Multivariate analysis of the effect of Chalazia on astigmatism in children

Background

Chalazion may affect visual acuity. This study aimed to evaluate refractive status of chalazia and effect of different sites, sizes, and numbers of chalazion on astigmatism.

Methods

Three hundred ninety-eight patients aged 0.5–6 years were divided into the chalazion group (491 eyes) and the control group (305 eyes). Chalazia were classified according to the site, size, and number. Refractive status was analyzed through the comparison of incidence, type, mean value and vector analysis.

Results

The incidence, type, refractive mean and of astigmatism in the chalazion group were higher than those in the control group, and the difference was statistically significant (P < 0.05). For comparison of the incidence, the middle-upper eyelid (50%) was highest, followed by 41.77% in the medial-upper eyelid, both higher than that in the control group (P < 0.05). In medium (54.55%) and large groups (54.76%) were higher than that in the control group (27.21%) (P < 0.05). In multiple chalazia, the astigmatism incidence for chalazion with two masses was highest (56%), much higher than that in the control group (P < 0.05). However, this difference was not significant in chalazion with ≥3 masses (P > 0.05). For comparison of the refractive mean,the medial-upper eyelid, middle-upper eyelid and medial-lower eyelid were higher than the control group (P < 0.05) (P < 0.05). The 3-5 mm and >5 mm group were higher than those in the control group and <3 mm group(P < 0.05), and the>5 mm group was larger than the 3-5 mm group，suggesting that the risk of astigmatism was higher when the size of masses > 5 mm. Astigmatism vector analysis can intuitively show the differences between groups, the results are the same as refractive astigmatism.

Conclusion

Chalazia in children can easily lead to astigmatism, especially AR and OBL. Chalazia in the middle-upper eyelid, size ≥3 mm, and multiple chalazia (especially two masses) are risk factors of astigmatism. Invasive treatment should be performed promptly if conservative treatment cannot avoid further harm to the visual acuity due to astigmatism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02529-1.

Effect of the BOPPPS model combined with case-based learning versus lecture-based learning on ophthalmology education for five-year paediatric undergraduates in Southwest China

BACKGROUND

To investigate the effect of the bridge-in, objective, preassessment, participatory learning, post assessment, and summary (BOPPPS) model combined with case-based learning (CBL) on ophthalmology teaching for five-year paediatric undergraduates.

METHODS

The effects of the BOPPPS model combined with CBL (BOPPPS-CBL) and traditional lecture-based learning (LBL) on ophthalmology teaching were compared among students in a five-year programme. The questionnaire surveys of the students were collected and statistically analysed after the class. The final examination scores, including on elementary knowledge and case analysis, in the two groups were analysed.

RESULTS

There were no statistically significant differences between the teachers and students in the baseline data. More students agreed that the BOPPPS-CBL model helped develop their problem-solving skills, analytical skills and motivation for learning better than the LBL model. There was no significant difference in learning pressure between the two groups. The final examination scores of the BOPPPS-CBL group were significantly higher than those of the LBL group. The overall course satisfaction of the BOPPPS-CBL group was obviously higher than that of the LBL group.

CONCLUSIONS

The BOPPPS-CBL model is an effective ophthalmology teaching method for five-year paediatric undergraduates.

Downregulation of miR-211-5p Promotes Carboplatin Resistance in Human Retinoblastoma Y79 Cells by Affecting the GDNF-LIF Interaction

Purpose

To investigate the role of the miR-211-5p-GDNF signaling pathway in carboplatin resistance of retinoblastoma Y79 cells and what factors it may be affected by.

Methods

A carboplatin-resistant retinoblastoma cell line (Y79R) was established in vitro. RNA-seq and microRNA-seq were constructed between Y79 and Y79R cells. RNA interference, RT-PCR, Western blot (WB), and flow cytometry were used to verify the expression of genes and proteins between the two cell lines. The TargetScan database was used to predict the microRNAs that regulate the target genes. STING sites and Co-Immunoprecipitation (COIP) were used to study protein–protein interactions.

Results

GDNF was speculated to be the top changed gene in the drug resistance in Y79R cell lines. Moreover, the speculation was verified by subsequent RT-PCR and WB results. When the expression of GDNF was knocked down, the IC50 of the Y79R cell line significantly reduced. GDNF was found to be the target gene of miR-211-5p. Downregulation of miR-211-5p promotes carboplatin resistance in human retinoblastoma Y79 cells. MiR-211-5p can regulate the expression of GDNF. Our further research also found that GDNF can bind to LIF which is also a secreted protein.

Conclusion

Our results suggest that downregulation of miR-211-5p promotes carboplatin resistance in human retinoblastoma Y79 cells, and this process can be affected by GDNF–LIF interaction. These results can provide evidence for the reversal of drug resistance of RB.

Refractive status and optical components in premature infants with and without retinopathy of prematurity: A 4- to 5-year cohort study

This study was aimed to investigate the characteristics of refractive parameters in premature infants and children aged 3-8 years with mild retinopathy of prematurity (ROP) and to explore the effects of premature delivery and mild ROP on the development of refractive status and ocular optical components. Premature infants who underwent ocular fundus oculi screening in our hospital between January 2009 and February 2011 were included and divided into the ROP group and the non-ROP group. Full-term infants were the controls. The results of the annual ocular examination conducted between 2014 and 2018 were analysed, and the refractive status, optical components, and developmental trends were compared among the three groups. The total follow-up time was 4-5 years. The prevalence of myopia and astigmatism was high in the ROP group (P < 0.05). In the non-ROP group, the prevalence of myopia was also higher than that in the control group. The prevalence of myopia increased with age in the ROP and non-ROP groups, while the prevalence of astigmatism remained unchanged. In the ROP group, the corneal refractive power was the largest, the lens was the thickest and the ocular axis was the shortest; in the control group, the corneal refractive power was the smallest, the lens was the thinnest, and the ocular axis was the longest. These parameters in the non-ROP group were between those in the two groups mentioned above (P < 0.05). The corneal refractive power was relatively stable at 3-8 years old in the three groups. The change in lens thickness was small in both the ROP group and the non-ROP group (P = 0.75, P = 0.06), and the lens became thinner in the control group (P < 0.001). The length of the ocular axis increased in the three groups. Preterm infants are more likely to develop myopia than full-term infants, and children with ROP are more likely to develop both myopia and astigmatism. Thicker lenses were the main cause of the high prevalence of myopia in premature infants with or without ROP.

Influence of Vitamin A deficiency on the transcriptomic profile of rat meibomian glands

PURPOSE

Vitamin A deficiency (VAD) is associated with chalazion in young children. However, the underlying molecular mechanism remains unclear. In the present study, transcriptome data from rat meibomian glands (MGs) were analyzed to reveal specific molecular responses to VAD.

METHODS

Total RNA was extracted and purified for library preparation and transcriptome sequencing. Differentially expressed genes (DEGs) between vitamin A normal (VAN) and VAD rats were analyzed using DESeq software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed using the GO seq R package and KOBAS software. Real-time quantitative reverse transcription polymerase chain reaction was used to validate the RNA sequencing results.

RESULTS

The number of DEGs in the VAD group compared to the VAN group was 3129 (1531 upregulated and 1598 downregulated) in the rat MGs. VAD upregulated a large number of lipid metabolism-related genes. GO analysis showed that the most enriched and meaningful terms were related to lipid metabolism (e.g., "oxidation-reduction process, GO: 0,055,114," "lipid metabolic process, GO: 000,662"). KEGG pathway analysis showed that most of the enriched signaling pathways were involved in lipid metabolism, including the PPAR signaling pathway associated with retinoic acid (RA)-mediated nuclear receptors.

