BMP-2 Induced Signaling Pathways and Phenotypes: Comparisons Between Senescent and Non-senescent Bone Marrow Mesenchymal Stem Cells.

The use of BMP-2 in orthopedic surgery is limited by uncertainty surrounding its effects on the differentiation of mesenchymal stem cells (MSCs) and how this is affected by cellular aging. This study compared the effects of recombinant human BMP-2 (rhBMP-2) on osteogenic and adipogenic differentiation between senescent and non-senescent MSCs. Senescent and non-senescent MSCs were cultured in osteogenic and adipogenic differentiation medium containing various concentrations of rhBMP-2. The phenotypes of these cells were compared by performing a calcium assay, adipogenesis assay, staining, real-time PCR, western blotting, and microarray analysis. rhBMP-2 induced osteogenic differentiation to a lesser extent (P < 0.001 and P = 0.005 for alkaline phosphatase activity and Ca2+ release) in senescent MSCs regardless of dose-dependent increase in both cells. However, the induction of adipogenic differentiation by rhBMP-2 was comparable between them. There was no difference between these two groups of cells in the adipogenesis assay (P = 0.279) and their expression levels of PPARγ were similar. Several genes such as CHRDL1, NOG, SMAD1, SMAD7, and FST encoding transcription factors were proposed to underlie the different responses of senescent and non-senescent MSCs to rhBMP-2 in microarray analyses. Furthermore, inflammatory, adipogenic, or cell death-related signaling pathways such as NF-kB or p38-MAPK pathways were upregulated by BMP-2 in senescent MSCs, whereas bone forming signaling pathways involving BMP, SMAD, and TGF- ß were upregulated in non-senescent MSCs as expected. This phenomenon explains bone forming dominance by non-senescent MSCs and possible frequent complications such as seroma, osteolysis, or neuritis in senescent MSCs during BMP-2 use in orthopedic surgery.

A Novel View of the Adult Stem Cell Compartment From the Perspective of a Quiescent Population of Very Small Embryonic-Like Stem Cells.

Evidence has accumulated that adult hematopoietic tissues and other organs contain a population of dormant stem cells (SCs) that are more primitive than other, already restricted, monopotent tissue-committed SCs (TCSCs). These observations raise several questions, such as the developmental origin of these cells, their true pluripotent or multipotent nature, which surface markers they express, how they can be efficiently isolated from adult tissues, and what role they play in the adult organism. The phenotype of these cells and expression of some genes characteristic of embryonic SCs, epiblast SCs, and primordial germ cells suggests their early-embryonic deposition in developing tissues as precursors of adult SCs. In this review, we will critically discuss all these questions and the concept that small dormant SCs related to migratory primordial germ cells, described as very small embryonic-like SCs, are deposited during embryogenesis in bone marrow and other organs as a backup population for adult tissue-committed SCs and are involved in several processes related to tissue or organ rejuvenation, aging, and cancerogenesis. The most recent results on successful ex vivo expansion of human very small embryonic-like SC in chemically defined media free from feeder-layer cells open up new and exciting possibilities for their application in regenerative medicine.

Longitudinal micro-endoscopic monitoring of high-success intramucosal xenografts for mouse models of colorectal cancer.

Colorectal cancer (CRC) is one of the most frequently lethal forms of cancer. Intramucosal injection allows development of better mouse models of CRC, as orthotopic xenografts allow development of adenocarcinoma in the submucosa of the mouse colon wall. In this paper, a method of orthotopic injection is monitored longitudinally using cellular-resolution real-time in vivo fluorescence microendoscopy, following the injection of three different cell lines: 3T3-GFP to confirm immunosuppression and HCT116-RFP cells to model CRC. Adenoma formation is first observable after 7 to 10 days, and by use of 33 G needles a tumor induction rate of greater than 85% is documented. An additional experiment on the injection of rapamycin reveals drug efficacy and localization between 24 and 48 hours, and suggests the promise of real-time cellular-resolution fluorescence micro-endoscopy for developing longitudinal therapy regimes in mural models of CRC.

