Genetic analysis of Raf1, Mdm2, c-Myc, Cdc25a and Cdc25b proto-oncogenes in 2′,3′-dideoxycytidine- and 1,3-butadiene-induced lymphomas in B6C3F1 mice
ABSTRACT We have previously identified activation of ras proto-oncogenes and inactivation of tumor suppressor genes including p53, p16INK4a and p15INK4b in 2′,3′-dideoxycytidine (ddC)- and/or 1,3-butadiene (BD)-induced lymphomas derived from B6C3F1 (C57BL/6xC3H/He) mice, indicating that alterations of ras signaling pathway, p53 and pRb growth control pathways are important in the development of these chemically induced lymphomas. However, there is still a subset of tumors that displayed no changes in these genes. Thus, we investigated whether the Raf1, Mdm2, c-Myc, Cdc25a and Cdc25b proto-oncogenes, which are implicated in the ras or p53 or pRb pathways, are alternative oncogenic target genes. Analyses of gross genomic alterations by Southern blots failed to reveal rearrangement or amplification in any of the tumors examined. Frequent point mutations on the substrate binding domain of the Raf1 gene has been reported in 1-ethyl-1-nitrosourea (ENU)-induced murine lymphomas and lung tumors, along with a conspicuous lack of ras mutations [U. Naumann, I. Eisenmann-Tappe, U.R. Rapp, The role of raf kinases in development and growth of tumors, Recent Results Cancer Res., 143 (1997) 237–244]. To investigate whether Raf1 mutation is involved in our set of tumor especially those without ras mutations, the PCR-based single-strand conformation analyses (SSCA) and direct DNA sequencing were employed. No mutations but four genetic polymorphisms between C57BL/6 and C3H/He were found, with two of them reported as point mutations previously (op. cit.). The polymorphisms were utilized for allelic loss study of Raf1 locus. Losses of heterozygosity were found in six of 31 BD-induced lymphomas. These results indicate that genetic alterations of c-Myc, Cdc25, Raf1 and Mdm2 proto-oncogenes may not be involved in the development of ddC- and BD-induced lymphomas and the inactivation of tumor suppressor gene(s) located close to Raf1 gene might be important in the development of a subset of BD-induced lymphomas.
[Show abstract] [Hide abstract]
ABSTRACT: HIV infection is related to an increased risk of cancer compared with general population, both AIDS-defining cancers (Kaposi's sarcoma, non Hodgkin's lymphoma, invasive cervical cancer) and non-AIDS-defining cancers. Although the advent of the highly active antiretroviral therapy era has decreased the Kaposi's sarcoma and non-Hodgkin's lymphoma incidences, non-AIDS-defining malignancies, such as lung cancer, hepatocarcinoma, anal cancer and skin cancers, remain a major cause of morbidity and death in the HIV-infected population. The clinical presentation is often different between the infected and non-infected populations, often with a more advanced stage at diagnosis, a more aggressive pathology, and associated morbidities like immunosuppression, leading to poorer outcomes. Numerous studies have focused on HIV-related malignancies' treatment, however specific guidelines are still missing. Practitioners have to be careful with interactions between antiretroviral and antineoplastic drugs, particularly through the cytochrome P 450. Because of this, a national multidisciplinary approach, "Cancer and HIV, " was started in 2013 thanks to the National Institute of Cancer (INCa). The aim of this review is to present a scientific update about AIDS-and non-AIDS-defining malignancies, both in their clinical aspects and regarding their specific therapeutic management.Bulletin du cancer 11/2014; 101(11):1020-1029. DOI:10.1684/bdc.2014.2032 · 0.64 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: 1,3-Butadiene (BD) is a multisite carcinogen in laboratory rodents following lifetime exposure, with greater potency in the mouse than the rat, and is associated with an increase in leukemia mortality in highly exposed workers. Species differences in the formation of reactive metabolites underlie observed species differences in sensitivity to the carcinogenic effects of BD. The modes of action (MOAs) for human leukemia and rodent tumors are both likely related to mutagenic potencies of one or more of these metabolites. However, differences in the nature of genotoxic lesions associated with human leukemia and rodent tumors, along with their implications for risk assessment, require that they be discussed separately. The MOAs for BD are assessed in this review using the modified Hill criteria and human relevance framework. Key events in MOAs for human and rodent cancers are identified, along with important species differences and sources of nonlinearity for each event that can affect extrapolations made from high- to low-dose exposures. Because occupational exposures to BD have also included co-exposures to styrene and dimethyldithiocarbamide (DMDTC), potential interactions with BD carcinogenicity are also discussed. The MOAs for BD carcinogenesis will be used to guide key decisions made in the quantitative cancer dose-response assessment.Critical Reviews in Toxicology 10/2010; 40 Suppl 1(S1):74-92. DOI:10.3109/10408444.2010.507183 · 6.41 Impact Factor
Immunotechnology 01/1996; 2(4). DOI:10.1016/S1380-2933(97)89113-0