Search Results (70)

Background/Objectives: Hydrogen sulfide (H₂S) is a vasorelaxant gas and exerts anti-oxidative, anti-inflammatory, and cytoprotective effects. H₂S has been implicated in regulating placental vaso-activity and angiogenesis. It is believed that abnormal trophoblast production of vasodilators and angiogenic factors contributes to pre-eclampsia development. However, little is known about whether aberrant H₂S production is present in placental trophoblasts from pre-eclamptic pregnancies. Methods: Trophoblasts were isolated from normal and pre-eclamptic placentas. After incubation, cell production of H₂S in the culture medium and the cellular levels of H₂S were analyzed by reversed phase high-performance liquid chromatography (RP-HPLC). Expression levels of the three key H₂S converting enzymes, cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), were determined by immunohistochemistry. The protein expression of CBS and CSE was assessed by Western blot analysis. Results: (1) Trophoblast production and cellular levels of H₂S were significantly reduced in cells from pre-eclamptic vs. normal placentas; (2) free H₂S production was increased in a time-dependent manner in cultured trophoblasts from normal, but not from pre-eclamptic, placentas; and (3) strong CBS and CSE expression was seen in trophoblasts from normal, as opposed to pre-eclamptic, placentas. Reduced CBS and CSE expression in trophoblasts from pre-eclamptic vs. normal placentas were confirmed by Western blot analysis; and (4) 3-MST expression was undetachable in both normal and pre-eclamptic placentas, but 3-MST expression was strongly expressed in the first and second trimester placentas. Conclusions: These data provide plausible evidence that downregulation of CBS and CSE, but not 3-MST, expression may be responsible for reduced free H₂S production and decreased cellular H₂S levels in pre-eclamptic placentas. Our data provide further evidence that expression of 3-MST in placental trophoblasts is likely gestational age (developmental)-dependent. Full article

Exercise plays a crucial role in maintaining metabolic health, enhancing muscle function, and improving insulin sensitivity, thereby preventing metabolic diseases such as type 2 diabetes. Emerging evidence highlights the significance of the cystathionine γ-lyase (CSE)/hydrogen sulfide (H₂S) signaling pathway as a pivotal regulator in the molecular and physiological adaptations induced by exercise. This review comprehensively examines the biosynthesis and metabolism of H₂S, its distribution in different muscle tissues, and the mechanisms by which CSE/H₂S influences muscle contraction, repair, and protein synthesis. Additionally, it explores how CSE/H₂S modulates insulin signaling pathways, glucose uptake, and lipid metabolism, thereby enhancing insulin sensitivity. The potential of H₂S donors as exercise supplements is also discussed, highlighting their ability to improve exercise performance and metabolic health. Current research advancements, including the application of multi-omics approaches, are reviewed to provide a deeper understanding of the complex molecular networks involved. Furthermore, the challenges and future directions in CSE/H₂S research are addressed, emphasizing the need for further mechanistic studies and clinical applications. This review underscores the therapeutic potential of targeting the CSE/H₂S pathway to optimize the benefits of exercise and improve metabolic health. Full article

In recent years, a number of synthetic potentiators of antibiotics have been discovered. Their action can significantly enhance the antibacterial effect and limit the spread of antibiotic resistance through inhibition of bacterial cystathionine-γ-lyase. To expand the known set of potentiators, we developed methods for the synthesis of five new representatives of 6-bromoindole derivatives—potential inhibitors of bacterial cystathionine-γ-lyase—namely potassium 3-amino-5-((6-bromoindolyl)methyl)thiophene-2-carboxylate (MNS2) and its 6-bromoindazole analogs (MNS3 and MNS4), along with two 6-broindazole analogs of the parent compound NL2. Their syntheses are based on 6-bromoindole, 6-bromoindazole and methyl 5-(bromomethyl)-3-((ethoxycarbonyl)amino)thiophene-2-carboxylate as the main building blocks, assembling the rest of the heterocyclic system on their basis at the nitrogen atom. We assessed the ability of the new inhibitors to potentiate the antimicrobial activity of gentamicin. Full article

