Design of peptidomimetics that inhibit the association of phosphatidylinositol 3-kinase with platelet-derived growth factor-beta receptor and possess cellular activity

Protein information content resides in rare peptide segments

Discovering the informational rule(s) underlying structure-function relationships in the protein language is at the core of biology. Current theories have proven inadequate to explain the origins of biological information such as that found in nucleotide and amino acid sequences. Here, we demonstrate that the information content of an amino acid motif correlates with the motif rarity. A structured analysis of the scientific literature supports the theory that rare pentapeptide words have higher significance than more common pentapeptides in biological cell 'talk'. This study expands on our previous research showing that the immunological information contained in an amino acid sequence is inversely related to the sequence frequency in the host proteome.

Akt-regulated pathways in prostate cancer

Prostate cancer remains a major cause of cancer-related mortality. Genetic clues to the molecular pathways driving the most aggressive forms of prostate cancer have been limited. Genetic inactivation of PTEN through either gene deletion or point mutation is reasonably common in metastatic prostate cancer and the resulting activation of phosphoinostide 3-kinase, AKT and mTOR provides a major therapeutic opportunity in this disease as mTOR inhibitors, HSP90 inhibitors and PI3K inhibitors begin to enter clinical development.

Disruption of protein-protein interactions: towards new targets for chemotherapy

Protein-protein interactions play a key role in various mechanisms of cellular growth and differentiation, and in the replication of pathogen organisms in host cells. Thus, inhibition of these interactions is a promising novel approach for rational drug design against a wide number of cellular and microbial targets. In the past few years, attempts to inhibit protein-protein interactions using antibodies, peptides, and synthetic or natural small molecules have met with varying degrees of success, and these will be the focus of this review.

The emerging role of the PI3-K-Akt pathway in prostate cancer progression

The PI3-K-Akt pathway plays a central role in the development and progression of prostate cancer and other malignancies. We review original studies and summarize relevant sections of previous reviews concerning the relationships between abnormalities in the PI3-K-Akt pathway and prostate cancer progression. We discuss laboratory and clinical data that indicate gene perturbation and dysregulation of PI3-K-Akt pathway is common in prostate cancer and other malignancies. We further discuss the critical role of the PI3-K-Akt pathway in the oncogenic signaling network and provide examples that establish the PI3-K-Akt pathway as a focal point for the future development of informative biomarkers and effective therapies for prostate cancer.

Protein-protein interactions: mechanisms and modification by drugs

Protein-protein interactions form the proteinaceous network, which plays a central role in numerous processes in the cell. This review highlights the main structures, properties of contact surfaces, and forces involved in protein-protein interactions. The properties of protein contact surfaces depend on their functions. The characteristics of contact surfaces of short-lived protein complexes share some similarities with the active sites of enzymes. The contact surfaces of permanent complexes resemble domain contacts or the protein core. It is reasonable to consider protein-protein complex formation as a continuation of protein folding. The contact surfaces of the protein complexes have unique structure and properties, so they represent prospective targets for a new generation of drugs. During the last decade, numerous investigations have been undertaken to find or design small molecules that block protein dimerization or protein(peptide)-receptor interaction, or on the other hand, induce protein dimerization.

Development of peptide antagonists that target estrogen receptor-cofactor interactions

We have developed a series of high-affinity peptide antagonists that inhibit the transcriptional activity of both subtypes of the human estrogen receptor (ERalpha and ERbeta). We believe that it will be possible to develop these peptides, or corresponding peptidomimetic derivatives, into pharmaceuticals for use in the treatment of breast cancer and other estrogenopathies. It is anticipated that drugs of this type could be used in combination with classical antiestrogens, such as tamoxifen, to achieve a complete blockage of ER-transcriptional activity. Although ER has been the primary target of our studies to date, it is likely that the insights gained from this work will apply to other nuclear receptors and transcription factors.

Structure-based design and synthesis of phosphinate isosteres of phosphotyrosine for incorporation in Grb2-SH2 domain inhibitors. Part 1

Based on X-ray crystal structure information, mono charged phosphinate isosteres of phosphotyrosine have been designed and incorporated in a short inhibitory peptide sequence of the Grb2-SH2 domain. The resulting compounds, by exploiting additional interactions, inhibit binding to the Grb2-SH2 domain as potently as the corresponding doubly charged (phosphonomethyl)phenylalanine analogue.