Targeting Pyruvate dehydrogenase kinase (PDK) has emerged as one of the potential therapeutic strategies for non-small cell lung carcinoma (NSCLC). 64, a recently reported PDK1 inhibitor derived from 2,2-dichloroacetophenone (DAP), exhibited promising anticancer effects in NSCLC models. Herein, we sought to investigate the mechanism of action of 64 in two NSCLC cell lines, namely, NCI-H1975 and NCI-H1650. We found that 64 induced intrinsic cancer cell apoptosis by releasing cytochrome C (CytC) from mitochondria, leading to caspase-3 and poly (ADP-ribose) polymerase (PARP) cleavage, which was mediated by reactive oxygen species (ROS). Moreover, we have shown that 64 induced mitochondrial membrane potential (MMP) depolarization and AMPK/MAPK activations were also ROS driven. With the aid of sequencing studies and follow-up biochemical evaluations, we found that 64 activated the NF-κB pathway through P38 MAPK, while the combination of P38 MAPK inhibitor SB203580 with 64 diminished such activation. Interestingly, the combined use of 64 and NF-κB inhibitor (JSH-23) increased pro-apoptosis protein (Bax) expression and decreased pro-survival protein (Bcl-2) expression, resulting in enhanced cancer cell apoptosis via JNK pathway. Our results suggested that 64 induces cancer cell apoptosis in NSCLC models through ROS, while NF-κB activation serves as a survival mechanism upon PDK1 inhibition.
Selective inhibition of hexokinase 2 (HK2) represents a promising therapeutic strategy due to the pivotal role of HK2 in the Warburg effect, enhancement of glycolysis and anti-apoptosis via HK2-Voltage-Dependent Anion Channel 1 (VDAC1) protein-protein interaction. Moreover, HK2 initiates glycolysis to generate lactate, hence this central enzyme can be pharmacologically targeted to enhance therapy outcomes. Currently, no HK2 inhibitors (HK2is) exist in the clinic. Herein, we employed GCVec, an artificial intelligence (AI)-based compound-protein interaction (CPI) prediction tool, along with molecular docking, to identify the HK2i, 106. This compound exhibited an IC50 of 0.79 ± 0.07 μM and a consistent Kd of 0.41 ± 0.03 μM against HK2 enzyme. It also apparently blocked HK2-VDAC1 interaction as indicated by the disrupted colocalization of HK2-GFP and VDAC1-mCherry. Furthermore, 106 demonstrated enhanced anticancer efficacy under hypoxia in tumor cells with elevated HIF-1α/HK2 and VDAC1 levels. Compound 106 selectively targeted SW480 colorectal cancer cells with high HK2 expression, achieving a growth inhibition IC50 value of 5.00 ± 0.94 μM. Consistently, knockout of HK2 in these tumor cells significantly rescued the IC50 values and eliminated the glycolytic inhibition induced by 106. We further showed that 106 reduced lactate and ATP levels and induced markers of apoptosis, including increased p-AMPK/AMPK ratio and increased Bax levels, as well as decreased Bcl2 levels. Collectively, our findings highlight the potential of GCVec in identifying 106, a first in class dual-function HK2i which emerges as a promising lead compound for further development into a possible anticancer therapeutic agent.
Alzheimer’s disease (AD) poses one of the most urgent medical challenges in the 21st century as it affects millions of people. Unfortunately, the etiopathogenesis of AD is not yet fully understood and the current pharmacotherapy options are somewhat limited. Here, we report a novel inhibitor, Compound 44, for targeting cholinesterases, amyloid-β (Aβ) aggregation, and glycogen synthase kinase 3β (GSK-3β) simultaneously with the aim of achieving symptomatic relief and disease modification in AD therapy. We found that Compound 44 had good inhibitory effects on all intended targets with IC50s of submicromolar or better, significant neuroprotective effects in cell models, and beneficial improvement of cognitive deficits in the triple transgenic AD (3 × Tg AD) mouse model. Moreover, we showed that Compound 44 acts as an autophagy regulator by inducing nuclear translocation of transcription factor EB through GSK-3β inhibition, enhancing the biogenesis of lysosomes and elevating autophagic flux, thus ameliorating the amyloid burden and tauopathy, as well as mitigating the disease phenotype. Our results suggest that triple-target inhibition via Compound 44 could be a promising strategy that may lead to the development of effective therapeutic approaches for AD.
