K+/H+ ionophore; NLRP3

In a dose-dependent way, nigericin (0.1 μM) impeded the growth and colony formation of H460 lung cancer cells. Nigericin prevents H460 lung cancer cells from migrating and from thinning[1]. There appears to be a dual effect of nigericin (0.1–10 nM) on cell volume: a shrinking effect at lower concentrations and a swelling effect at higher ones. At concentrations of 0.1–1 nM, nigerin dramatically lowers cytosolic pH (pHi) and marginally raises PHi at 5 and 10 nM [2]. Nigerin is toxic to S18 and S26 cells, with IC50 values of 2.03±, 0.55 μM, and 4.77±2.35 μM, respectively. In vitro, niridmycin specifically eradicates stem tumors in NPCs. Nirimycin dramatically inhibits S18 and HONE-1 cell migration [3]. HT29 and SW116 cell lines demonstrated fetal toxicity to nigericin, with IC50 values of 12.92±0.25 μMol and 15.86±0.18 μMol, respectively. In typical soft agar assays, nigericin also shows a decreased capacity to form colonies under anchorage-independent circumstances [4].

Volumetric data showed that ngericin (4 mg/kg, ip) exhibited a significant reduction in tumor growth and exhibited good interaction with the chemotherapeutic agent DDP. In vivo, nigericin dramatically lowers Bmi-1. Under nigericin treatment, the CSC content and metastatic potential of NPC cells were partially impacted by overexpression of Bmi-1. The inhibition of nigericin on nasopharyngeal cancer stem cells may be connected to the decline in Bmi-1 [3].

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Nigericin exhibits selective toxicity to CSCs in vivo [3]
To evaluate the in vivo effects of nigericin on NPC cells, nude mice subcutaneously inoculated with S18 and S26 cells, respectively, were randomly divided into four subgroups with treatments of vehicle, DDP, nigericin or the combination of DPP and nigericin, respectively. In the S18 group, nigericin significantly reduced tumor growth and acted synergistically with the chemotherapeutic agent DDP, as shown by the tumor volumes (P < 0.05 or <0.01, Fig. 6A). However, in the S26 group, nigericin only slightly suppressed the growth of S26 xenografts, whereas DDP either alone or in combination with nigericin significantly inhibited the tumor growth (P < 0.05 or <0.01, Fig. 6B). Importantly, each treatment of drugs had effects on the loss of body weights of mice as compared to the control group, with increasing severity ranging from nigericin, DDP to the combination of the two drugs (Fig. 6C).
Immunohistochemistry analysis in S18 xenografts showed the expression of Bmi-1 was lower in the nigericin treated group, suggesting that nigericin could downregulate Bmi-1 in vivo.
Moreover, we assessed the change of PTEN and Snail, two molecules involved in Bmi-1 pathway, after nigericin treatment. As expected, PTEN protein level increased and Snail expression decreased after using nigericin in vivo, as compared to the control groups. These results suggest that downregulation of Bmi-1 might contribute to the inhibited effect of nigericin on NPC CSCs.

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Next, we evaluated the synergistic anti-tumor effect of Nigericin with anti-PD-1 antibody in the 4T1 xenograft model, which included relatively cold tumors and was resistant to immune checkpoint inhibitor treatment due to a lack of T cell infiltration and activation [43,44]. The 4T1 cells were orthotopically transplanted into the mammary fat pad of BALB/c mice. Mice were randomly divided into four groups and treated with the control, nigericin (subcutaneous) or anti-PD-1 antibody (intraperitoneal) alone and together. As expected, PD-1 antibody alone did not show significant anti-tumor effect, whereas nigericin showed moderate anti-tumor effect. The combination of nigericin and anti-PD-1 antibody almost completely suppressed tumor growth (Figure 6B–D). Consistently, the tumor infiltrated CD4+ or CD8+ T cells were increased in the nigericin-treated and combination therapy groups (Figure 6E), suggesting that nigericin-mediated pyroptosis modulated the tumor microenvironment to facilitate the T cell infiltration, thus turning cold tumors into hot tumors. The levels of TNF-α and IFN-γ secreted by CD4+ or CD8+ cells were higher in the nigericin and anti-PD-1 combination therapy groups (Figure 6F and Figure S4C). In accordance with above results, cleaved Caspase-1 and cleaved Caspase-3 also increased in the nigericin-treated group (Figure 6F). In addition, we did not observe that nigericin impacted the expressions of PD-1 or PD-L1 in immune cells and cancer cells (Figure S4D). These data confirmed the synergistic anti-tumor effect of nigericin with anti-PD-1 antibody.
Meanwhile, the systematic side effects of these treatments were assessed in vivo. No noticeable histological toxicity was observed in the tissues from heart, liver, spleen, lung and kidney (Figure S5A). Hematological parameters, including white blood cells, hemoglobin, aspartate aminotransferase, alanine aminotransferase, albumin and creatinine, were in the normal range when treatment was completed (Figure S5B). In conclusion, these results suggested that applying nigericin was an effective strategy for sensitizing TNBCs to immune checkpoint blockage therapy with acceptable systematic side effects. [5]