Deep-Blue Thermally Activated Delayed Fluorescence Emitters Containing Diphenyl Sulfone Group for Organic Light Emitting Diodes.

Novel blue thermally activated delayed fluorescence (TADF) emitters, D1-DPS and D2-DPS, were designed and synthesized. Diphenyl sulfone (DPS) group functioned as a common acceptor, and it combined with each of two different spiro-acridine groups, D1 and D2. The calculated energy differences (ΔEST) of the singlet and triplet excited states of D1-DPS (0.062 eV) and D2-DPS (0.128 eV) had sufficiently small ΔEST values, which is favorable in the thermally activated reverse intersystem crossing (RISC) process from the T1 state to the S1 state. A device doped 10 wt% of D2-DPS with ADN host material, obtained 5.05% of external quantum efficiency with deep-blue emission having CIExy coordinates of (0.152, 0.065). The results showed that these molecules are promising host-free TADF deep-blue emitters by inhibiting concentration quenching.

Effects of the Trifluoromethyl Group on the Emission Efficiency of Red Phosphorescent Iridium(III) Complexes.

In this work, three novel phosphorescent iridium(III) complexes, namely (PT-TFP)2Ir(tmd), (PT-P)2Ir(tmd), and (MN-TFP)2Ir(tmd), were synthesized. All three complexes were phosphorescent red-emitting diode materials. The main ligands were synthesized by the Suzuki coupling reaction, and comprised an electron donor and an electron acceptor group. Subsequently, the iridium(III) complexes were synthesized by the Nonoyama reaction and their photochemical luminescence properties were investigated by ultraviolet-visible and photoluminescence spectroscopy. The manufactured devices were characterized by current density-voltage-luminance, power efficiency, external quantum efficiency, as well as their electroluminescence spectra. Finally, the effects of the trifluoromethyl group on the emission efficiency of the organic light-emitting diodes were investigated by comparing the energy levels and luminescence efficiency of the three iridium complexes.

Improvement of Liquid Crystal Alignment Using Novel Photo-Activators.

Photo-activator is a kind of additive that can improve the anchoring energy by attacking some of the bonds of polyimide (PI). Photo-activators were synthesized from the reaction of cyclohexanone oxime with three different anhydrides, respectively. Each activator generates different active radicals when irradiated. These fragmented and activated radicals are responsible for the liquid crystal (LC) alignment of PI film. The reactivity was confirmed through UV-Visible spectroscopy. All the three photo-activators had characteristic bimodal-shaped absorption peaks at 270∼280 nm. The photofragmentation reactions were completed within 1 min of UV irradiation, which implies that the activators are highly reactive to UV light. The short reaction time is very useful for liquid crystal display (LCD) factory applications. The photo-activator using crotonic anhydride (CAP) showed the highest surface anchoring energy, of 6.92 × 10-5 J/m2, compared to that of the other activators and that obtained by rubbing methods; (1.11 × 10-5 J/m2). This result was obtained due to resonance stabilization from the allyl radicals of CAP. The photo-activator using acetic anhydride (AAP) reached its maximum anchoring energy in less than 3 min of irradiation, which is the shortest optimum irradiation time. Considering the fact that this process does not require additional procedure and time, the photo-activators can be considered an innovate additive.

Effects of the Methyl Group on the Emission Efficiency of the Red Phosphorescent Iridium(III) Complexes for OLEDs.

