HOXC6 is deregulated in human head and neck squamous cell carcinoma and modulates Bcl-2 expression.
Homeobox C6 (HOXC6) genes belong to the homeoprotein family of transcription factors, which play an important role in morphogenesis and cellular differentiation during embryonic development. The aim of this study was to explore the role of HOXC6 in the regulation of Bcl-2 in human head and neck squamous cell carcinoma (HNSCC). The HOXC6 and Bcl-2 gene were identified as being overexpressed in HNSCC tissue and cell lines. Transfection assays demonstrated that HOXC6 increased the levels of Bcl-2 mRNA and protein. A luciferase reporter assay suggested that HOXC6 induced activity of the Bcl-2 promoter. A series of Bcl-2 promoter deletion mutants were examined and the minimal HOXC6-responsive region was identified to be in the TAAT motif (-420 bp) of the Bcl-2 promoter. Interestingly, the inhibition of HOXC6 using siRNA led to the repression of Bcl-2 expression and induced caspase-3-dependent apoptosis; overexpression of HOXC6 in HNSCC cells increased the resistance to paclitaxel-induced apoptosis. Together, our findings suggest that HOXC6 is an important mechanism of the anti-apoptotic pathway via regulation of Bcl-2 expression.
Department of Pathology, College of Dentistry, Chosun University, Gwangju, 501-759.
Sung-Min
SM
Moon
Department of Biochemistry, Oriental Medicine, Dongguk University, Gyeongju, 780-714, Republic of Korea.
Soo-A
SA
Kim
Department of Oral Pathology, Daejeon Dental Hospital, Wonkwang University, Daejeon, Republic of Korea, 302-120.
Jung-Hoon
JH
Yoon
Department of Pathology, College of Dentistry, Chosun University, Gwangju, 501-759. Electronic address: ahnsg@chosun.ac.kr.
Sang-Gun
SG
Ahn
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017239:Paclitaxel / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000235:genetics; D020218:Response Elements; D017384:Sequence Deletion
D000972:Antineoplastic Agents, Phytogenic; C094289:HOXC6 protein, human; D018398:Homeodomain Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C505407:CASP3 protein, human; D053148:Caspase 3; D017239:Paclitaxel