Both hydrogen sulfide and endocannabinoids can protect the neural retina from toxic insults under in vitro and in vivo conditions. Purpose: The aim of the present study was two-fold: (a) to examine the neuroprotective action of cannabinoids [methanandamide and 2-arachidonyl glycerol (2-AG)] against hydrogen peroxide (H₂O₂)-induced oxidative damage in the isolated bovine retina and (b) to evaluate the role of endogenously biosynthesized hydrogen sulfide (H₂S) in the inhibitory actions of cannabinoids on the oxidative stress in the bovine retina. Methods: Isolated neural retinas from cows were exposed to oxidative damage using H₂O₂ (100 µM) for 10 min. When used, tissues were pretreated with methanandamide (1 nM–100 nM) and 2-AG (1–10 µM) for 30 min before a 10 min treatment with H₂O₂ (100 µM). In some experiments, retinas were pretreated with inhibitors of the biosynthesis of H₂S [cystathionine β-synthase/cystathionine γ-lyase (CBS/CSE), aminooxyacetic acid, AOAA 30 µM, or 3-mercaptopyruvate sulfurtransferase (3MST), α-keto-butyric acid, KBA 1 mM] and the CB1-receptor antagonist, AM251 (100 nM) for 30 min before treatment with methanandamide (1 nM–100 µM). Enzyme immunoassay measurement of 8-epi PGF2α (8-isoprostane) levels was performed to assess lipid peroxidation in retinal tissues. Results: In the presence of H₂O₂ (100 µM), methanandamide (1 nM–100 µM) and 2-AG (1–10 µM) significantly (p < 0.001) blocked the H₂O₂-induced elevation in 8-isoprostane levels in the isolated bovine retina. In the presence of the CB1 antagonist AM251 (100 nM), the effect of methanandamide (1 nM) on the H₂O₂-induced 8-isoprostane production was significantly (p < 0.001) attenuated. While AOAA (30 µM) had no significant (p > 0.05) effect on the inhibition of H₂O₂-induced oxidative stress elicited by methanandamide, KBA (1 mM) reversed the neuroprotective action of methanandamide. Conclusions: The cannabinoids, methanandamide and 2-AG can prevent H₂O₂-induced oxidative stress in the isolated bovine retina. The neuroprotective actions of cannabinoids are partially dependent upon the activation of the CB1 receptors and endogenous production of H₂S via the 3-MST/CAT pathway. Full article

Sodium thiosulfate (STS), a precursor of hydrogen sulfide (H₂S), has demonstrated antihypertensive properties. Previous studies have suggested that H₂S-based interventions can prevent hypertension in pediatric chronic kidney disease (CKD). However, the clinical application of STS is limited by its rapid release and intravenous administration. To address this, we developed a poly-lactic acid (PLA)-based nanoparticle system for sustained STS delivery and investigated whether weekly treatment with STS-loaded nanoparticles (NPs) could protect against hypertension in a juvenile CKD rat model. Male Sprague Dawley rats, aged three weeks, were fed a diet containing 0.5% adenine for three weeks to induce a model of pediatric CKD. STS-loaded NPs (25 mg/kg) were administered intravenously during weeks 6, 7, and 8, and at week 9, all rats were sacrificed. Treatment with STS-loaded NPs reduced systolic and diastolic blood pressure by 10 mm Hg and 8 mm Hg, respectively, in juvenile CKD rats. The protective effect of STS-loaded NPs was linked to increased renal expression of H₂S-producing enzymes, including cystathionine γ-lyase (CSE) and D-amino acid oxidase (DAO). Additionally, STS-loaded NP therapy restored nitric oxide (NO) signaling, increasing L-arginine levels, which were disrupted in CKD. Furthermore, the beneficial effects of STS-loaded NPs were associated with inhibition of the renin–angiotensin system (RAS) and the enhancement of the NO signaling pathway. Our findings suggest that STS-loaded NP treatment provides sustained STS delivery and effectively reduces hypertension in a juvenile CKD rat model, bringing us closer to the clinical translation of STS-based therapy for pediatric CKD-induced hypertension. Full article

