Plumbagin induces the apoptosis of drug-resistant oral cancer in vitro and in vivo through ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction.

BACKGROUND: Oral cancer is one of the leading causes of cancer-related deaths worldwide. Chemotherapy is widely used in the treatment of oral cancer, but its clinical efficacy is limited by drug resistance. Hence, novel compounds capable of overcoming drug-resistance are urgently needed. PURPOSE: Plumbagin (PG), a natural compound isolated from Plumbago zeylanica L, has been used to treat various cancers. In this study, we investigated the anticancer effects of PG on drug-resistant oral cancer (CR-SAS) cells, as well as the underlying mechanism. METHODS: MTT assays were used to evaluate the effect of PG on the viability of CR-SAS cells. Apoptosis and reactive oxygen species (ROS) production by the cells were determined using flow cytometry. Protein expression levels were detected by western blotting. RESULTS: The results show that PG reduces the viability and causes the apoptosis of CR-SAS cells. PG is able to induce intracellular and mitochondrial ROS generation that leads to mitochondrial dysfunction. Furthermore, endoplasmic reticulum (ER) stress was triggered in PG-treated CR-SAS cells. The inhibition of ROS using N-acetylcysteine (NAC) abrogated the PG-induced ER stress and apoptosis, as well as the reduction in cell viability. Meanwhile, similar results were observed both in zebrafish and in murine models of drug-resistant oral cancer. CONCLUSION: Our results indicate that PG induces the apoptosis of CR-SAS cells via the ROS-mediated ER stress pathway and mitochondrial dysfunction. It will be interesting to develop the natural compound PG for the treatment of drug-resistant oral cancer.

Chlorogenic Acid Inhibition of Esophageal Squamous Cell Carcinoma Metastasis via EGFR/p-Akt/Snail Signaling Pathways.

BACKGROUND/AIM: Chlorogenic acid (CGA) is a polyphenol compound found in a variety of foods, including coffee, tea, cherries, and apples. It has been found by a number of studies to affect the viability of human cancer cells. No study has investigated its effect on esophageal squamous cell carcinoma (ESCC) metastasis or the molecular mechanism underlying its effect on this disease. MATERIALS AND METHODS: We first used the Taiwanese ESCC cell line CE81T/VGH to create CE81T-M4 cells. Treatment of higher motility cells with chlorogenic acid for 24 h led to inhibition of cell migration and invasion as shown by scratch migration and transwell assays. RESULTS: Western blotting showed that chlorogenic acid halted the activation of EGFR/p-Akt/Snail pathway and suppressed the expression of MMP-2 and MMP-9. Knockdown of either EGFR or Akt inhibited Snail, MMP2, and MMP9 activity as well as cell migration and invasion. CONCLUSION: Chlorogenic acid inhibited cancer cell motility via the EGFR/p-Akt/Snail pathway and could potentially be used to develop an antimetastatic agent for ESCC in the future.

The Role of Nonapoptotic Programmed Cell Death - Ferroptosis, Necroptosis, and Pyroptosis - in Pancreatic Ductal Adenocarcinoma Treatment.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal cancer, with a dismal 5-year survival rate of less than 10%. It is estimated that approximately 80% of pancreatic ductal carcinoma (PDAC) patients are diagnosed at an advanced or metastatic stage. Hence, most patients are not appropriate candidates for surgical resection and therefore require systemic chemotherapy. However, it has been reported that most patients develop chemoresistance within several months, partly because of antiapoptotic mechanisms. Hence, inducing alternative programmed cell death (PCD), including ferroptosis, necroptosis or pyroptosis, seems to be a promising strategy to overcome antiapoptosis-mediated chemoresistance. In this review, we shed light on the molecular mechanisms of ferroptosis, necroptosis and pyroptosis and suggest several potential strategies (e.g., compounds and nanoparticles [NPs]) that are capable of triggering nonapoptotic PCD to suppress PDAC progression. In conclusion, these strategies might serve as adjuvants in combination with clinical first-line chemotherapies to improve patient survival rates.

diTFPP, a Phenoxyphenol, Sensitizes Hepatocellular Carcinoma Cells to C2-Ceramide-Induced Autophagic Stress by Increasing Oxidative Stress and ER Stress Accompanied by LAMP2 Hypoglycosylation.