Novel red phosphorescent iridium(III) complexes, namely (MN-Q)2Ir(tmd), (MN-MQ)2Ir(tmd), (PT-P)2Ir(tmd) and (PT-MP)2Ir(tmd) were synthesized for the red phosphorescent organic lightemitting diodes (phOLEDs). The ligands have sites of both the electron donor and acceptor in a molecule. The main ligands were synthesized by the Suzuki coupling reaction, and comprised an electron donor and an electron acceptor group. Subsequently, the iridium(III) complexes were synthesized by the Nonoyama reaction and their photochemical luminescence properties were investigated by ultraviolet-visible and photoluminescence spectroscopy. The manufactured devices were characterized by current density-voltage-luminance, power efficiency, external quantum efficiency, as well as their electroluminescence spectra. Finally, the effects of the trifluoromethyl group on the emission efficiency of the organic light-emitting diodes were investigated by comparing the energy levels and luminescence efficiency of the three iridium complexes.

Wip1 directly dephosphorylates NLK and increases Wnt activity during germ cell development.

Mice null for wild-type p53-induced phosphatase 1 (WIP1) display defects in testis development and spermatogenesis, resulting in reduced fertility. However, the molecular mechanism underlying these abnormalities in the testis remains uncharacterized. We report that the phosphatase activity of WIP1 increases Wnt activity through Nemo-like kinase (NLK). WIP1 directly interacted with NLK, which is highly homologous to p38 MAPK, a WIP1 substrate, and dephosphorylated its activation site. The WIP1-mediated inhibition of NLK activity markedly decreased the phosphorylation of lymphoid enhancer-binding factor 1 (LEF1), enhancing its interaction with ß-catenin. Additionally, WIP1 depletion impaired germ cell development, as evidenced by the expression of Oct4 and the germ cell-specific markers Ddx4, Nanos3 and Dnd1 during the development of germ cells from Oct4-GFP transgenic (OG2) mouse embryonic stem cells (mESCs). The expression of WIP1, whose level was significantly lower after the differentiation of germ cells from mESCs, occurred in parallel with the expression of germ cell development markers and SRY-box 17 (Sox17), a downstream target of Wnt. These results indicate that WIP1 is essential for germ cell development, which is known to require Wnt activity.

Histopathological characteristics of interstitial cystitis/bladder pain syndrome without Hunner lesion.

AIMS: To assess the distinct histopathological characteristics and their clinical significance between non-Hunner-type and Hunner-type interstitial cystitis (IC)/bladder pain syndrome (BPS). METHODS AND RESULTS: We prospectively enrolled and classified IC/BPS patients, on the basis of cystoscopic findings, as having non-Hunner-type IC and Hunner-type IC. Specimens obtained from the posterior wall in non-Hunner-type IC cases during hydrodistension or from Hunner/non-Hunner lesions in Hunner-type IC cases during transurethral resection were evaluated. Stress urinary incontinence patients with microscopic haematuria were selected as controls. Biopsy specimens were obtained from 15 non-Hunner-type IC, 15 Hunner-type IC and 5 non-IC patients. Severe and moderate fibrosis was more frequently observed in non-Hunner-type IC than in Hunner-type IC and non-IC cases. However, severe and moderate inflammation was more frequently observed in Hunner-type IC than in non-Hunner-type IC cases. The remnant urothelium was significantly decreased in Hunner-type IC cases as compared with non-Hunner-type IC and non-IC cases (P < 0.05), and non-Hunner-type IC cases showed a higher number of mast cells than Hunner-type IC and non-IC cases (P = 0.035). Accordingly, several fibrosis-promoting genes were highly expressed in bladder tissues of non-Hunner-type IC, as compared with Hunner-type IC. Patients with severe fibrosis showed significantly higher urinary frequency and smaller bladder capacity than those with moderate and mild fibrosis (all P < 0.05). CONCLUSIONS: Non-Hunner-type IC is characterized by severe fibrosis and increased mast cell infiltration, whereas Hunner-type IC is characterized by severe inflammation and urothelial denudation in the entire bladder. Fibrosis in the bladder of IC/BPS patients was correlated with increased urinary frequency and decreased bladder capacity.

Priming with ceramide-1 phosphate promotes the therapeutic effect of mesenchymal stem/stromal cells on pulmonary artery hypertension.

