Fig. 5

MYCN promotes tumor growth by repressing ELOVL2 in vitro and vivo. a and b BE(2)-C cells stably expressing the negative control or MYCN shRNA were further infected with a lentivirus expressing ELOVL2 shRNA. SK-N-AS cells stably expressing GFP or MYCN were further infected with a lentivirus expressing ELOVL2. The BE(2)-C (a) and SK-N-AS (b) cell proliferation rate was determined using CCK-8 and a spectrophotometer at OD450. c and d BE(2)-C (c) and SK-N-AS (d) cells were treated as described in (a). Cells were stained with PI for 72 h, and the change in the cell cycle was measured by flow cytometry. e, f and g BE(2)-C were treated as described in (a) and injected subcutaneously into nude mice (n = 5 for each group). Tumors were compared (e) at the end of the experiment. Tumor growth curves (f) were measured starting at 7 days after inoculation. The DHA concentration of tumors (g) was measured by ELISA. h, i and j SK-N-AS were treated as described in (a) and injected subcutaneously into nude mice (n = 5 for each group). Tumors were compared (h) at the end of the experiment. Tumor growth curves (i) were measured starting at 7 days after inoculation. The DHA concentration of tumors (j) was measured by ELISA. k Representative IHC analysis of ELOVL2 and H2AK119ub protein expression in SK-N-AS cells stably expressing GFP or MYCN (up) and BE(2)-C cells stably expressing the negative control or MYCN shRNA (low). l, m, n and o The results of IHC analysis of ELOVL2 and H2AK119ub protein expression are presented as bar graphs of the mean number of the ELOVL2 and H2AK119ub positive rate. p and q ELOVL2 expression significantly correlated with MYCN expression in ALL (P) and MYCN (Q) amplification clinical tumor samples from the SEQC database. *P < 0.05; **P < 0.01; ***P < 0.001