This mechanism underlies metabolic reprogramming that supports cellular adaptation under stress, highlighting Ap4A’s role as a metabolic “alarmone.” For instance, tumor cells—often residing in a hypoxic or nutrient-depleted microenvironment—leverage this adaptability through P2X7-mediated upregulation of glycolytic enzymes and more efficient utilization of intracellular glycogen stores [45]. Here, P2RX7 is linked to neoplasm.