The protein IMP2 (insulin-like growth factor 2, mRNA-binding protein 2) plays a crucial role in promoting tumor growth in tumor-associated macrophages. Researchers led by Professor Alexandra K. Kiemer from Saarland University were able to show in cell culture models that macrophages in the tumor environment that produce IMP2 accelerate the growth of cancer cells. If IMP2 is missing in these immune cells, the tumor grows much more slowly.

Macrophages – the scavenger cells of the immune system – can be reversed in the tumor microenvironment and support cancer growth instead of fighting it. Previous work by the team had already shown that tumor cells recruit macrophages with the help of IMP2 and reprogram them into tumor-promoting cells. In the current study, the scientists specifically focused on IMP2 in the macrophages themselves.

In experiments with co-cultured cancer cells and macrophages, tumors grew significantly faster when the macrophages expressed IMP2. If the protein was missing in the macrophages, tumor growth slowed down significantly – due to this genetic intervention alone. The researchers suspect that IMP2 increases the motility of macrophages and makes it easier for them to penetrate the tumor.

A key mechanism lies in lipid metabolism: macrophages with IMP2 showed a change in the lipid composition of their cell membranes, which became more fluid and thus more mobile – comparable to oil instead of solid butter. This increased membrane fluidity could help the macrophages move more quickly through the tissue and actively support the tumor.

IMP2 is relevant in the tumor environment not only in the cancer cells themselves, but also in the surrounding immune cells, explained Alexandra K. Kiemer, Professor of Pharmaceutical Biology. The protein creates a tumor-friendly microenvironment by mobilizing macrophages and enhancing their tumor-promoting properties.

The results, which have been published in the “International Journal of Biological Sciences”, open up new therapeutic approaches in the long term: Targeted inhibition of IMP2 in tumor-associated macrophages could slow down tumor growth without severely impairing the normal immune defense.

At the same time, another study in the same research environment (International Journal of Cancer, DOI: 10.1002/ijc.70340) confirmed the role of IMP2 in other cell types of the tumor microenvironment. There, too, the protein influences central processes such as metabolism and cell motility in the interaction between tumor and immune cells.

Original Paper:

IGF2BP2 Deficiency in Macrophages Impairs Migration, Reprograms Metabolism, and Limits Tumor Progression

Editor: X-Press Journalistenbüro GbR

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