Paul G. Richardson

Bio: Paul G. Richardson is an academic researcher from Harvard University. The author has contributed to research in topics: Multiple myeloma & Bortezomib. The author has an hindex of 183, co-authored 1533 publications receiving 155912 citations. Previous affiliations of Paul G. Richardson include Broomfield Hospital & Dartmouth College.

Interactions of the Hdm2/p53 and Proteasome Pathways May Enhance the Antitumor Activity of Bortezomib

Abstract: Purpose: p53 is inactivated in many human malignancies through missense mutations or overexpression of the human homologue of Mdm2 (Hdm2), an E3 ubiquitin ligase that ubiquitinates p53, thereby promoting its proteasomal degradation. The cis -imidazoline nutlin-3 can disrupt the p53-Hdm2 interaction and activate p53, inducing apoptosis in vitro in many malignancies, including multiple myeloma (MM). Experimental Design: We hypothesized that suppression of Hdm2-mediated p53 ubiquitination may augment sequelae of p53 accumulation caused by proteasomal inhibition. We compared the response of MM cells versus several epithelial cancer models to the proteasome inhibitor bortezomib in combination with nutlin-3. Results: The combination of sublethal concentrations of bortezomib plus nutlin-3 induced additive cytotoxicity against bortezomib-sensitive MM cell lines. Importantly, however, in breast, prostate, colon, and thyroid (papillary, follicular, anaplastic, and medullary) carcinoma cell lines, this combination triggered synergistic cytotoxicity, and increased expression of p53, p21, Hdm2, Bax, Noxa, PUMA, and cleavage of caspase-3 and poly ADP ribose polymerase. Coculture with bone marrow stromal cells attenuated MM cell sensitivity to nutlin-3 monotherapy and was associated with evidence of suppression of p53 activity in MM cells, whereas combined bortezomib-nutlin-3 treatment maintained cytotoxicity even in the presence of bone marrow stromal cells. Conclusions: This differential response of MM versus epithelial carcinomas to combination of nutlin-3 with bortezomib sheds new light on the role of p53 in bortezomib-induced apoptosis. Concurrent Hdm2 inhibition with bortezomib may extend the spectrum of bortezomib applications to malignancies with currently limited sensitivity to single-agent bortezomib or, in the future, to MM patients with decreased clinical responsiveness to bortezomib-based therapy. (Clin Cancer Res 2009;15(23):7153–60)

Tanespimycin monotherapy in relapsed multiple myeloma: results of a phase 1 dose-escalation study.

Abstract: Heat shock protein 90 (HSP90), one of a family of molecular chaperones, is intimately involved in the survival of tumour cells. Under normal conditions, HSP90 prevents aggregation of proteins and functions as a chaperone that preserves the 3-dimensional conformation, intracellular localization, and activity and regulates the proteolytic turnover of a range of proteins. Under conditions of stress, the expression of HSP90 increases as an adaptive response intended to enhance cell survival. This basic function also contributes to tumour cell proliferation, thereby driving oncogenesis. (Whitesell & Lindquist, 2005; Powers & Workman, 2006). HSP90 is uniformly expressed in a variety of human multiple myeloma (MM) cell lines and primary specimens from patients with MM. (Mitsiades et al, 2002, 2006) It has been shown to be critical to the survival of MM cell lines grown in culture. (Chatterjee et al, 2007) Investigators have also demonstrated that HSP90 inhibitors suppress the expression of client proteins including insulin-like growth factor-1 receptor (IGF-1R) and interleukin 6 receptor (IL-6R), which in turn disrupts interactions between bone marrow stromal cells and MM tumour cells,(Mitsiades et al, 2006) as well as upregulating other HSPs including HSP70. Upregulation of HSP70 is a marker of HSP90 inhibition, and multiple phase 1 clinical trials evaluating HSP90 inhibitors have shown a correlative increase in HSP70 in the presence of HSP90 inhibition. (Banerji et al, 2005; Goetz et al, 2005; Grem et al, 2005). Tanespimycin (17-allylamino-17-demethoxygeldanamycin, 17-AAG) is a synthetic geldanamycin analogue and was the first HSP90 inhibitor to enter clinical trials(Sausville et al, 2003) in patients with advanced malignancies. (Banerji et al, 2005; Goetz et al, 2005; Grem et al, 2005; Ramanathan et al, 2007) Studies have evaluated several dosing schedules in this patient population to identify a maximum tolerated dose (MTD). (Banerji et al, 2005; Goetz et al, 2005; Grem et al, 2005; Nowakowski et al, 2006; Solit et al, 2007) One trial infused tanespimycin on days 1, 8, and 15 of a 28-day cycle(Goetz et al, 2005); another chose a daily dosing schedule of 5 d every 3 weeks(Grem et al, 2005); and a third used a once weekly regimen. (Banerji et al, 2005) These dosing schedules were generally well tolerated and produced antitumour activity in various solid tumour types. As part of in vitro studies, tanespimycin was shown to potently induce apoptosis of both drug-sensitive and drug-resistant MM cell lines, as well as tumour cells from patients with relapsed/refractory MM. (Mitsiades et al, 2006) Tanespimycin was also shown to suppress cell surface expression of receptors for cytokines mediating MM cell growth, survival, drug resistance, and related downstream signalling pathways among other pleiotropic antiproliferative and proapoptotic molecular sequelae, allowing tanespimycin to sensitize MM cells to other anticancer agents. (Mitsiades et al, 2006). Based on the preclinical rationale and safety profile demonstrated in phase 1 trials, the primary study objective was to evaluate the MTD of tanespimycin given in a twice weekly dosing schedule (day 1, 4, 8, and 11 of each 21-day cycle), for up to 8 cycles of treatment in patients with relapsed and refractory MM. Secondary objectives were to measure plasma pharmacokinetics (PK) of tanespimycin in the study population, evaluate the safety of repeated tanespimycin doses, and assess any preliminary evidence of antitumour activity following treatment. Results showed both anti-disease activity and favorable tolerability, establishing the framework for subsequent clinical exploration as monotherapy and as part of combination regimens.

