Role of miR-30 in tumor progression and metastasis. A. 4T1 mammary cancer cells were transiently transfected with miR-30a KD, Pre-miR-30a, and miR-159 KD control oligos. Next, cells were injected in the mammary fat pad of BALB/c mice (5–6 mice per group), and tumor volume (left panel) and weight (central panel) were registered after 3 weeks. At the end of the 3 weeks, tumors were disaggregated and plated in a mammosphere formation assay. Number of mammospheres was counted in triplicates for each condition (right panel). P value under 0.05 is represented with an asterisk (*). B. growth curve for the experiment described in (A). Quantification of tumor volume was performed from day 14 (when tumors are detectable) to day 21. C. An independent experiment was performed in a similar way to (A), using miR-30 family KD oligos instead of single miR-30a KD P value under 0.05 (two-tailed student t test) is represented with a (*).