Biomedical subjects

Jamie J Van Gompel

Publications and source records attributed to Jamie J Van Gompel.

5 recordsLinked to original sources

PubMed2005

Medullary thyroid cancer: the functions of raf-1 and human achaete-scute homologue-1.

Medullary thyroid cancer (MTC) is a prototypic neuroendocrine tumor of the thyroid C cells. Other than surgery, there are no curative therapies for MTC. In this review, we detail recent studies that suggest that targeting specific signaling pathways may be a viable strategy to control MTC tumor progression. Specifically, we discuss the role of the raf-1 and achaete-scute homologue-1 pathways in the MTC tumor growth and differentiation.

Animals↗

PubMed2005

ZM336372, a Raf-1 activator, suppresses growth and neuroendocrine hormone levels in carcinoid tumor cells.

Neuroendocrine tumors, such as carcinoids, are highly metastatic neoplasms that secrete bioactive hormones resulting in carcinoid syndrome. Few curative treatments exist outside of surgical resection. We have previously shown that activation of the Raf-1 signaling pathway can suppress hormone production in carcinoid tumor cells. In this study, we investigated a novel treatment for carcinoid tumor cell growth based on pharmacologic Raf-1 activation using the compound ZM336372. Treatment of carcinoid tumor cells with ZM336372 resulted in progressive phosphorylation of Raf-1, mitogen-activated protein kinase 1/2, and extracellular signal-regulated kinase 1/2. Importantly, exposure to ZM336372 resulted in a significant reduction of bioactive hormone levels as well as the transcription factor, human achaete-scute homologue-1 in carcinoid tumor cells. Furthermore, treatment with ZM336372 led to a marked suppression of cellular proliferation and induction of the cell cycle inhibitors p21 and p18. In summary, ZM336372 targets both proliferation and palliative issues associated with carcinoid tumor cells, and therefore, warrants further investigation as a possible therapeutic strategy for patients with carcinoid tumors.

Benzamides↗

PubMed2004

Gastrointestinal carcinoid tumors: factors that predict outcome.

Gastrointestinal (GI) carcinoids are neuroendocrine tumors originating in multiple locations throughout the GI tract. The prognosis for patients with GI carcinoid tumors is diverse. To determine the factors that significantly affect prognosis, we reviewed our experience. Between 1992 and 2000 a total of 70 patients with GI carcinoid tumors underwent surgical resection at our institution. The patients were grouped into three categories based on the origin of the carcinoid tumor: foregut, midgut, hindgut. The mean age of the patients was 56 +/- 2 years. All patients with foregut carcinoids had symptoms upon presentation, whereas 61% of those with midgut carcinoids and only 37% of those with hindgut carcinoids had symptoms ( p < 0.001). The factors that most strongly affected survival on univariate analysis were a symptomatic presentation and the site of origin. Patients with foregut or midgut lesions had lower 5-year disease-free survivals than those with hindgut tumors. Moreover, the size of the primary tumor and the presence of liver metastases were not independent predictors of survival. Despite the larger tumor size and the higher incidence of liver metastases, patients with foregut carcinoids appear to have the same prognosis as those with midgut carcinoids. These data therefore suggest that the outcomes of patients with carcinoid tumors are highly dependent on the presence of symptoms and the site of origin.

Carcinoid Tumor↗

PubMed2003

Multiple determinants contribute to the virulence of HSV ocular and CNS infection and identification of serine 34 of the US1 gene as an ocular disease determinant.

PURPOSE: The virulence of any given strain of herpes simplex virus (HSV) is probably due to the effects of the constellation of genes in that strain and how they act in concert to promote disease. The goal of this work was to develop a system to identify and study the role of multiple genes in HSV disease. METHODS: Mixed ocular infection with HSV-1 strains CJ394 and OD4 yield recombinants with increased ocular and central nervous system (CNS) virulence. Clones and subclones of the CJ394 genome were cotransfected with intact OD4 DNA into Vero cells, the transfection pools were inoculated into BALB/c mouse eyes, and disease severity was scored. Fragments transferring increased ocular or CNS disease were sequenced. Site-directed mutagenesis was used to revert one mutation to wild type. RESULTS: Five of the determinants (UL9, -33, -41, and -42 and US1) increased ocular disease when transferred singly. Transfer of the UL36/37 determinant increased both ocular and CNS disease. Transfer of the UL41 and -42 genes increased mortality and a combination of the UL36/37, -41, and -42 determinants increased virulence further. Reversion of the S34A change in the OD4 US1 gene to wild type restored ocular virulence. CONCLUSIONS: Multiple HSV genes can operate to increase virulence. The UL9, -33, -36/37, and -42 genes have not previously been identified as virulence determinants. The UL41 and US1 genes are known to affect disease, but the changes identified had not been described. Multiple novel mutations were found in the OD4, UL9, UL36, and US1 genes, and we showed that S34 in the US1 gene is essential in ocular disease.

Animals↗

PubMed2002

Genome sequence and comparative microarray analysis of serotype M18 group A Streptococcus strains associated with acute rheumatic fever outbreaks.

Acute rheumatic fever (ARF), a sequelae of group A Streptococcus (GAS) infection, is the most common cause of preventable childhood heart disease worldwide. The molecular basis of ARF and the subsequent rheumatic heart disease are poorly understood. Serotype M18 GAS strains have been associated for decades with ARF outbreaks in the U.S. As a first step toward gaining new insight into ARF pathogenesis, we sequenced the genome of strain MGAS8232, a serotype M18 organism isolated from a patient with ARF. The genome is a circular chromosome of 1,895,017 bp, and it shares 1.7 Mb of closely related genetic material with strain SF370 (a sequenced serotype M1 strain). Strain MGAS8232 has 178 ORFs absent in SF370. Phages, phage-like elements, and insertion sequences are the major sources of variation between the genomes. The genomes of strain MGAS8232 and SF370 encode many of the same proven or putative virulence factors. Importantly, strain MGAS8232 has genes encoding many additional secreted proteins involved in human-GAS interactions, including streptococcal pyrogenic exotoxin A (scarlet fever toxin) and two uncharacterized pyrogenic exotoxin homologues, all phage-associated. DNA microarray analysis of 36 serotype M18 strains from diverse localities showed that most regions of variation were phages or phage-like elements. Two epidemics of ARF occurring 12 years apart in Salt Lake City, UT, were caused by serotype M18 strains that were genetically identical, or nearly so. Our analysis provides a critical foundation for accelerated research into ARF pathogenesis and a molecular framework to study the plasticity of GAS genomes.

Acute Disease↗