Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-kB signaling pathway

Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. The NF-kBsignalling pathway deregulation has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-kBwas hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-kB inhibitor. The concomitant combination of Curcumin+OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion oftheir resistant phenotype, through the inhibition of the NF-kBsignalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-KB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells thatwere more efficiently down-regulated after OXA+Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-kBpathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastaseswas associated with response to OXA+Curcumin.In conclusion, we suggest that combination of OXA+Curcumincould be an effective treatment in CRC patients after progression to OXA-based chemotherapy being CXCL1a good candidate predictive marker to this treatment. Stable colorectal cancer-derived cell lines sensitive to oxaliplatin (HT29) and resistant to oxaliplatin (HTOXAR3) were cultured under basal conditions (without treatment) or in the presence of oxaliplatin or oxaliplatin and curcumin in triplicate. cell type comparison; treatment comparison