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nigericin is efficacious in mouse models of USA300 infection [6]
Since the outstanding antibacterial properties of NIG and its efficacy has not been evaluated in animal models of infection, we further tested the in vivo efficacy of NIG using mouse models of S. aureus USA300 infection. We first used deep-seated mouse biofilm infection model with the S. aureus USA300 strain to mimic human deep-seated chronic infections. 5 × 107 CFU of S. aureus USA300 was injected to the thigh of each mouse. Twenty-four hours after bacterial infection, mice were administrated intraperitoneally with 50 mg/kg VAN or 1 mg/kg NIG every 12 hours for 3 days. VAN treatment did not significantly reduce S. aureus USA300 abundance, which suggests the presence of a VAN-tolerant bacterial population in this model ( Figure 3A ). Remarkably, treatment with NIG led to an approximately 103-fold reduction of USA300 load in the infected thigh ( Figure 3A ). The potency of NIG reducing the stationary cells and biofilm populations in vivo was encouraging.

Then, we used a trauma infection model with the S. aureus USA300 strain. Wounds were punched on the back skin of mice, followed by infection with S. aureus USA300. One day after infection, NIG ointment was applied once daily for 9 days. The results showed that NIG reduced USA300 loads approximately 104-fold in the wound ( Figure 3B ). Meanwhile, NIG treatment reduced the wound size by 80% after 10 days, as did mupirocin, an established anti-staphylococcal agent ( Figures 3C, D ), indicating that NIG, as well as mupirocin, may promote wound healing by drastically reducing bacterial load at the site of infection. Through hematoxylin and eosin (H&E) staining of the infected skin, disruption of the skin epidermis layer and infiltration of numerous lymphocytes in the interstitium were observed in the USA300-infected mice, while the mice treated with mupirocin or NIG showed more healed skin structures and decreased lymphocyte levels in the interstitium ( Figure 3E ). Notably, the efficacy of NIG was comparable to that of mupirocin but at an 8,000-fold lower concentration.

A murine model of bloodstream infection was further used. One hour after injection with a lethal dose of USA300 through the tail vein, mice were treated with drugs (via ip) every 12 h for 3 days. Treatment with 1 mg/kg NIG significantly prolonged the survival of USA300-infected mice, which was comparable to that of mice treated with 5 mg/kg VAN ( Figure 3F ). The bacterial loads of USA300 in the heart, liver, spleen, lung and kidney were also detected at 72 h post-infection. NIG treatment led to a 1,000- to 10,000-fold reduction in the bacterial burden in the major organs. The effect of 1 mg/kg NIG was slightly better than that of 2.5 mg/kg VAN ( Figures 3G–K ). These results demonstrate the in vivo efficacy of NIG in the treatment of S. aureus infection.

