Terahertz technology and its applications in head and neck diseases.

The terahertz (THz) radiation refers to electromagnetic waves between infrared and millimeter waves. THz technology has shown a significant potential for medical diagnosis and biomedical applications over the past three decades. Therefore, exploring the biological effects of THz waves has become an important new field in life sciences. Specifically, THz radiation has been proved to be able to diagnose and treat several head and neck diseases. In this review, we primarily discuss the biological characteristics of THz waves and clinical applications of THz technology, focusing on the research progress of THz technology in head and neck diseases (brain cancer, hypopharyngeal cancer, oral diseases, thyroid nodules, Alzheimer's disease, eyes diseases, and otitis). The future application perspectives of THz technologies in head and neck diseases are also highlighted and proposed.

Molecular mechanisms of Huanglian Jiedu decoction in treating Alzheimer's disease by regulating microbiome via network pharmacology and molecular docking analysis.

Background: Huanglian Jiedu decoction (HLJDD) is a famous traditional Chinese medicine prescription, which is widely used in the treatment of Alzheimer's disease (AD). However, the interaction between bioactive substances in HLJDD and AD-related targets has not been well elucidated. Aim: A network pharmacology-based approach combined with molecular docking was performed to determine the bioactives, key targets, and potential pharmacological mechanism of HLJDD against AD, through the regulation of microbial flora. Materials and methods: Bioactives and potential targets of HLJDD, as well as AD-related targets, were retrieved from Traditional Chinese Medicine Systems Pharmacology Analysis Database (TCMSP). Key bioactive components, potential targets, and signaling pathways were obtained through bioinformatics analysis, including protein-protein interaction (PPI), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Subsequently, molecular docking was performed to predict the binding of active compounds with core targets. Results: 102 bioactive ingredients of HLJDD and 76 HLJDD-AD-related targets were screened. Bioinformatics analysis revealed that kaempferol, wogonin, beta-sitosterol, baicalein, acacetin, isocorypalmine, (S)-canadine, (R)-canadine may be potential candidate agents. AKT1, TNF, TP53, VEGFA, FOS, PTGS2, MMP9 and CASP3 could become potential therapeutic targets. 15 important signaling pathways including the cancer pathway, VEGF signaling pathway, and NF-κB signaling pathway might play an important role in HLJDD against AD. Moreover, molecular docking analysis suggested that kaempferol, wogonin, beta-sitosterol, baicalein, acacetin, isocorypalmine, (S)-canadine, and (R)-canadine combined well with AKT1, TNF, TP53, VEGFA, FOS, PTGS2, MMP9, CASP3, respectively. Conclusion: Our results comprehensively illustrated the bioactives, potential targets, and possible molecular mechanisms of HLJDD against AD. HLJDD may regulate the microbiota flora homeostasis to treat AD through multiple targets and multiple pathways. It also provided a promising strategy for the use of traditional Chinese medicine in treating human diseases.

Therapeutic potentials of modulating autophagy in pathological cardiac hypertrophy.

Cardiac hypertrophy is an adaptive response to increased overload, which is induced by various physiological or pathological stimuli. It is a common pathological process of a variety of cardiovascular diseases, which eventually leads to heart failure. The development of cardiac hypertrophy is accompanied by anomalous expression of genes such as autophagy-related (Atg) genes and abnormal activation of a series of signaling pathways. Autophagy, with a typical feature of double-membrane vesicle called the autophagosome, is a highly conserved lysosomal degradation process. Autophagosomes engulf cytoplasmic components and deliver them to lysosomes, which degrade cytoplasmic components such as damaged organelles, misfolded proteins to maintain cellular homeostasis and energy supply. Several lines of evidence suggested that autophagy as a double-edged sword was not only involved in physiological cardiac hypertrophy, but played a crucial role in pathological cardiac hypertrophy. However, the exact mechanism underlying the role of autophagy in regulating cardiac hypertrophy remains largely unknown. Here, we comprehensively characterize the dual effects of autophagy in promoting or inhibiting cardiac hypertrophy under a variety of physiological or pathological conditions. Moreover, we summarize the potential therapeutic effects of autophagic modulators on pathological cardiac hypertrophy. Finally, we discuss the advantages and challenges of autophagic modulators for the therapy of pathological cardiac hypertrophy.

