The Aurora-A–Twist1 axis promotes highly aggressive phenotypes in pancreatic carcinoma

Abstract

We uncovered a crucial role for the Aurora kinase A (AURKA)-Twist1 axis in promoting epithelial-to-mesenchymal transition (EMT) and chemoresistance in pancreatic cancer. Twist1 is the first EMT-specific target of AURKA that was identified using an innovative screen. AURKA phosphorylates Twist1 at three sites, which results in its multifaceted regulation -AURKA inhibits its ubiquitylation, increases its transcriptional activity and favors its homodimerization. Twist1 reciprocates and prevents AURKA degradation, thereby triggering a feedback loop. Ablation of either AURKA or Twist1 completely inhibits EMT, highlighting both proteins as central players in EMT progression. Phosphorylation-dead Twist1 serves as a dominant-negative and fully reverses the EMT phenotype induced by Twist1, underscoring the crucial role of AURKA-mediated phosphorylation in mediating Twist1-induced malignancy. Likewise, Twist1-overexpressing BxPC3 cells formed large tumors in vivo, whereas expression of phosphorylation-dead Twist1 fully abrogated this effect. Furthermore, immunohistochemical analysis of pancreatic cancer specimens revealed a 3-fold higher level of Twist1 compared to that seen in healthy normal tissues. This is the first study that links Twist1 in a feedback loop with its activating kinase, which indicates that concurrent inhibition of AURKA and Twist1 will be synergistic in inhibiting pancreatic tumorigenesis and metastasis.

Insights into the non-mitotic functions of Aurora kinase A: more than just cell division

“…Again, it would be interesting to explore whether these events require the prior activation of AURKA on AURKA was also shown to play an active role in the Epithelial-Mesenchimal transition (EMT) in oestrogen receptor -positive breast cancer models [119], and in models of pancreatic cancer [120,121].…”

“…However, the molecular mechanism by which AURKA induces EMT remains to be fully disclosed. Two parallel studies identified two direct substrates of AURKA implicated in pancreatic EMT programs, aldehyde dehydrogenase 1 (ALDH1A1) [120] and Twist-related protein 1 (TWIST1) [121]. The AURKA-dependent phosphorylation of both proteins increases their respective enzymatic activity, with a dramatic enhancement of cell motility, drug resistance and the acquisition of a stem-like phenotype.…”

TWIST1 homodimers and heterodimers orchestrate lineage-specific differentiation

“…Hypo-phosphorylation mutations (T121A, S123A) near or at the Helix I phosphorylation sites was previously shown to favour homodimerization (Firulli et al, 2005). Yet a triple phospho-mutant model of TWIST1 (S123A, T148A and A184A) in oncogenic cell lines showed preference for dimerization with TCF3 and HAND2 compared to wildtype TWIST1 (Wang et al, 2017). In line with this, we find that two individual hypo-phosphorylation mutants (R118H, S123A) both increased preference for TCF12 heterodimer formation, whilst phospho-mimetic forms at T121 and S123 reduced heterodimerization, compared to wildtype TWIST1.…”

The significant others: Global search for direct kinase substrates using chemical approaches

“…We have identified many substrates of Cdk5‐as1/p25 in mouse brain lysates, which uncovered several molecular mechanisms by which deregulated Cdk5 promotes neurodegenerative pathways in Alzheimer's disease pathogenesis . Similarly, this approach revealed oncogenic targets of Aurora A kinase in breast and pancreatic cancer, which unraveled the mechanism of Aurora A‐induced epithelial to mesenchymal transition and cancer stem cell formation in highly aggressive cancers . As such, the ASKA method represents a powerful tool for identifying kinase‐specific substrates.…”

“…Despite two mutations in the active site, both Aurora A‐as7 and Aurora B‐as7 are highly active in cells and in vitro; and show very high catalytic efficiency with N‐6‐phenethyl ATP analog. Using Aurora A‐as7 kinase, we have identified several direct targets including PHLDA1, LIMK2, ALDH1A1, and TWIST1 in cell lysates .…”