CONCLUSION

These findings demonstrate that VAD regulates the expression of numerous genes in the rat MG and that many of these genes are involved in lipid metabolic pathways.

Deep small RNA-Seq reveals microRNAs expression profiles in lactating mammary gland of 2 sheep breeds with different milk performance

Micro ribonucleic acid (miRNA) is a type of noncoding RNA, and it has been revealed to play important roles in the activity of the mammary gland (MG) in some species. However, the function of miRNAs in MG of sheep is poorly understood. In the study, Gansu Alpine Merino (GAM; n = 9) and Small-tailed Han sheep (STH; n = 9) with different milk production traits were investigated. Microstructures and the expression profile of miRNAs of MG tissues at peak lactation were studied. Mature alveolar lumens of MG in appearance were larger in STH than GAM. The expression levels of CSN2 and the content of rough endoplasmic reticulum were also higher in STH ewes than GAM ewes. A total of 124 mature miRNAs were expressed, and 18 of these were differentially expressed between the 2 breeds. The KEGG analysis results showed that the targeted genes of differentially expressed miRNAs were mainly involved in some metabolic pathways and signaling pathways related to MG development, milk protein, and fat synthesis. The findings in the study can improve our understanding of the roles of miRNAs in the development and lactation of MG in sheep.

Solution Processed Hybrid Polymer: HgTe Quantum Dot Phototransistor with High Sensitivity and Fast Infrared Response up to 2400 nm at Room Temperature

Narrow bandgap semiconductor-based photodetectors often suffer from high room-temperature noise and are therefore operated at low temperatures. Here, a hybrid poly(3-hexylthiophene) (P3HT): HgTe quantum dot (QD) phototransistor is reported, which exhibits high sensitivity and fast photodetection up to 2400 nm wavelength range at room temperature. The active layer of the phototransistor consists of HgTe QDs well dispersed in a P3HT matrix. Fourier-transform infrared spectra confirm that chemical grafting between P3HT and HgTe QDs is realized after undergoing prolonged coblend stirring and a ligand exchange process. Thanks to the shifting of the charge transport into the P3HT and the partial passivation of the surface traps of HgTe QDs in the blend, the P3HT: HgTe QD hybrid phototransistor shows significantly improved gate-voltage tuning, 15 times faster response, and ≈80% reduction in the noise level compared to a pristine HgTe QD control device. More than 1011 Jones specific detectivity (estimated from the noise spectral density measured at 1 kHz) is achieved at room temperature, and the response time (measured at 22 mW cm-2 illumination intensity) of the device is less than 1.5 µs. That is comparable to commercial epitaxially grown IR photodetectors operated in the same wavelength range.

Refractive status and optical components of premature babies with or without retinopathy of prematurity at 7 years old

BACKGROUND

This study aimed to investigate the refractive status and optical components of premature babies with or without retinopathy of prematurity (ROP) at 7 years old and to explore the influence of prematurity and ROP on the refractive status and optical components.

METHODS

From January 2009 to February 2011, premature babies receiving fundus photographic screening (FPS) were recruited and divided into non-ROP group and ROP group. Full-term babies matched in age were recruited as controls. Auto-refractometer was employed to detect the corneal refractive power, corneal radius (CR) of curvature and corneal astigmatism, A-scan ultrasonography was performed to detect the anterior chamber depth (ACD), lens thickness (LT), vitreous thickness (VITR) and ocular axial length (AL), and retinoscopy was done following cycloplegia with 1% cyclopentolate in these babies at 7 years old. These parameters were compared among groups, and the correlations of gestational age and birth weight with the refractive status and optical components were further evaluated.

RESULTS

Of 126 subjects, a total of 252 eyes were evaluated in this study, including 50 eyes of 25 subjects in ROP group (pre-threshold stage 1-3), 110 eyes of 55 subjects in non-ROP group and 92 eyes of 46 subjects in control group. The incidence of myopia was the highest in ROP group (9/50, 18%), followed by non-ROP group (11/110; 10%) and control group (6/92; 6.52%). The incidence of hyperopia was the highest in control group (21/92; 22.83%), followed by ROP group (8/50; 16%) and non-ROP group (10/110; 9.09%). The incidence of astigmatism was the highest in ROP group (18/50; 36%), followed by non-ROP group (25/110; 22.73%) and control group (12/92; 13.04%). The corneal astigmatism (-1.58, -1.11, -0.86 DC, P<0.01) and the mean degree of astigmatism (1.38, 1.17, 0.64 DC, P<0.05) in ROP group and non-ROP group were significantly higher than those in control group. The corneal refractive power in ROP group was more potent as compared to non-ROP group and control group (43.98, 43.16, 42.99 D, P<0.05); the corneal curvature in ROP group was significantly higher than that in non-ROP group and control group (7.87, 7.71, 7.67 mm, P<0.05); the ocular AL in ROP group and non-ROP group was significantly shorter than that in control group (2.41, 22.47, 22.78 mm, P<0.05). The LT in ROP group and non-ROP group was markedly thicker than that in control group (4.48, 4.45, 4.37 mm, P>0.05); the ACD in ROP group and non-ROP group was markedly deeper than in control group (3.16, 3.12, 3.21 mm, P>0.05). The gestational age was negatively related to corneal astigmatism (r=-0.208, P=0.013) and astigmatism (r=-0.226, P=0.004), but positively associated with ocular AL (r=0.252, P=0.005). The birth weight was negatively associated with corneal astigmatism (r=-0.30, P<0.001), astigmatism (r=-0.267, P=0.001), corneal refractive power (r=-0.255, P=0.001) and corneal curvature (r=0.242, P=0.001), but positively to ocular AL (r=0.243, P=0.001) and spherical equivalent refraction (SER) (r=0.151, P=0.028).

CONCLUSIONS

(I) Premature babies with or without ROP are susceptible to myopia and astigmatism; (II) low birth weight, prematurity and ROP synergistically influence the development of refractive status and optical components, resulting in myopia and astigmatism; (III) premature babies with or without ROP have increased corneal curvature and LT, which are related to the higher incidence of myopia and astigmatism.

Tailoring spontaneous infrared emission of HgTe quantum dots with laser-printed plasmonic arrays

Chemically synthesized near-infrared to mid-infrared (IR) colloidal quantum dots (QDs) offer a promising platform for the realization of devices including emitters, detectors, security, and sensor systems. However, at longer wavelengths, the quantum yield of such QDs decreases as the radiative emission rate drops following Fermi's golden rule, while non-radiative recombination channels compete with light emission. Control over the radiative and non-radiative channels of the IR-emitting QDs is crucially important to improve the performance of IR-range devices. Here, we demonstrate strong enhancement of the spontaneous emission rate of near- to mid-IR HgTe QDs coupled to periodically arranged plasmonic nanoantennas, in the form of nanobumps, produced on the surface of glass-supported Au films via ablation-free direct femtosecond laser printing. The enhancement is achieved by simultaneous radiative coupling of the emission that spectrally matches the first-order lattice resonance of the arrays, as well as more efficient photoluminescence excitation provided by coupling of the pump radiation to the local surface plasmon resonances of the isolated nanoantennas. Moreover, coupling of the HgTe QDs to the lattice plasmons reduces the influence of non-radiative decay losses mediated by the formation of polarons formed between QD surface-trapped carriers and the IR absorption bands of dodecanethiol used as a ligand on the QDs, allowing us to improve the shape of the emission spectrum through a reduction in the spectral dip related to this ligand coupling. Considering the ease of the chemical synthesis and processing of the HgTe QDs combined with the scalability of the direct laser fabrication of nanoantennas with tailored plasmonic responses, our results provide an important step towards the design of IR-range devices for various applications.