The K(+),H(+) ionophore and antibiotic nigericin has been shown to trigger apoptosis and is thus considered for the treatment of malignancy. Cellular mechanisms involved include induction of oxidative stress, which is known to activate erythrocytic Ca(2+)-permeable unselective cation channels leading to Ca(2+) entry, increase in cytosolic Ca(2+) activity ([Ca(2+)]i) and subsequent stimulation of eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. This study explored whether and how nigericin induces eryptosis. Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca(2+)]i from Fluo3 fluorescence, pHi from BCECF fluorescence, ceramide abundance utilizing antibodies and reactive oxygen species (ROS) formation from DCFDA-dependent fluorescence. A 48-hr exposure of human erythrocytes to nigericin significantly increased the percentage of annexin-V-binding cells (0.1-10 nM), significantly decreased forward scatter (0.1-1 nM), significantly decreased cytosolic pH (0.1-1 nM) and significantly increased Fluo3 fluorescence (0.1-10 nM). Nigericin (1 nM) slightly, but significantly, increased ROS, but did not significantly modify ceramide abundance. The effect of nigericin on annexin V binding was significantly blunted, but not abolished by removal of extracellular Ca(2+). The nigericin-induced increase in [Ca(2+)]i and annexin V binding was again significantly blunted but not abolished by the Na(+)/H(+) exchanger inhibitor cariporide (10 μM). Nigericin triggers eryptosis, an effect paralleled by ROS formation, in part dependent on stimulation of Ca(2+) entry, and involving the cariporide-sensitive Na(+)/H(+) exchanger[2].

The human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigericin or oxaliplatin under the conditions specified. Cell viability assay and invasion and metastasis assay were performed to evaluate the effect of nigericin on CRC cells. Sphere-forming assay and soft agar colony-forming assay were implemented to assess the action of nigericin on the cancer stem cell properties of CRC cells undergone epithelial-mesenchymal transition (EMT).
Results: Compared with oxaliplatin, nigericin showed more toxicity for the HT29 cell line (IC50, 12.92 ± 0.25 μmol vs 37.68 ± 0.34 μmol). A similar result was also obtained with the SW116 cell line (IC50, 15.86 ± 0.18 μmol vs 41.02 ± 0.23 μmol). A Boyden chamber assay indicated that a significant decrease in the number of HT29 cells migrating through polyvinylidene fluoride membrane was observed in the nigericin-treated group, relative to the vehicle-treated group [11 ± 2 cells per high-power field (HPF) vs 19.33 ± 1.52 cells per HPF, P < 0.05]. Compared to the control group, the numbers of HT29 cells invading through the Matrigel-coated membrane also decreased in the nigericin-treated group (6.66 ± 1.52 cells per HPF vs 14.66 ± 1.52 cells per HPF, P < 0.05). Nigericin also reduced the proportion of CD133+ cells from 83.57% to 63.93%, relative to the control group (P < 0.05). Nigericin decreased the number of spheres relative to the control group (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheres relative to the control group (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). Nigericin also showed a decreased ability to form colonies under anchorage-independent conditions in a standard soft agar assay after 14 d in culture, relative to the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), whereas the colony numbers were higher in the oxaliplatin group relative to the vehicle-treated controls (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further detected the expression of E-cadherin and vimentin in cells treated with nigericin and oxaliplatin. The results showed that HT29 cells treated with nigericin induced an increase in E-cadherin expression and a decrease in the vimentin expression relative to vehicle controls. In contrast, oxaliplatin downregulated the expression of E-cadherin and upregulated the expression of vimentin in HT29 cells relative to vehicle controls.
Conclusion: This study demonstrated that nigericin could partly reverse the EMT process during cell invasion and metastasis[4].

Animal/Disease Models: balb/c (Bagg ALBino) mouse orthotopically injected with 4T1 cells [5]
Doses: 0.025 mg/kg
Route of Administration: subcutaneous injection
Experimental Results: Shown almost complete inhibition of tumor growth with anti-PD-1 antibody.

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Animal/Disease Models: Staphylococcus aureus-infected mice USA300[6]
Doses: 1 mg/kg
Route of Administration: intraperitoneal (ip) injection
Experimental Results: Major The bacterial load in the organs is diminished to 1,000-10,000 times.

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Deep-seated mouse biofilm infection model [6]
A previously reported deep-seated mouse biofilm infection model (Conlon et al., 2013) was used with modifications. 100 μL of stationary-phase S. aureus USA300 (5 × 107 CFU) was injected to the thigh of each mouse. Starting at 24 h post-infection, mice were administrated with 200 µL of nigericin (1 mg/kg, dissolved in 20% (w/v) Kolliphor® HS 15), vancomycin (50 mg/kg), or vehicle intraperitoneally every 12 h for 3 days. Mice were sacrificed 4 days post-infection, and their infected thighs were homogenized, diluted, and plated on MH agar for determination of CFU.

