TNF-α up-regulates cellular inhibitor of apoptosis protein 2 (c-IAP2) via c-Jun N-terminal kinase (JNK) pathway in nasopharyngeal carcinoma

Proteasome activation is critical for cell death induced by inhibitors of polo-like kinase 1 (PLK1) in multiple cancers

Inhibitors of polo-like kinase (PLK) are currently being evaluated as anticancer drugs. However, the molecular mechanism of PLK inhibitor-induced cell death is not fully understood. In this study, we found that GW843682X and BI2536, two inhibitors of PLK1, significantly induced cell death in multiple type cells. The induction of cell death was related to the preferring expression of PLK1. However, in human umbilical vascular endothelial cells (HUVEC) and human colorectal carcinoma cells, which expressed higher levels of both PLK1 and PLK2, PLK1 inhibitors induced very low levels of cell death. Clinical analysis reveals PLK1 presence in 26 of 30 NPC tumor tissues. In in vivo NPC lung metastasis nude mouse models, PLK1 inhibitors decreased NPC progress. Mechanistically, the PLK1 inhibitor did not activate p53, and the cell death was not reversed by p53 inhibition. Moreover, PLK1 inhibitor-induced cell death was PARP- and caspase-independent. Although PLK1 inhibitors induced down-regulation of calpain inhibitor calpastatin and calpain was activated by PLK1 inhibition, calpain blocking did not reverse cell death induced by PLK1 inhibitors, suggesting the non-involvement of calpain. Surprisingly, we found that PLK1 inhibitors induced the activation of proteasome, and the treatment of cells with PLK1 inhibitors reduced the levels of ubiquitinated proteins. And proteasome inhibitors reversed cell death induced by PLK1 inhibitors in various cell types in which PLK1 was preferentially expressed. Moreover, PLK1 inhibition reversed the degradation of proteins including p53, caspase 8, PARP and calpastatin. These results suggest that the activation of proteasome is critical for cell death induced by PLK1 inhibition.

Adiponectin Suppresses Metastasis of Nasopharyngeal Carcinoma through Blocking the Activation of NF-κB and STAT3 Signaling

Adiponectin is an adipocytokine with anti-inflammatory and anticancer properties. Our previous study has shown that blood adiponectin levels were inversely correlated to the risk of nasopharyngeal carcinoma (NPC), and that adiponectin could directly suppress the proliferation of NPC cells. However, the effect of adiponectin on NPC metastasis remains unknown. Here, we revealed in clinical studies that serum adiponectin level was inversely correlated with tumor stage, recurrence, and metastasis in NPC patients, and that low serum adiponectin level also correlates with poor metastasis-free survival. Coculture with recombinant adiponectin suppressed the migration and invasion of NPC cells as well as epithelial-mesenchymal transition (EMT). In addition, recombinant adiponectin dampened the activation of NF-κB and STAT3 signaling pathways induced by adipocyte-derived proinflammatory factors such as leptin, IL-6, and TNF-α. Pharmacological activation of adiponectin receptor through its specific agonist, AdipoRon, largely stalled the metastasis of NPC cells. Taken together, these findings demonstrated that adiponectin could not only regulate metabolism and inhibit cancer growth, but also suppress the metastasis of NPC. Pharmacological activation of adiponectin receptor may be a promising therapeutic strategy to stall NPC metastasis and extend patients' survival.

Functional Roles of JNK and p38 MAPK Signaling in Nasopharyngeal Carcinoma

c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) family members integrate signals that affect proliferation, differentiation, survival, and migration in a cell context- and cell type-specific way. JNK and p38 MAPK activities are found upregulated in nasopharyngeal carcinoma (NPC). Studies have shown that activation of JNK and p38 MAPK signaling can promote NPC oncogenesis by mechanisms within the cancer cells and interactions with the tumor microenvironment. They regulate multiple transcription activities and contribute to tumor-promoting processes, ranging from cell proliferation to apoptosis, inflammation, metastasis, and angiogenesis. Current literature suggests that JNK and p38 MAPK activation may exert pro-tumorigenic functions in NPC, though the underlying mechanisms are not well documented and have yet to be fully explored. Here, we aim to provide a narrative review of JNK and p38 MAPK pathways in human cancers with a primary focus on NPC. We also discuss the potential therapeutic agents that could be used to target JNK and p38 MAPK signaling in NPC, along with perspectives for future works. We aim to inspire future studies further delineating JNK and p38 MAPK signaling in NPC oncogenesis which might offer important insights for better strategies in diagnosis, prognosis, and treatment decision-making in NPC patients.

Use of bioinformatic analyses in identifying characteristic genes and mechanisms active in the progression of idiopathic thrombocytopenic purpura in individuals with different phenotypes

OBJECTIVE

To explore the mechanism underlying the progression of newly diagnosed idiopathic thrombocytopenic purpura (ITP) to its chronic or remission state using bioinformatic methods.

