Serratiomycins D1-D3, Antibacterial Cyclic Peptides from a Serratia sp. and Structure Revision of Serratiomycin.

Serratiomycin (1) is an antibacterial cyclic depsipeptide, first discovered from a Eubacterium culture in 1998. This compound was initially reported to contain l-Leu, l-Ser, l-allo-Thr, d-Phe, d-Ile, and hydroxydecanoic acid. In the present study, 1 and three new derivatives, serratiomycin D1-D3 (2-4), were isolated from a Serratia sp. strain isolated from the exoskeleton of a long-horned beetle. The planar structures of 1-4 were elucidated by using mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Comparison of the NMR chemical shifts and the physicochemical data of 1 to those of previously reported serratiomycin indeed identified 1 as serratiomycin. The absolute configurations of the amino units in compounds 1-4 were determined by the advanced Marfey's method, 2,3,4,6-tetra-O-acetyl-ß-d-glucopyranosyl isothiocyanate derivatization, and liquid chromatography-mass spectrometric (LC-MS) analysis. Additionally, methanolysis and the modified Mosher's method were used to determine the absolute configuration of (3R)-hydroxydecanoic acid in 1. Consequently, the revised structure of 1 was found to possess d-Leu, l-Ser, l-Thr, d-Phe, l-allo-Ile, and d-hydroxydecanoic acid. In comparison with the previously published structure of serratiomycin, l-Leu, l-allo-Thr, and d-Ile in serratiomycin were revised to d-Leu, l-Thr, and l-allo-Ile. The new members of the serratiomycin family, compounds 2 and 3, showed considerably higher antibacterial activities against Staphylococcus aureus and Salmonella enterica than compound 1.

Soluble ANPEP Released From Human Astrocytes as a Positive Regulator of Microglial Activation and Neuroinflammation: Brain Renin-Angiotensin System in Astrocyte-Microglia Crosstalk.

Astrocytes are major supportive glia and immune modulators in the brain; they are highly secretory in nature and interact with other cell types via their secreted proteomes. To understand how astrocytes communicate during neuroinflammation, we profiled the secretome of human astrocytes following stimulation with proinflammatory factors. A total of 149 proteins were significantly upregulated in stimulated astrocytes, and a bioinformatics analysis of the astrocyte secretome revealed that the brain renin-angiotensin system (RAS) is an important mechanism of astrocyte communication. We observed that the levels of soluble form of aminopeptidase N (sANPEP), an RAS component that converts angiotensin (Ang) III to Ang IV in a neuroinflammatory milieu, significantly increased in the astrocyte secretome. To elucidate the role of sANPEP and Ang IV in neuroinflammation, we first evaluated the expression of Ang IV receptors in human glial cells because Ang IV mediates biological effects through its receptors. The expression of angiotensin type 1 receptor was considerably upregulated in activated human microglial cells but not in human astrocytes. Moreover, interleukin-1ß release from human microglial cells was synergistically increased by cotreatment with sANPEP and its substrate, Ang III, suggesting the proinflammatory action of Ang IV generated by sANPEP. In a mouse neuroinflammation model, brain microglial activation and proinflammatory cytokine expression levels were increased by intracerebroventricular injection of sANPEP and attenuated by an enzymatic inhibitor and neutralizing antibody against sANPEP. Collectively, our results indicate that astrocytic sANPEP-induced increase in Ang IV exacerbates neuroinflammation by interacting with microglial proinflammatory receptor angiotensin type 1 receptor, highlighting an important role of indirect crosstalk between astrocytes and microglia through the brain RAS in neuroinflammation.

Halenaquinol Blocks Staphylococcal Protein A Anchoring on Cell Wall Surface by Inhibiting Sortase A in Staphylococcus aureus.

