The Ecology of Cancer, and What do Ants have to do with it?

Ants are like cancer cells. Conversely we might say that cancer cells are like ants.

Even though they sometimes feel more mammoth-like and slothful, lumberingly prehistoric rather than tiny and socially frenzied. “They feel.” Of course cancer cells do not have feelings so far as I know. What I mean is that they feel to me, these colonies of CLL cells that circulate through the bone marrow and the blood and the lymphatic system, they feel to me massive and heavy and slow. Or more accurately, they make me feel like a sloth, I imagine myself as one of those creatures I saw a few weeks ago in the Tar Pits in Los Angeles: slowly dragging my massive body over the never-ending earth. But in the last few weeks I have also been having nightmares, dark and jagged dreams in which a massive sloth-like creature is out there, lumbering over the horizon, coming closer, filling the screen, threatening to engulf me. This CLL beast exists, I guess, both within and without.

When I heard Deborah Gordon declare that ants are like cancer colonies I experienced a rush of resistance. I did not welcome the idea of analogizing my condition to a common-and-garden insect that lives in colonies, rather than to the singularity of an exotic species of mega fauna now extinct. I was alarmed not charmed by the image of colonies of ants scurrying around in my body. But also in some peculiar way I did not yet quite understand, this analogy—of cancer cells to an ant colony—struck a chord. Suddenly a new image, one not immediately accessible to my habits of thinking and feeling, began to reverberate.

Ants, the ants that I know, live in my garden, not in my body. It has always been mysterious to me the way ant colonies would spring up in the garden, how they would know where the aphids were congregated, how they would march and scurry from their nests to my favorite rose bush, devastated by a colony of aphids. Aphids are small insects that suck the life out of plants and then secrete a sugar-rich sticky honeydew that ants love. In fact they “farm” the aphids, protect them from predators and parasites and nurture their eggs. In the face of this alliance—a mutualistic relationship or type of symbiosis—I would feel very small and ineffectual. All I could do would be to hope for an invasion of ladybugs (to eat the aphids, and thus deflect the ants) or I could spend hours everyday hosing off the aphids with jets of water. Sometimes you would sink a pitch fork into the compost pile and as if from nowhere a black mass of moving matter would crawl up your arm. After initial panic—rushing around dementedly shaking arms, trying in a frenzied manner to brush the ants off—I figured out that in the process of pursuing their own ends, foraging for fabulous stuff to take back to their nests, they were doing me a favor. Like worms, they were doing their bit to toss and turn and hasten the process of decomposition in the compost. In the end by leaving things be—as much as is possible for a neurotic controlling gardener—the garden settled into its own ecology. Or rather, it became more possible to observe the interaction of plants and creatures. To see, for instance, which plants attracted bees and when. African blue basil and rosemary are bee magnets. The weedy fennel, when it’s younger is a host for the swallow tail caterpillar that turns into a spectacular butterfly, flits around the garden and then sashays off to Mexico. Later, when the garden is festooned with the fennel’s yellow umbels the bees come swarming in.

But the story is not so simple, not such a paean to natural balance and harmony.

Enter the chickens.

Nowadays there are no infestations of ants, no plagues in the garden. The beak of a chicken and a squirrely squirming ant—these things exist together in a powerful force field of attraction. Heaven if you are a chicken, pretty dismal, I guess, if you are an ant. Though maybe the ants have just changed their habits, become invisible to chicken and human eyes, or moved on over to my neighbor Mrs Tam’s garden. Chickens also love worms, but since the birds are surface scratchers and since the vegetable beds and the compost are barricaded the worms survive there, in fact they survive everywhere deep in the soil, doing their work, sifting and turning.

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Ants are like cancer cells, says Deborah Gordon, in so far as they are regulated but without central control.

An ant colony is regulated, its survival depends on the distribution and co-ordination of tasks and roles. Communication, or an exchange of cues, exists between the ants. The tasks and roles themselves are not fixed, but shift and change as the environment shifts and shapes. The ants exist in a dynamical social network. A hub may form for instance simply by ants moving into a space where there are lots of interactions. Gordon calls it the anternet. Ants do not always behave the same way. Foraging behavior for instance changes in times of drought. If one element changes (e.g. the availability of water) then the behavior of the colony changes. These changes, in turn, shape social and reproductive patterns. By observing these changes in patterns of behavior or modes of regulation, scientists can observe how natural selection is working on this colony.

There are many biological systems, apart from ants, that function without hierarchy. Bird flocks, without a leader, turn in the sky, fish schools swerve to avoid predators, tropical forests develop patterns of diversity… and cancer cells mutate and metastasize. For all of these systems, we still don’t fully understand how the parts work together to produce the dynamics, the history, and the development of the whole system.

