Echinomycin as a promising therapeutic agent against KSHV-related malignancies

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of several human cancers, including Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), which preferentially arise in immunocompromised patients while lack of effective therapeutic options. Oncoproteins Myc and hypoxia-inducible factor-1 alpha (HIF1 alpha) have been found closely related to KSHV infection, replication and oncogenesis. However, the strategies of dual targeting these two oncoproteins have never been developed and tested for treatments of KSHV-related malignancies. In the current study, we report that treatment of echinomycin dramatically regresses cell growth both in vitro-cultured KSHV + tumor cells and in vivo KS or PEL xenograft mice models, through simultaneously inhibiting Myc and HIF1 alpha expression. Echinomycin treatment also induces viral lytic gene expression whereas not increasing infectious virions production from KSHV + tumor cells. Our comparative transcriptomic analysis has identified a bunch of new Echinomycin-regulated, Myc- and HIF1 alpha-related genes contributed to KSHV pathogenesis, including KDM4B and Tau, which are required for the survival of KSHV + tumor cells with functional validation. These data together reveal that dual targeting Myc and HIF1 alpha such as using Echinomycin may represent a new and promising option for treatments of these virus-associated malignancies.

Automated summary

This study finds that inhibiting the expression of Myc and HIF1 alpha simultaneously can significantly regress cell growth in KSHV-infected tumor cells, suggesting a potential therapeutic option for KSHV-related malignancies.