Sortase A (SrtA) is a cysteine transpeptidase that binds to the periplasmic membrane and plays a crucial role in attaching surface proteins, including staphylococcal protein A (SpA), to the peptidoglycan cell wall. Six pentacyclic polyketides (1-6) were isolated from the marine sponge Xestospongia sp., and their structures were elucidated using spectroscopic techniques and by comparing them to previously reported data. Among them, halenaquinol (2) was found to be the most potent SrtA inhibitor, with an IC50 of 13.94 µM (4.66 µg/mL). Semi-quantitative reverse transcription PCR data suggest that halenaquinol does not inhibit the transcription of srtA and spA, while Western blot analysis and immunofluorescence microscopy images suggest that it blocks the cell wall surface anchoring of SpA by inhibiting the activity of SrtA. The onset and magnitude of the inhibition of SpA anchoring on the cell wall surface in S. aureus that has been treated with halenaquinol at a value 8× that of the IC50 of SrtA are comparable to those for an srtA-deletion mutant. These findings contribute to the understanding of the mechanism by which marine-derived pentacyclic polyketides inhibit SrtA, highlighting their potential as anti-infective agents targeting S. aureus virulence.

Genomic and Spectroscopic Signature-Based Discovery of Natural Macrolactams.

The logical and effective discovery of macrolactams, structurally unique natural molecules with diverse biological activities, has been limited by a lack of targeted search methods. Herein, a targeted discovery method for natural macrolactams was devised by coupling genomic signature-based PCR screening of a bacterial DNA library with spectroscopic signature-based early identification of macrolactams. DNA library screening facilitated the efficient selection of 43 potential macrolactam-producing strains (3.6% of 1,188 strains screened). The PCR amplicons of the amine-deprotecting enzyme-coding genes were analyzed to predict the macrolactam type (α-methyl, α-alkyl, or ß-methyl) produced by the hit strains. 1H-15N HSQC-TOCSY NMR analysis of 15N-labeled culture extracts enabled macrolactam detection and structural type assignment without any purification steps. This method identified a high-titer Micromonospora strain producing salinilactam (1), a previously reported α-methyl macrolactam, and two Streptomyces strains producing new α-alkyl and ß-methyl macrolactams. Subsequent purification and spectroscopic analysis led to the structural revision of 1 and the discovery of muanlactam (2), an α-alkyl macrolactam with diene amide and tetraene chromophores, and concolactam (3), a ß-methyl macrolactam with a [16,6,6]-tricyclic skeleton. Detailed genomic analysis of the strains producing 1-3 identified putative biosynthetic gene clusters and pathways. Compound 2 displayed significant cytotoxicity against various cancer cell lines (IC50 = 1.58 µM against HCT116), whereas 3 showed inhibitory activity against Staphylococcus aureus sortase A. This genomic and spectroscopic signature-based method provides an efficient search strategy for new natural macrolactams and will be generally applicable for the discovery of nitrogen-bearing natural products.

Evaluation of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the discrimination of Lacticaseibacillus species.

The closely related species, Lacticaseibacillus casei, L. paracasei, L. rhamnosus, L. chiayiensis, and L. zeae, are difficult to accurately discriminate by conventional identification methods. In this study, the bioTyper and in-house database of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was evaluated to discriminate five Lacticaseibacillus species. From the mass spectra of 130 isolates aligned with databases, 118 strains were correctly identified. On the other hand, databases could not accurately differentiate 12 isolates such as L. casei, L. rhamnosus and L. chiayiensis because the same colony was identified as two species with similar score. To overcome the database's limitations, the mass spectra were analyzed to discover species-specific protein peaks. The peaks at 6731 ± 1, 6849 ± 1, 7008 ± 1, 7376 ± 1, and 2593 ± 1 m/z were specifically found in the reference strains of L. casei, L. paracasei, L. rhamnosus, L. chiayiensis, and L. zeae, respectively. These peaks confirmed that the five peaks were consistently present in each species using 130 strains isolated from food samples. Our results demonstrate the high-resolution of MALDI-TOF MS technique for rapid and accurate classification of five species when used with databases coupled to specific peaks.

Ligiamycins A and B, Decalin-Amino-Maleimides from the Co-Culture of Streptomyces sp. and Achromobacter sp. Isolated from the Marine Wharf Roach, Ligia exotica.

