Hydrogen Sulfide Promotes Proliferation of HT-29 Colon Cancer Cells in a Mitochondria-independent Pathway (original) (raw)
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Scientific Reports, 2016
Therapeutic manipulation of the gasotransmitter hydrogen sulfide (H 2 S) has recently been proposed as a novel targeted anticancer approach. Here we show that human lung adenocarcinoma tissue expresses high levels of hydrogen sulfide (H 2 S) producing enzymes, namely, cystathionine beta-synthase (CBS), cystathionine gamma lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), in comparison to adjacent lung tissue. In cultured lung adenocarcinoma but not in normal lung epithelial cells elevated H 2 S stimulates mitochondrial DNA repair through sulfhydration of EXOG, which, in turn, promotes mitochondrial DNA repair complex assembly, thereby enhancing mitochondrial DNA repair capacity. In addition, inhibition of H 2 S-producing enzymes suppresses critical bioenergetics parameters in lung adenocarcinoma cells. Together, inhibition of H 2 S-producing enzymes sensitize lung adenocarcinoma cells to chemotherapeutic agents via induction of mitochondrial dysfunction as shown in in vitro and in vivo models, suggesting a novel mechanism to overcome tumor chemoresistance. H 2 S is produced in mammalian cells by three distinct enzymes, cystathionine beta-synthase (CBS), cystathionine gamma lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST); during methionine/transsulfuration pathway 1-3. Deregulation of either H 2 S production and/or its downstream actions have been implicated in the pathophysiology of several diseases, including cardiovascular disease, shock, inflammation, diabetes, metabolic syndromes and neurodegeneration 4-11. In connection with cancer, we have previously showed a marked increase in the expression of CBS in colorectal cancer cells (compared to the surrounding normal mucosal margin), which was also recapitulated in multiple colon cancer cell lines 12. ShRNA-mediated silencing, as well as pharmacological inhibition of CBS caused a significant inhibition of the proliferation of colon cancer cells in vitro and in vivo (in tumor-bearing nude mice). Also, silencing or inhibition of CBS suppressed cellular bioenergetics of the colon cancer cells 12. The importance of the CBS/H 2 S in the promotion of cell proliferation and cellular bioenergetics has subsequently been confirmed in ovarian cancer 13 and breast cancer 14. H 2 S generated by overexpressed CSE, has been implicated in melanoma 15. In addition a rapidly increasing body of literature implicates the endogenously generated H 2 S to vascular relaxation and angiogenesis, cell proliferation, mitochondrial function, and cell
Effects of hydrogen sulfide on mitochondrial function and cellular bioenergetics
Redox Biology, 2021
Hydrogen sulfide (H 2 S) was once considered to have only toxic properties, until it was discovered to be an endogenous signaling molecule. The effects of H 2 S are dose dependent, with lower concentrations being beneficial and higher concentrations, cytotoxic. This scenario is especially true for the effects of H 2 S on mitochondrial function, where higher concentrations of the gasotransmitter inhibit the electron transport chain, and lower concentrations stimulate bioenergetics in multiple ways. Here we review the role of H 2 S in mitochondrial function and its effects on cellular physiology.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2010
Sulfide (H 2 S) is an inhibitor of mitochondrial cytochrome oxidase comparable to cyanide. In this study, poisoning of cells was observed with sulfide concentrations above 20 µM. Sulfide oxidation has been shown to take place in organisms/cells naturally exposed to sulfide. Sulfide is released as a result of metabolism of sulfur containing amino acids. Although in mammals sulfide exposure is not thought to be quantitatively important outside the colonic mucosa, our study shows that a majority of mammalian cells, by means of the mitochondrial sulfide quinone reductase (SQR), avidly consume sulfide as a fuel. The SQR activity was found in mitochondria isolated from mouse kidneys, liver, and heart. We demonstrate the precedence of the SQR over the mitochondrial complex I. This explains why the oxidation of the mineral substrate sulfide takes precedence over the oxidation of other (carbon-based) mitochondrial substrates. Consequently, if sulfide delivery rate remains lower than the SQR activity, cells maintain a non-toxic sulfide concentration (b 1 µM) in their external environment. In the colonocyte cell line HT-29, sulfide oxidation provided the first example of reverse electron transfer in living cells, such a transfer increasing sulfide tolerance. However, SQR activity was not detected in brain mitochondria and neuroblastoma cells. Consequently, the neural tissue would be more sensitive to sulfide poisoning. Our data disclose new constraints concerning the emerging signaling role of sulfide.
