MK3 Modulation Affects BMI1-Dependent and Independent Cell Cycle Check-Points

Peggy Prickaerts, Hanneke E. C. Niessen, Vivian E. H. Dahlmans, Frank Spaapen, Juliette Salvaing, Jolien Vanhove, Claudia Geijselaers, Stefanie J. J. Bartels, Iris Partouns, Dietbert Neumann, Ernst-Jan Speel, Yoshihiro Takihara, Bradly G. Wouters, Jan Willem Voncken*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Although the MK3 gene was originally found deleted in some cancers, it is highly expressed in others. The relevance of MK3 for oncogenesis is currently not clear. We recently reported that MK3 controls ERK activity via a negative feedback mechanism. This prompted us to investigate a potential role for MK3 in cell proliferation. We here show that overexpression of MK3 induces a proliferative arrest in normal diploid human fibroblasts, characterized by enhanced expression of replication stress- and senescence-associated markers. Surprisingly, MK3 depletion evokes similar senescence characteristics in the fibroblast model. We previously identified MK3 as a binding partner of Polycomb Repressive Complex 1 (PRC1) proteins. In the current study we show that MK3 overexpression results in reduced cellular EZH2 levels and concomitant loss of epigenetic H3K27me3-marking and PRC1/chromatin-occupation at the CDKN2A/INK4A locus. In agreement with this, the PRC1 oncoprotein BMI1, but not the PCR2 protein EZH2, bypasses MK3-induced senescence in fibroblasts and suppresses P16INK4A expression. In contrast, BMI1 does not rescue the MK3 loss-of-function phenotype, suggesting the involvement of multiple different checkpoints in gain and loss of MK3 function. Notably, MK3 ablation enhances proliferation in two different cancer cells. Finally, the fibroblast model was used to evaluate the effect of potential tumorigenic MK3 driver-mutations on cell proliferation and M/SAPK signaling imbalance. Taken together, our findings support a role for MK3 in control of proliferation and replicative life-span, in part through concerted action with BMI1, and suggest that the effect of MK3 modulation or mutation on M/SAPK signaling and, ultimately, proliferation, is cell context-dependent.
Original languageEnglish
Article numbere0118840
JournalPLOS ONE
Volume10
Issue number4
DOIs
Publication statusPublished - 8 Apr 2015

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