Erratum: Microenvironment Activatable Nanoprodrug Based on Gripper-like Cyclic Phenylboronic Acid to Precisely and Effectively Alleviate Drug-induced Hepatitis: Erratum.

[This corrects the article DOI: 10.7150/thno.61214.].

Influence of HNF4α and HNF4α-AS1 gene variants on the risk of anti-tuberculosis drugs-induced hepatotoxicity.

BACKGROUND: The most serious and common complication of the medication recommended by World Health Organization (WHO) for tuberculosis (TB) is anti-tuberculosis drugs-induced hepatotoxicity (ATDH). Pregnane X receptor (PXR) is a key factor of ATDH, while Hepatocyte nuclear factor 4α (HNF4α) and hepatocyte nuclear factor 4 alpha-antisense-1 (HNF4α-AS1) may have co-regulating relationship with PXR. This study aimed to explore whether the genetic variants of HNF4α and HNF4α-AS1 are associated with the predisposition of ATDH. METHODS: TB patients diagnosed in West China Hospital between December 2014 and April 2018 were enrolled. TagSNPs in HNF4α and HNF4α-AS1 gene from the samples of the patients were genotyped with a custom-designed 2×48-plex SNP ScanTM Kit. The frequencies of the alleles, genotypes, genetic models and haplotype distribution of the variants were compared between the case and control groups. The association between SNP and ATDH risk was assessed by single factor logistic regression. RESULTS: Logistic regression analysis showed that none of the 15 genetic variants in HNF4α and HNF4α-AS1 genes were significantly associated with susceptibility to ATDH in the Chinese Han population after Bonferroni correction. CONCLUSIONS: A challenge has arisen to the promising application of SNPs in the HNF4α and HNF4α-AS1 genes as genetic markers for ATDH, and further study is needed with a larger sample size.

Microenvironment Activatable Nanoprodrug Based on Gripper-like Cyclic Phenylboronic Acid to Precisely and Effectively Alleviate Drug-induced Hepatitis.

Drug-induced hepatitis (DIH), which seriously interferes with disease treatment, is one of the most common reasons for termination of new drugs during preclinical studies or post-marketing surveillance. Although antioxidants and anti-inflammatory agents are promising, their nonspecific distribution and insolubility limit their application. Therefore, precise drug release at the disease site is an important way to alleviate DIH and avoid side effects. Methods: A gripper-like hydrophilic cyclic phenylboronic acid (cPBA) was synthesized and a nanoprodrug (cPBA-BE) was established by coupling cPBA with hydrophobic baicalein (BE). The stimuli-responsive release properties and therapeutic effect of cPBA-BE on drug-injured hepatocyte were investigated. The biodistribution and therapeutic effect of cPBA-BE both in acetaminophen-induced acute hepatitis model and rifampicin-induced chronic hepatitis model were further evaluated. Results: cPBA-BE conjugate could self-assemble into nanoprodrug with cPBA as the hydrophilic external layer and BE as the hydrophobic core. In HepaRG cells, cPBA-BE showed stronger cellular uptake. Due to the H2O2- and acid-sensitivity, cPBA-BE could achieve adequate BE release, significantly resist the depletion of GSH, mitochondrial dysfunction, downregulation of inflammation and cell apoptosis in the acetaminophen injured HepaRG cells. Biodistribution showed that cPBA-BE specifically increased the concentration of BE in the liver of DIH mice. cPBA-BE could alleviate acetaminophen-induced acute hepatitis or rifampicin-induced chronic hepatitis more effectively through relieving the oxidative stress, inflammation and block the neutrophil infiltration in liver. Conclusions: cPBA is expected to be a good platform for constructing injectable nanoprodrug with both H2O2 and pH-responsive properties by coupling a wide range of drugs containing o-diol. In this study, the nanoprodrug cPBA-BE was determined to be effective for alleviating the DIH.

The association between cytochrome P450 polymorphisms and anti-tuberculosis drug-induced liver injury: a systematic review and meta-analysis.

