Regorafenib inhibits colorectal tumor growth through PUMA-mediated apoptosis
Menée sur des lignées cellulaires et à l'aide de xénogreffes de cancer colorectal, cette étude met en évidence le rôle joué par la protéine PUMA dans la régulation de la sensibilité des cellules tumorales au regorafenib
Résumé en anglais
Purpose: Regorafenib, a multi-kinase inhibitor targeting the Ras/Raf/MEK/ERK pathway, has recently been approved for the treatment of metastatic colorectal cancer (CRC). However, the mechanisms of action of regorafenib in CRC cells have been unclear. We investigated how regorafenib suppresses CRC cell growth and potentiates effects of other chemotherapeutic drugs.
Experimental Design: We determined whether and how regorafenib induces the expression of PUMA, a p53 target and a critical mediator of apoptosis in CRC cells. We also investigated whether PUMA is necessary for the killing and chemosensitization effects of regorafenib in CRC cells. Furthermore, xenograft tumors were used to test if PUMA mediates the in vivo antitumor, antiangiogenic and chemosensitization effects of regorafenib.
Results: We found that regorafenib treatment induces PUMA in CRC cells irrespective of p53 status through the NF-κB pathway following ERK inhibition and glycogen synthase kinase 3β (GSK3β) activation. Upregulation of PUMA is correlated with apoptosis induction in different CRC cell lines. PUMA is necessary for regorafenib-induced apoptosis in CRC cells. Chemosensitization by regorafenib is mediated by enhanced PUMA induction through different pathways. Furthermore, deficiency in PUMA abrogates the in vivo antitumor, antiangiogenic and chemosensitization effects of regorafenib.
Conclusions: Our results demonstrate a key role of PUMA in mediating the anticancer effects of regorafenib in CRC cells. They suggest that PUMA induction can be used as an indicator of regorafenib sensitivity, and also provide a rationale for manipulating the apoptotic machinery to improve the therapeutic efficacy of regorafenib and other targeted drugs.
