Department of Biochemistry and Molecular Biology, School of Basic Medicine, Chongqing Medical University, 400016 Chongqing, China.
Molecular Medicine and Cancer Research Center, Chongqing Medical University, 400016 Chongqing, China.
Front Biosci (Landmark Ed). 2023 May 25;28(5):102. doi: 10.31083/j.fbl2805102.
rRNA-derived small RNAs (rsRNAs) represent a novel class of small non-coding RNAs (sncRNAs), produced by the specific cleavage of rRNAs; however, their roles in tumor development are unclear. In the present study, we explored the effect of a kind of rsRNA-28S, which originates from 28S rRNA, on the chemoresistance of prostate cancer cells and the mechanisms underlying its effect.
Quantitative reverse transcription PCR (RT-PCR) was performed to quantify rsRNA-28S levels in serum samples taken from prostate cancer patients. DU-145R cells, which are resistant to both paclitaxel and docetaxel, were generated from parental DU-145 cells. Northern blot was conducted to detect cellular rsRNA-28S levels following drug treatments. To verify the effect of rsRNAs-28S on chemoresistance, antisense oligonucleotides were utilized to block rsRNA-28S functions, and a series of assays were further performed, such as cell viability, cell proliferation, colony formation and tumor sphere formation. The target gene of rsRNA-28S was explored using dual-luciferase reporter gene assay.
The rsRNA-28S level was reduced in the serum samples of patients who received chemotherapy compared to that of patients who did not. Furthermore, the rsRNA-28S level was remarkably declined in DU-145R cells, and drug treatments decreased the levels of rsRNA-28S in DU-145 and DU-145R cells. Moreover, rsRNA-28S inhibition enhanced the chemoresistance of prostate cancer cells as well as their cancer stem cell characteristics. Mechanistically, the prostaglandin I2 synthase () gene transcript was verified as a target of rsRNA-28S, as rsRNA-28S inhibited the translation of PTGIS mRNA by directly binding the 3' untranslated region of PTGIS mRNA. rsRNA-28S inhibition was also found to increase PTGIS abundance, and PTGIS overexpression significantly enhanced prostate cancer cell chemoresistance.
Our findings indicate that rsRNA-28S attenuates prostate cancer cell chemoresistance by downregulating its target gene . This study not only greatly contributes to systematic identification and functional elucidation of chemoresistance relevant rsRNAs, but also promotes rsRNA-included combinatorial therapeutic regimens for cancer.
rRNA 衍生的小 RNA（rsRNA）代表了一类新型的小非编码 RNA（sncRNA），由 rRNA 的特异性切割产生; 然而，它们在肿瘤发展中的作用尚不清楚。在本研究中，我们探讨了一种源自 28S rRNA 的 rsRNA-28S 对前列腺癌细胞化疗耐药性的影响及其作用机制。
采用定量逆转录 PCR（RT-PCR）检测前列腺癌患者血清样本中 rsRNA-28S 的水平。从亲本 DU-145 细胞中生成对紫杉醇和多西紫杉醇均耐药的 DU-145R 细胞。用Northern blot 检测药物处理后细胞内 rsRNA-28S 的水平。为了验证 rsRNA-28S 对化疗耐药性的影响，利用反义寡核苷酸阻断 rsRNA-28S 的功能，并进一步进行一系列实验，如细胞活力、细胞增殖、集落形成和肿瘤球体形成。通过双荧光素酶报告基因检测探索 rsRNA-28S 的靶基因。
与未接受化疗的患者相比，接受化疗的患者血清样本中的 rsRNA-28S 水平降低。此外，rsRNA-28S 在 DU-145R 细胞中显著下调，药物处理也降低了 DU-145 和 DU-145R 细胞中 rsRNA-28S 的水平。此外，rsRNA-28S 抑制增强了前列腺癌细胞的化疗耐药性及其癌症干细胞特性。在机制上，前列腺素 I2 合酶（）基因转录本被验证为 rsRNA-28S 的靶标，因为 rsRNA-28S 通过直接结合 PTGIS mRNA 的 3'非翻译区抑制 PTGIS mRNA 的翻译。还发现 rsRNA-28S 抑制可增加 PTGIS 的丰度，而过表达 PTGIS 可显著增强前列腺癌细胞的化疗耐药性。
我们的研究结果表明，rsRNA-28S 通过下调其靶基因来减弱前列腺癌细胞的化疗耐药性。本研究不仅极大地促进了化疗耐药相关 rsRNA 的系统鉴定和功能阐明，而且为癌症的 rsRNA 包含联合治疗方案提供了新的思路。
