Recombinant Anti-Mouse IgG Antibody [RM104] (A121355)

In ovarian clear cell carcinoma (OCCC), the mutation rate of the AT-rich interaction domain 1A (ARID1A) gene is 46-57%. However, the effects of ARID1A gene silencing by small interfering RNA (siRNA) on the sensitivity of OCCC to cisplatin have not been investigated. Thus, this study aimed to elucidate the association between ARID1A gene silencing and drug resistance in OCCC. Three pairs of ARID1A gene siRNA fragments (siRNA-1, siRNA-2 and siRNA-3) were designed and transiently transfected into ES2 OCCC cells using RNAi Max reagent. Western blotting results demonstrated that the transfection reduced ARID1A protein expression levels, with the siRNA-3 group having the lowest levels. The IC₅₀ value, determined using a Cell Counting kit-8 assay, was significantly increased by siRNA-3 transfection compared with that in blank control and negative control groups. The cell survival rate following treatment with 50 µM cisplatin for 48 h was significantly increased in the siRNA-3 group compared with the blank control and negative control groups. Flow cytometric analysis revealed that the apoptosis rate for cisplatin-treated cells was significantly lower in cells with siRNA-3 transfection than in those without, and the apoptosis rate in siRNA-3-transfected cells was lower than that in the negative control group. Western blot analysis showed that the expression level of AKT in cisplatin-treated cells was significantly decreased compared with that in the negative control group, and the AKT expression level in cisplatin-treated cells was significantly higher with siRNA-3 transfection than without. Therefore, the results demonstrated that ARID1A siRNA efficiently decreased ARID1A expression, which reduced cisplatin chemosensitivity and cell apoptosis in ES2 OCCC cells via the regulation of AKT expression.

Myocardial ischemia/reperfusion (I/R) injury may cause the apoptosis of cardiomyocytes as well as cardiac fibrosis, which is characterized as the transdifferentiation of fibroblasts to myofibroblasts and collagen deposition. MicroRNAs (miRNAs or miRs) have been demonstrated to be involved in myocardial I/R injury. However, the underlying molecular mechanism remains largely unclear. In the present study, mouse cardiomyocyte M6200 cells were treated with hypoxia/reoxygenation (H/R). Our data indicated that H/R treatment led to cell apoptosis, the increased expression of fibrosis‑related proteins, namely collagen I, II, III, and fibronectin, as well as the downregulation of miR-142-3p in M6200 cells. Overexpression of miR-142-3p suppressed the H/R-induced apoptosis and fibrosis of M6200 cells. Bioinformatics analysis and a Dual‑Luciferase reporter assay further identified high mobility group box 1 (HMGB1) as a direct target gene of miR-142-3p, and miR-142-3p negatively regulated the protein level of HMGB1 in M6200 cells. Furthermore, knockdown of HMGB1 enhanced cell proliferation whereas it inhibited the apoptosis and fibrosis of M6200 cells. In addition, TGF-β1/Smad3 signaling was suggested to be involved in the miR-142-3p/HMGB1-mediated apoptosis and fibrosis of M6200 cells treated with H/R. Taken together, the findings of the present study demonstrate that miR-142-3p inhibits H/R-induced apoptosis and fibrosis of cardiomyocytes, partly at least, by the direct inhibition of HMGB1 expression. Therefore, these findings have increased our understanding of the pathogenesis of H/R-induced myocardial injury.

MicroRNAs (miRs) may induce mRNA degradation or inhibit protein translation by directly binding to the 3'-untranslational region of target mRNAs. It has been reported that miR-138 is downregulated in malignant melanoma (MM) cells. However, the role of miR-138 in MM cell proliferation, invasion and energy metabolism remains unknown. These were investigated using reverse transcription-quantitative polymerase chain reaction was used to evaluate the expression of miR-138 and the mRNA expression of hypoxia-inducible factor-1a (HIF-1a), as HIF-1a serves a crucial role in glycolysis, which is important for tumor growth. In addition, western blot analysis was used to detected the protein expression of HIF-1a, while MTT and Transwell assays evaluated cell proliferation and invasion, respectively. Furthermore, glucose consumption and lactic acid production were assessed. These tests were conducted using the normal human melanocyte cell line HM and the MM cell line WM451, which was transfected variously with scramble miR mimics, miR-138 mimics, miR-138 inhibitor, non-specific small interfering (si)RNA, HIF-1a siRNA, or co-transfected with miR-138 mimics and pc-DNA3.1(+)-HIF-1a plasmid. The results showed that miR-138 was significantly downregulated in MM WM451 cells compared to a normal melanocyte cell line HM. Overexpression of miR-138 significantly inhibited the proliferation and invasion of WM451 cells. These effects were similar to those induced by the siRNA-mediated knockdown of HIF-1a, a direct target of miR-138. Further investigation found that miR-138 negatively regulated the protein expression of HIF-1a in WM451 cells. Moreover, upregulation of miR-138 notably inhibited the glycolysis level, as demonstrated by reduced glucose consumption and lactic acid production, which could be reversed by the overexpression of HIF-1a. In summary, the present study demonstrated that miR-138 is able to inhibit proliferation, invasion and glycolysis in MM cells, potentially by directly targeting HIF-1a.