PKN3

PKN3 (protein kinase N3) is a serine/threonine kinase of the AGC kinase family and a member of the PKN isoform group that functions downstream of phosphoinositide 3-kinase (PI3K) signaling to regulate malignant cell growth and invasive behavior^[1]. Mechanistically, PKN3 is regulated by PI3K at both the expression and catalytic activity levels and contributes to invasive growth in prostate cancer models, linking PI3K/PTEN pathway activation to tumor progression^[1]. PKN3 also interacts with Rho-family GTPases and shows preferential association with RhoC, a regulator of tumor invasion and metastasis, providing a mechanistic connection between cytoskeletal remodeling, cell motility, and metastatic dissemination^[2]. In orthotopic tumor models, suppression of PKN3 inhibits primary tumor growth and metastasis, supporting its functional importance in cancer progression^[1][2]. Disease relevance is further supported by genetic and pharmacological studies indicating that PKN3 participates in angiogenesis and metastatic processes and is frequently investigated in prostate, breast, and other advanced malignancy models^[2][3]. Compared with related isoforms, PKN family members are structurally similar but functionally distinct; PKN1 and PKN2 perform nonredundant biological roles, whereas PKN3 is particularly associated with PI3K-dependent malignant growth and RhoC-linked metastatic phenotypes^[2][4]. For experimental applications, PKN3 has been targeted using RNA interference approaches, including the liposomal siRNA formulation Atu027, which demonstrated inhibition of cancer progression in preclinical models and established PKN3 as a tractable research target for pathway interrogation and therapeutic development^[3].