Elevated TrkA receptor expression is associated with all-trans retinoic acid-induced neuroblastoma differentiation

Neuroblastoma is the most common and one of the deadliest among pediatric tumors; however, a subset of infants with neuroblastoma display spontaneous regression. The mechanism of spontaneous regression remains to be elucidated. TrkA plays an essential role in the differentiation and functionality of neurons; abundant TrkA expression is associated with favorable prognosis of neuroblastoma. All-trans retinoic acid (ATRA), a first-line drug for acute promyelocytic leukemia (APL) treatment, has been shown to induce differentiation and inhibit cell growth. Neuroblastoma tissues in our hospital inpatient were collected, primary cell culture was performed, and the cells were separated and purified to be cell line. Trypan blue exclusion was used to count the numbers of cells alive, morphological changes were observed under the phase-contrast microscope. RT-PCR was used to determine the expression level of TrkA. In this study, a human neuroblastoma cell line was successfully established; in addition, we demonstrated that ATRA induces growth arrest and promotes the differentiation of neuroblastoma cells. In addition, ATRA was shown to significantly increase the levels of TrkA mRNA expression. Therefore, we concluded that the elevated expression of the TrkA receptor is associated with ATRA-induced growth arrest and differentiation o neuroblastoma cells. The results of this study provide a theoretical basis for the clinical application of differentiation-inducing ATRA for neuroblastoma therapy.

Long-term efficacy of sitagliptin as either monotherapy or add-on therapy to metformin: improvement in glycemic control over 2 years in patients with type 2 diabetes

OBJECTIVE

To evaluate the efficacy of once daily sitagliptin 100 mg as monotherapy or as add-on to metformin in patients with type 2 diabetes mellitus (T2DM) over 2 years of treatment.

RESEARCH DESIGN AND METHODS

The monotherapy analysis used pooled 104 week data from 64 patients in two randomized, double-blind trials evaluating the safety and efficacy of sitagliptin monotherapy. Data used were from patients who were randomized to sitagliptin 100 mg/day, were not on an antihyperglycemic agent at the screening visit, had baseline A1C of 7.0%-10.0%, and had Week 104 A1C measurements. The add-on to metformin analysis used pooled data from 347 patients in two randomized double-blind trials evaluating the safety and efficacy of sitagliptin + metformin combination therapy. Data used were from patients who were randomized to sitagliptin 100 mg/day + metformin ≥1500 mg/day, had baseline A1C of 7%-10%, and had Week 104 A1C measurements. Excluded from either analysis were patients who discontinued prior to 2 years (e.g., due to lack of efficacy, a need for rescue medications, or adverse experiences). Analysis endpoints were A1C, fasting plasma glucose (FPG), HOMA-β, proinsulin/insulin (P/I) ratio, and for monotherapy, 2 hour post-meal plasma glucose (PMG).

RESULTS

For the pooled monotherapy cohort, after 2 years of treatment, mean A1C, FPG, and 2 hour PMG decreased from baseline values of 7.9%, 156 mg/dL, and 223 mg/dL to 6.9%, 143 mg/dL, and 191 mg/dL, respectively, while HOMA-β increased from 67% to 85% and P/I ratio improved from 0.57 to 0.28. For the pooled add-on to metformin cohort, after 2 years of treatment, mean A1C and FPG decreased from baseline values of 7.7% and 160 mg/dL to 6.9% and 140 mg/dL, respectively, while HOMA-β increased from 50% to 62% and P/I ratio improved from 0.33 to 0.28. These analyses are limited in that only patients who were able to complete 104 weeks of study were included.

CONCLUSION

In the subset of patients with T2DM who maintained and completed treatment for 2 years with sitagliptin as monotherapy or as add-on to metformin, improvements in glycemic control and measures of β-cell function were observed over the course of treatment.

Reverse-dipper pattern of blood pressure may predict lacunar infarction in patients with essential hypertension

BACKGROUND AND PURPOSE

The fluctuation of circadian blood pressure (BP) is of great diversity in patients with essential hypertension and may provide significant prognostic value for stroke. However, it remains uncertain whether reverse-dipper pattern of BP influences the incidence of lacunar infarction in hypertensive patients.

