Management of esophageal cancer in patients with a right aortic arch or double aortic arch: a case series of 34 cases.

BACKGROUND: Few cases describing patients with a right aortic arch (RAA) or double aortic arch (DAA) and esophageal cancer (EC) have been reported. METHODS: We analyzed RAA and DAA cases treated with esophagectomy in our center's database and reported in English-language studies until April 1, 2023. Our study assessed the malformation characteristics and surgical details of EC patients with RAA and DAA. RESULTS: We extracted data of 24 EC patients with RAAs and 10 EC patients with DAAs. In both groups, the patients were more likely to be Japanese and male, to have squamous cell carcinoma and to have tumors located in the upper thoracic esophagus or middle thoracic esophagus. Left thoracotomy was commonly applied for RAA patients. For DAA patients, the proportions of left-sided and right-sided approaches were similar. Esophagectomy under video-assisted thoracoscopic surgery (VATS) in RAA or DAA patients had been performed on a routine basis in recent years. There were two anastomotic leakages in each group. Specifically, Kommerell diverticulum rupture occurred in 1 RAA patient; gastric tube dilation occurred in 1 DAA patient; and recurrent laryngeal nerve (RLN) injury occurred in 2 RAA patients. The postoperative course was uneventful for most patients in both cohorts. CONCLUSIONS: Esophageal carcinoma is rarely seen in patients with an RAA or DAA. To adequately dissect superior mediastinal LNs, an auxiliary incision (such as sternotomy), the left door open method or a preceding cervical procedure should be used appropriately. Esophagectomy, whether via thoracotomy or thoracoscopic surgery, can be performed safely for both RAA and DAA.

Catalytic Atroposelective Synthesis of Axially Chiral Azomethine Imines and Neuroprotective Activity Evaluation.

Azomethine imines, as a prominent class of 1,3-dipolar species, hold great significance and potential in organic and medicinal chemistry. However, the reported synthesis of centrally chiral azomethine imines relies on kinetic resolution, and the construction of axially chiral azomethine imines remains unexplored. Herein, we present the synthesis of axially chiral azomethine imines through copper- or chiral phosphoric acid catalyzed ring-closure reactions of N'-(2-alkynylbenzylidene)hydrazides, showcasing high efficiency, mild conditions, broad substrate scope, and excellent enantioselectivity. Furthermore, the biological evaluation revealed that the synthesized axially chiral azomethine imines effectively protect dorsal root ganglia (DRG) neurons by inhibiting apoptosis induced by oxaliplatin, offering a promising therapeutic approach for chemotherapy-induced peripheral neuropathy (CIPN). Remarkably, the (S)- and (R)-atropisomers displayed distinct neuroprotective activities, underscoring the significance of axial stereochemistry.

Rheumatoid arthritis drug sinomenine induces apoptosis of cervical tumor cells by targeting thioredoxin reductase in vitro and in vivo.

Overexpression of thioredoxin reductase (TrxR) has been linked to tumorigenesis and phenotypic maintenance of malignant tumors. Thus, targeting TrxR with natural molecules is a promising strategy for developing anticancer drugs. Sinomenine is a naturally occurring alkaloid isolated from Sinomenium acutum. The drug, Zhengqing Fengtongning made from sinomenine, has been universally applied in rheumatoid arthritis treatment in China as well as other Asian countries for decades. Recently, increasing evidence indicates that sinomenine appears to be a promising therapeutic agent against various cancer cells. However, the exact mechanism underlying the anticancer activity of sinomenine remains unclear. In this study, we identified sinomenine as a kind of new inhibitor for TrxR. Pharmacological inhibition of TrxR by sinomenine results in the decrease of thiols content, increases the levels of reactive oxygen species, and finally facilitates oxidative stress-mediated cancer cell apoptosis. It is vital that knockdown in TrxR1 by shRNA can increase cell sensitivity to sinomenine. Treatment with sinomenine in vivo leads to a decrease in TrxR activity and tumor growth, and an increase in apoptosis. Our findings provide a novel action mechanism related to sinomenine and presents an insight on how to develop sinomenine as a chemotherapeutic agent for cancer therapy.

Targeting thioredoxin reductase by deoxyelephantopin from Elephantopus scaber triggers cancer cell apoptosis.