BACKGROUND: Isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA), and ethambutol (EMB) are the four most common drugs for the first-line treatment of tuberculosis (TB). Although chemotherapy drugs are widely used in the treatment of TB, and achieved good results, but the side effects, especially anti-tuberculosis drug-induced liver injury (ATDILI), cannot be overlooked. Many researchers have made efforts to uncover the association of cytochrome P450 (CYP) enzyme genetic polymorphisms with ATDILI. In this study, we systematically reviewed and meta-analyzed the relationship between CYP polymorphism and susceptibility to ATDILI. METHODS: We carried out literature searches of PubMed, Ovid, the Cochrane Library, Web of Science and Chinese National Knowledge Infrastructure (CNKI). Medical Subject Headings (MeSH) terms including "cytochrome P450 enzyme", "drug-induced liver injury", "polymorphism", "tuberculosis", and "hepatotoxicity" were used as keywords for our searches. RESULTS: The pooled odds ratio (OR) of all studies for CYP2E1 to the risk of ATDILI was 1.18 [95% confidence interval (CI): 0.82-1.71]. The articles in this meta-analysis were observed to be mildly heterogeneous. Further subgroup analysis revealed that the patients who receiving a four-drug protocol (INH + RIF + PZA + EMB) or three-drug protocol (INH + RIF + PZA) regimens showed a higher risk of ATDILI than those who receiving INH alone. However, subgroup analyses according to participants' ethnic origin, study type, and the definition of ATDILI produced no statistically significant results. Associations between other genes in the CYP family and ATDILI were indistinct and equivocal. DISCUSSION: Our meta-analysis has uncovered an association between CYP2E1 RsaI/PstI polymorphisms and ATDILI, especially among patients who receive a four-drug (INH + RIF + PZA + EMB) or three-drug (INH + RIF + PZA) anti-TB treatment regimen.

The relationship between prescription of ultrafiltration and intradialytic hypotension in Chinese hemodialysis patients.

BACKGROUND: Intradialytic hypotension (IDH) remains the most frequent severe side effect of hemodialysis (HD) and increases patient morbidity and mortality. Excessive ultrafiltration (UF) is considered the leading cause of IDH. This study developed a suitable prescription of UF to reduce the incidences of IDH episodes. METHODS: A retrospective study was performed to analyze 33,224 HD/hemodiafiltration (HDF) treatments in 312 patients. The prescription of UF were determined following the International Society of Peritoneal Dialysis (ISPD) guideline. The Pearson's method was used to study the correlation between relative variables. The receiver operating characteristic (ROC) curve was used to predict the value of the UF/weight ratio (UF/Wt) for IDH in all patients to establish a diagnostic cut-off point. Univariate and multivariate logistic regression analyses were applied to study the risk factors of IDH. RESULTS: Twelve thousand five hundred and fifty-eight sessions of IDH (38.7%) were identified, among which 1,224 (3.6%) were recorded with intervention against IDH. Both the systolic blood pressure (SBP) and mean arterial pressure (MAP) of the hemodialytic patients were positively correlated with the UF quantity and the UF/Wt, but negatively correlated with blood flow. The ROC curve showed that UF/Wt =0.04 was the cut-off point for IDH. Age [per 10-year increment, odds ratio (OR) =1.005, 95% confidence interval (CI): 1.004 to 1.007, P=0.000], diabetes mellitus (OR =1.209, 95% CI: 1.122 to 1.303, P=0.000), and UF/Wt >0.04 (OR =1.605, 95% CI: 1.532 to 1.682, P=0.000) were all independently associated with higher incidences of IDH. CONCLUSIONS: IDH commonly occurs during HD in Chinese patients. Unchangeable factors such as diabetes and age, and modifiable factors including UF were associated with IDH. A UF/Wt threshold more than 0.04 may be a potential alert for avoiding IDH, especially in the elderly and diabetic patients.

Novel HER2-Targeting Antibody-Drug Conjugates of Trastuzumab Beyond T-DM1 in Breast Cancer: Trastuzumab Deruxtecan(DS-8201a) and (Vic-)Trastuzumab Duocarmazine (SYD985).