Cystathionine γ-lyase (CSE) is the second enzyme in the trans-sulfuration pathway that converts cystathionine to cysteine. It is also one of three major enzymes responsible for the biosynthesis of hydrogen sulfide (H₂S). CSE is believed to be the major source of endogenous H₂S in the cardiovascular system, and the CSE/H₂S system plays a crucial role in a variety of physiological and pathological processes. However, the regulatory mechanism of the CSE/H₂S system is less well understood, especially at the post-translational level. Here, we demonstrated that the persulfidation of CSE inhibits its activity by ~2-fold in vitro. The loss of this post-translational modification in the presence of dithiothreitol (DTT) results in a reversal of basal activity. Cys137 was identified as the site for persulfidation by combining mass spectrometry, mutagenesis, activity analysis and streptavidin–biotin pull-down assays. To test the physiological relevance of the persulfidation regulation of CSE, human aortic vascular smooth muscle cells (HA-VSMCs) were incubated with vascular endothelial growth factor (VEGF), which is known to enhance endogenous H₂S levels. Under these conditions, consistent with the change tendency of the cellular H₂S level, the CSE persulfidation levels increased transiently and then gradually decreased to the basal level. Collectively, our study revealed a negative feedback regulation mechanism of the CSE/H₂S system via the persulfidation of CSE and demonstrated the potential for maintaining cellular H₂S homeostasis under oxidative stress conditions, particularly in tissues where CSE is a major source of H₂S. Full article

Background: Acute and chronic pre-traumatic cigarette smoke exposure increases morbidity and mortality after trauma and hemorrhage. In mice with a genetic deletion of the H₂S-producing enzyme cystathione-γ-lyase (CSE^−/−), providing exogenous H₂S using sodium thiosulfate (Na₂S₂O₃) improved organ function after chest trauma and hemorrhagic shock. Therefore, we evaluated the effect of Na₂S₂O₃ during resuscitation from blunt chest trauma and hemorrhagic shock on CSE^−/− mice with pre-traumatic cigarette smoke (CS) exposure. Since H₂S is well established as being able to modify energy metabolism, a specific focus was placed on whole-body metabolic pathways and mitochondrial respiratory activity. Methods: Following CS exposure, the CSE^−/− mice underwent anesthesia, surgical instrumentation, blunt chest trauma, hemorrhagic shock for over 1 h (target mean arterial pressure (MAP) ≈ 35 ± 5 mmHg), and resuscitation for up to 8 h comprising lung-protective mechanical ventilation, the re-transfusion of shed blood, fluid resuscitation, and continuous i.v. noradrenaline (NoA) to maintain an MAP ≥ 55 mmHg. At the start of the resuscitation, the mice randomly received either i.v. Na₂S₂O₃ (0.45 mg/g_bodyweight; n = 14) or the vehicle (NaCl 0.9%; n = 11). In addition to the hemodynamics, lung mechanics, gas exchange, acid–base status, and organ function, we quantified the parameters of carbohydrate, lipid, and protein metabolism using a primed continuous infusion of stable, non-radioactive, isotope-labeled substrates (gas chromatography/mass spectrometry) and the post-mortem tissue mitochondrial respiratory activity (“high-resolution respirometry”). Results: While the hemodynamics and NoA infusion rates did not differ, Na₂S₂O₃ was associated with a trend towards lower static lung compliance (p = 0.071) and arterial PO₂ (p = 0.089) at the end of the experiment. The direct, aerobic glucose oxidation rate was higher (p = 0.041) in the Na₂S₂O₃-treated mice, which resulted in lower glycemia levels (p = 0.050) and a higher whole-body CO₂ production rate (p = 0.065). The mitochondrial respiration in the heart, kidney, and liver tissue did not differ. While the kidney function was comparable, the Na₂S₂O₃-treated mice showed a trend towards a shorter survival time (p = 0.068). Conclusions: During resuscitation from blunt chest trauma and hemorrhagic shock in CSE^−/− mice with pre-traumatic CS exposure, Na₂S₂O₃ was associated with increased direct, aerobic glucose oxidation, suggesting a switch in energy metabolism towards preferential carbohydrate utilization. Nevertheless, treatment with Na₂S₂O₃ coincided with a trend towards worsened lung mechanics and gas exchange, and, ultimately, shorter survival. Full article

Early life stress (ELS) significantly increases the risk of chronic cardiovascular diseases and may cause neuroinflammation. This post hoc study, based on the material available from a previous study showing elevated “serum brain injury markers” in male control animals, examines the effect of sex and/or ELS on the cerebral and cardiac expression of the H₂S and oxytocin systems. Following approval by the Regional Council of Tübingen, a randomized controlled study was conducted on 12 sexually mature, uncastrated German Large White swine of both sexes. The control animals were separated from their mothers at 28–35 days, while the ELS group was separated at day 21. At 20–24 weeks, animals underwent anesthesia, ventilation, and surgical instrumentation. An immunohistochemical analysis of oxytocin, its receptor, and the H₂S-producing enzymes cystathionine-β-synthase and cystathionine-γ-lyase was performed on hypothalamic, prefrontal cortex, and myocardial tissue samples. Data are expressed as the % of positive tissue staining, and differences between groups were tested using a two-way ANOVA. The results showed no significant differences in the oxytocin and H₂S systems between groups; however, sex influenced the oxytocin system, and ELS affected the oxytocin and H₂S systems in a sex-specific manner. No immunohistochemical correlate to the elevated “serum brain injury markers” in male controls was identified. Full article

