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Molecular Interplay Between Non-Coding RNAs and Connexins and Its Possible Role in Cancer
(MDPI AG, 2025-03-12)
Pablo Pérez-Moreno
;
Juan P. Muñoz
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RETAMAL LUCERO, MAURICIO ANTONIO
Non-coding RNAs (ncRNAs) are sequences that do not encode for proteins and play key roles in different cellular processes, including cell proliferation and differentiation. On the other hand, connexins (Cxs) are transmembrane proteins that principally allow intercellular communication. In pathological conditions such as cancer, there is a deregulation in the expression and/or function of ncRNAs and Cxs, which in turn leads to an enhancement in the aggressive phenotype, such as a greater proliferative and invasive capacity. This suggests a plausible interplay between ncRNAs and Cxs. Based on that, this review aims to summarize the current knowledge regarding this relationship and to analyze how it may influence the development of aggressive traits in cancer cells and the clinicopathological features of cancer patients. Finally, we discuss the potential of ncRNAs and Cxs as promising clinical biomarkers for cancer diagnosis, prognosis, and therapeutic targeting.
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Connexin46 in the nucleus of cancer cells: a possible role as transcription modulator
(Springer Science and Business Media LLC, 2025-03-27)
Ainoa Fernández-Olivares
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Viviana P Orellana
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Jesús Llanquinao
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NUÑEZ VASQUEZ, GONZALO ESTEBAN
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Pablo Pérez-Moreno
Scopus© Citations 1 10
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The Unexplored Role of Connexin Hemichannels in Promoting Facioscapulohumeral Muscular Dystrophy Progression
(MDPI AG, 2025-01-04)
Macarena Díaz-Ubilla
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RETAMAL LUCERO, MAURICIO ANTONIO
<jats:p>DUX4 is typically a repressed transcription factor, but its aberrant activation in Facioscapulohumeral Muscular Dystrophy (FSHD) leads to cell death by disrupting muscle homeostasis. This disruption affects crucial processes such as myogenesis, sarcolemma integrity, gene regulation, oxidative stress, immune response, and many other biological pathways. Notably, these disrupted processes have been associated, in other pathological contexts, with the presence of connexin (Cx) hemichannels—transmembrane structures that mediate communication between the intracellular and extracellular environments. Thus, hemichannels have been implicated in skeletal muscle atrophy, as observed in human biopsies and animal models of Duchenne Muscular Dystrophy, Becker Muscular Dystrophy, and Dysferlinopathies, suggesting a potentially shared mechanism of muscle atrophy that has not yet been explored in FSHD. Despite various therapeutic strategies proposed to manage FSHD, no treatment or cure is currently available. This review summarizes the current understanding of the mechanisms underlying FSHD progression, with a focus on hormones, inflammation, reactive oxygen species (ROS), and mitochondrial function. Additionally, it explores the potential of targeting hemichannels as a therapeutic strategy to slow disease progression by preventing the spread of pathogenic factors between muscle cells.</jats:p>
5
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Lack of canonical activities of connexins in highly aggressive human prostate cancer cells
(Springer Science and Business Media LLC, 2024-12-19)
Catalina Asencio
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Loreto Véliz
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Emilia Flores-Faúndez
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Lorena Azócar
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Carolina E. Echeverría
<jats:title>Abstract</jats:title><jats:p>Connexins (Cxs) have the ability to form channels that allow the exchange of ions/metabolites between adjacent cells (gap junction channels, GJC) or between the intra- and extra-cellular compartments (hemichannels, HC). Cxs were initially classified as tumor suppressors. However, more recently, it has been shown that Cxs exert anti- and pro-tumorigenic effects depending on the cell and tissue context. In prostate cancer (PCa), the expression and functionality of Cxs remain highly controversial. Here, we analyzed the expression pattern of Cx26, Cx32, Cx37, Cx40, Cx43 and Cx45 in PCa cell lines with increasing levels of tumor aggressiveness (LNCaP < LNCaP-C4-2 < Du-145 < PC-3). In addition, GJ and HC activities were evaluated in the PCa cell lines using dye coupling and dye uptake assays, respectively. Lastly, the cellular localization of Cx26, Cx32, and Cx43 was analyzed in LNCaP and PC-3 cell lines using immunofluorescence analyses. Our results showed a positive association between the mRNA levels of Cx26, Cx37 and Cx45 and the degree of aggressiveness of PCa cells, a negative association in the case of Cx32 and Cx43, and no clear pattern for Cx40. At the protein level, a negative relationship between the expression of Cx26, Cx32 and Cx43 and the degree of aggressiveness of PCa cell lines was observed. No significant differences were observed for the expression of Cx37, Cx40, and Cx45 in PCa cell lines. At the functional level, only LNCaP cells showed moderate GJ activity and LNCaP and LNCaP-C4-2 cells showed HC activity. Immunofluorescence analyses confirmed that the majority of Cx26, Cx32, and Cx43 expression was localized in the cytoplasm of both LNCaP and PC3 cell lines. This data indicated that GJ and HC activities were moderately detected only in the less aggressive PCa cells, which suggest that Cxs expression in highly aggressive PCa cells could be associated to channel-independent roles.</jats:p>
