In cancer cells, accumulating evidence suggests the metabolic reprogramming is coupled to accelerated ribosome biogenesis and protein synthesis, which are required for increased proliferative growth of cancer cells. We demonstrated that glutamine is essential for activation of ribosomal RNA gene (rDNA) transcription through mTORC1-S6K1 and MYC signaling. Depletion of glutaminase 1 expression by siRNA markedly suppressed glutamine-driven 47/45S pre-rRNA synthesis. As MYC-dependent oncogenesis has also been linked to both elevated rDNA transcription and up-regulated glutaminolysis, and MYC-driven lymphoma displayed high sensitivity to either Pol I inhibitor or the glutaminase inhibitor, we therefore hypothesize that inhibition of glutaminolysis may enhance the efficacy of RNA polymerase I (Pol I) inhibitor, CX5461, which is on Phase I clinical trial in Peter MacCallum Cancer Centre, in treating MYC-driven malignancies. Pol I inhibitor CX5461 in combination with glutaminase inhibitor demonstrated synergistic effect on inhibiting cell proliferation and inducing cell death in Eμ-MYC B-lymphoma cells, which requires a functional p53 activity. Further investigation of the combinational effect in Eμ-MYC B lymphoma mouse model and the molecular mechanisms for the synergistic effect of combined inhibition of rDNA transcription and glutamine metabolism is actively performing.