Some molecules enriched in damaged organs can contribute to tissue repair by stimulating the mobilization of stem cells. These so-called "priming" factors include bioactive lipids, complement components, and cationic peptides. However, their therapeutic significance remains to be determined. Here, we show that priming of mesenchymal stromal/stem cells (MSCs) with ceramide-1 phosphate (C1P), a bioactive lipid, enhances their therapeutic efficacy in pulmonary artery hypertension (PAH). Human bone marrow (BM)-derived MSCs treated with 100 or 200 µM C1P showed improved migration activity in Transwell assays compared with non-primed MSCs and concomitantly activated MAPK(p42/44) and AKT signaling cascades. Although C1P priming had little effect on cell surface marker phenotypes and the multipotency of MSCs, it potentiated their proliferative, colony-forming unit-fibroblast, and anti-inflammatory activities. In a monocrotaline-induced PAH animal model, a single administration of human MSCs primed with C1P significantly attenuated the PAH-related increase in right ventricular systolic pressure, right ventricular hypertrophy, and thickness of α-smooth muscle actin-positive cells around the vessel wall. Thus, this study shows that C1P priming increases the effects of MSC therapy by enhancing the migratory, self-renewal, and anti-inflammatory activity of MSCs and that MSC therapy optimized with priming protocols might be a promising option for the treatment of PAH patients.

Gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancers by accelerating EGFR turnover.

Gallic acid is a common botanic phenolic compound, which is present in plants and foods worldwide. Gallic acid is implicated in various biological processes such as cell growth and apoptosis. Indeed, gallic acid has been shown to induce apoptosis in many cancer types. However, the molecular mechanisms of gallic acid-induced apoptosis in cancer, particularly lung cancer, are still unclear. Here, we report that gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancer (NSCLC) cells, but not in EGFR-WT NSCLC cells. Treatment with gallic acid resulted in a significant reduction in proliferation and induction of apoptosis, only in EGFR-mutant NSCLC cells. Interestingly, treatment with gallic acid led to a robust decrease in EGFR levels, which is critical for NSCLC survival. Treatment with gallic acid had no significant effect on transcription, but induced EGFR turnover. Indeed, treatment with a proteasome inhibitor dramatically reversed gallic acid-induced EGFR downregulation. Moreover, treatment with gallic acid induced EGFR turnover leading to apoptosis in EGFR-TKI (tyrosine kinase inhibitor)-resistant cell lines, which are dependent on EGFR signaling for survival. Thus, these studies suggest that gallic acid can induce apoptosis in EGFR-dependent lung cancers that are dependent on EGFR for growth and survival via acceleration of EGFR turnover.

Stem Cell Therapy for Interstitial Cystitis/Bladder Pain Syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a disease characterized by pelvic pain, usually with urinary frequency. These symptoms make patients suffer from a poor quality of life. However, there is still a lack of consensus on the pathophysiology and curable treatment of IC/BPS. We have reviewed several candidates for the pathophysiology of this disease and also treatments that have been used. Although several oral medications, bladder instillation therapies, fulguration for Hunner's lesion, and hydrodistention have been tried as IC/BPS treatments, their outcomes have not been satisfactory. As the application of stem cell therapy is expanding into the urologic field, innovative strategies have been tested with animal models of IC/BPS and have shown promising therapeutic effects for reversing the symptoms of this disorder. Although several concerns about stem cell sources and their safety should be addressed before initiating human clinical trials, we introduce stem cell therapy as a valuable future treatment approach for IC/BPS.

The fibrosis of ketamine, a noncompetitive N-methyl-d-aspartic acid receptor antagonist dose-dependent change in a ketamine-induced cystitis rat model.

