The cloning and heterologous expression of human T2 RNase6PL are disclosed.Further disclosed are methods for preventing, inhibiting and/or reversing cellmotility, actin filament assembly or disassembly, proliferation, colonization,differentiation, accumulation and/or development of abnormal cells in asubject is disclosed. The methods are effected by administering to the subjecta therapeutically effective amount of a RNase6PL ribonuclease or closehomologues thereof.