Circular RNA ERBB2 Contributes to Proliferation and Migration of Airway Smooth Muscle Cells via miR-98-5p/IGF1R Signaling in Asthma.

BACKGROUND: Asthma belongs to chronic inflammatory respiratory diseases characterized by airway inflammation and remodeling. Circular RNAs (circRNAs) are promising therapeutic targets for various diseases, including asthma. In this work, we aim to investigate the role of circular RNA Erb-B2 receptor tyrosine kinase 2 (circERBB2) during progression of asthma. METHODS: Human airway smooth muscle cells (ASMCs) were treated with platelet-derived growth factor BB (PDGF-BB) to mimic cell remodeling. The expression of circERBB2, microRNA-98-5p (miR-98-5p), and insulin-like growth factor 1 receptor (IGF1R) was measured by qRT-PCR. Cell proliferation, migration and apoptosis were determined by cell counting-8 (CCK-8), transwell, and flow cytometry. Protein levels of PCNA, MMP-9, IGF1R were evaluated using Western blotting. The levels of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and IL-6 were detected by enzyme-linked immunosorbent assay (ELISA). Luciferase reporter gene experiment was adopted to evaluate the targeting relationship between miR-98-5p with circERBB2 and IGF1R. Interaction between RNAs was determined by RNA pulldown and RIP assay. RESULTS: The depletion of circERBB2 attenuated the proliferation, migration, and levels of inflammatory factors induced by PDGF-BB and cell apoptosis. CircERBB2 was identified to directly interact with miR-98-5p, and overexpression of miR-98-5p abolished the function of circERBB2 on PDGF-BB-stimulated ASMCs. IGF1R was identified as a target of miR-98-5p, and knockdown of IGF1R relieved the PDGF-BB-induced ASMCs proliferation and migration. CONCLUSION: Our work disclosed that knockdown of circERBB2 suppressed PDGF-BB-caused proliferation, migration and inflammatory response of ASMCs, through regulating miR-98-5p/IGF1R signaling, presented circERBB2 as a promising therapeutic target for asthma.

[Effects of arsenic trioxide combined with bortezomib on proliferation and apoptosis of K562 cells and their mechanism].

This study was aimed to investigate the effect of arsenic trioxide (As(2)O(3)) alone and in combination with bortezomib (Bor) on proliferation and apoptosis of leukemia cell line K562, and to analyze the potential mechanism. K562 cells were treated with different concentrations of As(2)O(3) or Bor (alone or combination) for 24, 48 h. MTT method was used to detect the cell proliferation. After K562 cells were treated with 0.5 µmol/L As(2)O(3) alone or in combination with 10 nmoL/L Bor, the apoptosis rate and cell cycle were measured by flow cytometry, and the activity of NF-κB was analyzed by SP immunohistochemistry. The results indicated that the different concentrations of As(2)O(3) and Bor could inhibit the K562 cell proliferation in a time- and dose-dependent manners (P < 0.05). The IC(50) of Bor and As(2)O(3) in 48 h were 20 nmol/L and 0.6 µmol/L respectively. When K562 cells were treated with As(2)O(3) or Bor alone for 24 h, the apoptotic rate of K562 cells increased, and the apoptotic rate in combination group was higher than that in As(2)O(3) or Bor group. The cells were apparently arrested in G(2)/M phase in Bor group and G(0)/G(1) phase in As(2)O(3) group. The activity of NF-κB decreased significantly in As(2)O(3) or Bor group (P < 0.05), this effect was most significant in the combination group (P < 0.01). It is concluded that both As(2)O(3) and Bor can inhibit the proliferation and induce apoptosis of K562 cells, a synergistic effect can be observed when a low dose of As(2)O(3) combined with low dose of Bor. The different cell cycle block site and the decrease of activity of NF-κB may be one of the mechanisms underlying their synergic effect.

[Effects of hyperbaric oxygenation combined with As(2)O(3) on proliferation of K562 cells and associated mechanism].

This study was aimed to explore the effects of hyperbaric oxygenation (HBO) alone or combined with As(2)O(3) on proliferation, apoptosis and expression of HIF-1a, VEGF, caspase-3 mRNA of K562 cells, and the molecular mechanism of As(2)O(3) enhancing the anti-leukemic effect of HBO so as to provide a scientific basis for clinical treatment of chronic myeloid leukemia. The effects of drugs on proliferation of K562 cells was assayed by MTT method, the apoptosis rate of K562 cells was detected by flow cytometry with Annexin V/PI double staining, the expressions of HIF-1a, VEGF, caspase-3 mRNA of K562 cells were determined by real-time quantitative PCR. The results showed that as compared with As(2)O(3) alone, HBO combined with As(2)O(3) could increase inhibitory rate of K562 cell proliferation, and enhance apoptotic effect, obviously down-regulate expressions of HIF-1a and VEGF mRNA, up-regulate expression of caspase-3 mRNA. The effect of HBO combined with As(2)O(3) was higher then effect of As(2)O(3) alone, and their effects were synergistic (P < 0.05). It is concluded that HBO combined with As(2)O(3) can increase the expression of caspase 3 mRNA and decrease the expression of HIF-1a and VEGF mRNA, which may be one of molecular mechanisms underlying their synergistic antileukemia efficacy.