Alterations of Signaling Pathways in Essential Thrombocythemia with Calreticulin Mutation

Purpose

Though mutations of the calreticulin (CALR) gene have been identified in essential thrombocythemia patients, the detailed mechanisms for CALR mutations have not been completely clarified. Our study is aimed at characterizing alteration of protein expression in ET patients with mutated CALR^del52 and further recognizing possible involvement of signaling pathways associated with CALR mutations.

Patients and Methods

Protein pathway array was performed to analyze the expression levels of proteins involved in various signaling pathways in peripheral blood neutrophils from 18 ET patients with mutated CALR^del52, 20 ET patients with JAK2^V617F mutation and 20 controls.

Results

We found 20 proteins differentially expressed in ET patients with mutated CALR^del52 compared with healthy controls. These proteins were associated with molecular mechanisms of cancer in ingenuity pathways analysis (IPA) network. We identified top ten canonical pathways which including apoptotic pathways and cellular cytokine pathways might participate in pathogenesis of ET with mutated CALR^del52. Additionally, there were 8 proteins found to be dysregulated differently between ET patients with mutated CALR^del52 and those with JAK2^V617F mutation. These proteins might be related to the unique signaling pathways activated by CALR^del52 mutation which were different to JAK/STATs pathway by JAK2^V617F mutation.

Conclusion

Our study demonstrated that numerous alterations of signaling proteins and pathways in ET patients with mutated CALR^del52. These findings could help to gain insights into the pathological mechanisms of ET.

BI2536, a potent and selective inhibitor of polo-like kinase 1, in combination with cisplatin exerts synergistic effects on gastric cancer cells

BI2536 is a highly selective and potent inhibitor of polo-like kinase 1 (PLK1). In this study, we aimed to determine whether BI2536 and cisplatin can synergistically inhibit the malignant behavior of gastric cancer cells. For this purpose, the expression of PLK1 in gastric cancer cells was determined. The effects of BI2536, cisplatin, and the combination of BI2536 and cisplatin on gastric cancer cell viability, invasion, cell cycle arrest and apoptosis were assessed. Furthermore, the expression of cell cycle-regulated proteins was examined. Moreover, the differentially expressed proteins between the SGC-7901 and SGC-7901/DDP (cisplatin-resistant) cells, and the enriched signaling pathways were analyzed by protein pathway array following treatment with BI2536 (IC50) for 48 h. Our results revealed that PLK1 was upregulated in the SGC-7901/DDP (cisplatin-resistant) gastric cancer cells compared with the SGC-7901 cells. BI2536 enhanced the inhibitory effect of cisplatin on SGC-7901 cell viability and invasion. BI2536 induced G2/M arrest in SGC-7901 and SGC-7901/DDP cells. BI2536 promoted cisplatin-induced gastric cancer SGC-7901/DDP cell apoptosis. It also induced the differential expression of 68 proteins between the SGC-7901 and SGC-7901/DDP cells, and these differentially expressed proteins were involved in a number of cellular functions and signaling pathways, such as cell death, cell development, tumorigenesis, the cell cycle, DNA duplication/recombination/repair, cellular movement, and the Wnt/β-catenin and mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK)/ribosomal S6 kinase 1 (RSK1) signaling pathways. On the whole, our findings suggest that BI2536 and cisplatin synergistically inhibit the malignant behavior of SGC-7901/DDP (cisplatin‑resistant) gastric cancer cells.

Protein marker profiling in different T classification in laryngeal squamous cell carcinoma

BACKGROUND

The identification of specific biomarkers related to laryngeal squamous cell carcinoma (SCC) will be helpful in early detection and determination of reasonable treatment options, which are crucial for the prognosis of patients with laryngeal SCC. The purpose of this study was to profile the protein markers that can be used for diagnosis and prognosis of laryngeal SCC and to observe laryngeal SCC progression with distinct stages of malignant transformation.

METHODS

Two hundred twenty-five proteins were tested in 84 pairs of tumors and adjacent nontumor mucosa samples using protein pathway arrays (PPAs). Ingenuity pathway analysis (IPA) enrichment analysis was performed and protein expression profiles in different T classification were mapped by grid analysis of time-series expression (GATE).

RESULTS

Among 16 proteins differently expressed between tumors and normal tissues, we selected 9 proteins (TTF-1, CDK2, Eg5, proliferating cell nuclear antigen [PCNA], Bcl-xL, 14-3-3β, p27, SRC-1, cytokeratin 18) as markers for classification. From the IPA analysis, we observed a more malignant transformation from T3 to T4 at the protein level and described the changing patterns of the proteins' expression in this progression. JAK2, keratin 10, and IL-3Rα were identified as markers for prognosis. The risk model based on histological grade, T classification, N classification, JAK2, and IL-3Rα can predict the prognosis with 85.5% accuracy.

CONCLUSION

This study indicated that dysregulated signaling proteins can be selected as useful biomarkers for tumor classification and predicting the outcome in patients with laryngeal SCC. The changing patterns of the proteins' expression in different stages were related to the more malignant transformation and further studies will focus on the role of these proteins in laryngeal SCC progression.

Elevated cell proliferation and VEGF production by high-glucose conditions in Müller cells involve XIAP

PURPOSE

Müller cells have important roles in the pathogenesis of diabetic retinopathy by promoting cell proliferation and inducing the production of vascular endothelial growth factor (VEGF) under hyperglycemic conditions. The objective of this study was to determine the potential mechanism of Müller cell proliferation and VEGF production due to high-glucose conditions.

METHODS

Primary cultured rat Müller cells were incubated with medium containing variable concentrations of glucose and/or embelin, a specific inhibitor of X-linked inhibitor of apoptosis protein (XIAP), for 72 h. The proliferation of Müller cells was assessed by the MTT assay. The expression and/or phosphorylation of 146 proteins were assessed using protein pathway array.

RESULTS

High concentrations of glucose-induced Müller cell proliferation and altered expression and/or phosphorylation of 47 proteins that have been identified to have key roles in several important signaling pathways (XIAP, VEGF, HIF1α, NFκB, etc) and are involved in the regulation of cell survival, proliferation, or apoptosis. However, Müller cell alterations induced by high-glucose conditions were counteracted by the XIAP inhibitor embelin, and 26 proteins/phosphorylations (out of 47) were restored to their normal levels. Nine proteins, including NFκB p65, p-p38, tumor necrosis factor-α, urokinase-type plasminogen activator, CREB, IL-1β, HCAM, estrogen receptor-α, and p-Stat3, were involved in regulatory networks between XIAP and VEGF.

CONCLUSIONS

The current study suggests that XIAP may be a potential regulator that can mediate a series of pathological changes induced by high-glucose conditions in Müller cells. Therefore, embelin could be a potential agent for the prevention and treatment of diabetic retinopathy.