Association between allergic conjunctivitis and provisional tic disorder in children

BACKGROUND

Allergic diseases are associated with a higher risk of Tourette's syndrome (TS). Provisional tic disorder (PTD) and eye blinking are often reported as the initial symptoms both in TS and in allergic conjunctivitis (AC).

OBJECTIVE

To investigate the association between AC and PTD in children of 4-10 years of age in southwest China.

METHODS

This case-control study was carried out at the Children's Hospital of Chongqing Medical University between January 2016 and June 2017. Age- and gender-matched children without PTD were included as the control group. Intraocular pressure was measured by non-contact tonometry, tear film break-up time by slit-lamp examination, and allergens by skin prick test (SPT). Multivariable logistic regression analysis was applied to adjust for the simultaneous effects of AC, dry eye, and allergic history in children with PTD.

RESULTS

The frequency of AC was higher in the PTD group (74.3%, 52/70) than in the control group (17.1%, 12/70) (P < 0.001). The frequencies of positive SPT were found to be higher in the PTD group (80.0%, 56/70) than in the control group (20.0%, 14/70). AC, dry eye, and history of allergic rhinitis were significantly associated with PTD.

CONCLUSION

The frequencies of AC are high in children with PTD. AC and dry eye may be both associated with PTD in children.

The antitumor function of arctigenin in human retinoblastoma cells is mediated by jagged‑1

Retinoblastoma is an intraocular malignant tumor that may severely affect vision and represents a life‑threatening disease in children. Arctigenin (ATG) is an active compound that exhibits numerous pharmacological activities, which is isolated from the seeds of greater burdock (Arctium lappa Linnaeus), a plant used in traditional Chinese herbal medicine. The present study aimed to investigate the effects of ATG on cancer progression by analyzing the retinoblastoma cell line Y79. ATG exhibited a significant inhibitory effect on the viability of Y79 cells in a dose‑dependent manner. Furthermore, treatment with ATG promoted apoptosis, and increased the protein expression levels of B‑cell lymphoma 2 (BCL‑2)‑associated X protein and decreased the protein expression levels of BCL‑2. Cell migration was suppressed following treatment with ATG, as assessed by Transwell migration assay. Furthermore, the protein expression levels of jagged‑1 (JAG1) were decreased, and various factors involved in the Notch signaling pathway, including the Notch intracellular domain (NICD), transcription factor HES (HES)5 and HES1 were downregulated following treatment with ATG. The decreased expression levels of JAG1 were restored in response to JAG1 overexpression, alongside increases in the protein expression levels of NICD, HES5 and HES1. Furthermore, overexpression of JAG1 partly restored the cell viability and migration suppressed following treatment with ATG. In addition, ATG‑induced apoptosis was reduced by JAG1 overexpression. Collectively, the present results suggested that ATG may serve as an antitumor compound by suppressing the proliferation and migration of retinoblastoma cells, inducing apoptosis, downregulating the protein expression levels of JAG1, and decreasing the activity of the Notch signaling pathway.

The protective efficacy and safety of bandage contact lenses in children aged 5 to 11 after frontalis muscle flap suspension for congenital blepharoptosis: A single-center randomized controlled trial

BACKGROUND

Postoperative complications, lagophthalmos and exposure keratopathy sometimes occur after surgery for congenital blepharoptosis. Bandage contact lenses (BCL) can help prevent some ocular surface disorders. The study aims to evaluate the efficacy and safety of BCL for protection of the ocular surface in children aged 5 to 11 years after frontalis muscle flap suspension for congenital blepharoptosis.

METHODS

We conducted a prospective randomized clinical study of 30 eyes of 30 patients with congenital blepharoptosis consecutively enrolled at the Ophthalmology Ward of the Children's Hospital of Chongqing Medical University, China from September 1, 2016, to February 30, 2017. After frontalis muscle flap suspension surgery, patients were randomly assigned to undergo BCL application (BCL group, 15 eyes) or no BCL application (control group, 15 eyes). All patients were treated with bramycin 0.3% and polyvinyl alcohol drops after surgery. The primary outcomes were dry eye assessed by tear film break time (TFBUT), fluoresce in corneal staining (FCS) on slit-lamp on days 1, 3, and 15 postoperatively, and lower tear meniscus height (LTMH) on optical coherence tomography on days 1 and 15 postoperatively. Secondary outcomes were pairwise correlation of TFBUT, FCS and LTMH.

RESULTS

In the BCL group, abnormal TFBUT and FCS were only found in 2 patients (13.33%) on postoperative day 15. In the control group, the incidence of dry eye assessed by TFBUT was 67.00% (10/15 eyes) on day 1, 73.33% (11/15 eyes) on day 3, and 53.33% (8/15 eyes) on day 15 (P < .001). LTMH were significantly higher in the BCL group than the control group postoperatively (P < .001). Significant positive correlations were found between LTMH and TFBUT pre-operation and on days 1 and 15 post-operation. For LTMH and FCSS (R = -0.815, P < .001), and TFBUT and FCS (R = -0.837, P < .001), the Pearson coefficient was negative on postoperative day 1, but not correlated on day 15.

CONCLUSIONS

Silicone hydrogel BCL were safe and efficacious for protective use in children after frontalis muscle flap suspension for congenital blepharoptosis.

Methods for Structural and Functional Analyses of Intramembrane Prenyltransferases in the UbiA Superfamily

The UbiA superfamily is a group of intramembrane prenyltransferases that generate lipophilic compounds essential in biological membranes. These compounds, which include various quinones, hemes, chlorophylls, and vitamin E, participate in electron transport and function as antioxidants, as well as acting as structural lipids of microbial cell walls and membranes. Prenyltransferases producing these compounds are involved in important physiological processes and human diseases. These UbiA superfamily members differ significantly in their enzymatic activities and substrate selectivities. This chapter describes examples of methods that can be used to group these intramembrane enzymes, analyze their activity, and screen and crystallize homolog proteins for structure determination. Recent structures of two archaeal homologs are compared with structures of soluble prenyltransferases to show distinct mechanisms used by the UbiA superfamily to control enzymatic activity in membranes.

High incidence of dry eye in young children with allergic conjunctivitis in Southwest China

PURPOSE

To identify the prevalence of dry eye in pediatric population with allergic conjunctivitis in Southwest China.

METHODS

A single-centre, prospective, case-control study conducted between May 2015 and December 2015 included 40 children, 3-6 years of age, with seasonal allergic conjunctivitis (SAC) or perennial allergic conjunctivitis (PAC) and 40 age- and gender-matched children undergoing medical healthy examination without history of allergy or dry eye as a control. A dry eye score system (DESS) was administered to both groups. Slit-lamp examinations including tear film break-up time (TFBUT) and fluorescent corneal staining (FCS) were performed. Correlation analyses were performed to evaluate associations between measures of dry eye and signs and symptoms of AC.

RESULTS

The prevalence of dry eye was 97.5% (78/80 eyes) in cases and 27.50% (22/80 eyes) in controls. Mean DESS score was 4.75 ± 2.22 in the case group and 0.80 ± 1.22 in the control group (p < 0.001). Symptoms of dry eye in the case group were mild (<6). Mean tear film break-up time was 6.54 ± 1.48 seconds in the case group and 10.04 ± 1.79 seconds in the control group (p < 0.001). Mean FCS scores were 0.79 ± 1.34 and 0.21 ± 0.57, respectively (p = 0.001). The DESS score and TFBUT were both associated with the duration of allergic conjunctivitis.

