Project description:The molecular nature of malignant tumors is well studied in vertebrates, while their evolutionary origin remains unknown. In particular, there is no evidence for naturally occurring malignant tumors in pre-bilaterian animals, such as sponges and cnidarians. This is somewhat surprising given that recent computational studies have predicted that all metazoans are prone to develop tumors. Here we provide first evidence for naturally occurring tumors in Hydra oligactis. Histological, cellular and molecular data reveal that these tumors are transplantable and caused by differentiation arrest of female gametes. Growth of tumor cells is independent from the cellular environment. Tumor bearing polyps have significantly reduced fitness. In addition, Hydra tumors show a greatly altered transcriptome that mimics expression shifts in vertebrate cancers. Therefore, this study shows, that invasive tumors have deep roots in animal phylogeny, and that early branching animals may be informative in revealing the fundamental mechanisms of tumorigenesis. We compared four samples of Hydra oligactis tumor-bearing animals to three samples of female polyps undergoing oogenesis and six samples of female asexual control polyps

2014-06-24 | E-GEOD-56287 | biostudies-arrayexpress

Wnt signaling restores evolutionary loss of regenerative potential in Hydra

Project description:The regenerative potential of animals varies widely, even among closely-related species. In a comparative study of regeneration across the Hydra genus, we found that while most species exhibit robust whole-body regeneration, Hydra oligactis and other members of the Oligactis clade consistently fail to regenerate their feet. To investigate the mechanisms underlying this deficiency, we analyzed transcriptional responses during head and foot regeneration in H. oligactis. Our analysis revealed that the general injury response in H. oligactis lacks activation of Wnt signaling, a pathway essential for Hydra vulgaris foot regeneration. Notably, transient treatment with a Wnt agonist in H. oligactis triggered a foot-specific transcriptional program, successfully rescuing foot regeneration. Our transcriptional profiling also revealed dlx2 as a likely high-level regulator of foot regeneration, dependent on Wnt signaling activation. Our study establishes a comparative framework for understanding the molecular basis of regeneration and its evolutionary loss in closely-related species.

2026-04-25 | GSE295690 | GEO

Eukaryota Opisthokonta Metazoa Eumetazoa Cnidaria Hydrozoa Hydroidolina Anthoathecata Aplanulata Hydridae Hydra Hydra oligactis

Project description:Bacteriome associated with tumors in Hydra oligactis

| PRJNA1203403 | ENA