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is the leading cause of cancer-related mortality worldwide. Chemotherapy is the major treatment modality for advanced or unresectable HCC; unfortunately, chemoresistance results in a poor prognosis for HCC patients. Exogenous ceramide, a sphingolipid, has been well documented to exert anticancer effects. However, recent reports suggest that sphingolipid metabolism in ceramide-resistant cancer cells favors the conversion of exogenous ceramides to prosurvival sphingolipids, conferring ceramide resistance to cancer cells. However, the mechanism underlying ceramide resistance remains unclear. We previously demonstrated that diTFPP, a novel phenoxyphenol compound, enhances the anti-HCC effect of C2-ceramide. Here, we further clarified that treatment with C2-ceramide alone increases the protein level of CERS2, which modulates sphingolipid metabolism to favor the conversion of C2-ceramide to prosurvival sphingolipids in HCC cells, thus activating the unfolded protein response (UPR), which further initiates autophagy and the reversible senescence-like phenotype (SLP), ultimately contributing to C2-ceramide resistance in these cells. However, cotreatment with diTFPP and ceramide downregulated the protein level of CERS2 and increased oxidative and endoplasmic reticulum (ER) stress. Furthermore, insufficient LAMP2 glycosylation induced by diTFPP/ceramide cotreatment may cause the failure of autophagosome-lysosome fusion, eventually lowering the threshold for triggering cell death in response to C2-ceramide. Our study may shed light on the mechanism of ceramide resistance and help in the development of adjuvants for ceramide-based cancer therapeutics.

Endoglin Modulates TGFßR2 Induced VEGF and Proinflammatory Cytokine Axis Mediated Angiogenesis in Prolonged DEHP-Exposed Breast Cancer Cells.

Angiogenesis is the process of vascular network development and plays a crucial role in cancer growth, progression, and metastasis. Phthalates are a class of environmental pollutants that have detrimental effects on human health and are reported to increase cancer risk. However, the interplay between phthalate exposure and angiogenesis has not been investigated thoroughly. In this study, we investigated the effect of prolonged di (2-ethylhexyl) phthalate (DEHP) treatment on the angiogenic potential of triple-negative breast cancer. MDA-MB-231 cells were exposed to physiological concentrations of DEHP for more than three months. Prolonged DEHP exposure induced angiogenesis in breast cancer cells. Endoglin (ENG)/CD105 is a membrane glycoprotein and an auxiliary receptor of the TGFß receptor complex. In endothelial cells, ENG is highly expressed and it is a prerequisite for developmental angiogenesis. A literature review highlights endoglin as a well-known mesenchymal stem cell marker responsible for vascular development and angiogenesis. NGS analysis showed that endoglin overexpression in DEHP-exposed MDA-MB-231 cells correlated with tumor development and growth. An in vivo zebrafish xenograft assay showed that VEGFA induced sprouting of the subintestinal vein (SIV) in embryos injected with DEHP-exposed cells. Endoglin knockdown reduced SIV sprouting and VEGFA expression in zebrafish embryos. An in vitro HUVEC tube formation assay showed that endoglin depletion reversed DEHP-induced VEGF-mediated HUVEC tube formation in coculture. DEHP-induced endoglin activated TGFß/SMAD3/VEGF and MAPK/p38 signaling in MDA-MB-231 cells. A cytokine angiogenesis antibody array showed induced expression of the inflammatory cytokines IL1α, IL1ß, IL6, and IL8, along with GMCSF and VEGF. Endoglin knockdown reversed DEHP-induced activation of the TGFß/SMAD3/VEGF signaling axis, MAPK/p38 signaling, and cytokine regulation, limiting angiogenesis potential both in vivo and in vitro. Targeting endoglin might serve as a potential alternative treatment to control angiogenesis, leading to metastasis and limiting cancer progression.

