Figure 7

Knockdown of LAMP3 reduces invasion of spheroids into collagen. (A) Expression of LAMP3 mRNA in control cells versus LAMP3 knockdown cells. (B) Spheroid size of MDA-MB-231 control and LAMP3 knockdown spheroids after 4 days of growth. Results are from two independent experiments with 32 replicates each. (C) F-actin staining of MDA-MB-231 spheroids of control and LAMP3 knockdown cells, after 6 days of invasion in collagen. Bar is 100 μm, original magnification is 50 x. (D) Surface of collagen invaded by MDA-MB-231 control and LAMP3 knockdown spheroids during 72 hours. (E) Collagen invasion of a mixed MDA-MB-231 spheroid after 6 days. Control cells were labeled with CellTracker Green and LAMP3 knockdown cells were labeled with CellTracker Orange. Control and LAMP3 knockdown cells were mixed in a 1:1 ratio. Bar is 100 μm, original magnification is 100 x. (F) Quantification of E. The total amount of green and red signal was analyzed in five different zones: the spheroid body and four consecutive invasive zones, n = 5. LAMP3, lysosomal-associated membrane protein 3.