METHODS

In the current study, 362 hypertensive patients (195 males, 167 females) were enrolled. BP patterns were evaluated with 24-h ambulatory BP monitoring (ABPM). Multinomial logistic regression was applied to analyse the possible relationships between lacunar infarction and various clinical risk factors such as ABPM.

RESULTS

A total of 93 patients (25.7%) had reverse-dipper BP pattern. Non-dipper pattern of BP was observed in 179 hypertensive patients (49.4%) and dipper pattern in 90 patients (24.9%). The percentage of lacunar infarction was the highest in the patients with reverse-dipper pattern compared with pure hypertension or atherothrombotic cerebral infarction (P < 0.05). After multinomial logistic regression analysis, reverse-dipper pattern of BP (odds ratio 2.492; 95% confidence interval 1.133-5.479; P < 0.05) and age (odds ratio 1.084; 95% confidence interval 1.047-1.123; P < 0.01) were found to be directly associated with lacunar infarction.

CONCLUSIONS

Reverse-dipper BP pattern may serve as an independent risk factor for lacunar infarction and more personalized BP management should be offered to the patients who have elevated nocturnal BP.

Bosentan protects the spinal cord from ischemia reperfusion injury in rats through vascular endothelial growth factor receptors

STUDY DESIGN

Experimental study.

OBJECTIVES

To investigate whether Bosentan, an endothelin-A/-B dual receptor antagonist, could protect neurons after spinal cord ischemia reperfusion (SCIR) injury in rats and its underlying signaling pathway.

SETTING

Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi Province, China.

METHODS

Sprague-Dawley rats were randomly divided into two groups, saline group (IRS, n=48) and Bosentan group (IRB, 5 mg kg(-1), n=48). After ischemia for 1 h with occlusion of the infrarenal aorta, spinal cord were reperfused for 6h, 12h, 24h, 3d, 5d, and 7d separately. Enzyme-linked immunosorbent assay was used to detect vascular endothelial growth factor (VEGF) in serum. Immunohistochemistry was performed to detect protein expression of VEGF, VEGF receptor 1 (FLT-1) and VEGF receptor 2 (FLK-1). Gene expressions of VEGF and its receptors were evaluated using the quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with the IRS group, gene and protein expressions of VEGF, FLT-1 and FLK-1 were significantly increased (P<0.05), so was the concentration of VEGF in plasma (P<0.05). FLK-1 was expressed on spinal cord neurons.

Knockdown of IGF2R suppresses proliferation and induces apoptosis in hemangioma cells in vitro and in vivo

Insulin-like growth factor-II (IGF-II)/IGF2R signaling plays a pivotal role in cell growth, migration and differentiation in many malignancies. An individual with high IGF-II expression levels has a high risk of developing cancer, but IGF2R is often considered to be a tumor suppressor. To date, little has been reported about the role of IGF-II/IGF2R signaling in hemangiomas (HAs). Thus, uncovering the mechanisms of IGF-II/IGF2R signaling is very important to understanding the development of HAs. In the present study, the expression of IGF-II and IGF2R was investigated in 27 cases of HAs of different phases by immunohistochemistry. Through lentivirus-mediated IGF2R siRNA (Lv-siIGF2R) in HA-derived endothelial cells (HDECs), we observed the effects of IGF2R knockdown on the biological behavior of HA cells. We found that the expression of IGF-II and IGF2R was significantly increased in proliferating phase HAs, but decreased in involuting phase HAs. Furthermore, knockdown of IGF2R in vitro significantly diminished the proliferative activity and induced apoptosis and cycle arrest with decreased expression of PCNA, Ki-67, Bcl-2, Cyclin D1 and E and increased the expression of Bax in the proliferative phase HAs (HDEC and CRL-2586 EOMA cells). In addition, the tumor volumes in a subcutaneous HDEC nude mouse model treated with Lv-siIGF2R were significantly smaller than those of the control group. Taken together, our findings indicate that the expression of IGF-II and IGF2R is increased in proliferating phase HAs, and knockdown of IGF2R suppresses proliferation and induces apoptosis in HA cells in vitro and in vivo, suggesting that IGF2R may represent a novel therapeutic target for the treatment of human HAs.