METHODS

GSE56232 and GSE46922 gene expression profile datasets were downloaded from Gene Expression Omnibus (GEO). Differentially expressed genes were identified and characteristic genes were screened by weighted gene co-expression network analysis. These genes were used for function enrichment analysis and construction of a protein-protein interaction network. Finally, characteristic genes were verified to determine potential molecular mechanisms underlying ITP progression.

RESULTS

We found that characteristic genes in the chronic ITP group were mainly involved in intracellular processes and ion binding, while characteristic genes in the remission ITP group were involved in intracellular processes and nuclear physiological activities. We identified a sub-network of characteristic genes, LMNA, JUN, PRKACG, SMC3, which may indicate the mechanism by which newly diagnosed ITP progresses to chronic. Although no meaningful signaling pathways were found, the expression of NR3C1, TPR, SMC4, PANBP2, CHD1, and U2SURP may affect ITP progression from newly diagnosed to remission.

CONCLUSION

Our findings improve the understanding of the pathogenesis and progression of ITP, and may provide new directions for the development of treatment strategies.

Pharmacological inhibition of GSK3 promotes TNFα-induced GM-CSF via up-regulation of ERK signaling in nasopharyngeal carcinoma (NPC)

Granulocyte-macrophage colony stimulating factor (GM-CSF) functions to drive nasopharyngeal cancer (NPC) metastasis via recruitment and activation of macrophages. However, the source and the regulation of GM-CSF in tumor microenvironment of NPC are not fully understood. In this study, we found that TNFα induced GM-CSF production in NPC CNE1, CNE2, and 5-8F cells in time- and dose-dependent manners. GM-CSF production was tolerant, because the pre-treatment of NPC cells with TNFα down-regulated the GM-CSF production induced by TNFα re-treatment. TNFα activated glycogen synthase kinase-3 (GSK-3), which is an enzyme to regulate glycogen synthesis, and also is a critical downstream element of the PI3K/Akt to regulate cell survival. GSK3 inhibitors up-regulated TNFα-induced GM-CSF, and reversed GM-CSF tolerance induced by TNFα pre-treatment, suggesting that GSK3 activation down-regulated GM-CSF production. GM-CSF down-regulation was not related to ubiquitin-editing enzyme A20. The over-expression of A20 did not regulate GM-CSF production induced by TNFα. However, GSK3 inhibitors up-regulated ERK activation, which contributed to the production of GM-CSF induced by TNFα, suggesting that GSK3 negatively regulated TNFα-induced GM-CSF via down-regulation of ERK signaling. Taking together, these results suggested that GSK3 pathway may be a target for the regulation of TNFα-induced GM-CSF in the tumor microenvironment.

VE-822 mediated inhibition of ATR signaling sensitizes chondrosarcoma to cisplatin via reversion of the DNA damage response

Introduction

Cisplatin has been reported to elicit the DNA damage response (DDR) via activation of the ATR-Chk1 pathway, which in turn contributes to the induction of cisplatin resistance. Inhibition of ATR-Chk1 signaling reverses cisplatin resistance in some cancers. However, the influence of inhibiting ATR-Chk1 signaling on cisplatin resistance in chondrosarcoma cancer has not been reported.

Materials and methods

We compared the expression levels of ATR kinases in human nasopharyngeal carcinoma, choriocarcinoma and chondrosarcoma cell lines. We inhibited ATR kinase function with VE-822, a selective ATR inhibitor, and suppressed ATR kinase expression with shRNA. Western blotting, the CCK-8 assay, cell cycle distribution assay and apoptosis analysis were used to study the influence of inhibiting ATR-Chk1 signaling on reversing cisplatin resistance in chondrosarcoma cell lines.

Results

We found that chondrosarcoma cells expressed very low basal levels of phosphorylated ATR, but cisplatin treatment induced the activation of ATR-Chk1 signaling in a dose- and time-dependent manner, suggesting the induction of DDR. As expected, ATR inhibition with VE-822 reversed cisplatin-induced DDR and enhanced cisplatin-induced activation of H2AX, which is an important marker of DNA damage. Meanwhile, ATR inhibition by RNA interference also reversed DDR and promoted DNA damage. Furthermore, both pharmacological and molecular inhibition of ATR accelerated cisplatin-induced inhibition of cell proliferation and cell death.

Conclusion

Our results suggested that inhibiting ATR activation promoted cisplatin-induced cell death via reversion of DDR, and VE-822 may be a valuable strategy for the prevention of cisplatin resistance in chondrosarcoma.

