Tag Archives: nature

Study identifies population of stem-like cells where HIV persists in spite of treatment

"Most human cells are short lived, so it has been unclear how HIV manages to stick around for decades in spite of very effective antiviral treatment," says Mathias Lichterfeld, MD, of the MGH Infectious Disease Division, corresponding author of the report receiving advance online publication in Nature Medicine. "This question led to the hypothesis that HIV might infect stem cells — the most long-lasting cells in the body — but traditional organ-specific stem cells, even those that give rise to all immune and blood cells, are resistant to HIV infection. We have discovered that a new group of T cells, called T memory stem cells, are susceptible to HIV and likely represent the longest lasting cellular niche for the virus." HIV has such a devastating impact on the human immune system because it infects the CD4-positive T cells that normally direct and support the infection-fighting activities of other immune cells. Several subtypes of CD4 T cells have different functions; and all are capable of being infected by HIV, although antiviral treatment keeps the virus in those cells from replicating…

Mutation discovery may improve treatment for rare brain tumor type

The discovery, reported in Nature Genetics, is encouraging, because it may be possible to attack the tumors with targeted drugs already in use for other kinds of tumors, said the investigators from Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, Massachusetts General Hospital, and the Broad Institute of MIT and Harvard. The mutated gene, known as BRAF, was found in almost all samples of tumors called papillary craniopharyngiomas. This is one of two types of craniopharyngiomas — the other being adamantinomatous — that develop in the base of the brain near the pituitary gland, hypothalamus, and optic nerves. The papillary craniopharyngiomas occur mainly in adults; adamantinomatous tumors generally affect children. …

Mechanism affecting risk of prostate cancer found

Prostate cancer is the most commonly diagnosed malignancy and the second most common cause of cancer-related deaths in men worldwide. In Finland, more than 4,000 new cases are diagnosed every year. The human genome is mainly identical throughout the human population worldwide. However, millions of small variations or polymorphisms, often located in a single nucleotide, can be found between individuals. …

Scientists control cells following transplantation, from inside out

Associate Professor Jeffrey Karp, PhD, and James Ankrum, PhD, demonstrate in this month’s issue of Nature Protocols how to load cells with microparticles that provide the cells cues for how they should behave over the course of days or weeks as the particles degrade. "Regardless of where the cell is in the body, it’s going to be receiving its cues from the inside," said Karp, a Harvard Stem Cell Institute Principal Faculty member at Brigham and Women’s Hospital. "This is a completely different strategy than the current method of placing cells onto drug-doped microcarriers or scaffolds, which is limiting because the cells need to remain in close proximity to those materials in order to function. Also these types of materials are too large to be infused into the bloodstream." Cells are relatively simple to control in a Petri dish. …

Researchers discover ovarian cancer biomarker

A CWRU research team led by Analisa DiFeo, an assistant professor of General Medical Science-Oncology at the Case Comprehensive Cancer Center, found that the biomarker miR-181a is a molecular driver of epithelial ovarian cancer (EOC). The research team also found that elevated levels of miR-181a in ovarian tumors are associated with chemotherapy resistance and disease progression. "By looking at the expression of this microRNA in tumor samples, we get an idea which women may respond to standard chemotherapy and which are at a high risk for recurrence," DiFeo said. "This helps guide treatment decisions and improve survival rates." In the past, researchers have been unable to predict how EOC patients will respond to treatment…

Stopping tumors in their path

A GBM tumour contains a complex combination of different cell types, including ‘stem-like’ cells that are able to initiate brain tumour growth, even when present in very small numbers. These cells, known as brain-tumour initiating cells (BTICs), are believed to be among the cells that can re-initiate GBM if they are not completely eradicated through surgery, radiation and chemotherapy. Thus, BTICs represent an important therapeutic target for GBM treatment strategies. "We wanted to find out how GBM-derived BTICs are able to initiate a tumour with the ultimate goal of preventing the re-growth of this deadly form of brain cancer," says Dr…

Animal vaccine study yields insights that may advance HIV vaccine research

By examining both viral amino-acid sequences and the animals’ immune responses, the scientists could determine the mechanisms of protection from SIV infection. The study demonstrated that antibodies to the virus spikes that SIV uses to infect cells are necessary and sufficient to prevent SIV infection. The study also identified clear measures of immune responses in monkeys that predict protection from SIV infection. Amid the genetically heterogeneous mix of SIV to which the vaccinated monkeys were exposed, vaccine-induced immune responses tended to block infection by those viruses sensitive to neutralization by SIV antibodies, while neutralization-resistant forms of SIV tended to cause infection. …

Blocking tumor-associated macrophages decreases glioblastoma’s growth, extends survival in mice

The rates of apoptosis, or programmed cell death, were higher in the mice treated with the experimental agent than in the untreated animals that also had high-grade glioblastomas, said Johanna Joyce, Ph.D., of the Memorial Sloan-Kettering Cancer Center (MSKCC) in New York City. …

Geme mutation potential target for diagnosis, treatment of insulinoma

Pancreatic neuroendocrine tumors are classified into functional and nonfunctional tumors by hormone secretion and clinical symptoms. Functional PNETs are mainly represented by insulinoma, which secrete insulin independent of glucose and cause hypoglycemia. The major genetic alterations in insulinomas are still unknown. …