With the advancements of next-generation sequencing, publicly available pharmacogenomic datasets from cancer cell lines provide a handle for developing predictive models of drug responses and identifying associated biomarkers. However, many currently available predictive models are often just used as black boxes, lacking meaningful biological interpretations. In this study, we made use of open-source drug response data from cancer cell lines, in conjunction with KEGG pathway information, to develop sparse neural networks, K-net, enabling the prediction of drug response in EGFR signaling pathways and the identification of key biomarkers. To explore the rationality of identified biomarkers, we analyzed distribution patterns between drug-resistant and sensitive cell lines and performed simulated perturbation analysis on drug response. We compared K-net with commonly used interpretable algorithms in biomarker identification, such as lasso logistic regression and random forest classifiers. Our results suggested that K-net outperformed other algorithms in identifying key biomarkers linked to osimertinib response, such as KRAS and TP53 mutations, as well as AKT3 overexpression, accurately revealing their associations with osimertinib resistance. Moreover, K-net revealed subtype-specific top biomarkers for osimertinib resistance, with lung adenocarcinoma (LUAD) showing a predisposition to KRAS mutations and small cell lung cancer (SCLC) exhibiting AKT3 overexpression. Our study revealed that K-net was able to precisely identify critical biomarkers linked to drug responses, highlighting the potential to facilitate optimization of cancer treatment strategies.
KRAS Q61H is an aggressive oncogenic driver mutation rendering cancer cells drug resistant to SHP2 inhibitors (SHP2i). Some metastatic and chemoresistant non-small cell lung cancer (NSCLC) cells, exhibit a hybrid metabolic state in which both glycolysis and oxidative phosphorylation (OXPHOS) coexist. Hence, we evaluated the in vitro and in vivo efficacy of a combination of hexokinase 2 (HK2) and pyruvate dehydrogenase (PDH) inhibitors, benserazide (Benz) and CPI-613, respectively, against NSCLC NCI-H460 cells harboring the driver KRAS Q61H mutation. This combination synergistically disrupted the hybrid metabolic state, inhibited NCI-H460 cell proliferation in vitro, and markedly suppressed tumor growth in NCI-H460 cell xenograft model in mice. The molecular basis underlying this antitumor activity was apparently due to suppression of SHP2/SOS1/RAS/MAPK signaling pathways, leading to enhanced apoptosis. Moreover, this drug combination restored the sensitivity to SHP2i. Consistently, SHP2 overexpression in NCI-H460 cells abrogated the antitumor activity of this drug combination. These findings reveal that the combination of Benz and CPI-613 targets the metabolic vulnerability of KRAS Q61H mutant-bearing NSCLC tumors. These results offer a combination therapeutic strategy for the possible treatment of cancer cells displaying a hybrid metabolic state, thereby surmounting chemoresistance.
Acquired resistance to osimertinib (OSI) poses a significant challenge in the treatment of epidermal growth factor receptor mutant non-small cell lung cancer (NSCLC). Although OSI is effective as a first-line salvage therapy in T790M-positive patients following progression on first- or second-generation EGFR-TKIs (erlotinib, gefitinib, and afatinib), the inevitable development of acquired resistance limits its therapeutic efficacy. This study reveals that OSI-resistant (OSIR) NSCLC cells underwent metabolic reprogramming characterized by enhanced glycolysis and upregulation of hexokinase 2 (HK2). We demonstrated that HK2 inhibitor, benserazide, exhibited significant anticancer effects in OSIR cell models and mediated by reactive oxygen species. Our results suggested that HK2 inhibition effectively modulated the enhanced glycolysis, activated the AMPK-mTOR-autophagy axis, and unexpectedly interfered with NF-κB signaling through direct HK2-IKKβ interaction. Excitingly, the protein expression level and activity of pyruvate dehydrogenase kinase 1 (PDK1) in OSIR cells were upregulated upon HK2 inhibition, indicating a pro-survival role. Combined inhibition of HK2 and PDK1 synergistically inhibited the proliferation of OSIR cells and significantly suppressed tumor growth in an OSIR cell xenograft model, outperforming the single use of HK2 inhibitor. This combination successfully rectified aberrant glucose metabolism and enhanced oxidative phosphorylation. Our findings identified HK2 as a crucial mediator in overcoming OSI resistance and suggested that combined inhibition of HK2 and PDK1 could be a promising approach in OSIR NSCLC.