Ketamine abusers have greatly increased in number worldwide during recent years. The consumption of ketamine has increased, as have the number of published accounts of devastating urological sequelae. However, the mechanism of ketamine-associated urinary tract dysfunction remains unclear. This study was to evaluate the ketamine dose-dependency of ketamine-induced cystitis (KC) in a rat model. A total of 42 Sprague-Dawley rats (female, 10-week-old) were used. Each of the 7 KC rat models were induced by 1, 5, 10, 25 and 50 mg/kg ketamine intravenous injection for two weeks. For the sham group (n = 7), a phosphate-buffered saline (PBS) vehicle was used rather than ketamine hydrochloride. The cystometric parameters, histological examinations, staining for Masson's trichome, cytokeratin, toluidine blue and quantitative PCR were measured at two weeks following the intervention. The voiding interval gradually decreased depending upon the ketamine dose of 1, 5, 10, 25, or 50 mg/kg, respectively, and was decreased compared with Sham. Bladder capacity was decreased as ketamine dose increased. In particular, the increase of fibrosis and submucosal apoptosis were found according to the increase of the ketamine dose. The bladder apoptosis in the KC rat model makes the fibrotic bladder change, and led us to hypothesize that fibrosis could contribute to the lower urinary-tract symptoms. We suggest that according to the pathophysiology evidence, fibrosis induced by apoptosis plays a key role in KC.

Band gap control using electric field of photonic gel cells fabricated with block copolymer and hydrogel.

Optical and electrical characteristics of the devices using photonic gel film and hydrogel electrolyte were studied. Poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) lamellar film with alternating hydrophobic block and hydrophilic polyelectrolyte block polymers (52 kg/mol-b-57 kg/mol) were prepared for the photonic gel. Poly(isobutylene-co-maleic acid) sodium salts were prepared for the hydrogel. This hydrogel fiber is common water swelling material and it owned ions for a device has conductivity. Photonic gel and hydrogel was spin coating onto Indium-tin-oxide (ITO) glass for make electric fields. The reflectance maximum wavelength of photonic crystal device shifted from 538 nm and reached to 557 nm, 585 nm and 604 nm during 30 min voltage applying time. The bandwidth variation was very limited. Loss of electrolyte was much less with hydrogel compared to the pure water. We can control color of hydrogel used photonic device by electric field with reasonable time range under moderate electric field by applying 2 V between two facing electrodes.

Fabrication and electroluminescence properties of white organic light-emitting diode with a new yellow fluorescent dopant.

A new yellow fluorescent material, (2Z)-3-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2'-yl]-2-phenylacrylonitrile (BDAT-P), have been synthesized for use in organic light-emitting diodes. Opto-electronic properties of device with the structure of ITO (180 nm)/NPB (50 nm)/MADN:PFVtPh (SYB-41) 8% (17 nm)/CBP (5 nm)/CBP:Ir(pq)2acac 8% (3 nm)/CBP (5 nm)/MADN:BDAT-P 8% (3 nm)/CBP (5 nm)/MADN:SYB-41 8% (17 nm)/TPBi (40 nm)/Liq (2 nm)/Al (100 nm) was measured and revealed that BDAT-P was sufficiently applicable as a dopant of one of emitting layers in white light-emitting diodes. Maximum luminance of device was measured to be 26,950 cd/m2. Maximum luminous and quantum efficiency were observed to be 14.22 cd/A and 6.58%, respectively. The device emitted warm white light corresponding to Commission Internationale de l'Eclairage (CIExy) coordinates of (0.372, 0.424) at 11 V, (0.375,0.417) at 12 V, (0.372,0.409) at 13 V, (0.366, 0.401) at 14 V, and (0.360, 0.393) at 15 V, respectively.

Effects of co-doping on the red fluorescent OLEDS.