The Phenoxyphenol Compound diTFPP Mediates Exogenous C2-Ceramide Metabolism, Inducing Cell Apoptosis Accompanied by ROS Formation and Autophagy in Hepatocellular Carcinoma Cells.

Hepatocellular carcinoma (HCC) is a severe disease that accounts for 80% of liver cancers. Chemotherapy is the primary therapeutic strategy for patients who cannot be treated with surgery or who have late-stage HCC. C2-ceramide is an effective reagent that has been found to inhibit the growth of many cancer types. The metabolism of C2-ceramide plays a vital role in the regulation of cell death/cell survival. The phenoxyphenol compound 4-{2,3,5,6-tetrafluoro-4-[2,3,5,6-tetrafluoro-4-(4-hydroxyphenoxy)phenyl]phenoxy}phenol (diTFPP) was found to have a synergistic effect with C2-ceramide, resulting in considerable cell death in the HA22T HCC cell line. diTFPP/C2-ceramide cotreatment induced a two- to threefold increase in cell death compared to that with C2-ceramide alone and induced pyknosis. Annexin V/7-aminoactinomycin D (7AAD) double staining and Western blotting indicated that apoptosis was involved in diTFPP/C2-ceramide cotreatment-mediated cell death. We next analyzed transcriptome alterations in diTFPP/C2-ceramide-cotreated HA22T cells with next-generation sequencing (NGS). The data indicated that diTFPP treatment disrupted sphingolipid metabolism, inhibited cell cycle-associated gene expression, and induced autophagy and reactive oxygen species (ROS)-responsive changes in gene expression. Additionally, we assessed the activation of autophagy with acridine orange (AO) staining and observed alterations in the expression of the autophagic proteins LC3B-II and Beclin-1, which indicated autophagy activation after diTFPP/C2-ceramide cotreatment. Elevated levels of ROS were also reported in diTFPP/C2-ceramide-treated cells, and the expression of the ROS-associated proteins SOD1, SOD2, and catalase was upregulated after diTFPP/C2-ceramide treatment. This study revealed the potential regulatory mechanism of the novel compound diTFPP in sphingolipid metabolism by showing that it disrupts ceramide metabolism and apoptotic sphingolipid accumulation.

Curcumin Metabolite Tetrahydrocurcumin in the Treatment of Eye Diseases.

Curcumin is one of the most valuable natural products due to its pharmacological activities. However, the low bioavailability of curcumin has long been a problem for its medicinal use. Large studies have been conducted to improve the use of curcumin; among these studies, curcumin metabolites have become a relatively new research focus over the past few years. Additionally, accumulating evidence suggests that curcumin or curcuminoid metabolites have similar or better biological activity than the precursor of curcumin. Recent studies focus on the protective role of plasma tetrahydrocurcumin (THC), a main metabolite of curcumin, against tumors and chronic inflammatory diseases. Nevertheless, studies of THC in eye diseases have not yet been conducted. Since ophthalmic conditions play a crucial role in worldwide public health, the prevention and treatment of ophthalmic diseases are of great concern. Therefore, the present study investigated the antioxidative, anti-inflammatory, antiangiogenic, and neuroprotective effects of THC on four major ocular diseases: age-related cataracts, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR). While this study aimed to show curcumin as a promising potential solution for eye conditions and discusses the involved mechanistic pathways, further work is required for the clinical application of curcumin.

Direct Binding of Cisplatin to p22phox, an Endoplasmic Reticulum (ER) Membrane Protein, Contributes to Cisplatin Resistance in Oral Squamous Cell Carcinoma (OSCC) Cells.