Streptomyces sp. GET02.ST and Achromobacter sp. GET02.AC were isolated together from the gut of the wharf roach, Ligia exotica, inhabiting the intertidal zone of the west coast of Korea. The co-cultivation of these two strains significantly induced the production of two new metabolites, ligiamycins A (1) and B (2), which were barely detected in the single culture of Streptomyces sp. GET02.ST. The planar structures of ligiamycins A (1) and B (2) were elucidated as new decalins coupled with amino-maleimides by the analysis of various spectroscopic data, including nuclear magnetic resonance (NMR), ultraviolet (UV), and mass (MS) data. The assignment of two nitrogen atoms in amino-maleimide in 1 was accomplished based on 1H-15N heteroatom single quantum coherence spectroscopy (HSQC) NMR experiments. The relative configurations of the ligiamycins were determined using rotating frame Overhauser effect spectroscopy (ROESY) NMR data, and their absolute configurations were deduced by comparing their experimental and calculated optical rotations. Ligiamycin A (1) displayed antibacterial effects against Staphylococcus aureus and Salmonella enterica, while ligiamycin B (2) exhibited mild cell cytotoxicity against human colorectal cancer cells.

Inhibitory Effects of Nitrogenous Metabolites from a Marine-Derived Streptomyces bacillaris on Isocitrate Lyase of Candida albicans.

Two nitrogenous metabolites, bacillimide (1) and bacillapyrrole (2), were isolated from the culture broth of the marine-derived actinomycete Streptomyces bacillaris. Based on the results of combined spectroscopic and chemical analyses, the structure of bacillimide (1) was determined to be a new cyclopenta[c]pyrrole-1,3-dione bearing a methylsulfide group, while the previously reported bacillapyrrole (2) was fully characterized for the first time as a pyrrole-carboxamide bearing an alkyl sulfoxide side chain. Bacillimide (1) and bacillapyrrole (2) exerted moderate (IC50 = 44.24 µM) and weak (IC50 = 190.45 µM) inhibitory effects on Candida albicans isocitrate lyase, respectively. Based on the growth phenotype using icl-deletion mutants and icl expression analyses, we determined that bacillimide (1) inhibits the transcriptional level of icl in C. albicans under C2-carbon-utilizing conditions.

Novel approaches for the identification of microbial communities in kimchi: MALDI-TOF MS analysis and high-throughput sequencing.

Complex interactions occur within microbial communities during the fermentation process of kimchi. Identification of these microorganisms provides the essential information required to improve food quality and to understand their role in this process. This was the first study to compare two methods for accuracy in the identification of microbial community changes during the fermentation of kimchi by comparing a culture-dependent (MALDI-TOF MS analysis) and a culture-independent method (high-throughput sequencing) of 16S rRNA gene fragment). Members of the Lactobacillus-related genera, Leuconostoc, and Weissella were identified as the predominant microorganisms by both methods. The culture-independent method was able to additionally identify non-lactic acid bacteria and yeasts, such as Kazachstania in kimchi. However, high-throughput sequencing failed to accurately recognize Latilactobacillus sakei, Latilactobacillus curvatus, Lactiplantibacillus plantarum, and W. cibaria, which played an important role in kimchi fermentation, as this method only allowed for identification at the genus level. Conversely, MALDI-TOF MS analysis could identify the isolates at the species level. Also, culture-dependent method could identify predominant species in viable cell communities. The culture-dependent method and culture-independent method provided complementary information by producing a more comprehensive view of the microbial ecology in fermented kimchi.

Inhibitory Effects of Epipolythiodioxopiperazine Fungal Metabolites on Isocitrate Lyase in the Glyoxylate Cycle of Candida albicans.

Four epipolythiodioxopiperazine fungal metabolites (1-4) isolated from the sponge-derived Aspergillus quadrilineatus FJJ093 were evaluated for their capacity to inhibit isocitrate lyase (ICL) in the glyoxylate cycle of Candida albicans. The structures of these compounds were elucidated using spectroscopic techniques and comparisons with previously reported data. We found secoemestrin C (1) (an epitetrathiodioxopiperazine derivative) to be a potent ICL inhibitor, with an inhibitory concentration of 4.77 ± 0.08 µM. Phenotypic analyses of ICL-deletion mutants via growth assays with acetate as the sole carbon source demonstrated that secoemestrin C (1) inhibited C. albicans ICL. Semi-quantitative reverse-transcription polymerase chain reaction analyses indicated that secoemestrin C (1) inhibits ICL mRNA expression in C. albicans under C2-assimilating conditions.

Human Flourishing in Adolescents with Cancer: Experiences of Pediatric Oncology Health Care Professionals.