CONCLUSION

The incidence of dry eye assessed by TFBUT was higher in young children with SAC and PAC than in controls. However, subjective symptoms of dry eye (DESS) were inconsistent with objective signs, indicating that close attention should be paid to the evaluation and treatment of dry eye in pediatric population with AC.

Refractive status and optical components of premature babies with or without retinopathy of prematurity at 3-4 years old

PURPOSE

To investigate the refractive status and optical components of premature babies with or without retinopathy of prematurity (ROP) at 3-4 years old, and to explore the influence of prematurity and ROP on the refractive status and optical components.

METHODS

Premature babies receiving fundus examination were recruited into ROP group and non-ROP group, with age-matched full-term babies as controls.

RESULTS

The incidence of myopia was the highest in ROP (3/59, 5.08%). The incidence of astigmatism was significantly different between ROP (37.29%, 22/59) and controls (17.86%, 15/84). The corneal refractive power in ROP and non-ROP was more potent compared with controls (P<0.05); corneal curvature was steeper (P<0.05); lens thickness was thinner (P<0.05); ocular axial length was shorter P<0.05). The gestational age was negatively related to corneal astigmatism and astigmatism, positively associated with vitreous thickness and axial length. The birth-weight was negatively associated with corneal astigmatism, astigmatism and corneal refractive power, positively related to corneal radius of curvature, vitreous thickness and ocular axial length.

CONCLUSION

Premature babies with or without ROP are susceptible to myopia and astigmatism. ROP, prematurity and low birth-weight synergistically influence the development of refractive status and optical components, of which the prematurity and low birth-weight are more important.

Multidimensional GPCR profiling and screening using impedance-based label-free and real-time assay

GPCRs constitute one of the most sought-after targets in drug discovery because they are associated with conditions ranging from cardiovascular diseases, autoimmune diseases, inflammation, cancer, and diseases of the nervous system. Moreover, they are one of the most amenable targets for drug discovery because they can be modulated by small molecules, peptides, proteins, and antibodies. Therefore it may not come as a surprise that close to 40 % of the drugs that are currently on the market are targeting GPCRs. It has become evident that GPCR signaling is highly complex and may involve multiple or a subset of pathways depending on the interaction of a GPCR with an agonist or antagonist. It is imperative that any functional screening for GPCR activity integrates this complexity. In this assay protocol, we describe how the xCELLigence RTCA HT impedance-based platform which can be used for functional cell-based GPCR assays can be utilized for GPCR screening.

Incidence of retinopathy of prematurity in southwestern China and analysis of risk factors

Background

The aim of this study was to screen for retinopathy of prematurity (ROP) in southwestern China and understand the prevalence and risk factors of ROP, which may provide evidence useful in the prevention and treatment of ROP.

Material/Methods

1864 preterm infants (gestational age of <37 weeks and birth weight of ≤2500 g) underwent ROP screening from January 2009 to November 2012 in Southwest China. The medical information of infants during perinatal period was reviewed, and risk factors of ROP were determined. A total of 1614 infants were recruited for final analysis.

Results

Incidence of ROP was 12.8%. The first, second, third, and fourth stage of ROP was found in 64.6%, 29.6%, 3.4%, and 0.5% of infants, respectively. No fifth stage of ROP was observed. In addition, 7.7% of infants required surgical intervention. In our Department of Neonatology, the incidence of ROP was 20.0%, which was significantly higher than in non-hospitalized patients (9.9%). The incidence of ROP remained unchanged over the years. Independent risk factors of ROP included low birth weight (p=0.049), low gestational age (p=0.008), days of oxygen supplementation (p=0.008), and myocardial injury after birth (p=0.001).

Conclusions

The prevalence of ROP in preterm infants is relatively high in Southwest China, and low birth weight, low gestational age, days of oxygen supplementation, and myocardial injury after birth are independent risk factors for ROP.

Prevalence of low serum vitamin a levels in young children with chalazia in southwest china

PURPOSE

To detect risk factors that may be related to chalazia in children in southwest China.

DESIGN

Prospective case-control study.

METHODS

The case group, 88 children with chalazia, was divided into 2 subgroups. One had 48 children 6 months to 6 years of age (defined as young children), and the other had 40 children 7 to 12 years of age (defined as older children). The control group consisted of 40 young children and 32 older children. Clinical findings for patients were recorded. Serum was tested for concentrations of vitamin A, vitamin D3, and immunoglobulin E.

RESULTS

World Health Organization definitions were used for vitamin A deficiency (< 0.7 μmol/L) and marginal vitamin A deficiency (0.7 to 1.05 μmol/L). The average level of serum vitamin A in the case group was significantly lower than that in the control group (P < .001). Analyses failed to find significant differences in vitamin D3 or immunoglobulin E levels between the case and control groups. The average vitamin A level in young children with multiple chalazia (0.65 ± 0.12 μmol/L) was low. Blepharitis was less prevalent than low serum vitamin A levels in the young child subgroup (odds ratios, 8.5 and 96.9, respectively), but higher than in older children (odds ratios, 17.5 and 9.0, respectively).

CONCLUSIONS

Low serum vitamin A is associated with a chalazion in young children in southwest China, especially young children with multiple chalazia.

Prevalence of eye diseases and causes of visual impairment in school-aged children in Western China

Background

The present study investigated the prevalence of refractive error, visual impairment, and eye diseases in school-aged children in western China.

Methods

The survey was done in a representative county (Yongchuan District, Chongqing Municipality) of western China. Cluster random sampling was used to select children aged 6 to 15 years. We conducted door-to-door surveys and eye examinations including optometry, stereoscopic vision test, eye position and eye movement, slit lamp examination of the anterior segment, retinoscopy, and fundus examination after cycloplegia with 1% cyclopentolate.

Results

Among 3469 children, data were available for 3079 (88.76%). The prevalences of eye diseases were, in descending order, refractive error (20.69%; 637/3079), conjunctivitis (11.76%; 362/3079), amblyopia (1.88%; 58/3079), color vision defect (0.52%; 16/3079), keratitis (0.36%; 11/3079), strabismus (0.29%; 9/3079), cataract (0.23%; 7/3079), pathologic myopia (0.19%; 6/3079), and ocular trauma (0.13%; 4/3079). The prevalence of corneal leucoma, corneal staphyloma, optic neuropathy, macular degeneration, and myelinated nerve fibers was 0.03% (1/3079) for each. The prevalence of visual impairment was 7.70% (237/3079), and the major causes of visual impairment were uncorrected refractive error (86.08%; 204/237), amblyopia (9.70%; 23/237), pathologic myopia (1.27%; 3/237), congenital cataract (0.42%; 1/237), and others (2.11%; 5/237).

Conclusions

Among school-aged children in a less developed area of western China, refractive error was the most prevalent eye disorder, and uncorrected refractive error was the main cause of visual impairment.

