Effect of Low pH Treatment on Cell Cycle and Cell Growth

Cancer growth affects the pH of microenvironment that becomes acidified and supports local invasion. Studies have reported that pH is a factor in cancer growth, division, and spread. Although cancer cells produce low extracellular pH (6.5–6.9), they are able to maintain their intracellular pH at favorable ranges (7.2–7.4). Our preliminary results showed that growth of cancer cells changes after low pH treatment. The objective of our research is to study how low pH affects cell morphology and behavior. In my preliminary experiments, HeLa cells were incubated with low pH solution for 10 min and harvested using trypsin into medium with normal pH. After 24 hours in culture, cell number was assessed using Trypan Blue Exclusion Assay. As a result, low pH treated group doubled 1.4 times; whereas control group doubled 2.3 times, suggesting a division latency in low pH treated group on Day 1. Cell morphology on Day 1 was recorded as images and was categorized into round, spindle, triangle, and irregular groups, among which spindle cells were likely to be at G1 phase. Percentage of the spindle cells gradually increased during 16–24 hours in experimental group; however, in control group, percentage of spindle cells decreased, suggesting that low pH had induced cell cycle arrest at G1 phase. In conclusion, low pH treatment affects cell growth potentially through G1 cell cycle arrest. Future work is to confirm cell cycle arrest at G1 phase after low pH treatment and to study the mechanism of low pH effect on cancer cell growth. Support or Funding Information Funding is provided partially by NIH (#NS081629) to YVL. Thanks to the Osteopathic Heritage Foundations, Graduate Assistantship Program at Ohio University Heritage College of Osteopathic Medicine for supporting graduate student YH. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .