New insight into cell development and cancer

Dec. 27, 2012 ? Long-standing research efforts have been focused on understanding how stem cells, cells capable of transforming into any type of cell in the body, are capable of being programmed down a defined path to contribute to the development of a specific organ like a heart, lung, or kidney. Research from the University of North Carolina at Chapel Hill School of Medicine has shed new light on how epigenetic signals may function together to determine the ultimate fate of a stem cell.

The study, published December 27, 2012 by the journal Molecular Cell, implicates a unique class of proteins called polycomb-like proteins, or PCL's, as bridging molecules between the "on" and "off" state of a gene. While all of these specialized types of cells share the same genetic information encoded in our DNA, it is becoming increasingly clear that information outside the genome, referred to as epigenetics, plays a central role in orchestrating the reprogramming of a stem cell down a defined path.

Although it is understood that epigenetics is responsible for turning genes "on" and "off" at defined times during cellular development, the precise mechanisms controlling this delicate process are less well understood.

"This finding has important implications for both stem cell biology and cancer development, as the same regulatory circuits controlled by PCL's in stem cells are often misregulated in tumors," said Dr. Greg Wang, senior author of the study and Assistant Professor of Biochemistry and Biophysics in the UNC School of Medicine and a member of UNC Lineberger Comprehensive Cancer Center.

The study, led by postdoctoral research fellows Drs. Ling Cai and Rui Lu in the Wang lab, and Dr. Scott Rothbart, a Lineberger postdoctoral fellow in the lab of Dr. Brian Strahl, Associate Professor of Biochemistry and Biophysics in the UNC School of Medicine and a member of UNC Lineberger Comprehensive Cancer Center, identified that PCL's interact with an epigenetic signal associated with genes that are turned on to recruit a group of proteins called the PRC2 complex which then turn genes off.

"In stem cells, the PRC2 complex turns genes off that would otherwise promote reprogramming into specialized cells of organs like the heart or lungs," said Wang.

In addition to its fundamental role in cellular development, elevated levels of PRC2 have been found in cancers of the prostate, breast, lung, and blood, and pharmaceutical companies are already developing drugs to target PRC2. Wang and colleagues determined that the same mechanisms controlling PRC2 function in stem cells also applies in human cancers.

"The identification of a specific PCL in controlling PRC2 in cancer cells suggests we may be able to develop drugs targeting this PCL to regulate PRC2 function in a more controlled manner that may maintain PRC2 function in stem cells while inhibiting it in the tumor," said Wang.

This research was funded by the National Institutes of Health grants (GM085394 and GM068088), the Department of Defense, the V Foundation for Cancer Research, and the University Cancer Research Fund, and was performed in collaboration with scientists at the University of California at Riverside, Rockefeller University, Memorial Sloan-Kettering Cancer Center, and the Albert Einstein College of Medicine. Study co-authors from UNC also included Bowen Xu, a student in the Wang Lab, and Ashutosh Tripathy, a Research Professor in the Department of Biochemistry and Biophysics.

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The above story is reprinted from materials provided by University of North Carolina Health Care.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/~3/g5nZCwhyrsQ/121227130323.htm

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Tourists Visiting Tikal During Maya Celebrations Damage Ruins

Tikal, Guatemala

A mayan shaman takes part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

View of an offering made of cacao, candles, cigars, and ocote wood during a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Guatemalan natives and tourists take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Guatemalan natives and visitors take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Guatemalan indigenous women take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Mayan shamans take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Mayan shamans take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Mayan shamans and indigenous people take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

Mayan shamans take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Tikal, Guatemala

A mayan shaman takes part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age at Tikal archaeological site, Peten departament, 560 km north of Guatemala City.

Tikal, Guatemala

An indigenous man kisses a bunch of candles for an offering during in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Bogot?, Colombia

A woman takes part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Bogot?, Colombia

People take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Bogot?, Colombia

A woman takes part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Cop?n, Honduras

Indigenous people take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Tikal, Guatemala

Mayan shamans take part in a ceremony on December 21, 2012, celebrating the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City.

Cop?n, Honduras

Indigenous people take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Cop?n, Honduras

Indigenous people take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Bogot?, Colombia

A man takes part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Cop?n, Honduras

Visitors meditate during celebrations for the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in the Copan archaeological park, 400km northwest of Tegucigalpa.

Bogot?, Colombia

A woman takes part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Bogot?, Colombia

People take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Bogot?, Colombia

People take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, at Bogota's main square, Colombia.

Cop?n, Honduras

Indigenous people take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Cop?n, Honduras

Indigenous people take part in a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Cop?n, Honduras

An indigenous woman holds candles during a ceremony to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the Maya new age, on December 21, 2012, in Las Sepulturas --a Mayan residential site--, in the surroundings of the Copan archaeological site, 400km northwest of Tegucigalpa.

Tikal, Guatemaa

Members of a folkloric group perform during celebrations marking the end of the Mayan age, December 20, 2012 at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City. Ceremonies are being held to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the new Maya Era on December 21.

Tikal, Guatemala

Guatemalan President Otto Perez Molina waves during celebrations marking the end of the Mayan age at the Tikal archaeological site, Peten departament, 560 kms north of Guatemala City, on December 20, 2012. Ceremonies will be held here to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the new Maya Era on December 21.

Cop?n, Honduras

Guatemalan chaman Christian Nottbohn (C) holds a Mayan ceremony in Rastrajon, once a settlement of warriors destined to protect the ancient city of Copan, in Copan archeological park, some 400 kms northwest of Tegucigalpa, on December 20, 2012. Ceremonies will be held to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the new Maya Era on December 21.

Cop?n, Honduras

Guatemalan chaman Christian Nottbohn (C) holds a Mayan ceremony in Rastrajon, once a settlement of warriors destined to protect the ancient city of Copan, in Copan archeological park, some 400 kms northwest of Tegucigalpa, on December 20, 2012. Ceremonies will be held to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the new Maya Era on December 21. AFP PHOTO / Orlando SIERRA (Photo credit should read ORLANDO SIERRA/AFP/Getty Images)

Tikal, Guatemala

View 'Gran Jaguar' Mayan temple at the Tikal archaeological site in Peten departament, 560 kms north of Guatemala City, on December 20, 2012. Ceremonies will be held here to celebrate the end of the Mayan cycle known as Bak'tun 13 and the start of the new Maya Era on December 21.

Source: http://www.huffingtonpost.com/2012/12/27/tourists-visiting-tikal-d_n_2369674.html

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