Control of replication stress and mitosis in colorectal cancer stem cells through the interplay of PARP1, MRE11 and RAD51

Gwenola Manic, Martina Musella, Francesca Corradi, Antonella Sistigu, Sara Vitale, Sara Soliman Abdel Rehim, Luca Mattiello, Eva Malacaria, Claudia Galassi, Michele Signore, Matteo Pallocca, Stefano Scalera, Frauke Goeman, Francesca De Nicola, Andrea Guarracino, Rosa Pennisi, Fabrizio Antonangeli, Francesca Sperati, Marta Baiocchi, Mauro BiffoniMaurizio Fanciulli, Marcello Maugeri-Saccà, Annapaola Franchitto, Pietro Pichierri, Ruggero De Maria, Ilio Vitale

Research output: Contribution to journalArticlepeer-review


Cancer stem cells (CSCs) are tumor subpopulations driving disease development, progression, relapse and therapy resistance, and their targeting ensures tumor eradication. CSCs display heterogeneous replication stress (RS), but the functionality/relevance of the RS response (RSR) centered on the ATR-CHK1 axis is debated. Here, we show that the RSR is efficient in primary CSCs from colorectal cancer (CRC-SCs), and describe unique roles for PARP1 and MRE11/RAD51. First, we demonstrated that PARP1 is upregulated in CRC-SCs resistant to several replication poisons and RSR inhibitors (RSRi). In these cells, PARP1 modulates replication fork speed resulting in low constitutive RS. Second, we showed that MRE11 and RAD51 cooperate in the genoprotection and mitosis execution of PARP1-upregulated CRC-SCs. These roles represent therapeutic vulnerabilities for CSCs. Indeed, PARP1i sensitized CRC-SCs to ATRi/CHK1i, inducing replication catastrophe, and prevented the development of resistance to CHK1i. Also, MRE11i + RAD51i selectively killed PARP1-upregulated CRC-SCs via mitotic catastrophe. These results provide the rationale for biomarker-driven clinical trials in CRC using distinct RSRi combinations.

Original languageEnglish
Pages (from-to)2060-2082
Number of pages23
JournalCell Death and Differentiation
Issue number7
Publication statusPublished - Jul 2021


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