Characterization of tangeretin as an activator of nuclear factor erythroid 2-related factor 2/antioxidant response element pathway in HEK293T cells.

Numerous studies have reported that tangeretin is a polymethoxylated flavone with a variety of biological activates, but little research has been done on the antioxidant mechanism of tangeretin. Hence, we investigated the effect of tangeretin on the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and its potential molecular mechanisms by in vitro and in silico research. The results of molecular docking suggested that tangeretin bound at the top of the central pore of Kelch-like ECH-associated protein 1 (Keap1) Kelch domain, and the hydrophobic and hydrogen bond interactions contributed to their stable binding. Herein, the regulation of Nrf2-ARE pathway by tangeretin was explored in the human embryonic kidney cell line HEK293T, which is relatively easy to be transfected. Upon binding to tangeretin, Nrf2 translocated to the nucleus of HEK293T cells, which in turn activated the Nrf2-ARE pathway. Luciferase reporter gene analysis showed that tangeretin significantly induced ARE-mediated transcriptional activation. Real-time PCR and Western blot assays showed that tangeretin induced the gene and protein expressions of Nrf2-mediated targets, including heme oxygenase 1 (HO-1), nicotinamide adenine dinucleotide phosphate (NADPH) quinone dehydrogenase 1 (NQO1), and glutamate-cysteine ligase (GCLM). In addition, tangeretin could effectively scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. In summary, tangeretin may be a potential antioxidant via activating the Nrf2-ARE pathway.

Characterization of diphenyl phthalate as an agonist for estrogen receptor: an in vitro and in silico study.

Phthalate esters (PAEs) are important pollutants in the environment, which can interfere with the endocrine system by mimicking estrogen. However, limited information is available on modulating the estrogen receptor (ER) of five PAEs including di (2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), benzyl butyl phthalate (BBP), diphenyl phthalate (DPhP) and dicyclohexyl phthalate (DCHP). This study evaluated the agonistic effects of PAEs on human ER. The cytotoxicity assay showed that there were a significant inhibition of the cell proliferation with treatment of five PAEs. Moreover, DPhP does-dependently enhanced ER-mediated transcriptional activity in the reporter gene assay. The increased expression of estrogen-responsive genes (TFF1, CTSD, and GREB1) was also observed in MCF-7 cells treated with DPhP. The result of molecular docking showed that DPhP tended to bind to the agonist conformation of ER compared with the antagonist conformation of ER, demonstrating its agonist characteristic that has been confirmed in the reporter gene assay. Thus, we found that DPhP may be evaluated as an ER agonist in vitro and it can interfere with the normal function of human ER.

20(S)-Ginsenoside Rg3 Inhibits Lung Cancer Cell Proliferation by Targeting EGFR-Mediated Ras/Raf/MEK/ERK Pathway.

Lung cancer is the leading cause of cancer death in the world and classified into non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). As tyrosine kinase inhibitors (TKIs), several triterpenoid saponins can target to epidermal growth factor receptor (EGFR), a widely used molecular therapeutic target, to exhibit remarkable anti-proliferative activities in cancer cells. As one of triterpenoid saponins, 20([Formula: see text])-ginsenoside Rg3 [20([Formula: see text])-Rg3] was confirmed to be an EGFR-TKI in this work. According to the quantitative real-time reverse transcription-PCR (qRT-PCR) and immunoblotting analysis, 20([Formula: see text])-Rg3 was certified to play a key role on EGFR/Ras/Raf/MEK/ERK signal pathway regulation. Our data demonstrated that 20([Formula: see text])-Rg3 might block the cell cycle at the G0/G1 phase by downregulating CDK2, Cyclin A2, and Cyclin E1. Molecular docking suggested that the combination of both hydrophobic and hydrogen-bonding interactions may help stabilizing the 20([Formula: see text])-Rg3-EGFR binding. Furthermore, their binding stability was assessed by molecular dynamics simulation. Taken together, these data provide the evidence that 20([Formula: see text])-Rg3 could prohibit A549 cell proliferation, probably by arresting the cell cycle at the G0/G1 phase via the EGFR/Ras/Raf/MEK/ERK pathway.

Characterization of ß-Sitosterol for Potential Selective GR Modulation.