Background: We have evidence that hydrogen sulfide (H₂S)-releasing compounds can reduce intraocular pressure in normotensive and glaucomatous rabbits by increasing the aqueous humor (AH) outflow through the trabecular meshwork. Since H₂S has been reported to possess neuroprotective actions, the prevention of retinal ganglion cell loss is an important strategy in the pharmacotherapy of glaucoma. Consequently, the present study aimed to investigate the neuroprotective actions of H₂S-releasing compounds against hydrogen peroxide (H₂O₂)-induced oxidative stress in an isolated bovine retina. Materials and Methods: The isolated neural retinae were pretreated with a substrate for H₂S biosynthesis called L-cysteine, with the fast H₂S-releasing compound sodium hydrosulfide, and with a mitochondrial-targeting H₂S-releasing compound, AP123, for thirty minutes before a 30-min oxidative insult with H₂O₂ (100 µM). Lipid peroxidation was assessed via an enzyme immunoassay by measuring the stable oxidative stress marker, 8-epi PGF2α (8-isoprostane), levels in the retinal tissues. To determine the role of endogenous H₂S, studies were performed using the following biosynthesis enzyme inhibitors: aminooxyacetic acid (AOAA, 30 µM); a cystathione-β-synthase/cystathionine-γ-lyase (CBS/CSE) inhibitor, α–ketobutyric acid (KBA, 1 mM); and a 3-mercaptopyruvate-s-sulfurtransferase (3-MST) inhibitor, in the absence and presence of H₂S-releasing compounds. Results: Exposure of the isolated retinas to H₂O₂ produced a time-dependent (10–40 min) and concentration-dependent (30–300 µM) increase in the 8-isoprostane levels when compared to the untreated tissues. L-cysteine (10 nM–1 µM) and NaHS (30 –100 µM) significantly (p < 0.001; n = 12) prevented H₂O₂-induced oxidative damage in a concentration-dependent manner. Furthermore, AP123 (100 nM–1 µM) attenuated oxidative H₂O₂ damage resulted in an approximated 60% reduction in 8-isoprostane levels compared to the tissues treated with H₂O₂ alone. While AOAA (30 µM) and KBA (1 mM) did not affect the L-cysteine evoked attenuation of H₂O₂-induced oxidative stress, KBA reversed the antioxidant responses caused by AP123. Conclusions: In conclusion, various forms of H₂S-releasing compounds and the substrate, L-cysteine, can prevent H₂O₂-induced lipid peroxidation in an isolated bovine retina. Full article

Background: Hydrogen sulfide (H₂S)-releasing compounds can reduce intraocular pressure in normotensive rabbits by increasing aqueous humor (AH) outflow through the trabecular meshwork. In the present study, we investigated the contribution of endogenous H₂S and the role of intramurally generated prostaglandins in the observed increase in AH outflow facility in an ex vivo porcine ocular anterior segment model. Material and Methods: Porcine ocular anterior segment explants were perfused with Dulbecco’s Modified Eagle’s Medium maintained at 37 °C and gassed with 5% CO₂ and 95% air under an elevated pressure of 15 mmHg for four hours. Perfusates from the anterior segment explants were collected and immediately assayed for their H₂S and prostaglandin E₂ content. Results: Elevating perfusion pressure from 7.35 to 15 mm Hg significantly (p < 0.001) increased H₂S concentration in the perfusate from 0.4 ± 0.1 to 67.6 ± 3.6 nM/µg protein. In the presence of an inhibitor of cystathionine ß-synthase/cystathionine γ-lyase, aminooxyacetic acid (AOAA, 30 µM), or an inhibitor of 3-mercaptopyruvate sulfurtransferase, α-ketobutyric acid (KBA, 1 mM), the effects of elevated pressure on H₂S levels in the perfusate was significant (p < 0.001). Furthermore, flurbiprofen (30 µM) and indomethacin (10 µM) attenuated the elevated pressure-induced increase in H₂S levels in the perfusate. Interestingly, elevating perfusion pressure had no significant effect on PGE₂ concentrations in the perfusate. While the inhibition of H₂S biosynthesis by AOAA or KBA did not affect PGE₂ levels in perfusate, flurbiprofen (30 µM) caused a significant (p < 0.05) decrease in the concentration of PGE₂ under conditions of elevated perfusion pressure. Conclusions: We conclude that the elevated perfusion pressure-induced increase in H₂S concentrations depends upon the endogenous biosynthesis of H₂S and intramurally produced prostaglandins in the porcine anterior segment explants. While the concentration of PGE₂ in the perfusate under elevated perfusion pressure was unaffected by pretreatment with inhibitors of H₂S biosynthesis, it was reduced in the presence of an inhibitor of cyclooxygenase. Full article