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Murine wound infection [6]
Murine wounds were generated as round lesions having a diameter of 1 cm on the back of each mouse. Each wound was then infected with 10 μL of 3 × 107 CFU/mL S. aureus USA300. Staring at 24 h post-infection, nigericin (0.025 μg per wound) or mupirocin (200 μg per wound), diluted in 0.1% EtOH, was applied to the wounds once daily for 9 days. The wounds were monitored at 1, 5- and 10-days post-infection. The wound tissues were excised and grounded, and aliquots of the grounded tissue were diluted in normal saline and plated on drug-free agar to determine CFU. A portion of the wound tissue was also subjected to hematoxylin and eosin (H&E) staining for histopathological analysis.

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Murine bloodstream infection model [6]
Mice were infected by intravenous injection of 100 μL 1 × 108 CFU/mL S. aureus USA300. Starting at 4 h post-infection, nigericin (0.5, 1 mg/kg, dissolved in 20% (w/v) Kolliphor® HS 15), vancomycin (5 mg/kg), or vehicle (20% (w/v) Kolliphor® HS 15) in a volume of 200 µL was administrated via the intraperitoneal route every 12 h for 3 d. Survival curves were recorded during 3 days of treatment. For determining the bacterial loads of USA300, the mice were sacrificed 3 days post-infection, and their hearts, livers, spleens, lungs, and kidneys were homogenized, diluted, and plated on MH agar for determination of CFU.

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Six-to-eight-week old female immunocompetent BALB/c mice were used. Next, 5 × 105 4T1 cells were injected orthotopically into the left inguinal mammary fat pad of BALB/c mice. Mice were randomly divided into four groups and treated at the same time with indicated drugs. Nigericin (2 mg/kg) was injected subcutaneously every two days, and anti-PD-1 (250 μg/mouse) was injected intraperitoneally every week. Tumor volumes were monitored every three-to-four days. At the end of the experiment (after about 4 weeks), the mice were sacrificed via carbon dioxide euthanasia, and tumors were harvested for further analysis.[5]

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The S18 cells were injected near the scapula of the nude mice. Nine days after injection, the mice were randomly divided into four groups with six animals each (control, DDP, nigericin and DDP combined with nigericin). DDP (2.5 mg/kg) was injected intraperitoneally for five continuous days and nigericin (4 mg/kg) was administrated intraperitoneally every two days. Tumor length and width were measured with a vernier caliper every other day. Tumor volume was calculated using the formula V = 0.5 × (length × width2). The body weights of the mice were recorded every two days. Mice were humanely euthanized when the tumor volume reached 2000 mm3.[3]

The oral LD50 in mice was 190 mg/kg. CRC Handbook of Antibiotic Compounds, Volumes 1-5, Berdy, J., Boca Raton, Florida, CRC Press, 1980, 5(477), 1981. The intraperitoneal LD50 in mice was 2500 μg/kg. Antibiotics and Chemotherapy, 1(594), 1951.

[1]. Nigericin decreases the viability of multidrug-resistant cancer cells and lung tumorspheres and potentiates the effects of cardiac glycosides. Tumour Biol. 2017 Mar;39(3):1010428317694310.

[2]. Triggering of Suicidal Erythrocyte Death by the Antibiotic Ionophore Nigericin. Basic Clin Pharmacol Toxicol. 2016 May;118(5):381-9.

[3]. Nigericin selectively targets cancer stem cells in nasopharyngeal carcinoma. Int J Biochem Cell Biol. 2013 Sep;45(9):1997-2006.

[4]. Suppression of colorectal cancer metastasis by nigericin through inhibition of epithelial-mesenchymal transition. World J Gastroenterol. 2012 Jun 7;18(21):2640-8.

[5]. Nigericin Boosts Anti-Tumor Immune Response via Inducing Pyroptosis in Triple-Negative Breast Cancer. Cancers (Basel). 2023 Jun 16;15(12):3221.

[6]. Nigericin is effective against multidrug resistant gram-positive bacteria, persisters, and biofilms. Front Cell Infect Microbiol. 2022 Dec 20:12:1055929.

