current treatments regard all cancer cells as alike, but the Hong Kong University researchers discovered that cancers contain a small number of stem cells responsible for starting and maintaining tumours.

“It will revolutionise the approach to cancer treatment in future,” one researcher, Ronnie Poon, told the South China Morning Post.

December 4, 2009- Working with mice, scientists at Johns Hopkins publishing in the December issue of Neoplasia have shown that a protein made by a gene called “Twist” may be the proverbial red flag that can accurately distinguish stem cells that drive aggressive, metastatic breast cancer from other breast cancer cells.

Building on recent work suggesting that it is a relatively rare subgroup of stem cells in breast tumors that drives breast cancer, scientists have surmised that this subgroup of cells must have some very distinctive qualities and characteristics.

In experiments designed to identify those special qualities, the Hopkins team focused on the gene “Twist” (or TWIST1) – named for its winding shape – because of its known role as the producer of a so-called transcription factor, or protein that switches on or off other genes. Twist is an oncogene, one of many genes we are born with that have the potential to turn normal cells into malignant ones.

“Our experiments show that Twist is a driving force among a lot of other players in causing some forms of breast cancer,” says Venu Raman, Ph.D., associate professor of radiology and oncology, Johns Hopkins University School of Medicine. “The protein it makes is one of a growing collection of markers that, when present, flag a tumor cell as a breast cancer stem cell.”

Previous stem cell research identified a Twist-promoted process known as epithelial-to-mesenchymal transition, or EMT, as an important marker denoting the special subgroup of breast cancer stem cells. EMT essentially gets cells to detach from a primary tumor and metastasize. The new Hopkins research shows that the presence of Twist, along with changes in two other biomarkers – CD 24 and CD44 – even without EMT, announces the presence of this critical sub-group of stem cells.
“The conventional thinking is that the EMT is crucial for recognizing the breast cancer cell as stem cells, and the potential for metastasis, but our studies show that when Twist shows up in excess or even at all, it can work independently of EMT,” says Farhad Vesuna, Ph.D., an instructor of radiology in the Johns Hopkins University School of Medicine. “EMT is not mandatory for identifying a breast cancer stem cell.”

Working with human breast cancer cells transplanted into mice, all of which had the oncogene Twist, the scientists tagged cell surface markers CD24 and CD44 with fluorescent chemicals. Following isolation of the subpopulation containing high CD44 and low CD24 by flow cytometry, they counted 20 of these putative breast cancer stem cells. They then injected these cells into the breast tissue of 12 mice. All developed cancerous tumors.

“Normally, it takes approximately a million cells to grow a xenograft, or transplanted tumor,” Vesuna says. “And here we’re talking just 20 cells. There is something about these cells – something different compared to the whole bulk of the tumor cell – that makes them potent. That’s the acid test – if you can take a very small number of purified “stem cells” and grow a cancerous tumor, this means you have a pure population.”

Previously, the team showed that 65 percent of aggressive breast cancers have more Twist compared to lower-grade breast cancers, and that Twist-expressing cells are more resistant to radiation.
Twist is what scientists refer to as an oncogene, one that if expressed when and where it’s not supposed to be expressed, causes oncogenesis or cancer because the molecules and pathways that once regulated it and kept it in check are gone.

This finding – that Twist is integral to the breast cancer stem cell phenotype – has fundamental implications for early detection, treatment and prevention, Raman says. Some cancer treatments may kill ordinary tumor cells while sparing the rare cancer stem cell population, sabotaging treatment efforts. More effective cancer therapies likely require drugs that kill this important stem cell population.

This study was supported by the Maryland Stem Cell Research Foundation.

In addition to Vesuna and Raman, authors of the paper include Ala Lisok and Brian Kimble, also of Johns Hopkins.

fonte http://www.hopkinsmedicine.org/Press_releases/2009/12_04_09.html

What are the biological processes that stem cells go through? What are the industrial processes we need to manufacturing? What do we know about cancer stem cells? How do iPS cells fit into the picture vs. embryonic stem cells? In this episode we investigate how the science and research of stem cells is being translated into industrial cell processes to create FDA approvable, and commercializable products. Differentiation, proliferation, migration, retro-differentiation, trans-differentiation, transformation into cancer cells, the role of tumors‘ micro environments and epigenetics and all reviewed here by the field’s foremost experts.

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