Scopus© Citations 3 1
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Acute activation of hemichannels by ethanol leads to Ca2+-dependent gliotransmitter release in astrocytes
(2024)
Gonzalo I. Gómez
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Claudia García-Rodríguez
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Jesús E. Marillán
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Sergio A. Vergara
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Tanhia F. Alvear
<jats:p>Multiple studies have demonstrated that acute ethanol consumption alters brain function and cognition. Nevertheless, the mechanisms underlying this phenomenon remain poorly understood. Astrocyte-mediated gliotransmission is crucial for hippocampal plasticity, and recently, the opening of hemichannels has been found to play a relevant role in this process. Hemichannels are plasma membrane channels composed of six connexins or seven pannexins, respectively, that oligomerize around a central pore. They serve as ionic and molecular exchange conduits between the cytoplasm and extracellular milieu, allowing the release of various paracrine substances, such as ATP, D-serine, and glutamate, and the entry of ions and other substances, such as Ca<jats:sup>2+</jats:sup> and glucose. The persistent and exacerbated opening of hemichannels has been associated with the pathogenesis and progression of several brain diseases for at least three mechanisms. The uncontrolled activity of these channels could favor the collapse of ionic gradients and osmotic balance, the release of toxic levels of ATP or glutamate, cell swelling and plasma membrane breakdown and intracellular Ca<jats:sup>2+</jats:sup> overload. Here, we evaluated whether acute ethanol exposure affects the activity of astrocyte hemichannels and the possible repercussions of this phenomenon on cytoplasmatic Ca<jats:sup>2+</jats:sup> signaling and gliotransmitter release. Acute ethanol exposure triggered the rapid activation of connexin43 and pannexin1 hemichannels in astrocytes, as measured by time-lapse recordings of ethidium uptake. This heightened activity derived from a rapid rise in [Ca<jats:sup>2+</jats:sup>]<jats:sub>i</jats:sub> linked to extracellular Ca<jats:sup>2+</jats:sup> influx and IP<jats:sub>3</jats:sub>-evoked Ca<jats:sup>2+</jats:sup> release from intracellular Ca<jats:sup>2+</jats:sup> stores. Relevantly, the acute ethanol-induced activation of hemichannels contributed to a persistent secondary increase in [Ca<jats:sup>2+</jats:sup>]<jats:sub>i</jats:sub>. The [Ca<jats:sup>2+</jats:sup>]<jats:sub>i</jats:sub>-dependent activation of hemichannels elicited by ethanol caused the increased release of ATP and glutamate in astroglial cultures and brain slices. Our findings offer fresh perspectives on the potential mechanisms behind acute alcohol-induced brain abnormalities and propose targeting connexin43 and pannexin1 hemichannels in astrocytes as a promising avenue to prevent deleterious consequences of alcohol consumption.</jats:p>
11Scopus© Citations 4
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Gap junction channels and hemichannels in the CNS: Regulation by signaling molecules
(2013)
Juan A. Orellana
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Agustín D. Martinez
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RETAMAL LUCERO, MAURICIO ANTONIO
Scopus© Citations 83 1
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Connexins in Cancer, the Possible Role of Connexin46 as a Cancer Stem Cell-Determining Protein
(2023)
Isidora M. León-Fuentes
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María G. Salgado-Gil
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María S. Novoa
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RETAMAL LUCERO, MAURICIO ANTONIO
<jats:p>Cancer is a widespread and incurable disease caused by genetic mutations, leading to uncontrolled cell proliferation and metastasis. Connexins (Cx) are transmembrane proteins that facilitate intercellular communication via hemichannels and gap junction channels. Among them, Cx46 is found mostly in the eye lens. However, in pathological conditions, Cx46 has been observed in various types of cancers, such as glioblastoma, melanoma, and breast cancer. It has been demonstrated that elevated Cx46 levels in breast cancer contribute to cellular resistance to hypoxia, and it is an enhancer of cancer aggressiveness supporting a pro-tumoral role. Accordingly, Cx46 is associated with an increase in cancer stem cell phenotype. These cells display radio- and chemoresistance, high proliferative abilities, self-renewal, and differentiation capacities. This review aims to consolidate the knowledge of the relationship between Cx46, its role in forming hemichannels and gap junctions, and its connection with cancer and cancer stem cells.</jats:p>
Scopus© Citations 3 2
