Impact of neonatal anoxia and hypothermic treatment on development and memory of rats

Therapeutic hypothermia (TH) is well established as a standard treatment for term and near-term infants. However, therapeutic effects of hypothermia following neonatal anoxia in very premature babies remains inconclusive. The present rodent model of preterm neonatal anoxia has been shown to alter developmental milestones and hippocampal neurogenesis, and to disrupt spatial learning and memory in adulthood. These effects seem to be reduced by post-insult hypothermia. Epigenetic-related mechanisms have been postulated as valuable tools for developing new therapies. Dentate gyrus neurogenesis is regulated by epigenetic factors. This study evaluated whether TH effects in a rodent model of preterm oxygen deprivation are based on epigenetic alterations. The effects of TH on both developmental features (somatic growth, maturation of physical characteristics and early neurological reflexes) and performance of behavioral tasks at adulthood (spatial reference and working memory, and fear conditioning) were investigated in association with the possible involvement of the epigenetic operator Enhancer of zeste homolog 2 (Ezh2), possibly related to long-lasting effects on hippocampal neurogenesis. Results showed that TH reduced both anoxia-induced hippocampal neurodegeneration and anoxia-induced impairments on risk assessment behavior, acquisition of spatial memory, and extinction of auditory and contextual fear conditioning. In contrast, TH did not prevent developmental alterations caused by neonatal anoxia and did not restore hippocampal neurogenesis or cause changes in EZH2 levels. In conclusion, despite the beneficial effects of TH in hippocampal neurodegeneration and in reversing disruption of performance of behavioral tasks following oxygen deprivation in prematurity, these effects seem not related to developmental alterations and hippocampal neurogenesis and, apparently, is not caused by Ezh2-mediated epigenetic alteration.

Epigenetic regulation of retinal development

In the developing vertebrate retina, retinal progenitor cells (RPCs) proliferate and give rise to terminally differentiated neurons with exquisite spatio-temporal precision. Lineage commitment, fate determination and terminal differentiation are controlled by intricate crosstalk between the genome and epigenome. Indeed, epigenetic regulation plays pivotal roles in numerous cell fate specification and differentiation events in the retina. Moreover, aberrant chromatin structure can contribute to developmental disorders and retinal pathologies. In this review, we highlight recent advances in our understanding of epigenetic regulation in the retina. We also provide insight into several aspects of epigenetic-related regulation that should be investigated in future studies of retinal development and disease. Importantly, focusing on these mechanisms could contribute to the development of novel treatment strategies targeting a variety of retinal disorders.

Mitochondria-ER Tethering in Neurodegenerative Diseases

Organelles juxtaposition has been detected for decades, although only recently gained importance due to a pivotal role in the regulation of cellular processes dependent on membrane contact sites. Endoplasmic reticulum (ER) and mitochondria interaction is a prime example of organelles contact sites. Mitochondria-associated membranes (MAM) are proposed to harbor ER-mitochondria tether complexes, mainly when these organelles are less than 30 nm apart. Dysfunctions of proteins located at the MAM are associated with neurodegenerative diseases such as Parkinson's, Alzheimer's and amyotrophic lateral sclerosis, as well as neurodevelopmental disorders; hence any malfunction in MAM can potentially trigger cell death. This review will focus on the role of ER-mitochondria contact sites, regarding calcium homeostasis, lipid metabolism, autophagy, morphology and dynamics of mitochondria, mainly in the context of neurodegenerative diseases. Approaches that have been employed so far to study organelles contact sites, as well as methods that were not used in neurosciences yet, but are promising and accurate ways to unveil the functions of MAM during neurodegeneration, is also discussed in the present review.

