Subversion of autophagy by Kaposi's sarcoma-associated herpesvirus impairs oncogene-induced senescence

Area of Science:

• Oncology
• Virology
• Cell Biology

Background:

• Oncogenic stress typically triggers cell cycle arrest via oncogene-induced senescence (OIS).
• Autophagy is a cellular process that can be activated by oncogenic stress.
• Kaposi's sarcoma-associated herpesvirus (KSHV) is known to interfere with autophagy, but its role in Kaposi's sarcoma pathogenesis remains unclear.

Purpose of the Study:

• To investigate how KSHV infection affects OIS and autophagy.
• To elucidate the mechanisms by which KSHV proteins modulate these cellular processes.
• To understand the role of KSHV in facilitating tumor cell proliferation.

Main Methods:

• Analysis of DNA damage responses (DDRs) in KSHV-infected cells.
• Quantification of autophagy levels in infected cells.
• Investigation of the roles of KSHV v-cyclin and v-FLIP proteins in blocking senescence and autophagy.

Main Results:

• KSHV infection induces DDRs characteristic of OIS but results in limited autophagy and failure to senesce.
• The combined action of KSHV v-cyclin and v-FLIP proteins underlies these aberrant cellular responses.
• v-FLIP inhibits v-cyclin-induced autophagy and senescence, dependent on its ATG3-binding domains.

Conclusions:

• KSHV employs a coordinated gene expression strategy to subvert autophagy and block senescence.
• This viral mechanism facilitates the proliferation of KSHV-infected cells, contributing to Kaposi's sarcoma pathogenesis.
• Targeting these viral pathways could offer therapeutic strategies against KSHV-driven cancers.