Abstract 2312: Using multidimensional real-time cell profiling approach to identify novel inhibitors of key targets and pathways involved in cancer maintenance and progression

A high throughput cell-based phenotypic screening method was developed using real time cell analysis system which is based on impedance sensor technology. Using compounds with known mechanisms, we had previously demonstrated small molecule compounds produce characteristic time-dependent cell response profiles (TCRP) which could be indicative of mechanism of action. The cellular-basis for the anti-mitotic TCRP has been extensively validated using both anti-mitotic compounds and siRNAs targeting mitotic machineries (e.g. Eg5, PLK1 & Mad2). In this study, we used the TCRP approach to screen a 119,595 compound library for novel anti-cancer agents. The screening was performed at a final concentration of 17.8 µM using a human non small cell lung cancer line, H1993. The TCRP was monitored for 48 hours after compound treatment and the data generated was analyzed using in-house developed software to perform clustering analysis. For each screening set, a panel of compounds with known mechanisms of action were used as positive control and also served as reference for TCRP-based clustering to predict mechanisms of action. After multi-dose confirmation, 239 hits with IC50 values less than 8.9 µM were subjected to TCRP analysis. In comparison with reference TCRP patterns, we indentified 26 hits corresponding to tyrosine kinase inhibitors, 9 hits as DNA damaging agents, 125 hits as anti-mitotic agents, and 28 hits as cytostatic agents. Detailed characterization of 117 putative anti-mitotic compounds with traditional p-H3 based methods demonstrates 113 of them (96.6%) mediated mitotic arrest, thus demonstrating the robust predictive nature of the approach. We also have validated the putative tyrosine kinase inhibitors in in vitro kinase assays. TCRP-based phenotypic screening displays a novel drug screening approach with great potentials for discovering new pathway-modulating anticancer agents.

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 2312. doi:10.1158/1538-7445.AM2011-2312

[Amniotic membrane transplant using fibrin glue for the treatment of deep layer corneal damage]

OBJECTIVE

To treat deep layer corneal damage using fibrin glue and amniotic membrane transplant.

METHODS

Forty-five rabbits were given deep lamellar keratectomies to cause deep layer corneal damage in their right eyes and were then randomly divided into 3 groups. The first group was given double-layer amniotic membrane transplants where fibrin glue was used to connect the two layers of amniotic membrane. The second group was given double-layer amniotic membrane transplants where no fibrin glue was used. The third group was given no treatment. Clinical outcome was graded by corneal integrity, opacity and neovascularization, and detachment of amniotic membrane was recorded. The expression of apoptosis was monitored to assess the changes of morphology and histology on the 7th, 14th and 28th days after surgery.

RESULTS

While the double-layer amniotic membrane without fibrin glue covered the cornea for (13.15 ± 2.68) d, the double-layer amniotic membrane using fibrin glue covered the surface of the cornea for (20.00 ± 2.43) d (t = 8.470, P = 0.000). The corneas in the first group recovered smoothly and transparently, maintained normal thickness and less neovascularization, whereas the corneas in the other two groups recovered irregularly, lost their transparency, became turbid and showed higher levels of neovascularization. There were statistically significant differences between the first and third groups for corneal opacity and neovascularization, where the 14th day after surgery, the first group scored 2.62 and the third group scored 5.19 (t = 3.986, P = 0.004), and the 28th day after surgery, the first group scored 2.87 and the third group scored 4.78 (t = 3.608, P = 0.007). Perforation did not appear in the first group, but the second group had 3 cases and the third group had 2 cases, all due to infection. The changes of morphology and histology showed that the damaged corneas were contained normal epithelial cells and regularly arranged fibrous cells on the 28th day after surgery. The apoptosis in corneas of the first group was less than that of the third group at all observed points (7th day: t = 8.153, P = 0.000; 14th day: t = 9.693, P = 0.000; 28th day: t = 14.050, P = 0.000), however, apoptosis in corneas in the second group was only different from that in the third group on the 7th day after surgery while other observed points showed no difference (7th day: t = 5.474, P = 0.000).

CONCLUSION

Using bio-engineered fibrin glue in amniotic membrane transplants can repair deep layer corneal damage, reduce neovascularization, scarring and corneal apoptosis.

Rapid and quantitative assessment of cell quality, identity, and functionality for cell-based assays using real-time cellular analysis

Strict quality control of cells is required for the standardization and interpretation of results in all areas of cell-based research, especially in drug discovery. Real-time cellular analysis using electrical impedance as a readout offers a rapid and highly reproducible method for quality control as it provides a quantitative measure of overall cell morphology and growth. In a case study, the authors demonstrate that samples of a single cell line obtained from several different labs show clear differences in their impedance profiles when compared with the corresponding standard cell line. A number of kinetic parameters were derived from the impedance profiles and used to quantify the differences among these cell lines. Our findings indicate that this methodology can detect cell line differences including mix-ups or contaminations, genetic alterations, and potential epigenetic changes occurring during passaging, all of which can occur in the time scale of a screening campaign. Finally, we provide evidence that these impedance profile differences can be predictive of different outcomes in cell-based functional assays for the effects of small molecules on otherwise seemingly identical cell lines.

The xCELLigence system for real-time and label-free monitoring of cell viability

We describe here the use of the xCELLigence system for label-free and real-time monitoring of cell -viability. The xCELLigence system uses specially designed microtiter plates containing interdigitated gold microelectrodes to noninvasively monitor the viability of cultured cells using electrical impedance as the readout. The continuous monitoring of cell viability by the xCELLigence system makes it possible to distinguish between different perturbations of cell viability, such as senescence, cell toxicity (cell death), and reduced proliferation (cell cycle arrest). In addition, the time resolution of the xCELLigence system allows for the determination of optimal time points to perform standard cell viability assays as well as other end-point assays to understand the mode of action. We have used the WST-1 assay (end-point viability readout), the cell index determination (continuous monitoring of viability by xCELLigence), and the DNA fragmentation assay (end-point apoptosis assay) to systematically examine cytotoxic effects triggered by two cytotoxic compounds with different cell-killing kinetics. Good correlation was observed for viability readouts between WST-1 and cell index. The significance of time resolution by xCELLigence readout is exemplified by its ability to pinpoint the optimal time points for conducting end point viability and apoptosis assays.

Screening and identification of small molecule compounds perturbing mitosis using time-dependent cellular response profiles

Cellular processes such as cell cycle progression, mitosis, apoptosis, and cell migration are characterized by well-defined events that are modulated as a function of time. Measuring these events in the context of time and its perturbation by small molecule compounds and RNAi can provide mechanistic information about cellular pathways being affected. We have used impedance-based time-dependent cell response profiling (TCRP) to measure and characterize cellular responses to antimitotic compounds or siRNAs. Our findings indicate that small molecule perturbation of mitosis leads to unique TCRP. We have further used this unique TCRP signature to screen 119 595 compound library and identified novel antimitotic compounds based on clustering analysis of the TCRPs. Importantly, 113 of the 117 hit compounds in the TCRP antimitotic cluster were confirmed as antimitotic based on independent assays, thus establishing the robust predictive nature of this profiling approach. In addition, potent and novel agents that induce mitotic arrest either by directly interfering with tubulin polymerization or by other mechanisms were identified. The TCRP approach allows for a practical and unbiased phenotypic profiling and screening tool for small molecule and RNAi perturbation of specific cellular pathways and time resolution of the TCRP approach can serve as a complement for other existing multidimensional profiling approaches.

Refractive status and prevalence of refractive errors in suburban school-age children

OBJECTIVE

This study investigated the distribution pattern of refractive status and prevalence of refractive errors in school-age children in Western China to determine the possible environmental factors.

METHODS

A random sampling strategy in geographically defined clusters was used to identify children aged 6-15 years in Yongchuan, a socio-economically representative area in Western China. We carried out a door-to-door survey and actual eye examinations, including visual acuity measurements, stereopsis examination, anterior segment and eyeball movements, fundus examinations, and cycloplegic retinoscopy with 1% cyclopentolate.

RESULTS

A total of 3469 children living in 2552 households were selected, and 3070 were examined. The distributions of refractive status were positively-skewed for 6-8-year-olds, and negatively-skewed for 9-12 and 13-15-year-olds. The prevalence of hyperopia (≥+2.00 D spherical equivalent [SE]), myopia (≤-0.50 D SE), and astigmatism (≥1.00 diopter of cylinder [DC]) were 3.26%, 13.75%, and 3.75%, respectively. As children's ages increased, the prevalence rate of hyperopia decreased (P<0.001) and that of myopia increased significantly (P<0.001). Children in academically challenging schools had a higher risk of myopia (P<0.001) and astigmatism (≥1.00DC, P =0.04) than those in regular schools.