Focused ultrasound as a novel strategy for noninvasive gene delivery to retinal Müller glia

Müller glia are specialized retinal cells with stem cell properties in fish and frogs but not in mammals. Current efforts to develop gene therapies to activate mammalian Müller glia for retinal repair will require safe and effective delivery strategies for recombinant adeno-associated viruses (AAVs), vectors of choice for clinical translation. Intravitreal and subretinal injections are currently used for AAV gene delivery in the eye, but less invasive methods efficiently targeting Müller glia have yet to be developed. Methods: As gene delivery strategies have been more extensively studied in the brain, to validate our vectors, we initially compared the glial tropism of AAV-PHP.eB, an AAV9 that crosses the blood-brain and blood-retinal barriers, for its ability to drive fluorescent protein expression in glial cells in both the brain and retina. We then tested the glial transduction of AAV2/8-GFAP-mCherry, a virus that does not cross blood-brain and blood-retinal barriers, for its effectiveness in transducing Müller glia in murine retinal explants ex vivo. For in vivo assays we used larger rat eyes, performing invasive intravitreal injections, and non-invasive intravenous delivery using focused ultrasound (FUS) (pressure amplitude: 0.360 - 0.84 MPa) and microbubbles (Definity, 0.2 ml/kg). Results: We showed that AAV-PHP.eB carrying a ubiquitous promoter (CAG) and green fluorescent protein (GFP) reporter, readily crossed the blood-brain and blood-retinal barriers after intravenous delivery in mice. However, murine Müller glia did not express GFP, suggesting that they were not transduced by AAV-PHP.eB. We thus tested an AAV2/8 variant, which was selected based on its safety record in multiple clinical trials, adding a glial fibrillary acidic protein (GFAP) promoter and mCherry (red fluorescent protein) reporter. We confirmed the glial specificity of AAV2/8-GFAP-mCherry, showing effective expression of mCherry in astrocytes after intracranial injection in the mouse brain, and of Müller glia in murine retinal explants. For in vivo experiments we switched to rats because of their larger size, injecting AAV2/8-GFAP-mCherry intravitreally, an invasive procedure, demonstrating passage across the inner limiting membrane, leading to Müller glia transduction. We then tested an alternative non-invasive delivery approach targeting a different barrier - the inner blood-retinal-barrier, applying focused ultrasound (FUS) to the retina after intravenous injection of AAV2/8 and microbubbles in rats, using magnetic resonance imaging (MRI) for FUS targeting. FUS permeabilized the rat blood-retinal-barrier and allowed the passage of macromolecules to the retina (Evans blue, IgG, IgM), with minimal extravasation of platelets and red blood cells. Intravenous injection of microbubbles and AAV2/8-GFAP-mCherry followed by FUS resulted in mCherry expression in rat Müller glia. However, systemic delivery of AAV2/8 also had off-target effects, transducing several murine peripheral organs, particularly the liver. Conclusions: Retinal permeabilisation via FUS in the presence of microbubbles is effective for delivering AAV2/8 across the inner blood-retinal-barrier, targeting Müller glia, which is less invasive than intravitreal injections that bypass the inner limiting membrane. However, implementing FUS in the clinic will require a comprehensive consideration of any off-target tropism of the AAV in peripheral organs, combined ideally, with the development of Müller glia-specific promoters.

Tissue-specific somatic stem-cell isolation and characterization from human endometriosis. Key roles in the initiation of endometrial proliferative disorders

AIM

The endometrial-proliferation related diseases leads to endometrial hyperplasia, i.e., endometriosis. Endometrial progenitor and stem cells play key roles in the beginning of endometrial proliferative disorders. The purpose of this study was the isolation of stem cells in the endometriosis lesion as well as the evaluation and comparison of the stemness-related target genes in endometriosis endometrial stem cells (EESCs), normal endometrial stem cell (ESCs), endometrial lesions stem cell (ELSCs) and bone marrow mesenchymal stem cells (MSCs).

METHODS

EESCs, ESCs, ELSCs and MSCs were isolated. Flowcytometry and real-time PCR were utilized to detect the cell surface marker and expression pattern of 16 stemness genes. The proliferation of all stem cells was observed by MTT assay. The differentiation potential was evaluated by alizarin red, oil red O and RT-PCR method. The karyotyping was performed on EESCs and ELSCs at passage 20.

