Scientists at City of Hope National Medical Center in Duarte have uncovered how immune cells help tumours grow blood vessels, promoting cancer progression.
Study leader Hua Yu says that new results have implicated a role for the protein Stat3 in the induction of tumour angiogenesis by tumour-associated myeloid cells in mice.
Past research had revealed that constitutively activated Stat3 in tumour cells plays a role in promoting tumour angiogenesis.
It was found in the study that Stat3 is also constitutively activated in myeloid cells isolated from mouse tumours, and that these cells could induce angiogenesis in vitro, because the constitutively activated Stat3 induced the cells to produce angiogenic factors.
Further analysis indicated that constitutively activated Stat3 also induced tumour cells and tumour-associated myeloid cells to produce factors that induced endothelial cells to express Stat3, and that this was important for promoting angiogenesis in vitro.
The researchers say that, consistent with the conclusion that constitutive activation of Stat3 in tumour-associated myeloid cells is important for tumour angiogenesis, if the myeloid cells expressed no Stat3 tumour angiogenesis was markedly decreased.