 |
|
Cell division studies hint at future cancer therapy
January 23, 2008When a cell's assets get divided between daughter cells, Dr. Quansheng Du wants to make sure both offspring do well.
He's dissecting the complex, continuous and amazing process that enables one cell to become two.
When all goes well, cell division, or mitosis, helps repopulate a damaged organ or replenish endogenous stem cells.
When it goes badly, it can result in cancer or developmental defects.
"What we are trying to understand is how cells divide," says Dr. Du, cell biologist at the Medical College of Georgia, who recently received $2 million in grants from the National Institutes of Health and the American Cancer Society to pursue his studies.
He focuses on the mitotic spindle, a sort of demarcation line that helps a dividing cell divvy up its genetic information. Once a cell decides to divide, it duplicates its genetic material and the nuclear envelope containing the material dissolves. Microtubules, stick-like projections that look like spokes on a wheel, start moving, reorganizing into a spindle-shaped structure that attaches and aligns the genetic material at the center of the spindle. The cell, sensing the microtubule attachment, initiates a process that pulls the duplicated genetic material apart.
The outcome of normal cell division is typically two cells that look just like the original. In a culture dish and in humans, the process takes about an hour.
Not every cell can divide. Terminally differentiated cells, such as neurons and muscle cells, can't.
However, stem cells, known for their flexibility, divide well and at least three ways. They can divide genetic material evenly, forming two identical stem cells. They can undergo asymmetric cell division, birthing one identical stem cell as well as a new daughter cell that differentiates into another cell type, such as a skin cell or neuron. They can even make two uniquely differentiated cells, thus depleting the stem cell.
During mammalian development and tissue maintenance, stem cells are constantly balancing between self-renewal and differentiation by adapting different types of cell division.
While a postdoctoral fellow at the University of Virginia, Dr. Du was studying cell polarity, essential to asymmetric cell division because it attracts so-called cell fate determinants to one side of the mother cell and directs spindle orientation.
In work published in Nature Cell Biology, Current Biology and Cell, he detailed a group of proteins critical for spindle organization and positioning in mammalian cells.
These proteins may help determine cell fate after asymmetric cell division as well, he says: for example, determining whether the daughter cells keep being stem cells or differentiate into another cell type.
Now, he wants to know how these proteins get where they need to be and how they cooperate with other proteins to organize the spindle and direct its orientation.
These details may eventually lead to better cancer treatment, such as disrupting mitotic spindle organization so cancer cells cannot divide, Dr. Du says.
The relatively recent discoveries of cancer stem cells make the possibilities even more intriguing.
"The current cancer stem cell theory is that it's actually just a small population of cells within the tumor that are the original cancer-initiating cells," says Dr. Du. Still if each cancer stem cell in that small population divides, the numbers add up quickly.
"How normal stem cells become cancer stem cells is not clear," he says. "Abnormal asymmetric stem cell division, which will break the balance between stem cell self-renewal and differentiation, may be an early event that drives the development of cancer stem cells."
Understanding the mechanisms of stem cell division will provide clues for targeted cancer therapy against these cancer stem cells. Manipulating the balance toward differentiation, for example, would probably lead to the depletion of cancer stem cells, Dr. Du says.
Medical College of Georgia
When it goes badly, it can result in cancer or developmental defects.
"What we are trying to understand is how cells divide," says Dr. Du, cell biologist at the Medical College of Georgia, who recently received $2 million in grants from the National Institutes of Health and the American Cancer Society to pursue his studies.
He focuses on the mitotic spindle, a sort of demarcation line that helps a dividing cell divvy up its genetic information. Once a cell decides to divide, it duplicates its genetic material and the nuclear envelope containing the material dissolves. Microtubules, stick-like projections that look like spokes on a wheel, start moving, reorganizing into a spindle-shaped structure that attaches and aligns the genetic material at the center of the spindle. The cell, sensing the microtubule attachment, initiates a process that pulls the duplicated genetic material apart.
The outcome of normal cell division is typically two cells that look just like the original. In a culture dish and in humans, the process takes about an hour.
Not every cell can divide. Terminally differentiated cells, such as neurons and muscle cells, can't.