RESULTS

The unique patterns of gene expression were detected although EESCs, ESCs, ELSCs and MSCs have a background expression of stemness-related genes. Spindle-like morphology, normal karyotype, adipogenic and osteogenic potential, significantly expression of Oct4, SALL4, DPPA2, Sox2, Sox17 and also specific surface markers such as CD44, CD105, CD90, CD73 and CD146 in EESCs and ELSCs was observed.

CONCLUSION

According to our data, stem cells in endometriosis endometrial and endometriosis are such a informative tools to study of pathogenesis of gynecological diseases. Furthermore, endometrial stem/progenitor cells which easily obtain from tissue may be valuable targets for early diagnosis of endometrial disorders in the future.

Aberrant expression of DPPA2 and HIWI genes in colorectal cancer and their impacts on poor prognosis

Cancer cells have countless behaviors of pluripotent embryonic stem cells and germ line cells, such as unlimited proliferation, self-renewal, and migration. Expression of specific germ line and embryonic genes in tumor cells may be associated with indefinite growth and invasiveness of such cells. Developmental pluripotency factor 2 (DPPA2) and HIWI are two important developmental genes which are involved in embryonic and germ line stem cell properties. Deciphering the role of these genes seems to be necessary for understanding cancer initiation and progression. Tumoral and normal tissues from 46 colorectal cancer (CRC) patients were subjected to gene expression analysis using quantitative real-time reverse transcription-polymerase chain reaction, prior to any therapeutic intervention. Overexpression of DPPA2 and HIWI was detected in 26.1 and 34.8 % of specimens, respectively. Significant correlation between DPPA2 overexpression and lymph node metastasis of the tumor cells (P=0.049) was seen in the samples with advanced stages (III/IV) of the tumor development. HIWI mRNA expression was significantly associated to the depth of tumor invasion (P=0.020) and the stage of tumorigenesis progression (P=0.030). In samples with overexpression of at least one gene, DPPA2 mRNA expression was significantly correlated to the stage of tumor (P=0.017). In the same samples, a significant correlation was observed between mRNA expression of HIWI and the stage of tumor cells (P=0.034). These results documented the important role of HIWI and DPPA2 in tumorigenesis and also in lymph node metastasis of tumor cells. Further evaluation is required to uncover the detailed role of HIWI and DPPA2 and their interactions in tumorigenesis of CRC.

Association of PYGO2 and EGFR in esophageal squamous cell carcinoma

Wnt signaling is an important evolutionary conserved pathway that is not only involved in determination of cellular development, self-renewal, and fate, but also has significant roles in tumor development and progression. Deregulation of the Wnt/β-catenin signaling pathway and aberrant expression of its components is commonly observed in solid tumors. Such aberrant regulation of Wnt signaling is commonly related to either malfunction of its components or crosstalk with other cellular processes such as the epidermal growth factor receptor (EGFR) signaling cascade. Therefore, identification of the roles of major involved components may be useful to identify new therapeutic targets for cancer treatment. In this study, we assessed EGFR and PYGO2 mRNA expression in tumors and margin normal tissues from 55 esophageal squamous cell carcinoma (ESCC) patients using real-time qRT-PCR, and evaluated clinicopathology relative to the two genes' expression levels. Significant PYGO2 and EGFR overexpression was observed in 30.9 % (P = 0.017) and 38.2 % (P = 0.006) of tumors, respectively. PYGO2 and EGFR expression were significantly associated not only with each other (P < 0.001), but also with tumor staging and depth (P < 0.001). Furthermore, PYGO2 expression was significantly correlated with the tumor grade (P = 0.043) and size (P = 0.023). We identify PYGO2 as a new molecular marker of invasive tumors, introducing its probable oncogenic role in ESCC progression and aggressiveness. In line with other reports, we also illustrate the oncogenic function of EGFR in the development of ESCC through advance stages. We also observed a significant correlation between PYGO2 and EGFR in ESCC tumors, which reveals a mutual convergent influence of these factors in tumor progression and development. Considering aberrant expression, mutual positive feedback, and the significant clinical relevance of these genes in ESCC, we introduce them as appropriate therapeutic targets in adjuvant therapy of ESCC.