The device performance of red organic light-emitting diodes (OLEDs) was dramatically improved by co-doping of the red fluorescent material of (2Z,2'Z)-3,3'-[4,4"-bis(dimethylamino)-1,1':4',1"-terphenyl-2',5'-diyl]-bis(2-phenylacrylonitrile) (ABCV-P) with the hole transport material of N'-bis-(1-naphyl)-N,N'-diphenyl-1,1 '-biphenyl-4,4'-diamine (NPB) and the electron transport material of bis(2-methyl-8-quninolinato)-4-phenylphenolate aluminum (BAlq). The device structures were ITO/NPB/emitting layers/BAlq/Liq/Al in which the emitting layers were MADN:ABCV-P (40%) (device A), MADN:ABCV-P (40%):NPB (10%) (device B), MADN:ABCV-P (40%):BAlq (10%) (device C) and MADN:ABCV-P (40%):NPB (10%):BAlq (10%) (device D), respectively. The device D co-doped with NPB and BAlq exhibited maximum luminance of 9784 cd/m2, maximum luminous efficiency of 2.82 cd/A and maximum quantum efficiency of 3.19%, respectively, whereas those of the device A doped with only ABCV-P were 7563 cd/m2, 1.98 cd/A and 1.99%.

Stem cell therapy for interstitial cystitis/bladder pain syndrome.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic disease with limited treatment options. Current multidisciplinary approach targeting bladder inflammation and urothelial dysfunction has limited durable effect that major surgery is ultimately required for both Hunner and non-Hunner type IC. Various investigational attempts are underway to avoid such operations and preserve the urinary bladder. Stem cell therapy is a fascinating option for treating chronic illnesses. Stem cells can self-renew, restore damaged tissue, and have paracrine effects. The therapeutic efficacy and safety of stem cell therapy have been demonstrated in numerous preclinical models, primarily chemically induced cystitis rat models. Only one clinical trial (phase 1 study) has investigated the safety of human embryonic stem cell-derived mesenchymal stem cells in three Hunner-type IC patients. Under general anesthesia, participants underwent cystoscopic submucosal stem cell injection (2.0 × 107 stem cells/5 mL). No safety issues were reported up to 12 months of follow-up and long-term follow-up (up to 3 years). Although there were variations in therapeutic response, all patients reported significant improvement in pain at 1 month postoperatively. One patient underwent fulguration of the Hunner lesion after the trial, but others reported an overall improvement in pain. The analysis on phase 1/2a trial which had several modifications in protocol is currently ongoing. Despite several limitations that need to be overcome, stem cell therapy could be a potential therapeutic option for treating IC/BPS. Clinical outcome on phase 1/2a trial is important and might provide more insight into the clinical application of stem cell therapy for IC/BPS.

Assessment of the Therapeutic Effectiveness of Glutathione-Enhanced Mesenchymal Stem Cells in Rat Models of Chronic Bladder Ischemia-Induced Overactive Bladder and Detrusor Underactivity.

Overactive bladder (OAB) and detrusor underactivity (DUA) are representative voiding dysfunctions with a chronic nature and limited treatment modalities, and are ideal targets for stem cell therapy. In the present study, we investigated the therapeutic efficacy of human mesenchymal stem cells (MSCs) with a high antioxidant capacity generated by the Primed Fresh OCT4 (PFO) procedure in chronic bladder ischemia (CBI)-induced OAB and DUA rat models. Sixteen-week-old male Sprague-Dawley rats were divided into three groups (sham, OAB or DUA, and stem cell groups; n=10, respectively). CBI was induced by bilateral iliac arterial injury (OAB, 10 times; DUA, 30 times) followed by a 1.25% cholesterol diet for 8 weeks. Seven weeks after injury, rats in the stem cell and other groups were injected with 1×106 PFO-MSCs and phosphate buffer, respectively. One week later, bladder function was analyzed by awake cystometry and bladders were harvested for histological analysis. CBI with a high-fat diet resulted in atrophy of smooth muscle and increased collagen deposits correlating with reduced detrusor contractility in both rat models. Arterial injury 10 and 30 times induced OAB (increased number of non-voiding contractions and shortened micturition interval) and DUA (prolonged micturition interval and increased residual volume), respectively. Injection of PFO-MSCs with the enhanced glutathione dynamics reversed both functional and histological changes; it restored the contractility, micturition interval, residual volume, and muscle layer, with reduced fibrosis. CBI followed by a high-fat diet with varying degrees of arterial injury induced OAB and DUA in rats. In addition, PFO-MSCs alleviated functional and histological changes in both rat models.

