Polymorphisms in PRKCDBP, a Transcriptional Target of TNF-α, Are Associated With Inflammatory Bowel Disease in Korean

Low expression of PRKCDBP promoted cisplatin resistance in lung adenocarcinoma by DNMT1 and TNF‑α

The aim of the present study was to explore the mechanism of protein kinase C delta binding protein (PRKCDBP) promoting cisplatin resistance in lung adenocarcinoma (LAD). The PRKCDBP expression level was herein detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We overexpressed PRKCDBP and tumor necrosis factor-α (TNF-α) in A549/DDP cell line, DNMT1 in A549 cells and siRNA TNF-α in A549 cells with lentivirus-mediated technique, and then, analyzed their biological diversification. The results showed a significantly lower expression level of PRKCDBP was lowly expressed in the A549/DDP cell line and LAD tissues than that in A549 cells and adjacent cancer tissues (P<0.05 and P<0.01), while the DNMT1 mRNA level was remarkably increased (P=0.000) and the promoter of PRKCDBP was hypermethylated in the A549/DDP cell line. Additionally, DNMT1 mRNA level in cisplatin-insensitive group was markedly higher than that in cisplatin-sensitive group (t=7.233, P<0.0001), while PRKCDBP mRNA level in cisplatin insensitive group was notably lower than that in cisplatin-sensitive group (t=8.784, P<0.0001). The results showed that PRKCDBP mRNA level was significantly elevated following treatment with 5 µM decitabine for 24 h (P<0.0001), while the DNMT1 mRNA level was notably reduced (P=0.000). When PRKCDBP was overexpressed, the DNMT1 mRNA level was markedly decreased (P=0.007), the rate of proliferation (P<0.05 or P<0.01), IC50 of cisplatin (P<0.001), G2/M phase and S phase cells were obviously reduced (P<0.001), while G0/G1 phase cells, apoptosis (P<0.001) distinctly increased, but migration ability did not significantly change. TNF-α overexpression resulted in an increase of PRKCDBP mRNA level (P<0.001), while TNF-α siRNA led to PRKCDBP mRNA level distinctly reduced (P<0.001). Overexpression of DNMT1 improved IC50 in A549 cells. Thus, findings of the present study ascertained the promoter of PRKCDBP was hypermethylated in A549/DDP cells. In conclusion, low expression of PRKCDBP promoted cisplatin resistance in LAD by DNMT1 and TNF-α.

IL-32 gamma reduces lung tumor development through upregulation of TIMP-3 overexpression and hypomethylation

The low expression of tissue inhibitor of metalloproteinase 3 (TIMP-3) is important in inflammatory responses. Therefore, inhibition of TIMP-3 may promote tumor development. Our study showed that expression of TIMP-3 was elevated in lL-32γ mice lung tissues. In this study, we investigated whether IL-32γ mice inhibited lung tumor development through overexpression of TIMP-3 and its methylation. To explore the possible underlying mechanism, lung cancer cells were transfected with IL-32γ cDNA plasmid. A marked increase in TIMP-3 expression was caused by promoter methylation. Mechanistic studies indicated that TIMP-3 overexpression reduced NF-κB activity, which led to cell growth inhibition in IL-32γ transfected lung cancer cells. We also showed that IL-32γ inhibits expression of DNA (cytosine-5-)-methyltransferase 1 (DNMT1). Moreover, IL-32γ inhibits the binding of DNMT1 to TIMP-3 promoter, but this effect was reversed by the treatment of DNA methyltransferase inhibitor (5-Aza-CdR) and NF-κB inhibitor (PS1145), suggesting that a marked increase in TIMP-3 expression was caused by inhibition of promoter hypermethylation via decreased DNMT1 expression through the NF-κB pathway. In an in vivo carcinogen induced lung tumor model, tumor growth was inhibited in IL-32γ overexpressed mice with elevated TIMP-3 expression and hypomethylation accompanied with reduced NF-κB activity. Moreover, in the lung cancer patient tissue, the expression of IL-32 and TIMP-3 was dramatically decreased at a grade-dependent manner compared to normal lung tissue. In summary, IL-32γ may increase TIMP-3 expression via hypomethylation through inactivation of NF-κB activity, and thereby reduce lung tumor growth.

The Correlation of Serum IL-12B Expression With Disease Activity in Patients With Inflammatory Bowel Disease

Genetic variants in IL12B, encoding the p40 subunit common in interleukin-12 (IL-12) and interleukin-23, were identified as the susceptibility loci for inflammatory bowel disease (IBD). This study aimed to identify the correlation of serum IL-12B expression with disease activity in patients with IBD and evaluate the possibility of IL-12B as a biomarker for assessing inflammatory status in IBD.A total of 102 patients with IBD, including 38, 32, and 32 patients with Crohn's disease (CD), ulcerative colitis (UC), and intestinal Behçet's disease (intestinal BD), respectively, were included. The clinical and laboratory data from the patients were collected at the time of serum IL-12B measurement. Serum IL-12B levels were measured using an enzyme-linked immunosorbent assay.The median IL-12B levels in patients with CD, UC, and intestinal BD were significantly higher than those in controls (1.87, 2.74, and 2.73 pg/mL, respectively, vs. 1.42 pg/mL, all P <0.05). IL-12B concentrations were associated with disease activity in patients with UC and intestinal BD but not in those with CD. IL-12B levels were increased with increasing disease activity in patients with UC (P <0.001). Likewise, patients with active intestinal BD had higher IL-12B levels than those without active disease (P = 0.008). IL-12B levels were correlated with the endoscopic disease activity of UC (P = 0.002) and intestinal BD (P = 0.001) but not that of CD.Serum IL-12B levels were significantly correlated with clinical and endoscopic disease activity in patients with UC and intestinal BD, suggesting its potential use as a biomarker for assessing disease activity in these patients.