Rogue Cells Cooperate Only to Help Themselves
Among the microbes that cooperated to divide responsibilities, share resources and eventually evolve into the multi-cellular creatures that include humans, there have always been cheaters. And those cellular scoff-laws, many scientists say, may help explain the ancient origins of cancer.
In a New York Times science article, George Johnson explains that cooperating communities within multi-cellular organisms are held together “by a delicate web of biological compromises,” in which each cell surrenders some of its autonomy and contributes to the prosperity of the whole. He says cheaters are individual cells that break loose from the constraints of community, multiply selfishly, hog resources and expand their turf. Johnson cites research suggesting cancer is an inevitable consequence of multi-cellularity. In “Cancer Across the Tree of Life, Cooperating and Cheating in Multicellularity,” in Philosophical Transactions B, researchers at the Institute for Advanced Study in Berlin report finding cancer and cancer-like conditions in nearly all multi-cellular organisms--fungi, plants, insects, birds, reptiles, fish and corals, as well as in mammals.
The Institute researchers say cancer is a breakdown of cellular cooperation. While healthy cells reproduce only enough for maintenance or modest growth, rogue cells proliferate wildly, consuming too much nutrition and space and can poison their environments. While healthy cells differentiate, taking on specialized functions, such as being cells for skin, bones or nerves, rogue cells abandon specialized roles and behave in ways that only benefit themselves and not the whole organism. The Institute researches say “deregulation of differentiation is a fundamental and universal aspect of carcinogenesis.” Further, while aberrant cells are usually eliminated by apoptosis, or cellular suicide, the rogue cancer causing cells don’t die until their host does.
Of course, cooperating microbes are capable of extraordinary collective feats, not all of which are good for humans. A Quanta magazine article by Emily Singer notes, for instance, microbes can cooperate to secrete polymers that enable them to form microfilms that utterly thwart antibiotics. Singer cites research showing that some cooperating cellular communities thrive under specific conditions, such as expanding frontiers. Some researchers, she reports, have begun cautious examinations of whether principles that seem to support cellular cooperation may also apply to human populations.
Cooperation and competition can also change and fluctuate. Johnson writes that once cancer cells gain the upper hand, they too can begin cooperating, to the benefit of a tumor and the peril of the host. They can divide and mutate into new differentiated communities with deadly chemical capacities that feed tumors and colonize in remote parts of the body.
“Through a complex chemical dance, cancer cells can even beguile healthy cells into doing their bidding, acting in ways that promote malignancy,” Johnson writes. “It’s a strategy all too familiar in life: cooperate just enough to gain your competitors’ trust them betray them for your own advantage. In the end, there are no winners. The cancer destroys its own ecosystem and dies with its host.”