Does Gadolinium Deposition Lead to Metabolite Alteration in the Dentate Nucleus? An MRS Study in Patients with MS

BACKGROUND AND PURPOSE

Repeat contrast-enhanced MR imaging exposes patients with relapsing-remitting MS to frequent administration of gadolinium-based contrast agents. We aimed to investigate the potential metabolite and neurochemical alterations of visible gadolinium deposition on unenhanced T1WI in the dentate nucleus using MRS.

MATERIALS AND METHODS

This prospective study was conducted in a referral university hospital from January 2020 to July 2021. The inclusion criteria for case and control groups were as follows: 1) case: patients with relapsing-remitting MS, visible gadolinium deposition in the dentate nucleus (ribbon sign), >5 contrast-enhanced MR images obtained; 2) control 1: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, >5 contrast-enhanced MR images obtained; 3) control 2: patients with relapsing-remitting MS without visible gadolinium deposition in the dentate nucleus, <5 contrast-enhanced-MR images obtained; and 4) control 3: adult healthy individuals, with no contrast-enhanced MR imaging. Dentate nucleus and pontine single-voxel 12 × 12 × 12 MRS were analyzed using short TEs.

RESULTS

Forty participants (10 per group; 27 [67.5%] female; mean age, 35.6 [SD, 9.6] years) were enrolled. We did not detect any significant alteration in the levels of NAA and choline between the studied groups. The mean concentrations of mIns were 2.7 (SD, 0.73) (case), 1.5 (SD, 0.8) (control 1), 2.4 (SD, 1.2) (control 2), and 1.7 (SD, 1.2) (control 3) (P = .04). The mean concentration of Cr and mIns (P = .04) and the relative metabolic concentration (dentate nucleus/pons) of lipid 1.3/Cr (P = .04) were significantly higher in the case-group than in healthy individuals (controls 1-3). Further analyses compared the case group with cumulative control 1 and 2 groups and showed a significant increase in lactate (P = .02), lactate/Cr (P = .04), and Cr (dentate nucleus/pons) (P = .03) in the case group.

CONCLUSIONS

Although elevated concentrations of Cr, lactate, mIns, and lipid in the dentate nucleus of the case group indicate a metabolic disturbance, NAA and choline levels were normal, implying no definite neuronal damage.

Late-onset neuromyelitis optica spectrum disorder: A case series from Iran

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is a disabling autoimmune disease of the central nervous system that can start at ages of 50 or more, when it is called late-onset NMOSD (LO-NMOSD). Data on this disorder are sparse. In this cross-sectional study, patient characteristics of the disease were studied. LO-NMOSD patients of a tertiary center in Tehran were studied from 2016 to 2020.

CASE REPORTS

Eight patients were identified, half of whom were men. The diagnostic delay was from no time-lapse to three years (mean: 0.62, SD: 1.06), which was significantly shorter than in early-onset patients. Seven patients (87.5%) tested positive for AQP4-IgG which was significantly higher compared to early-onset patients (p-value=0.01). Four patients (50%) had both transverse myelitis and optic neuritis as presenting symptoms, while three (38%) had just myelitis and only one (12%) had optic neuritis.

CONCLUSION

There is discrepancy regarding different aspects of LO-NMOSD. Further studies are needed to clarify the subject in order to enhance diagnosis and treatment.

Thermal proteome profiling identifies PIP4K2A and ZADH2 as off-targets of Polo-like kinase 1 inhibitor volasertib

Polo-like kinase 1 (PLK1) is an important cell cycle kinase and an attractive target for anticancer treatments. An ATP-competitive small molecular PLK1 inhibitor, volasertib, has reached phase III in clinical trials in patients with refractory acute myeloid leukemia as a combination treatment with cytarabine. However, severe side effects limited its use. The origin of the side effects is unclear and might be due to insufficient specificity of the drug. Thus, identifying potential off-targets to volasertib is important for future clinical trials and for the development of more specific drugs. In this study, we used thermal proteome profiling (TPP) to identify proteome-wide targets of volasertib. Apart from PLK1 and proteins regulated by PLK1, we identified about 200 potential volasertib off-targets. Comparison of this result with the mass-spectrometry analysis of volasertib-treated cells showed that phosphatidylinositol phosphate and prostaglandin metabolism pathways are affected by volasertib. We confirmed that PIP4K2A and ZADH2-marker proteins for these pathways-are, indeed, stabilized by volasertib. PIP4K2A, however, was not affected by another PLK1 inhibitor onvansertib, suggesting that PIP4K2A is a true off-target of volasertib. Inhibition of these proteins is known to impact both the immune response and fatty acid metabolism and could explain some of the side effects seen in volasertib-treated patients.

