Dexamethasone Induces Apoptosis of Nasal Polyp-Derived Tissue Cultures Through JNK and p38 MAPK Activation

Imatinib prevents dexamethasone-induced pancreatic β-cell apoptosis via decreased TRAIL and DR5

Prolonged administration of dexamethasone, a potent anti-inflammatory drug, can lead to steroid-induced diabetes. Imatinib, a medication commonly prescribed for chronic myeloid leukemia (CML), has been shown to improve diabetes in CML patients. Our recent study demonstrated that dexamethasone induces pancreatic β-cell apoptosis by upregulating the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor, death receptor 5 (DR5). We hypothesized that imatinib may protect against dexamethasone-induced pancreatic β-cell apoptosis by reducing the expression of TRAIL and DR5, thereby favorably modulating downstream effectors in apoptotic pathways. We test this hypothesis by assessing the effects of imatinib on dexamethasone-induced apoptosis in rat insulinoma cell line cells. As anticipated, dexamethasone treatment led to increased TRAIL and DR5 expression, as well as an elevation in superoxide production. Conversely, expression of the TRAIL decoy receptor (DcR1) was decreased. Moreover, key effectors in the extrinsic and intrinsic apoptosis pathways, such as B-cell lymphoma 2 (BCL-2) associated X (BAX), nuclear factor kappa B (NF-κb), P73, caspase 8, and caspase 9, were upregulated, while the antiapoptotic protein BCL-2 was downregulated. Interestingly and importantly, imatinib at a concentration of 10 µM reversed the effect of dexamethasone on TRAIL, DR5, DcR1, superoxide production, BAX, BCL-2, NF-κB, P73, caspase 3, caspase 8, and caspase 9. Similar effects of imatinib on dexamethasone-induced TRAIL and DR5 expression were also observed in isolated mouse islets. Taken together, our findings suggest that imatinib protects against dexamethasone-induced pancreatic β-cell apoptosis by reducing TRAIL and DR5 expression and modulating downstream effectors in the extrinsic and intrinsic apoptosis pathways.

Partial Reversal of Anosmia Following Platinum-Based Chemotherapy in a Patient With Colorectal Adenocarcinoma

Platinum-based chemotherapy is known to cause taste and smell changes (TSCs) via a host of mechanisms, including altered receptor activity, saliva/mucus production, and induction of receptor destruction via mitotic inhibition. In the literature to date, these changes have primarily resulted in worsening of taste and smell. In this case report, we document the first instance of an individual regaining their sense of olfactory detection following treatment with oxaliplatin for colorectal adenocarcinoma. We theorize that the improvement in his sense of smell may have resulted from oxaliplatin-induced destruction of his nasal polyps through the caspase-9/procaspase-9 apoptotic pathway, a pathway shared with other mechanisms of nasal polyp destruction. These findings were supported by nasal endoscopy and sphenoid sinusoscopy, which demonstrated no clinical persistence of nasal polyps, in contrast to nasal endoscopy prior to chemotherapy which demonstrated persistent nasal polyposis. Objective smell testing post-treatment revealed a diminished ability to discriminate odors. Chemotherapy-induced TSCs play a key role in poor weight gain, food aversion, emotional distress, and an overall decrease in quality of life, and patients should be informed of these potential consequences prior to starting treatment. However, in patients with anosmia secondary to nasal polyposis, treatment with platinum-based chemotherapy may provide an additional therapeutic benefit. Further studies may help elucidate the potential therapeutic benefits of these agents in managing steroid-resistant polyposis for patients suffering from olfactory dysfunction.

Expression of Estrogen Receptor-alpha in Nasal Polyps and the Effects of Dexamethasone on Estrogen Receptor-alpha Expression in RPMI 2650 Cells

BACKGROUND

Studies have reported that epithelial cell proliferation may be involved in the pathogenesis of nasal polyps (NPs). Estrogen receptor (ER)-α, one type of ER, is related to anti-inflammatory action and cell survival in certain tissues. In this study, we examined the presence or absence of ER-α in NPs and healthy inferior turbinate mucosae. We also investigated the effect of dexamethasone on ER-α expression, cell viability, and apoptosis in RPMI 2650 cells.

METHODS

Immunohistochemical staining and Western blot analysis were conducted to determine the expression of ER-α in 15 NPs and 15 healthy inferior turbinate mucosae. After treating RPMI 2650 cells with dexamethasone, ER-α expression was analyzed using Western blot analysis and cell viability was determined using the MTT assay. Western blot analysis and annexin V-phycoerythrin (PE) staining were used to examine apoptotic cell death.

RESULTS

Western blot analysis showed that ER-α expression was upregulated in 13 of the 15 NP tissues. Immunohistochemical staining for ER-α confirmed the results of the Western blot analysis. When RPMI 2650 cells were treated with dexamethasone, both ER-α expression and cell viability were decreased. Furthermore, the treatment of RPMI 2650 cells with dexamethasone increased apoptotic cell death, as shown by increased levels of BAX and cleaved caspase-3, decreased levels of Bcl-2, and an increased percentage of positive annexin V-PE stained cells.

