Abstract
We tested the effect of expression of the Human Papilloma Virus (HPV E7) oncogene on hematopoiesis in long-term bone marrow cultures (LTBMCs) derived from K14E7 (FVB) Fancd2−/− (129/Sv), K14E7 Fancd2+/+, Fancd2−/−, and control (FVB X 129/Sv) Fl mice. K14E7 Fancd2−/− and Fancd2−/− LTBMCs showed decreased duration of production of total nonadherent hematopoietic cells and progenitors forming day 7 and day 14 multilineage CFU-GEMM colonies in secondary cultures (7 wks and 8 wks respectively) compared to cultures from K14E7 Fancd2+/+ (17 wks) or control mice (18 wks) p < 0.0001. Marrow stromal cell lines derived from both K14E7 Fancd2−/− and Fancd2−/− cultures were radiosensitive, as were IL-3 dependent hematopoietic progenitor cell lines derived from K14E7 Fancd2−/− cultures. In contrast, Fancd2−/− mouse hematopoietic progenitor cell lines and fresh marrow were radioresistant. K14E7 Fancd2−/− mouse freshly explanted bone marrow expressed no detectable K14 or E7; however, LTBMCs produced K14 positive factor-independent (FI) clonal malignant plasmacytoma forming cell lines in which E7 was detected in the nucleus with p53 and Rb. Transfection of an E6/E7 plasmid into Fancd2−/−, but not control Fancd2+/+ IL-3 dependent hematopoietic progenitor cell lines, increased cloning efficiency, cell growth, and induced malignant cell lines. Therefore, the altered radiobiology of hematopoietic progenitor cells and malignant transformation in vitro by K14E7 expression in cells of the Fancd2−/− genotype suggests a potential role of HPV in hematopoietic malignancies in FA patients.
Highlights
Fanconi Anemia (FA) patients display a variety of inherited and acquired phenotypes [1], which are dependent upon mutation or deletion of one or more of the 18 gene products in the FA pathway [2,3]
We tested the effect of expression of the Human Papilloma Virus (HPV E7) oncogene on hematopoiesis in long-term bone marrow cultures (LTBMCs) derived from K14E7 (FVB) Fancd2−/− (129/Sv), K14E7 Fancd2+/+, Fancd2−/−, and control (FVB X 129/Sv) Fl mice
Marrow stromal cell lines derived from both K14E7 Fancd2−/− and Fancd2−/− cultures were radiosensitive, as were IL-3 dependent hematopoietic progenitor cell lines derived from K14E7 Fancd2−/− cultures
Summary
Fanconi Anemia (FA) patients display a variety of inherited and acquired phenotypes [1], which are dependent upon mutation or deletion of one or more of the 18 gene products in the FA pathway [2,3]. Fanconi Anemia (FA) patients have an increased frequency of squamous cell head and neck cancers [17,18,19,20]. The hypotheses that FA patients are more susceptible to malignant transformation of squamous cells by HPV, and that evolution of such cancers might relate to the intrinsic cellular radiosensitivity and FA pathway protein alterations, are subjects of current investigation [6, 17, 21,22,23]. HPV can alter DNA double strand break repair by homologous recombination [23], (a pathway which is already defective in FA patients [2,3]). HPV enhances TGF-β signaling [24], which may be deleterious in FA patients, who have a hyperactive response to TGF-β [25]
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