Correlations of the expressions of c-Jun and Egr-1 proteins with clinicopathological features and prognosis of patients with nasopharyngeal carcinoma

This study intended to explore the correlation of the expressions of c-Jun and Egr-1 proteins with clinicopathological features and prognosis of patients with nasopharyngeal carcinoma (NPC). From January 2008 to January 2011, 123 NPC patients and 59 patients with chronic rhinitis were enrolled in this study. Fresh NPC and normal nasopharynx tissue specimens were obtained during surgery. Immunohistochemistry (IHC) was adopted to determine the positive expressions of the c-Jun and Egr-1 proteins. A 5-year clinical follow-up was conducted on all NPC patients. The Kaplan-Meier survival curve and Cox regression model were used for survival analysis. Compared with normal nasopharynx tissues, c-Jun expression was up-regulated but Egr-1 expression was down-regulated in NPC tissues. NPC patients with stage T3-T4 or stage III-IV had higher positive rates of c-Jun expression than those with stage T1-T2 or stage I-II. However, the positive rates of Egr-1 expression was higher in patients with stage T1-T2 or stage III-IV than those with stage T3-T4 or stage I-II. The survival rate of NPC patients with high c-Jun expression was lower than those with low/negative c-Jun expression, while the survival rate of NPC patients with high Egr-1 expression was higher than those with low/negative Egr-1 expression. The Cox regression analysis revealed that stage T3-T4, high c-Jun expression, and low Egr-1 expression were risk factors for poor prognosis of NPC patients. In conclusion, our study suggests that the c-Jun and Egr-1 proteins can serve as novel potential biomarkers for the early diagnosis and prognosis prediction of NPC.

Pre-treatment serum inflammatory cytokines as survival predictors of patients with nasopharyngeal carcinoma receiving chemoradiotherapy

The present study aimed to examine the predictability of pre-treatment serum levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α for determining the outcome of patients with nasopharyngeal carcinoma (NPC) assigned for chemoradiotherapy. A total of 35 patients with NPC were subjected to clinical examination and evaluation of performance status using Karnofsky scoring. Nasopharyngoscopy was performed for evaluation and to obtain a biopsy. Blood samples were obtained pre- and post-treatment for polymerase chain reaction quantitative estimation of Epstein-Barr virus (EBV) DNA plasma load and enzyme-linked immunosorbent assay for estimation of serum cytokines. All patients received chemoradiotherapy and were followed-up for 2 years. Cervical lymphadenopathy and recurrent attacks of epistaxis are the most common presenting symptoms. Treatment significantly decreased pre-treatment plasma EBV DNA load and serum levels of IL-6 and TNF-α, and increased serum IL-1β levels. Clinical staging and EBV DNA plasma load revealed positively significant correlation with pre-treatment serum levels of both IL-6 and TNF-α, while revealed negative significant correlation with serum IL-1β levels. The 2-year survival rate was negatively significantly correlated with pre-treatment levels of IL-6 and TNF-α, and EBV DNA viral load, while it was positively significantly correlated with pre-treatment performance scores and serum IL-1β levels. Statistical analyses defined high pre-treatment serum IL-6 levels as a significant specific predictor for high mortality rate. It was demonstrated that NPC was associated with high pre-treatment plasma EBV DNA load and serum cytokines, and chemoradiotherapy significantly reduced these high levels. High pre-treatment serum IL-6 level was a significant specific predictor for high mortality rate. Increased post-treatment serum levels of IL-1β indicated good therapeutic response and most probably a high survival rate.

Diet Quality Scores and Risk of Nasopharyngeal Carcinoma in Chinese Adults: A Case-Control Study

Many studies show that dietary factors may affect the risk of nasopharyngeal carcinoma (NPC). We examined the association between overall diet quality and NPC risk in a Chinese population. This case-control study included 600 NPC patients and 600 matched controls between 2009 and 2011 in Guangzhou, China. Habitual dietary intake and various covariates were assessed via face-to-face interviews. Diet quality scores were calculated according to the Healthy Eating Index-2005 (HEI-2005), the alternate Healthy Eating Index (aHEI), the Diet Quality Index-International (DQI-I), and the alternate Mediterranean Diet Score (aMed). After adjustment for various lifestyle and dietary factors, greater diet quality scores on the HEI-2005, aHEI, and DQI-I—but not on the aMed—showed a significant association with a lower risk of NPC (p-trends, <0.001–0.001). The odds ratios (95% confidence interval) comparing the extreme quartiles of the three significant scores were 0.47 (0.32–0.68) (HEI-2005), 0.48 (0.33–0.70) (aHEI), and 0.43 (0.30–0.62) (DQI-I). In gender-stratified analyses, the favorable association remained significant in men but not in women. We found that adherence to the predefined dietary patterns represented by the HEI-2005, aHEI, and DQI-I scales predicted a lower risk of NPC in adults from south China, especially in men.

