Figure 6. Two different growth schemes of tumor spheroids (gray filled circle) with same initial size in response to fluctuating and steady glucose (green solid line).

(A) Cycle of growth and invasion in response to fluctuating glucose. Tumor cells (blue filled circle) at the surface of the spheroid begin to migrate away from the core when miR-451 levels are low (blue solid line; high AMPK activity) due to low glucose. These migratory cells become proliferative cells when high glucose is introduced and miR-451 levels are high (red solid line; low AMPK activity). (B) Monotonic growth due to steady supply of glucose; the total supply of glucose is the same as in (A). We hypothesize that tumor spheroids with fluctuating glucose in (A) will grow faster than ones grown in steady glucose supply in (B).