Molecular Functions of Hydrogen Sulfide in Cancer
Pathophysiology, 2021
Hydrogen sulfide (H2S) is a gasotransmitter that exerts a multitude of functions in both physiologic and pathophysiologic processes. H2S-synthesizing enzymes are increased in a variety of human malignancies, including colon, prostate, breast, renal, urothelial, ovarian, oral squamous cell, and thyroid cancers. In cancer, H2S promotes tumor growth, cellular and mitochondrial bioenergetics, migration, invasion, angiogenesis, tumor blood flow, metastasis, epithelia–mesenchymal transition, DNA repair, protein sulfhydration, and chemotherapy resistance Additionally, in some malignancies, increased H2S-synthesizing enzyme expression correlates with a worse prognosis and a higher tumor stage. Here we review the role of H2S in cancer, with an emphasis on the molecular mechanisms by which H2S promotes cancer development, progression, dedifferentiation, and metastasis.
S-Sulfhydration of ATP synthase by hydrogen sulfide stimulates mitochondrial bioenergetics
Pharmacological research, 2016
Mammalian cells can utilize hydrogen sulfide (H2S) to support mitochondrial respiration. The aim of our study was to explore the potential role of S-sulfhydration (a H2S-induced posttranslational modification, also known as S-persulfidation) of the mitochondrial inner membrane protein ATP synthase (F1F0 ATP synthase/Complex V) in the regulation of mitochondrial bioenergetics. Using a biotin switch assay, we have detected S-sulfhydration of the α subunit (ATP5A1) of ATP synthase in response to exposure to H2S in vitro. The H2S generator compound NaHS induced S-sulfhydration of ATP5A1 in HepG2 and HEK293 cell lysates in a concentration-dependent manner (50-300μM). The activity of immunocaptured mitochondrial ATP synthase enzyme isolated from HepG2 and HEK293 cells was stimulated by NaHS at low concentrations (10-100nM). Site-directed mutagenesis of ATP5A1 in HEK293 cells demonstrated that cysteine residues at positions 244 and 294 are subject to S-sulfhydration. The double mutant ATP ...
The Therapeutic Potential of Cystathionine β-Synthetase/Hydrogen Sulfide Inhibition in Cancer
Antioxidants & Redox Signaling, 2015
Significance: Cancer represents a major socioeconomic problem; there is a significant need for novel therapeutic approaches targeting tumor-specific pathways. Recent Advances: In colorectal and ovarian cancers, an increase in the intratumor production of hydrogen sulfide (H 2 S) from cystathionine b-synthase (CBS) plays an important role in promoting the cellular bioenergetics, proliferation, and migration of cancer cells. It also stimulates peritumor angiogenesis inhibition or genetic silencing of CBS exerts antitumor effects both in vitro and in vivo, and potentiates the antitumor efficacy of anticancer therapeutics. Critical Issues: Recently published studies are reviewed, implicating CBS overexpression and H 2 S overproduction in tumor cells as a tumorgrowth promoting ''bioenergetic fuel'' and ''survival factor,'' followed by an overview of the experimental evidence demonstrating the anticancer effect of CBS inhibition. Next, the current state of the art of pharmacological CBS inhibitors is reviewed, with special reference to the complex pharmacological actions of aminooxyacetic acid. Finally, new experimental evidence is presented to reconcile a controversy in the literature regarding the effects of H 2 S donor on cancer cell proliferation and survival. Future Directions: From a basic science standpoint, future directions in the field include the delineation of the molecular mechanism of CBS upregulation of cancer cells and the delineation of the interactions of H 2 S with other intracellular pathways of cancer cell metabolism and proliferation. From the translational science standpoint, future directions include the translation of the recently emerging roles of H 2 S in cancer into human diagnostic and therapeutic approaches. Antioxid. Redox Signal. 22, 424-448. Biological Effects of H 2 S with Relevance for Cancer Biology H 2 S, as a vasodilator and pro-angiogenic mediator Vasorelaxation is one of the first recognized biological effects of H 2 S. Often compared with NO, H 2 S exerts a concentration-dependent vasodilatory effect in blood vessels. The mechanisms of H 2 S-mediated vasodilation include the activation of K ATP channels, a variety of other channels, inhibition of phosphodiesterases, and a synergy with NO (132).
