Expression of cyclic RNA plasmacytoma variant translocation 1 in senescence of nucleus pulposus cells and its regulation mechanism / 中国组织工程研究

BACKGROUND: Cyclic RNA plasmacytoma variant translocation 1 (circPVT1) is involved in the senescence of fibroblasts, but the relationship of circPVT1 with nucleus pulposus senescence and its mechanism are still unclear. OBJECTIVE: To investigate the expression of circPVT1 in nucleus pulposus cell senescence and to explore its possible mechanism. METHODS: Human nucleus pulposus cells were cultured in vitro, and the senescence of nucleus pulposus cells was induced by ionizing radiation (5 Gy, 6 days). The expression of circPVT1 and let-7 mRNA was detected by real-time quantitative polymerase chain reaction (qRT-PCR). CircPVT1 siRNA and anti-let-7 were transfected into normal nucleus pulposus cells, which were divided into control group, si-NC+anti-NC group, si-circPVT1+anti-NC group, si-NC+anti-let-7 group, and si-circPVT1+anti-let-7 group. The expressions of circPVT1 and let-7 mRNA were detected by qRT-PCR. Cell counting kit-8 assay was used to detect the inhibition of cell proliferation. Plate cell clone formation assay was used to detect colony formation. Cell senescence was detected by SA-β-gal staining. The expressions of p21, p27, let-7 target high mobility group protein A2 (HMGA2) and KRAS were detected by western blot assay. Double luciferase activity assay was used to verify the relationship between let-7 and target regulation of HMGA2 and KRAS. RESULTS AND CONCLUSION: (1) Compared with normal nucleus pulposus cells, the expression of circPVT1 was decreased, while let-7 expression and the positive rate of SA-β-gal staining were increased in the irradiated cells (P < 0.05). (2) Compared with the control group and si-NC+anti-NC group, the si-circPVT1+anti-NC group appeared to have decreased expression of circPVT1 mRNA, HMGA2 and KRAS proteins and number of clones formed as well as increased let-7 mRNA expression, p21, p27 protein expression, cell inhibition rate and positive rate of SA-β-gal staining (P < 0.05). However, opposite changes were found in the si-NC+anti-let-7 group in relative to the control group (P < 0.05). (3) The expression of circPVT1 mRNA, clone formation, and expressions of HMGA2 and KRAS proteins in the si-circPVT1+anti-let-7 group were higher than those in the si-circPVT1+anti-NC group, and lower than those in the si-NC+anti-let-7 group. Let-7 mRNA expression, cell inhibition rate, positive rate of SA-β-gal staining, and expressions of p21 and p27 proteins in the si-circPVT1+anti-let-7 group were lower than those in the si-circPVT1+anti-NC group, and higher than those in the si-NC+anti-let-7 group (P < 0.05). Double luciferase activity assay showed that HMGA2 and KRAS were the targets of let-7. These findings indicate that inhibition of circPVT1 can inhibit the aging of nucleus pulposus cells. The mechanism may be through binding let-7 to inhibit the targeting of HMGA2 and KRAS proteins.

Effects of Long Non-coding RNA Plasmacytoma Variant Translocation 1 Gene on Inflammatory Response and Cell Migration in Infected Gastric Epithelial Cell Line / 中国医学科学院学报

To investigate the mechanism of long non-coding RNA plasmacytoma variant translocation 1 (PVT1) in gastric cancer caused by (HP) infection. The expression of PVT1 was detected by quantitative real-time polymerase chain reaction in HP-infected normal gastric epithelial cells GES-1. Gastric cancer cell line SGC-7901 was transfected with PVT1 small interfering RNA and co-cultured with HP,and then the inflammatory cytokines such as tumor necrosis factor-α (TNF-α),interleukin (IL) -1β,IL-6 and IL-8 were detected. After PVT1 was knocked down,the effects of PVT1 on the proliferation and migration of gastric cancer cells were examined by cell scratch assay. RNA-pulldown combined with mass spectrometry was used to detect the protein binding to PVT1,and the result of mass spectrometry was verified by RNA-pulldown combined with Western blot. In HP-infected normal gastric epithelial cells GES-1,quantitative real-time polymerase chain reaction showed that PVT1 was significantly up-regulated (=7.160,=0.019). PVT1 was knocked down in gastric cancer cells,and then infected with HP. The expressions of inflammatory factors including TNF-α (=3.899,=0.011),IL-1β (=14.610,=0.000),and IL-8 (=6.557,=0.001) were significantly inhibited. Although PVT1 knockdown had no significant effect on the proliferation ability of gastric cancer cells,it inhibited the migration of cells. PVT1 might interact with RPS8 protein. PVT1 may act as a pro-inflammatory factor and regulate gastric cancer caused by HP infection.