Development of therapeutic options for Alzheimer's disease (AD) faces severe challenges. Only a few new anti-amyloid drugs based on monoclonal antibodies have been approved in recent years. Although the diversity of etiology and complexity of pathology make AD difficult to cure, these offer various molecular targets amenable for pharmaceutical interventions and disease modulation. In this study, we report an orally bioavailable quinolinium small molecule inhibitor, 88, to modulate neuropathologic changes in triple transgenic AD (3 × Tg-AD) mice. We have shown that 88 exhibited decent cerebral exposure, as compared with the forerunner quaternary isoquinolinium compound, 9Q, that we previously developed. In vivo studies revealed that 88 significantly mitigated cognitive deficits in 3 × Tg AD mice and decreased the amyloid burden as well as tau tangles in the hippocampus. Our data indicated that 88 treatments ameliorated the neuroinflammation via inhibiting glial activation and reducing cytokines IL-1β and IL-6. In vitro studies showed that 88 stabilized mitochondria membrane potential (MMP), decreased ROS generation, recovered respiratory function and ATP production in β-amyloid (Aβ)-induced PC12 cell model, suggesting mitigation of mitochondrial dysfunction. Such restored mitochondrial activity reduced the release of cytochrome c, which helped to prevent neuronal apoptosis both in vitro and in vivo. Our findings suggested that 88 could be useful in modulating AD, while the restoration of mitochondria functions and amelioration of neuroinflammation could be promising avenues for disease modulation.
Alzheimer’s disease (AD) is a neurodegenerative disease that affects over 55 million patients worldwide. Most of the approved small-molecule drugs for AD have been designed to tackle a single pathological hallmark, such as cholinergic dysfunction or amyloid toxicity, and thus may not fully address the multifactorial nature of the disease. Inhibition of both cholinesterase and glycogen synthase kinase-3β (GSK-3β) has emerged as a promising strategy to modulate AD. However, the dual inhibition of these two targets posts challenges in molecular design: issues related to target engagements and biopharmaceutical properties in particular must be overcome. In this review, we discuss the physiopathological roles and structures of cholinesterase and GSK-3β as well as recently reported dual-target inhibitors. We critically evaluate the current status of the discovery of dual-target inhibitors of cholinesterase and GSK-3β, and highlight further perspectives.
Multidrug resistance (MDR) frequently occurs during cancer therapy and remains a major obstacle for the cure of most cancers( [1][1], [2][2] ). Drug resistance could exist intrinsically or be acquired by drug treatment( [3][3]–[5][4] ), yet factors that regulate the resistance remain elusive. Here, we show that most anticancer drugs damage neosynthesized proteins prior to reaching their canonic targets and elicit profound cytotoxicity, which is largely compensated by protein damage response (PDR). We demonstrate that the PDR includes damage recognition and clearance that are mainly mediated by ubiquitin and proteasome systems, although some other factors, including cellular ATP levels and proliferation status, are also involved. We show that cancer stem cells (CSCs), which have lower protein synthesis, and drug resistance acquired cells (DRAC), which have higher proteasome activity, are more resistant than other cells. We further demonstrate that ATP promotes protein synthesis and suppresses proteasome activity, thus, increasing mitochondrial ATP production by PDK1 inhibition and using proteasome inhibitor to block protein damage clearance render CSCs and DRACs more vulnerable to anticancer drugs. Thus, patients with drug-resistant cancers and treatment-naïve patients with low ATP levels and/or high proteasome activity can be identified and subtyped, and therapies containing PDK1-I and/or proteasome-I may be effective options for these patients. ### Competing Interest Statement The authors have declared no competing interest. [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #ref-5
Background and purpose: Trichosanthin (TCS) is a plant-based ribosome-inactivating protein exhibiting a range of pharmacological properties, including abortifacient and anticancer. However, the routine clinical use in cancer treatment was hampered by its antigenicity. Hexokinase 2 (HK2) is a pivotal regulator of glycolysis, where aberrant expression is observed in many cancers. This study investigates the anticancer effects and mechanisms of TCS in combination with benserazide (Benz), a HK2 inhibitor, in Hela and SCC25 cancer models. Experimental approach: MTT, colony-formation and cell cycle assays were performed to assess the cytotoxic effects of TCS and Benz in HeLa and SCC25 cells. Seahorse assay, western blotting, flow cytometry analysis and RNA sequencing were employed to investigate the pharmacological effects of the combo treatment. SCC25 cell xenograft mouse model was established for in vivo efficacy study. Key results: Combined use of TCS and Benz exhibited synergistic anticancer effects in both Hela and SCC25 cell models. The observed synergistic effects were attributed to the modulation of glycolysis by targeting HK2, leading to reduced lactate production and increased ROS accumulation which further inhibited colony formation and cell cycle progression, as well as triggered apoptosis. Moreover, this combination effectively inhibited NFκB/ERK signalling pathways, which were found to be significantly activated upon single use of TCS. It was found that the combination significantly suppressed the tumour growth in SCC25 cell xenograft mouse model. Conclusion: Our findings suggested that targeting HK2 and modulating glycolysis may offer a promising avenue for improving the therapeutic outcomes of TCS-based anticancer treatments.
