Mapping molecular networks using proteomics: a vision for patient-tailored combination therapy.

Mapping tumor cell protein networks in vivo will be critical for realizing the promise of patient-tailored molecular therapy. Cancer can be defined as a dysregulation or hyperactivity in the network of intracellular and extracellular signaling cascades. These protein signaling circuits are the ultimate targets of molecular therapy. Each patient's tumor may be driven by a distinct series of molecular pathogenic defects. Thus, for any single molecular targeted therapy, only a subset of cancer patients may respond. Individualization of therapy, which tailors a therapeutic regimen to a tumor molecular portrait, may be the solution to this dilemma. Until recently, the field lacked the technology for molecular profiling at the genomic and proteomic level. Emerging proteomic technology, used concomitantly with genomic analysis, promises to meet this need and bring to reality the clinical adoption of molecular stratification. The activation state of kinase-driven signal networks contains important information relative to cancer pathogenesis and therapeutic target selection. Proteomic technology offers a means to quantify the state of kinase pathways, and provides post-translational phosphorylation data not obtainable by gene arrays. Case studies using clinical research specimens are provided to show the feasibility of generating the critical information needed to individualize therapy. Such technology can reveal potential new pathway interconnections, including differences between primary and metastatic lesions. We provide a vision for individualized combinatorial therapy based on proteomic mapping of phosphorylation end points in clinical tissue material.     

The selective serotonin-2A receptor antagonist M100907 reverses behavioral deficits in dopamine transporter knockout mice.

A hyperdopaminergic state in humans has been hypothesized to contribute to the pathology of a number of psychiatric illnesses, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. Mice that display elevated synaptic levels of dopamine due to a genetically engineered deletion of the dopamine transporter (DAT) model behavioral deficits that simulate the above conditions. As novel treatment strategies for these disorders have focused on the serotonin (5-HT) 2A receptor, we determined the capacity of the highly selective 5-HT(2A) receptor antagonist M100907 to reverse behavioral deficits in DAT knockout (KO) mice. Prior to drug treatment, DAT KO mice exhibited increased levels of locomotor activity and highly linearized movement in a novel environment, as well as reduced prepulse inhibition (PPI) of acoustic startle, compared to wild-type littermates. Treatment with M100907 (0.3-1.0 mg/kg, but not 0.1 mg/kg) reversed locomotor deficits in DAT KO mice. Similarly, treatment with 1.0 mg/kg M100907 reversed the PPI deficits in DAT KO mice. These data indicate that selective 5-HT(2A) receptor antagonists, such as M100907, may represent a class of drugs that can be used to treat conditions in which a chronic, elevated dopaminergic tone is present and contributes to abnormal behavior and sensorimotor gating deficits.     

Molecular cloning of the guinea pig CYP1A2 gene 5'-flanking region: identification of functional aromatic hydrocarbon response element and characterization of CYP1A2 expression in GPC16 cells.

Aromatic hydrocarbon (AH) effects are mediated by binding of the AH receptor and its heterodimeric partner aromatic hydrocarbon nuclear translocator to specific response elements on DNA (AHREs). CYP1A2 expression is induced by AHs, yet AHREs have been identified in CYP1A2 genes of only two species and their functional role assessed only in the human gene. There have been few analyses of CYP1A2 gene regulation in nonhepatic cells. To gain further insight into CYP1A2 regulation, we cloned the initial 1.2 kilobases (kb) of the guinea pig CYP1A2 gene 5'-flanking region and characterized CYP1A2 expression in guinea pig colon adenocarcinoma cells (GPC16). Two putative AHRE sites were identified (-830 and -575 bp). They are considerably more proximal than the functional AHRE found in the human CYP1A2 gene (-2.5 kb). GPC16 cells expressed CYP1A2 after treatment with AH, enabling characterization of the putative AHRE sites in a homologous cell line. Double-stranded oligonucleotide probes, corresponding to each putative AHRE, bound in an AH-induced and specific manner to nuclear proteins prepared from GPC16 cells. In transfection analyses, only the distal site mediated AH-induced reporter gene activity. Mutation of this site suppressed AH-induced activity, supporting the concept that it is involved in AH-mediated induction of CYP1A2. However, the low level of AH-induction by the wild type suggests that other factors modulate AH-response by the CYP1A2 gene.     

Functional interplay between the ATP binding cassette Msr(D) protein and the membrane facilitator superfamily Mef(E) transporter for macrolide resistance in Escherichia coli

Macrolides have wide clinical applications in the treatment of community-acquired respiratory tract infections, among which streptococci are the most frequent causative agents. An active efflux-based mechanism of macrolide resistance, referred to as the M phenotype in streptococcal isolates, has been associated with the presence of mef genes that encode a subset of major facilitator superfamily (MFS) transporters like Mef(E). An msr(D) gene, adjacent to and co-transcribed with mef in the presence of erythromycin, has also been implicated in drug efflux, but its role remains elusive. Msr(D) belongs to the ATP binding cassette (ABC) proteins and harbors two fused nucleotide-binding domains with no membrane-spanning domains. The present work indicates that the major resistance traits of the M phenotype in Escherichia coli may be due to Msr(D) and not to Mef(E). Fluorescence microscopy using Mef(E) tagged with GFP linked low efficacy of the chimera in conferring macrolide resistance with improper subcellular localization. The active role of Msr(D) in directing Mef(E)-GFP to the cell poles was demonstrated, as was synergistic effect in terms of levels of resistance when both proteins were expressed. A trans-dominant negative mutation within ABC Msr(D) affecting MFS Mef(E) strongly suggests that both proteins can interact in vivo, and such a physical interaction was supported in vitro. This is the first reported example of a functional interplay between an ABC component and an MFS transporter. The direct involvement of Msr(D) in the efflux of macrolides remains to be demonstrated.     

Coexistence of benign phyllodes tumor and invasive ductal carcinoma in distinct breasts: case report

This report describes a rare case of coexistence of benign phyllodes tumor, which measured 9 cm in the right breast, and invasive ductal carcinoma of 6 cm in the left breast, synchronous and independent, in a 66-year-old patient. The patient underwent a bilateral mastectomy due to the size of both lesions. Such situations are rare and usually refer to the occurrence of ductal or lobular carcinoma in situ when associated with malignant phyllodes tumors, and more often in ipsilateral breast or intra-lesional.