Increasing evidence indicates that long noncoding RNAs (lncRNAs) have important roles in various physiological processes and dysfunction of lncRNAs could be a prevalent cause in human diseases. Here we functionally characterized the nuclear-enriched lncRNA SNHG1, which is highly expressed in multiple types of cancer. We also provide evidence that SNHG1 promotes cancer cell growth by regulating gene expression both in cis and in trans. SNHG1 was involved in the AKT signaling pathway as it promotes the neighboring transcription of the protein-coding gene SLC3A2 in cis by binding the Mediator complex to facilitate the establishment of enhancer-promoter interaction. In trans, SNHG1 directly interacted with central domain of FUBP1 and antagonize the binding of FBP-interacting repressor to FUBP1, thereby coordinating the expression of the oncogene MYC. Collectively, our findings demonstrate that lncRNA SNHG1 can function both in cis and in trans with distinct mechanisms to regulate transcription, promoting tumorigenesis and cancer progression.