The effect of non-uniform rotation with a jet profile on the drift and Kelvin - Helmholtz instabilities in a tandem mirror is investigated numerically. Certain regimes of the flow parameters are found where the drift instability is nearly suppressed and the transverse Kelvin - Helmholtz instability is not induced. The growth rate of the Kelvin - Helmholtz instability can also be reduced to almost zero by a sufficiently large rotation frequency or by a radial electric field with moderate shear. The wave - flow resonant interaction may account for the stabilizing effect of sheared flow on drift and Kelvin - Helmholtz instabilities.