Peroxiredoxin 1 silencing inhibited the growth and promoted apoptosis of pancreatic cancer cells via targeting FOXO3 gene

The beginning of GPX2 and 30 years later

We published the first paper to characterize GPX2 (aka GSHPx-GI) as a selenoenzyme with glutathione peroxidase activity in 1993. Among the four Se-GPX isozymes, GPX1-4, GPX1 and GPX2 are closely related in terms of structure, substrate specificities, and subcellular localization. What sets them apart are distinct patterns of gene regulation, tissue distribution and response to selenium. While we identified the digestive tract epithelium as the main site of GPX2 expression, later work has shown GPX2 is found more widely in epithelial tissues with concentration of expression in stem cell and proliferative compartments. GPX2 expression is regulated over a wide range of levels by many pathways, including NRF2, WNT, p53, RARE and this often results in attaching undue significance to GPX2 as GPX2 is only a part of a system of hydroperoxidase activities, including GPX1, peroxiredoxins and catalase. These other activities may play equal or greater roles, particularly in cell lines cultured without selenium supplementation and often with very low GPX2 levels. This could be assessed by examining levels of mRNA and protein among these various peroxidases at the outset of studies. As an example, it was found that GPX1 responds to the absence of GPX2 in mouse ileum and colon epithelium with higher expression. As such, both Gpx1 and Gpx2 had to be knocked out in mice to produce ileocolitis. However, we note that the actual role of GPX1 and GPX2 in relation to peroxiredoxin function is unclear. There may be an interdependence that requires only low amounts of GPX1 and/or GPX2 in a supporting role to maintain proper peroxiredoxin function. GPX2 levels may be prognostic for cancer progression in colon, breast, prostate and liver, however, there is no consistent trend for higher or lower levels to be favorable.

Structure-based analysis and rational design of human peroxiredoxin-1's C-terminus-derived peptides to target sulfiredoxin-1 in pancreatic cancer

Human peroxiredoxin (PRX) family of antioxidant enzymes reduces hydrogen peroxide and alkyl hydroperoxide involved in the redox signaling, among which the widely documented PRX1 is a versatile molecule regulating cell growth, differentiation and apoptosis, and has been implicated in the tumorigensis of pancreatic cancer. In this study, we systematically examined the complex crystal structure of PRX1 with its cognate interacting partner sulfiredoxin-1 (SRX1) at molecular level, and found that the PRX1-SRX1 association is a typical peptide-mediated protein-protein interaction, where a 18-mer C-terminal tail (CTT) segment of PRX1 was identified to be primarily responsible for the interaction, which contributes ~80% and ~ 55% to the total binding potency of SRX1 to PRX1 monomer and homodimer, respectively. We also demonstrated that the SRX1 exhibits a strong global selectivity for PRX1 CTT tail over other PRX family proteins. Next, the intermolecular interaction between PRX1 CTT tail and SRX1 was investigated at structural, energetic and dynamic levels, from which a 9-mer core region of PRX1 CTT tail was defined as the SRX1-binding hotspot. Biophysical assays substantiated that the CTT and CTTc peptides (out of PRX1 protein context) can bind in an independent manner and possess a close affinity to SRX1. Based on the CTTc sketch a computational combinatorial library consisting of 216 designed peptide derivatives was rationally generated, from which the top-5 hits were found to have comparable affinity with CTT peptide and improved affinity relative to CTTc peptide. They can be used as structurally reduced lead molecular entities to further develop new peptidic agents for therapeutic purpose to disrupt the native PRX1-SRX1 interaction by competing with PRX1 CTT tail for the peptide-binding pocket of SRX1.

LINC00472 suppressed by ZEB1 regulates the miR-23a-3p/FOXO3/BID axis to inhibit the progression of pancreatic cancer

