This immortal creature is capable of creating a type of contagious cancer: ScienceAlert

Jellyfish-like organisms called hydras can develop tumors if they overfeed, which can in turn be passed on to their cloned offspring.

A new study into this strange phenomenon not only reveals details about the process in hydra, but also improves our understanding of transmissible forms of cancer Anyway.

While tumors are an inevitable threat to multicellular organisms, fortunately there are few examples of cancer that can be transmitted between individuals. The most common are: Two influences on the Tasmanian Devilanother example Affects dogs, 11 were observed in shellfish.

Naturally, we are keen to understand how the contagious cancer came about in the first place; that is, to avoid somehow invoking it in our own species, but also in the hope of protecting other creatures from the terrible suffering that Tasmanian devils face due to facial tumour disease.

But all of these known cases of transmissible cancer were well established by the time we discovered this, so evolutionary ecologist Sophie Tissot of French National Centre for Scientific Research (CNRS) and its team We had to take a different approach to tracing the origins of infectious cancers.

It is fitting that a freshwater creature related to jellyfish and sea anemones spontaneously developed tumors in Lab experience 15 years ago In response to overfeeding.

Hydra Oligactus, A freshwater creature, related to jellyfish and sea anemones, considered “immortal” in many ways. It reproduces asexually, cloning itself by forming small buds that break off to grow into a physically separate but genetically identical creature.

This, combined with its tendency to form tumors under laboratory conditions, shows the potential for research into the genes responsible for cancer development. Teso and colleagues set out to show how valuable this model is for understanding the development of transmissible cancers.

“Use Hydra Oligactus“Which shows spontaneous tumor progression that in some strains has become vertically transmissible, this study provides the first experimental observation of the development of a transmissible tumor,” the authors say. He writes.

“Thus, this work constitutes the first contribution to understanding the conditions under which infectious cancer occurs and its short-term consequences for the host.”

They collected 50 hydras from Lake Montaud in France, and brought them back to life in the lab.

To ensure a high rate of tumor development, budding, and thus increased chances of tumor metastasis, the researchers fed some of these polyps an excess of brine shrimp larvae five times a week, mimicking the conditions that drive tumor development in Previous study.

Nineteen of these hypertrophic hydras, which were swollen with tumors after two months, were selected, their shoots collected, and grown in the same conditions. The researchers followed this process through five “generations” of tumor-forming clones, selecting these shoots from their non-tumor-affected counterparts to produce the next generation.

To confirm that the tumors were passed down from parents and not just spontaneously arising each generation, the researchers looked at the descendants of the cancer-free hydra. Hydra from parents who had tumors were four times more likely to have them than those from parents who did not have tumors, even though all the hydra were genetically identical.

Through all this, the researchers confirmed that tumors can indeed be caused in H. Oligactus, The transfer rate can increase over time.

They also observed that the fifth generation of tumor-bearing Hydra began to exhibit changes in their life cycle characteristics compared to their tumor-free counterparts. They increased their investment in asexual reproduction efforts before the tumor had a chance to develop, while slowing down the budding process after the tumors appeared.

This seems to go hand in hand with another change, where the mortality rate of buds was higher after the appearance of tumors.

“T“These modifications suggest that host life cycle traits are modified to compensate for tumor costs by producing more buds when they are more likely to survive and remain tumor-free,” Tissot and colleagues say. He writes.

They suggest that the rarity of transmissible cancers may be due more to the lack of environmental conditions suitable for their spread, as acquiring the ability to metastasize does not appear to have been a problem for cancer cells, at least in this study.

If this is true, then they conclude“,”It is important to take these aspects into account when studying ecosystems disturbed by human activities, as they may modify conditions that favor the spread of infectious cancers.

This research was published in Proceedings of the Royal Society B.