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Novel Pannexin-1-Coupled Signaling Cascade Involved in the Control of Endothelial Cell Function and NO-Dependent Relaxation
(2021)
Mauricio A. Lillo
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Pablo S. Gaete
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Mariela Puebla
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Pía C. Burboa
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Inés Poblete
<jats:p>Deletion of pannexin-1 (Panx-1) leads not only to a reduction in endothelium-derived hyperpolarization but also to an increase in NO-mediated vasodilation. Therefore, we evaluated the participation of Panx-1-formed channels in the control of membrane potential and [Ca2+]i of endothelial cells. Changes in NO-mediated vasodilation, membrane potential, superoxide anion (O2⋅–) formation, and endothelial cell [Ca2+]i were analyzed in rat isolated mesenteric arterial beds and primary cultures of mesenteric endothelial cells. Inhibition of Panx-1 channels with probenecid (1 mM) or the Panx-1 blocking peptide 10Panx (60 μM) evoked an increase in the ACh (100 nM)-induced vasodilation of KCl-contracted mesenteries and in the phosphorylation level of endothelial NO synthase (eNOS) at serine 1177 (P-eNOSS1177) and Akt at serine 473 (P-AktS473). In addition, probenecid or 10Panx application activated a rapid, tetrodotoxin (TTX, 300 nM)-sensitive, membrane potential depolarization and [Ca2+]i increase in endothelial cells. Interestingly, the endothelial cell depolarization was converted into a transient spike after removing Ca2+ ions from the buffer solution and in the presence of 100 μM mibefradil or 10 μM Ni2+. As expected, Ni2+ also abolished the increment in [Ca2+]i. Expression of Nav1.2, Nav1.6, and Cav3.2 isoforms of voltage-dependent Na+ and Ca2+ channels was confirmed by immunocytochemistry. Furthermore, the Panx-1 channel blockade was associated with an increase in O2⋅– production. Treatment with 10 μM TEMPOL or 100 μM apocynin prevented the increase in O2⋅– formation, ACh-induced vasodilation, P-eNOSS1177, and P-AktS473 observed in response to Panx-1 inhibition. These findings indicate that the Panx-1 channel blockade triggers a novel complex signaling pathway initiated by the sequential activation of TTX-sensitive Nav channels and Cav3.2 channels, leading to an increase in NO-mediated vasodilation through a NADPH oxidase-dependent P-eNOSS1177, which suggests that Panx-1 may be involved in the endothelium-dependent control of arterial blood pressure.</jats:p>
7Scopus© Citations 16
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Over-activated hemichannels: A possible therapeutic target for human diseases
(2021)
Mauricio A. Retamal
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Ainoa Fernandez-Olivares
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Jimmy Stehberg
Scopus© Citations 11 13
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Skeletal Muscle Atrophy Induced by Diabetes Is Mediated by Non-Selective Channels and Prevented by Boldine
(2023)
Luis A. Cea
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Walter Vásquez
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Romina Hernández-Salinas
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Alejandra Z. Vielma
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Mario Castillo-Ruiz
<jats:p>Individuals with diabetes mellitus present a skeletal muscle myopathy characterized by atrophy. However, the mechanism underlying this muscular alteration remains elusive, which makes it difficult to design a rational treatment that could avoid the negative consequences in muscles due to diabetes. In the present work, the atrophy of skeletal myofibers from streptozotocin-induced diabetic rats was prevented with boldine, suggesting that non-selective channels inhibited by this alkaloid are involved in this process, as has previously shown for other muscular pathologies. Accordingly, we found a relevant increase in sarcolemma permeability of skeletal myofibers of diabetic animals in vivo and in vitro due to de novo expression of functional connexin hemichannels (Cx HCs) containing connexins (Cxs) 39, 43, and 45. These cells also expressed P2X7 receptors, and their inhibition in vitro drastically reduced sarcolemma permeability, suggesting their participation in the activation of Cx HCs. Notably, sarcolemma permeability of skeletal myofibers was prevented by boldine treatment that blocks Cx43 and Cx45 HCs, and now we demonstrated that it also blocks P2X7 receptors. In addition, the skeletal muscle alterations described above were not observed in diabetic mice with myofibers deficient in Cx43/Cx45 expression. Moreover, murine myofibers cultured for 24 h in high glucose presented a drastic increase in sarcolemma permeability and levels of NLRP3, a molecular member of the inflammasome, a response that was also prevented by boldine, suggesting that, in addition to the systemic inflammatory response found in diabetes, high glucose can promote the expression of functional Cx HCs and activation of the inflammasome in skeletal myofibers. Therefore, Cx43 and Cx45 HCs play a critical role in myofiber degeneration, and boldine could be considered a potential therapeutic agent to treat muscular complications due to diabetes.</jats:p>
5Scopus© Citations 18

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