It has often felt to me as though the garden is a battlefield. The march to the rose bushes and the swarming in the compost bin seem to be ant maneuvers carried out with all the efficiency of military campaigns, masterminded by some center of control (and sometimes the body too feels like and is popularly conceived of as a battle zone where the war against cancer is waged). Indeed this is how the great and pioneering ant scholar E.O. Wilson described ant society—in terms of hierarchy, conflict and regimental organization. So why should we relinquish this view (or feeling) in favor of the model proposed by younger scientists, including Deborah Gordon? Most significant for me, in terms of the efficacy of the analogy, is that Gordon and others tell a different sort of system story, emphasizing situated (therefore variable) processes of recognition and response. They understand the ant colony as composed of flexible units (whose functions change according to situation) and propose a system characterized by different architecture and components. Nodes of interaction are at the heart of Gordon’s model and frequencies of interactions at nodes are what shape material social orders. It is this that grounds the argument against the way that Wilson’s analogy works, wherein the behavior of ants is offered as a sociobiological model for human behavior. Ants, Gordon argues, don’t provide moral lessons or insight into behavior or feelings, but they do provide insight about the dynamics of networks, systems without central control.

It’s a tricky business, this maneuvering (is it a dance or a battle?) between feelings and conceptual models, between the garden and the body, ants and cancer cells. Sometimes new images, just as much as new data, can interfere with feelings and reorient one’s thinking.

What matters in networks is the ecology of the system.

So, taking our cue from ant colonies, how might we think about the ecology of cancer? What are some of the ways that cancers diversify and spread? How is organization regulated? How, with answers to some of these questions, might we approach intervention in ways less dramatically belligerent?

Cells in the body act collectively—for example, as networks of neurons to produce sensations, or as patrolling T-cells that mobilize other immune cells to respond to pathogens. It seems they communicate with one another. In the process of metastasis, the cancer cells may use signals from healthy tissue to recruit other cancer cells to a new location, where certain areas of tissue constitute an attractive resource. If researchers can figure out how cancer cells are recruiting then maybe they can set traps to prevent them from doing this.

All very well, but it doesn’t solve my problem (and my oncologist’s) which is how to understand the malignant cells of my cancer, Chronic Lymphocytic Leukemia (CLL), as part of a cancerous system, given that it is a cancer of the blood not manifested in solid tumors. In CLL the cancer cells (malignant B cells, a type of white blood cell) course through the marrow and travel through the blood and lymphatic system. What happens in a “normal” body is that the B cells are recruited to fight infection, they die off often and regularly and new ones grow. In CLL, because of some genetic glitch, they don’t die off but in fact relentlessly proliferate, interfering with and crowding out the production of healthy white cells, red cells and platelets.

Although the cancer is in the blood and not localized in tumors the cells do cluster, they form hubs just like ants. They cluster in lymphoid tissue. Research has identified a form of regulation in this lymphoid tissue, or micro-environment, whereby malignant B cells communicate with other healthy cells. Curious about the relation of the cancer cells to certain healthy cells Dr Kipps and his colleagues looked at this relationship in the lab. They found that when the CLL cells were removed from the “suspicious” healthy cells, the CLL B cells began to die, whereas the same cells, when replated back onto the healthy cells, perked up immediately. Because they supported the survival of CLL cells and because CLL B cells became attached to them, the researcher group called them “nurse-like cells,” or NLC. They concluded that one of the ways CLL cells survive is by recruiting these protector cells.

Dr K describes CLL as a very social beast. By this he means that the survival of the cells depends upon a network of relations, which indeed amounts to a form of regulation, without central control. The relation between the NLC and the CLL B-cells is symbiotic just like that between ants and aphids. In a dynamical system like an ant colony it is possible to observe how when one element changes (e.g. the introduction of drought) the behavior of the colony changes. So, similarly, by focusing on the microenvironment of another dynamical system – a colony of cancer cells – it becomes possible to envisage forms of intervention more akin to the strategic introduction of drought, rather than war. Rather than therapies which are the equivalent of carpet bombing, indiscriminately destroying good blood cells along with the bad (which anyway doesn’t work with CLL which is notably resistant to standard chemotherapy), the solution might be to try and intervene in the signaling system to change the behavior of the cancer colony. Or, as Dr K puts it: to foster therapies that isolate the CLL cells so that they die of social neglect.

