From Thomson's(Kelvin) equation It follows that with a positive curvature (for example, for a spherical drop) the pressure of saturated steam over a curved surface (above the drop) will be greater, the greater the curvature (or less drop radius). The dispersion changes solubility and shifts the balance. For solubility, a ratio similar to the Kelvin equation is obtained. Play your example with the Kelvin equation.

Change in pressure results into not only the the vapor pressure but also the other physical characteristics of the uncritical solvents like viscosity, conductivity, solvation ability, conductivity, etc. The change in salvation ability and in turn dissolution tendency is attributed to tunability or redesigning the properties of the solventwhich reflects upon the change in behavior of solvent with solute in terms of solute-solvent interaction and subsequently the solubility.

Let us consider that we put the oxide nanoparticles in solvothermal autoclave, then how much particles will dissolve in the solution? I think within there are no particles will dissolves under usual range (0-250) C. But when when we add a base or acid, I think, the high pressure and temperature will induce reactions between solution components even when they non-intracted under usual lab conditions. So the pressure and temperature are just induce factors to intiate the reaction for weak reactions. The question can be explained on chemical base not on physical base.