PTENP1-AS contributes to BRAF inhibitor resistance and is associated with adverse clinical outcome in stage III melanoma

BRAF inhibitors (BRAFi) selectively target oncogenic BRAFV600E/K and are effective in 80% of advanced cutaneous malignant melanoma cases carrying the V600 mutation. However, the development of drug resistance limits their clinical efficacy. Better characterization of the underlying molecular processes is needed to further improve treatments. We previously demonstrated that transcription of PTEN is negatively regulated by the PTEN pseudogene antisense RNA, PTENP1-AS, and here we investigated the impact of this transcript on clinical outcome and BRAFi resistance in melanoma. We observed that increased expression levels of PTENP1-AS in BRAFi resistant cells associated with enrichment of EZH2 and H3K27me3 at the PTEN promoter, consequently reducing the expression levels of PTEN. Further, we showed that targeting of the PTENP1-AS transcript sensitized resistant cells to BRAFi treatment and that high expression of PTENP1-AS in stage III melanoma correlated with poor survival. Collectively, the data presented here show that PTENP1-AS is a promising target for re-sensitizing cells to BRAFi and also a possible prognostic marker for clinical outcome in stage III melanoma.

Intra-hospital dissemination of clinical and environmental isolates of Stenotrophomonas maltophilia from Tehran

Stenotrophomonas maltophilia isolates are responsible for various hospital-acquired infections and are particularly increasing in the immunocompromised patients. The aim of this study was to determine the clonal relatedness between S. maltophilia isolates originating from the clinic and environment. A total of 150 S. maltophilia isolates from patients and 1108 environmental samples obtained in three hospitals from Tehran. Following molecular identification targeting 23S rRNA gene, the clonal relatedness of the environmental and clinical isolates was determined using pulsed field gel electrophoresis (PFGE). Of the 150 clinical and 18 environmental isolates identified using phenotypic tests, the speciation of 120 and 15 was confirmed by targeting the 23S rRNA gene. The 24 common pulsotypes (PTs) and 32 single PTs were identified by PFGE. Only a small cluster was shared among the clinic and environment within a hospital; therefore, the intra-hospital dissemination of certain isolates of S. maltophilia among the clinic and environment was demonstrated.

Human proteins incorporated into tick-borne encephalitis virus revealed by in situ proximity ligation

Host proteins incorporated into virus particles have been reported to contribute to infectivity and tissue-tropism. This incorporation of host proteins is expected to be variable among viral particles, however, protein analysis at single-virus levels has been challenging. We have developed a method to detect host proteins incorporated on the surface of virions using the in situ proximity ligation assay (isPLA) with rolling circle amplification (RCA), employing oligonucleotide-conjugated antibody pairs. The technique allows highly selective and sensitive antibody-based detection of viral and host proteins on the surface of individual virions. We detected recombinant noninfectious sub-viral particles (SVPs) of tick-borne encephalitis virus (TBEV) immobilized in microtiter wells as fluorescent particles detected by regular fluorescence microscopy. Counting the particles in the images enabled us to estimate individual TBEV-SVP counts in different samples. Using isPLA we detected individual calnexin-, CD9-, CD81-, CD29- and CD59-positive SVPs among the viral particles. Our data suggests that a diversity of host proteins may be incorporated into TEBV, illustrating that isPLA with digital counting enables single-virus analysis of host protein incorporation.

A case study on aneurysmal bone cyst of T2 vertebral body in a 7-year-old girl: Anterior and posterior surgical approach for tumor resection and spinal reconstruction

Aneurysmal bone cyst (ABC) is defined as a benign lesion of bone containing blood-filled channels divided by soft-tissue septa and mostly diagnosed in children and adolescents. In the present study, the case of a 7-year-old girl with spastic paraparesia and left foot drop was investigated. Spinal imaging revealed a large lytic mass in the posterior elements of the T2 vertebral body, which resulted in the partial collapse of the T2 vertebral body, a T1 to T3 dislocation, and a spinal sagittal imbalance. The patient underwent a two-stage surgical procedure including an anterior T2 corpectomy, T1/T2 and T2/T3 discectomy, anterior instrumentation, posterior total tumor resection, and posterior fixation with laminar hooks. Postoperative imaging demonstrated cord decompression and good spinal alignment. Although a spinal ABC is a rare entity, it can occur in any segment of the spinal column and cause cord compression and spinal instability. Thus, proper treatment planning is crucial for total tumor resection to avoid tumor recurrence and correct spinal imbalance.