Leucine-rich repeat containing protein 59 (LRRC59), a ribosome binding protein located on the endoplasmic reticulum and the nuclear envelope. Although it has been found in blood plasma and linked to the development of a few cancers, the function of LRRC59 is still largely unknown and there is no systematic investigation on its role in various human cancers. We performed a multi-omics data analysis to investigate the expression of LRRC59 in human tumors and its correlation with clinical prognosis, gene set enrichment, mutation status, and immune infiltration in cancers using the TCGA, GTEx, GEPIA2, HPA, UALCAN, Timer2, GTBAdb, cBioPortal database and R packages. In the majority of TCGA tumors, LRRC59 was expressed significantly differently (up-regulated in 25 and down-regulated in 4 cancer types). High LRRC59 expression has been linked to worse prognosis in several malignancies. In numerous carcinomas, the expression of LRRC59 was associated clinicopathological stages. The LRRC59 regulation network was mainly involved in the pathways related to endoplasmic reticulum homeostatic and cell proliferation. In addition, the expression of LRRC59 is also strongly associated with the immune cell infiltration. LRRC59 could also predicts the response to immunotherapy. LRRC59 is a potential valuable biomarker not only for diagnostic and prognostic, but also for immunotherapy in most cancers.
Trichosanthin (TCS) is a type I ribosome-inactivating protein extracted from the tuberous root of the plant Trichosanthes. TCS shows promising potential in clinical drug abortion, anti-tumor and immunological regulation. However, the molecular mechanisms of its anti-tumor and immune regulation properties are still not well discovered. In the present study, we investigated the anti-tumor activity of TCS in hepatocellular carcinoma (HCC), both in vitro and in vivo. Both HCC cell lines and xenograft tumor tissues showed considerable growth inhibition after they were treated with TCS. TCS provoked caspase-mediated apoptosis in HCC cells and xenograft tumor tissues. The recruitment of CD8+ T cells to HCC tissues and the expression of chemokines, CCL2 and CCL22, were promoted upon TCS treatment. In addition, TCS induced an upregulation of Granzyme B (GrzB), TNF-α and IFN-γ in HCC tissues, which are the major cytotoxic mediators produced by T cells. Furthermore, TCS also resulted in an increase of mannose-6-phosphate receptor (M6PR), the major receptor of GrzB, in HCC tissues. In summary, these results suggest that TCS perhaps increases T-cell immunity via promoting the secretion of chemokines and accelerating the entry of GrzB to HCC cells, which highlights the potential role of TCS in anti-tumor immunotherapy.
Coronavirus disease 2019 (COVID-19) was reported to be associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, and patients present mostly with respiratory symptoms. There have been an increasing number of reports on oral manifestations, and some of these signs are informative in terms of identifying SARS-CoV-2 infection. The goal of present study was to review and synthesize the clinical characteristics and underlying mechanisms of COVID-19 oral manifestations, as well as to evaluate the factors influencing SARS-CoV-2 infectivity, in order to conduct further in-depth investigations and help clinicians diagnose COVID-19 patients exhibiting oral symptoms.