Expression of lncRNA PVT1 in colorectal cancer tissues and cells and its effect on chemo-sensitivity to cisplatin and the possible mechanisms / 中国肿瘤生物治疗杂志

@#Objective: To study the regulatory effects and possible mechanism of long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1) on chemotherapy sensitivity to cisplatin (DDP) of colorectal cancer (CRC)．Methods: A total of 112 pairs of matched cancer and adjacent non-cancerous tissues were obtained from the CRC patients who underwent surgical resection in the First Affiliated Hospital of Xinxiang Medical University betweenApril 2006 and March 2011.All specimens were confirmed by pathological examinations. Tumor tissues and corresponding adjacent non-cancerous tissues from 30 cisplatin-sensitive CRC patients and 30 cisplatin-resistant patients were selected. Human CRC cell lines (HT29, SW480, HCT116, RKO and LoVo) and normal colonic epithelial cell line NCM460 were also collected for this study; and DDP-resistant RKO/DDP and LoVo/DDP cell lines were constructed. siPVT1, siNC, LV-PVT1 and LV-NC were transfected into LoVo and RKO cells or LoVo/DDP and RKO/DDP cells using lipofectamineTM2000. The expression of lncRNA PVT1 in CRC tissues and cells was tested by Real-time qPCR. CCK-8 assay, flow cytometry and WB were performed to test the effect of PTV1 knockout or enforcement on cell proliferation, apoptosis and expressions of apoptosis-related proteins, respectively. The CRC subcutaneous transplanted xenograft model was established on athymic nude mice to study the effect of PVT1 over-expression on tumor growth and DDP resistance. Results: PVT1 was highly expressed in the cancer tissues and CRC cells, and its expression was positively associated with cisplatin resistance of CRC. After knockdown of PVT1, the proliferation of cisplatinresistant CRC cells was significantly suppressed, while the apoptosis was significantly enhanced (P<0.05 or P<0.01); Mechanically, the levels of drug resistance-associated molecules, including MDR1 and MRP1, as well as the expression of anti-apoptotic Bcl-2 were significantly downregulated whereas the levels of pro-apoptotic Bax and cleaved caspase-3 were increased in PVT1-silenced DDP-resistant CRC cells. Over-expression of PVT1 reversely increased proliferation and decreased apoptosis of CRC cells (P<0.05 or P<0.01). In addition, PVT1 over-expression in CRC cells significantly promoted DDP-resistance in vivo (P<0.05). Conclusion: Collectively, knockdown of PVT1 expression can significantly suppress cell proliferation and promote apoptosis of DDP-resistant CRC cells. Overexpression of PVT1 can significantly promote the growth of CRC cells in vitro and transplanted xenograft in vivo. PVT1 regulates endogenous apoptosis pathways and further promotes the sensitivity of CRC cells to cisplatin chemotherapy via inhibiting the expressions of MDR1 and MRP1.

Plasmacytoma variant translocation 1 in cancer / 国际肿瘤学杂志

Plasmacytoma variant translocation1 (PVT1) is a very important long nocoding RNA,which located at chromosome 8q24.21 in human beings.Aberrant expression and polymorphism of PVT1 was closely associated with various kinds of cancers such as malignant lymphoma,breast cancer,colorectal cancer,pancreatic cancer,and affected survival and prognosis of cancer patients.This mainly attribute to its interactin with myc,miRNAs and other proteins,and also gene polymorphism.Further study of PVT1 is expected to provide a new target for the diagnosis and treatment of cancer.