Elevated expression of thioredoxin reductase (TrxR) is associated with the tumorigenesis and resistance to cancer chemoradiotherapy, highlighting the potential of TrxR inhibitors as anticancer drugs. Deoxyelephantopin (DET) is the major active ingredient of Elephantopus scaber and reveals potent anticancer activity. However, the potential mechanism of action and the cellular target of DET are still unknown. Here, we found that DET primarily targets the Sec residue of TrxR and irreversibly prohibits enzyme activity. Suppression of TrxR by DET leads to accumulation of reactive oxygen species and dysregulation in intracellular redox balance, eventually inducing cancer cell apoptosis mediated by oxidative stress. Noticeably, down-regulation of TrxR1 by shRNA increases cell sensitivity to DET. Collectively, targeting of TrxR1 by DET uncovers a novel mechanism of action in DET and deepens the understanding of developing DET as a potential chemotherapeutic agent for treating cancers.

(±)-Caryopterisines A and B, dimeric monoterpene alkaloids with unprecedented 6/5/5/5/6 pentacyclic rings scaffold from Caryopteris glutinosa.

(±)-Caryopterisines A (1) and B (2) featuring an unprecedented 6/5/5/5/6 pentacyclic rings system were isolated from Caryopteris glutinosa. The structures were determined by spectroscopic and X-ray crystallographic data analyses as well as theoretical calculations. Chiral HPLC resolution of both racemic 1 and 2 afforded their corresponding enantiotropic enantiomers. A plausible biogenesis for 1 and 2 may be originated from Diels-Alder reaction between pyridine-containing oxerine derivatives. The enantiotropic conversion mechanism of the enantiomers was demonstrated by H-D exchange and 18O incorporation studies. Compounds 1 and 2 showed moderate inhibition of estrogen E2 biosynthesis in human ovarian granulosa-like KGN cells. These two alkaloids reduced kynurenine biosynthesis at moderate level via inhibition of indoleamine 2,3-dioxygenase. Alkaloid 2 exhibited moderate inhibition of the release of interleukin-1ß.

Ferulin C triggers potent PAK1 and p21-mediated anti-tumor effects in breast cancer by inhibiting Tubulin polymerization in vitro and in vivo.

Ferulin C, a natural sesquiterpene coumarin, isolated from the roots of Ferula ferulaeoides (Steud.) Korov, displaying potent antiproliferatory activity against breast cancer cells. This study aimed to elucidate the underlying molecular mechanisms of Ferulin C-induced breast cancer cells death in vitro and in vivo. Ferulin C presented potent antiproliferatory activity against MCF-7 and MDA-MB-231 cells and remarkable tubulin polymerization inhibitory activity (IC50 = 9.2 µM). Meanwhile, we predicted Ferulin C bind to the Colchicine site of tubulin through CETSA assay, molecular docking and molecular dynamics (MD) simulations. In immunofluorescence assay, Ferulin C disturbed the microtubule integrity and structure. Furthermore, Ferulin C stimulated significant cell cycle arrest in the G1/S period via p21Cip1/Waf1 - CDK2 signaling, induced classic cell apoptosis, impaired metastasis via down-regulating Ras-Raf-ERK and AKT-mTOR signaling. Intriguingly, Ferulin C treatment induced autophagy by ULK1 signaling to synergize with the inhibition of proliferation and metastasis. Based upon the RNAseq analysis, PAK1, as a novel essential modulator, was involved in the signaling regulated by Ferulin C -induced α/ß-tubulin depolymerization. Additionally, Ferulin C displayed an acceptable antiproliferatory activity in an MCF-7 xenograft model without inducing obvious weight loss in the Ferulin C treated mice. Summarily, our findings substantiated that Ferulin C was a potent, colchicine site binding microtubule-destabilizing agent with anti-proliferation and anti-metastasis activity via PAK1 and p21-mediated signaling in breast cancer cells.

Structurally diverse sesquiterpenoids from the aerial parts of Artemisia annua (Qinghao) and their striking systemically anti-inflammatory activities.

Thirteen new sesquiterpenoids, arteannoides F-R (1-13), along with 13 known analogues (14-26), were isolated from the dried aerial parts of Artemisia annua L. Their structures, including absolute configurations, were unambiguously determined by a combination of physical data analyses (HRESIMS, 1D and 2D NMR, and ECD) as well as the crystal structures of 1, 5, 6, 15, 19, and 23. Among the isolated compounds, 1 features an unusual 11-oxatricyclo[6.2.1.04,9]undecan-2-ene ring system, 5 possesses an uncommon 4,11-ether bridged tricyclic framework, whereas 6 is a new eudesmane-type sesquiterpenoid formed via rearrangement of its carbon backbone. The systemically anti-inflammatory activities of all isolates were evaluated by measuring their inhibitory effects on PGE2, NO, TNF-α, and IL-6 production in LPS-stimulated RAW 264.7 macrophages. Moreover, the structure activity relationships of some compounds are summarized, this study will provide new structural templates for discovering potential anti-inflammatory agents.