CONCLUSION

The distribution of refractive status changes gradually from positively-skewed to negatively-skewed distributions as age increases, with 9-year-old being the critical age for the changes. Environmental factors and study intensity influence the occurrence and development of myopia.

Abstract 1192: Impedance based kinetic cellular response profiling in drug discovery and development

A novel cell-based kinetic profiling approach using impedance readout for monitoring the effect of small molecule compounds will be described. This non-invasive readout allows continuous sampling of cellular responses to biologically active compounds and the ensuing kinetic profile provides information regarding the temporal interaction of compounds with cells. The utility of this approach was tested in two approaches. First, compounds with similar mechanism of action produced similar impedance-based time-dependent cell response profiles (TCRP). The TCRP was used to identify novel mechanisms for existing drugs and also identified potential off-target activity for COX-2 inhibitor, celecoxib and the experimental compound, monastrol. The second approach entailed using this profiling approach to screen a 120,000 compound library. We identified novel anti-mitotic compounds as well as compounds interfering with DNA synthesis. Furthermore, we also identified compounds specific for oncogene addiction pathways. We will present data in support of both approaches in this presentation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1192.

Toxicity and intraocular properties of a novel long-acting anti-proliferative and anti-angiogenic compound IMS2186

PURPOSE

To investigate the intraocular properties and toxicity of IMS2186, a small molecule developed as an anti-choroidal neovascularization (anti-CNV) drug.

MATERIALS AND METHODS

Cellular toxicity and mechanism of action was tested on cell lines in vitro. Intraocular studies used rabbits for drug dissolution as well as toxicity and rats for the treatment study as well as the toxicity confirmation study. Rabbits' eyes were injected with 2.5 mg of IMS2186 and observed for 36 weeks. Laser-induced CNV in rats was treated with IMS2186, Kenalog, or phosphate-buffered saline (pBS). Fluorescein angiography (FA) and immunohistochemical processing of the globes was performed.

RESULTS

The anti-proliferative IC(50) of IMS2186 for human fibroblast cells was 1.0-3.0 microM and 0.3-3.0 microM for human cancer cells; the IC(50) of IMS2186 to inhibit endothelial tube formation was 0.1-0.3 microM. The IC(50) of IMS2186 for inhibiting the production of pro-inflammatory cytokines was 0.3-1 microM. The IC(50) of IMS2186 for inhibiting macrophage migration was 1 micrM. These biological properties were not species specific. IMS2186 can be formulated as a suspension for long-lasting release and when delivered intraocularly, no intraocular toxicity was observed by slit lamp exam, fundus exam, intraocular pressure measurements, or by electroretinography. FA showed a reduction in the leakage in eyes treated with IMS2186 and triamcinolone acetonide; DAPI staining also showed significantly less cellularity in IMS2186-treated lesions as compared to PBS (p = 0.0025).

CONCLUSION

IMS2186 may be a safe intraocular therapeutic agent for intraocular proliferation and angiogenesis.

Detection and quantitation of radiolabeled proteins in gels and blots

Permanent records of the results of electrophoretic separations of radiolabeled proteins and membrane-bound proteins (and RNA and DNA) can be made using autoradiography, fluorography, and phosphor imaging. These images can subsequently be quantified using densitometry to obtain a relative measure of the amount of radioactivity in a sample. This unit also includes descriptions of image-enhancement techniques and guidelines for selection of appropriate recording media.

Biochemical characterization of genetic mutations of GPR56 in patients with bilateral frontoparietal polymicrogyria (BFPP)

Bilateral frontoparietal polymicrogyria (BFPP) is a rare genetic disease characterized by cortical malformation associated with GPR56 mutations of frameshift, splicing, and point mutations (Science 303:2033). All the missense point mutations are located in the regions predicted to be exposed at the cell surface, e.g. the N-terminal extracellular domain (ECD), the proteolytic site (GPS), and the extracellular loops of transmembrane domain (TM), implying functionally important interaction among these domains. Wild type GPR56 protein is cleaved at the GPCR protein cleavage site (GPS) and gives rise to two subunits (ECD and TM), which are transported to cell surface. We have shown that GPR56 GPS mutant protein is defective in cleavage and surface localization, while non-GPS mutant proteins are cleaved normally but still defective in surface localization. Furthermore, all the mutant proteins demonstrated different glycosylation pattern from that of wild-type protein. PNGase F and Endo H sensitivity assays suggests that the mutant proteins are trapped in endoplasmic reticulum (ER), preventing them from trafficking to Golgi where further glycosylation modification usually occurs before destination to cell surface. Therefore, the loss-of-function of all these missense mutations is primarily caused by their failure to localize to cell surface.

Orphan G protein-coupled receptor GPR56 plays a role in cell transformation and tumorigenesis involving the cell adhesion pathway

GPR56 is an orphan G protein - coupled receptor, mutations of which have recently been associated with bilateral frontoparietal polymicrogyria, a rare neurologic disease that has implications in brain development. However, no phenotype beyond central nervous system has yet been described for the GPR56-null mutations despite abundant GPR56 expression in many non - central nervous system adult tissues. In the present study, we show that higher GPR56 expression is correlated with the cellular transformation phenotypes of several cancer tissues compared with their normal counterparts, implying a potential oncogenic function. RNA interference-mediated GPR56 silencing results in apoptosis induction and reduced anchorage-independent growth of cancer cells via increased anoikis, whereas cDNA overexpression resulted in increased foci formation in mouse fibroblast NIH3T3 cell line. When GPR56 silencing was induced in vivo in several xenograft tumor models, significant tumor responses (including regression) were observed, suggesting the potential of targeting GPR56 in the development of tumor therapies. The expression profiling of GPR56-silenced A2058 melanoma cell line revealed several genes whose expression was affected by GPR56 silencing, particularly those in the integrin-mediated signaling and cell adhesion pathways. The potential role of GPR56 in cancer cell adhesion was further confirmed by the observation that GPR56 silencing also reduced cell adhesion to the extracellular matrix, which is consistent with the observed increase in anoikis and reduction in anchorage-independent growth phenotypes. The oncogenic potential and apparent absence of physiologic defects in adult human tissues lacking GPR56, as well as the targetable nature of G protein - coupled receptor by small molecule or antibody, make GPR56 an attractive drug target for the development of cancer therapies.

A more efficient RNAi inducible system for tight regulation of gene expression in mammalian cells and xenograft animals

Two types of tetracycline-controlled inducible RNAi expression systems have been developed that generally utilize multiple tetracycline operators (TetOs) or repressor fusion proteins to overcome the siRNA leakiness. Here, we report a novel system that overexpresses the tetracycline repressor (TetR) via a bicistronic construct to control siRNA expression. The high level of TetR expression ensures that the inducible promoter is tightly bound, with minimal basal transcription, allowing for regulation solely dependent on TetR rather than a TetR fusion protein via a more complicated mechanism. At the same time, this system contains only a single TetO, thus minimizing the promoter impairment occurring in existing systems due to the incorporation of multiple TetOs, and maximizing the siRNA expression upon induction. In addition, this system combines all the components required for regulation of siRNA expression into a single lentiviral vector, so that stable cell lines can be generated by a single transduction and selection, with significant reduction in time and cost. Taken together, this all-in-one lentiviral vector with the feature of TetR overexpression provides a unique and more efficient tool for conditional gene knockdown that has wide applications. We have demonstrated the high degree of robustness and versatility of this system as applied to several mammalian cells and xenograft animals.

