FIG 2.

ASS1 is essential for KSHV-induced cell proliferation and cellular transformation. (A and B) Analysis of ASS1 expression in MM and KMM cells following depletion of ASS1 expression by RT-qPCR (A) and Western blotting (B). (C and D) ASS1 knockdown inhibits cell proliferation and cellular transformation of KMM cells. Cell proliferation (C) and colony formation in soft agar (D) were examined following knockdown of ASS1 with 3 shRNAs (sh1, sh2, or sh3) or a scrambled shRNA (control [ctl]). Representative pictures at a ×40 magnification from soft agar assays are shown (D, left). Colonies with diameters of >50 μm were counted, and the relative number of colonies per field was quantified (D, right). (E and F) ASS1 knockdown induces cell cycle arrest and apoptosis. (E) The cell cycle was analyzed by flow cytometry 48 h following transduction with ASS1 shRNAs (shASS1). (F) Apoptotic cells were detected by annexin V staining 72 h following transduction with ASS1 shRNAs. *, **, and *** represent P values of <0.05, <0.01, and <0.001, respectively, while NS indicates “not significant.”