Discovery of novel ATAD2 bromodomain inhibitors that trigger apoptosis and autophagy in breast cells by structure-based virtual screening.

ATAD2 has been reported to play an important role in the processes of numerous cancers and validated to be a potential therapeutic target. This work is to discover potent ATAD2 inhibitors and elucidate the underlying mechanisms in breast cancer. A novel ATAD2 bromodomain inhibitor (AM879) was discovered by combining structure-based virtual screening with biochemical analyses. AM879 presents potent inhibitory activity towards ATAD2 bromodomain (IC50 = 3565 nM), presenting no inhibitory activity against BRD2-4. Moreover, AM879 inhibited MDA-MB-231 cells proliferation with IC50 value of 2.43 µM, suppressed the expression of c-Myc, and induced significant apoptosis. Additionally, AM978 could induce autophagy via PI3K-AKT-mTOR signalling in MDA-MB-231 cells. This study demonstrates the development of potent ATAD2 inhibitors with novel scaffolds for breast cancer therapy.

New phenylpropanoid allopyranosides from the rhizomes of Cimicifuga dahurica.

Five new phenylpropanoid allopyranosides (1-5), along with five known compounds (6-10) were isolated from the rhizomes of Cimicifuga dahurica. Their structures were established by means of spectroscopic analyses and chemical methods, as well as comparison with literatures. The anti-inflammatory activities of all isolates were evaluated. Compounds 6, 9 and 10 exhibited inhibitory effects on PGE2 production in LPS stimulated RAW 264.7 macrophages with IC50 values of 19.72, 6.33 and 39.90 µM, respectively.

Computational study on the unbinding pathways of B-RAF inhibitors and its implication for the difference of residence time: insight from random acceleration and steered molecular dynamics simulations.

B-RAF kinase is a clinically validated target implicated in melanoma and advanced renal cell carcinoma (RCC). PLX4720 and TAK-632 are promising inhibitors against B-RAF with different dissociation rate constants (k(off)), but the specific mechanism that determines the difference of their dissociation rates remains unclear. In order to understand the kinetically different behaviors of these two inhibitors, their unbinding pathways were explored by random acceleration and steered molecular dynamics simulations. The random acceleration molecular dynamics (RAMD) simulations show that PLX4720 dissociates along the ATP-channel, while TAK-632 dissociates along either the ATP-channel or the allosteric-channel. The steered molecular dynamics (SMD) simulations reveal that TAK-632 is more favorable to escape from the binding pocket through the ATP-channel rather than the allosteric-channel. The PMF calculations suggest that TAK-632 presents longer residence time, which is in qualitative agreement with the experimental k(off)(k(off) = 3.3 × 10(-2) s(-1) and ΔG(off) = -82.17 ± 0.29 kcal mol(-1) for PLX4720; k(off) = 1.9 × 10(-5) s(-1) and ΔG(off) = -39.73 ± 0.79 kcal mol(-1) for PLX4720). Furthermore, the binding free decomposition by MM/GBSA illustrates that the residues K36, E54, V57, L58, L120, I125, H127, G146 and D147 located around the allosteric binding pocket play important roles in determining the longer residence time of TAK-632 by forming stronger hydrogen bond and hydrophobic interactions. Our simulations provide valuable information to design selective B-RAF inhibitors with long residence time in the future.

Discovery of an EP300 Inhibitor using Structure-based Virtual Screening and Bioactivity Evaluation.