BACKGROUND: Although glucocorticoids (GCs) are characterized as powerful agents to treat inflammatory afflictions, they are accompanied by metabolic side effects which limit their usage. ß-Sitosterol, as a minor component found in extraction of vegetable oil, was reported to have anti-inflammatory effects in RAW 264.7 cells. OBJECTIVE: To test whether ß-sitosterol has an effect to dissociate transrepression from transactivation as a selective novel GR binder, this work evaluated the dissociated characteristics of ß-sitosterol. METHODS: The probable binding interaction between ß-sitosterol and GR was explored by molecular docking. The GR transcriptional activity of ß-sitosterol was assessed in the reporter gene assay. The ability of ß-sitosterol to modulate the transactivation and transrepression of GR was evaluated by real-time quantitative PCR analysis. RESULTS AND DISCUSSION: In the present study, ß-sitosterol treatment cannot induce GR-mediated transactivation. ß-Sitosterol exerted a potential to inhibited the expression of GR target transrepressed gene without activating the expression of GR transactivation dependent gene. Molecular docking demonstrated that ß-Sitosterol was able to bind the ligand binding domain of GR but unable to induce GR activation. CONCLUSION: This work offers evidence that ß-sitosterol may serve as a selective GR modulator.

Cucurbitacin IIb induces apoptosis and cell cycle arrest through regulating EGFR/MAPK pathway.

Epidermal growth factor receptor (EGFR) is considered as a valid target in the clinical trials of anticancer therapy and tyrosine kinase inhibitors (TKIs) of EGFR are approved for cancer treatments. In present work, cucurbitacin IIb (CuIIb) was confirmed to exhibit the proliferation inhibitory activity in A549 cells. CuIIb induced apoptosis via STAT3 pathway, which was mitochondria-mediated and caspase-dependent. CuIIb also suppressed the cell cycle and induced G2/M phase cell cycle arrest. CuIIb was capable of suppressing the signal transmitting of the EGFR/mitogen-activated protein kinase (MAPK) pathway which was responsible for the apoptosis and cell cycle arrest. Homogeneous time-resolved fluorescence (HTRF) analysis demonstrated that the kinase activity of EGFR was inhibited by CuIIb. Molecular docking suggested that the CuIIb-EGFR binding fundamentally depends on the contribution of both hydrophobic and hydrogen-bonding interactions. Hence CuIIb may serve as a potential EGFR TKI.

Phthalate esters and dexamethasone synergistically activate glucocorticoid receptor.

This study was conducted to determine the endocrine-disrupting effects of phthalate esters (PAEs) on the glucocorticoid receptor (GR) signaling. Potential (anti)glucocorticoid activities of six typical PAEs including di (2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), diethyl phthalate (DEP) and dimethyl phthalate (DMP) were evaluated on human GR using cell viability assessment, reporter gene expression analysis, mRNA analysis, and molecular docking and simulation. For all tested chemicals, co-treatment of DEHP and DINP with dexamethasone (DEX) exhibited a synergistic effect on GR transactivity in the reporter assays. Such co-treatment also synergistically enhanced DEX-induced upregulation of GR mediated gene (PEPCK, FAS and MKP-1) mRNA expression in HepG2 cells and A549 cells. Molecular docking and dynamics simulations showed that hydrophobic interactions may stabilize the binding between molecules and GR. In summary, DEHP and DINP may be involved in synergistic effects via human GR, which highlight the potential endocrine-disrupting activities of PAEs as contaminants.

Computational and experimental characterization of estrogenic activities of 20(S, R)-protopanaxadiol and 20(S, R)-protopanaxatriol.

