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Archive - Aug 2009

Date

August 4th

New Cilia Disease Identified

Scientists have shown that a lethal developmental disorder (hydolethalus syndrome) belongs to an emerging class of human ciliopathic disorders that includes polycystic kidney disease. "Five years ago, a human genetics study linked hydrolethalus syndrome to a mutation in a protein named HYLS1. Since this discovery, the function of HYLS1 has remained unknown. Our work solves this mystery, showing that HYLS1 is a centriolar protein required for the formation of cilia, small hair-like cellular projections that execute a variety of essential motile and sensory functions," explained Dr. Karen Oegema, an author of the study. Hydrolethalus syndrome is a rare genetic disorder characterized by severe birth defects (hydrocephalus, polydactyly, cardio/pulmonary malformations) that result in stillbirth or early neonatal death. The majority of cases affect people of Finnish ancestry, where the incidence is roughly 1 in 20,000. In the current work, Dr. Oegema and colleagues showed that the evolutionarily conserved HYLS1 protein is, in fact, a centriolar protein that is specifically required for cilia formation in both C. elegans and vertebrates. The researchers demonstrated that HYLS1 stably incorporates into centrioles during their assembly, and plays a crucial role in the early steps of the ciliogenesis pathway. Interestingly, however, HYLS1 is dispensable for centriole assembly and centrosome function during cell division. This work is reported in the September 1 issue of Genes & Development. [Press release]

August 3rd

Heat-Based Procedure Using Nanotubes Kills Tumor Cells

Researchers have shown that the by injecting man-made nanotubes into tumors and then heating them with a quick, 30-second burst of laser radiation, they can kill nearly 80 percent of kidney tumors in mice. The researchers said that the finding suggests a potential future cancer treatment for humans. Nanotubes are long, thin, sub-microscopic tubes made of carbon. For the study, researchers used multi-walled nanotubes (MWCNTs), which contain several nanotubes nested within each other. The tubes, when non-invasively exposed to laser-generated near-infrared radiation, respond by vibrating, creating heat. If enough heat is conducted, tumor cells near the tubes begin to shrink and die. In the mice that received the MWCNTs followed by a 30-second laser treatment, researchers found that the higher the quantity of nanotubes injected, the longer the mice lived and the less tumor regrowth was seen. In fact, in the group that received the highest dose of MWCNTs, tumors completely disappeared in 80 percent of the mice. Many of those mice continued to live tumor-free through the completion of the study, which was about nine months later. "MWCNTs are more effective at producing heat than other investigational nanomaterials," saqid Dr. Suzy Torti, lead investigator for the study. "Because this is a heat therapy rather than a biological therapy, the treatment works on all tumor types if you get them hot enough. We are hopeful that we will be able to translate this into humans." This work was published in PNAS in August. [Press release]