PURPOSE: This study explores human flourishing (HF) in adolescents with cancer (AC) as witnessed by their health care providers, and it develops a list of critical attributes associated with HF to describe the positive outcomes witnessed. DESIGN AND METHODS: Our study used a qualitative descriptive design incorporating data from an open-ended electronic survey and semi-structured individual interviews with 17 pediatric oncology health care providers. RESULTS: We found 3 major themes (positive forward motion, connectedness, and self-character) representing 11 critical attributes of human flourishing in AC: (1) initiative and enterprise, (2) positivity and evocativeness, (3) tranquility and maturity, (4) perseverance and tenacity, (5) compassion and empathy, (6) social engagement and connection, (7) wisdom and translation into life, (8) supportive background, (9) self-awareness and self-agency, (10) transcendence and full potential, and (11) meaning-making. CONCLUSIONS: Understanding the concept of HF as it applies to the needs of AC is a step toward establishing it as a comprehensive health care goal and toward developing care provider guidelines for its promotion. PRACTICE IMPLICATIONS: Given the attributes of HF in AC, nurses can consider HF as an ultimate nursing care outcome and should focus on goals of care beyond disease treatment and symptoms mitigation when providing care for this population. Holistic, individualized assessment, timely care during each phase of treatment, and developmentally tailored intervention should be provided.

As(III) adsorption onto Fe-impregnated food waste biochar: experimental investigation, modeling, and optimization using response surface methodology.

Biochar derived from food waste was modified with Fe to enhance its adsorption capacity for As(III), which is the most toxic form of As. The synthesis of Fe-impregnated food waste biochar (Fe-FWB) was optimized using response surface methodology (RSM), and the pyrolysis time (1.0, 2.5, and 4.0 h), temperature (300, 450, and 600 °C), and Fe concentration (0.1, 0.3, and 0.5 M) were set as independent variables. The pyrolysis temperature and Fe concentration significantly influenced the As(III) removal, but the effect of pyrolysis time was insignificant. The optimum conditions for the synthesis of Fe-FWB were 1 h and 300 °C with a 0.42-M Fe concentration. Both physical and chemical properties of the optimized Fe-FWB were studied. They were also used for kinetic, equilibrium, thermodynamic, pH, and competing anion studies. Kinetic adsorption experiments demonstrated that the pseudo-second-order model had a superior fit for As(III) adsorption than the pseudo-first-order model. The maximum adsorption capacity derived from the Langmuir model was 119.5 mg/g, which surpassed that of other adsorbents published in the literature. Maximum As(III) adsorption occurred at an elevated pH in the range from 3 to 11 owing to the presence of As(III) as H2AsO3- above a pH of 9.2. A slight reduction in As(III) adsorption was observed in the existence of bicarbonate, hydrogen phosphate, nitrate, and sulfate even at a high concentration of 10 mM. This study demonstrates that aqueous solutions can be treated using Fe-FWB, which is an affordable and readily available resource for As(III) removal.

A qualitative analysis of nursing students' tweets during the COVID-19 pandemic.

The COVID-19 outbreak has profoundly changed daily life and the ways in which students learn and interact. This study explores the nature and content of tweets posted by students enrolled in nursing programs (hereafter nursing students) in the United Kingdom, the United States, and South Korea during the COVID-19 pandemic between March 4 and April 7, 2020. A total of 8856 tweets from the Twitter accounts of 95 self-identified nursing students were included in our qualitative analysis. The findings revealed five categories of tweet content: (i) reactions to COVID-19; (ii) everyday life; (iii) role as a student; (iv) social connections; and (v) sociopolitical issues. Students shared concerns about the impact of COVID-19 on their education, discussed their experiences as nursing students, tweeted details of their daily lives, and sought social connections for support as well as for information sharing. The findings of this study can inform nurse educators to better understand their students' responses to and sentiments about the COVID-19 pandemic. Nurse educators should incorporate this understanding into curricula for pandemic preparedness and response efforts.

Facebook Recruitment for Children with Advanced Cancer and Their Parents: Lessons from a Web-based Pediatric Palliative Intervention Study.