BACKGROUND: As the main metabolites of ginsenosides, 20(S, R)-protopanaxadiol [PPD(S, R)] and 20(S, R)-protopanaxatriol [PPT(S, R)] are the structural basis response to a series of pharmacological effects of their parent components. Although the estrogenicity of several ginsenosides has been confirmed, however, the underlying mechanisms of their estrogenic effects are still largely unclear. In this work, PPD(S, R) and PPT(S, R) were assessed for their ability to bind and activate human estrogen receptor α (hERα) by a combination of in vitro and in silico analysis. METHODS: The recombinant hERα ligand-binding domain (hERα-LBD) was expressed in E. coli strain. The direct binding interactions of ginsenosides with hERα-LBD and their ERα agonistic potency were investigated by fluorescence polarization and reporter gene assays, respectively. Then, molecular dynamics simulations were carried out to simulate the binding modes between ginsenosides and hERα-LBD to reveal the structural basis for their agonist activities toward receptor. RESULTS: Fluorescence polarization assay revealed that PPD(S, R) and PPT(S, R) could bind to hERα-LBD with moderate affinities. In the dual luciferase reporter assay using transiently transfected MCF-7 cells, PPD(S, R) and PPT(S, R) acted as agonists of hERα. Molecular docking results showed that these ginsenosides adopted an agonist conformation in the flexible hydrophobic ligand-binding pocket. The stereostructure of C-20 hydroxyl group and the presence of C-6 hydroxyl group exerted significant influence on the hydrogen bond network and steric hindrance, respectively. CONCLUSION: This work may provide insight into the chemical and pharmacological screening of novel therapeutic agents from ginsenosides.

Transcriptional response of Pseudomonas chenduensis strain MBR to cadmium toxicity.

Cadmium (Cd) contamination has resulted in serious environmental pollution and threatens human health and ecosystems. Our recent studies have demonstrated that Pseudomonas chenduensis strain MBR can decrease Cd bio-availability and reduce Cd accumulation in rice; however, the transcriptional mechanisms underlying the bacterial response during and particularly after Cd bioremediation are still unclear. In this study, we used RNA-Seq to investigate the transcriptional profiles of strain MBR during and after Cd bioremediation. During Cd bioremediation, MBR removed all Cd2+ ions in solution within 24 h, accompanied by 564 upregulated and 363 downregulated expressed genes compared with that of the control (without Cd supplementation). Specifically, under Cd stress, the upregulation of czc (czcA, czcB, and czcC) and mer (merA, merT, merC, and merP) genes enabled Cd efflux from the cytoplasm and conferred resistance of MBR to Cd toxicity. The upregulation of genes (algK, algX, and alg44) related to biofilm formation enabled Cd absorption and contributed to Cd bioremediation. After Cd bioremediation, MBR was transferred to non-Cd medium, and the genes related to histidine metabolism and flagellar assembly still showed similar expression patterns as those during bioremediation (defined as Cd legacy effects). However, the genes involved in Cd resistance and bioremediation were not influenced by Cd legacy effects. This study provides new and thorough insights into the molecular mechanisms underlying Cd bioremediation by a functional microbe. KEY POINTS: • The upregulation of czc and mer genes is responsible for MBR resistance to Cd. • The upregulation of genes related to biofilm formation contributes to Cd bioremediation. • Cd effects on genes involved in histidine metabolism and flagellar assembly are long-lasting.

Interactions of bisphenol diglycidyl ethers with estrogen receptors α: Fluorescence polarization, reporter gene, and molecular modeling investigations.

Based on human estrogen receptor α ligand binding domain (hERα-LBD) as recognition element, a fluorescence polarization assay was developed for the determination of bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and their derivatives. Fluorescence polarization assay showed that BADGE, BFDGE and their derivatives exhibited dose-dependent binding to the receptor protein. The results of reporter gene assay indicated that all the tested bisphenol diglycidyl ethers show no agonistic activities, but some of them exhibit anti-estrogenic activities toward ERα. All the tested bisphenol diglycidyl ethers fitted into the hydrophobic binding pocket and adopted the conformation that resembled 4-hydroxytamoxifen, a selective antagonist of ERα. Quantitative structure-activity relationship analysis showed that the binding potencies of bisphenol diglycidyl ethers with hERα-LBD might be structure-dependent. This work may provide insight into the in silico screening of ER ligands from unsuspected chemicals.

Graphene oxide-based colorimetric detection of organophosphorus pesticides via a multi-enzyme cascade reaction.

Size-tunable graphene oxides (GO) were synthesized as a horseradish peroxidase (HRP) mimic for colorimetric detection of organophosphorus pesticides (OPs) at nanomolar levels via a cascade reaction. A GO-based colorimetric method showed high sensitivity and stability toward OPs, which hold great potential in public health applications.

20(S)-Protopanaxadiol blocks cell cycle progression by targeting epidermal growth factor receptor.