BACKGROUND: EP300 (E1A binding protein p300) played a significant role in serial diseases such as cancer, neurodegenerative disease. Therefore, it became a significant target. METHODS: Targeting EP300 discovery of a novel drug to alleviate these diseases. In this paper, 17 candidate compounds were obtained using a structure-based virtual screening approach, 4449-0460, with an IC50 of 5.89 ± 2.08 uM, which was identified by the EP300 bioactivity test. 4449-0460 consisted of three rings. The middle benzene ring connected the 5-ethylideneimidazolidine-2,4-dione group and the 3-F-Phenylmethoxy group. RESULTS: Furthermore, the interaction mechanism between 4449-0460 and EP300 was explored by combining molecular dynamics (MD) simulations and binding free energy calculation methods. CONCLUSION: The binding free energy of EP300 with 4449-0460 was -10.93 kcal/mol, and mainly came from the nonpolar energy term (ΔGnonpolar). Pro1074, Phe1075, Val1079, Leu1084, and Val1138 were the key residues in EP300/4449-0460 binding with more -1 kcal/mol energy contribution. 4449-0460 was a promising inhibitor targeting EP300, which had implications for the development of drugs for EP300-related diseases.

Design, synthesis and biological evaluation of novel SIRT3 inhibitors targeting both NAD+ and substrate binding sites for the treatment of acute myeloid leukemia.

Acute myeloid leukemia (AML) represents a highly malignant subtype of leukemia with limited therapeutic options. In this study, we propose a novel therapeutic strategy for treating AML by inhibiting SIRT3 to regulate mitochondrial metabolism network involved in energy metabolism and epigenetic modifications essential for AML survival. A series of thieno [3,2-d]pyrimidine-6-carboxamide derivatives were designed and synthesized by structure-based strategy, 17f was documented to be a potent and acceptable selective SIRT3 inhibitor with IC50 value of 0.043 µM and exhibited profound anti-proliferative activity in MOLM13, MV4-11, and HL-60 cells. Through CETSA assay and the degree of deacetylation of intracellular SIRT3 substrates, we confirmed that 17f could effectively bind and inhibit SIRT3 activity in AML cells. Mechanistically, 17f suppressed mitochondrial function, triggered the accumulation of ROS, and significantly inhibited the production of ATP in AML cells. With the breakdown of mitochondrial function, 17f eventually induced apoptosis of AML cells. In addition, 17f also showed excellent anti-AML potential in nude mouse tumor models of HL-60-Luc. Collectively, these results demonstrate that 17f is a potent and acceptable selective SIRT3 inhibitor with promising potential to treat AML.

Preoperative camrelizumab combined with chemotherapy for borderline resectable ESCC: A single-arm, prospective, phase 2 study.

BACKGROUND: We investigated the safety and efficacy of preoperative camrelizumab combined with chemotherapy for treating thoracic borderline resectable esophageal squamous cell carcinoma (Br-ESCC) (ChiCTR2200056728). METHODS: Patients with thoracic Br-ESCC received intravenous camrelizumab plus chemotherapy and underwent esophagectomy. The primary endpoint was the pathologic complete response (pCR) rate. We introduced computed tomography and endoscopic examination into the diagnostic criteria to increase its reproducibility. Additionally, we defined a new resection status, Rbr+/-, for Br-ESCC. FINDINGS: Thirty-one patients with Br-ESCC were ultimately enrolled in this study. Overall, 71.0% (22/31) of the patients underwent esophagectomy. R0 resection was achieved in 81.8% of patients (18/22). pCR and major pathological response were observed in 40.9% (9/22) and 63.6% (14/22) of the resected patients, respectively. Eighteen R0 resection patients were redefined according to our Rbr definition; 61.1% (11/18) were classified as Rbr+ resection, and 38.9% (7/18) were classified as Rbr- resection. With a median postoperative follow-up of 17.9 months, 4 patients out of 11 who underwent Rbr+ resection experienced local recurrence (2 of whom achieved pCR). However, no patients (0/7) who underwent Rbr- resection experienced local recurrence. CONCLUSIONS: Esophagectomy after neoadjuvant immunochemotherapy is a promising radical treatment for Br-ESCC. R0 resection was achieved in 81.8% of patients, and a pCR was observed in 40.9% of resected patients. Even after complete excision, Rbr+ resection leads to a higher rate of local recurrence in patients with Br-ESCC. FUNDING: This study was supported by the Key Scientific Research Projects of the Institutions of Higher Learning in Henan Province (no. 21A320032).

An integrated strategy for reducing anastomotic leakage in patients undergoing McKeown esophagectomy.

