A method of producing a recombinant biological product, which method employs a mammalian producer cell culture, comprises the steps of generating a biomass of mammalian producer during an initial phase of cell culture, and causing an increase in a level of one or more of the miRNA molecules of Table 1 within the mammalian producer cells once a desired concentration of mammalian producer cells has been achieved. The method may also comprise the step of increasing a level of an inhibitor of one or more of the miRNA molecules of Table 1 within the mammalian producer cells at the start of or during an initial phase of culture.