Yes, it is possible to use the PanelBar control in a Prism-based application. The only thing that may be specific to the PanelBar is that you may want to provide some custom styling for the second-level items that will wrap the content that will be injected in your regions. Other than that, it should be as simple as this:
<ContentControl prism:RegionManager.RegionName="InboxRegion" />
You could also go for an alternative approach and bind the PanelBar's ItemsSource to a collection of ContentControls or ItemsControls depending on your requirements. With the alternative you will avoid hard coding the PanelBar items in XAML - this will be useful if the number of regions you want to define is determined at runtime.
All the best,
the Telerik team