Marine microorganisms are a hopeful source of innovative compounds for medical applications. Bacterial anionic polysaccharides from different microorganisms can share some biological properties with glycosaminoglycans. An exopolysaccharide (EPS), recently named infernan and produced by a deep-sea hydrothermal bacterium assigned Alteromonas infernus, presenting a singular structure was investigated. After chemical modifications of infernan EPS, highly oversulfated low-molecular weight derivatives called OSIDs were isolated.[1]

In MAPACA project, OSIDs with different sulfate group contents and molecular weights were produced and evaluated in order to identify a lead for the cancer therapy. Their effect was first assessed in vitro in a large series of human and murine tumor cell lines. OSID4 was the most effective OSID, showing a significant dose-dependent inhibitory effect on the viability of cancer cells. Then, OSID4 was analyzed in immunocompetent tumor-bearing mouse models. Interestingly, OSID4 significantly slowed down progression of lung and melanoma tumor growth. In immunodeficient mice bearing a human lung carcinoma, OSID4 revealed a notable inhibitory effect, comparable to doxorubicin. Toxicity and pharmacokinetic parameters disclosed that OSID4 presented no toxicity and no bleeding risk.[2]

In conclusion, by combining its notable anticancer and moderate anticoagulant activities, OSID4 may be promising for treatment of cancers associated with a high risk of thromboembolic events.

[Acknowledgments: This work was supported by Ifremer and SATT Ouest Valorisation for Engineer funding and financial supports - MAPACA project]

[1] Colliec-Jouault S. et al. Biomacromolecules. 2023, 24, 462-470. doi : 10.1021/acs.biomac.2c01277.

[2] Heymann D. et al. Int J Biol Macromol. 2025, 308(Pt 1),142074. doi: 10.1016/j.ijbiomac.2025.142074.