Chemotherapy has been widely used in clinical practice for cancer treatment. A major challenge for a successful chemotherapy is to potentiate the anticancer activity, whilst reducing the severe side effects. In this context, we design a bio-inspired protein-gold nanoconstruct (denoted as AFt-Au hereafter) with a core-void-shell structure which exhibits a high selectivity towards carcinoma cells. Anticancer drug 5-fluorouracil (5-FU) can be sequestered into the void space of the construct to produce an integrated nanoscale hybrid AFt-AuFU that exhibits an increased cellular uptake of 5-FU. More importantly, AFt-Au, serving as a bio-nano-chemosensitizer, renders carcinoma cells more susceptible to 5-FU by cell-cycle regulation, and thus, leads to a dramatic decrease of the IC50 value (i.e. the drug concentration required to kill 50% of the cell population) of 5-FU in HepG2 cells from 138.3 μM to 9.2 μM. Besides HepG2 cells, a remarkably enhanced anticancer efficacy and potentially reduced side effects are also achieved in other cell lines. Our further work reveals that the drug 5-FU is internalized into cells with AFt-Au primarily via receptor-mediated endocytosis (RME). After internalization, AFt-AuFU colocalizes with lysosomes which trigger the release of 5-FU under acidic conditions. Overall, our approach provides a novel procedure in nanoscience that promises an optimal chemotherapeutic outcome.