A 12-week subchronic intramuscular toxicity study of risperidone-loaded microspheres in rats

Long-acting injectable formulations of antipsychotics have been an important treatment option to increase the compliance of the patient with schizophrenia by monitoring drug administration and identifying medication noncompliance and to improve the long-term management of schizophrenia. Risperidone, a serotoninergic 5-HT2 and dopaminergic D2 receptor antagonist, was developed to be a long-acting sustained-release formulation for the treatment of schizophrenia. In this study, 12-week subchronic toxicity study of risperidone-loaded microspheres (RMs) in rats by intramuscular injection with an 8-week recovery phase was carried out to investigate the potential subchronic toxicity of a novel long-acting sustained-release formulation. The results indicated that the dosage of 10-90 mg/kg of RM for 2 weeks did not cause treatment-related mortality. The main drug-related findings were contributed to the dopamine D2 receptor and α1-adrenoceptor antagonism of risperidone such as elevation of serum and pituitary prolactin levels and ptosis and changes in reproductive system (uterus, ovary, vagina, mammary gland, testis, seminal vesicle, epididymis, and prostate). In addition, foreign body granuloma in muscle at injection sites caused by poly-lactide-co-glycolide was observed. At the end of the recovery phase, these changes mostly returned to normal. The results indicated that RM had a good safety profile in rats.

Relative filling time delay based on CT perfusion source imaging: a simple method to predict outcome in acute ischemic stroke

BACKGROUND AND PURPOSE

Collateral vessel status is strongly associated with clinical outcome in ischemic stroke but can be challenging to assess. The aim of this study was to develop a tomography perfusion source imaging-based assessment of collateral vessel status.

MATERIALS AND METHODS

Consecutive patients with ischemic stroke who received intravenous thrombolysis or intra-arterial reperfusion therapy after CTP were retrospectively analyzed. In those with middle cerebral artery or internal carotid artery occlusion, CT perfusion source imaging was used to identify the relative filling time delay between the normal MCA Sylvian branches and those in the affected hemisphere. Receiver operating characteristic analysis and logistic regression were used to assess the association of the relative filling time delay with the 24-hour Alberta Stroke Program Early CT Score based on noncontrast CT and the 90-day modified Rankin Scale score.

RESULTS

There were 217 patients treated in 2009-2011 who had CTP data, of whom 60 had MCA or ICA occlusion and 55 had 90-day mRS data. The intraclass correlation coefficient for relative filling time delay was 0.95. Relative filling time delay was correlated with 24-hour ASPECTS (Spearman ρ=-0.674; P<.001) and 90-day mRS score (ρ=0.516, P<.01). Increased relative filling time delay was associated with poor radiologic outcome (ASPECTS, 0-7) (area under the curve=0.79, P<.001) and poor functional outcome (mRS score, 3-6) (area under the curve=0.77, P=.001). In multivariate logistic regression, the association of longer relative filling time delay with poor outcome remained significant, independent of age, sex, and baseline National Institutes of Health Stroke Scale score.

CONCLUSIONS

Relative filling time delay is a useful independent predictor of clinical outcome after ischemic stroke.

CD58, a novel surface marker, promotes self-renewal of tumor-initiating cells in colorectal cancer

Colorectal tumor-initiating cells (CT-ICs) have self-renewal capabilities and have an important role in tumorigenesis, metastasis, recurrence and treatment resistance in colorectal cancer. Multiple cell-surface molecules targeting CT-ICs, possibly representing different CT-IC subpopulations, have been reported. However, whether new surface markers exist, as well as the mechanisms by which the markers regulate self-renewal, remain unclear. In this study, we enriched a CT-IC population through a serum-free low-adhesion system in vitro. Within this population, we found that CD58 and CD44 were upregulated using a cDNA GeneChip, and CD44(high)CD58(high) cancer cells, the common existence of which was demonstrated by flow cytometry in multiple colon cancer cell lines and primary specimens, exhibited enhanced self-renewal ability, epithelial-mesenchymal transition ability and tumorigenicity, both in vitro and in vivo. Furthermore, activated CD58 upregulated the Wnt/β-catenin pathway and thus promoted self-renewal of CT-ICs; conversely, knockdown of CD58 significantly impaired sphere formation and tumor growth. With immunoprecipitation and western blotting approaches, CD58 was found to upregulate the Wnt pathway by degradation of Dickkopf 3. These results indicate that CD58 is a novel cell-surface marker that functionally regulates self-renewal of CT-ICs, which may provide an intriguing therapeutic target for the efficient killing and elimination of CT-ICs.

