We obtain explicit realizations of holographic renormalization group (RG) flows from M-theory, from E^2,1 × Spin(7) at UV to AdS₄ × S̃⁷ (squashed S⁷) at IR, from E^2,1 × CY4 at UV to AdS₄ × Q^1,1,1 at IR, and from E^2,1 × HK (hyperKahler) at UV to AdS₄ × N^0,1,0 at IR. The dual type-IIA string theory configurations correspond to D2-D6 brane systems where D6-branes wrap supersymmetric four-cycles. We also study the Penrose limits and obtain the pp-wave backgrounds for the above configurations. Besides, we study some examples of non-supersymmetric and supersymmetric flows in five-dimensional gauge theories.