(A, E) HMVEC-dLy cells could hardly form any tube like structure with addition of conditioned medium (CM) from 468GFP cells at (A) 4 h and (E) 8 h. (B, F) HMVEC-dLy cells could form complete tubes as early as at (B) 4 h and (F) 8 h with 468LN CM. (C, G) VEGF-D knock down (KD) in 468LN cells, resulted in reduction in tube formation at both time points. (D, H) Again, addition of rVEGF-D in the CM of VEGF-D-KD 468LN cells stimulated tube formation. (I, J) Quantitative data for above observations are presented as (I) tube number index and (J) branching point index showing significant increase in tube and branch formation in presence of 468LN cell CM, but not 468GFP CM. Moreover VEGF-D KD in 468LN cells could block this function and HMVEC-dLy cells regained this function when rVEGF-D was added. Data represent mean (n = 3) ± SE. *,P<0.05; **,P<0.01.