Exhaustion of CD4+ T-cells mediated by the Kynurenine Pathway in Melanoma

Kynurenine pathway (KP) activation by the enzymatic activity of indoleamine 2,3-dioxygenase1 (IDO1) and kynurenine (KYN) production represents an attractive target for reducing tumour progression and improving anti-tumour immunity in multiple cancers. However, immunomodulatory properties of other KP metabolites such as 3-hydroxy kynurenine (3-HK) and kynurenic acid (KYNA) are poorly understood. The association of the kynurenine metabolic pathway with T-cell status in the tumour microenvironment were characterized, using gene expression data of 368 cutaneous skin melanoma (SKCM) patients from the TCGA cohort. Based on the identified correlations, we characterized the production of KYN, 3-HK, and KYNA in vitro using melanoma-derived cell lines and primary CD4+ CD25- T-cells. Activation of the CD4+ T-cells produced IFNγ, which yielded increased levels of KYN and KYNA. Concurrently, kynurenine 3-monooxygenase (KMO) expression and proliferation of CD4+ T-cells were reduced, whereas exhaustion markers such as PD-L1, AHR, FOXP3, and CTLA4 were increased. Additionally, an analysis of the correlation network reconstructed using TCGA-SKCM emphasized KMO and KYNU with high variability among BRAF wild-type compared with V600E, which underscored their role in distinct CD4+ T-cell behavior in tumour immunity. Our results suggest that, in addition to IDO1, there is an alternative immune regulatory mechanism associated with the lower KMO expression and the higher KYNA production, which contributes to dysfunctional effector CD4+ T-cell response.

Polo-like kinases and acute leukemia

Acute leukemia is a common malignancy among children and adults worldwide and many patients suffer from chronic health issues using current therapeutic approaches. Therefore, there is a great need for the development of novel and more specific therapies with fewer side effects. The family of Polo-like kinases (Plks) is a group of five serine/threonine kinases that play an important role in cell cycle regulation and are critical targets for therapeutic invention. Plk1 and Plk4 are novel targets for cancer therapy as leukemic cells often express higher levels than normal cells. In contrast, Plk2 and Plk3 are considered to be tumor suppressors. Several small molecule inhibitors have been developed for targeting Plk1 inhibition. Despite reaching phase III clinical trials, one of the ATP-competitive Plk1 inhibitor, volasertib, did not induce an objective clinical response and even caused lethal side effects in some patients. In order to improve the specificity of the Plk1 inhibitors and reduce off-target side effects, novel RNA interference (RNAi)-based therapies have been developed. In this review, we summarize the mechanisms of action of the Plk family members in acute leukemia, describe preclinical studies and clinical trials involving Plk-targeting drugs and discuss novel approaches in Plk targeting.

Anteromedial GPi deep brain stimulation in Tourette syndrome: The first case series from Iran

OBJECTIVES

Tourette syndrome (TS) is a neuropsychiatric disorder characterized by childhood onset motor and phonic tics. In refractory cases, deep brain stimulation (DBS) with different targets including anteromedial Globus pallidus (AM-GPi) looks promising.

PATIENTS AND METHODS

Patients with TS diagnosed according to DSM-IV TR criteria with severe medication-recalcitrant disease referred to our DBS clinic, were recruited for this study. They underwent bilateral AM-GPi DBS with Model 3389, Medtronic electrodes. Patients were assessed using Yale Global Tic Severity Scale (YGTSS) and Gilles de la Touretts syndrome-quality of life (GTS-QOL) questionnaire before and one year after DBS.

RESULTS

Six patients (four men and two women) with severe medication-recalcitrant TS, mean age of 26.33 ± 7.25 years fulfilled the follow up visits. All patients revealed significant improvement in tics severity one year after surgery. Based on YGTSS, total tic severity score decreased from 75.66 ± 16.54 to 28.33 ± 13.95, P-value:0.005. Quality of life improved significantly after DBS (26.66 ± 20.65 before and 70.00 ± 17.88 one year after surgery, P-value:0.02).

