Abstract
Ras homolog family member A (RhoA) and Rho-associated coiled coil-containing protein kinases 1 and 2 (ROCK1 and 2) are key regulators of focal adhesion, actomyosin contraction and cell motility. RhoA/ROCK signaling has emerged as an attractive target for the development of new cancer therapeutics. Whether RhoA/ROCK is involved in regulating the formation of tumor cell vasculogenic mimicry (VM) is largely unknown. To confirm this hypothesis, we performed in vitro experiments using hepatocellular carcinoma (HCC) cell lines. Firstly, we demonstrated that HCC cells with higher active RhoA/ROCK expression were prone to form VM channels, as compared with RhoA/ROCK low-expressing cells. Furthermore, Y27632 (a specific inhibitor of ROCK) rather than exoenzyme C3 (a specific inhibitor of RhoA) effectively inhibited the formation of tubular network structures in a dose-dependent manner. To elucidate the possible mechanism of ROCK on VM formation, real-time qPCR, western blot and immunofluorescence were used to detect changes of the key VM-related factors, including VE-cadherin, erythropoietin-producing hepatocellular carcinoma-A2 (EphA2), phosphoinositide 3-kinase (PI3K), matrix metalloproteinase (MMP)14, MMP2, MMP9 and laminin 5γ2-chain (LAMC2), and epithelial-mesenchymal-transition (EMT) markers: E-cadherin and Vimentin. The results showed that all the expression profiles were attenuated by blockage of ROCK. In addition, in vitro cell migration and invasion assays showed that Y27632 inhibited the migration and invasion capacity of HCC cell lines in a dose-dependent manner markedly. These data indicate that ROCK is an important mediator in the formation of tumor cell VM, and suggest that ROCK inhibition may prove useful in the treatment of VM in HCC.
Highlights
Vasculogenic mimicry (VM) was first described by Maniotis et al [1] as a new blood supply system independent of endothelial vessels in malignant melanoma
To examine the involvement of Ras homolog family member A (RhoA)/ROCK signaling in VM formation, VM capacity and expression of RhoA, ROCK1 and ROCK2 were investigated in five hepatocellular carcinoma (HCC) cell lines with different metastasis potentials and one hepatocyte cell line
It was found that MHCC97H and Human umbilical vein endothelial cells (HUVEC) had the capacity of VM formation (Figure. 1A)
Summary
Vasculogenic mimicry (VM) was first described by Maniotis et al [1] as a new blood supply system independent of endothelial vessels in malignant melanoma It reflects the plasticity of aggressive tumor cells that express vascular cell markers and line tumor vasculature as has been demonstrated in many malignant tumors including HCC, the third most common cause of cancer mortality worldwide [2,3,4,5]. The RhoA small GTPase and its serine/threonine kinase downstream effector (ROCK1 and 2) control a wide variety of ubiquitous biological processes including the acquisition of unlimited proliferation potential, survival and evasion from apoptosis, tissue invasion differentiation, gene expression, and in particular, regulation of cell detachment, cell movement and establishment of metastasis [6,11]. RhoA/ROCK as a therapeutic target for VM has not been documented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
