Human Ribosomal Proteins RPeL27, RPeL43, and RPeL41 Are Upregulated in Nasopharyngeal Carcinoma Cell Lines

Abstract

Apart from their canonical role in ribosome biogenesis, there is increasing evidence of ribosomal protein genes' involvement in various cancers. A previous study by us revealed significant differential expression of three ribosomal protein genes (RPeL27, RPeL41, and RPeL43) between cell lines derived from tumor and normal nasopharyngeal epithelium. However, the results therein were based on a semiquantitative assay, thus preliminary in nature. Herein, we provide findings of a deeper analysis of these three genes in the context to nasopharyngeal carcinoma (NPC) tumorigenesis. Their expression patterns were analyzed in a more quantitative manner at transcript level. Their protein expression levels were also investigated. We showed results that are contrary to previous report. Rather than downregulation, these genes were significantly overexpressed in NPC cell lines compared to normal control at both transcript and protein levels. Nevertheless, their association with NPC has been established. Immunoprecipitation pulldown assays indicate the plausible interaction of either RPeL27 or RPeL43 with POTEE/TUBA1A and ACTB/ACTBL2 complexes. In addition, RPeL43 is shown to bind with MRAS and EIF2S1 proteins in a NPC cell line (HK1). Our findings support RPeL27, RPeL41, and RPeL43 as potential markers of NPC and provide insights into the interaction targets of RPeL27 and RPeL43 proteins.

TheuS8,uS4,eS31, anduL14Ribosomal Protein Genes Are Dysregulated in Nasopharyngeal Carcinoma Cell Lines

“…In summary, our studies reveal the significant downregulation of three 40S RP genes ( eS8, uS4 , and eS31 ) and a 60S RP gene (uL14) in NPC cell lines. Our findings reinforce previous reports [ 25 , 26 ] on the occurrence of dysregulated expression among a subset of ribosomal protein genes in NPC. The differential expression pattern of eS8, uS4 , eS31 , and uL14 is revealed for the first time in the NPC context and, hence, adds to the list of possible NPC-associated RP factors.…”

“…These two RP genes were downregulated in tumors of NPC relative to normal controls [ 24 ]. Three other genes ( eL27 , eL41 , and eL43 ) were later proven to be NPC-associated RP factors in cell lines derived from NPC tissues [ 25 , 26 ]. However, the hypothesis of eS26 and eS27 as NPC-associated RP genes was subsequently refuted [ 27 ].…”

Diagnostic and prognostic implications of ribosomal protein transcript expression patterns in human cancers

“…Perturbations of several individual RPs have been found in numerous human cancers, including those of the breast, pancreas, bladder, brain and many other tissues [ 13 – 25 ]. Mutations and deletions of RP-encoding genes have also been found in endometrial cancer, colorectal cancer, glioma, and various hematopoietic malignancies [ 26 – 28 ].…”

Biological effect of ribosomal protein L32 on human breast cancer cell behavior

“…However, it has been revealed that certain RPs are expressed in tissue-specific patterns and can differentially contribute to ribosome composition, affect ribosomal RNA processing and regulate translation ( 10 ). Previous studies have reported that perturbations of several individual RPs occur in numerous types of human cancer, including cancer of the brain, pancreas, bladder and other tissues ( 11 – 17 ). These studies have rapidly established mutations in RPs as a novel, underexplored class of oncogenic factors.…”