p53 Activates the Long Noncoding RNA Pvt1b to Inhibit Myc and Suppress Tumorigenesis.
P53 激活长链非编码 RNA Pvt1b 抑制 Myc，抑制肿瘤发生。
- 作者列表："Olivero CE","Martínez-Terroba E","Zimmer J","Liao C","Tesfaye E","Hooshdaran N","Schofield JA","Bendor J","Fang D","Simon MD","Zamudio JR","Dimitrova N
:The tumor suppressor p53 transcriptionally activates target genes to suppress cellular proliferation during stress. p53 has also been implicated in the repression of the proto-oncogene Myc, but the mechanism has remained unclear. Here, we identify Pvt1b, a p53-dependent isoform of the long noncoding RNA (lncRNA) Pvt1, expressed 50 kb downstream of Myc, which becomes induced by DNA damage or oncogenic signaling and accumulates near its site of transcription. We show that production of the Pvt1b RNA is necessary and sufficient to suppress Myc transcription in cis without altering the chromatin organization of the locus. Inhibition of Pvt1b increases Myc levels and transcriptional activity and promotes cellular proliferation. Furthermore, Pvt1b loss accelerates tumor growth, but not tumor progression, in an autochthonous mouse model of lung cancer. These findings demonstrate that Pvt1b acts at the intersection of the p53 and Myc transcriptional networks to reinforce the anti-proliferative activities of p53.
肿瘤抑制因子 p53 在应激过程中转录激活靶基因抑制细胞增殖。p53 也与原癌基因 Myc 的抑制有关，但机制尚不清楚。在这里，我们鉴定了 Pvt1b，长链非编码 RNA (lncRNA) Pvt1 的 p53-dependent 亚型，在 Myc 下游表达 50kb, 由 DNA 损伤或致癌信号诱导，并在其转录位点附近积累。我们证明 Pvt1b RNA 的产生是必要的，并且足以抑制 cis 中的 Myc 转录，而不改变位点的染色质组织。抑制 Pvt1b 增加 Myc 水平和转录活性，促进细胞增殖。此外，在肺癌的自体小鼠模型中，Pvt1b 丢失加速肿瘤生长，但不加速肿瘤进展。这些发现证明 Pvt1b 作用于 p53 和 Myc 转录网络的交叉点，加强 p53 的抗增殖活性。
METHODS::In colorectal cancer (CRC), hepatic arterial infusion (HAI) chemotherapy may convert primarily unresectable CRC liver metastases (CLM) into resectability, although the risk of metastatic recurrence remains high after CLM ablation. We investigated the role of antitumour immunity invoked by first-line oxaliplatin-HAI for long-term CLM outcome. In a prospective study cohort of primarily unresectable CLM, we assessed patients' fms-related tyrosine kinase 3 ligand (FLT3LG) in serum, reflecting opportune intratumoural immune activity, at baseline and following 1-3 sequences of oxaliplatin-HAI. The end points were CLM resectability and overall survival. Patients who presented an immediate twofold increment of circulating FLT3LG during the treatment and at its completion were scored as CLM resectable (16.4% with both features), were alive at final follow-up 8-12 years later. All patients experienced FLT3LG increase during the treatment course, but those who remained unresectable or had the disease converted but presented a slow and gradual FLT3LG accretion, later died of the metastatic disease. These data provide further support to our previous findings that tumour-directed immunity invoked by oxaliplatin-containing therapy predicts excellent outcome of early advanced CRC if macroscopic tumour ablation is rendered possible by the 'classic' tumour response to the cytotoxic treatment.
METHODS::Prostate cancer is one of the primary causes of death around the world. As an important drug, flutamide has been used in the clinical diagnosis of prostate cancer. However, the over dosage and improper discharge of flutamide could affect the living organism. Thus, it necessary to develop the sensor for detection of flutamide with highly sensitivity. In this paper, we report the synthesis of lanthanum cobaltite decorated halloysite nanotube (LCO/HNT) nanocomposite prepared by a facile method and evaluated for selective reduction of flutamide. The as-prepared LCO/HNT nanocomposite shows the best catalytic performance towards detection of flutamide, when compared to other bare and modified electrodes. The good electrochemical performance of the LCO/HNT nanocomposite modified electrode is ascribed to abundant active sites, large specific surface area and their synergetic effects. Furthermore, the LCO/HNT modified electrode exhibits low detection limit (0.002 μM), wide working range (0.009-145 μM) and excellent selectivity with remarkable stability. Meaningfully, the developed electrochemical sensor was applied in real environmental samples with an acceptable recovery range.
METHODS::Several studies have indicated that cancer-associated fibroblasts (CAFs) could promote cancer progression in many malignancies. However, the mechanism by which CAFs promote the growth and metastasis of lung cancer remains poorly defined. In the present study, CAFs and normal fibroblasts (NFs) were isolated from human lung cancer and adjacent tissue. The data showed that the conditional medium (CM) of CAFs could increase the proliferation, migration and invasion of lung cancer cells. Vascular cell adhesion molecule-1 (VCAM-1) showed a higher expression in CAF-CM than NF-CM, and blocking VCAM-1 in CAF-CM attenuated the proliferation and invasion of cancer cells. Further, the results showed that VCAM-1 secreted from CAFs activated AKT and MAPK signaling via receptor α4β1 integrin (very-late antigen (VLA)-4) in lung cancer cells. Moreover, CAFs promoted VCAM-1 expression and tumor growth in vivo. Additionally, bioinformatics analysis indicated a positive correlation on the CAF marker protein alpha-smooth muscle actin (α-SMA) and VCAM-1 expression, which was associated with a poor prognosis in lung cancer patients. These findings demonstrate that the VCAM-1 secreted from CAFs enhances growth and invasion by activating the AKT and MAPK signaling of lung cancer cells.