Targeted drug delivery has improved cancer treatment significantly in recent years, although it is difficult to achieve. Different approaches have been developed to apply targeted drug delivery. Among which, antibody-drug conjugate (ADC) provides a potentially ideal solution to such a challenge. ADC is an innovative drug treatment model with three key components: payload, monoclonal antibody, and linker. The monoclonal antibody targets the antigen-expressing tumor cells and internalizes the payload linked by the linker to the target cells to reduce the side effects of the traditional chemotherapy drugs. The off-target effect has an excellent therapeutic prospect. Among them, ado-trastuzumab emtansine (T-DM1) is a successful example of targeting human epidermal growth factor receptor-2 (HER2). Its antibody (trastuzumab) is derived from Herceptin with annual sales of more than $6 billion. It has excellent targeting and specific anti-tumor activity against HER2. Its linker is not cleavable and releases the Lys-linker-payload to kill the cells. The two ADCs described here use the same antibody as T-DM1, but the cleavable linker and the more toxic payload allow them to have the not only targeting of T-DM1, but also the reduce T-DM1 resistance and improve efficacy in heterogeneous tumors. This paper describes the mechanism of action and the biochemical characteristics of different parts and preclinical and clinical progress of trastuzumab deruxtecan(DS-8201a) and (vic-)trastuzumab duocarmazine (SYD985).

Pharmacological properties and derivatives of shikonin-A review in recent years.

Shikonin is the major bioactive component extracted from the roots of Lithospermum erythrorhizon which is also known as "Zicao" in Traditional Chinese Medicine (TCM). Recent studies have shown that shikonin demonstrates various bioactivities related to the treatment of cancer, inflammation, and wound healing. This review aimed to provide an updated summary of recent studies on shikonin. Firstly, many studies have demonstrated that shikonin exerts strong anticancer effects on various types of cancer by inhibiting cell proliferation and migration, inducing apoptosis, autophagy, and necroptosis. Shikonin also triggers Reactive Oxygen Species (ROS) generation, suppressing exosome release, and activate anti-tumor immunity in multiple molecular mechanisms. Examples of these effects include modulating the PI3K/AKT/mTOR and MAPKs signaling; inhibiting the activation of TrxR1, PKM2, RIP1/3, Src, and FAK; and regulating the expression of ERP57, MMPs, ATF2, C-MYC, miR-128, and GRP78 (Bip). Next, the anti-inflammatory and wound-healing properties of shikonin were also reviewed. Furthermore, several studies focusing on shikonin derivatives were reviewed, and these showed that, with modification to the naphthazarin ring or side chain, some shikonin derivatives display stronger anticancer activity and lower toxicity than shikonin itself. Our findings suggest that shikonin and its derivatives could serve as potential novel drug for the treatment of cancer and inflammation.

Autophagosomal YKT6 is required for fusion with lysosomes independently of syntaxin 17.

Macroautophagy is an evolutionarily conserved catabolic mechanism that delivers intracellular constituents to lysosomes using autophagosomes. To achieve degradation, lysosomes must fuse with closed autophagosomes. We previously reported that the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein syntaxin (STX) 17 translocates to autophagosomes to mediate fusion with lysosomes. In this study, we report an additional mechanism. We found that autophagosome-lysosome fusion is retained to some extent even in STX17 knockout (KO) HeLa cells. By screening other human SNAREs, we identified YKT6 as a novel autophagosomal SNARE protein. Depletion of YKT6 inhibited autophagosome-lysosome fusion partially in wild-type and completely in STX17 KO cells, suggesting that YKT6 and STX17 are independently required for fusion. YKT6 formed a SNARE complex with SNAP29 and lysosomal STX7, both of which are required for autophagosomal fusion. Recruitment of YKT6 to autophagosomes depends on its N-terminal longin domain but not on the C-terminal palmitoylation and farnesylation that are essential for its Golgi localization. These findings suggest that two independent SNARE complexes mediate autophagosome-lysosome fusion.

LC3- and p62-based biochemical methods for the analysis of autophagy progression in mammalian cells.

Autophagy is an intracellular degradation system that delivers cytoplasmic materials to the lysosome or vacuole. This system plays a crucial role in various physiological and pathological processes in living organisms ranging from yeast to mammals. Thus, an accurate and reliable measure of autophagic activity is necessary. However, autophagy involves dynamic and complicated processes that make it difficult to analyze. The term "autophagic flux" is used to denote overall autophagic degradation (i.e., delivery of autophagic cargo to the lysosome) rather than autophagosome formation. Immunoblot analysis of LC3 and p62/SQSTM1, among other proteins, has been widely used to monitor autophagic flux. Here, we describe basic protocols to measure the levels of endogenous LC3 and p62 by immunoblotting in cultured mammalian cells.

The HOPS complex mediates autophagosome-lysosome fusion through interaction with syntaxin 17.