20(S)-Protopanaxadiol [20(S)-PPD], one of the metabolites of ginsenosides, was investigated to determine its potential mechanism for targeting to epidermal growth factor receptor (EGFR) pathway in lung cancer cell A549. Results of kinase inhibitory assay showed that 20(S)-PPD was an EGFR tyrosine kinase inhibitor. By binding to EGFR, 20(S)-PPD disrupted the EGFR/MAPK signaling. The expression of genes in the pathway was altered and the upregulation of Ras and MEK1 was extremely notable. The accumulation and phosphorylation of EGFR, Ras, BRAF, Raf-1, MEK, and ERK were variously altered. The above alteration subsequently resulted in cell cycle arrest. 20(S)-PPD interfered the cell cycle regulation network and eventually blocked cell cycle progression at G0/G1 phase, which may be the key reason for proliferation inhibition. Although some apoptosis related genes and proteins were influenced, apoptosis was not the main reason for proliferation inhibition. The cell wound healing assay confirmed that the inhibition of 20(S)-PPD to A549 cells could suppress the migration and invasion thereof. The results of molecular docking and molecular dynamics simulation provide a possible interaction mechanism between EGFR and 20(S)-PPD. The results described above suggested that 20(S)-PPD could block cell cycle progression by targeting the EGFR/MAPK signaling pathway.

Dynamics and potential roles of abundant and rare subcommunities in the bioremediation of cadmium-contaminated paddy soil by Pseudomonas chenduensis.

Microbial bioremediation of heavy metal-contaminated soil is a potential technique to reduce heavy metals in crop plants. However, the dynamics and roles of the local microbiota in bioremediation of heavy metal-contaminated soil following microbial application are rarely reported. In this study, we used Pseudomonas chenduensis strain MBR for bioremediation of Cd-contaminated paddy soil and investigated its effects on the dynamics of the local soil bacterial community and Cd accumulation in rice. Cd accumulation in rice grains and roots were significantly reduced by the addition of the strain MBR. The addition of the strain MBR caused greater changes in bacterial communities in rhizosphere soil than in bulk soil. MBR enhanced the roles of microbial communities in transformation of Cd fractions, especially in rhizosphere soil. The strain MBR likely regulated abundant subcommunities more than rare subcommunities to improve Cd bioremediation, especially in rhizosphere soil. Consequently, the dynamics and functional roles of the local microbial communities differed significantly during bioremediation between abundant and rare subcommunities and between rhizosphere soil and bulk soil. This study provides new insight into the microbiota-related mechanisms underlying bioremediation.

Cucurbitacin IIa interferes with EGFR-MAPK signaling pathway leads to proliferation inhibition in A549 cells.

Cucurbitacin IIa (CuIIa), a tetracyclic triterpenoid harboring anticancer activity, was investigated in A549 cells to reveal its mechanism of targeting on epidermal growth factor receptor (EGFR) signaling pathway. Results showed that CuIIa was capable of inducing apoptosis and cell cycle arrest at G2/M phase. The transcription of EGFR pathway genes and their proteins accumulation was inconsistently influenced by CuIIa. Notably, transcription of Raf1 was significantly upregulated, nevertheless, MEK1 and ERK1 were significantly downregulated. On the other hand, the accumulation of the total and phosphorylated proteins of the most members in EGFR-mitogen-activated protein kinase (MAPK) pathway, as well as CylclinB1 and survivin were also shifted by CuIIa treatment. Remarkably, total MEK remained constant but survivin completely degraded. Moreover, phosphorylated BRAF continuously increased while Raf1 and MEK decreased continuously. CuIIa was further confirmed to be a tyrosine kinase inhibitor (TKI) of EGFR by kinase inhibition assay. The results of molecular simulation showed that the long side chain of CuIIa occupied the binding pocket of EGFR and the ligand was stabilized at the active site of EGFR. In view of the results above, it is suggested that CuIIa inhibits cell proliferation by interfering the EGFR-MAPK signaling pathway.

Identification of 20(R, S)-protopanaxadiol and 20(R, S)-protopanaxatriol for potential selective modulation of glucocorticoid receptor.