CONCLUSIONS

Results of our study in accordance to previous ones suggest AM-GPi DBS as an effective and well-tolerated therapeutic modality for patients with medication refractory TS.

The effects of amantadine on traumatic brain injury outcome: a double-blind, randomized, controlled, clinical trial

INTRODUCTION

Amantadine, as a dopamine receptor agonist, may stimulate and help the recovery of the nervous system after traumatic brain injury (TBI).

METHODS

We performed this study as a double-blind, randomized, controlled clinical trial with target population including all patients with TBI who scored nine or lower on the Glasgow Coma Scale (GCS), admitted to our hospital between January 2013 and April 2014. The protocol included administration of the drug (placebo or amantadine) for 6 weeks and patient evaluation using the GCS and FOUR score on the first, third and seventh days after the drug was started. After 6 months from starting study drug, the patients were evaluated on the Mini-Mental State Examination, Glasgow Outcome Study, Disability Rating Scale and Karnofsky Performance Scale.

RESULTS

We included 40 patients in the study. The mean age of the patients was 36.77 ± 18.21. As an only important finding, the amantadine group registered an important rise between the first and the seventh day of study drug (∆GCS7-GCS1) with p-value = 0.044.

CONCLUSION

Based on our findings during the first week and the 6 months (since starting drug) follow-ups, prescribing amantadine did not lead to reportable effects on the patients' level of consciousness, memory, disability, cognition, mortality and performance.

Targeting CDK2 overcomes melanoma resistance against BRAF and Hsp90 inhibitors

Novel therapies are undergoing clinical trials, for example, the Hsp90 inhibitor, XL888, in combination with BRAF inhibitors for the treatment of therapy-resistant melanomas. Unfortunately, our data show that this combination elicits a heterogeneous response in a panel of melanoma cell lines including PDX-derived models. We sought to understand the mechanisms underlying the differential responses and suggest a patient stratification strategy. Thermal proteome profiling (TPP) identified the protein targets of XL888 in a pair of sensitive and unresponsive cell lines. Unbiased proteomics and phosphoproteomics analyses identified CDK2 as a driver of resistance to both BRAF and Hsp90 inhibitors and its expression is regulated by the transcription factor MITF upon XL888 treatment. The CDK2 inhibitor, dinaciclib, attenuated resistance to both classes of inhibitors and combinations thereof. Notably, we found that MITF expression correlates with CDK2 upregulation in patients; thus, dinaciclib would warrant consideration for treatment of patients unresponsive to BRAF-MEK and/or Hsp90 inhibitors and/or harboring MITF amplification/overexpression.

Silencing FLI or targeting CD13/ANPEP lead to dephosphorylation of EPHA2, a mediator of BRAF inhibitor resistance, and induce growth arrest or apoptosis in melanoma cells

A majority of patients with BRAF-mutated metastatic melanoma respond to therapy with BRAF inhibitors (BRAFi), but relapses are common owing to acquired resistance. To unravel BRAFi resistance mechanisms we have performed gene expression and mass spectrometry based proteome profiling of the sensitive parental A375 BRAF V600E-mutated human melanoma cell line and of daughter cell lines with induced BRAFi resistance. Increased expression of two novel resistance candidates, aminopeptidase-N (CD13/ANPEP) and ETS transcription factor FLI1 was observed in the BRAFi-resistant daughter cell lines. In addition, increased levels of the previously reported resistance mediators, receptor tyrosine kinase ephrine receptor A2 (EPHA2) and the hepatocyte growth factor receptor MET were also identified. The expression of these proteins was assessed in matched tumor samples from melanoma patients obtained before BRAFi and after disease progression. MET was overexpressed in all progression samples while the expression of the other candidates varied between the individual patients. Targeting CD13/ANPEP by a blocking antibody induced apoptosis in both parental A375- and BRAFi-resistant daughter cells as well as in melanoma cells with intrinsic BRAFi resistance and led to dephosphorylation of EPHA2 on S897, previously demonstrated to cause inhibition of the migratory capacity. AKT and RSK, both reported to induce EPHA2 S897 phosphorylation, were also dephosphorylated after inhibition of CD13/ANPEP. FLI1 silencing also caused decreases in EPHA2 S897 phosphorylation and in total MET protein expression. In addition, silencing of FLI1 sensitized the resistant cells to BRAFi. Furthermore, we show that BRAFi in combination with the multi kinase inhibitor dasatinib can abrogate BRAFi resistance and decrease both EPHA2 S897 phosphorylation and total FLI1 protein expression. This is the first report presenting CD13/ANPEP and FLI1 as important mediators of resistance to BRAF inhibition with potential as drug targets in BRAFi refractory melanoma.