Phase transitions in human IgG solutions

Abstract: Protein condensations, such as crystallization, liquid-liquid phase separation, aggregation, and gelation, have been observed in concentrated antibody solutions under various solution conditions. While most IgG antibodies are quite soluble, a few outliers can undergo condensation under physiological conditions. Condensation of IgGs can cause serious consequences in some human diseases and in biopharmaceutical formulations. The phase transitions underlying protein condensations in concentrated IgG solutions is also of fundamental interest for the understanding of the phase behavior of non-spherical protein molecules. Due to the high solubility of generic IgGs, the phase behavior of IgG solutions has not yet been well studied. In this work, we present an experimental approach to study IgG solutions in which the phase transitions are hidden below the freezing point of the solution. Using this method, we have investigated liquid-liquid phase separation of six human myeloma IgGs and two recombinant pharmaceutical human IgGs. We have also studied the relation between crystallization and liquid-liquid phase separation of two human cryoglobulin IgGs. Our experimental results reveal several important features of the generic phase behavior of IgG solutions: (1) the shape of the coexistence curve is similar for all IgGs but quite different from that of quasi-spherical proteins; (2) all IgGs have critical points located at roughly the same protein concentration at ∼100 mg/ml while their critical temperatures vary significantly; and (3) the liquid-liquid phase separation in IgG solutions is metastable with respect to crystallization. These features of phase behavior of IgG solutions reflect the fact that all IgGs have nearly identical molecular geometry but quite diverse net inter-protein interaction energies. This work provides a foundation for further experimental and theoretical studies of the phase behavior of generic IgGs as well as outliers with large propensity to condense. The investigation of the phase diagram of IgG solutions is of great importance for the understanding of immunoglobulin deposition diseases as well as for the understanding of the colloidal stability of IgG pharmaceutical formulations.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The Pfam protein families database

Abstract: Pfam is a widely used database of protein families and domains. This article describes a set of major updates that we have implemented in the latest release (version 24.0). The most important change is that we now use HMMER3, the latest version of the popular profile hidden Markov model package. This software is approximately 100 times faster than HMMER2 and is more sensitive due to the routine use of the forward algorithm. The move to HMMER3 has necessitated numerous changes to Pfam that are described in detail. Pfam release 24.0 contains 11,912 families, of which a large number have been significantly updated during the past two years. Pfam is available via servers in the UK (http://pfam.sanger.ac.uk/), the USA (http://pfam.janelia.org/) and Sweden (http://pfam.sbc.su.se/).

The sequence of the human genome.

Abstract: A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

The Human Genome Browser at UCSC

Abstract: As vertebrate genome sequences near completion and research refocuses to their analysis, the issue of effective genome annotation display becomes critical. A mature web tool for rapid and reliable display of any requested portion of the genome at any scale, together with several dozen aligned annotation tracks, is provided at http://genome.ucsc.edu. This browser displays assembly contigs and gaps, mRNA and expressed sequence tag alignments, multiple gene predictions, cross-species homologies, single nucleotide polymorphisms, sequence-tagged sites, radiation hybrid data, transposon repeats, and more as a stack of coregistered tracks. Text and sequence-based searches provide quick and precise access to any region of specific interest. Secondary links from individual features lead to sequence details and supplementary off-site databases. One-half of the annotation tracks are computed at the University of California, Santa Cruz from publicly available sequence data; collaborators worldwide provide the rest. Users can stably add their own custom tracks to the browser for educational or research purposes. The conceptual and technical framework of the browser, its underlying MYSQL database, and overall use are described. The web site currently serves over 50,000 pages per day to over 3000 different users.