PLA2R1 promotes DNA damage and inhibits spontaneous tumor formation during aging

Area of Science:

• Gerontology and Cancer Biology
• Molecular Mechanisms of Aging and Cancer

Background:

• Aging is a primary risk factor for cancer, yet its molecular underpinnings remain understudied.
• The transmembrane protein Phospholipase A2 Receptor 1 (PLA2R1) is known to promote cellular senescence, a process that can suppress tumor initiation.

Purpose of the Study:

• To investigate the role and mechanisms of PLA2R1 in aging-related cancer development.
• To elucidate how PLA2R1 influences DNA damage repair and senescence in the context of aging.

Main Methods:

• Utilized aged Pla2r1 knockout mice to assess spontaneous tumor development.
• Analyzed Poly (ADP-ribose) polymerase 1 (PARP1) expression and DNA damage levels in knockout and wild-type mice.
• Investigated PLA2R1's effects on human cells, including PARP1 expression, DNA damage, senescence, and the involvement of reactive oxygen species (ROS) and the Retinoblastoma (Rb) protein.

Main Results:

• Old Pla2r1 knockout mice exhibited a higher incidence of diverse spontaneous tumors compared to controls.
• These mice showed elevated PARP1 levels and reduced DNA damage, consistent with human data.
• PLA2R1 expression in human cells decreased PARP1, induced DNA damage and senescence, a process dependent on ROS and Rb, and reversible by PARP1.

Conclusions:

• PLA2R1 acts as a tumor suppressor in aging by downregulating PARP1 through a ROS-Rb pathway.
• This mechanism leads to increased DNA damage and subsequent tumor-suppressive senescence, counteracting aging-associated tumorigenesis.