Although glucocorticoids (GCs) are widely used as anti-inflammatory drugs, they are often accompanied by adverse effects, which are mainly due to the transactivation of glucocorticoid receptor (GR) target genes. In order to screen novel plant-derived GR ligands (phytocorticoids) capable of separating transrepression from transactivation, this work focuses on the estimation of 20(R, S)-protopanaxadiol [PPD(R, S)] and 20(R, S)-protopanaxatriol [PPT(R, S)] for their dissociated characteristics. The reporter gene assay shows that ginsenosides cannot enhance glucocorticoid-responsive element-driven genes. The cytotoxicity assay shows that PPT(S), PPT(R), and PPD(S) can inhibit cell proliferation while PPD(R) does not suppress cell growth at available concentration. Further analysis of transactivation and transrepression activities indicates that PPD(R) can repress the transcription of GR target transrepressed gene without activating the expression of the GR target transactivated gene. Results of molecular docking suggest that PPD(R) yields more hydrogen bond interactions and a lower binding energy than its counterparts, resulting in tighter binding between PPD(R) and GR. In addition, PPD(R) achieves stability in the pocket after 2 ns, thereby facilitating exerting its regulatory role of GR target genes. By contrast, other ginsenosides fluctuate drastically during the simulations. In conclusion, PPD(R) may serve as a potential selective GR modulator (SEGRM).

Multi-Residue Method for the Analysis of Stilbene Estrogens in Milk.

The rapid analysis of stilbene estrogens is crucially important in the environment, food and health sectors, but quantitation of lower detection limit for stilbene estrogens persists as a severe challenge. We herein described a homologous and sensitive fluorescence polarization (FP) assay based on estrogen receptor α ligand binding domain (ER-LBD) to monitor stilbene estrogens in milk. Under optimal conditions, the half maximal inhibitory concentrations (IC50) of the FP assay were 9.27 nM, 12.94 nM, and 22.38 nM for hexestrol, dienestrol and diethylstilbestrol, respectively. And the corresponding limits of detection (LOD) values were 2.94 nM, 2.89 nM, and 3.12 nM. Finally, the assay was applied to determine the stilbenes in milk samples where the mean recoveries ranged from 95.76% to 112.78% and the coefficients of variation (CV) below 12.00%. Furtherly, we have focused our study on high cross-reactivity phenomena by using two in silico approaches, including molecular docking analysis and topology analysis. Overall, docking results show that several residues in the hydrophobic pocket produce hydrophobic interactions with the tested drug molecules, which contribute to the stability of their binding. In this paper, we conclude that the FP method is suitable for the rapid detection of stilbenes in milk samples, requiring no expensive analytical equipment or time-consuming sample preparation. This work offers a practical approach that applies bioscience technology in food safety testing and improves analytical speed and laboratory efficiency.

Estrogen receptor-based multi-residue screening of bisphenol compounds in urine.

Human exposure to bisphenol compounds (BPs) has been implicated in the development of several chronic diseases. Instead of exploiting the traditional methods for determination of BPs, this work confirms that the human estrogen receptor α ligand binding domain (hERα-LBD) is a powerful recognition element that can be used to monitor multi-residue of BPs in urine samples by fluorescence polarization (FP) assay. Test parameters were optimized for the best performance. Under the optimal conditions, the IC50 values of BPs are in the range of 0.04-1.61 µg mL-1 . Recovery experiments were then performed to assess the accuracy and precision of the established method. The results detected by FP assay show good agreements with that of liquid chromatography-tandem mass spectrometry method with a fit of R2  = 0.9372 and 0.9640 for BPE and BPAP, respectively. A computational methodology, ligand-based pharmacophore model, was also employed to further explore the broad-specific of tested compounds. It was found that the two hydrogen bond acceptor features and one hydrophobic aliphatic feature were essential for the corresponding cross-reactivity results from the FP assay. All these results suggest that the established method can be successfully applied to monitor the occurrence of BPs in urine.

In vitro and in silico perspectives on estrogenicity of tanshinones from Salvia miltiorrhiza.

This work aims to investigate the structure-activity relationship for binding and activation of human estrogen receptor α ligand binding domain (hERα-LBD) with tanshinones by a combination of in vitro and in silico approaches. The recombinant hERα-LBD was expressed in E. coli strain. The direct binding interactions of tanshinones with hERα-LBD and their ERα agonistic potency were investigated by fluorescence polarization (FP) and reporter gene assays, respectively. FP assay suggested that the tested tanshinones can bind to hERα-LBD as affinity ligands. Tanshinones acted as agonists of hERα as demonstrated by transactivation of estrogen response element (ERE) in transiently transfected MCF-7 cells and by molecular docking of these compounds into the hydrophobic binding pocket of hERα-LBD. Interestingly, comparison of the calculated binding energies versus Connolly solvent-excluded volume and experimental binding affinities showed a good correlation. This work may provide insight into chemical and pharmacological characterization of novel bioactive compounds from Salvia miltiorrhiza.

