Prkci activates Jak2/Stat3 signaling to promote tumor angiogenesis

Background

Tumor angiogenesis is essential for colorectal cancer (CRC) progression, providing oxygen and nutrients to sustain tumor growth and metastasis. Protein kinase C iota (Prkci) is an atypical protein kinase known for its oncogenic roles in various cancers; however, its function in CRC angiogenesis remains largely unexplored. This study investigates the role of Prkci in regulating tumor angiogenesis through the Jak2/Stat3 signaling pathway.

Methods

Prkci expression levels in CRC tissues and their correlation with micro-vessel density and patient prognosis were analyzed. Functional experiments, including endothelial cell proliferation, migration, and tube formation assays, were performed in vitro to assess the angiogenic effects of Prkci. In vivo, a CRC xenograft mouse model with Prkci knockout was used to evaluate tumor growth and angiogenesis. Mechanistic studies explored how Prkci activates Jak2 by phosphorylating it at the S633 site, leading to downstream Stat3 activation and Vegfa expression.

Results

Prkci was upregulated in CRC tissues and correlated with increased micro-vessel density and poor patient prognosis. In vitro, Prkci overexpression enhanced endothelial cell proliferation, migration, and tube formation, while Prkci knockout inhibited these processes. Mechanistically, Prkci phosphorylated Jak2 at S633, leading to enhanced Stat3 activation and increased Vegfa expression, which promoted angiogenesis. In vivo, Prkci knockout in CRC cells significantly reduced tumor growth, angiogenesis, and prolonged survival in a mouse model.

Conclusions

These findings identify Prkci as a key regulator of angiogenesis in CRC through Jak2/Stat3 signaling activation. Targeting Prkci could provide a novel therapeutic approach to inhibit tumor angiogenesis and limit CRC progression.