PPAR-gamma in overcoming kinase resistance in chronic myeloid leukemia

Peroxisome proliferator-activated receptor gamma (PPARγ) plays key roles in regulating cellular differentiation, proliferation and apoptosis pathways. As such, they are considered promising targets for anticancer drug development, especially for breast cancer, multiple myeloma and hematologic malignancies. Chronic myeloid leukemia (CML) is a myeloproliferative disorder arising from an oncogenic Bcr-Abl tyrosine kinase. Inhibitors of this oncogene by small molecules such as imatinib are effective only in 75% of the patient's population. One of the potential strategies to overcome this resistance is to devise combination therapy protocols with other therapeutic agents including PPAR ligands. Since PPAR ligands are potentially interesting in different hematologic malignancies, this article will review the potential of PPAR ligands for use in CML treatment.

Molecular profiling of prostate cancer derived exosomes may reveal a predictive signature for response to docetaxel

Docetaxel is a cornerstone treatment for metastatic, castration resistant prostate cancer (CRPC) which remains a leading cause of cancer-related deaths, worldwide. The clinical usage of docetaxel has resulted in modest gains in survival, primarily due to the development of resistance. There are currently no clinical biomarkers available that predict whether a CRPC patient will respond or acquire resistance to this therapy. Comparative proteomics analysis of exosomes secreted from DU145 prostate cancer cells that are sensitive (DU145 Tax-Sen) or have acquired resistance (DU145 Tax-Res) to docetaxel, demonstrated significant differences in the amount of exosomes secreted and in their molecular composition. A panel of proteins was identified by proteomics to be differentially enriched in DU145 Tax-Res compared to DU145 Tax-Sen exosomes and was validated by western blotting. Importantly, we identified MDR-1, MDR-3, Endophilin-A2 and PABP4 that were enriched only in DU145 Tax-Res exosomes. We validated the presence of these proteins in the serum of a small cohort of patients. DU145 cells that have uptaken DU145 Tax-Res exosomes show properties of increased matrix degradation. In summary, exosomes derived from DU145 Tax-Res cells may be a valuable source of biomarkers for response to therapy.

The Effect of Prednisolone on miR 15a and miR16-1 Expression Levels and Apoptosis in Acute Lymphoblastic Leukemia Cell Line: CCRF-CEM

BACKGROUND

Glucocorticoids are probably the most important drugs in the treatment of childhood acute lymphoblastic leukemia (ALL). Prednisolone exerts its effect by induce apoptosis in lymphoid lineage cells. Micro RNAs are 18-24 nucleotides RNA implicated in the control of essential biological functions, including apoptosis. In the following study, the effect of prednisolone on the expression of miR 15a & miR16-1 and apoptosis in the CCRF-CEM cell line is investigated.

METHODS

The cell line of CCRF-CEM was cultured in standard conditions. The changes in the miR 15a and miR 16-1 expression levels were determined by Real Time-PCR technique. Also, the apoptosis is evaluated by flow cytometry using Annexin V and PI staining.

RESULTS

This study revealed that, the prednisolone induced apoptosis in a time dependent manner. Prednisolone in concentration of 700 µM was significantly increased the expression of miR 16-1 and miR 15a after 24 h and 48 h treatment (p<0.05).

CONCLUSION

prednisolone-induced apoptosis might be mediated by up-regulation of these 2 miRNAs in CCRF-CEM cells.

Abstract B28: PTENpg1 antisense RNA mediates PTEN suppression in vemurafenib resistance and predicts clinical outcome in melanoma patients

Approximately 50% of cutaneous melanomas carry activating mutations in the serine/threonine protein kinase BRAF. Vemurafenib is a highly potent inhibitor of BRAFV600E and prolongs survival in ~80% of melanoma patients carrying the mutation. Unfortunately, almost all patients develop resistance within 6-8 months of starting treatment. The molecular mechanism explaining this scenario is largely unclear, but loss of PTEN expression, has been suggested.

