TY - JOUR
T1 - Antagonism of Voltage-gated Calcium Channels in Small Cell Carcinomas of Patients with and without Lambert-Eaton Myasthenic Syndrome by Autoantibodies ω-Conotoxin and Adenosine
AU - De Aizpurua, Henry J.
AU - Lambert, Edward H.
AU - Griesmann, Guy E.
AU - Olivera, Baldomero M.
AU - Lennon, Vanda A.
PY - 1988/9
Y1 - 1988/9
N2 - The Lambert-Eaton myasthenic syndrome (LES) is an autoimmune presynaptic disorder of peripheral cholinergic neurotransmission in which there is often an associated small cell lung carcinoma (SCC). SCC lines established from patients with and without LES exhibit a Ca2+ influx response to depolarization by K+ that is consistent with the presence of voltage-gated Ca2+ channels. Autoantibodies antagonistic to SCC Ca2+ channel activity were found exclusively in patients with LES, independent of cancer status. Depolarization-induced uptake of 45 Ca2+ by SCC lines was reduced maximally after 3–4 days of exposure to serum immunoglobulins from 14 of 19 LES patients, while 53 control immunoglobulins (including patients with SCC, other tumors, other paraneoplastic syndromes, and other neurological and autoimmune diseases) were without effect. The snail neurotoxin ω-contoxin of subtype GVIA, which is a specific antagonist of presynaptic Ca2+ channels, inhibited K+-stimulated Ca2+ uptake in a dose-dependent manner that was essentially irreversible. Adenosine, reported to be a specific antagonist of neuronal Ca2+ channels, also impaired voltage-stimulated Ca2+ influx in SCC. Use of LES patients9 IgG and ω-conotoxin in further studies of SCC may facilitate identification and purification of the LES antigen(s) and yield a quantitative serological test for diagnosing this autoimmune paraneoplastic syndrome.
AB - The Lambert-Eaton myasthenic syndrome (LES) is an autoimmune presynaptic disorder of peripheral cholinergic neurotransmission in which there is often an associated small cell lung carcinoma (SCC). SCC lines established from patients with and without LES exhibit a Ca2+ influx response to depolarization by K+ that is consistent with the presence of voltage-gated Ca2+ channels. Autoantibodies antagonistic to SCC Ca2+ channel activity were found exclusively in patients with LES, independent of cancer status. Depolarization-induced uptake of 45 Ca2+ by SCC lines was reduced maximally after 3–4 days of exposure to serum immunoglobulins from 14 of 19 LES patients, while 53 control immunoglobulins (including patients with SCC, other tumors, other paraneoplastic syndromes, and other neurological and autoimmune diseases) were without effect. The snail neurotoxin ω-contoxin of subtype GVIA, which is a specific antagonist of presynaptic Ca2+ channels, inhibited K+-stimulated Ca2+ uptake in a dose-dependent manner that was essentially irreversible. Adenosine, reported to be a specific antagonist of neuronal Ca2+ channels, also impaired voltage-stimulated Ca2+ influx in SCC. Use of LES patients9 IgG and ω-conotoxin in further studies of SCC may facilitate identification and purification of the LES antigen(s) and yield a quantitative serological test for diagnosing this autoimmune paraneoplastic syndrome.
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M3 - Article
C2 - 2457429
AN - SCOPUS:0023676250
SN - 0008-5472
VL - 48
SP - 4719
EP - 4724
JO - Cancer research
JF - Cancer research
IS - 17
ER -