Estrogen receptor-based fluorescence polarization assay for bisphenol analogues and molecular modeling study of their complexation mechanism.

A fluorescence polarization (FP) assay based on estrogen receptor was developed for the determination of bisphenol compounds (BPs). The human estrogen receptor α ligand binding domain (hERα-LBD) and coumestrol were employed as recognition element and fluorescent probe, respectively. Competitive displacement of tracer from receptor suggested that BPs exhibited dose-dependent binding to hERα-LBD. In order to elucidate the structural basis for the interaction between BPs and hERα-LBD, molecular dynamics simulations were performed to explore their complexation mechanism. The docked bisphenol compounds adopted agonist/antagonist conformations with varying positions and orientations in the hydrophobic binding pocket, depending on their structural characteristics of bridging moieties. Interestingly, the calculated binding energies were generally correlated with the experimentally measured affinities, indicating a potential advantage of the molecular modeling approach in predicting the binding potencies of putative ligands. Considering that the real samples may contain more than one BP, the established FP assay can potentially be used as a pre-screening method to determine the total amounts of bisphenol compounds.

Quantitative structure-activity relationship for estrogenic flavonoids from Psoralea corylifolia.

A combination of in vitro and in silico approaches was employed to investigate the estrogenic activities of flavonoid compounds from Psoralea corylifolia. In order to develop fluorescence polarization (FP) assay for flavonoids, a soluble recombinant protein human estrogen receptor α ligand binding domain (hERα-LBD) was produced in Escherichia coli strain. The competition binding experiment was performed by using coumestrol (CS) as a tracer. The result of FP assay suggested that the tested flavonoids can bind to hERα-LBD as affinity ligands, except for corylin. Then, molecular modeling was conducted to explore the binding modes between hERα-LBD and flavonoids. All the tested compounds fit into the hydrophobic binding pocket of hERα-LBD. The hydrophobic and hydrogen-bonding interactions are dominant forces to stabilize the flavonoids-hERα-LBD binding. It can be speculated from molecular docking study that the hydroxyl groups and prenyl group are essential for flavonoid compounds to possess estrogenic activities. Both methylation of hydroxyl group and cyclization of prenyl group significantly diminish the estrogenic potency of flavonoids. Furthermore, quantitative structure-activity relationship (QSAR) analysis was performed by the calculated binding energies of flavonoids coupled with their determined binding affinities. Comparison between the docking scores and the pIC50 values yields an R-squared value of 0.9722, indicating that the estrogenic potency of flavonoids is structure-dependent. In conclusion, molecular docking can potentially be applied for predicting the receptor-binding properties of undescribed compounds based on their molecular structure.

Effects of Pseudomonas chenduensis and biochar on cadmium availability and microbial community in the paddy soil.

The cadmium contamination in the paddy soil results in serious environmental pollutions. In situ soil remediation based on the applications of additives such as functional microorganisms and biochars has gradually attained more attentions. However, how these exogenous additives affect the local microbial communities is less discussed. In this study, a heavy metal resistant bacterium (Pseudomonas chenduensis, strain MBR) and biochar derived from oil palm fibers were separately added into the simulated Cd-contaminated paddy soil to investigate the roles of these additives in the soil remediation and regulating local microbial community. The results showed that compared with control, the addition of the strain MBR and biochar reduced the exchangeable/acid soluble cadmium fraction by 30% and 18%, respectively. Moreover, higher microbial diversity, more deterministic effects and less variation in microbial community were observed in the treatments supplemented with the strain MBR and biochar, and the increase of the deterministic effects on microbial interactions was demonstrated by network analysis further. Additionally, the abundance of the strain MBR in the paddy soil decreased as time passed, which maximally decreased the disturbance for the local micro-ecological niche and ensured ecological security. These results showed that two additives supplementation, in particular Pseudomonas chenduensis, can significantly decrease cadmium availability, contributing to the reduction of the disturbance on soil microbial community and maintaining microbial stability under cadmium pressure. It highlights a new criterion referred to micro-ecology for the evaluation of the roles of additives in local soil remediation.