Membrane fusion is generally controlled by Rabs, soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), and tethering complexes. Syntaxin 17 (STX17) was recently identified as the autophagosomal SNARE required for autophagosome-lysosome fusion in mammals and Drosophila. In this study, to better understand the mechanism of autophagosome-lysosome fusion, we searched for STX17-interacting proteins. Immunoprecipitation and mass spectrometry analysis identified vacuolar protein sorting 33A (VPS33A) and VPS16, which are components of the homotypic fusion and protein sorting (HOPS)-tethering complex. We further confirmed that all HOPS components were coprecipitated with STX17. Knockdown of VPS33A, VPS16, or VPS39 blocked autophagic flux and caused accumulation of STX17- and microtubule-associated protein light chain (LC3)-positive autophagosomes. The endocytic pathway was also affected by knockdown of VPS33A, as previously reported, but not by knockdown of STX17. By contrast, ultraviolet irradiation resistance-associated gene (UVRAG), a known HOPS-interacting protein, did not interact with the STX17-HOPS complex and may not be directly involved in autophagosome-lysosome fusion. Collectively these results suggest that, in addition to its well-established function in the endocytic pathway, HOPS promotes autophagosome-lysosome fusion through interaction with STX17.

Autophagy and human diseases.

Autophagy is a major intracellular degradative process that delivers cytoplasmic materials to the lysosome for degradation. Since the discovery of autophagy-related (Atg) genes in the 1990s, there has been a proliferation of studies on the physiological and pathological roles of autophagy in a variety of autophagy knockout models. However, direct evidence of the connections between ATG gene dysfunction and human diseases has emerged only recently. There are an increasing number of reports showing that mutations in the ATG genes were identified in various human diseases such as neurodegenerative diseases, infectious diseases, and cancers. Here, we review the major advances in identification of mutations or polymorphisms of the ATG genes in human diseases. Current autophagy-modulating compounds in clinical trials are also summarized.

Antitumor and antimetastatic activities of chloroquine diphosphate in a murine model of breast cancer.

Metastatic breast cancers are hard to treat and almost always fatal. Chloroquine diphosphate, a derivative of quinine, has long been used as a potent and commonly used medicine against different human diseases. We therefore investigated the effects of chloroquine diphosphate on a highly metastatic mouse mammary carcinoma cell line. In vitro treatment of 4T1 mouse breast cancer cells with chloroquine diphosphate resulted in significant inhibition of cellular proliferation and viability, and induction of apoptosis in 4T1 cells in a time- and dose-dependent manner. Further analysis indicated that induction of apoptosis was associated with the loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-9 and caspase-3, and cleavage of poly(ADP-ribose) polymerase. The effect of chloroquine diphosphate was then examined using a mice model in which 4T1 cells were implanted subcutaneously. Chloroquine diphosphate (25mg/kg and 50mg/kg, respectively) significantly inhibited the growth of the implanted 4T1 tumor cells and induced apoptosis in the tumor microenvironment. Moreover, the metastasis of tumor cells to the lungs was inhibited significantly and the survival of the mice enhanced. These data suggested that chloroquine diphosphate might have chemotherapeutic efficacy against breast cancer including inhibition of metastasis.

Barbigerone, a natural isoflavone, induces apoptosis in murine lung-cancer cells via the mitochondrial apoptotic pathway.

Barbigerone is a naturally occurring isoflavone with antioxidant activity. In present study, we investigated the antitumor activity of barbigerone against murine lung cancer cells LL/2 and the possible mechanism in vitro. Our results showed that barbigerone inhibited LL/2 cells proliferation in a concentration- and time-dependent manner and caused apoptotic death of LL/2 cells. Barbigerone-induced apoptosis was characterized by enhanced mitochondrial cytochrome c release, activation of caspase-3,-9, but not caspase-8. Exposure of LL/2 cells to barbigerone resulted in upregulation of Bcl-2-associated protein (Bax) and down-regulation of Bcl-2. In addition, proliferation inhibitory effect of barbigerone was associated with decreased level of phosphorylated p42/44 mitogen-activated protein kinase (p42/44 MAPK) and phosphorylated Akt. Moreover, barbigerone exhibit less toxicity to non-cancer cells than tumor cells. In conclusion, our results indicated that barbigerone can inhibit murine lung cancer cell proliferation by inducing apoptosis via mitochondrial apoptotic pathway and by decreasing phosphorylated p42/44 MAPK and Akt. Its potential to be a candidate of anti-cancer agent is worth being further investigated.

