Evidence for APOBEC3B mRNA and protein expression in oral squamous cell carcinomas.
It has been demonstrated that APOBEC3B possesses cytidine deaminase activity, which is likely to result in C-to-T signature mutations. Increased expression of the APOBEC3B gene has been shown to correlate with higher incidence of such mutations in various cancer types, such as breast, bladder, lung, and head and neck carcinomas. In the current study, we used in silico methods, immunohistochemistry and qRT-PCR to detect the presence of APOBEC3B signature mutations and examine the levels and patterns of APOBEC3B expression in oral squamous cell carcinomas (OSCCs). Using the Cancer Genome Atlas (TCGA) database, we have found a high incidence of C-to-T transitions in head and neck squamous cell carcinomas (HNSCCs), of which OSCCs constitute the largest subgroup. Additionally, we compared APOBEC3B expression, at both mRNA and protein level, between OSCCs and non-cancerous samples. APOBEC3B was detected in both groups, but nuclear localization was consistent only in normal oral cells. APOBEC3B mRNA levels were clearly higher in OSCCs than in controls. These results suggest that while in normal oral cells APOBEC3B has an important nuclear function to fulfill, this activity may be hindered in a subgroup of tumor cells, due to the more prominent localization of the enzyme in the cytoplasm.
Department of Oral Biology, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece. Electronic address: gfanourak@med.uoa.gr.
Galinos
G
Fanourakis
Department of Oral Pathology, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Konstantinos
K
Tosios
Division of Basic Sciences, School of Medicine, University of Crete, Heraklion, Greece.
Nikolaos
N
Papanikolaou
Department of Basic Sciences, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Ioulia
I
Chatzistamou
Laboratory of Nuclear Proteins and Chromatin Function, Institute of Biosciences and Applications, National Center for Scientific Research (NCSR) "Demokritos", Athens, Greece.
Marios
M
Xydous
1st Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
Sofia
S
Tseleni-Balafouta
Department of Oral Pathology, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Alexandra
A
Sklavounou
Laboratory of Environmental Mutagenesis and Carcinogenesis, Institute of Biosciences and Applications, National Center for Scientific Research (NCSR) "Demokritos", Athens, Greece.
Gerassimos E
GE
Voutsinas
Department of Oral Biology, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Heleni
H
Vastardis
D021581:Active Transport, Cell Nucleus; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism; D003564:Cytidine Deaminase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008875:Middle Aged; D015778:Minor Histocompatibility Antigens / Q000235:genetics* / Q000378:metabolism; D009062:Mouth Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D015778:Minor Histocompatibility Antigens; D012333:RNA, Messenger; C495794:APOBEC3B protein, human; D003564:Cytidine Deaminase
APOBEC3B; Genomics; Head and neck squamous cell carcinoma; Immunohistochemistry; Oral squamous cell carcinoma