Quantitative analysis of proliferation, apoptosis, and angiogenesis in retinoblastoma and their association with the clinicopathologic parameters

Expression of Ki67 as detected by MIB-1 and its association with histopathological high-risk factors among patients with retinoblastoma tumour: a cross-sectional study

Objectives

This study aims to investigate the expression of Ki67 in formalin-fixed paraffin-embedded tissue blocks from patients with a diagnosis of retinoblastoma tumour (RbT) as well as determining its association with histopathological high-risk factors (HHRFs).

Methods and analysis

Retrospectively, a total of 194 eyeball specimens from 163 children with RbT were reviewed at Muhimbili National Hospital between 2009 and 2013. Immunohistochemical expression of Ki67 using MIB-1 antibody (Abcam, batch ab93680, Cambridge, UK) was determined and correlated with the conventional HHRFs. The predictors of Ki67 expression were determined using binary logistic regression model in multivariate analysis. A two-tailed p<0.05 was considered statistically significant.

Results

Majority (67.5%) of the patients had leukocoria and extraocular disease was found in 20.9% of all the patients. High expression of Ki67 was present in 63.8% of the 80 eyeballs that were tested. Massive choroidal invasion (adjusted OR (AOR)=9.32, 95% CI=2.82 to 10.89), positive retrolaminar optic nerve invasion (AOR=3.01, 95% CI=4.43 to 9.11), positive surgical margin (AOR=7.10, 95% CI=1.63 to 11.40) and pT4 (AOR=7.49, 95% CI=0.12 to 0.89) were the potential HHRFs that were associated with Ki67 overexpression.

Conclusion

Overexpression of Ki67 may be of prognostic value for patients with RbT as it has been shown in the present study that high expression was common in tumours with massive choroidal invasion, positive retrolaminar optic nerve invasion, positive surgical margin and advanced tumour stage, which are the conventional HHRFs associated with prognosis of RbT.

Clinicopathological Findings of Retinoblastoma: A 10-Year Experience from a Tertiary Hospital in Kampala, Uganda

Background

Retinoblastoma (RB) is one of the most common cancers occurring in young children in sub-Saharan Africa. The incidence rate reported in the literature is 9,000 new cases per year, which corresponds to 1 in 15,000 births. This study aimed at analyzing the clinicopathological findings in children with RB in Uganda.

Purpose

The purpose of this study was to describe and analyze the clinicopathological findings in the patients with RB.

Design

This was a cross-sectional analytical study involving 234 eyeball surgical specimens from 214 patients with RB diagnosed between January 2006 and December 2015.

Results

The mean age of the patients was 27.8 months (SD = 21.413, range: 1–132 months). More than half of the cases, 50.9%, presented with leucokoria. Invasion of choroid, sclera, anterior chamber, and optic nerve was found in 26.5% (n = 58), 51.2% (n = 88), 26.2% (n = 45), and 29.2% (n = 49), respectively. Twenty-six percent (n = 56) of the cases with intraocular tumour were at stage I and all patients with metastasis 4.7% (n = 11) had stage IV. The correlation between postlaminar optic nerve invasion and massive choroidal invasion was statistically significant (P = 0.002). Also, there was a statistical significance difference between metastasis and postlaminar invasion (P = 0.004).

Conclusion

The majority of children with RB in Uganda present clinically with leucokoria, and their parents or guardians seek medical intervention at a later stage. Moreover, there was a noticeably significant lag period for the patients to begin treatment after the diagnosis was done.

PEGylated immunoliposome-loaded endoglin single-chain antibody enhances anti-tumor capacity of porcine α1,3GT gene

Tumor could not be completely removed due to the absence of immune storm against tumor. The porcine α1,3 galactosyltransferase (α1,3 GT) induce the hyperacute rejection by synthesizing Galα1-3Galβ1-(3)4GlcNAc-R (αGal) on the surface of graft endothelial cells (ECs) during xeno-transplantation. This study aimed to develop anti-endoglin single-chain Fv fragments (ENG-scFv) conjugated PEGylated immunoliposomes (iLPs) to induce immune storm against tumor. Immune fluorescence was performed to detect the binding of ENG-scFv to human ENG, the endosomal/lysosomal escape of ENG-scFv-iLPs/α1,3 GT, and αGal expression in hENG-HEK293 cells. In vitro MTT assay was performed to measure ENG-scFv-iLPs/α1,3 GT cytotoxicity. NOD/SCID mouse born A549 tumor model was used to evaluate the therapeutic potency of ENG-scFv-iLPs/α1,3 GT. ENG-scFv-iLPs enabled efficient targeting delivery of α1,3 GT plasmid to ENG + tumors neovascular endothelial cells (TnECs), promoted endosomal/lysosomal escape due to the pH-sensitive ability, then synthesized carbohydrate epitope αGal on the surface of these cells to achieve the purpose of destroying the tumor. The mechanism of uptake for nanoparticles was energy driven, the clathrin-mediated endocytosis was the main endocytic pathway of the ENG-mAb-iLPs/α1,3 GT and lipid-raft-mediated of the ENG-scFv-iLPs/α1,3 GT, and macropinocytosis was also involved in intracellular entry. The inhibition of tumor angiogenesis and proliferation by ENG-scFv-iLPs/α1,3 GT was closely related to down-regulation of VEGF. Our findings establish an alternative therapeutic paradigm for scFv-conjugated nanoparticles to induce tumor cell apoptosis and inhibit tumor growth early. Such iLPs nanocarrier could efficiently release α1,3 GT to their distinct sites of action, where the endoglin + tumor neovascular endothelial cells (ENG + TnECs) exist, in a site-specific manner. Therefore, we believe that these scFv-targeted core-shell immunocomplexes are an important potential α1,3 GT delivery system for various solid tumor-targeted therapy.

