Blocking JNK activity by its pharmacological inhibitor (SP600125) alone was not able to attenuate the inhibitory effect of metformin on cell viability; however, addition of Rac1 inhibitor (NSC23766) or Cdc42 inhibitor (ML141) along with SP600126 (JNK inhibitor) significantly protected neuroblastoma cells against metformin toxicity (Fig. 6E). This evidence concerns the gene RAC1 and neuroblastoma.