Prolonged treatment with cisplatin (CDDP) frequently develops chemoresistance. We have previously shown that p22phox, an endoplasmic reticulum (ER) membrane protein, confers CDDP resistance by blocking CDDP nuclear entry in oral squamous cell carcinoma (OSCC) cells; however, the underlying mechanism remains unresolved. Using a fluorescent dye-labeled CDDP, here we show that CDDP can bind to p22phox in both cell-based and cell-free contexts. Subsequent detection of CDDP-peptide interaction by the Tris-Tricine-based electrophoresis revealed that GA-30, a synthetic peptide matching a region of the cytosolic domain of p22phox, could interact with CDDP. These results were further confirmed by liquid chromatography-mass spectrometry (LC-MS) analysis, from which MA-11, an 11-amino acid subdomain of the GA-30 domain, could largely account for the interaction. Amino acid substitutions at Cys50, Met65 and Met73, but not His72, significantly impaired the binding between CDDP and the GA-30 domain, thereby suggesting the potential CDDP-binding residues in p22phox protein. Consistently, the p22phox point mutations at Cys50, Met65 and Met73, but not His72, resensitized OSCC cells to CDDP-induced cytotoxicity and apoptosis. Finally, p22phox might have binding specificity for the platinum drugs, including CDDP, carboplatin and oxaliplatin. Together, we have not only identified p22phox as a novel CDDP-binding protein, but further highlighted the importance of such a drug-protein interaction in drug resistance.

Autophagy Is Deficient and May be Negatively Regulated by SERPINB3 in Middle Ear Cholesteatoma.

HYPOTHESIS: Whereas autophagy has been linked to various human diseases, whether it also plays a role in cholesteatoma is virtually unknown. This study aimed to investigate the activity and regulation of autophagy in cholesteatoma. BACKGROUND: The treatment of middle ear cholesteatoma has been challenging due to an insufficient understanding of the underlying disease mechanism. METHODS: Expression of microtubule-associated protein 1A/1B-light chain 3 (LC3), the autophagy protein marker, and phosphorylated Akt (p-Akt), and mammalian target of rapamycin (p-mTOR), the known autophagy regulators, in fresh retroauricular skin and cholesteatoma tissue samples was analyzed by immunoblotting. The results were further confirmed by immunohistochemistry and statistical analyses. Cell proliferation of primary retroauricular skin- and cholesteatoma-derived fibroblasts was evaluated by methyl thiazol tetrazolium (MTT) assay. Ectopic expression of serine proteinase inhibitor, clade B, member 3 (SERPINB3) in the fibroblasts was achieved by electroporation and the expression was detected by immunoblotting. RESULTS: LC3 expression was significantly decreased in cholesteatoma in most of the 15 paired retroauricular skin/cholesteatoma tissue samples. However, p-Akt and p-mTOR expression in the cholesteatoma samples was not significantly different from that in the control subjects. Immunohistochemical studies further demonstrated an inverse correlation between LC3 expression and cholesteatoma. The cholesteatoma fibroblasts proliferated faster than the retroauricular skin fibroblasts, and had higher SERPINB3 but lower LC3 expression. Furthermore, overexpression of SERPINB3 in the retroauricular skin fibroblasts enhanced cell proliferation and downregulated LC3 expression. CONCLUSION: Autophagy is significantly suppressed in cholesteatoma tissues, which may not involve the Akt/mTOR signaling pathway. More importantly, SERPINB3 may promote cell proliferation and negatively regulate autophagy in cholesteatoma fibroblasts. Together, these findings warrant further investigation into the pathogenic mechanism of cholesteatoma.

Human non­small cell lung cancer cells can be sensitized to camptothecin by modulating autophagy.

Lung cancer is a prevalent disease and is one of the leading causes of mortality worldwide. Despite the development of various anticancer drugs, the prognosis of lung cancer is relatively poor. Metastasis of lung cancer, as well as chemoresistance, is associated with a high mortality rate for patients with lung cancer. Camptothecin (CPT) is a well-known anticancer drug, which causes cancer cell apoptosis via the induction of DNA damage; however, the cytotoxicity of CPT easily reaches a plateau at a relatively high dose in lung cancer cells, thus limiting its efficacy. The present study demonstrated that CPT may induce autophagy in two human non­small cell lung cancer cell lines, H1299 and H460. In addition, the results of a viability assay and Annexin V staining revealed that CPT-induced autophagy could protect lung cancer cells from programmed cell death. Conversely, the cytotoxicity of CPT was increased when autophagy was blocked by 3-methyladenine treatment. Furthermore, inhibition of autophagy enhanced the levels of CPT-induced DNA damage in the lung cancer cell lines. Accordingly, these findings suggested that autophagy exerts a protective role in CPT-treated lung cancer cells, and the combination of CPT with a specific inhibitor of autophagy may be considered a promising strategy for the future treatment of lung cancer.