Objective: To describe our experience of reducing anastomotic leakage, a problem that has not been properly solved. Methods: Starting in January 2020, we began implementing our integrated strategy (application of an esophageal diameter-approximated slender gastric tube, preservation of the fibrous tissue around the residual esophagus and thyroid inferior pole anastomosis) in consecutive patients undergoing esophagectomy without a nasogastric tube or a nasal-jejunum feeding tube. Additionally, the blood supply at the site of the anastomosis was evaluated with a near-infrared fluorescence thoracoscope after the completion of esophagogastric anastomosis in the integrated strategy group. Results: Of 570 patients who were reviewed, 119 (20.9%) underwent the integrated strategy, and 451 (79.1%) underwent the conventional strategy. The rate of anastomotic leakage was 2.5% in the integrated strategy group and 10.2% in the conventional strategy group (p = 0.008). In the integrated strategy group, the site of most of the anastomotic blood supply was the residual esophagus dominant (82.4%), followed by the gastroesophageal dual-dominant (12.6%) and the gastric tube dominant (5.0%). The reconstruction route was more likely to be orthotopic in the integrated strategy group than in the conventional strategy group (89.9% vs. 38.6%, p = 0.004). Gastric dilation was identified in 3.4% of the patients in the integrated strategy group and in 21.1% in the conventional strategy group. Conclusions: Patients who underwent our proposed integrated strategy (Zhengzhou Strategy) during McKeown esophagectomy without a nasogastric tube or a nasal-jejunum feeding tube had a strikingly lower rate of anastomotic leakage and a relatively lower rate of postoperative complications, such as gastric tube dilation and delayed gastric emptying.

Understanding the drug resistance mechanism of hepatitis C virus NS3/4A to ITMN-191 due to R155K, A156V, D168A/E mutations: a computational study.

BACKGROUND: ITMN-191 (RG7227, Danoprevir), as a potential inhibitor of the NS3/4A protease of hepatitis C virus, has been in phase 2 clinical trial. Unfortunately, several ITMN-191 resistance mutants including R155K, A156V, and D168A/E have been identified. METHODS: Molecular dynamics simulation, binding free energy calculation and per-residue energy decomposition were employed to explore the binding and resistance mechanism of hepatitis C virus NS3/4A protease to ITMN-191. RESULTS: Based on molecular dynamics simulation and per-residue energy decomposition, the nonpolar energy term was found to be the driving force for ITMN-191 binding. For the studied R155K, A156V, D168A/E mutants, the origin of resistance is mainly from the conformational changes of the S4 and extended S2 binding pocket induced by the studied mutants and further leading to the reduced binding ability to the extended P2 and P4 moieties of ITMN-191. CONCLUSIONS: Further structural analysis indicates that the destruction of conservative salt bridges between residues 168 and 155 should be responsible for the large conformation changes of the binding pocket in R155K and D168A/E mutants. For A156V mutation, the occurrence of drug resistance is mainly from the changed binding pocket by a replacement of one bulky residue Val. GENERAL SIGNIFICANCE: The obtained drug resistance mechanism of this study will provide useful guidance for the development of new and effective HCV NS3/4A inhibitors with low resistance.

Two new diterpenoids from the rhizomes of Zingiber officinale.

Two undescribed labdane diterpenoids (5S,8S,9R,10S,11E)-8,17-epoxy-13,14-dinorlabd-11-en-13-one (1) and (5S,9R,10S,12E)-17-hydroxy-labd-7,12-dien-15(16)-olide (2), together with seven known sesquiterpenoids (3-9) and two known monoterpenoids (10-11) were isolated from the dried rhizome of Zingiber officinale. Their structures were elucidated by detailed spectroscopic data (IR, UV, HR-ESI-MS, 1D and 2D NMR), X-ray crystallographic and ECD analysis. Moreover, all the 11 compounds were tested for α-glucosidase inhibitory effects and 9 was found to exhibit stronger inhibitory effects at IC50 = 4.8 µM against a positive control acarbose with IC50 = 414.6 µM.

Eremophilane and cadinane sesquiterpenoids from the fruits of Alpinia oxyphylla and their anti-inflammatory activities.