PRC1 gene silencing inhibits proliferation, invasion, and angiogenesis of retinoblastoma cells through the inhibition of the Wnt/β-catenin signaling pathway

Retinoblastoma is an ocular malignancy occurring in childhood. The current study evaluates the ability of silenced PRC1 on retinoblastoma cell proliferation, and angiogenesis via the Wnt/β-catenin signaling pathway. A total of 36 cases of retinoblastoma tissues (n = 36) and normal retinal tissues (n = 10) were selected in the current study. Retinoblastoma cells presenting with the high PRC1 messenger RNA (mRNA) expression were selected among the WERI-Rb-1, HXO-RB44, Y79, SO-Rb50, and SO-Rb70 cells lines, and were transfected with siRNA-PRC1 and LiCl (the activator of the Wnt/β-catenin pathway). The expressions of PRC1, VEGF, Wnt1, β-catenin, CyclinD1, extent of β-catenin, and GSK-3β phosphorylation were evaluated. Cell proliferation, cell-cycle distribution, and cell invasion of retinoblastoma cells were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and Transwell assay. The angiogenesis of retinoblastoma cells was detected by tube formation assay. HXO-RB44 and WERI-Rb-1 cells were selected owing to the highest PRC1 mRNA expression. Meanwhile, PRC2 gene silencing presented lower expression levels of PRC1, VEGF, Wnt1, β-catenin, CyclinD1, extent of β-catenin and GSK-3β phosphorylation, decreased proliferation and invasion abilities, extended G0/G1 phase, and shortened S and G2/M phases of HXO-RB44 and WERI-Rb-1 cells, suggesting the silenced PRC2 inactivated Wnt/β-catenin pathway, so as to further restrain the retinoblastoma cell proliferation, invasion, and angiogenesis. These results support the view that PRC1 gene silencing could suppress the proliferation, and angiogenesis of retinoblastoma cells by repressing the Wnt/β-catenin pathway.

Correlation of microvascular density and proliferation index in undifferentiated nasopharyngeal carcinoma

Background: Undifferentiated nasopharyngeal carcinoma is a highly malignant tumor with an endemic distribution. Several histologic parameters have been studied to provide prognostic information for patient management. Both proliferation index and microvascular density are commonly determined on such tumors, but the relationship between these two parameters has not been studied fully. Objectives: Determine the association between microvascular density and cellular proliferation in undifferentiated nasopharyngeal carcinoma. Methods: A series of 60 cases were studied in patients of Southeast Asian origin. Cellular proliferation was determined using Ki67 immunostaining, and vessel proliferation using CD31 immunostaining in terms of areas of increased staining (‘hot spots’). Ki67 results were scored on a scale of 0-4+ and CD31 results as a microvascular density/mm2. Results: The mean of the microvascular density was 22/mm2 in the Ki67-negative group (25 cases). In the Ki67- positive group (35 cases), the mean was 35/mm2. The difference between the positive and negative group was statistically significant (p <0.001). Microvascular density significantly increased as the Ki67 score increased (p<0.001). However, the ‘hot spots’ for microvascular density in tissue sections did not correspond to areas of increased cellular proliferation. Conclusion: Pathologists usually determine only one of these two prognostic factors when dealing with undifferentiated nasopharyngeal carcinoma. The proliferation index is suggested because it is easier to perform and can be done on small biopsies not to contain enough surface area for microvascular density determination.

Immunohistochemistry of apoptosis-related proteins in retinoblastoma

Retinoblastoma is the most common intraocular malignant neoplasia during childhood and results from the partial or total inactivity of the retinoblastoma protein (pRb). In the absence of pRb, the E2F transcription factors increase the levels of cell cycle proteins as well as some pro-apoptotic proteins. We intended to study the immunohistochemistry profile of apoptotic-related proteins in retinoblastoma. We also evaluated the association between the expression of apoptotic protein and stage of tumor or survivor after a 5year follow up. Apoptosis-related proteins (Apaf-1, Bak, Bax, Bcl-2, Bcl-xL, Bim-long, MDM2, p53, pro-caspase-3, PUMA, Smac/DIABLO and cleaved caspase-3) were evaluated using immunohistochemistry on tissue microarrays which contained samples of retinoblastoma tumors taken from ninety-three patients without any treatment previous to surgery. The immunohistochemistry reactions were evaluated using an optical microscope as well as the ACIS III^® platform. The pro-apoptotic proteins (APAF-1, Bax, p53, PUMA, Smac/DIABLO) were more frequently expressed than the anti-apoptotic proteins (Bcl-2, Bcl-xL and MDM2). The protein Bcl-xL had a negative correlation with cleaved caspase-3, a marker of cell apoptosis. Bcl-xL may be implicated in an apoptosis block.