In this study we reveal a role for the PTEN pseudogene encoded antisense RNA (PTENpg1 asRNA) in epigenetic suppression of PTEN in melanoma cell lines resistant to vemurafenib. Resistant cell lines showed increased PTENpg1 asRNA expression while PTEN expression was suppressed. ChIP analysis showed enrichment of the histone modification enzyme EZH2 and subsequent enrichment of H3K27me3 at the PTEN promoter in the resistant cell line. Total cellular levels of EZH2, DNMT3a and H3k27me3 were, however, unaffected thus indicating specific recruitment of these factors to the PTEN promoter in the resistant cells by a mechanism that is dictated by the increased expression of PTENpg1 asRNA. In addition, we show that PTEN is reactivated by the depletion of EZH2 and DNMT3a and that this reactivation of PTEN re-sensitizes the cells to vemurafenib treatment.

Finally, we show that PTENpg1 asRNA could be a promising prognostic marker of clinical outcome of melanoma patients. PTENpg1 asRNA expression levels were measured in samples from patients that had not received any oncological treatment and were classified with stage III melanomas. We found that high PTENpg1 asRNA expression correlates with short-term survival in melanoma patients.

In conclusions, the PTENpg1 asRNA appears to be an important player in vemurafenib resistance and could be an attractive therapeutic target. In addition, PTENpg1 asRNA is potentially a promising prognostic marker for clinical outcome for melanoma patients.

Citation Format: Linda Vidarsdottir, Alireza Azimi, Jason Serviss, Christian Ingvar, Göran Jönsson, Håkan Olsson, Marianne Frostvik Stolt, Johan Hansson, Suzanne Egyházi Brage, Dan Grandér, Per Johnsson. PTENpg1 antisense RNA mediates PTEN suppression in vemurafenib resistance and predicts clinical outcome in melanoma patients. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr B28.

Proteomics analysis of melanoma metastases: association between S100A13 expression and chemotherapy resistance

BACKGROUND

Disseminated cutaneous malignant melanoma (CMM) is commonly unresponsive to standard chemotherapies, and there are as yet no predictive markers of therapy response.

METHODS

In the present study we collected fresh-frozen pretreatment lymph-node metastasis samples (n=14) from melanoma patients with differential response to dacarbazine (DTIC) or temozolomide (TMZ) chemotherapy, to identify proteins with an impact on treatment response. We performed quantitative protein profiling using tandem mass spectrometry and compared the proteome differences between responders (R) and non-responders (NR), matched for age, gender and histopathological type of CMM.

RESULTS

Biological pathway analyses showed several signalling pathways differing between R vs NR, including Rho signalling. Gene expression profiling data was available for a subset of the samples, and the results were compared with the proteomics data. Four proteins with differential expression between R and NR were selected for technical validation by immunoblotting (ISYNA1, F13A1, CSTB and S100A13), and CSTB and S100A13 were further validated on a larger sample set by immunohistochemistry (n=48). The calcium binding protein S100A13 was found to be significantly overexpressed in NR compared with R in all analyses performed.

CONCLUSIONS

Our results suggest that S100A13 is involved in CMM resistance to DTIC/TMZ.

Differentiation of human endometrial stem cells into urothelial cells on a three-dimensional nanofibrous silk-collagen scaffold: an autologous cell resource for reconstruction of the urinary bladder wall

Reconstruction of the bladder wall via in vitro differentiated stem cells on an appropriate scaffold could be used in such conditions as cancer and neurogenic urinary bladder. This study aimed to examine the potential of human endometrial stem cells (EnSCs) to form urinary bladder epithelial cells (urothelium) on nanofibrous silk-collagen scaffolds, for construction of the urinary bladder wall. After passage 4, EnSCs were induced by keratinocyte growth factor (KGF) and epidermal growth factor (EGF) and seeded on electrospun collagen-V, silk and silk-collagen nanofibres. Later we tested urothelium-specific genes and proteins (uroplakin-Ia, uroplakin-Ib, uroplakin-II, uroplakin-III and cytokeratin 20) by immunocytochemistry, RT-PCR and western blot analyses. Scanning electron microscopy (SEM) and histology were used to detect cell-matrix interactions. DMEM/F12 supplemented by KGF and EGF induced EnSCs to express urothelial cell-specific genes and proteins. Either collagen, silk or silk-collagen scaffolds promoted cell proliferation. The nanofibrous silk-collagen scaffolds provided a three-dimensional (3D) structure to maximize cell-matrix penetration and increase differentiation of the EnSCs. Human EnSCs seeded on 3D nanofibrous silk-collagen scaffolds and differentiated to urothelial cells provide a suitable source for potential use in bladder wall reconstruction in women.

