LncRNA SND1-IT1 accelerates the proliferation and migration of osteosarcoma via sponging miRNA-665 to upregulate POU2F1

OBJECTIVE

To clarify the role of long non-coding RNA (lncRNA) SND1-IT1 in accelerating the proliferative and migratory abilities of osteosarcoma (OS) via sponging miRNA-665 to upregulate POU2F1.

PATIENTS AND METHODS

The relative level of SND1-IT1 in OS tissues was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The target gene of SND1-IT1 was predicted by bioinformatics and verified by Dual-Luciferase reporter gene assay. Similarly, the target gene of miRNA-665 was identified. Correlation among SND1-IT1, miRNA-665 and POU2F1 was evaluated through linear regression test. Regulatory effects of SND1-IT1/miRNA-665/POU2F1 on cellular behaviors of MG63 and U2OS cells were evaluated.

RESULTS

SND1-IT1 was upregulated in OS, knockdown of which attenuated proliferative and migratory abilities of OS cells. MiRNA-665 was the target gene of SND1-IT1, which was negatively correlated to SND1-IT1 in OS. POU2F1 was the target gene of miRNA-665. Its level was negatively regulated by miRNA-665 and positively regulated by SND1-IT1. Inhibited proliferative and migratory abilities of OS cells with SND1-IT1 knockdown were partially elevated by transfection of miRNA-665 inhibitor, and further downregulated by POU2F1 knockdown.

CONCLUSIONS

LncRNA SND1-IT1 accelerates proliferative and migratory abilities of OS via sponging miRNA-665 to upregulate POU2F1, thus stimulating the progression of OS.

[Changes of the release of atrial natriuretic factor (ANF) and its gene transcription in morphine tolerance rat atrium]

Specific radioimmunoassay and molecular hybridization technique were used in the present work. Compared with the control rats, we found for the first time a significant decrease of ANF in plasma and a marked increase of ANF in atria in morphine tolerant rats. Simultaneously a raised level of ANF messenger RNA in morphine tolerant rat atria was observed. It is suggested that the biosynthesis and storage of ANF in atria be increased and its release from atria decreased in morphine tolerant rats.

Calcitonin gene-related peptide in the pathogenesis and treatment of hypertension

The present study demonstrated that the plasma calcitonin gene-related peptide (CGRP) concentration was lower but the CGRP content of abdominal aorta was higher in spontaneously hypertensive rats (SHR) than in normotensive rats (WKY), using specific CGRP radioimmunoassay (P less than 0.01). In eighteen patients with essential hypertension, the concentration of plasma CGRP was also much lower than that of normal subjects, suggesting that a decreased release of arterial CGRP might be a part of the pathogenesis of essential hypertension. In SHR, a significant decrease in blood pressure was found following intravenous injection of 2.5 micrograms/kg of CGRP; similarly, in seven patients with essential hypertension intravenous injection of CGRP (50 micrograms) could induce a significant hypotensive effect. These data suggest that CGRP is a new potential drug for the treatment of essential hypertension.

[Dynorphin and atriopeptin may be involved in the depressor mechanism of clonidine]

Intravenous injection (iv) of clonidine significantly induced depressor and bradycardiac responses in rats. These responses were found to be blocked by iv alpha-adrenoreceptor blocker phentolamine, intraperitoneous injection (ip) of naloxone (10mg/kg) or iv antidynorphin-IgG(80 microliters). Furthermore, clonidine (iv) induced a significant increase of urine volume, which was also partly blocked by naloxone (10mg/kg). A dramatic increase of rat plasma immunoreactive atriopeptin induced by clonidine (iv) was partly antagonised by pretreatment with naloxone (4mg/kg) or phentolamine (10mg/kg). These results show that dynorphin and atriopeptin may be involved in the depressor mechanism of clonidine.

[The distribution, characteristics and effects of ir-BNP in central and peripheral tissues in rat]

The present study first investigated the distribution, biochemical characteristics, receptor binding and biological effects of immunoreactive brain natriuretic peptide (ir-BNP), in the central nervous system and some peripheral tissues in rats, using highly specific radioimmunoassay, radioreceptor assay and immunohistochemical method. The results suggest that BNP may be a novel neurotransmitter or circulatory hormone, which is widely distributed in various tissues and involved in the regulation of water electrolyte balance and cardiovascular activity.

[Distribution of substance K in the rat heart and its cardiovascular effects]

The present work was to investigate the distribution of Substance K (SK) in the rat heart and its cardiovascular effects. The content of SK-like immunoreactive material (SKLI), determined by using specific radioimmunoassay, was higher in the atrium (19.9 +/- 3.5 pmol/g tissue) than in the ventricle (4.1 +/- 0.8 pmol/g tissue). SKLI in the heart existed in the nerves fibers and its molecular form was identical with synthetic SK. There were high affinity binding sites of SK on the cardiohybricyte CP 8401: KD = 0.161 nmol/L, Bmax = 8.08 pmol/L. SK stimulated the release of ANF from the cardiohybricytes and from the isolated rat atria. Furthermore, SK injected intravenously induced a hypotensive effect in rats, and decreased left ventricle end systolic pressure (LVESP), +/- LVdp/dtmax, as well as slightly increased heart rate (HR). In isolated Langendorff perfusion heart of rat, SK increased HR, LVdp/dtmax, left ventricle peak systolic pressure (LVPSP) and perfusion pressure (PP). These effects of SK were inhibited by a tachykinin receptor antagonist, (D-Pro2, D-Trp7.9)-SP. These findings suggest that SK exist in the heart and might be able to bind with its specific binding sites on the cardiocytes, thus inducing the release of ANF from the atrium and regulating cardiovascular functions.

Calcitonin gene-related peptide (CGRP) in normotensive and spontaneously hypertensive rats

With the techniques of specific radioimmunoassay and gel filtration it was found that CGRP was distributed in various tissues of normotensive (WKY) and spontaneously hypertensive rats (SHR) with the highest concentration in the lumbar spinal cord (1197 +/- 94.8 pg/mg tissue) and the lowest in the auricle (15.0 +/- 2.1 pg/mg tissue). In comparison with WKY, CGRP concentration in the plasma was decreased and in the abdominal aorta and hypothalamus was increased in SHR. Gel filtration revealed only one major CGRP molecular form in the tissues. In addition, CGRP reduced the mean arterial pressure (MAP) in SHR in a dose-dependent manner. These data suggest that CGRP may play an important role in the pathogenesis of hypertension and its possible therapy.

Synthesis of the leu-enkephalin gene

The synthesis of Leu-enkephalin gene by an alternative approach was described in this paper. The sequence of the synthetic gene, 26 base-pairs in length, was derived from the amino acid sequence of the hormone peptide Leu-enkephalin. It bears single-stranded cohesive termini for the restriction endonucleases EcoR I and BamH I so that it may be inserted into a pBR 322 plasmid. The 4 deoxyoligonucleotide fragments, varying in length from octanucleotide to octadecanucleotide, were synthesized by an improved phosphotriester method developed in our laboratory. All chemically synthetic fragments were pure and had the correct sequences. The assembly of the Leu-enkephalin gene was carried out in a one-step ligation reaction catalysed by T4-DNA ligase with good yield. Finally, the purified products from polyacrylamide gel electrophoresis had the correct joining-points as predicted.