Role of SALL4 in the progression and metastasis of colorectal cancer

Background

Human cancer cells resemble stem cells in expression signatures leading them to share some features, most notably, self-renewal. A complex network of transcription factors and signaling molecules are required for continuance of this trait. SALL4 is a zinc finger transcriptional activator crucial for maintenance of self-renewal in stem cells; however, its expression level has not yet been elucidated in colorectal tumor cells. To determine this level and probable clinicopathological consequences, its expression was analyzed.

Methods

SALL4 expression in fresh tumoral and distant tumor-free tissues from 46 colorectal samples was compared by real-time polymerase chain reaction (PCR).

Results

Greater than a two-fold increase in SALL4 expression was detected in 87% of tumors vs. normal related tissues. SALL4 expression was significantly correlated with tumor cell metastasis to lymph nodes, especially in moderately-differentiated tumor samples (P < 0.05). Furthermore, higher levels of SALL4 mRNA expression were significantly associated with younger than older patients with tumor cells in stages I and II (P < 0.05).

Conclusions

These results indicate a relationship between SALL4 expression and tumor cell metastasis to lymph nodes and consequent advancement of tumors to advanced stages III and IV. Along with the promising evidence of its role in self-renewal in various cancers, SALL4 may have a role in progression, development and maintenance of colorectal cancers.

High frequency of microsatellite instability in sporadic colorectal cancer patients in Iran

Microsatellite instability in sporadic colorectal cancer patients was assessed, and the clinicopathological associations were evaluated in northeastern Iran, which is a high-risk region for gastrointestinal malignancies. Microsatellite instability (MSI) status of tumoral tissue, compared to normal tissue, was assessed with a standard panel of MSI markers on paraffin-embedded surgically resected tissues from 67 consecutive sporadic colorectal cancer patients. Eleven of the patients were under 40 years old. Female patients were significantly younger than male patients (mean age 54.2 vs 62.1 years, P = 0.020). MSI analysis revealed 18 cases of MSI-H (26.9%), 11 MSI-L (16.4%) and 38 MSS (microsatellite stable tumors; 56.7%). While a greater proportion of patients consisted of males, 56.7 vs 43.3% females, MSI-H was more frequent in females (34.5 vs 21.5%). MSI was associated with proximal location of tumor (P = 0.003) and lower stages of tumor (P = 0.002), while MSS tumors were associated with node metastasis. MSI has a higher frequency in sporadic colorectal cancer patients, suggesting that molecular epidemiology of the genetic alterations involved in colorectal cancer carcinogenesis has a different pattern in the Iranian population, which deserves further epidemiological attention. The high frequency of MSI-H in this population suggests that we should look at microsatellite instability prior to chemotherapy to determine the most appropriate chemotherapeutic strategy in our population.

Expression analysis elucidates the roles of MAML1 and Twist1 in esophageal squamous cell carcinoma aggressiveness and metastasis

BACKGROUND

Epithelial-mesenchymal transition has recently attracted great attention in studying the malignant progression of cells through a converging pathway of oncogenesis and metastasis. Twist1 and Mastermind-like 1 (MAML1) are major regulators of EMT through different pathways. The aim of this study was to investigate the clinicopathological relevance of the expression of MAML-1 and Twist1 genes in esophageal squamous cell carcinoma (ESCC).

METHODS

Tumoral and corresponding normal tissues from 55 treatment-naive ESCC patients were subjected for expression analysis with quantitative real-time RT-PCR.