Histone phosphorylation: its role during cell cycle and centromere identity in plants

As the main protein components of chromatin, histones can alter the structural/functional capabilities of chromatin by undergoing extensive post-translational modifications (PTMs) such as phosphorylation, methylation, acetylation, ubiquitination, sumoylation, and so on. These PTMs are thought to transmit signals from the chromatin to the cell machinery to regulate various processes. Histone phosphorylation is associated with chromosome condensation/segregation, activation of transcription, and DNA damage repair. In this review, we focus on how different histone phosphorylations mark for chromatin change during the cell cycle, the relationship between histone phosphorylation and functional centromeres, and the candidate kinases that trigger and the phosphatase or kinase inhibitors that alter histone phosphorylation. Finally, we review the crosstalk between different PTMs.

Knockdown of VEGFR2 inhibits proliferation and induces apoptosis in hemangioma-derived endothelial cells

Angiogenesis is a process of development and growth of new capillary blood vessels from pre-existing vessels. Angiogenic growth factors play important roles in the development and maintenance of some malignancies, of which vascular endothelial growth factor (VEGF)/VEGFR2 interactions are involved in proliferation, migration, and survival of many cancer cells. The aim of this study was to investigate the function of VEGFR2 in human hemangiomas (HAs). Using immunohistochemistry assay, we examined the expression levels of VEGF, VEGFR2, Ki-67, glucose transporter-1 (Glut-1), phosphorylated protein kinase B (p-AKT) and p-ERK in different phases of human HAs. Positive expression of VEGF, VEGFR2, Ki-67, Glut-1, p-AKT and p-ERK was significantly increased in proliferating phase HAs, while decreased in involuting phase HAs (P=0.001; P=0.003). In contrast, cell apoptotic indexes were decreased in proliferating phase HAs, but increased in involuting phase HAs (P&lt;0.01). Furthermore, we used small hairpin RNA (shRNA)-mediated VEGFR2 knockdown in primary HA-derived endothelial cells (HemECs) to understand  the  role  of  VEGF/VEGFR2 signaling. Knockdown of VEGFR2 by Lv-shVEGFR2 inhibited cell viability and induced apoptosis in primary HemECs companied with decreased expression of p-AKT, p-ERK, p-p38MAPK and Ki-67 and increased expression of caspase-3 (CAS-3). Overexpression of VEGFR2 promoted cell viability and blocked apoptosis in Lv-VEGFR2-transfected HemECs. Taken together, our findings demonstrate that, increased expression of VEGFR2 is involved in the development of primary HemECs possibly through regulation of the AKT and ERK pathways, suggesting that VEGFR2 may be a potential therapeutic target for HAs. 

Anti-phosphorylated histone H2AThr120: a universal microscopic marker for centromeric chromatin of mono- and holocentric plant species

Based on the analysis of 20 different monocot and eudicot species, we propose that the centromeric distribution of the phosphorylated histone H2AThr120 is evolutionary highly conserved across species with mono- and holocentric chromosomes. Therefore, antibodies recognizing the phosphorylated threonine 120 of the histone H2A can serve as a universal marker for the cytological detection of centromeres of mono- and holokinetic plant species. In addition, super resolution microscopy of signals specific to the centromere-specific histone H3 variant CENH3 and to H2AThr120ph revealed that these histone variants are incorporated into different nucleosomes, which form distinct, partly intermingled chromatin domains. This specific arrangement of both histone variants suggests different centromeric functions during the cell cycle.