Present bladder cancer therapies have relatively limited therapeutic impact and account for one of the highest lifetime treatment costs per patient. Therefore, there is an urgent need to explore novel and optimized treatment strategies. The present study investigated the effects of inhibiting endogenous hydrogen sulfide (H₂S) production on bladder cell viability and in vivo tumor progression. We targeted the H₂S-producing enzyme, cystathionine $\gamma$-lyase, in 5637 cells using propargylglycine (H₂S inhibitor) and performed cytofluorimetric analysis to evaluate cell viability. We then tested the efficacy of propargylglycine alone or in combination with gemcitabine (conventional chemotherapy) in an intravesical murine model of bladder cancer. Magnetic resonance imaging and immunohistochemical staining for cell proliferation, apoptosis, immune-cell infiltration, and neovascularization were performed to evaluate tumor response. Compared to control conditions or cohorts, propargylglycine administration significantly attenuated bladder cancer cell viability in vitro (p < 0.0001) and tumor growth (p < 0.002) and invasion in vivo. Furthermore, propargylglycine enhanced the anti-cancer effects of gemcitabine, resulting in tumor regression (p < 0.0001). Moreover, propargylglycine induced cleaved PARP-1-activated apoptosis (p < 0.05), as well as intratumoral CD8⁺ T cell (p < 0.05) and F4/80⁺ macrophage (p < 0.002) infiltration. Propargylglycine also reduced intratumoral neovascularization (p < 0.0001) and cell proliferation (p < 0.0002). Importantly, the pro-apoptotic and anti-neovascularization effects of gemcitabine were enhanced by propargylglycine co-administration. Our findings suggest that inhibition of endogenous H₂S production can be protective against bladder cancer by enhancing the chemotherapeutic action of gemcitabine and may be a novel pharmacological target and approach for improved bladder cancer diagnosis and treatments in the future. Full article

During estrus, the poll glands of male Bactrian Camels (Camelus Bactrianus) become slightly raised, exuding a large amount of pale yellow watery secretion with a characteristic odor that may contain hydrogen sulfide (H₂S). However, whether H₂S can be synthesized in the poll glands of male Bactrian Camels and its role in inducing camel estrus remains unclear. This study aimed to identify differentially expressed proteins (DEPs) and signaling pathways in the poll gland tissues of male Bactrian Camels using data independent acquisition (DIA) proteomics. Additionally, gas chromatography–mass spectrometry (GC-MS) was performed to identify differentially expressed metabolites (DEMs) in the neck hair containing secretions during estrus in male Bactrian Camels, to explore the specific expression patterns and mechanisms in the poll glands of camels during estrus. The results showed that cystathionine-γ-lyase (CTH) and cystathionine-β-synthase (CBS), which are closely related to H₂S synthesis in camel poll glands during estrus, were mainly enriched in glycine, serine, and threonine metabolism, amino acid biosynthesis, and metabolic pathways. In addition, both enzymes were widely distributed and highly expressed in the acinar cells of poll gland tissues in camels during estrus. Meanwhile, the neck hair secretion contains high levels of amino acids, especially glycine, serine, threonine, and cystathionine, which are precursors for H₂S biosynthesis. These results demonstrate that the poll glands of male Bactrian Camels can synthesize and secrete H₂S during estrus. This study provides a basis for exploring the function and mechanism of H₂S in the estrus of Bactrian Camels. Full article