RESULTS

Overexpression of MAML-1 and Twist1 were significantly associated with lymph node metastasis and the surgical staging of tumor. Overexpression of Twist1 was associated with tumor depth of invasion. Mean relative expression (MRE) of MAML1 was significantly higher in patients with metastasis to lymph nodes (3.07 ± 0.51 vs. 0.86 ± 0.58, P = .008). MRE of Twist1 was significantly higher in patients with invasion of tumor to adventitia (T3, T4) (1.97 ± 0.29 vs. 0.39 ± 0.73, P = .036). In advanced stages of tumor (stage III, IV), a significantly higher MRE of Twist1 (2.47 ± 0.41 vs. 1.25 ± 0.36, P = .035) and MAML1 (3.05 ± 0.45 vs. 1.07 ± 0.59, P = .021) mRNA was observed.

CONCLUSIONS

We introduce Twist1 and MAML1 as new molecular markers of advanced tumor, which determine the characteristics and aggressive behavior of ESCC. Along with the emerging evidence of their role in different cellular processes and aberrations in various cancers, they are suggested as potentially interesting therapeutic targets to reverse a broad spectrum of functional aberrations that promote ESCC development.

Quantitative analysis of TEM-8 and CEA tumor markers indicating free tumor cells in the peripheral blood of colorectal cancer patients

BACKGROUND

Colorectal cancer (CRC) remains the third most common cancer in the world. Approximately in 50 percent of patients, metastatic disease is a major cause of death. Therefore, early diagnosis of CRC is crucial for a successful outcome. For the detection of circulating cancer cells, this study applied a sensitive method that employed specific tumor markers for early detection.

METHODS

A total of 80 blood samples from 40 CRC patients and 40 age-matched healthy controls were collected for the study. The circulating mRNA levels of two CRC tumor markers, tumor endothelial marker 8 (TEM-8) and carcinoembryogenic antigen (CEA) were evaluated using an absolute quantitative real-time PCR assay in a Stratagene Mx-3000P real-time PCR system. GAPDH was used as the endogenous control.

RESULTS

TEM-8 and CEA were primarily detected more in the CRC patients rather than in the controls: 22/40 vs 9/40, p=0.009 and 30/40 vs 11/40, p=0.00054, respectively. In the CRC patients, the mRNA level of these markers was significantly higher in comparison to the normal controls (p=0.018 and 0.01). The overall sensitivity of this panel was 65% with a specificity of 75%. Statistical analysis for demographic variants did not reach significant values.

CONCLUSIONS

TEM-8 and CEA markers were detected more frequently and in significantly higher levels in the blood samples of patients compared with samples from age-matched healthy controls. The copy number of CEA and TEM-8 mRNA, as detected by a real-time quantitative PCR, appears to be a promising marker for evaluating the risk of tumor spread.

Cancer-testis gene expression profiling in esophageal squamous cell carcinoma: identification of specific tumor marker and potential targets for immunotherapy

Cancer-testis antigens (CTAs) are often specifically expressed in cancer cells and under normal conditions are only considered to be expressed in the germ line cells and the placenta. CTAs are potential targets for cancer immunotherapy and therefore necessitates their expression profiling. The expression profile of LAGE1, MAGE-A4 and NY-ESO1, their possible correlations and interaction, and the clinicopathological associations of each marker were studied. RNA was extracted from fresh esophagectomy tissues of 41 esophageal squamous cell carcinoma (ESCC) patients prior to any other therapeutic intervention. The relative mRNA expression of LAGE1, MAGE-A4 and NY-ESO1 was assessed with the real-time reverse transcription-polymerase chain reaction (RT-PCR) 5' nuclease assay. The overexpression of LAGE1, MAGE-A4 and NY-ESO1 was found in 39, 90.2 and 41.4% of ESCC samples respectively. Of the patients, 97.5% showed an overexpression of at least one CTA. The relative expression of MAGE-A4 was directly associated with lymph node metastasis and the stage of the tumor (p < 0.05). A significant direct correlation was also detected between the MAGE-A4/LAGE1 and MAGE-A4/NY-ESO1 levels of gene expression. MAGE-A4 is identified as a specific biomarker of ESCC with a possible oncogenic role contributing to tumor progression. Interactions between MAGE-A4, LAGE1 and NY-ESO1 and their significant clinical consequences introduce these CTAs as appropriate targets for a polyvalent cancer vaccine.