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Isolation and partial characterization of a transformation‐associated sequence from human nasopharyngeal carcinoma
Author(s) -
Cao Ya,
Sun Yi,
Poirier Sylvie,
Winterstein Dolores,
Hegamyer Glenn,
Seed John,
Malin Sacha,
Colburn Nancy H.
Publication year - 1991
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940040408
Subject(s) - biology , nasopharyngeal carcinoma , transfection , microbiology and biotechnology , cloning (programming) , clone (java method) , gene , dna , cell culture , genetics , medicine , computer science , programming language , radiation therapy
Abstract A transforming activity associated with Chinese nasopharyngeal carcinoma (NPC) cell line CNE 2 DNA has been identified by transfer into nontransformed promotion‐sensitive mouse JB6(P + ) C141 cells. To clone this transformation‐associated sequence, we carried out three cycles of transfection, followed by cloning of anchorage‐independent transformants in soft agar. A tertiary CNE/JB6 clonal transfectant cell line 625 whose DNA showed transforming activity, as indicated in both soft‐agar assay and nude‐mice implantation, was used to make a genomic library in the vector λ dash. Using the human repeated sequence Blur 8 to screen the library, we obtained 10 human Alu‐positive clones. A cloned Alu‐positive insert of 16 kbp, CNE 323, was characterized in detail. CNE 323 transferred moderate transforming activity when introduced into JB6 P + cells and showed no homology to Ha‐, Ki‐, or N‐ ras genes; human promotion sensitivity genes; src, myb, jun, myc, fos, raf, or int ‐2 oncogenes; or epidermal growth factor receptor. The isolated CNE 323 DNA sequence appeared to preserve the genomic structure of the original sequence found in CNE 2 cells and in nude mouse tumors induced by CNE 2 cells or by CNE/JB6 transfectant cells, indicating that the cloned NPC sequence was activated during NPC carcinogenesis and not during transfection or construction of the library, and that the cloned sequence or a larger sequence of which it was part played a role in tumor formation. Finally, we identified a 1.3‐kb mRNA that hybridizes to a subclone of the 16‐kb NPC sequence in CNE 2 cell poly (A) + RNA.