Biochimica et Biophysica Acta (BBA) - General Subjects, 2005
Hydrogen sulfide (H 2 S), a bacterial metabolite present in the lumen of the large intestine, is able to exert deleterious effects on the colonic epithelium. The mechanisms involved are still poorly understood, the reported effect of sulfide being its capacity to reduce n-butyrate hoxidation in colonocytes. In this work, we studied both the acute effect of the sodium salt of H 2 S on human colonic epithelial cell metabolism and the adaptative response of these cells to the pre-treatment with this agent. Using the human colon carcinoma epithelial HT-29 Glc À/+ cell model, we found that the acute effect of millimolar concentrations of NaHS was to inhibit l-glutamine, n-butyrate and acetate oxidation in a dosedependent manner. Using micromolar concentrations of NaHS, a comparable effect but largely reversible was observed for O 2 consumption and cytochrome c oxidase activity. Pre-treatment with 1 mM NaHS induced several adaptative responses. Firstly, increased lactate release and decreased cellular oxygen consumption evidenced a Pasteur-like effect which only partly compensated for the altered mitochondrial ATP production. Thus, a decrease in the proliferation rate with a constant adenylate charge was observed. Secondly, in these pre-treated cells, NaHS induced a hypoxia-like effect on cytochrome c oxidase subunits I and II which were decreased. Thirdly, a mild uncoupling of mitochondrial respiration possibly resulting from an increase of UCP2 protein was observed. The NaHS antimitotic activity was not due to cellular apoptosis and/or necrosis but to a proportional slowdown in all cell cycle phases. These results are compatible with a metabolic adaptative response of the HT-29 colonic epithelial cells to sulfide-induced O 2 consumption reduction which, through the maintenance of a constant energetic load and an increased mitochondrial proton leak, would participate in the preservation of cellular viability. D
A protective role of hydrogen sulfide against oxidative stress in rat gastric mucosal epithelium
Toxicology, 2007
We investigated effect of hydrogen sulfide (H 2 S) on oxidative stress-caused cell death in gastric mucosal epithelial cells. In rat normal gastric epithelial RGM1 cells, NaHS, a H 2 S donor, at 1.5 mM strongly suppressed hydrogen peroxide (H 2 O 2 )-caused cell death, while it slightly augmented the H 2 O 2 toxicity at 0.5-1 mM. The protective effect of NaHS was abolished by inhibitors of MEK or JNK, but not of p38 MAP kinase. NaHS at 1.5 mM actually phosphorylated ERK and JNK in RGM1 cells. Glibenclamide, an ATP-sensitive K + (K + ATP ) channel inhibitor, did not affect the protective effect of NaHS, although mRNAs for K + ATP channel subunits, Kir6.1 and SUR1, were detected in RGM1 cells. In anesthetized rats, oral administration of NaHS protected against gastric mucosal lesion caused by ischemia-reperfusion. These results suggest that NaHS/H 2 S may protect gastric mucosal epithelial cells against oxidative stress through stimulation of MAP kinase pathways, a therapeutic dose range being very narrow.
Proceedings of the National Academy of Sciences of the United States of America, 2013
The physiological functions of hydrogen sulfide (H2S) include vasorelaxation, stimulation of cellular bioenergetics, and promotion of angiogenesis. Analysis of human colon cancer biopsies and patient-matched normal margin mucosa revealed the selective up-regulation of the H2S-producing enzyme cystathionine-β-synthase (CBS) in colon cancer, resulting in an increased rate of H2S production. Similarly, colon cancer-derived epithelial cell lines (HCT116, HT-29, LoVo) exhibited selective CBS up-regulation and increased H2S production, compared with the nonmalignant colonic mucosa cells, NCM356. CBS localized to the cytosol, as well as the mitochondrial outer membrane. ShRNA-mediated silencing of CBS or its pharmacological inhibition with aminooxyacetic acid reduced HCT116 cell proliferation, migration, and invasion; reduced endothelial cell migration in tumor/endothelial cell cocultures; and suppressed mitochondrial function (oxygen consumption, ATP turnover, and respiratory reserve capa...
Oxidation of hydrogen sulfide by human liver mitochondria
Nitric Oxide, 2014
Hydrogen sulfide (H 2 S) is the third gasotransmitter discovered. Sulfide shares with the two others (NO and CO) the same inhibiting properties towards mitochondrial respiration. However, in contrast with NO or CO, sulfide at concentrations lower than the toxic (lM) level is an hydrogen donor and a substrate for mitochondrial respiration. This is due to the activity of a sulfide quinone reductase found in a large majority of mitochondria. An ongoing study of the metabolic state of liver in obese patients allowed us to evaluate the sulfide oxidation capacity with twelve preparations of human liver mitochondria. The results indicate relatively high rates of sulfide oxidation with a large variability between individuals. These observations made with isolated mitochondria appear in agreement with the main characteristics of sulfide oxidation as established before with the help of cellular models.