RESUMEN
Calcium ions regulate a wide array of physiological functions including cell differentiation, proliferation, muscle contraction, neurotransmission, and fertilization. The endoplasmic reticulum (ER) is the major intracellular Ca2+ store and cellular events that induce ER store depletion (e.g., activation of inositol 1,4,5-triphosphate (IP3) receptors) trigger a refilling process known as store-operated calcium entry (SOCE). It requires the intricate interaction between the Ca2+ sensing stromal interaction molecules (STIM) located in the ER membrane and the channel forming Orai proteins in the plasma membrane (PM). The resulting active STIM/Orai complexes form highly selective Ca2+ channels that facilitate a measurable Ca2+ influx into the cytosol followed by successive refilling of the ER by the sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA). STIM and Orai have attracted significant therapeutic interest, as enhanced SOCE has been associated with several cancers, and mutations in STIM and Orai have been linked to immunodeficiency, autoimmune, and muscular diseases. 2-Aminoethyl diphenylborinate (2-APB) is a known modulator and depending on its concentration can inhibit or enhance SOCE. We have synthesized several novel derivatives of 2-APB, introducing halogen and other small substituents systematically on each position of one of the phenyl rings. Using a fluorometric imaging plate reader (FLIPR) Tetra-based calcium imaging assay we have studied how these structural changes of 2-APB affect the SOCE modulation activity at different compound concentrations in MDA-MB-231 breast cancer cells. We have discovered 2-APB derivatives that block SOCE at low concentrations, at which 2-APB usually enhances SOCE.
Asunto(s)
Compuestos de Boro/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Proteínas de Neoplasias/genética , Proteína ORAI1/genética , Molécula de Interacción Estromal 1/genética , Moléculas de Interacción Estromal/genética , Animales , Compuestos de Boro/síntesis química , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Calcio/metabolismo , Señalización del Calcio/efectos de los fármacos , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/genética , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Complejos Multiproteicos/antagonistas & inhibidores , Complejos Multiproteicos/genética , Proteínas de Neoplasias/antagonistas & inhibidores , Proteína ORAI1/química , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/genética , Molécula de Interacción Estromal 1/antagonistas & inhibidores , Moléculas de Interacción Estromal/antagonistas & inhibidoresRESUMEN
Effective therapy of hypertension represents a key strategy for reducing the burden of cardiovascular disease and its associated mortality. The significance of voltage dependent L-type Ca²âº channels to Ca²âº influx, and of their regulatory mechanisms in the development of heart disease, is well established. A wide variety of L-type Ca²âº channel inhibitors and Ca²âº antagonists have been found to be beneficial not only in the treatment of hypertension, but also in myocardial infarction and heart failure. Over the past two decades, another class of Ca²âº channel - the voltage independent store-operated Ca²âº channel - has been implicated in the regulation and fine tuning of Ca²âº entry in both cardiac and smooth muscle cells. Store-operated Ca²âº channels are activated by the depletion of Ca²âº stores within the endoplasmic/sarcoplasmic reticulum, or by low levels of cytosolic Ca²âº, thereby facilitating agonist-induced Ca²âº influx. Store-operated Ca²âº entry through this pivotal pathway involves both stromal interaction molecule (STIM) and Orai channels. Different degrees of changes in these proteins are considered to promote Ca²âº entry and hence contribute to the pathogenesis of cardiovascular dysfunction. Several blockers of store-operated Ca²âº channels acting at the level of both STIM and Orai channels have been shown to depress Ca²âº influx and lower blood pressure. However, their specificity, safety, and clinical significance remain to be established. Thus, there is an ongoing challenge in the development of selective inhibitors of store-operated Ca²âº channels that act in vascular smooth muscles for the improved treatment of hypertension.
