Molecular Biomarkers Detected Using Fluorescence in situ Hybridization in a Filipino with Retinoblastoma.

Background and Objective: Retinoblastoma is one of the most common intraocular cancers among children usually caused by the loss of retinoblastoma protein function. Despite being a highly heritable disease, conventional diagnostic and prognostic methods depend on clinical examination, with limited consideration of cancer genetics in the standard of care. CD133, KRT19, and MUC1 are commonly explored genes for their utility in liquid biopsies of cancer including lung adenocarcinoma. To date, there are few extensive molecular studies on retinoblastoma in Filipino patients. To this end, the study aimed to describe the copy number of CD133, KRT19, and MUC1 in retinoblastoma samples from a Filipino patient and quantitate the respective expression level of these genes. Methods: Hematoxylin & Eosin (H&E) staining was utilized to characterize the retinoblastoma tissue while fluorescence in situ hybridization (FISH) using probes specific to CD133, KRT19, and MUC1 was performed to determine the copy number of genes in retinoblastoma samples from a Filipino patient (n = 1). The gene expression of CD133, MUC1, and KRT19 was quantitated using RT-qPCR. Results: The H&E staining in the retinoblastoma tissue shows poorly differentiated cells with prominent basophilic nuclei. CD133 was approximately 1.5-fold overexpressed in the retinoblastoma tissue with respect to the normal tissue, while MUC1 and KRT19 are only slightly expressed. Multiple intense signals of each probe were localized in the same nuclear areas throughout the retinoblastoma tissue, with high background noise. Conclusion: These findings suggest that CD133 is a potential biomarker for the staging and diagnosis of retinoblastoma in Filipino cancer patients. However, further optimization of the hybridization procedures is recommended.

The effects of immortalization on the N-glycome and proteome of CDK4-transformed lung cancer cells.

Biological experiments are often conducted in vitro using immortalized cells due to their accessibility and ease of propagation compared to primary cells and live animals. However, immortalized cells may present different proteomic and glycoproteomic characteristics from the primary cell source due to the introduction of genes that enhance proliferation (e.g. CDK4) or enable telomere lengthening. To demonstrate the changes in phenotype upon CDK4-transformation, we performed LC-MS/MS glycomic and proteomic characterizations of a human lung cancer primary cell line (DTW75) and a CDK4-transformed cell line (GL01) derived from DTW75. We observed that the primary and CDK4-transformed cells expressed significantly different levels of sialylated, fucosylated, and sialofucosylated N-glycans. Specifically, the primary cells expressed higher levels of hybrid- and complex-type sialylated N-glycans, while CDK4-transformed cells expressed higher levels of complex-type fucosylated and sialofucosylated N-glycans. Further, we compared the proteomic differences between the cell lines and found that CDK4-transformed cells expressed higher levels of RNA-binding and adhesion proteins. Further, we observed that the CDK4-transformed cells changed N-glycosylation after 31 days in cell culture, with a decrease in high-mannose and increase in fucosylated, sialylated, and sialofucosylated N-glycans. Identifying these changes between primary and CDK4-transformed cells will provide useful insight when adapting cell lines that more closely resemble in vivo physiological conditions.