Propagermanium

The formation of premetastatic niches creates a fertile environment for the seeding of disseminated cancer cells in selected secondary organs. This is crucial for the development of metastasis in various malignancies, including breast cancer (BC). We previously reported that the loss of FBXW7 in bone marrow‐derived stromal cells promoted cancer metastasis by increasing the production of the chemokine CCL2, which attracts myeloid‐derived suppressor cells and macrophages to the premetastatic niche. Furthermore, treatment with the CCL2 inhibitor propagermanium (PG), which has been used in Japan as a therapeutic agent against chronic hepatitis B, was shown to block the enhancement of metastasis in FBXW7‐deficient mice through inhibiting the formation of premetastatic niches. Here, we describe a phase I dose‐escalation study of PG used as an antimetastatic drug for perioperative patients with primary BC. The primary end‐point was the percentage of patients who experience dose‐limiting toxicity. Twelve patients were enrolled in the study. Dose‐limiting toxicity was not observed, and the maximum dose was determined to be 90 mg/body/day. The serum concentrations of PG were nearly within the normal range in all observation days. We observed an inverse correlation between FBXW7 mRNA levels in blood and the serum concentrations of CCL2 and interleukin (IL)‐6, in agreement with our previous mouse model. Also, IL‐6 was downregulated in a PG dose‐dependent manner, as observed in mice. Thus, PG was given safely and it is expected to have antimetastatic potential in BC. This trial is registered in the UMIN Clinical Trials Registry as UMIN000022494.

Intracerebral hemorrhage (ICH) remains a devastating type of stroke that lacks an effective treatment. Recent evidence has demonstrated that CCL2 is involved in the blood‐brain barrier (BBB) disruption and propagermanium (PG) as a CCL2 receptor inhibitor is neuroprotective in ischemic stroke. However, whether PG therapy exert effective role in acute ICH still unclear. In this study, our goal was to investigate the potential role of CCL2 and the effects of PG in ICH. Differentially expressed RNAs including CCL2 were detected in human ICH. CCL2 and the activation of p‐p38 MAPK and AQP4 expression were analyzed in rats after ICH. Brain water content and BBB integrity as well as neurological function were also examined after PG administration. In addition, the mechanism by which CCL2‐mediated BBB injury was further investigated by cell coculture. Our findings showed that PG could effectively reduce brain edema and improve neurobehavioral functions. p‐p38 MAPK and AQP4 expression were significantly inhibited by PG in vivo and in vitro. To the best of our knowledge, this is the first demonstration of PG in neuroprotecting the BBB integrity by inhibition of CCL2‐CCR2‐p38 MAPK pathway following ICH, targeting CCL2 could be developed as a novel treatment for hemorrhagic stroke.