document: U87MG cells were treated with 1 μM of VLP-based samples (Qβ VLPs and TrQβ@b-3WJsiEGFR Let-7g) for 72 h and then seeded into 96-well plates (1,000 cells per well). After 72 h of incubation, the cells were washed with PBS buffer (pH=7.4) and incubated with XTT solution at 37°C for 30 min (n=8). Cell growth rate was analysed by measuring the absorbance at 450 nm using an SpectraMax M2 microtiter plate reader.