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Emerging Concepts in Ion Channel Biophysics
Poster Abstracts
52
40-POS
Board 40
Pharmacological Effects Exerted by Polypeptide Fractions Extracted from Centruroides
Noxius Venom on the Oncogenic Channel Kv10.1/Eag1
Erika Monserrat Torres-Morales
1
, Arlet Loza-Huerta
1
, Fredy Coronas-Valderrama
2
, Arturo
Hernández-Cruz
1
, Lourival Possani
2
, Arturo Picones
1
, Enoch Luis Baltazar
2
, Cesar Oliver Lara
Figueroa
2
1
Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, UNAM;
2
Instituto de
Biotecnología, UNAM.
The potassium channel Ether-a-go-go-1 (Eag1, KV10.1, KCNH1) is found in 70% of tumoral cells
and has been linked to processes of cell proliferation, angiogenesis, migration, survival and
invasion in a variety of cancers. All this has led to propose Kv10.1 as a relevant therapeutic target.
Here we report the evaluation of the action of different polypeptide fractions, isolated by HPLC
from the venom of the scorpion Centruroides noxius, on the functional activity of KV10.1
heterologously and stably expressed in HEK293 cells. By means of automated fluorescence
technology, measuring Thallium ion influx through Kv10.1, 20 different polypeptide fractions
were initially screened, 2 of them were identified as inhibitory hits (Tl influx reduction > 30%)
and were further re-fractionated by HPLC. The pharmacological activity of these newly isolated
fractions were analyzed by manual patch-clamp electrophysiology. Outward potassium currents
through Kv10.1 were measured in response to 200 ms voltage steps from -100 to +50 mv in 10
mV increments applied every 5 s and from a holding voltage of -70 mV. The polypeptide fraction
named CnMt9 showed a clear dose-dependent inhibitory effect, characterized by an ID50 of 14.2
ng/ml. Conductance-voltage relationship fitted with a Boltzmann equation showed that CnMt9
shifts the half-activation voltage (V1/2) from 4.7 mV to 23.8 mV and increased the slope factor
from
/ml) and to V1/2 >100 mV and slope factor
Supported by CONACyT (México) grants 279820 (Laboratorio Nacional de Canalopatías and CB
240305.