2 research outputs found
Mass measurements during lymphocytic leukemia cell polyploidization decouple cell cycle- and cell size-dependent growth
Cell size is believed to influence cell growth and metabolism.
Consistently, several studies have revealed that large cells have
lower mass accumulation rates per unit mass (i.e., growth efficiency) than intermediate-sized cells in the same population. Sizedependent growth is commonly attributed to transport limitations, such as increased diffusion timescales and decreased
surface-to-volume ratio. However, separating cell size- and cell
cycle-dependent growth is challenging. To address this, we monitored growth efficiency of pseudodiploid mouse lymphocytic leukemia cells during normal proliferation and polyploidization. This
was enabled by the development of large-channel suspended
microchannel resonators that allow us to monitor buoyant mass
of single cells ranging from 40 pg (small pseudodiploid cell) to over
4,000 pg, with a resolution ranging from ∼1% to ∼0.05%. We find
that cell growth efficiency increases, plateaus, and then decreases
as cell cycle proceeds. This growth behavior repeats with every
endomitotic cycle as cells grow into polyploidy. Overall, growth
efficiency changes 33% throughout the cell cycle. In contrast, increasing cell mass by over 100-fold during polyploidization did not
change growth efficiency, indicating exponential growth. Consistently, growth efficiency remained constant when cell cycle was
arrested in G2. Thus, cell cycle is a primary determinant of growth
efficiency. As growth remains exponential over large size scales,
our work finds no evidence for transport limitations that would
decrease growth efficiency