However, stem cells, known for their flexibility, divide well and at least three ways. They can divide genetic material evenly, forming two identical stem cells. They can undergo asymmetric cell division, birthing one identical stem cell as well as a new daughter cell that differentiates into another cell type, such as a skin cell or neuron. They can even make two uniquely differentiated cells, thus depleting the stem cell.
During mammalian development and tissue maintenance, stem cells are constantly balancing between self-renewal and differentiation by adapting different types of cell division.
While a postdoctoral fellow at the University of Virginia, Dr. Du was studying cell polarity, essential to asymmetric cell division because it attracts so-called cell fate determinants to one side of the mother cell and directs spindle orientation.
In work published in Nature Cell Biology, Current Biology and Cell, he detailed a group of proteins critical for spindle organization and positioning in mammalian cells.
These proteins may help determine cell fate after asymmetric cell division as well, he says: for example, determining whether the daughter cells keep being stem cells or differentiate into another cell type.
Now, he wants to know how these proteins get where they need to be and how they cooperate with other proteins to organize the spindle and direct its orientation.
These details may eventually lead to better cancer treatment, such as disrupting mitotic spindle organization so cancer cells cannot divide, Dr. Du says.
The relatively recent discoveries of cancer stem cells make the possibilities even more intriguing.
"The current cancer stem cell theory is that it's actually just a small population of cells within the tumor that are the original cancer-initiating cells," says Dr. Du. Still if each cancer stem cell in that small population divides, the numbers add up quickly.
"How normal stem cells become cancer stem cells is not clear," he says. "Abnormal asymmetric stem cell division, which will break the balance between stem cell self-renewal and differentiation, may be an early event that drives the development of cancer stem cells."
Understanding the mechanisms of stem cell division will provide clues for targeted cancer therapy against these cancer stem cells. Manipulating the balance toward differentiation, for example, would probably lead to the depletion of cancer stem cells, Dr. Du says.
Medical College of Georgia
Stem Cells Current Events and Stem Cells News RSSMayo researchers explore issues related to multiple myeloma treatment
Multiple myeloma (MM) is a cancer of plasma cells that affects approximately 3 in 100,000 people each year. Although there is no cure for this disease, researchers have developed treatments that help relieve pain, control complications, and slow the progress of MM in many patients.
Reversible 3-D cell culture gel invented
Singapore's Institute of Bioengineering and Nanotechnology (IBN), which celebrates its fifth anniversary this year, has invented a unique user-friendly gel that can liquefy on demand, with the potential to revolutionize three-dimensional (3D) cell culture for medical research.
The small cell neuroendocrine carcinoma of the ampulla of vater
Ampullary small cell neuroendocrine carcinoma is extremely rare and has only been documented in few case reports and retrospective study. The patients with ampullary small cell neuroendocrine carcinoma usually presented after the age of 60 years, and a male predilection was observed.
Researchers Find an Essential Gene for Forming Ears of Corn
Cold Spring Harbor Laboratory (CSHL) professor David Jackson, Ph.D., and a team of plant geneticists have identified a gene essential in controlling development of the maize plant, commonly known in the United States as corn.
Pittsburgh researchers identify source of multipotent stem cells with broad regenerative potential
In a promising finding for the field of regenerative medicine, stem cell researchers at Children's Hospital of Pittsburgh of UPMC have identified a source of adult stem cells found on the walls of blood vessels with the unlimited potential to differentiate into human tissues such as bone, cartilage and muscle.
Healthy blood vessels may prevent fat growth
The cells lining blood vessels are known to be important for maintaining health, but researchers at the Indiana University School of Medicine believe these cells may perform an unsuspected task - controlling the development of fat cells.
UNC scientists turn human skin cells into insulin-producing cells
Researchers at the University of North Carolina at Chapel Hill School of Medicine have transformed cells from human skin into cells that produce insulin, the hormone used to treat diabetes.
Stem cells may solve mystery of early pregnancy breast cancer protection
The answer to why an early pregnancy seems to protect against breast cancer could rest with a decrease in stem cells found after animals have given birth, said researchers at Baylor College of Medicine in a report that appears in the current issue of the journal Stem Cell.
Scientists identify genes capable of regulating stem cell function
Scientists from The Forsyth Institute, Boston, MA, and the Howard Hughes Medical Institute at the University of Utah School of Medicine have developed a new system in which to study known mammalian adult stem cell disorders.
