Real Time Pharmacology

Cancer cells tend to turn their extracellular environment acidic, thus helping these rogue cells thrive while creating a hostile environment for normal ones. Acidosis promotes tumor growth, metastasis and drug resistance, while helping tumor cells evade the immune system. But it’s not clear exactly how this occurs.   Using a fluorescently-labeled peptide called pHLIP that only inserts itself into the membranes of cells under acidic conditions, they mapped the acidic regions of mammary tumors produced by human breast cancer cell lines in mice. The pH probe provided striking images, for the first time at cell-level resolution, that confirmed what  previous methods  had suggested: acidosis is not confined to the hypoxic tumor core, but rather extends to the boundary between tumors and healthy tissue.  Called the tumor-stroma interface, this boundary is the advancing edge of a malignant tumor, where cells spread aggressively and break into blood vessels and nearb...