lncRNA THAP9-AS1 Promotes Pancreatic Ductal Adenocarcinoma Growth and Leads to a Poor Clinical Outcome via Sponging miR-484 and Interacting with YAP.
LncRNA THAP9-AS1 通过海绵 miR-484 和 YAP 相互作用促进胰腺导管腺癌生长并导致不良的临床结局。
- 作者列表："Li N","Yang G","Luo L","Ling L","Wang X","Shi L","Lan J","Jia X","Zhang Q","Long Z","Liu J","Hu W","He Z","Liu H","Liu W","Zheng G
PURPOSE:Long noncoding RNAs (lncRNA) have been observed in various cancer types. Our bioinformatic analysis of existing databases demonstrated overexpression of lncRNA THAP9-AS1 in pancreatic ductal adenocarcinoma (PDAC). We aimed to investigate the roles and mechanisms of THAP9-AS1 in PDAC. EXPERIMENTAL DESIGN:The overexpression of THAP9-AS1 in samples of patients with pancreatic cancer was characterized and was associated with clinical outcomes. The nonprotein coding property of the THAP9-AS1 was verified. Various in vitro and in vivo experiments were performed to investigate the interaction between THAP9-AS1 and YAP signaling. RESULTS:We demonstrated that lncRNA THAP9-AS1 is overexpressed in PDAC in multiple patient sample sets, which is significantly associated with poor outcome of patients with PDAC. THAP9-AS1 promotes PDAC cells growth both in vitro and in vivo. THAP9-AS1 exerts its effects via enhancing YAP signaling. Ectopic YAP expression overcame the effects of THAP9-AS1 knockdown. Inversely, YAP knockdown diminished the effects of THAP9-AS1 overexpression. THAP9-AS1 acts as a competing endogenous RNA for miR-484, leading to YAP upregulation. Moreover, THAP9-AS1 binds to YAP protein and inhibits the phosphorylation-mediated inactivation of YAP by LATS1. Reciprocally, YAP/TEAD1 complex promotes THAP9-AS1 transcription to form a feed-forward circuit. Importantly, THAP9-AS1 level positively correlates with YAP expression in PDAC tissues. YAP overexpression also predicts a poor outcome in patients with PDAC. CONCLUSIONS:Our findings indicate that THAP9-AS1 plays an important role in PDAC growth via enhancing YAP signaling, which in turn also modulates THAP9-AS1 transcription. THAP9-AS1/YAP axis may serve as a potential biomarker and therapeutic target for PDAC treatment.
目的: 长链非编码 rna (lncRNA) 已在各种癌症类型中观察到。我们对现有数据库的生物信息学分析证明了胰腺导管腺癌 (PDAC) 中 lncRNA THAP9-AS1 的过表达。我们旨在研究 THAP9-AS1 在 PDAC 中的作用和机制。 实验设计: 胰腺癌患者样本中 THAP9-AS1 过表达的特征与临床结果相关。验证了 THAP9-AS1 的非蛋白编码特性。通过体外和体内实验研究 THAP9-AS1 与 YAP 信号的相互作用。 结果: 我们证明了在多个患者样本集中，lncRNA THAP9-AS1 在 PDAC 中过表达，这与 PDAC 患者的不良结局显著相关。THAP9-AS1 促进 PDAC 细胞在体外和体内的生长。THAP9-AS1 通过增强 YAP 信号发挥作用。异位 YAP 表达克服了 THAP9-AS1 敲除的影响。相反，YAP 敲除降低了 THAP9-AS1 过表达的影响。THAP9-AS1 作为 miR-484 的竞争性内源性 RNA，导致 YAP 上调。此外，THAP9-AS1 与 YAP 蛋白结合，抑制 lats1 对 YAP 的磷酸化介导的失活。相互作用，YAP/TEAD1 复合物促进 THAP9-AS1 转录形成前馈电路。重要的是，在 PDAC 组织中，THAP9-AS1 水平与 YAP 表达呈正相关。YAP 过表达也预示着 PDAC 患者的不良结局。 结论: 我们的研究结果表明，THAP9-AS1 通过增强 YAP 信号在 PDAC 生长中起重要作用，YAP 信号反过来也调节 THAP9-AS1 转录。THAP9-AS1/YAP 轴可作为 PDAC 治疗的潜在生物标志物和治疗靶点。
METHODS::Pancreatic ductal adenocarcinoma (PDAC) is a disease of aging. The TP53 gene product regulates cell growth, aging, and cancer. To determine the important targets of TP53 in PDAC, we examined the expression of 440 proteins on a reverse phase protein array (RPPA) in PDAC-derived MIA-PaCa-2 cells which either had WT-TP53 or lacked WT-TP53. MIA-PaCa-2 cells have a TP53 mutation as well as mutant KRAS and represent a good in vitro model to study PDAC. RPPA analysis demonstrated expression of tumor promoting proteins in cells that lacked WT-TP53; and this feature could be reversed significantly when the cells were transfected with vector encoding WT-TP53 or treated with