Differential resistance to platinum-based drugs and 5-fluorouracil in p22phox-overexpressing oral squamous cell carcinoma: Implications of alternative treatment strategies.

BACKGROUND: We have previously shown that p22phox confers resistance to cisplatin in oral squamous cell carcinoma (OSCC). Whether p22phox has clinical correlation with cisplatin resistance and affects the efficacy of other platinum or nonplatinum drugs is unknown. METHODS: The p22phox expression in tissues and apoptotic markers in cell lines was detected by immunoblotting. The cytotoxicity of chemotherapy drugs was determined by methylthiazol tetrazolium assay. In vivo chemoresistance of p22phox-overexpressing tumors was confirmed by the xenograft mouse model. RESULTS: The p22phox was upregulated in tumors of patients with OSCC refractory to cisplatin treatment. The p22phox overexpression markedly increased the resistance to cisplatin and carboplatin, but not oxaliplatin and 5-fluorouracil (5-FU), in OSCC cells by differentially inhibiting the drug-induced apoptosis. Furthermore, p22phox-dependent resistance to cisplatin, but not 5-FU, was demonstrated in mouse xenograft tumors. CONCLUSION: The p22phox expression may not only be a prognostic biomarker for prediction of chemotherapy outcomes, but the indication for alternative treatment strategies in oral cancer.

A Quinone-Containing Compound Enhances Camptothecin-Induced Apoptosis of Lung Cancer Through Modulating Endogenous ROS and ERK Signaling.

The natural compound camptothecin (CPT) derivatives have widely been used for anti-cancer treatments, including lung cancer. However, many chemoresistant cancer cells often develop a relatively higher threshold for inducing apoptosis, causing a limited efficacy of anti-cancer drugs. Likewise, lung cancer cells acquire chemoresistance against CPT analogs, such as irinotecan and topotecan, finally resulting in an unsatisfied outcome and poor prognosis of lung cancer patients. TFPP is a quinone-containing compound as a candidate for CPT-based combination chemotherapy. In this study, we examined the effect of TFPP and CPT cotreatment on non-small cell lung cancer (NSCLC) cells. Cell proliferation and flow cytometry-based Annexin-V/PI staining assays demonstrated the synergistic effect of TFPP on CPT-induced apoptosis in both NSCLC A549 and H1299 cells. The results of CPT and TFPP cotreatment cause the regulation of the ERK-Bim axis and the activation of mitochondrial-mediated caspase cascade, including caspase-9 and caspase-3. Besides, TFPP significantly enhanced CPT-induced endogenous reactive oxygen species (ROS) in the two NSCLC cells. In contrast, the treatment of N-acetyl-L-cysteine (NAC), an ROS scavenger, rescues the apoptosis of NSCLC cells induced by TFPP and CPT cotreatment, suggesting that the synergistic effect of TFPP on CPT-induced anti-NSCLC cells is through upregulating ROS production. Consequently, our results suggest that TFPP sensitizes NSCLC towards CPT-based chemotherapy may act through decreasing the apoptosis-initiating threshold. Therefore, TFPP may be a promising chemosensitizer for lung cancer treatment, and the underlying mechanism warrants further.

An Acetamide Derivative as a Camptothecin Sensitizer for Human Non-Small-Cell Lung Cancer Cells through Increased Oxidative Stress and JNK Activation.