Participant recruitment for pediatric palliative intervention studies is a chronic challenge for researchers. Digital recruitment strategies, or digital technology-assisted recruitment methods used to remotely reach and enroll research subjects, can help address these recruitment challenges for pediatric palliative care clinical trials. This study (a) describes Facebook recruitment procedures targeting children with cancer and their parents for a pediatric palliative intervention randomized clinical trial, (b) reports recruitment results, and (c) discusses successful strategies to recruit pediatric populations via Facebook advertisements. Researchers used Facebook advertisements to recruit children with advanced cancer (aged 7 to 17 years) for a web-based legacy intervention. Between years 2015 and 2018, our research team enrolled 150 child-parent dyads (N= 300) to participate in the web-based legacy program. Results suggest that Facebook advertisements can be a successful tool to access and recruit pediatric populations with life-threatening conditions. Further research is needed to determine how innovative social-media recruitment strategies could be used in other populations of patients with serious illnesses and their caregivers to further advance the science in palliative care.

Isocadiolides A-H: Polybrominated Aromatics from a Synoicum sp. Ascidian.

Isocadiolides A-H (1-8) and cadiolide N (9), new polybrominated aromatic compounds, were isolated from a Korean Synoicum sp. ascidian. On the basis of the results of extensive spectroscopic analyses, these compounds possessed tris-bromohydroxyphenyl moieties as a common structural motif, while their cores varied [cyclopentenedione (1-5), dihydrofuran (6 and 7), pyranone (8), and furanone (9)], reflecting different extents of rearrangement and oxidation. Several of these compounds exhibited weak antibacterial activities and moderate abilities to inhibit the microbial enzymes sortase A and isocitrate lyase.

Neuroprotective effect of Annona muricata-derived polysaccharides in neuronal HT22 cell damage induced by hydrogen peroxide.

Crude extracts and phytochemical compounds derived from Annona muricata leaves have been demonstrated to exert neuroprotective effects. However, the neuroprotective effects of Annona muricata leaves-derived polysaccharide extracts (ALPs) have not been investigated. ALP treatment was shown to induce concentration-dependent antioxidant activity in HT22 cells, and to increase cell viability in H2O2-treated HT22 cells. These effects were correlated with a decrease in major components of oxidation, including: Ca2+, ROS, and malondialdehyde (MDA). Mediators of the intracellular response to oxidation, including Bax, cytochrome c, and cleaved caspases-3, -8, -9, MAPKs, and NF-κB, were positively influenced by ALP treatment under conditions of H2O2-mediated oxidative stress. In addition, ALP restored the expression of superoxide dismutase (SOD) and associated signaling pathways (PARP, PI3K/AKT and Nrf2-mediated HO-1/NQO-1) following H2O2 treatment. These results provide new pharmacological evidence that ALP facilitates neuroprotection via prevention of neuronal oxidative stress and promotion of cell survival signaling pathways.Abbreviations: ABTS: 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonicacid); AD: Alzheimer's disease; ALP: polysaccharide extracts isolated from Annona muricata leaves; ARE: antioxidant response element; DPPH: 1,1-diphenyl-picrylhydrazyl; DCFH-DA: 2',7'-dichlorofluorescin diacetate; ECL: electrochemiluminescence; ERK: extracellular regulated kinase; FBS: Fetal bovine serum; FITC: fluorescein isothiocyanate; FRAP: ferric reducing antioxidant power; HO-1: Heme oxygenase-1; JNK: c-jun N-terminal kinase; MAPKs: mitogen-activated protein kinases; MDA: malondialdehyde; MMP: mitochondrial membrane potential; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide; NQO1: NAD(P)H:quinine oxidoreductase 1, Nrf2: nuclear factor-E2-related factor 2; PD: parkinson's disease; PI3K: phosphatidylinositol-3kinase; PVDF: polyvinylidene difluoride; ROS: reactive oxygen species; SOD: Superoxidedismutase; TPTZ: tripydyltriazine.

Novel real-time PCR assay for Lactobacillus casei group species using comparative genomics.

The Lactobacillus casei group, which includes the closely related species L. casei, L. paracasei, L. rhamnosus, and L. chiayiensis, has been under debate regarding its taxonomy because of the difficulty in distinguishing the species from each other. In the present study, we developed a novel real-time PCR assay for distinguishing the L. casei group species. The pan-genome, as determined by the genomes of 44 strains, comprised 6789 genes, comparative genomic analysis showed that L. casei group strains were classified by species. Based on these results, species-specific genes were identified, and primers were designed from those genes. Real-time PCR clearly distinguished each species of the L. casei group and specifically amplified only to the target species. The method was applied to 29 probiotic products, and the detected results and label claims were compared. Total 23 products were in accordance with the label claims, and the remaining products contained species different from those stated in the label claims. Our method can rapidly and accurately distinguish the L. casei group species in a single reaction. Hence, our assay can be applied to identify L. casei group species from food or environmental samples and to accurately determine the nomenclature of the species.

