Tag Archives: process

Scientist uncovers internal clock able to measure age of most human tissues; Women’s breast tissue ages faster than rest of body

While earlier clocks have been linked to saliva, hormones and telomeres, the new research is the first to identify an internal timepiece able to accurately gauge the age of diverse human organs, tissues and cell types. Unexpectedly, the clock also found that some parts of the anatomy, like a woman’s breast tissue, age faster than the rest of the body. "To fight aging, we first need an objective way of measuring it. …

‘Phenotype switching’ can make melanoma become metastatic, resistant to drugs

The findings were published in the journal Cancer Discovery and are currently available online. "We were able to demonstrate for the first time that different receptors within a single signaling pathway — in this case, the Wnt signaling pathway — can guide the phenotypic plasticity of tumor cells, and increased signaling of Wnt5A in particular can result in an increase in highly invasive tumor cells that are less sensitive to existing treatments for metastatic melanoma," said Ashani Weeraratna, Ph.D., assistant professor in the Tumor Microenvironment and Metastasis Program of Wistar’s NCI-designated Cancer Center, and senior corresponding author on the manuscript. …

New imaging technique can identify breast cancer subtypes, early treatment response

"The process of targeted drug development requires assays that measure drug target engagement and predict the response (or lack thereof) to treatment," said Alex Walsh, a graduate student in the Department of Biomedical Engineering at Vanderbilt University in Nashville, Tenn. "We have shown that optical metabolic imaging (OMI) enables fast, sensitive, and accurate measurement of drug action. Importantly, OMI measurements can be made repeatedly over time in a live animal, which significantly reduces the cost of these preclinical studies." Human cells undergo extensive chemical reactions called metabolic activity to produce energy, and this activity is altered in cancer cells. When cancer cells are treated with anticancer drugs, their metabolic activity changes. …

New role for cell dark matter in genome integrity

Each time a cell divides, chromosomes, the long DNA molecules that encode our genes, must be duplicated. But the machinery that does this replication is imperfect, failing to perform duplication all the way to the ends of chromosomes. How living cells divide and how this process is accurately achieved are among the deepest questions scientists have been addressing for decades. …

Sparing the body, breast cancer treatment via nipple injection

“Local delivery of therapeutic agents into the breast, through intra-nipple injection, could diminish the side effects typically observed with systemic chemotherapy—where the toxic drugs pass through all of the tissues of the body,” said Dr. Silva Krause, one of the researchers behind the experiment, “It also prevents drug breakdown by the liver, for example, which can rapidly reduce effective drug levels.” According to Silva, she and her colleagues have already begun experimentation in applying the method. “The authors have utilized this technique to inject a new nanoparticle-based therapeutic that inhibits a specific gene that drives breast cancer formation,” said Silva, “This targeted treatment was shown to prevent cancer progression in mice that spontaneously develop mammary tumors, [and] is currently in review in Science Translational Medicine.” In order to better communicate their procedure, Silva and her colleagues decided to publish with JoVE. …

New approach to treating human brain cancer could lead to improved outcomes

The research team, led by Robert Wechsler-Reya, Ph.D., professor in Sanford-Burnham’s NCI-Designated Cancer Center and director of the Tumor Initiation and Maintenance Program, discovered that the medulloblastoma cancer cells responsible for tumor growth and progression (called cancer stem cells or tumor-propagating cells — TPCs) divide more quickly than normal cells. Correspondingly, they have higher levels of certain enzymes that regulate the cell cycle (Aurora and Polo-like kinases). By using small-molecule inhibitors to stop the action of these enzymes, the researchers were able to block the growth of tumor cells from mice as well as humans…

Microfluidic platform gives clear look at a crucial step in cancer metastasis

While the initial process by which cancer cells enter the bloodstream — called intravasation — is well characterized, how cells escape blood vessels to permeate other tissues and organs is less clear. This process, called extravasation, is a crucial step in cancer metastasis. Now researchers at MIT have developed a microfluidic device that mimics the flow of cancer cells through a system of blood vessels…

Cell memory mechanism discovered

The DNA in human cells is translated into a multitude of proteins required for a cell to function. When, where and how proteins are expressed is determined by regulatory DNA sequences and a group of proteins, known as transcription factors, that bind to these DNA sequences. Each cell type can be distinguished based on its transcription factors, and a cell can in certain cases be directly converted from one type to another, simply by changing the expression of one or more transcription factors. It is critical that the pattern of transcription factor binding in the genome be maintained…

A more nuanced genetic code: Rules governing expression of developmental genes in embryonic stem cells

This paradoxical state — akin to figuring out how to navigate a red and green traffic signal — has since undergone scrutiny by labs worldwide. What has been postulated is that the control regions (or promoters) of some genes, particularly those critical for development during the undifferentiated state, stay "poised" for plasticity by communicating with both activating and repressive histones, a state biologists term "bivalency." A study by researchers at the Stowers Institute for Medical Research now revisits that notion. In this week’s advance online edition of the journal Nature Structural and Molecular Biology, a team led by Investigator Ali Shilatifard, Ph.D., identifies the protein complex that implements the activating histone mark specifically at "poised" genes in mouse embryonic stem (ES) cells, but reports that its loss has little effect on developmental gene activation during differentiation. …