Expression of cyclooxygenase-2 mRNA alternative splice variant in human cervical carcinoma tissues

ABSTRACT

BACKGROUND:

Cervical cancer is one of the most frequent malignancies in women worldwide, and its occurrence and development is closely related to cyclooxygenase-2 (COX-2).

To examine the expression of COX-2 alternative splicing variants in human cervical carcinoma tissue and understand its possible implications.

Non-randomized controlled experiment.

Key Laboratory of Biochemistry and Molecular Pharmacology,Department of Obstetrics and Gynecology, First Affiliated Hospital,Chongqing Medical University.

Carcinoma tissue and normal tissue were obtained from 13 cervical carcinoma patients admitted during March 2002 to April 2002in the Department of Obstetrics and Gynecology, First Affiliated Hospital,Chongqing Medical University.

A pair of specific primers were designed for reverse transcription-polymerase chain reaction (RT-PCR) to obtain the mRNA of COX-2 in human cervical carcinoma tissues. The resultant band on electrophoresis was cloned, sequenced and analyzed.MAIN OUTCOME

① Agarose gel electrophoresis result of the PCR product of carcinoma and normal tissues; ② Sequencing result of the electrophoresis band from carcinoma and normal tissues.

No COX-2 band (252 bp) was found in electrophoresis for normal tissues, while 2 bands appeared for cervical carcinoma tissues, including a new electrophoresis band of 534bp besides the COX-2 band. Cloning and sequencing revealed that this new band contained not only exons 7and 8 of COX-2 gene but also a reserved intron of 282 bp intron between exons 7 and 8. Analysis of the predicted amino acid sequence indicated that an in-frame stop codon occurred in the 48-50 bp of the intron retained in the mRNA.

The presence of COX-2 alternative splicing mRNA variant (Genbank accession numberBU493602)is confirmed in human cervical carcinoma tissue, which codes for a protein possibly smaller than COX-2.