Cast BindingList of interface to filter by dynamic linq query knowing the type

I have a bindinglist of type ISomething. That I need to filter with a dynamic linq query.

BindingList<ISomething> myList;
var myType = typeof(MyClass); (MyClass a class that implements ISomething)

I need to be able to cast to a bindinglist of myClass just by knowing the myType.

var result = myList.Cast<something?>.AsQueryable().Where("FilterOption=\"Filter\"");