ABSTRACT
Clinical observations suggest that pregnancy provides protection against cancer. The mechanisms involved, however, remain unclear. Fetal cells are known to enter the mother's circulation during pregnancy and establish microchimerism. We investigated if pregnancy-related embryonic/fetal stem cell integration plays a role in breast cancer. A high-sensitivity Y-chromosome assay was developed to trace male allogeneic cells (from male fetus) in females. Fixed-embedded samples (n = 206) from both normal and breast cancer patients were screened for microchimerism. The results were combined with matching clinicopathological and histological parameters and processed statistically. The results show that in our samples (182 informative) more than half of healthy women (56%) carried male cells in their breast tissue for decades (n = 68), while only one out of five in the cancer sample pool (21%) (n = 114) (odds ratio = 4.75, CI at 95% 2.34-9.69; p = 0.0001). The data support the notion that a biological link may exist between chimerism and tissue-integrity. The correlation, however, is non-linear, since male microchimerism in excess ("hyperchimerism") is also involved in cancer. The data suggest a link between hyperchimerism and HER2-type cancers, while decreased chimerism ("hypochimerism") associates with ER/PR-positive (luminal-type) breast cancers. Chimerism levels that correlate with protection appear to be non-random and share densities with the mammary progenitor components of the stem cell lineage in the breast. The results suggest that protection may involve stem/progenitor level interactions and implicate novel quantitative mechanisms in chimerism biology.
Subject(s)
Breast Neoplasms/genetics , Breast/metabolism , Chimerism , Base Sequence , Chromosomes, Human, Y , DNA/genetics , DNA Primers , Female , Genes, erbB-2 , Humans , Male , Polymerase Chain ReactionABSTRACT
To identify molecular mechanisms that function in G-protein signaling, we have performed molecular genetic studies of a simple behavior of the nematode Caenorhabditis elegans, egg laying, which is driven by a pair of serotonergic neurons, the hermaphrodite-specific neurons (HSNs). The activity of the HSNs is regulated by the G(o)-coupled receptor EGL-6, which mediates inhibition of the HSNs by neuropeptides. We report here that this inhibition requires one of three inwardly rectifying K(+) channels encoded by the C. elegans genome: IRK-1. Using ChannelRhodopsin-2-mediated stimulation of HSNs, we observed roles for egl-6 and irk-1 in regulating the excitability of HSNs. Although irk-1 is required for inhibition of HSNs by EGL-6 signaling, we found that other G(o) signaling pathways that inhibit HSNs involve irk-1 little or not at all. These findings suggest that the neuropeptide receptor EGL-6 regulates the potassium channel IRK-1 via a dedicated pool of G(o) not involved in other G(o)-mediated signaling. We conclude that G-protein-coupled receptors that signal through the same G-protein in the same cell might activate distinct effectors and that specific coupling of a G-protein-coupled receptor to its effectors can be determined by factors other than its associated G-proteins.
Subject(s)
Caenorhabditis elegans/physiology , GTP-Binding Protein alpha Subunits, Gi-Go/physiology , Neuropeptides/pharmacology , Potassium Channels, Inwardly Rectifying/physiology , Serotonergic Neurons/physiology , Alleles , Amino Acid Sequence , Animals , Animals, Genetically Modified , Behavior, Animal/physiology , Genome , Ion Channel Gating/physiology , Molecular Sequence Data , Oocytes , Polymerase Chain Reaction , Potassium Channels, Inwardly Rectifying/genetics , Sexual Behavior, Animal/physiology , Signal Transduction/physiology , Xenopus laevisABSTRACT
Many animals possess neurons specialized for the detection of carbon dioxide (CO(2)), which acts as a cue to elicit behavioral responses and is also an internally generated product of respiration that regulates animal physiology. In many organisms how such neurons detect CO(2) is poorly understood. We report here a mechanism that endows C. elegans neurons with the ability to detect CO(2). The ETS-5 transcription factor is necessary for the specification of CO(2)-sensing BAG neurons. Expression of a single ETS-5 target gene, gcy-9, which encodes a receptor-type guanylate cyclase, is sufficient to bypass a requirement for ets-5 in CO(2)-detection and transforms neurons into CO(2)-sensing neurons. Because ETS-5 and GCY-9 are members of gene families that are conserved between nematodes and vertebrates, a similar mechanism might act in the specification of CO(2)-sensing neurons in other phyla.
Subject(s)
Caenorhabditis elegans Proteins/physiology , Carbon Dioxide/chemistry , Gene Expression Regulation , Guanylate Cyclase/metabolism , Proto-Oncogene Proteins c-ets/metabolism , Receptors, Guanylate Cyclase-Coupled/physiology , Sensory Receptor Cells/metabolism , Alleles , Animals , Behavior, Animal , Binding Sites , Caenorhabditis elegans , Caenorhabditis elegans Proteins/genetics , Carbon Dioxide/metabolism , Gene Deletion , Microscopy, Fluorescence/methods , Mutation , Neurons/metabolism , Plasmids/metabolism , Proto-Oncogene Proteins c-ets/genetics , Proto-Oncogene Proteins c-ets/physiology , Receptors, Guanylate Cyclase-Coupled/geneticsABSTRACT
We evaluated the combination of thalidomide, pulsed dexamethasone and weekly cyclophosphamide (CTD) for the treatment of patients with newly diagnosed, relapsed or VAD-refractory multiple myeloma. We found that this combination was highly effective in inducing responses in all treatment groups with an overall response rate of 83.8%. CTD was well tolerated and did not impair stem cell mobilization.