Epidemiological data suggest that moderate hyperoxemia may be associated with an improved outcome after traumatic brain injury. In a prospective, randomized investigation of long-term, resuscitated acute subdural hematoma plus hemorrhagic shock (ASDH + HS) in 14 adult, human-sized pigs, targeted hyperoxemia (200 < P_aO₂ < 250 mmHg vs. normoxemia 80 < P_aO₂ < 120 mmHg) coincided with improved neurological function. Since brain perfusion, oxygenation and metabolism did not differ, this post hoc study analyzed the available material for the effects of targeted hyperoxemia on cerebral tissue markers of oxidative/nitrosative stress (nitrotyrosine expression), blood–brain barrier integrity (extravascular albumin accumulation) and fluid homeostasis (oxytocin, its receptor and the H₂S-producing enzymes cystathionine-β-synthase and cystathionine-γ-lyase). After 2 h of ASDH + HS (0.1 mL/kgBW autologous blood injected into the subdural space and passive removal of 30% of the blood volume), animals were resuscitated for up to 53 h by re-transfusion of shed blood, noradrenaline infusion to maintain cerebral perfusion pressure at baseline levels and hyper-/normoxemia during the first 24 h. Immediate postmortem, bi-hemispheric (i.e., blood-injected and contra-lateral) prefrontal cortex specimens from the base of the sulci underwent immunohistochemistry (% positive tissue staining) analysis of oxidative/nitrosative stress, blood–brain barrier integrity and fluid homeostasis. None of these tissue markers explained any differences in hyperoxemia-related neurological function. Likewise, hyperoxemia exerted no deleterious effects. Full article

YCA1, the only metacaspase in Saccharomyces cerevisiae, plays important roles in the regulation of chronological lifespan, apoptosis, and cytokinesis. YCA1 has protein hydrolase activity and functions by cleaving itself and target proteins. However, there are few reports about the regulation of YCA1 activity. In this study, we observed that reactive sulfane sulfur (RSS) can inhibit the activity of YCA1. In vitro experiments demonstrated that RSS reacted with the Cys₂₇₆ of YCA1, the residue central to its protein hydrolase activity, to form a persulfidation modification (protein-SSH). This modification inhibited both its self-cleavage and the cleavage of its substrate protein, BIR1. To investigate further, we constructed a low-endogenous-RSS mutant of S. cerevisiae, BY4742 Δcys3, in which the RSS-producing enzyme cystathionine-γ-lyase (CYS3) was knocked out. The activity of YCA1 was significantly increased by the deletion of CYS3. Moreover, increased YCA1 activity led to reduced chronological lifespan (CLS) and CLS-driven apoptosis. This study unveils the first endogenous factor that regulates YCA1 activity, introduces a novel mechanism of how yeast cells regulate chronological lifespan, and broadens our understanding of the multifaceted roles played by RSS. Full article

S-allyl-L-cysteine (SAC) is a sulfur compound present in fresh garlic. The reference literature describes its anticancer, antioxidant and neuroprotective effects. Breast cancer is infamously known as one of the most commonly diagnosed malignancies among women worldwide. Its morbidity and mortality make it reasonable to complete and expand knowledge on this cancer’s characteristics. Hydrogen sulfide (H₂S) and its naturally occurring donors are well-known investigation subjects for diverse therapeutic purposes. This study was conducted to investigate the SAC antiproliferative potential and effect on three enzymes involved in H₂S metabolism: 3-mercaptopyruvate sulfurtransferase (MPST), cystathionine γ-lyase (CTH), and cystathionine β-synthase (CBS). We chose the in vitro cellular model of human breast adenocarcinomas: MCF-7 and MDA-MB-231. The expression of enzymes after 2, 4, 6, 8, and 24 h incubation with 2.24 mM, 3.37 mM, and 4.50 mM SAC concentrations was examined. The number of living cells was determined by the MTS assay. Changes in cellular plasma membrane integrity were measured by the LDH test. Expression changes at the protein level were analyzed using Western blot. A significant decrease in viable cells was registered for MCF-7 cells after all incubation times upon 4.50 mM SAC exposure, and after 6 and 24 h only in MDA-MB-231 upon 4.50 mM SAC. In both cell lines, the MPST gene expression significantly increased after the 24 h incubation with 4.50 mM SAC. S-allyl-L-cysteine had opposite effects on changes in CTH and CBS expression in both cell lines. In our research model, we confirmed the antiproliferative potential of SAC and concluded that our studies provided current information about the increase in MPST gene expression mediated by S-allyl-L-cysteine in the adenocarcinoma in vitro cellular model for the MCF-7 and MDA-MB-231 cell lines. Further investigation of this in vitro model can bring useful information regarding sulfur enzyme metabolism of breast adenocarcinoma and regulating its activity and expression (gene silencing) in anticancer therapy. Full article