Nigericin is a polyether antibiotic that affects ion transport and ATPase activity in mitochondria. It is produced by Streptomyces hygroscopicus. It has multiple functions, including antibacterial, antiviral, potassium ion carrier, and bacterial metabolite activity. (Excerpt from Merck Index, 11th edition) Nigericin has been reported to exist in Streptomyces, Streptomyces violaceus niger, and Streptomyces hygroscopicus, and relevant data are available. (Excerpt from Merck Index, 11th edition)

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Drug resistance in lung cancer is associated with a variety of factors, including tumor heterogeneity and intrinsic or acquired resistance. Enhanced stem cell characteristics and increased cancer cell plasticity have been identified as important mechanisms of resistance; therefore, treatments targeting cancer cells that are independent of stem cell phenotypes will be more effective in lung cancer treatment. In this paper, we investigated the anticancer effects of the antibiotic nigrain in cells with varying degrees of stem cell characteristics and anticancer drug resistance, which were generated under: (1) conventional culture conditions; (2) prolonged serum starvation. These cells were highly resistant to conventional anticancer drugs such as paclitaxel, hydroxyurea, colchicine, oopatakra, vortmannin, and LY294002. The multidrug resistance phenotype of cells grown under prolonged serum starvation conditions may be the result of extensive reprogramming of signaling pathways; (3) lung tumor spheroids rich in cancer stem cell-like cells. We found that nigrain effectively inhibited the viability of cells grown under conventional culture conditions, prolonged serum starvation conditions, and in lung tumor spheroids. In addition, we found that nigrain can downregulate the expression of key proteins in the classical Wnt signaling pathway (such as LRP6, Wnt5a/b and β-catenin), but can promote the translocation of β-catenin to the nucleus. The therapeutic doses of the Wnt activator HLY78 and the FDA-approved drug digoxin and its novel synthetic analog MonoD can enhance the antitumor effect of nigrain. We believe that nigrain can be used in combination with other novel chemotherapy drugs for combination therapy to effectively inhibit cancers with different degrees of stemness and may produce a durable anticancer effect. [1]

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K(+), H(+) ion carriers and antibiotics nigrain have been shown to induce apoptosis and are therefore considered to be used to treat malignant tumors. Its cellular mechanisms include inducing oxidative stress, which is known to activate Ca(2+) permeable nonselective cation channels in erythrocytes, leading to Ca(2+) influx, increased cytoplasmic Ca(2+) activity ([Ca(2+)]i), and subsequently stimulating erythrocyte apoptosis, i.e., erythrocyte suicide death, characterized by cell contraction and translocation of cell membrane phosphatidylserine to the erythrocyte surface. This study investigated whether and how nigericin induces erythrocyte apoptosis. The exposure of phosphatidylserine on the cell surface was measured by annexin V binding, cell volume was measured by forward scattering, intracellular calcium ion concentration [Ca²⁺]i was measured by Fluo3 fluorescence, intracellular pH was measured by BCECF fluorescence, ceramide abundance was measured using antibodies, and reactive oxygen species (ROS) generation was measured by DCFDA-dependent fluorescence. Forty-eight hours after exposure to nigrain, human erythrocytes showed a significant increase in the percentage of annexin V-bound cells (0.1–10 nM), a significant decrease in forward scattering (0.1–1 nM), a significant decrease in cytoplasmic pH (0.1–1 nM), and a significant increase in Fluo3 fluorescence (0.1–10 nM). 1 nM nigrain slightly but significantly increased ROS levels but had no significant effect on ceramide abundance. Removal of extracellular calcium ions significantly weakened, but did not completely eliminate, the effect of nigrain on annexin V binding. The nigrain-induced increase in intracellular calcium concentration [Ca(2+)]i and annexin V binding was again significantly inhibited, but not completely eliminated, by the Na(+)/H(+) exchange inhibitor calipperidone (10 μM). Nigrain-induced erythrocyte apoptosis, an effect accompanied by reactive oxygen species (ROS) generation, was partially dependent on Ca(2+) influx stimulation and involved the calipperidone-sensitive Na(+)/H(+) exchanger. [2] Nasopharyngeal carcinoma (NPC) is common in southern China, North Africa, and Alaska. Early-stage NPC patients have a good prognosis, while late-stage patients have a poor prognosis. Cancer stem cells (CSCs) are considered to be associated with tumor development, recurrence, and metastasis, and the poor prognosis of NPC may be due to residual CSCs after treatment. Although treatment targeting CSCs has received widespread attention in other cancers, research on treatment targeting CSCs in NPC remains insufficient. This study investigated the effects of the antibiotic nigraminin on CSCs using cell lines with varying proportions of cancer stem cells (CSCs) in nasopharyngeal carcinoma cell lines. We found that nigraminin selectively targets CSCs and enhances the sensitivity of nasopharyngeal carcinoma cells to the commonly used clinical drug cisplatin both in vitro and in vivo. In addition, downregulation of polycomb protein Bmi-1 may contribute to the inhibitory effect of nigraminin on CSCs. Furthermore, using an in vitro nasopharyngeal carcinoma cell model, we found that nigraminin significantly reduces the migration and invasion abilities of cells, which are known to be closely related to CSCs. In summary, our results indicate that nigrain can selectively target nasopharyngeal carcinoma stem cells (CSCs) and may be a CSCs-targeting drug awaiting clinical evaluation. [3]