To observe how cancer colonies evolve, how cellular activity is regulated, how selections are made: this chimes with other ideas vibrating in the air in this second decade of the twenty first century when the Darwinian inheritance is being reconfigured. We humans have made such a mess of the planet that perhaps our only hope lies in attending more closely to other forms of organization, to looking more closely at ants and fungi and chickens (with whom we share about 60% DNA) and extinct species like the sloth from the Paleolithic era to species like bees that are disappearing by the day, as we poison the environment and our own bodies. By looking outside the human body to other “bodies” or clusters of living cells in the natural world it seems to me that we have more chance of figuring out solutions, or ways of being in the world, perhaps even ways of living with cancer rather than definitively conquering it. Just as in certain approaches to invasive species in habitat studies. It’s a reversal of the gaze or perspective. Rather than trying to understand the natural world through the lens of human society, we reverse the perspective so that a description of a natural society—an ant colony in this instance—can illuminate how we think about modes of organization in the human body. Or, more pertinently (since reversals always carry the dangers of dualism) we can begin to think of the nature-society play as itself like an ant colony.

I don’t for a moment think that Dr K and co are spending their time out in the desert down on their knees observing the behavior of ants. They are in the laboratory working late at night, separating the malignant B-cells from their nurse-like protectors and replating them, and trying to figure out how to intercept the signals. They are running algorithms. In defining the various cells, structures and molecules that protect the CLL cells they are working on the development of novel anti-leukemia agents such as monoclonal antibodies and immune-based treatment strategies and genetically engineered T-cells. No, they are not looking at ants; but for me, as a gardener and a non-scientist and someone with cancer, bells start chiming.

In writing this I have become less alarmed by the ant analogy, more attuned to the reverberations sparked by hearing Deborah Gordon speak. At some point analogy clicks and opens up a different link. A link to the ecological.

Even though he places emphasis on the environment Dr K is cautious: We still don’t fully understand how the parts work together to produce the dynamics, the history, and the development of the system, he says. There isn’t a single explanation for how CLL happens, let alone how it evolves, adapts, transforms. Unpredictable things happen. Needless to say there also isn’t a single solution.

Nevertheless, this perspective gives me hope. Not that a cure for CLL will be produced tomorrow, but certainly that more efficacious and less damaging possibilities are opening up that might prolong the life expectancy of people with CLL (so far this has not been possible). The outlook is considerably brighter than when I was first diagnosed six years ago.

It fills me with energy and hope: that this research can be understood in terms of a larger project, within an ecological matrix encompassing micro and macro environments, time scales ranging from the big bang to now, symbiotic relations as apparently diverse as the relation between ants and aphids in a garden and malignant B-cells and nurse-like cells in a CLL environment.

It gives hope when things are going well (like now, when treatment is resting in a sweet spot). Not when you are teetering on the edge of a chasm filled with black rising sludge and you see death edging its way up out of the tar pits toward you, like a massive land sloth.

In the dark times it is the sloth that imaginatively materializes, rather than a colony of ants. Although the ant analogy has greater scientific resonance, the sloth connects affectively to my bodily experience. But in the process of writing this piece I have relinquished the idea of ants scurrying around inside my body, am more able to situate ants and cancer cells in an analogous relation, within the framework of dynamical systems. This I realize: it is not necessary to feel ant-like in order to grasp the import of the analogy. You might say my cognitive apprehension has marginally improved. On the other hand, it is only through sensation, through ways that the body experiences being in the world, being in the garden as well as in the hospital and the lab, that understanding grows. Figures of speech, often fantastical, may seem to be at odds with scientific data, but the human sensorium involves a rich patterning of signaling networks. The connections between science and imagination are myriad and marvelous.

 

Notes

“Ants are like cancer cells”…….. Deborah Gordon in her talk “The evolution of collective behavior in ant colonies.” at the conference, “Anthropocene: Arts of living on a damaged planet,” May 8-10, 2014, organized by Anna Tsing at the University of California, Santa Cruz. Her writings include Ant Encounters: Interaction Networks and Colony Behavior (Primers in Complex Systems) and Ants At Work: How An Insect Society Is Organized.

“the researcher group called them “nurse-like cells,” or NLC”….. “Blood-derived nurse-like cells protect chronic lymphocytic leukemia B cells from spontaneous apoptosis through stromal cell–derived factor-1”

Jan A. Burger, Nobuhiro Tsukada, Meike Burger, Nathan J. Zvaifler, Marie Dell’Aquila, Thomas J. Kipps,  Blood. Oct 2000,96(8)2655-2663; http://bloodjournal.org/content/96/8/2655?variant=long

“chickens (with whom we share about 60% DNA)”….. NIH 2004 News Release. “Researchers Compare Chicken, Human Genomes: Analysis of First Avian Genome Uncovers Differences Between Birds and Mammals” National Human Genome Research Institute. Last Updated: November 17, 2011http://www.genome.gov/12514316.  Accessed May 15, 2014.

 

 

One thought on “The Ecology of Cancer, and What do Ants have to do with it?

  1. Lesley,
    May your every day in Mexico be magic.
    And healthy. I get the gist of this post enough to be infected by your hopefulness. The ants made me think of the Pink Robots. All the analogies–these complex attempts to understand–seem helpful. Eagerly awaiting posts about your travels.
    And sending love

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