Antibacterial Activity of Chromomycins from a Marine-Derived Streptomyces microflavus.

A marine-derived actinomycete (Streptomyces sp. MBTI36) exhibiting antibacterial activities was investigated in the present study. The strain was identified using genetic techniques. The 16S rDNA sequence of the isolate indicated that it was most closely related to Streptomyces microflavus. Furthermore, a new chromomycin A9 (1), along with chromomycin Ap (2), chromomycin A2 (3), and chromomycin A3 (4), were isolated from the ethyl acetate extract. Their structures were determined using extensive spectroscopic methods including 1D and 2D NMR, and HRMS, as well as comparisons with previously reported data. Compounds 1-4 showed potent antibacterial activities against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). During a passage experiment, minimum inhibitory concentration (MIC) values for compounds 1-4 showed no more than a 4-fold increase from the starting MIC value, indicating that no resistance was detected over the 21 passages.

Sortase A-Inhibitory Metabolites from a Marine-Derived Fungus Aspergillus sp.

Seven alkaloidal compounds (2-8) and one polyketide (1) were isolated from a semisolid rice culture of the marine-derived fungus Aspergillus sp. F452. Structures of the isolated compounds were elucidated based on spectroscopic data and comparisons with previously reported data. The alkaloidal compounds (2-8) displayed weak to moderate inhibitory activities against Staphylococcus aureus-derived sortase A (SrtA) without affecting cell viability. Aspermytin A (1) strongly inhibited SrtA activity, with an IC50 value of 146.0 µM, and significantly reduced bacterial adherence to fibronectin-coated surfaces. The present results indicate that the underlying mechanism of action of compound 1 is associated with the inhibition of SrtA-mediated S. aureus adhesion to fibronectin, thus potentially serving as an SrtA inhibitor.

Bioactive Bis(indole) Alkaloids from a Spongosorites sp. Sponge.

Six new bis(indole) alkaloids (1-6) along with eight known ones of the topsentin class were isolated from a Spongosorites sp. sponge of Korea. Based on the results of combined spectroscopic analyses, the structures of spongosoritins A-D (1-4) were determined to possess a 2-methoxy-1-imidazole-5-one core connecting the indole moieties, and these were linked by a linear urea bridge for spongocarbamides A (5) and B (6). The absolute configurations of spongosoritins were assigned by electronic circular dichroism (ECD) computation. The new compounds exhibited moderate inhibition against transpeptidase sortase A and weak inhibition against human pathogenic bacteria and A549 and K562 cancer cell lines.

Activity-Based Protein Profiling Reveals Potential Dasatinib Targets in Gastric Cancer.

Dasatinib is a multi-target kinase inhibitor, whose targets include BCR-ABL, SRC family kinases, and various cancer kinases. The elevated SRC activity in gastric cancer (GC) has prompted the need for the therapeutic application of dasatinib in GC. We observed that the efficacy of dasatinib varied with the GC cell lines. The differential effect of dasatinib was not correlated with the basal SRC activity of each cell line. Moreover, the GC cell lines showing the strong antitumor effects of dasatinib were refractory to other SRC inhibitors, i.e., bosutinib and saracatinib, suggesting that unexpected dasatinib's targets could exist. To profile the targets of dasatinib in GC, we performed activity-based protein profiling (ABPP) via mass spectrometry using a desthiobiotin-ATP probe. We identified 29 and 18 kinases as potential targets in dasatinib-sensitive (SNU-216, MKN-1) and -resistant (SNU-484, SNU-601) cell lines, respectively. The protein-protein interaction mapping of the differential drug targets in dasatinib-sensitive and -resistant GC using the STRING database suggested that dasatinib could target cellular energy homeostasis in the drug-sensitive GC. RNAi screening for identified targets indicated p90RSK could be a novel dasatinib target, which is important for maintaining the viability and motility of GC cells. Further functional validation of dasatinib off-target actions will provide more effective therapeutic options for GC.