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Objective: To evaluate the effects of nigrain on colorectal cancer and explore its possible mechanism of action. Methods: Human colorectal cancer (CRC) cell lines HT29 and SW480 were treated with nigrain or oxaliplatin under specific conditions. The effects of nigrain on CRC cells were evaluated by cell viability assay, invasion and metastasis assay. The effects of nigrain on the cancer stem cell characteristics of colorectal cancer cells undergoing epithelial-mesenchymal transition (EMT) were evaluated by spheroid formation assay and soft agar colony formation assay. Results: Nigrain was more toxic to the HT29 cell line than oxaliplatin (IC50 values were 12.92 ± 0.25 μmol and 37.68 ± 0.34 μmol, respectively). Similar results were observed in the SW116 cell line (IC50 values were 15.86 ± 0.18 μmol and 41.02 ± 0.23 μmol, respectively). Boyden chamber migration assays showed a significant reduction in the number of HT29 cells that crossed the polyvinylidene fluoride membrane in the nigrain-treated group compared to the carrier control group [11 ± 2 cells/HPF vs 19.33 ± 1.52 cells/HPF, P < 0.05]. The number of HT29 cells that crossed the Matrigel membrane was also reduced in the nigrain-treated group compared to the control group (6.66 ± 1.52 cells/HPF vs 14.66 ± 1.52 cells/HPF, P < 0.05). Furthermore, the percentage of CD133+ cells decreased from 83.57% to 63.93% in the nigrain-treated group compared to the control group (P < 0.05). Compared with the control group, nigrain reduced the number of spheroids (0.14 ± 0.01 vs 0.35 ± 0.01, P < 0.05), while oxaliplatin increased the number of spheroids (0.75 ± 0.02 vs 0.35 ± 0.01; P < 0.05). After 14 days of culture on standard soft agar plates, nigrain also reduced the ability to form colonies under non-anchored conditions compared with the control group (1.66 ± 0.57 vs 7 ± 1.15, P < 0.05), while the number of colonies in the oxaliplatin group was higher than that in the vector control group (14.33 ± 0.57 vs 7 ± 1.15, P < 0.05). We further examined the expression of E-cadherin and vimentin in cells treated with nigrain and oxaliplatin. The results showed that compared with the vector control group, nigrain-treated HT29 cells showed increased E-cadherin expression and decreased vimentin expression. Conversely, compared with the vector control group, oxaliplatin treatment of HT29 cells downregulated E-cadherin expression and upregulated vimentin expression. Conclusion: This study shows that nigrain can partially reverse the EMT process during cell invasion and metastasis. [4]