Sex-dependent hepatic transcripts and metabolites in the development of glucose intolerance and insulin resistance in Zucker diabetic fatty rats

Male Zucker diabetic fatty (mZDF) rats spontaneously develop type 2 diabetes, whereas females only become diabetic when fed a diabetogenic high-fat diet (high-fat-fed female ZDF rat, HF-fZDF). The aim of this study was to investigate if differences in liver functions could provide clues to this sex difference. Non-diabetic obese fZDF rats were compared with either mZDF or HF-fZDF regarding hepatic molecular profiles, to single out those components that might be protective in the females. High-fat feeding in fZDF led to enhanced weight gain, increased blood glucose and insulin levels, reduced insulin sensitivity and a trend towards reduced glucose tolerance, indicative of a prediabetic state. mZDF rats were diabetic, with low levels of insulin, high levels of glucose, reduced insulin sensitivity and impaired glucose tolerance. Transcript profiling and capillary electrophoresis time-of-flight mass spectrometry were used to indentify hepatic transcripts and metabolites that might be related to this. Many diet-induced alterations in transcript and metabolite levels in female rats were towards a 'male-like' phenotype, including reduced lipogenesis, increased fatty acid (FA) oxidation and increased oxidative stress responses. Alterations detected at the level of hepatic metabolites, indicated lower capacity for glutathione (GSH) production in male rats, and higher GSH turnover in females. Taken together, this could be interpreted as if anabolic pathways involving lipogenesis and lipid output might limit the degree of FA oxidation and oxidative stress in female rats. Together with a greater capacity to produce GSH, these hepatic sex differences might contribute to the sex-different development of diabetes in ZDF rats.

Abstract 3495: Targeted therapies in melanoma – in vitro effects of single and combined drug treatment

Malignant melanoma is one of the most rapidly increasing malignancies in Caucasian populations. So far, curative treatment is achieved only by surgical resection at an early stage, while the prognosis in cases with disseminated melanoma is poor, and we lack predictive tools to identify the few patients who respond to existing chemotherapy. Promising clinical trials of targeted therapies are ongoing, however, it is already clear that drug resistance will be a clinical reality also for these new therapies. Thus, novel predictive markers are urgently needed to identify responders to different types of therapy in melanoma.

The aim of the study is to unravel molecular mechanisms and pathways underlying resistance to new therapies in melanoma.

We are studying the effects of a set of MAPK and PI3K pathways inhibitors in melanoma cell lines that are wildtype or have different mutations/deletions in genes affecting these pathways (BRAF, NRAS, PTEN etc.). Cells are exposed to single drugs as well as combinations of inhibitors and/or chemotherapeutic agents.

Our results have shown that there is a wide range of sensitivity to the BRAF inhibitor PLX4720 among BRAF mutated cell lines, with IC50 values varying from 0.3 µM to 30 µM. We are investigating the underlying mechanisms causing this variation in sensitivity to the drug. Using gene expression profiling of a clinical material, we have identified several candidate genes that may predict response to DNA alkylating agents dacarbazine and temozolomide. The expression of some of these genes can be affected by PLX4720, and their potential relevance for response to different treatments is currently tested in vitro.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3495. doi:10.1158/1538-7445.AM2011-3495

Simultaneous pattern visual evoked potential and pattern electroretinogram in strabismic and anisometropic amblyopia

BACKGROUND

Amblyopia is a relatively common condition in which visual acuity through an eye is subnormal despite no overt pathology. Pattern visual evoked potential (PVEP) can detect any defect from optic nerve to occipital cortex and pattern electroretinogram (PERG) can detect retinal defects specially the ganglion layers. This study was performed to evaluate the cortical and retinal activity in strabismic and anisometropic amblyopia.

METHODS

PVEP and PERG were recorded simultaneously in 40 amblyopes (20 strabismics and 20 anisometropics) and 20 normal control subjects. Normal subjects were age and sex matched with patients.

RESULTS

The P(100) latency in PVEP was increased in both groups of patients but the P(100) amplitude was reduced only in anisometropic group. In PERG, the amplitude of P(50) was reduced in all patients with no significant change in latency.

CONCLUSION

Beside reduced PVEP responses in strabismic and anisometropic amblyopia, the activity of retina reduced too. It is likely that retinal impulses can affect the development of visual system.