In the 1977 story conferences excerpted in The Making of ESB, Lucas told Leigh Brackett that, because Lando Kadar was a clone, Leia ought to be suspicious of him, due to the Clone Wars. He further stated that the clones were "partly responsible for the war" and that "on these planets of clones, there are many countries, say about 700 countries and [Lando is] from one of the ruling clone clans."

The rest of the conclusion is my own inference; but it's not a great leap, really, when Lucas's various drafts and outlines from ANH and ESB have multiple dialogue lines lifted verbatim from Dune and its sequels.

Dune was clearly on his mind from the get-go as an influence, back to the very first "Journal of the Whills" outline--where "Prince Luke Skywalker" is the endangered heir of the royal family of a desert planet. In other words, an ersatz Paul Atreides. This role became the character of Princess Leia Aquilae by the time of the rough draft script, under the influence of The Hidden Fortress.