The tumour-suppressive role of LINC00472 has been extensively reported in various human cancers such as lung, colon and ovarian cancers, yet its function in pancreatic cancer remains unidentified. Here, the current research aimed to explore the role and regulatory axis mediated by LINC00472 in the progression of pancreatic cancer. RT-qPCR was adopted to determine LINC00472 expression in the harvested pancreatic cancer tissues and adjacent normal tissues. Loss-of-function and gain-of-function experiments were performed to examine the effects of LINC00472 on proliferation and apoptosis in vitro and tumorigenesis in vivo. Immunoblotting was performed to detect the expression of several proliferation and apoptosis-related proteins. Bioinformatic analysis, dual-luciferase reporter assay and RNA pull-down were conducted to profile the relationships between LINC00472 and miR-23a-3p, between miR-23a-3p and FOXO3 and between FOXO3 and BID. The LINC00472 expression was down-regulated by ZEB1 in the pancreatic cancer cells and tissues. LINC00472 could competitively bind to miR-23a-3p to enhance the expression of FOXO3, which consequently could promote the BID expression, thereby suppressing proliferation and promoting the apoptosis of pancreatic cancer cells. Meanwhile, the inhibitory role of LINC00472 in tumorigenesis was validated in vivo, and the LINC00472-mediated miR-23a-3p/FOXO3/BID axis was also demonstrated in the nude mouse tumour formation model. The study substantiated the antitumour activity of LINC00472 in pancreatic cancer and proposed a regulatory axis in which LINC00472 competitively binds to miR-23a-3p to enhance the FOXO3 expression and promote BID expression. Consequently, these findings provide theoretical basis for developing potential targets for the treatment of pancreatic cancer.

Role of Forkhead box O3a transcription factor in autoimmune diseases

Forkhead box O3a (FOXO3a) transcription factor, the most important member of Forkhead box O family, is closely related to cell proliferation, apoptosis, autophagy, oxidative stress and aging. The downregulation of FOXO3a has been verified to be associated with the poor prognosis, severer malignancy and chemoresistance in several human cancers. The activity of FOXO3a mainly regulated by phosphorylation of protein kinase B. FOXO3a plays a vital role in promoting the apoptosis of immune cells. FOXO3a could also modulate the activation, differentiation and function of T cells, regulate the proliferation and function of B cells, and mediate dendritic cells tolerance and immunity. FOXO3a accommodates the immune response through targeting nuclear factor kappa-B and FOXP3, as well as regulating the expression of cytokines. Besides, FOXO3a participates in intercellular interactions. FOXO3a inhibits dendritic cells from producing interleukin-6, which inhibits B-cell lymphoma-2 (BCL-2) and BCL-XL expression, thereby sparing resting T cells from apoptosis and increasing the survival of antigen-stimulated T cells. Recently, plentiful evidences further illustrated the significance of FOXO3a in the pathogenesis of autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, ankylosing spondylitis, myositis, multiple sclerosis, and systemic sclerosis. In this review, we focused on the biological function of FOXO3a and related signaling pathways regarding immune system, and summarized the potential role of FOXO3a in the pathogenesis, progress and therapeutic potential of autoimmune diseases.

KIF23 enhances cell proliferation in pancreatic ductal adenocarcinoma and is a potent therapeutic target

Background

In recent research, high expression of kinesin family member 23 (KIF23), one of the kinesin motor proteins involved in the regulation of cytokinesis, has been shown to be related to poor prognosis in glioma and paclitaxel-resistant gastric cancer, as a results of the enhancement of proliferation, migration, and invasion. In this study, we analyzed the role of KIF23 in the progression of pancreatic ductal adenocarcinoma.

Methods

A bioinformatic method was used to analyze the KIF23 mRNA level in pancreatic tumor tissues compared with normal pancreatic tissues and to analyze the connection between high KIF23 expression and prognosis. We examined the expression of KIF23 using immunohistochemistry and analyzed the connection between the expression of KIF23 and clinicopathological features in pancreatic ductal adenocarcinoma patients. In addition, a colony formation assay, MTT assay, and western blot assay were performed in vitro, along with a mouse xenograft model in vivo, to analyze the effect of KIF23 on proliferation. Further, the correlation between KIF23 and CDCA8 was analyzed by TCGA and immunohistochemical data.

Results

Bioinformatic results showed that KIF23 mRNA expression was higher in pancreatic tumor tissues than in normal pancreatic tissues and a poor prognosis has been linked to the high expression of KIF23. Immunohistochemistry revealed that KIF23 was highly expressed at the protein level and high expression of KIF23 correlated with adverse clinicopathological features. Our experimental results demonstrated that knockdown of KIF23 could inhibit the proliferation of pancreatic cells. Further, a positive correlation between KIF23 and CDCA8 expression existed, and KIF23 might promote pancreatic cancer proliferation by affecting CDCA8 expression.

Conclusions

Our data showed that high expression of KIF23 is associated with a poor prognosis, and KIF23 might be a potential therapeutic target for pancreatic ductal adenocarcinoma.

microRNA-582 Potentiates Liver and Lung Metastasis of Gastric Carcinoma Cells Through the FOXO3-Mediated PI3K/Akt/Snail Pathway

Background

The dysregulation of microRNA (miRNAs) is broadly participated in cancer progression, resulting in sustained cell proliferation by directly targeting various targets. This study investigated the expression of miR-582 in GC and its association with liver metastasis.