Ribozyme technology for cancer gene target identification and validation

Ribozymes are naturally occurring RNAs with catalytic activities including cis- or trans- cleavage of RNA at predefined sequence sites. This activity has been exploited for specific gene inactivation in cells during the last two decades, and ribozymes have been important functional genomics tools, especially in the pre-RNAi era. It has also been broadly applied in drug target identification and validation in pharmaceutical R&D. This chapter covers many application principles and case studies of ribozyme technology in the areas of cancer research. We also described RNAi applications in some of the same studies for comparison. Although RNAi may be more effective than ribozymes in many respects, they are nonetheless built on many of the same principles.

A new inducible RNAi xenograft model for assessing the staged tumor response to mTOR silencing

Human xenograft tumor models are widely used for efficacy evaluation of potential cancer targets. siRNA is usually stably introduced into tumor cells prior to transplantation. However, silencing of the cancer therapeutic target usually results in reduced cell growth/survival in vitro and/or failure to establish tumors in vivo, thus hindering tumor response-based efficacy evaluation. The present study explored a new tumor response model based on regulated RNAi, which is more relevant from a clinical standpoint. As a proof of principle, an inducible lentiviral RNAi vector was used to silence the known cancer therapeutic target mTOR upon induction with Doxycycline (DOX). The responses to DOX-induced mTOR silencing were tested both in vitro and in vivo for prostate cancer PC3 models. Significant reduction in cancer cell survival was observed due to cell cycle arrest and apoptosis when mTOR silencing was induced in vitro. mTOR silencing also caused tumor regression for the early-staged PC3 tumors (100% tumor regressed and 45% became tumor-free). The advanced-staged tumors also demonstrated significant responses (100% regressed). Therefore, our results demonstrate the powerful utility of this new inducible xenograft tumor model for efficacy evaluation of cancer targets, and it provides a direct in vivo efficacy validation of mTOR as a cancer therapeutic target.

A novel RNAi library based on partially randomized consensus sequences of nuclear receptors: Identifying the receptors involved in amyloid β degradation

Combinatorial gene inactivation using an RNAi library is a powerful approach to discovering novel functional genes. However, generation of a comprehensive RNAi library remains technically challenging. In this report, we describe a simple and novel approach to designing gene-family-specific RNAi libraries by targeting conserved motifs using degenerate oligonucleotides. We created an siRNA library in the pHUMU vector using partially randomized sequences targeting the consensus region in the ZnF_C4 signature motif of the nuclear hormone receptors and thus against the entire receptor superfamily. For proof of principle, we adapted a reporter assay to screen this library for receptors that might be involved in reducing amyloid beta peptide accumulation. We modified a previously described luciferase reporter assay to measure the amyloid beta precursor cleavages occurring only between beta- and gamma-secretase cleavage sites, thus excluding the major gamma-secretase activities that could generate neurotoxic Abeta peptides. Our screen using this assay identified siRNA vectors that specifically increase the Abeta40/42 cleavage and pointed to a potential receptor target, ROR-gamma. SiRNAs targeting other regions of ROR-gamma not only confirmed the observed reporter activity but also reduced the level of the toxic Abeta peptides. The results demonstrated a general principle for the creation and application of this RNAi library approach for functional gene discovery within a predefined protein family. The discovered negative effect of ROR-gamma on the degradation of the toxic Abeta peptides may also provide a potential drug target or targetable pathway for intervention of Alzheimer disease.

NR4A1, 2, 3--an orphan nuclear hormone receptor family involved in cell apoptosis and carcinogenesis

Three members of the NR4A1/Nur77/ NGFIB orphan nuclear hormone receptor subfamily (NR4A1, NR4A2, and NR4A3) belong to the steroid nuclear hormone receptor superfamily. They share similar structural features and have no known natural ligand. They constitute immediate early genes that are induced by serum, growth factors and receptor engagement and are thus implicated in cell mitogenic responses. These nuclear receptors are transcription factors that exert their functions through activation and subsequent induction of the downstream pathways. They have been shown to play a role in complex pathways of cell survival and apoptosis. Although the expression of these genes have been shown to be pro-survival, it has also been reported that NR4A1 expression can cause apoptosis. These two opposite effects apparently result from distinct mechanisms: either transcriptional activation of genes responsible for cell survival or cell apoptosis, or translocation into the cytoplasm where they target the mitochondria and cause cell apoptosis via Bcl-2 binding. The latter mechanism constitutes a new paradigm of cellular apoptosis. In vitro functional studies using over-expression (gain of function) or gene inactivation (loss of function) type assays, combined with transgenic or knockout animal data in vivo, have revealed these effects and their physiological roles, including thymocyte development for NR4A1/3 and pro-survival in CNS for NR4A2. Recent studies have also suggested an important role of these receptors in cell transformation and tumorigenicity via both their anti-apoptotic and pro-apoptotic functions. In particular, the recent identification of a functional ligand for NR4A1 suggests that these members could potentially serve as drug targets for disease indications such as cancer. While many aspects of these receptors have been previously reviewed, this article focuses on new experimentation and discovery of their apoptotic and carcinogenic roles, and discusses their potential roles as therapeutic targets.

PHTS, a novel putative tumor suppressor, is involved in the transformation reversion of HeLaHF cells independently of the p53 pathway

HeLaHF is a non-transformed revertant of HeLa cells, likely resulting from the activation of a putative tumor suppressor(s). p53 protein was stabilized in this revertant and reactivated for certain transactivation functions. Although p53 stabilization has not conclusively been linked to the reversion, it is clear that the genes in p53 pathway are involved. The present study confirms the direct role of p53 in HeLaHF reversion by demonstrating that RNAi-mediated p53 silencing partially restores anchorage-independent growth potential of the revertant through the suppression of anoikis. In addition, we identified a novel gene, named PHTS, with putative tumor suppressor properties, and showed that this gene is also involved in HeLaHF reversion independently of the p53 pathway. Expression profiling revealed that PHTS is one of the genes that is up-regulated in HeLaHF but not in HeLa. It encodes a putative protein with CD59-like domains. RNAi-mediated PHTS silencing resulted in the partial restoration of transformation (anchorage-independent growth) in HeLaHF cells, similar to that of p53 gene silencing, implying its tumor suppressor effect. However, the observed increased transformation potential by PHTS silencing appears to be due to an increased anchorage-independent proliferation rate rather than suppression of anoikis, unlike the effect of p53 silencing. p53 silencing did not affect PHTS gene expression, and vice versa, suggesting PHTS may function in a new and p53-independent tumor suppressor pathway. Furthermore, over-expression of PHTS in different cancer cell lines, in addition to HeLa, reduces cell growth likely via induced apoptosis, confirming the broad PHTS tumor suppressor properties.

