Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have identified a novel gap junction gene by searching the human genome sequence database that encodes a protein designated as connexin31.9 (Cx31.9). Cx31.9 was most homologous to human Cx32.4 and did not cluster with either the purported alpha- or beta-connexin subfamilies. Expression of Cx31.9 was detected by RT-PCR in human mRNA from several tissues including cerebral cortex, heart, liver, lung, kidney, spleen, and testis. A partial Cx31.9 sequence was also represented in the human Expressed Sequence Tag database. Cx31.9 formed intercellular channels in both paired Xenopus oocytes and transfected neuroblastoma N2A cells that were distinguished by an apparent low unitary conductance (12-15 pS) and a remarkable insensitivity to transjunctional voltage. In contrast, Cx31.9 channels were gated by cytoplasmic acidification or exposure to halothane like other connexins. Cx31.9 was able to form heterotypic channels with the highly voltage-sensitive Xenopus Cx38 (XenCx38), which provides an opportunity to study gating in heterotypic channels formed by hemichannels (connexons) composed of connexins with widely divergent properties. Thus Cx31.9 is a novel human connexin that forms channels with unique functional properties.
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PMID:Virtual cloning, functional expression, and gating analysis of human connexin31.9. 1217 52

Neuroblastoma is the most common extracranial solid tumor in childhood. The poor outcomes of patients with high-risk neuroblastoma have encouraged the search for new therapies. In the current study, the effect of the vitamin D analog 1alpha-hydroxyvitamin D2 (1alpha-OH-D2, doxercalciferol) was assessed in a mouse xenograft model of human neuroblastoma. Vitamin D receptor (VDR) expression levels in seven neuroblastoma cell lines were compared using real-time PCR. SK-N-AS cells, which express relatively high levels of VDR, were injected into the flanks of 60 mice. The mice were treated daily via oral gavage for 5 weeks with vehicle (control), 0.15 microg, or 0.3 microg of 1alpha-OH-D2. The animals were then euthanized, and tumors, sera, and kidneys were collected and analyzed. End tumor volumes were significantly smaller in both the 0.15 microg group (712.07 mm3, P = 0.0121) and 0.3 microg group (772.97 mm3, P = 0.0209) when compared to controls (1,681.75 mm3). In terms of toxicity, serum calcium levels were increased but mortality was minimal in both treatment groups. These results were similar to those previously described in the transgenic (LHbeta-Tag) and human xenograft (Y-79) models of retinoblastoma, a related tumor. In vitro cell viability studies of SK-N-AS and NGP cells, which represent two major human neuroblastoma subtypes that differ in their genetic abnormalities as well as their VDR expression levels, show that both are sensitive to calcitriol, the active metabolite of vitamin D3. In conclusion, the present study shows that 1alpha-OH-D2 can inhibit human neuroblastoma growth in vivo with relatively low toxicity. The safety of 1alpha-OH-D2 has been extensively studied; the drug is FDA-approved for the treatment of adult kidney patients, and Phase I/II trials have been conducted in adult oncology patients. There should not be major obstacles to starting Phase I and II clinical trials with this drug in pediatric patients with high-risk neuroblastoma.
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PMID:1 alpha-Hydroxyvitamin D2 inhibits growth of human neuroblastoma. 1760 51