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Transforming activity of nasopharyngeal carcinoma DNA detectable in mouse JB6 cells
N H Colburn1, N Raab-Traub, D Becker
1Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, MD 21701.
Abstract:
A JB6 mouse epidermal recipient cell line has been used to detect nasopharyngeal carcinoma (NPC) DNA-associated transforming activity that is not detectable in the NIH 3T3 focus assay. NPC DNA showed both transforming activity and activity for transferring sensitivity to tumor-promoter-induced neoplastic transformation, assayed in 2 different variants of mouse JB6 cells. Comparison of DNAs from various NPC sources that did or did not harbor EBV DNA and that varied in degree of differentiation showed similar transforming activities and similar activities for transferring promotion sensitivity. Thus both a NPC DNA-associated promotion sensitivity and an oncogenic activity function independently of concurrent EBV gene expression.
Insights
Nasopharyngeal carcinoma (NPC) DNA exhibits transforming activity and enhances sensitivity to tumor promoters, independent of Epstein-Barr virus (EBV). This oncogenic activity was detected using JB6 mouse cells, not NIH 3T3 assays.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Nasopharyngeal carcinoma (NPC) is a malignancy with complex etiology.
- Detecting oncogenic activity in tumor DNA is crucial for understanding cancer development.
- The role of Epstein-Barr virus (EBV) in NPC pathogenesis is well-established, but the direct transforming activity of NPC DNA remains less understood.
Purpose of the Study:
- To investigate the transforming activity of nasopharyngeal carcinoma (NPC) DNA.
- To determine if NPC DNA confers sensitivity to tumor-promoter-induced neoplastic transformation.
- To assess the independence of these activities from Epstein-Barr virus (EBV) gene expression.
Main Methods:
- Utilized the JB6 mouse epidermal cell line, a sensitive model for detecting transforming activity.
- Assayed NPC DNA for transforming potential using two variants of JB6 cells.
- Compared DNA from various NPC sources, differing in EBV status and differentiation, to evaluate activity consistency.
Main Results:
- NPC DNA demonstrated transforming activity detectable in JB6 cells, unlike the NIH 3T3 focus assay.
- NPC DNA conferred sensitivity to tumor-promoter-induced neoplastic transformation.
- These activities were observed consistently across NPC samples regardless of EBV DNA presence or tumor differentiation.
Conclusions:
- NPC DNA possesses intrinsic oncogenic activity and modulates cellular sensitivity to tumor promoters.
- These transforming and promotion-sensitizing functions are independent of concurrent EBV gene expression in NPC.
- The JB6 cell line is a valuable tool for identifying oncogenic activities in tumor DNA.