Methods

Firstly, differentially expressed miRNAs in gastric cancer (GC) tissues were predicted by microarray. Then, the relationship between miR-582 and clinical characteristics of GC patients was analyzed. By silencing of miR-582 in GC cells, the change in malignant biological behaviors of GC cells was detected. The upstream lncRNA, downstream targeting genes of miR-582 and the corresponding signaling pathway were predicted by online databases and verified by luciferase reporter assays, RT-qPCR and Western blot analysis. Finally, the effects of miR-582 on the growth and metastasis of GC cells were detected by in vivo tumorigenesis and metastasis tests.

Results

MiR-582 was highly expressed in GC tissues and related to the metastasis of patients with GC. Silencing of miR-582 expression blocked malignant biological behaviors of GC cells in vitro and in vivo. MiR-582 inhibited forkhead box protein O3 (FOXO3) to upregulate the PI3K/AKT/Snail signaling pathway in GC cells. Besides, GATA6-AS1 was found as an upstream lncRNA to modulate the expression of miR-582.

Conclusion

MiR-582 induced by GATA6-AS1 silencing promotes the growth and metastasis of GC cells by targeting FOXO3 to induce the activation of the PI3K/AKT/Snail signaling pathway. MiR-582 could be a potential molecular therapy target for patients with GC.

Peroxiredoxin 1 as an inflammatory marker in diarrhea-predominant and postinfectious irritable bowel syndrome

BACKGROUND

Low-grade inflammation occurs in some patients with irritable bowel syndrome (IBS). However, the exact inflammatory markers of IBS and the relationship of these markers with IBS subtypes and symptoms are poorly defined. Peroxiredoxin 1 (PRDX1) plays an important role in inflammatory responses, including intestinal inflammation. We investigated whether PRDX1 is associated with the diagnosis, subtypes, and symptom severity of IBS.

METHODS

A total of 177 IBS patients and 174 sex- and age-matched healthy controls (HCs) were recruited. The PRDX1 levels in the sera and colonic mucosa of the participants were detected by enzyme-linked immunosorbent assays and immunohistochemistry. The severity of IBS symptoms was assessed using the IBS Severity Scoring System (SSS) questionnaire.

RESULTS

The PRDX1 levels in the sera (F = 71.81, P < .001) and colonic mucosa (F = 5.359, P < .001) of postinfectious (PI-IBS) and diarrhea-predominant IBS (IBS-D) groups were significantly higher than those of the other three IBS subtypes and HC group. The PRDX1 level in the serum and colonic mucosa of IBS-D (serum, P < .01, mucosa, P < .001) and PI-IBS (serum, P < .05, mucosa, P < .001) groups with the most severe symptoms was significantly higher than that in the groups with mild and moderate symptoms. Correlation analysis revealed that in patients with IBS-D (P < .001) and PI-IBS (P < .05), the levels of PRDX1 and TNF-α in sera had a significant positive correlation with IBS-SSS.

CONCLUSION

Elevated PRDX1 in the serum and colon mucosa may be closely related to the progression of IBS (especially IBS-D and PI-IBS) and the expression of gastrointestinal symptoms.

Peroxiredoxin V Inhibits Emodin-induced Gastric Cancer Cell Apoptosis via the ROS/Bcl2 Pathway

BACKGROUND/AIM

Peroxiredoxin (Prx) protein family is aberrantly expressed in various cancers including gastric cancer. Among the six family members, Prx V has been known as an antioxidant enzyme which scavenges intracellular reactive oxygen species (ROS) and modulates cellular apoptosis. This study aimed at investigating the role of Prx V in apoptosis of gastric cancer cells.

MATERIALS AND METHODS

Stably constructed Prx V knockdown, over-expression and mock AGS cells (a human gastric adenocarcinoma cell line) were used to study the effect of Prx V on emodin-induced apoptosis by western blotting, cell viability, apoptosis and ROS detection assays.

RESULTS

Overexpression of Prx V significantly decreased emodin-induced cellular apoptosis and ROS levels compared to Mock and Prx V knockdown AGS cells. Also, overexpression of Prx V down-regulated the expression of pro-apoptotic proteins, Bad and cleaved PARP, and increased the expression of anti-apoptotic protein, Bcl2.

CONCLUSION

Prx V suppresses AGS cell apoptosis via scavenging intracellular ROS and modulating apoptosis-related markers.