Coordination of Centrosome Homeostasis and DNA Repair Is Intact in MCF-7 and Disrupted in MDA-MB 231 Breast Cancer Cells

Abstract

When cells encounter substantial DNA damage, critical cell cycle events are halted while DNA repair mechanisms are activated to restore genome integrity. Genomic integrity also depends on proper assembly and function of the bipolar mitotic spindle, which is required for equal chromosome segregation. Failure to execute either of these processes leads to genomic instability, aging, and cancer. Here, we show that following DNA damage in the breast cancer cell line MCF-7, the centrosome protein centrin2 moves from the cytoplasm and accumulates in the nucleus in a xeroderma pigmentosum complementation group C protein (XPC)–dependent manner, reducing the available cytoplasmic pool of this key centriole protein and preventing centrosome amplification. MDA-MB 231 cells do not express XPC and fail to move centrin into the nucleus following DNA damage. Reintroduction of XPC expression in MDA-MB 231 cells rescues nuclear centrin2 sequestration and reestablishes control against centrosome amplification, regardless of mutant p53 status. Importantly, the capacity to repair DNA damage was also dependent on the availability of centrin2 in the nucleus. These observations show that centrin and XPC cooperate in a reciprocal mechanism to coordinate centrosome homeostasis and DNA repair and suggest that this process may provide a tractable target to develop treatments to slow progression of cancer and aging.

Calcium-Binding Capacity of Centrin2 Is Required for Linear POC5 Assembly but Not for Nucleotide Excision Repair

“…It thus seems likely that the nuclear localisation of centrin2 is an important determinant of NER efficiency. Several studies have indicated that this localisation depends on centrin2 interacting directly with XPC [36,56,57]. A role for centrin2 SUMOylation in regulating this interaction and thus, the movement of centrin2 into the nucleus for NER, was suggested from RNAi experiments that disrupted the SUMOylation machinery [58].…”

“…The role played by centrin2 in NER is unclear: in vitro NER can be carried out in its absence, although it increases NER activity somewhat [32–35]. Nevertheless, centrin2 moves to the nucleus after UV irradiation in an XPC-dependent manner and is required for efficient repair of UV-induced DNA lesions in both human and chicken cells [25,36]. …”

Creatine kinase brain overexpression protects colorectal cells from various metabolic and non‐metabolic stresses

“…Cells were centrifuged again at 1,000 × g , resuspended in 1 ml of PI/RNase solution (40 µg/ml PI and 50 µg/ml RNase in PBS), and incubated in PI/RNase solution at 4°C overnight before analysis. FACS analysis was performed in PI/RNase solution on a Becton Dickinson FACScan [Acu et al, 2010]. …”

Centrins in unicellular organisms: functional diversity and specialization

“…Recent studies of centrin2 in breast cancer cell lines MCF-7 suggest a possible link between centrin function at the nucleus and the centrosomes (Acu et al 2010). Upon DNA damage, centrin2 is recruited to the nucleus for NER function in an XPC-dependent manner, leaving less centrin present at the centrosomes and thus causing cell cycle arrest, whereas in XPC-deficient MDA-MB231 and XPC-null fibroblast cells, centrin lost the ability to relocate from the centrosomes to the nucleus and centrosome amplification occurred following DNA damage.…”