Embryonic stem cells might help reduce transplantation rejection
Researchers have shown that immune-defense cells influenced by embryonic stem cell-derived cells can help prevent the rejection of hearts transplanted into mice, all without the use of immunosuppressive drugs.
More Stem Cells Current Events and Stem Cells News Articles
 | Sex, Science, and Stem Cells by Diana DeGette In August 2001, President George W. Bush announced with fanfare that federal funds would be made available to scientists conducting research on human embryonic stem cell lines—with restrictions. Reading his words, not his lips, was Congresswoman Diana DeGette of Colorado’s First Congressional District, and what she read was this: a ban. “As a practical matter,” scientists could no longer... |
 | The Human Embryonic Stem Cell Debate: Science, Ethics, and Public Policy (Basic Bioethics) CHOICE Outstanding Academic Book for 2002 Human embryonic stem cells can divide indefinitely and have the potential to develop into many types of tissue. Research on these cells is essential to one of the most intriguing medical frontiers, regenerative medicine. It also raises a host of difficult ethical issues and has sparked great public interest and controversy. This book offers a... |
 | The Stem Cell Controversy: Debating the Issues (Contemporary Issue Series) Stem cell research is headline news. Researchers are eager to move forward, state governments and private foundations are rushing to support it, and the sick and afflicted are desperate for its benefits. Yet powerful forces in our society—led by President George W. Bush—find it morally troubling and they are doing all in their powers to restrict its development beyond a very limited scale. ... |
 | Stem Cell Now by Christopher Thomas Scott The essential account of the most important scientific advance—and most volatile ethical debate—of our time While many believe stem cell research holds the key to curing a wide range of ailments, others see this research as opening a Pandora’s box that will devalue human life. In Stem Cell Now, Christopher Scott—executive director of Stanford University’s Stem Cells and Society... |
 | Essentials of Stem Cell Biology by Robert Lanza, E. Donnall Thomas, James Thomson, Roger Pedersen, John Gearhart, Brigid Hogan, Douglas Melton, Michael West This abridged version of the bestselling reference Handbook of Stem Cells, Two-Volume Set attempts to incorporate all the essential subject matter of the original two-volume edition in a single volume. The material has been reworked in an accessible format suitable for students and general readers interested in following the latest advances in stem cells, including full color presentation... |
 | The Stem Cell Divide: The Facts, the Fiction, and the Fear Driving the Greatest Scientific, Political, and Religious Debate of Our Time by Michael Bellomo There has been much recent debate about the merits, dangers, and nature of stem cell research. Some see in it the answer to every debilitating disease known to man, while others see it as a step away from human cloning. While the battle has raged, research is moving ahead, and California has already passed a measure that will give $3 billion in support to stem cell research. But as politics,... |
 | The Stem Cell Dilemma: Beacons of Hope or Harbingers of Doom? by Leo Furcht, William Hoffman TodayÕs scientists are showing us how stem cells create and repair the human body. Unlocking these secrets has become the new Holy Grail of biomedical research. But behind that search lies a sharp divide. Stem cells offer the hope of creating or repairing tissues lost to age, disease, and injury. Yet because of this ability, stem cells hold the potential to incite an international biological... |
 | Fundamentals of the Stem Cell Debate: The Scientific, Religious, Ethical, and Political Issues Few recent advances in science have generated as much excitement and controversy as human embryonic stem cells. The potential of these cells to replace diseased or damaged cells in virtually every tissue of the body heralds the advent of an extraordinary new field of medicine. Controversy arises, however, because current techniques required to harvest stem cells involve the destruction of the... |
 | Stem Cell Research: Medical Applications And Ethical Controversy (The New Biology) by Joseph, Ph.D. Panno |
 | Stem Cell Century: Law and Policy for a Breakthrough Technology by Russell Korobkin The explosion of interest in stem cell research raises a raft of controversial policy questions. When should human embryos be used to create stem cells? Should cloning be outlawed? Should egg and tissue donors be paid? Should we allow scientists to patent stem cells? Is the government entitled to a portion of the revenue from stem cell technology created with public funds? How should the... |
| © 2008 BrightSurf.com |