CONCLUSION

ER-α expression was higher in NPs than in healthy inferior turbinate mucosae. When RPMI 2650 cells were treated with dexamethasone, ER-α expression was downregulated, cell viability decreased, and apoptosis increased. The decreased cell viability may be related, at least in part, to the decreased ER-α protein levels, which likely contributed to the induction of apoptotic cell death in RPMI 2650 cells.

High PI3K/mTOR and low MAPK/JNK activity results in decreased apoptosis and autophagy in nasal polyposis

Introduction

Nasal polyposis is a progressive inflammatory disease that reduces the quality of life. The role of apoptotic and autophagic pathways in nasal polyposis pathogenesis is not yet clearly known.

Objective

In this study we aimed to investigate apoptotic (MAPK/JNK), anti-apoptotic (PI3K/mTOR) and autophagic (LC3) pathways which are related each other in the nasal polyposis tissues.

Methods

Twenty patients with nasal polyps and fifteen patients going through an inferior turbinate reduction were included in this study. Patients with asthma, Samter triad and allergic fungal sinusitis were excluded from the study. The apoptotic and autophagic pathways were investigated in paraffin-embedded nasal tissue sections of 20 NP and 15 samples from inferior turbinate reduction by H&E and immunohistochemistry with h-score. TUNEL method with apoptotic index was used to demonstrate apoptotic cells.

Results

Decreased immunoreactivity of P38 MAPK (p < 0.005) and JNK (p < 0.005) were observed in nasal polyposis compared to material from inferior turbinate reduction. This decrease may indicate a downregulation of apoptosis as demonstrated by decreased TUNEL staining in nasal polyposis (p < 0.005). The PI3K (p < 0.002) and mTOR (p < 0.005) immunoreactivities were increased in nasal polyposis. This increase indicates a downregulation of autophagy as demonstrated by decreased LC3 staining in nasal polyposis (p < 0.001).

Conclusion

Deficient apoptosis and autophagy through MAPK/JNK and PI3K/mTOR pathways may have a role in the pathogenesis of nasal polyposis.

Strength in diversity: Understanding the pathways to herpes simplex virus reactivation

Herpes simplex virus (HSV) establishes a latent infection in peripheral neurons and can periodically reactivate to cause disease. Reactivation can be triggered by a variety of stimuli that activate different cellular processes to result in increased HSV lytic gene expression and production of infectious virus. The use of model systems has contributed significantly to our understanding of how reactivation of the virus is triggered by different physiological stimuli that are correlated with recrudescence of human disease. Furthermore, these models have led to the identification of both common and distinct mechanisms of different HSV reactivation pathways. Here, we summarize how the use of these diverse model systems has led to a better understanding of the complexities of HSV reactivation, and we present potential models linking cellular signaling pathways to changes in viral gene expression.

Intralesional bleomycin A5 injection for the treatment of nasal polyps through inducing apoptosis

CONCLUSION

An intralesional bleomycin A5 (BLE) injection might be used as an alternative therapy for eosinophilic-type nasal polyps (NPs). BLE-induced apoptosis might play an important role in shrinkage of NPs.

OBJECTIVES

The aim of this study is to determine the effect and explore the possible role of apoptosis in shrinkage of NPs.

METHODS

Twenty-nine patients with eosinophilic-type NPs experienced repeated local injection of BLE. The recurrence rate of this group was obtained. The mechanism of BLE treatment was investigated through an in vitro experiment. Nasal polyp tissues were treated with BLE. The apoptotic activity was detected by the presence of DNA smear and test of terminal deoxynucleotidyl transferase dUTP nick end labeling. The caspase-8 and PARP were examined through immunohistochemistry and Western blotting.

RESULTS

After several local injections of BLE, the nasal polyp tissues decreased and then disappeared. During follow-up of 3 years the recurrence rate of this group was significantly lower than another one treated with operation plus medicine treatment. Apoptosis in BLE-treated tissue was prominently detected in the infiltrating inflammatory cells. The expression of PARP and casp-8 were increased in BLE-treated nasal polyp tissue compared with PBS-treated tissue.

A retrospective study of NENs and miR-224 promotes apoptosis of BON-1 cells by targeting PCSK9 inhibition

Neuroendocrine neoplasms (NENs) represent relatively rare tumors. The lack of diagnostic, therapeutic method and prognostic factors makes them a challenge to us. We retrospectively reviewed the data of 205 NENs patients among which 157 cases were followed-up. Proprotein convertase subtilisin/kexin 9 (PCSK9), a regulator of low density lipoprotein cholesterol (LDL-C), was confirmed as a target gene of microRNA-224. We found an increased incidence of NENs from 2012 to 2015. Women were usually diagnosed at earlier stages than men (P < 0.05). Tumor grading was associated with primary tumor site, especially esophagus and cardia NENs all at G3 (P <0.001). Age, tumor grading and LDL-C levels were independent risk factors of digestive NENs. Low LDL-C level was significantly correlated with survival rate and median overall survival (OS, P < 0.05). MicroRNA-224 agomir and PCSK9 siRNA could promote apoptosis and suppress proliferation, invasion of BON-1 cells (P < 0.05), but increase the level of glucocorticoid (GC, P < 0.05). Taken together, age, tumor grading and LDL-C level are independent risk factors of NENs. The miR-224/PCSK9/GC axis binds to tumorigenesis and prognosis of pancreatic NENs (p-NENs).

