Curcumin nano-prodrug induces multi-phase cell cycle arrest in colorectal cancer through suppression of CDKs and specific down-regulation of PLK1

Aberrant activation of cell cycle proteins leads to tumor progression in most cancer types. While 5-fluorouracil (5-Fu)-based chemotherapy remains the first-line treatment strategy for colorectal cancer (CRC), more than 40% of patients with advanced CRC do not benefit from the regimen. Herein, a chemically modified curcumin (mCur) was developed to explore its curative effect on CRC and reveal its potential role in cell cycle regulation. Amphiphilic mCur could self-assemble into positively charged nano-micelles, hence facilitating high cellular uptake and anticancer activity. Multi-phase cell cycle arrest, induced by both mCur and Cur, was first observed in HCT 116 ​cells. This phenomenon was mainly attributed to the Cur/mCur mediated downregulation of cyclin-dependent kinases (CDKs) and their direct interactions. Moreover, mCur and Cur treatments generated distinct phenotypic signatures. In particular, mCur induced distinct dynamic fluctuations in cell cycle and a relatively higher proportion of cells in the G2/M phase than Cur, and specifically triggered the impaired expression of polo-like kinase 1 (PLK1). An in vivo evaluation using a CRC patient-derived tumor xenograft (PDX) model indicated that mCur exhibited better antitumor effects via more significant downregulation of PLK1 in PLK1^high PDX, with no obvious systemic toxicity. Collectively, our study revealed a unique multi-phase cell cycle arrest effect of Cur-based antitumor agents and highlighted the potential of mCur as a PLK1-targeted inhibitor for CRC therapy.