Can We Make Metastatic Prostate Cancer Cells Fragile Again?

Metastasis requires more than the ability to grow. Tumor cells that enter the bloodstream must also survive powerful mechanical forces that can physically damage or destroy them. A new preclinical study suggests that prostate cancer cells can adapt to this stress, and identifies CALB2 as a possible weak point in that adaptation.
Researchers repeatedly exposed prostate cancer cells to high fluid shear stress, effectively selecting cells able to survive conditions similar to those encountered in circulation. PC3 cells, derived from a bone metastasis, were already more resistant than LNCaP cells and became even more resistant after repeated mechanical selection.
The adapted cells also behaved more aggressively in vivo. Molecular analysis showed that CALB2, which encodes the calcium-binding protein calretinin, was strongly increased in the shear-resistant PC3 cells.
The most important experiment came when researchers used CRISPR to knock out CALB2. After renewed shear stress, survival of the mechanically adapted cells fell to about 35.6%, compared with roughly 77–79% in control cells. In other words, removing CALB2 appeared to strip away much of the protection the cells had acquired against mechanical damage.

This raises an unusual therapeutic possibility: instead of attacking tumour growth directly, future treatments might make circulating cancer cells less able to survive the physical journey required for metastasis. CALB2 is far from being a validated drug target, and the work remains preclinical, but the concept is intriguing because it targets a vulnerability linked specifically to metastatic dissemination rather than proliferation alone.

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