Induction of apoptosis by UV in the flat oyster, Ostrea edulis

Apoptosis is a fundamental feature in the development of many organisms and tissue systems. It is also a mechanism of host defense against environmental stress factors or pathogens by contributing to the elimination of infected cells. Hemocytes play a key role in defense mechanisms in invertebrates and previous studies have shown that physical or chemical stress can increase apoptosis in hemocytes in mollusks. However this phenomenon has rarely been investigated in bivalves especially in the flat oyster Ostrea edulis. The apoptotic response of hemocytes from flat oysters, O. edulis, was investigated after exposure to UV and dexamethasone, two agents known to induce apoptosis in vertebrates. Flow cytometry and microscopy were combined to demonstrate that apoptosis occurs in flat oyster hemocytes. Investigated parameters like intracytoplasmic calcium activity, mitochondrial membrane potential and phosphatidyl-serine externalization were significantly modulated in cells exposed to UV whereas dexamethasone only induced an increase of DNA fragmentation. Morphological changes were also observed on UV-treated cells using fluorescence microscopy and transmission electron microscopy. Our results confirm the apoptotic effect of UV on hemocytes of O. edulis and suggest that apoptosis is an important mechanism developed by the flat oyster against stress factors.

In Vitro Treatment with 2-APB Inhibits the Inflammation in Nasal Polyps

OBJECTIVE

Glucocorticoids are considered the main treatment option for chronic rhinosinusitis with nasal polyps (CRSwNP), but their effect rate ranges from 60.9% to 80%. Novel therapeutic means should be studied. The purpose of this study was to investigate the expression of Orai1 in nasal polyps (NPs) and the influence of intervention of Orai1 on NPs after in vitro treatment of 2-aminoethoxydiphenyl borate (2-APB).

STUDY DESIGN

Prospective cross-sectional study.

SETTING

University hospital.

SUBJECTS AND METHODS

Nasal biopsy samples were obtained from normal subjects or subjects with CRSwNP. We studied the localization of Orai1 protein in NPs by using immunohistochemistry. Then these tissues in cultures were maintained in the absence or presence of dexamethasone (DEX) or 2-APB. Orai1 was examined by Western blot, enzyme-linked immunosorbent assay (ELISA), and real-time reverse transcription-polymerase chain reaction (RT-PCR). Inflammatory mediators including interleukin (IL)-1β, IL-5, eosinophil cation protein (ECP), leukotriene (LT)C4, interferon (IFN)-γ, and dermatophagoides pteronyssinus (DP)-specific immunoglobulin E (sIgE) as well as mucins (MUCs) including MUC5B and MUC7 in cultures were analyzed with ELISA and real-time RT-PCR.

RESULTS

The expression of Orai1 was localized to cytoplasmic membrane of inflammatory cells and submucosal glandular cells and was upregulated in NPs compared with normal nasal mucosa. Orai1 was decreased in NPs after in vitro treatment of 2-APB but not after DEX intervention. The levels of inflammatory mediators and mucins were reduced more after 2-APB treatment when compared with those after DEX treatment.

CONCLUSION

Orai1 may play crucial roles in NP formation, and the intervention of Orai1 may inhibit NP development.

Dose- and time-dependent effects of triamcinolone acetonide on human rotator cuff-derived cells

Objectives

To investigate the appropriate dose and interval for the administration of triamcinolone acetonide (TA) in treating tendinopathy to avoid adverse effects such as tendon degeneration and rupture.

Methods

Human rotator cuff-derived cells were cultured using three media: regular medium (control), regular medium with 0.1 mg/mL of TA (low TA group), and with 1.0 mg/mL of TA (high TA group). The cell morphology, apoptosis, and viability were assessed at designated time points.

Results

In the low TA group, the cells became flattened and polygonal at seven days then returned to normal at 21 days. The cell apoptosis ratio and messenger ribonucleic acid expression of caspase-3, 7, 8, and 9 increased, and viability was reduced in the low and high groups at seven days. In the low TA group, apoptosis and viability returned to normal at 21 days, however, in the high TA group, the cell morphology, apoptosis ratio, caspase-3, 7, 8, and 9 and viability did not return by day 21. Re-administration was performed in the low TA group at 7-, 14-, and 21-day intervals, and cell viability did not return to the control level at the 7- and 14-day intervals.

Conclusion

A 0.1 mg/mL dose of TA temporarily decreased cell viability and increased cell apoptosis, which was recovered at 21 days, however, 1 mg/mL of TA caused irreversible damage to cell morphology and viability. An interval > three weeks was needed to safely re-administer TA. These findings may help determine the appropriate dose and interval for TA injection therapy.

Cite this article: Bone Joint Res 2014;3:328–34.