berberine or a modified berberine (BBR). Expression of miR-34a-associated signaling was elevated in cells expressing WT-TP53 compared to cells expressing mTP53. Results from in vivo studies using human PDAC specimens confirmed the in vitro results as the expression of miR-34a and associated signaling was significantly decreased in PDAC specimens compared to non-cancerous tissues. This study determined SERPINE1 as a miR-34a target with relevance to the biology of PDAC. Thus, we have identified a key target (SERPINE1) of the TP53/miR-34a axis that may serve as a potential biomarker for early detection of pancreatic cancer.
METHODS::Background: SLC6A14 (ATB0,+), a Na+/Cl-coupled transporter for neutral/cationic amino acids, is overexpressed in many cancers; It has been investigated as a target for improved liposomal drug delivery to treat liver cancer.Research design and methods: Here we explored the mechanism of ATB0,+-mediated entry of such liposomes. As ATB0,+ is highly-expressed in pancreatic cancer, we also examined the therapeutic utility of ATB0,+-targeted liposomal drug delivery to treat this cancer.Results: The uptake of lysine-conjugated liposomes (LYS-LPs) was greater in ATB0,+-positive MCF7 cells. The uptake process consisted of two steps: binding and internalization. The binding of LYS-LPs to MCF7 cells was higher than that of bare liposomes, and the process was dependent on Na+ and Cl-, and inhibitable by ATB0,+ substrates or blocker. In contrast, the internalization step was independent of lysine. The cellular entry of LYS-LPs facilitated by ATB0,+ occurred via endocytosis with transient endosomal degradation of ATB0,+ protein with subsequent recovery. Moreover, LYS-LPs also enhanced the uptake and cytotoxicity of gemcitabine in these cells in an ATB0,+-dependent manner.Conclusions: We conclude that ATB0,+ could be exploited for targeted drug delivery in the form of lysine-conjugated liposomes and that the approach represents a novel strategy for enhanced pancreatic cancer therapy.
METHODS:PURPOSE:Pre-operative prediction of histological response to neoadjuvant therapy aids decisions regarding surgical management of borderline resectable pancreatic cancer (BRPC). We elucidate correlation between pre-/post-treatment whole-tumor apparent diffusion coefficient (ADC) value and rate of tumor cell destruction. We newly verify whether post-treatment ADC value at the site of vascular contact predicts R0 resectability of BRPC. METHODS:We prospectively reviewed 28 patients with BRPC who underwent diffusion-weighted magnetic resonance imaging before neoadjuvant chemotherapy and surgery. Correlation between the percentage of tumor cell destruction and various parameters was analyzed. Strong parameters were assessed for their ability to predict therapeutic histological response and R0 resectability. RESULTS:Pre-/post-treatment whole-tumor ADC value correlated with tumor cell destruction rate by all parameters (R = 0.630/0.714, P 50% was determined at 1.40 × 10-3 mm2/s. It predicts histological response with 100% sensitivity, 81% specificity, and 89% accuracy. It predicts R0 with 88% sensitivity, 70% specificity, and 75% accuracy. CONCLUSIONS:Post-treatment whole-tumor ADC value may be a predictor of R0 resectability in patients with BRPC. Tumor cell destruction rate is indicated by the difference between pre-/post-treatment ADC values. This difference is strongly affected by the pre-treatment ADC value. The cutoff value of ADC at the site of vascular contact could not discriminate R0 resectability.