Alzheimer's disease is a rather complex neurodegenerative disease, which is attributed to a combination of multiple factors. Among the many pathological pathways, synaptic dysfunctions, such as synapses loss and deficits in synaptic plasticity, were thought to be strongly associated with cognitive decline. The deficiencies in various sorts of neurotransmissions are responsible for the multifarious neurodegenerative symptoms in Alzheimer's disease, for example, the cholinergic and glutamatergic deficits for cognitive decline, the excitatory and inhibitory neurotransmission dyshomeostasis for synaptic plasticity deficits and epileptiform symptoms, and the monoamine neurotransmission for neuropsychiatric symptoms. Amyloid cascade hypothesis is the most popular pathological theory to explain Alzheimer's disease pathogenesis and attracts considerable attention. Multiple lines of genetic and pathological evidence support the predominant role of amyloid beta in Alzheimer's disease pathology. Neurofibrillary tangles assembled by microtubule-associated protein tau are other important histopathological characteristics in Alzheimer's disease brains. Cascade of tau toxicity was proved to lead to neuron damage, neuroinflammation and oxidative stress in brain. Ageing is the main risk factor of neurodegenerative diseases, and is associated with inflammation, oxidative stress, reduced metabolism, endocrine insufficiencies and organ failures. These aging related risk factors were also proved to be some of the risk factors contributing to Alzheimer's disease. In Alzheimer's disease drug development, many good therapeutic strategies have been investigated in clinical evaluations. However, complex mechanism of Alzheimer's disease and the interplay among different pathological factors call for the come out of all-powerful therapies with multiple curing functions. This review seeks to summarize some of the representative treatments targeting different pathological pathways currently under clinical evaluations. Multi-target therapies as an emerging strategy for Alzheimer's disease treatment will be highlighted.
Alzheimer's disease (AD) is the most common kind of dementia in the aging population leading to great social and financial burdens in many countries around the world. For decades, disease-modifying drug developed using the "one target, one drug" strategy failed to conquer this disease. Recently, we have designed and synthesized 9R, which exhibited dual inhibition of cholinesterase and amyloid beta (A beta) aggregation in vitro. Herein, we evaluated the in vivo efficacy of 9R in a triple transgenic AD (3xTg-AD) mouse model. 3xTg-AD mice (10-month-old) were dosed intraperitoneally with 9R (daily 3, 10 or 30 mg/kg) for a month. Known cholinesterase inhibitor donepezil (0.3 mg/kg) and A beta aggregation inhibitor tramiprosate (30 mg/kg) were used as positive controls. Cognitive performance of the mice was then evaluated by using Morris Water Maze (MWM), Y-maze tasks and Open Field test. The acetylcholine level, degree of A beta deposition, amyloid precursor protein (APP) processing, neuroinflammation, tau deposition and tau hyperphosphorylation in the brains of the 3xTg-AD mice were examined. We have observed that one-month treatment with 9R significantly improved cognitive deficits in 3xTg-AD mice. Moreover, 9R treatment enhanced the brain acetylcholine level and mitigated the amyloid burden, tau hyperphosphorylation and neuroinflammation in the mouse brains. The effects of 9R on APP processing, neuroinflammation, tau hyperphosphorylation and Cdk-p25 action demonstrated its multifunctional role in 3xTg-AD mouse model. Our results suggested that the use of multi-target compound could be a potential approach to treat AD.
Most cancer cells feature an altered glucose metabolism from oxidative phosphorylation to cytoplasmic glycolysis. Pyruvate dehydrogenase kinases (PDKs) and lactate dehydrogenase A (LDHA) play crucial roles in promotion of glycolysis, thus the inhibition of both enzymes is considered a promising strategy for developing of anticancer therapeutics. Herein, we describe the first discovery of series novel dual inhibitors targeting PDKs and LDHA. We identified 6 hits from a library database containing 485465 compounds through a high-throughput virtual screening assay. Hit-to-lead optimization enabled us to discover two compounds, namely 20e and 20k, which inhibited PDKs with IC50 values of 0.8, and 1.6 μM, respectively, and inhibited LDHA with IC50 values of 0.15 and 0.7 μM, respectively. Meanwhile, the two compounds reduced A549 cell proliferation with EC50 values of 13.2, and 15.7 μM. Furthermore, 20e and 20k decreased the lactate formation, and increased oxygen consumption, suggesting the two compounds modulated the glucose metabolic pathways in cancer cells.