In recent years, combination chemotherapy is a primary strategy for treating lung cancer; however, the issues of antagonism and side effects still limit its applications. The development of chemosensitizer aims to sensitize chemoresistant cancer cells to anticancer drugs and therefore improve the efficacy of chemotherapy. In this study, we examined whether N-[2-(morpholin-4-yl)phenyl]-2-{8-oxatricyclo[7.4.0.0,2,7]trideca-1(9),2(7),3,5,10,12-hexaen-4-yloxy}acetamide (NPOA), an acetamide derivative, sensitizes human non-small-cell lung cancer (NSCLC) H1299 cells towards camptothecin- (CPT-) induced apoptosis effects. Our results demonstrate that the combination of CPT and NPOA enhances anti-lung-cancer effect. The cytometer-based Annexin V/propidium iodide (PI) staining showed that CPT and NPOA cotreatment causes an increased population of apoptotic cells compared to CPT treatment alone. Moreover, Western blotting assay showed an enhancement of Bax expression and caspase cascade leading to cell death of H1299 cells. Besides, CPT and NPOA cotreatment-mediated disruption of mitochondrial membrane potential (MMP) in H1299 cells may function through increasing the activation of the stressed-associated c-Jun N-terminal kinase (JNK). These results showed that NPOA treatment sensitizes H1299 cells towards CPT-induced accumulation of cell cycle S phase and mitochondrial-mediated apoptosis through regulating endogenous ROS and JNK activation. Accordingly, NPOA could be a candidate chemosensitizer of CPT derivative agents such as irinotecan or topotecan in the future.

Autophagy is deficient and inversely correlated with COX-2 expression in nasal polyps: a novel insight into the inflammation mechanism.

BACKGROUND: Nasal polyposis is characterised by persistent inflammation of the upper airways. Autophagy has been implicated in many chronic inflammatory diseases. Whether autophagy plays a role in nasal polyp (NP) inflammation is completely unknown and deserves investigation. METHODS: LC3 and COX-2 expression, the common autophagy and inflammation indicators, respectively, was analysed by immunoblotting in fresh tissues of NP and control nasal mucosa (NM). Primary cultures of NP-derived fibroblasts (NPDFs) and NMDFs were established for in vitro studies. Autophagy was induced by amino acid starvation and LC3 ectopic overexpression or inhibited by 3-methyladenine in the fibroblasts. Inflammation was induced by IL1-ß and TNF-α. LC3 and COX-2 expression was confirmed in NP specimens by immunohistochemistry. RESULTS: LC3 expression was decreased while COX-2 expression was significantly increased in fresh NP tissues compared with the NM control. In NMDFs and NPDFs, autophagy induction by starvation and LC3 overexpression downregulated COX-2 expression. Conversely, autophagy inhibition by 3-methyladenine enhanced COX-2 expression. However, IL1-ß and TNF-α had no effect on autophagy. Immunohistochemical studies on the NP specimens showed that most displayed low LC3 expression, whereas COX-2 was highly expressed in >50% of the specimens. Examination of two consecutive NP sections from the same tissue blocks revealed a negative correlation between LC3 and COX-2 expression. CONCLUSION: Autophagy is deficient in NP tissues and COX-2 is negatively regulated by autophagy in NP-derived fibroblasts. Since COX-2 is essential for the production of pro-inflammatory mediators, this study might help interpret persistent mucosal inflammation in NP. Attenuation of inflammation by restoring autophagy might be a therapeutic strategy for treating NP.

BubR1 Acts as a Promoter in Cellular Motility of Human Oral Squamous Cancer Cells through Regulating MMP-2 and MMP-9.