Evaluation of Body Mass Index and Survival of Nasopharyngeal Carcinoma by Propensity-Matched Analysis: An Observational Case-Control Study

The effect of pretreatment body mass index on survival of nasopharyngeal carcinoma remains contradictory.All patients (N = 1778) underwent intensity-modulated radiotherapy with or without chemotherapy. Body mass index was categorized as underweight (<18.5 kg/m2), normal weight (18.5-22.9 kg/m2), overweight (22.9-27.5 kg/m2), and obesity (≥27.5 kg/m2). Propensity score matching method was used to identify patients with balanced characteristics and treatment regimen. Disease-specific survival (DSS), overall survival (OS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival were estimated by Kaplan-Meier method and Cox regression.Following propensity matching, 115 (underweight vs normal), 399 (overweight vs normal), and 93 (obese vs normal) pairs of patients were selected, respectively. In univariate analysis, underweight patients had inferior DSS/OS (P = 0.042) and DMFS (P = 0.025) while both overweight and obese patients showed similar survival across all the endpoints (P ≥ 0.098) to those with normal weight. In multivariate analysis, underweight remained predictive of poor DSS/OS (P = 0.044) and DMFS (P = 0.040), whereas overweight (P ≥ 0.124) or obesity (P ≥ 0.179) was not associated with any type of survival.Underweight increased the risk of death and distant metastasis, whereas overweight or obese did not affect the survival of nasopharyngeal carcinoma. This provides support for early nutritional intervention during the long waiting time before treatment.

Association of Upregulated HMGB1 and c-IAP2 Proteins With Hepatocellular Carcinoma Development and Progression

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most important health problems in China.

OBJECTIVES

This study analyzed expression of high-mobility group protein B1 (HMGB1) and inhibitor of apoptosis protein-2 (c-IAP2) proteins in HCC compared to paired para-tumor tissue samples to assess the association with HCC pathogenesis and progression.

MATERIALS AND METHODS

Sixty-eight HCC and para-tumor tissue samples were collected for Western blot, qRT-PCR and immunohistochemical analyses of HMGB1 and c-IAP2.

RESULTS

HMGB1 and c-IAP2 proteins were highly expressed in HCC tissue samples [85.3% (58/68) and 82.4% (56/68), respectively] compared to para-tumor tissue samples [32.3% and 27.9%, respectively]. Furthermore, expression of HMGB1 was significantly associated with enhanced c-IAP2 expression in HCC tissue samples (r = 0.878, P < 0.01). Expression of HMGB1 was associated with tumor multiplicity and size, alpha-fetoprotein (AFP) level and advanced TNM stage, while expression of c-IAP2 was associated with tumor size, AFP level and advanced TNM stage.

CONCLUSIONS

Expression of HMGB1 and c-IAP2 proteins was associated with HCC development and progression, and the expression of HMGB1 and c-IAP2 proteins in HCC were significantly associated with each other. Additionally, these proteins may show promise as biomarkers to predict HCC progression.

Nucleolin down-regulation is involved in ADP-induced cell cycle arrest in S phase and cell apoptosis in vascular endothelial cells

High concentration of extracellular ADP has been reported to induce cell apoptosis, but the molecular mechanisms remain not fully elucidated. In this study, we found by serendipity that ADP treatment of human umbilical vein endothelial cells (HUVEC) and human aortic endothelial cells (HAEC) down-regulated the protein level of nucleolin in a dose- and time-dependent manner. ADP treatment did not decrease the transcript level of nucloelin, suggesting that ADP might induce nucleolin protein degradation. HUVEC and HAEC expressed ADP receptor P2Y13 receptor, but did not express P2Y1 or P2Y12 receptors. However, P2Y1, 12, 13 receptor antagonists MRS2179, PSB0739, MRS2211 did not inhibit ADP-induced down-regulation of nucleolin. Moreover, MRS2211 itself down-regulated nucleolin protein level. In addition, 2-MeSADP, an agonist for P2Y1, 12 and 13 receptors, did not down-regulate nucleolin protein. These results suggested that ADP-induced nucleolin down-regulation was not due to the activation of P2Y1, 12, or 13 receptors. We also found that ADP treatment induced cell cycle arrest in S phase, cell apoptosis and cell proliferation inhibition via nucleolin down-regulation. The over-expression of nucleolin by gene transfer partly reversed ADP-induced cell cycle arrest, cell apoptosis and cell proliferation inhibition. Furthermore, ADP sensitized HUVEC to cisplatin-induced cell death by the down-regulation of Bcl-2 expression. Taken together, we found, for the first time to our knowledge, a novel mechanism by which ADP regulates cell proliferation by induction of cell cycle arrest and cell apoptosis via targeting nucelolin.