Abstract P5-03-03: Effect of rapamycin on the function and transformation of aged murine mammary stem cells

Age is the number one risk fact for breast cancer with only 5% of all breast cancers occurring in women under 40 years old and age specific incidence of invasive breast cancer increases from less than 1.5% at age 40, to about 3% at age 50 and over 4% by age 70 in American women. Recent research implicated that adult mammary stem cells (MaSCs) might be responsible for the initiation and progression of certain types of breast cancer. Our preliminary study showed that aging is associated with a significant increase of MaSC frequency, but with a functional decline of self-renewal and differentiation as well as increased neoplastic transformation potential. These findings indicate that aged MaSCs might be the precursors of preneoplastic lesions and serve as the cell of origin for malignant transformation in breast tissue. Therefore, intervention of MaSC aging process could be an effective method for cancer prevention. The drug of rapamycin has been shown to extend life span and ameliorate age-related pathologies (e.g., cancer) in murine models, and a recent study suggested that rapamycin's anti-aging effect may partially act through enhancing the function of tissue-specific stem cells. It is unknown whether rapamycin treatment will also enhance the function of aged MaSCs and decrease their transformation potential. In this study, we fed C57BL/6 mice with microencapsulated rapamycin-containing food (14 mg/kg, food designed to deliver ∼2.24 mg of rapamycin per kg body weight/day to achieve about 4 ng/ml of rapamycin per kg body weight/day) or control diet with empty capsules for 2 year (starting at 2-month old) or 5-10 days (starting at 25.5-month old) and then isolated primary mammary cells at 26-month old for MaSC quantification using an in vitro mammosphere formation and 3D-ECM sphere differentiation assay as well as by the in vivo cleared mammary fat pad transplantation assay. Our findings indicate that short-term (5-10 days) or long-term (&gt; 2 year) rapamycin treatment reversed phenotypic changes associated with aged MaSC, which was mainly characterized by decreased luminal-to-basal cell ratio and increased MaSC frequency. Histological analysis of regenerated glands of aged MaSCs derived from control and rapamycin-treated mice showed a significant decrease of early neoplastic transformation potential in rapamycin-treated group. Subsequent in vivo serial transplantation and mating experiments revealed that rapamycin treatment reverted aged MaSCs more resemble to young MaSCs in self-renewal/differentiation function during regeneration and improved lobulo-alveolar differentiation function for lactation. In conclusion, our findings suggest that rapamycin can rejuvenate the function of aged MaSCs as well as reduce their incidence of preneoplastic transformation.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-03-03.

Bosentan reduces neuronal apoptosis following spinal cord ischemic reperfusion injury

STUDY DESIGN

Experimental study.

OBJECTIVES

To investigate the effects of endothelin-receptor antagonist Bosentan on the spinal neural apoptosis in rats with ischemic reperfusion (IR) injury.

SETTING

Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University School of Medcine, Xi'an, Shaanxi Province, China:

METHODS

Sprague-Dawley Rats were randomly divided into two groups, saline (IRS, n=48) and Bosentan (IRB, n=48) treatment, respectively, when reperfused in 6 h, 12 h, 24 h, 3 days, 5 days and 7 days. Immunohistochemical staining was used to assess endothelin-1 (ET-1), endothelin receptor type A (ETRA), endothelin receptor type B (ETRB), Bcl-2, Bax, Caspase-8, Caspase-9 and Caspase-3 expression. ET-1 and its receptor in spinal cord tissue were evaluated by real-time PCR. Plasma ET-1 concentration was also detected using radioimmunoassay.

RESULTS

Compared with the group IRS, plasma concentration of ET-1 in group IRB was significantly increased at each time point (P<0.05) and peaked at 24 h (P<0.01). ETRB expression in group IRB was significantly higher than group IRS at each time point (P<0.05) and peaked at day 3 (P<0.01). The difference in the expression of ETRA was not statistically significant in the group IRS and IRB (P>0.05). The apoptosis rate in group IRB was significantly decreased at each time point (P<0.05). The protein expressions of Bcl-2, Bax, Caspase-8, Caspase-9 and Caspase-3 were significantly increased in response to Bosentan treatment after IR.

CONCLUSION

These results suggest Bosentan decreases apoptosis rate after IR injury in the spinal cord, possibly through the ET-1-ETRB signaling pathway.