Microultrasound and its application to longitudinal studies of mouse eye development and disease

Microultrasound imaging is a flexible high-resolution real-time in vivo imaging modality based on the transmission and the reception of ultrasound waves. Because of its high temporal (>250 Hz) and spatial (30-150 µm) resolutions and the noninvasive nature of ultrasound, microultrasound is used extensively in preclinical research to monitor functional and dynamic phenotypic changes in small animal models. Its ability to perform in vivo longitudinal monitoring of development, pathology, and therapeutic effectiveness is particularly advantageous. This article reviews the technology and the applications of high-frequency microultrasound for the study of mouse eye development from embryonic day E11.5 to postnatal day P16. Procedures for animal handling and scanning are given, and applications are described in the context of ocular development and disease. Quantitative analysis of the growth kinetics of the lens and the orbit is discussed. In addition, mouse models of retinoblastoma and glaucoma are followed as a function of disease progression to reveal their associated morphological and functional traits. Microultrasound is performed with high-frequency imaging equipment (from VisualSonics) operating at center frequencies between 15 and 50 MHz. These instruments provide both anatomical imaging as well as functional and molecular analyses of the living mouse.

Gelatinase expression in retinoblastoma: modulation of LH(BETA)T(AG) retinal tumor development by anecortave acetate

PURPOSE

Gelatinases, matrix metalloproteinase (MMP)-2, and MMP-9 are known for their importance in angiogenesis and tumor biology. The purpose of this study was to test the hypothesis that anecortave acetate (AA) decreases transgenic retinoblastoma (RB) tumor burden by modulating gelatinase activity.

METHODS

To assess the possible gelatinase modulation after AA treatment, a single subconjunctival injection of AA (300 microg) was delivered to the right eyes of 10-week-old LH(BETA)T(AG) mice. Eyes were evaluated for gelatinase expression and activity by gel and in situ zymography at 24 hours, 48 hours, and 1 week after treatment.

RESULTS

Gel zymography of whole eye extracts and in situ zymography of retinal tumors showed strong gelatinase expression and activity within transgenic RB tumors. AA treatment in RB transgenic mice resulted in a significant decrease of gelatinase activity 1 week after AA treatment. Surprisingly, there was an initial transient upregulation of MMP-9 activity in whole eye extracts at 24 and 48 hours after AA treatment in both LH(BETA)T(AG) transgenic and wild-type mice. This increase was not observed in the tumors.

CONCLUSIONS

As suggested by our data, inhibition of gelatinase activity appears to be a mechanism of action of AA. AA treatment results in a decrease in gelatinase activity that correlates with the significant decrease in tumor burden shown by the authors' previous studies. However, the significance of the initial, transient upregulation of gelatinase by AA injection is unknown, and further studies are warranted. Combining antiangiogenic agents with multiple mechanisms of action has the potential to enhance RB tumor control.

Heterogeneous tumor vasculature in retinoblastoma: implications for vessel targeting therapy

PURPOSE

The aim of this study is to correlate tumor size of retinoblastoma tumor samples with blood vessel maturation to assess how these factors may affect vessel targeting therapy.

METHODS

Analysis was performed on retinoblastoma tumor specimens (n = 5) enucleated as primary treatment from May 2005 to February 2006. Tumor size was measured as the largest cross sectional area of the tumor, measured during pathologic assessment. Vessel density and heterogeneity was measured by immunohistochemical analysis. Total microvessel density was detected by staining endothelial cells using a lectin from Bandeira simplicifolia; novel vasculature was detected with the endothelial cell marker endoglin (CD105). Blood vessel basement membrane was detected with an antibody against type IV collagen. Vessel maturation was assessed by pericyte recruitment, detected with alpha smooth muscle actin (alpha-sma).

RESULTS

A statistically significant correlation was detected between tumor burden and age at enucleation (P = 0.008). All retinoblastoma tumor samples harbored a high degree of blood vessel heterogeneity containing both immature neovessels as well as pericyte-committed mature vasculature. There was a statistically significant correlation between type IV collagen and age at enucleation (P = 0.045).

CONCLUSIONS

This study provides a framework for a better understanding of tumor and vessel development in retinoblastoma. Results of this study provide insight into the relationship between age and tumor burden in these tumors. Knowledge of the degree of heterogeneity detected in these tumors will aid in the selection of novel blood vessel targeting strategies for children with this disease and other diseases with pathologic neovascularization.