BubR1 is a critical component of spindle assembly checkpoint, ensuring proper chromatin segregation during mitosis. Recent studies showed that BubR1 was overexpressed in many cancer cells, including oral squamous cell carcinomas (OSCC). However, the effect of BubR1 on metastasis of OSCC remains unclear. This study aimed to unravel the role of BubR1 in the progression of OSCC and confirm the expression of BubR1 in a panel of malignant OSCC cell lines with different invasive abilities. The results of quantitative real-time PCR showed that the mRNA level of BubR1 was markedly increased in four OSCC cell lines, Ca9-22, HSC3, SCC9 and Cal-27 cells, compared to two normal cells, normal human oral keratinocytes (HOK) and human gingival fibroblasts (HGF). Moreover, the expression of BubR1 in these four OSCC cell lines was positively correlated with their motility. Immunofluorescence revealed that BubR1 was mostly localized in the cytosol of human gingival carcinoma Ca9-22 cells. BubR1 knockdown significantly decreased cellular invasion but slightly affect cellular proliferation on both Ca9-22 and Cal-27 cells. Consistently, the activities of metastasis-associated metalloproteinases MMP-2 and MMP-9 were attenuated in BubR1 knockdown Ca9-22 cells, suggesting the role of BubR1 in promotion of OSCC migration. Our present study defines an alternative pathway in promoting metastasis of OSCC cells, and the expression of BubR1 could be a prognostic index in OSCC patients.

Vitamin D decreases the secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 in fibroblasts derived from Taiwanese patients with chronic rhinosinusitis with nasal polyposis.

Vitamin D and its derivatives have modulatory effects in immunological and inflammatory responses. Such properties suggest that they might have an impact on chronic inflammatory airway diseases, including nasal polyposis. The aim of this study was to understand the role of vitamin D in chronic rhinosinusitis with nasal polyps (CRSwNP) by investigating its effect on the secretion of matrix metalloproteinase-2 (MMP-2) and MMP-9 in nasal polyp-derived fibroblasts. Two primary fibroblast cultures were established from nasal polyp tissues obtained during surgery. The nasal polyp-derived fibroblasts were stimulated with tumor necrosis factor-α (TNF-α; 10 ng/mL) for 24 hours, followed by replacement with media alone or with vitamin D derivatives (calcitriol or tacalcitol; 10µM) and incubated for another 24 hours. After the treatments, the levels of MMP-2 and MMP-9 secreted were evaluated by both enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. ELISA results revealed that TNF-α could substantially stimulate the secretion of MMP-2 (p < 0.01) and MMP-9 (p < 0.001) in nasal polyp-derived fibroblasts. More importantly, such stimulatory effect was significantly suppressed by adding calcitriol (p ≤ 0.01 for MMP-2 and p < 0.001 for MMP-9) or tacalcitol (p < 0.005 for both MMP-2 and MMP-9). The ELISA results were also confirmed by Western blot analysis. The inhibitory effect of vitamin D derivatives on MMP-2 and MMP-9 secretion could potentiate their application in pharmacotherapy of Taiwanese CRSwNP patients.

Vitamin D decreases the secretion of eotaxin and RANTES in nasal polyp fibroblasts derived from Taiwanese patients with chronic rhinosinusitis with nasal polyps.

Eosinophils are important inflammatory cells involved in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). Vitamin D and its derivatives, in addition to their classic role as regulators of electrolytes homeostasis, have modulatory effects in immunological and inflammatory responses. Such properties suggest that vitamin D might also play a role in inflammatory airway diseases such as CRSwNP. In this study, we investigated the effect of vitamin D derivatives (calcitriol and tacalcitol) on the secretion of eotaxin and Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES), the two major eosinophil chemoattractants, in fibroblasts derived from the polyps of Taiwanese CRSwNP patients. Patients diagnosed with eosinophilic CRSwNP but without malignancies or asthma and undergoing elective endoscopic sinus surgery were recruited. Three primary fibroblast cultures were established using the polyp specimens obtained from these patients. The third to eighth passages of the fibroblasts were used for in vitro studies. Nasal polyp-derived fibroblasts were stimulated with IL-1ß (10 ng/mL) for 24 hours, followed by replacement with media alone or with calcitriol or tacalcitol (10 µM) and incubation for another 24 hours. After the treatments, the levels of secreted eotaxin and RANTES were evaluated by ELISA assays. The results showed that IL-1ß could substantially stimulate the secretion of eotaxin (p < 0.01) and RANTES (p < 0.01) in nasal polyp-derived fibroblasts. More importantly, this stimulatory effect was significantly suppressed by adding calcitriol (p ≤ 0.002 for eotaxin and p ≤ 0.008 for RANTES) or tacalcitol (p ≤ 0.009 for eotaxin and p ≤ 0.02 for RANTES). Therefore, the inhibitory effect of vitamin D derivatives on eotaxin and RANTES secretion might shed light not only on the disease mechanism, but also on the potential use of vitamin D in pharmacotherapy of Taiwanese patients with CRSwNP.