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Although immune checkpoint inhibitors have improved the clinical prognosis of patients with advanced triple-negative breast cancer (TNBC), their efficacy remains relatively low. Nigrain is an antibiotic derived from Streptomyces hydrophobicus. We found that nigrain induces cell death in TNBC cell lines MDA-MB-231 and 4T1 by inducing simultaneous pyroptosis and apoptosis. Because nigrain promotes potassium efflux, we found that it leads to mitochondrial dysfunction, which in turn leads to the production of mitochondrial reactive oxygen species (ROS) and activates Caspase-1/GSDMD-mediated pyroptosis and Caspase-3-mediated apoptosis in triple-negative breast cancer (TNBC) cells. Notably, nigrain-induced pyroptosis can amplify the antitumor immune response by enhancing the infiltration and antitumor effects of CD4+ and CD8+ T cells. In addition, nigrasin showed synergistic therapeutic effects when used in combination with anti-PD-1 antibodies for the treatment of TNBC. Our study suggests that nigrasin may be a promising antitumor drug, especially when used in combination with immune checkpoint inhibitors for the treatment of advanced TNBC. [5] Multidrug-resistant bacteria (MDRs) pose a significant clinical threat to human health, but the development of antibiotics cannot meet the urgent need for effective drugs, especially those that can kill persistent bacteria and biofilms. This article reports that nigrasin has strong bactericidal activity against a variety of clinically multidrug-resistant Gram-positive bacteria, persistent infecting bacteria and biofilms, with a low incidence of resistance. In addition, nigrasin showed good in vivo efficacy in mouse deep biofilm, mouse skin and bloodstream infection models. For Staphylococcus aureus, nigrasin disrupts ATP production and electron transport chains; cell death is associated with changes in membrane structure and permeability. Obtaining nigrasin-resistant/tolerant mutants requires multiple challenge tests, and no cross-resistance to multiple antimicrobial drugs was observed, which may be due to the unique mechanism of action of nigrasin and the GraSR two-component regulatory system. Therefore, our study suggests that nigrain is a promising antibiotic candidate for the treatment of chronic or recurrent infections caused by Gram-positive bacteria. [6]

C40H67NAO11

746.9432

746.458

C, 64.32; H, 9.04; Na, 3.08; O, 23.56

28643-80-3

Nigericin;28380-24-7

34230

White to off-white solid powder

1.19g/cm3

779.9ºC at 760mmHg

226.9ºC

4.26E-28mmHg at 25°C

Streptomyces, Streptomyces violaceusniger, and Streptomyces hygroscopicus

4.37

3

11

9

51

1230

19

C[C@H]1CC[C@@H](O[C@H]1[C@@H](C)C(=O)[O-])C[C@@H]2C[C@H]([C@H]([C@@]3(O2)[C@@H](C[C@@](O3)(C)[C@H]4CC[C@@](O4)(C)[C@H]5[C@H](C[C@@H](O5)[C@@H]6[C@H](C[C@H]([C@@](O6)(CO)O)C)C)C)C)C)OC.[Na+]

MOYOTUKECQMGHE-PDEFJWSRSA-M

InChI=1S/C40H68O11.Na/c1-21-11-12-28(46-33(21)26(6)36(42)43)17-29-18-30(45-10)27(7)40(48-29)25(5)19-38(9,51-40)32-13-14-37(8,49-32)35-23(3)16-31(47-35)34-22(2)15-24(4)39(44,20-41)50-34;/h21-35,41,44H,11-20H2,1-10H3,(H,42,43);/q;+1/p-1/t21-,22-,23-,24+,25+,26+,27+,28+,29+,30+,31+,32+,33+,34-,35+,37-,38-,39-,40+;/m0./s1

sodium (R)-2-((2R,3S,6R)-6-(((2S,4R,5R,7R,9R,10R)-2-((2S,2'R,3'S,5R,5'R)-5'-((2S,3S,5R,6R)-6-hydroxy-6-(hydroxymethyl)-3,5-dimethyltetrahydro-2H-pyran-2-yl)-2,3'-dimethyloctahydro-[2,2'-bifuran]-5-yl)-9-methoxy-2,4,10-trimethyl-1,6-dioxaspiro[4.5]decan-7-yl)methyl)-3-methyltetrahydro-2H-pyran-2-yl)propanoate

Helixin C; Azalomycin M; Nigericin sodium; Nigericin sodium salt; 28643-80-3; Sodium nigericin; Nigericin (sodium salt); NIGERICIN, MONOSODIUM SALT; Antibiotic K178; UNII-DGN38HI976; Nigericin sodium; Polyetherin A

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Ethanol :≥ 50 mg/mL (~66.94 mM)
DMSO : ~11.76 mg/mL (~15.74 mM )

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.35 mM) (saturation unknown) in 10% EtOH + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear EtOH stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.5 mg/mL (3.35 mM) in 10% EtOH + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear EtOH stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (3.35 mM) (saturation unknown) in 10% EtOH + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear EtOH stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)