A 96-Well Surrogate Survival Assay Coupled with a Special Short Interfering RNA Vector for Assessing Cancer Gene Targets with Enhanced Signal/Noise Ratio and Its Utility in HTS for Cancer Therapeutic Targets

Transient transfection of short interfering RNAs to inactivate cancer therapeutic genes in cancer cells is an important method to induce therapeutic phenotypes (cell apoptosis, growth arrest, etc.) for cancer target validation. These phenotypes can be initially assessed by cell survival via colorimetric/fluorescence readings, e.g., alamarBlue (Trek Diagnostic Systems, Cleveland, OH) and WST-1. However, intrinsic problems exist for transient transfection-varying toxicity, inconsistent transfection efficiency, as well as other cell-specific determinants-which contribute to a low signal:noise ratio of the assays, rendering of the assay ineffective particularly when applied in high-throughput screening (HTS) multiplexed for different cells. This report describes a method using reporter as a "normalized surrogate" for the conventional survival readout in a 96-well format. In this approach, only the transfected surviving cells produce reporter activities, and many variables associated with transient transfection are excluded. A constitutively expressed reporter gene (luciferase or LacZ) expression cassette is co-transfected into cells along with a specially designed RNA interference (RNAi) vector (or a transgene for that matter). The reporter activity in either liquid cultures or in soft agar cultures in 96-well formats is then quantitated in situ. The RNAi vector construction is simplified so that it can be adapted to a 96-well format. Our data demonstrated that the relative reporter readings for survival are independent of both transfection efficiency and cellular toxicity. The signal:noise ratio is markedly increased, particularly for cells with low transfection efficiency. The assay is versatile and robust and can be applied in multiplexed HTS for cancer target identification and validation.

Nuclear Hormone Receptor NR4A2 Is Involved in Cell Transformation and Apoptosis

HeLaHF cells are transformation revertants of cervical cancer HeLa cells and have lost anchorage-independent growth potential and tumorigenicity. Activation of tumor suppressor(s) was implicated previously in this transformation reversion. In this study, expression profiling analysis was carried out to identify potential oncogenes that are down-regulated in HeLaHF cells. We found that all three members of the NR4A1/Nur77/NGFIB orphan nuclear hormone receptor subfamily (NR4A1, NR4A2, and NR4A3) were down-regulated in the HeLaHF revertant. Small interfering RNA-mediated down-regulation of NR4A2 in HeLa cells, either transiently or stably, resulted in reduced anchorage-independent growth that was largely attributable to increased anoikis. Furthermore, down-regulation of NR4A2 as well as NR4A1 promoted intrinsic apoptosis. These phenotypes were also observed in several other experimental cancer cells, suggesting the observed apoptosis suppression is a more general property of NR4A2 and NR4A1. These phenotypes also suggest that the Nur77/NGFIB subfamily of orphan receptors exhibit certain oncogenic functionalities with regards to cell proliferation and apoptosis and could therefore be evaluated as potential cancer therapeutic targets.

BI-1 Regulates an Apoptosis Pathway Linked to Endoplasmic Reticulum Stress

Bax inhibitor-1 (BI-1) is an evolutionarily conserved endoplasmic reticulum (ER) protein that suppresses cell death in both animal and plant cells. We characterized mice in which the bi-1 gene was ablated. Cells from BI-1-deficient mice, including fibroblasts, hepatocytes, and neurons, display selective hypersensitivity to apoptosis induced by ER stress agents (thapsigargin, tunicamycin, brefeldin A), but not to stimulators of mitochondrial or TNF/Fas-death receptor apoptosis pathways. Conversely, BI-1 overexpression protects against apoptosis induced by ER stress. BI-1-mediated protection from apoptosis induced by ER stress correlated with inhibition of Bax activation and translocation to mitochondria, preservation of mitochondrial membrane potential, and suppression of caspase activation. BI-1 overexpression also reduces releasable Ca(2+) from the ER. In vivo, bi-1(-/-) mice exhibit increased sensitivity to tissue damage induced by stimuli that trigger ER stress, including stroke and tunicamycin injection. Thus, BI-1 regulates a cell death pathway important for cytopreservation during ER stress.

One-week 96-well soft agar growth assay for cancer target validation

Soft agar growth, used to measure cell anchorage-independent proliferation potential, is one of the most important and most commonly used assays to detect cell transformation. However, the traditional soft agar assay is time-consuming, labor-intensive, and plagued with inconsistencies due to individual subjectivity. It does not, therefore, meet the increasing demands of today's oncology drug target screening or validation processes. This report describes an alternative 96-well soft agar growth assay that can function as a replacement for the traditional method and overcomes the aforementioned limitations. It offers the following advantages: a shortened assay duration (1 week instead of 4 weeks) that makes transient transfection or treatment possible; plate reader quantification of soft agar growth (measuring cloning efficiency and colony size); and a significant reduction in required labor. Higher throughput also makes it possible to process large numbers of samples and treatments simultaneously and in a much more efficient manner, while saving precious workspace and overall cost.

Evolutionarily conserved cytoprotection provided by Bax Inhibitor-1 homologs from animals, plants, and yeast

Programmed cell death (PCD) plays important roles in the development and physiology of both animals and plants, but it is unclear whether similar mechanisms are employed. Bax Inhibitor-1 (BI-1) is an intracellular multi-membrane-spanning protein and cell death inhibitor, originally identified by a function-based screen for mammalian cDNAs capable of suppressing cell death in yeast engineered to ectopically express the pro-apoptotic protein Bax. Using this yeast assay, we screened expression libraries for cDNAs from the plant, Lycopersicon esculentum (tomato), and the invertebrate animal Drosophila melanogaster (fruit fly), identifying close homologs of BI-1 as Bax-suppressors. We studied the fly and tomato homologs of BI-1, as well as BI-1 homologs identified in Arabidopsis thaliana, Oryza sativa (rice), and Saccharomyces cerevisiae (budding yeast). All eukaryotic homologs of BI-1 blocked Bax-induced cell death when expressed in yeast. Eukaryotic BI-1 homologs also partially rescued yeast from cell death induced by oxidative stress (H(2)O(2)) and heat shock. Deletion of a C-terminal domain from BI-1 homologs abrogated their cytoprotective function in yeast, demonstrating conserved structure-function relations among these proteins. Expression of tomato BI-1 by agroinfiltration of intact plant leaves provided protection from damage induced by heat-shock and cold-shock stress. Altogether, these findings indicate that BI-1 homologs exist in multiple eukaryotic species, providing cytoprotection against diverse stimuli, thus implying that BI-1 regulates evolutionary conserved mechanisms of stress resistance that are germane to both plants and animals.

Characterization of the anti-apoptotic mechanism of Bcl-B

Bcl-B protein is an anti-apoptotic member of the Bcl-2 family protein that contains all the four BH (Bcl-2 homology) domains (BH1, BH2, BH3 and BH4) and a predicted C-terminal transmembrane domain. Our previous results showed that Bcl-B binds Bax and suppresses apoptosis induced by over-expression of Bax; however, Bcl-B does not bind or suppress Bak. To explore the molecular basis for the differential binding and suppression of Bax and Bak, we studied the BH3 dimerization domains of Bax and Bak. Chimeric mutants of Bax and Bak were generated that swapped the BH3 domains of these pro-apoptotic proteins. Bcl-B associated with and blocked apoptosis induced by mutant Bak containing the BH3 domain of Bax, but not mutant Bax containing the BH3 domain of Bak. In contrast, Bcl-X(L) protein bound and suppressed apoptosis induction by Bax, Bak and both BH3-domain chimeras. A strong correlation between binding and apoptosis suppression was also obtained using a series of alanine substitutions spanning the length of the Bax BH3 domain to identify critical residues for Bcl-B binding. Conversely, using structure-based modelling to design mutations in the BH3-binding pocket of Bcl-B, we produced two Bcl-B mutants (Leu86-->Ala and Arg96-->Gln) that failed to bind Bax and that also were unable to suppress apoptosis induced by Bax over-expression. In contrast, other Bcl-B mutants that still bound Bax retained protective activity against Bax-induced cell death, thus serving as a control. We conclude that, in contrast with some other anti-apoptotic Bcl-2-family proteins, a strong correlation exists for Bcl-B between binding to pro-apoptotic multidomain Bcl-2 family proteins and functional apoptosis suppression.