Reduced WNT5A signaling in melanoma cells favors an amoeboid mode of invasion

Abstract

Tumor cells invade and spread via either a mesenchymal or an amoeboid mode of migration. Amoeboid tumor cells have a rounded morphology and pronounced RhoA activity. Here, we investigate how WNT5A signaling, a tumor promotor in melanoma, relates to Rho GTPase activity and amoeboid migration. We compared melanoma cells with low (HTB63 cells) and high (WM852 cells) WNT5A expression. HTB63 cells exhibited an amoeboid morphology and had higher RhoA activity but lower invasiveness than WM852 cells in a three-dimensional (3D) collagen matrix. We next explored the relationships between WNT5A, morphology, and invasive behavior. WNT5A knockdown impaired Rho GTPase Cdc42 activity, resulting in reduced invasion of amoeboid and mesenchymal melanoma cells. Interestingly, knockdown of WNT5A or inhibition of its secretion in WM852 cells expressing wild-type BRAF also led to increased RhoA activity via decreased RND3 expression, resulting in predominantly amoeboid morphology. In contrast, such treatments had the opposite effects on RND3 expression and RhoA activity in HTB63 cells expressing the active BRAF V600 mutation. However, treatment of HTB63 cells with a BRAF inhibitor made them respond to WNT5A knockdown in a similar manner as WM852 cells expressing wild-type BRAF. We next found that dual targeting of WNT5A and RhoA more effectively reduced melanoma cell invasion than targeting either protein individually. Taken together, our results suggest that low WNT5A signaling in melanoma cells promotes a rounded amoeboid type of invasion, which quite likely serves as a compensatory response to decreased WNT5A/Cdc42-driven invasion. This phenomenon partially explains the enduring melanoma cell invasion observed after impaired WNT5A signaling and has therapeutic implications. Our results suggest that dual targeting of WNT5A and RhoA signaling is a more effective strategy for controlling the invasion of BRAF wild-type and BRAF V600 mutated melanomas treated with a BRAF inhibitor than targeting either of the proteins individually.

Structure-based design of CDC42 effector interaction inhibitors for the treatment of cancer

“…While RHOJ and CDC42 have not been found to be mutated in melanoma, they are often overexpressed ( Tucci et al, 2007 ). CDC42 regulates melanoma invasion and is activated in BRAF-resistant melanoma cells ( Gadea et al, 2008 ; Jobe et al, 2021 ; Lu et al, 2017 ). RHOJ regulates chemoresistance, invasion, and tumor angiogenesis in melanoma ( Ho et al, 2012 , 2013 ; Kim et al, 2014 ).…”

Increased MARCKS Activity in BRAF Inhibitor-Resistant Melanoma Cells Is Essential for Their Enhanced Metastatic Behavior Independent of Elevated WNT5A and IL-6 Signaling

“…The phosphorylation and thereby the activation of MARCKS is traditionally considered to be due to PKC activity, although the literature suggests that MARCKS phosphorylation can also be induced via the RhoA/Rho-associated kinase (ROCK) signaling pathway [ 41 , 42 ]. This possibility is of particular interest for the present study since the WNT5A ligand has been demonstrated to activate both PKC and RhoA signaling in human melanoma cells [ 18 , 21 , 43 ]. Regarding PKC, there are nine PKC isozymes encoded by nine specific genes; however, only six have been associated with melanoma pathogenesis [ 44 ].…”

“…Our results revealed that BRAFi-sensitive A375, A375-R1 and A375-R2 melanoma cells exhibited similar expression levels of RhoA ( Figure 7 C). However, when we measured RhoA activity [ 43 ], we found that both A375-R1 and A375-R2 cells exhibited significantly higher RhoA activity levels than their BRAFi-sensitive counterpart ( Figure 7 D).…”

Molecular Insight into Gastric Cancer Invasion—Current Status and Future Directions

“…WNT5A is a glycosylated and lipid-modified secreted protein ligand that triggers mainly the activation of noncanonical WNT signaling pathways. A recent study explored how WNT5A activity relates to the invasion mode of melanoma cells [ 212 ]. Suppressed WNT5A signaling led to a MAT that reduced the Cdc42-modulated invasion.…”

“…Suppressed WNT5A signaling led to a MAT that reduced the Cdc42-modulated invasion. Remarkably, dual targeting of WNT5A and RhoA activity revealed a more efficient approach to inhibiting melanoma cell metastasis compared to the restoration of individual targets alone [ 212 ]. Increasing evidence has indicated that the biological properties of microtubules, an element of the cytoskeleton, and their dynamics are closely correlated with invasion plasticity [ 213 ].…”