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The tumor suppressor p53 gene is mutated in minimally half of all cancers. It is therefore reasonable to assume that naturally occurring polymorphic genetic variants in the p53 stress response pathway might determine an individual's susceptibility to cancer. A central node in the p53 pathway is the MDM2 protein, a direct negative regulator of p53. In this(More)
The p53 protein is an important determinant in human cancer and regulates the growth of cells in culture. It is known to be a sequence-specific DNA-binding protein with a powerful activation domain, but it has not been established whether it regulates transcription directly. Here we show that intact purified wild-type human and murine p53 proteins strongly(More)
p53 is a frequent target for mutation in human tumors, and mutant p53 proteins can actively contribute to tumorigenesis. We employed a three-dimensional culture model in which nonmalignant breast epithelial cells form spheroids reminiscent of acinar structures found in vivo, whereas breast cancer cells display highly disorganized morphology. We found that(More)
The DNA from a wide variety of human tumors has sustained mutations within the conserved p53 coding regions. We have purified wild-type and tumor-derived mutant p53 proteins expressed from baculovirus vectors and examined their interactions with SV40 DNA. Using DNAase I footprinting assays, we observed that both human and murine wild-type p53 proteins bind(More)
INTRODUCTION Estrogen receptor positive breast cancers often have high levels of Mdm2. We investigated if estrogen signaling in such breast cancers occurred through an Mdm2 mediated pathway with subsequent inactivation of p53. METHODS We examined the effect of long-term 17β-estradiol (E2) treatment (five days) on the p53-Mdm2 pathway in estrogen receptor(More)
The clinically used antitumor agent mitomycin C (MC) alkylates DNA upon reductive activation, forming six covalent DNA adducts in this process. This paper focuses on differential biological effects of individual adducts in various mammalian cell cultures, observed in the authors' laboratories. Evidence is reviewed that various adducts are capable of(More)
The mitomycin derivative 10-decarbamoyl mitomycin C (DMC) more rapidly activates a p53-independent cell death pathway than mitomycin C (MC). We recently documented that an increased proportion of mitosene1-beta-adduct formation occurs in human cells treated with DMC in comparison to those treated with MC. Here, we compare the cellular and molecular response(More)
Phospholipase D (PLD) has been reported to generate survival signals that prevent apoptosis induced by serum withdrawal. We have now found that elevated expression of PLD also suppresses DNA damage-induced apoptosis. Since DNA damage-induced apoptosis is often mediated by p53, we examined the effect of elevated PLD expression on the regulation of p53(More)
Human cancers over-expressing mdm2, through a T to G variation at a single nucleotide polymorphism at position 309 (mdm2 SNP309), have functionally inactivated p53 that is not effectively degraded. They also have high expression of the alternatively spliced transcript, mdm2-C. Alternatively spliced mdm2 transcripts are expressed in many forms of human(More)
In cancer cells, the oncogenic mutant p53 (mtp53) protein is present at high levels and gain-of-function (GOF) activities with more expression of mtp53 proteins contribute to tumor growth and metastasis. Robust analytical approaches that probe the degree of metastasis of cancer cells in connection with the mtp53 activity will be extremely useful not only(More)