Stories about: microenvironment

Turning tumors against themselves to stop metastasis

Tumor cells need the right environment in order to spread. But a protein that some tumors themselves produce can make some environments inhospitable to metastasis. (Albh/Wikimedia Commons)
With cancer, it’s generally not the primary tumor that kills people, but metastasis—the spread of cancer to locations far from the original tumor.

Finding ways of stopping metastasis has proven immensely challenging. On some level, it’s a problem with the models that we use to study metastatic cancer. But it’s also a matter of understanding why particular tumor types spread where they do—like prostate tumors to the bones or breast cancer to the brain—and what about the microenvironment—the combination of cells, proteins and other factors—makes different sites in the body metastatically friendly to different tumors.

Randolph Watnick, PhD, and his research team in Boston Children’s Vascular Biology Program have been asking this question, and in the process have found that a protein called prosaposin can make sites unfriendly to metastasis. Interestingly, it’s a protein that some tumors actually make themselves.

But even better, Watnick has found that a tiny fragment of prosaposin—a peptide that is a mere five amino acids long—has the same anti-metastatic power of the full protein, making it highly attractive for drug development. He and his collaborators reported the full story in a recent paper in the journal Cancer Discovery.

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Mimicking milieus to produce platelets…for science and transfusion

Researchers and doctors dream of being able to artificially produce platelets (in the blood bag above) at clinically useful scales. A device that mimics the environments in which platelets mature could help them get there. (Toytoy/Wikimedia Commons)

The platelet – a crucial cog in our blood’s clotting machinery – is in high demand. Trauma, chemotherapy, and surgery patients often need platelet transfusions to keep their blood working properly. So too do people with genetic disorders like Wiskott-Aldrich syndrome that prevent them from producing enough platelets on their own and cause thrombocytopenia.

However, platelets are in short supply compared to other blood products, in part due to their short shelf life.

“Platelets only last in the body for about 10 days at a time,” explains Jonathan Thon, a fellow in the laboratory of Joe Italiano, a member of Children’s Vascular Biology Program. “In a blood bank, red blood cells can be stored in a refrigerator for 42 days, and plasma can be frozen for years. But platelets need to be stored at room temperature, and only for a short time for fear of bacterial contamination.” Which means that few platelets are available for those who need them – a situation that screams for a means of artificial platelet production.

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