Glutamine-mediated epigenetic regulation of cFLIP underlies resistance to TRAIL in pancreatic cancer.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent because it kills cancer cells while sparing normal cells. However, many cancers, including pancreatic ductal adenocarcinoma (PDAC), exhibit intrinsic or acquired resistance to TRAIL, and the molecular mechanisms underlying TRAIL resistance in cancers, particularly in PDAC, remain unclear. In this study, we demonstrated that glutamine (Gln) endows PDAC cells with resistance to TRAIL through KDM4C-mediated epigenetic regulation of cFLIP. Inhibition of glutaminolysis significantly reduced the cFLIP level, leading to TRAIL-mediated formation of death-inducing signaling complexes. Overexpression of cFLIP dramatically rescued PDAC cells from TRAIL/Gln deprivation-induced apoptosis. Alpha-Ketoglutarate (aKG) supplementation significantly reversed the decrease in the cFLIP level induced by glutaminolysis inhibition and rescued PDAC cells from TRAIL/Gln deprivation-induced apoptosis. Knockdown of glutamic-oxaloacetic transaminase 2, which facilitates the conversion of oxaloacetate and glutamate into aspartate and aKG, decreased aKG production and the cFLIP level and activated TRAIL-induced apoptosis. AKG-mediated epigenetic regulation was necessary for maintaining a high level of cFLIP. Glutaminolysis inhibition increased the abundance of H3K9me3 in the cFLIP promoter, indicating that Gln-derived aKG production is important for Jumonji-domain histone demethylase (JHDM)-mediated cFLIP regulation. The JHDM KDM4C regulated cFLIP expression by binding to its promoter, and KDM4C knockdown sensitized PDAC cells to TRAIL-induced apoptosis. The present findings suggest that Gln-derived aKG production is required for KDM4C-mediated epigenetic regulation of cFLIP, which leads to resistance to TRAIL.

IFITM3-mediated activation of TRAF6/MAPK/AP-1 pathways induces acquired TKI resistance in clear cell renal cell carcinoma.

PURPOSE: Vascular endothelial growth factor tyrosine kinase inhibitors (TKIs) have been the standard of care for advanced and metastatic clear cell renal cell carcinoma (ccRCC). However, the therapeutic effect of TKI monotherapy remains unsatisfactory given the high rates of acquired resistance to TKI therapy despite favorable initial tumor response. MATERIALS AND METHODS: To define the TKI-resistance mechanism and identify new therapeutic target for TKI-resistant ccRCC, an integrative differential gene expression analysis was performed using acquired resistant cohort and a public dataset. Sunitinib-resistant RCC cell lines were established and used to test their malignant behaviors of TKI resistance through in vitro and in vivo studies. Immunohistochemistry was conducted to compare expression between the tumor and normal kidney and verify expression of pathway-related proteins. RESULTS: Integrated differential gene expression analysis revealed increased interferon-induced transmembrane protein 3 (IFITM3) expression in post-TKI samples. IFITM3 expression was increased in ccRCC compared with the normal kidney. TKI-resistant RCC cells showed high expression of IFITM3 compared with TKI-sensitive cells and displayed aggressive biologic features such as higher proliferative ability, clonogenic survival, migration, and invasion while being treated with sunitinib. These aggressive features were suppressed by the inhibition of IFITM3 expression and promoted by IFITM3 overexpression, and these findings were confirmed in a xenograft model. IFITM3-mediated TKI resistance was associated with the activation of TRAF6 and MAPK/AP-1 pathways. CONCLUSIONS: These results demonstrate IFITM3-mediated activation of the TRAF6/MAPK/AP-1 pathways as a mechanism of acquired TKI resistance, and suggest IFITM3 as a new target for TKI-resistant ccRCC.