Scull Catherine E, Twa Guy, Zhang Yinfeng, Yang Naiheng J, Hunter Robert N, Augelli-Szafran Corinne E, Schneider David A
Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Southern Research, Birmingham, AL 35205, USA.
Cancers (Basel). 2023 Jun 23;15(13):3303. doi: 10.3390/cancers15133303.
Cancer cells are especially sensitive to perturbations in ribosome biogenesis as they rely on finely tuned protein homeostasis to facilitate their rapid growth and proliferation. While ribosome synthesis and cancer have a well-established relationship, ribosome biogenesis has only recently drawn interest as a cancer therapeutic target. In this study, we exploited the relationship between ribosome biogenesis and cancer cell proliferation by using a potent ribosome biogenesis inhibitor, RBI2 (Ribosome Biogenesis Inhibitor 2), to perturb cancer cell growth and viability. We demonstrate herein that RBI2 significantly decreases cell viability in malignant melanoma cells and breast cancer cell lines. Treatment with RBI2 dramatically and rapidly decreased ribosomal RNA (rRNA) synthesis, without affecting the occupancy of RNA polymerase I (Pol I) on the ribosomal DNA template. Next-generation RNA sequencing (RNA-seq) revealed that RBI2 and previously described ribosome biogenesis inhibitor CX-5461 induce distinct changes in the transcriptome. An investigation of the content of the pre-rRNAs through RT-qPCR revealed an increase in the polyadenylation of cellular rRNA after treatment with RBI2, constituting a known pathway by which rRNA degradation occurs. Northern blotting revealed that RBI2 does not appear to impair or alter rRNA processing. Collectively, these data suggest that RBI2 inhibits rRNA synthesis differently from other previously described ribosome biogenesis inhibitors, potentially acting through a novel pathway that upregulates the turnover of premature rRNAs.
癌细胞对核糖体生物合成的扰动特别敏感，因为它们依赖精细调节的蛋白质稳态来促进其快速生长和增殖。虽然核糖体合成与癌症之间的关系已得到充分确立，但核糖体生物合成直到最近才作为一种癌症治疗靶点引起关注。在本研究中，我们通过使用一种有效的核糖体生物合成抑制剂RBI2（核糖体生物合成抑制剂2）来干扰癌细胞的生长和活力，从而利用核糖体生物合成与癌细胞增殖之间的关系。我们在此证明，RBI2显著降低恶性黑色素瘤细胞和乳腺癌细胞系中的细胞活力。用RBI2处理可显著且迅速地降低核糖体RNA（rRNA）的合成，而不影响RNA聚合酶I（Pol I）在核糖体DNA模板上的占据情况。下一代RNA测序（RNA-seq）显示，RBI2和先前描述的核糖体生物合成抑制剂CX-5461在转录组中诱导不同的变化。通过RT-qPCR对前体rRNA含量的研究表明，用RBI2处理后细胞rRNA的多聚腺苷酸化增加，这构成了rRNA降解发生的已知途径。Northern印迹分析显示，RBI2似乎不会损害或改变rRNA的加工过程。总的来说，这些数据表明，RBI2与其他先前描述的核糖体生物合成抑制剂不同，它通过一种上调过早rRNA周转的新途径来抑制rRNA合成。
