LAUSR

Kaposi's sarcoma (KS) is the second most common tumor in people infected with human immunodeficiency virus worldwide, but its pathogenesis is still unclear. In this study, we discovered that the expression of GATA‐binding protein 3 (GATA3) was lowly expressed in KS tissues and KSHV‐infected cells, while microRNA‐155 (miR‐155) was highly expressed in KS serum and KSHV‐infected cells. miR‐155 promoted the proliferation, migration and invasion of KSHV infection by targeting GATA3. Further, The KSHV‐encoded protein, the Latency associated nuclear antigen (LANA), promotes the proliferation, migration and invasion of KSHV‐infected cells by regulating the miR‐155/GATA3 axis. Regarding the molecular mechanism, c‐Jun and c‐Fos interact to form a complex. LANA upregulates the expression of c‐Jun and c‐Fos and enhances the formation of c‐Jun/c‐Fos complex. The complex binds to the −95∼−100 bp site of miR‐155 promoter and transcriptionally activates miR‐155. All in all, LANA enhances the c‐Jun/c‐Fos interaction, resulting in enhanced transcriptional regulation of miR‐155 by the c‐Jun/c‐Fos complex, thereby downregulating GATA3 and promoting the proliferation, migration and invasion of KSHV‐infected cells. The discovery of LANA/c‐Jun/c‐Fos/miR‐155/GATA3 further refines the pathogenesis of KS, potentially opening a new avenue for developing effective drugs against KS.