How Temperature and Saliva Affect Oral Cancer Cells

Oral cancer often appears in a specific area of the mouth, shaped like a U. This area includes the floor of the mouth, the sides of the tongue, and the back part near the tonsils. Scientists are still trying to figure out why this happens and how cells in this area deal with changes in temperature and the liquid they come into contact with. Inside cells, there are tiny structures called biomolecular condensates. These structures don't have a membrane and can change shape and function based on different conditions. In oral cancer cells, these condensates can disassemble and reassemble quickly when exposed to liquids that are less salty than the cells, like saliva or drinks such as water, tea, or coffee. This process happens at body temperature, around 37°C. Scientists wanted to know if temperature affects this process. They found that at a colder temperature, around 5°C, the cycle of disassembly and reassembly slowed down. At a warmer temperature, around 50°C, the cycle sped up. This suggests that the temperature of the liquids we consume might impact how these condensates behave in oral cells. The researchers also looked at a specific pathway in cells called the WNK-SPAK/OSR1 pathway. This pathway is known to regulate the flow of water and certain minerals in kidney cells. They used different inhibitors to see how this pathway affects the condensates in oral cells. They found that inhibiting the WNK part of the pathway stopped the condensates from disassembling when exposed to less salty liquids. Inhibiting the SPAK/OSR1 part slowed down the reassembly process. Interestingly, one of the inhibitors, WNK-IN-11, caused the condensates to change shape quickly, turning from spheres to fibers. However, this change did not affect the antiviral function of the protein involved, GFP-MxA. These findings suggest a new idea about why oral cancer often appears in the U-shaped area of the mouth. It might be due to the repetitive exposure to changes in temperature and the saltiness of liquids, which could lead to changes in the condensates and potentially contribute to cancer development.