p22phox confers resistance to cisplatin, by blocking its entry into the nucleus.

Cisplatin (CDDP) is a potent chemotherapeutic agent but resistance to the drug remains a major challenge in cancer treatment. To evaluate the efficacy of CDDP in oral squamous cell carcinoma (OSCC), we found that p22phox was highly expressed in CDDP-resistant OSCC specimens. Knockdown of p22phox sensitized OSCC cell lines to CDDP (P < 0.05). Stable overexpression of p22phox augmented CDDP resistance, as evidenced by the significantly higher IC50 values. This cytoprotective effect was attributed to the abrogation of CDDP-induced apoptosis. Akt phosphorylation was increased in p22phox stable lines. However, blocking PI3K/Akt pathway only partially restored CDDP-induced apoptosis. In addition, the overexpressed p22phox in OSCC cells exhibited cytoplasmic localization with enhanced perinuclear expression, consistent with the localization pattern in OSCC specimens. Remarkably, CDDP entry into the nucleus was severely impaired in p22phox-overexpressing cells (P < 0.001), and cytoplasmically accumulated CDDP was co-localized with overexpressed p22phox. This was supported by decreased CDDP-DNA adduct formation and delayed chk1-p53 signaling activation. Together, overexpression of p22phox sequestered CDDP and caused defective CDDP entry into the nucleus, significantly attenuating CDDP-induced apoptosis. Such diminished apoptosis was further abolished by p22phox-activating PI3K/Akt pathway. Our work has suggested a novel biomarker and insight into the mechanism of CDDP resistance.

An iron-catalyzed cascade approach to benzo[b]carbazole synthesis followed by 1,4-sulfonyl migration.

A simple and straightforward approach was developed to construct 5H-benzo[b]carbazole derivatives by iron catalysis in a cascade sequence. The notable features of this work include an atom-economical cascade sequence, unprecedented 1,4-sulfonyl migration, tolerance of a variety of functional groups, good yields, and an economical catalytic system.

Autophagy is deficient in nasal polyps: implications for the pathogenesis of the disease.

BACKGROUND: Nasal polyposis is characterized by persistent inflammation but the pathogenesis is complex and still debatable. Autophagy has been associated with many human health problems including chronic inflammatory airway diseases. Whether autophagy plays a role in nasal polyps and could be a therapeutic target is completely unknown. METHODS: We studied light chain 3 (LC3) protein expression, a common indication of autophagy, in fresh tissue specimens of 5 nasal polyps and 6 normal nasal mucosa by Western blot analysis. The results were also confirmed by immunohistochemistry (IHC) using additional 25 paraffin-embedded nasal tissue sections. Finally the autophagic activity was validated in nasal polyp-derived fibroblasts by evaluating the number of green fluorescent protein (GFP)-labeled LC3 puncta. RESULTS: The expression of LC3 was dramatically decreased in all 5 nasal polyp tissues. In contrast, protein kinase B-mechanistic target of rapamycin (Akt-mTOR) signaling, an established negative regulator of autophagy, was significantly activated in these tissues. Immunohistochemical results further demonstrated a negative correlation between autophagy and nasal polyps (p < 0.05). GFP-LC3 puncta formation, an alternative indicator of autophagy, was also diminished in nasal polyp-derived fibroblasts (p < 0.01). CONCLUSION: Autophagy is deficient presumably due to suppression by high Akt-mTOR activity in nasal polyps, which may provide a molecular basis for future mechanistic study of the disease.