Cholecalciferol (vitamin D3) is a natural form of vitamin D. After metabolism is activated, cholecalciferol induces cell differentiation and prevents cancer cell proliferation. Modulates the proliferation and differentiation of both normal and cancer cells. Has antiproliferative and antimetastatic effects on breast, colon, and prostate cancer cells. Activated vitamin D receptors in intestine and bone maintain calcium absorbance and homeostasis.