This paper describes use of D17-c3 cells. As the authors point out, a relatively small number of cell types are typical for RNAi screens but a large number of others are available from the DGRC.
Currie & Rogers (2011) Using the Drosophila melanogaster D17-c3 cell culture system to study cell motility. Nat Protoc 6(10):1632-41. PubMed ID: 21959242