The fruits of Alpinia oxyphylla have been used for centuries in China as both edible resources and traditional Chinese medicine. In order to identify structurally interesting and bioactive constituents from the fruits of A. oxyphylla, bioassay-guided fractionation and purification of the crude extracts were performed, which led to the isolation of 38 sesquiterpenoids, including six previously undescribed eremophilane sesquiterpenoids (1-6), six new cadinane sesquiterpenoids (23-24, 26-29), and 26 known analogues (7-22, 25 and 31-38). The structures of these compounds were elucidated by comprehensive spectroscopic data analysis, single crystal X-ray diffraction, quantum chemistry calculations (13C-NMR and ECD), and Mo2(OAc)4 reaction. Several of the isolated compounds (8, 13, 17, 18, 30, 31 and 35) showed moderate to strong inhibition of the secretion of cytokines (NO, TNF-α and IL-6) in LPS-stimulated BV-2 cells. Furthermore, western blot, immunofluorescence, and real-time PCR assays indicated that 18 could down-regulate the mRNA levels of TNF-α, IL-6, COX-2, and iNOS and the protein expression of COX-2 and iNOS. Meanwhile, 18 was able to partially inhibit the phosphorylation of ERK1/2, JNK, and p38. Thus, the discovery of structurally diverse anti-inflammatory sesquiterpenoids from the fruits of A. oxyphylla in this study could benefit the further development and utilization of this plant.

Identifying the molecular basis of Jinhong tablets against chronic superficial gastritis via chemical profile identification and symptom-guided network pharmacology analysis.

Chronic superficial gastritis (CSG) is a common disease of the digestive system that possesses a serious pathogenesis. Jinhong tablet (JHT), a traditional Chinese medicine (TCM) prescription, exerts therapeutic effects against CSG. However, the molecular basis of its therapeutic effect has not been clarified. Herein, we employed ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) based chemical profile identification to determine the chemical components in JHT. Further, we applied network pharmacology to illustrate its molecular mechanisms. A total of 96 chemical constituents were identified in JHT, 31 of which were confirmed using reference standards. Based on the bioinformatics analysis using the symptom-guided pharmacological networks of "chi," "blood," "pain," and "inflammation," and target screening through the interaction probabilities between compounds and targets, matrix metalloproteinase 2 (MMP2), dopamine d2 receptor (DRD2), and Aldo-keto reductase family 1 member B1 (AKR1B1) were identified as key targets in the therapeutic effect exhibited by JHT against CSG. Moreover, according to the inhibitory activities presented in the literature and binding mode analysis, the structural types of alkaloids, flavonoids, organic acids, including chlorogenic acid (10), caffeic acid (13), (-)-corydalmine (33), (-)-isocorypalmine (36), isochlorogenic acid C (38), isochlorogenic acid A (41), quercetin-3-O-α-l-rhamnoside (42), isochlorogenic acid B (47), quercetin (63), and kaempferol (70) tended to show remarkable activities against CSG. Owing to the above findings, we systematically identified the chemical components of JHT and revealed its molecular mechanisms based on the symptoms associated with CSG.

Oridonin Induces Oxidative Stress-mediated Cancer Cells Apoptosis via Targeting Thioredoxin Reductase.

BACKGROUND: Thioredoxin reductase (TrxR) plays vital role in regulating cellular redox balance as well as redox-mediated signal transduction. Accumulating evidence supports that overactivation of TrxR is closely related to tumorigenesis and that targeting TrxR ablation reverses the growth of numerous malignant tumors, making TrxR a promising target for cancer chemotherapy. Thus, the discovery and development of molecules as promising anticancer agents that target TrxR is of great significance. Oridonin was shown to inhibit TrxR activity, but the detailed cellular mechanism is largely unknown. OBJECTIVE: The study investigated the mechanism of action and underlying inhibitory properties of oridonin on TrxR in HeLa cells. METHODS: A covalent docking was performed to reveal the possible interaction between oridonin and TrxR by Schrödinger Software Suite. TrxR activity was determined by 5,5'-dithiobis-2- nitrobenzoic acid reduction assay and endpoint insulin reduction assay. Sulforhodamine B and colony formation assay were employed to assess the viability and growth of cells. Reactive oxygen species level was measured by probe 2', 7'-dichlorfluorescein diacetate, and dihydroethidium. Hoechst 33342 staining, caspase 3 activation, and fluorescein-5-isothiocyanate-conjugated Annexin V and propidium iodide double staining were used to evaluate apoptosis. RESULTS: Here, we reported the oridonin as a potent inhibitor of TrxR. Inhibition of TrxR results in a decrease of thiols content and total glutathione, elevates reactive oxygen species levels, and finally promotes oxidative stress-mediated apoptosis of cancer cells. CONCLUSION: Targeting TrxR by oridonin discloses a novel molecular mechanism underlying the biological action of oridonin and sheds light on developing oridonin as a potential tumor therapeutic agent.