Antitumor and antimetastatic activities of vesicular stomatitis virus matrix protein in a murine model of breast cancer.

Vesicular stomatitis virus (VSV) matrix protein (MP) is capable of inducing in vitro apoptosis of tumor cells in the absence of other viral components. Here, we report the potent antitumor and antimetastatic effects of recombinant plasmid pVAX-MP complexed with cationic liposome (DOTAP:Chol) against highly metastatic 4T1 mammary tumor. Mice with 10-day established 4T1 metastatic carcinomas showed a significant reduction in spontaneous lung metastases as well as an evident inhibition in the growths of primary tumors yet without conspicuous systemic toxic effects following a 35-day course of intravenous therapy with pVAX-MP:liposome complexes once every 5 days; the therapy significantly prolonged the survival of the tumor-bearing mice consequently. The histomorphometric analysis revealed an increased percent apoptosis and decreased expression of MMP-9 in pVAX-MP:liposome complexes group. In summary, these results indicate that pVAX-MP:liposome complexes have the ability to inhibit the growths and metastases of mouse breast cancer and they may be a novel and potentially effective therapy against human advanced breast cancer.

Chloroquine inhibits colon cancer cell growth in vitro and tumor growth in vivo via induction of apoptosis.

The present study was to investigate the anticancer effect of chloroquine on proliferation of mouse colon cancer cell line CT26 in vivo and in vitro and the possible mechanism. We found that chloroquine inhibited CT26 proliferation by concentration- and time-dependent manner. This effect was associated with apoptosis induction and decreased level of phosphorylated p42/44 mitogen-activated protein kinase and phosphorylated Akt. The in vivo study showed chloroquine-reduced tumor volume and prolonged survival time in CT26-bearing mice. These observations indicated chloroquine could inhibit CT26 proliferation by inducing apoptosis both in vitro and in vivo, providing its chemotherapeutic potential of human cancers.

Cell growth inhibition, G2/M cell cycle arrest, and apoptosis induced by chloroquine in human breast cancer cell line Bcap-37.

Chloroquine is an antimalarial drug that has been used in the treatment and prophylaxis of malaria since the 1950s. The present study was undertaken to examine the effects of chloroquine on Bcap-37 human breast cancer cells' growth, cell cycle modulation, apoptosis induction, and associated molecular alterations in vitro. The chloroquine treatment decreased the viability of Bcap-37 cells in a concentration- and time-dependent manner, which correlated with G(2)/M phase cell cycle arrest. The chloroquine-mediated cell cycle arrest was associated with a decrease in protein levels/activity of polo-like kinase 1 (Plk1), phosphorylated cell division cycle 25C (Cdc25C), phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), phosphorylated Akt. The chloroquine-treated Bcap-37 cells exhibited a marked decrease in the level of mitochondrial transmembrane potential (DeltaPsim), which was accompanied by the activation of caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Exposure of Bcap-37 cells to chloroquine also resulted in the induction of spindle abnormalities. In conclusion, the findings in this study suggested that chloroquine might have potential anticancer efficacy, which could be attributed, in part, to its proliferation inhibition and apoptosis induction of cancer cells through modulation of apoptosis and cell cycle-related proteins expressions, down-regulation of mitochondrial transmembrane potential (DeltaPsim), and induction of spindle abnormalities.

Pharmacophore modeling and virtual screening for designing potential PLK1 inhibitors.

Pharmacophore models of Polo-like kinase-1 (PLK1) inhibitors have been established by using the HipHop and HypoGen algorithms implemented in the Catalyst software package. The best quantitative pharmacophore model, Hypo1, which has the highest correlation coefficient (0.9895), consists of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic feature, and one hydrophobic aliphatic feature. Hypo1 was further validated by test set and cross validation method. Then Hypo1 was used as a 3D query to screen several databases including Specs, NCI, Maybridge, and Chinese Nature Product Database (CNPD). The hit compounds were subsequently subjected to filtering by Lipinski's rule of five and docking study to refine the retrieved hits and as a result to reduce the rate of false positive. Finally, a total of 20 compounds were selected and have been shifted to in vitro and in vivo studies. As far as we know, this is the first report on the pharmacophore modeling even the first publicly reported virtual screening study of PLK1 inhibitors.