Voltage-gated Na+ channels confer invasive properties on human prostate cancer cells

Prostate cancer is the second leading cause of cancer deaths in American males, resulting in an estimated 37,000 deaths annually, typically the result of metastatic disease. A consequence of the unsuccessful androgen ablation therapy used initially to treat metastatic disease is the emergence of androgen-insensitive prostate cancer, for which there is currently no prescribed therapy. Here, three related human prostate cancer cell lines that serve as a model for this dominant form of prostate cancer metastasis were studied to determine the correlation between voltage-gated sodium channel expression/function and prostate cancer metastatic (invasive) potential: the non-metastatic, androgen-dependent LNCaP LC cell line and two increasingly tumorogenic, androgen-independent daughter cell lines, C4 and C4-2. Fluorometric in vitro invasion assays indicated that C4 and C4-2 cells are more invasive than LC cells. Immunoblot analysis showed that voltage-gated sodium channel expression increases with the invasive potential of the cell line, and this increased invasive potential can be blocked by treatment with the specific voltage-gated sodium channel inhibitor, tetrodotoxin (TTX). These data indicate that increased voltage-gated sodium channel expression and function are necessary for the increased invasive potential of these human prostate cancer cells. When the human adult skeletal muscle sodium channel Na_v1.4 was expressed transiently in each cell line, there was a highly significant increase in the numbers of invading LC, C4, and C4-2 cells. This increased invasive potential was reduced to control levels by treatment with TTX. These data are the first to indicate that the expression of voltage-gated sodium channels alone is sufficient to increase the invasive potential of non-metastatic (LC cells) as well as more aggressive cells (i.e., C4 and C4-2 cells). Together, the data suggest that increased voltage-gated sodium channel expression alone is necessary and sufficient to increase the invasive potential of a set of human prostate cancer cell lines that serve as a model for prostate cancer metastasis.     

Analysis of physical parameters associated with the measurement of high-energy x-ray penumbra

The effect of dosemeter type and configuration on the measured penumbral distribution for Co-60, 6-MV, and 31-MV x rays has been determined in air using equilibrium buildup caps for three commercial detection systems including a silicon diode and two ionization chambers. The diode is shown to be measuring a different parameter in the penumbral region than the ionization chambers. This fact in combination with the lateral spread of the secondary electrons and the difference in the inside diameters of the ionization chambers results in significant differences between the measured beam penumbra. The latter effect is studied in more detail with a series of specially designed ionization chambers of varying inside diameter from 0.3 to 1.4 cm. A theoretical model is described which resolves these differences, indicates a method to determine the true penumbral primary-dose distribution and introduces the concept of an effective diameter for the ionometric measurement of high-energy x-ray penumbra. Recommendations are made concerning the dosemeters of choice for penumbral measurements over this range of photon energies.     

Comparison of Sequences of RNAs 3 and 4 of Rice Stripe Virus from China with those of Japanese Isolates

The sequences were determined of RNAs 3 and 4 of a Chinese isolate (Y) of rice stripe tenuivirus (RStV) and were compared with those of two RStV isolates (M and T) from Japan. Both RNAs of the Y isolate were longer than those of the M and T isolates. There was almost complete conservation in the 5′ and 3′ non-coding regions for each RNA between the isolates. The analogous ambisense coding regions for each isolate were exactly the same size and the sequences were highly conserved. The major differences were in the intergenic regions, the sizes of which accounted for the differences in size of each RNA of the three isolates. There were no obvious patterns of differences in comparisons of the two RNA over the three isolates. The significance of the similarities and differences in sequences of isolates of RStV separated by more than 3500 km is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antibody responses in recipients of varicella vaccine assayed by immunoblotting

Sera taken from 35 children with cancer who had been vaccinated with live varicella vaccine were assayed using immunoblotting for the presence of IgG class antibodies to proteins present in varicella-zoster virus (VZV)-infected cells. Sera from 23 of these patients were also assayed for IgM class antibodies. The patterns of immunoreactivity observed for these patients following vaccination were substantially weaker and more variable than those detected following natural VZV infection in otherwise healthy individuals. The IgG responses detected following vaccination involved up to 10 protein bands between 28 and 188 kDa. Bands were particularly frequent in the 78–96 kDa region. IgM responses involved up to 10 bands between 28 and 114 kDa, with the bands in the 78–96 kDa region and at 32–36 kDa being detected most frequently. Repeated vaccination generally produced a stronger IgG antibody response than did single vaccination, and subsequent exposure of vaccinees to natural VZV infection resulted in an increased level of reactivity for IgG antibodies, but not for IgM. Similar reaction patterns were obtained with sera from vaccinees when the vaccine virus and wild-type VZV were used as antigens. Immunoblotting showed good correlation with indirect radioimmunoassay for the detection of a vaccine-induced IgG response.     

Two novel mutations and coexistence of the 991C.T and the 1339C.T mutation on a single allele in the coproporphyrinogen oxidase gene in Swedish patients with hereditary coproporphyria

 Hereditary coproporphyria (HCP) is an autosomal dominant disorder, resulting from a partial deficiency of the enzyme coproporphyrinogen oxidase (CPO). This enzyme catalyzes the sixth step of the heme biosynthetic pathway, and mutations in the CPO gene have been coupled to HCP. The present study was undertaken to identify disease-producing mutations in the CPO gene in nine Swedish families with HCP. Exon 1 of the CPO gene of the nine probands was analyzed directly by sequencing, and exons 2–7 were screened by denaturating gradient gel electrophoresis, followed by sequencing of exons showing abnormal band pattern. Mutations were detected in five of the nine families. In two of these families, the novel mutations 623C>T (S208F, exon 2) and 982C>T (R328C, exon 5) were identified, respectively. In the affected members of the other three families, the previously reported mutations 991C>T (R331W, exon 5) and 1339C>T (R447C, exon 7) were shown to coexist on one allele. The present study contributes 2 novel mutations to the 34 that have been previously reported to cause HCP. In addition, this is the first report on patients carrying two HCP-coupled mutations on one allele. Received: March 8, 2002 / Accepted: April 24, 2002     

Analysis of mutations at the neurofibromatosis 1 (NF1) locus.

A panel of 200 unrelated NF1 individuals has been screened for mutations using a panel of specific clones for the entire gene. DNA analysis on conventional Southern blots indicated that (20) 10% of NF1 patients showed aberrant bands. Small lesions involving nucleotide alterations were detected in a further 10 patients; 5 of these alterations have been fully characterised and are the novel mutations in the NF1 gene. A number of mutations were identified in exon 2. Identical mutations in this exon in two unrelated individuals involved an insertion of cytosine into codon 5662 and resulted in an inappropriate stop codon. This mutation also created a new MnlI site. Another novel mutation in exon 2 resulted from the insertion of thymidine at nucleotide 5678, which also created an inappropriate stop codon. We have so far completed the screen of exons 1-9 of the NF1 gene for the identification of mutations and have found no evidence of clustering of such mutations in the gene.