With the surge in the cases of Alzheimer's disease (AD) over the years, several targets have been explored to curb the disease. Cholinesterases, namely acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), remain to be the available targets that are amendable to currently approved treatments. In this study, a series of novel compounds based on tramiprosate, a highly specific amyloid beta (A beta) inhibitor, was designed to inhibit AChE, BuChE, and A beta aggregation. In particular, the addition of a pyridinium/isoquinolinium ring to the tramiprosate moiety (to give compounds 3a-j) led to an increase in the binding affinity for the catalytic active site of cholinesterase, which was hampered by the presence of sulfonic acid. Exclusion of the sulfonic acid moiety led to a novel but effective class of cholinesterase inhibitors (9a-w). in vitro A beta aggregation inhibition assay indicated that compounds 3a-j, 9e-f, 9i-l, 9q, 9r, 9u-w, and 12 could inhibit over 10% A beta aggregation at 1 mM concentration. Cholinesterase inhibition assay suggested that compounds 9g, 9h, 9o, and 9q-t exhibit over 70% inhibition on both AChE and BuChE at a concentration of 100 mu M. Amongst the designed molecules, compound 9r (ca 18% at 1 mM) showed comparable inhibitory effect on the inhibition of A beta aggregation with tramiprosate (ca 20% at 1 mM), along with impressive cholinesterase inhibitory potential (AChE IC50 = 13 mu M and BuChE IC50 = 12 mu M), acceptable toxicity and ability to pass through blood brain barrier, which could be used to ameliorate the phenotypes of AD in preclinical models.
Aim: Anion/cation symport across cellular membranes may lead to cell apoptosis and be developed as a strategy for new anticancer drug discovery. Methodology: Four aza-crown ether-squaramide conjugates were synthesized and characterized. Their anion recognition, anion/cation symport, cytotoxicity and probable mechanism of action were investigated in details. Conclusion: These conjugates are able to form ion-pairing complexes with chloride anions and facilitate the transmembrane transport of anions via an anion/cation symport process. They can disrupt the cellular homeostasis of chloride anions and sodium cations and induce the basification of acidic organelles in live cells. These conjugates exhibit moderate cytotoxicity toward the tested cancer cells and trigger cell apoptosis by mediating the influx of chloride anions and sodium cations into live cells.
OBJECTIVES:Drug combination in cancer therapy aims to achieve synergistic therapeutic effect, reduced drug dosage, reduced drug toxicity and minimizes or delays the induction of drug resistance. In the present study, we investigated the anticancer effects of the combination of two metabolic modulators, dichloroacetate (DCA) and bacillus caldovelox arginase (BCA) (or pegyated human arginase (HA)).METHODS:The combination treatments were evaluated in MCF-7 and MDA-MB 231 cells as well as in MDA-MB 231 breast cancer xenograft model.KEY FINDINGS:Dichloroacetate and BCA combination exhibited anti-proliferative effects on MCF-7 cells, which were found to be synergistic. Analysis of the gene expression upon drug treatments revealed that the synergistic anti-proliferative effect on MCF-7 cells was possibly in part due to the activation of the p53 pathway. A similar synergistic anti-proliferative effect was observed in the combined use of DCA and HA on MCF-7 and MDA-MB231 cells, which was due to induction of cell cycle arrest at G2/M phase. Moreover, the combination enhanced anti-tumour activity in a MDA-MB 231 xenograft mouse model.CONCLUSIONS:Our results suggested that dichloroacetate and arginase combination exhibited enhanced anti-cancer effects in preclinical breast cancer models which may offer an additional treatment option for breast cancer.
Using the scalp time-varying network method, the present study is the first to investigate the temporal influence of the reference on N170, a negative event-related potential component (ERP) appeared about 170 ms that is elicited by facial recognition, in the network levels. Two kinds of scalp electroencephalogram (EEG) references, namely, AR (average of all recording channels) and reference electrode standardization technique (REST), were comparatively investigated via the time-varying processing of N170. Results showed that the latency and amplitude of N170 were significantly different between REST and AR, with the former being earlier and smaller. In particular, the information flow from right temporal-parietal P8 to left P7 in the time-varying network was earlier in REST than that in AR, and this phenomenon was reproduced by simulation, in which the performance of REST was closer to the true case at source level. These findings indicate that reference plays a crucial role in ERP data interpretation, and importantly, the newly developed approximate zero-reference REST would be a superior choice for precise evaluation of the scalp spatio-temporal changes relating to various cognitive events.