A network-based trans-omics approach for predicting synergistic drug combinations.

BACKGROUND: Combination therapy can offer greater efficacy on medical treatments. However, the discovery of synergistic drug combinations is challenging. We propose a novel computational method, SyndrumNET, to predict synergistic drug combinations by network propagation with trans-omics analyses. METHODS: The prediction is based on the topological relationship, network-based proximity, and transcriptional correlation between diseases and drugs. SyndrumNET was applied to analyzing six diseases including asthma, diabetes, hypertension, colorectal cancer, acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). RESULTS: Here we show that SyndrumNET outperforms the previous methods in terms of high accuracy. We perform in vitro cell survival assays to validate our prediction for CML. Of the top 17 predicted drug pairs, 14 drug pairs successfully exhibits synergistic anticancer effects. Our mode-of-action analysis also reveals that the drug synergy of the top predicted combination of capsaicin and mitoxantrone is due to the complementary regulation of 12 pathways, including the Rap1 signaling pathway. CONCLUSIONS: The proposed method is expected to be useful for discovering synergistic drug combinations for various complex diseases.

Adding drug treatments together can sometimes produce better results for patients. We introduced a new computer-based method called SyndrumNET, designed to identify effective drug combinations for treating diseases. The method uses data about how diseases and drugs interact at a molecular level to predict which drugs work well together. Tested on six different diseases, such as asthma and different types of cancer, SyndrumNET proved to be more accurate than previous approaches. For example, most of the drug combinations predicted by SyndrumNET to rank highly have shown better combination effects on leukemia cells. This method also helped understand why certain drug combinations work better by analyzing their effects on cellular pathways. The findings suggest that SyndrumNET could be a valuable tool in developing more effective treatment for various complex diseases.

Effect of Lipopolysaccharide on the Duration of Zolpidem-Induced Loss of Righting Reflex in Mice.

Zolpidem, a non-benzodiazepine hypnotic, is primarily used to treat insomnia. In a previous study, pior treatment with non-benzodiazepine receptor agonists was associated with inflammation. The present study aimed to clarify the association between the effects of zolpidem and inflammation in mice treated with lipopolysaccharide (LPS), a known model of inflammation. We assessed the zolpidem-induced loss of righting reflex (LORR) duration 24 h after LPS treatment in mice. Additionally, the expressions of γ-aminobutyric acid (GABA)A receptor subunit and K+-Cl- cotransporter isoform 2 (KCC2) mRNA in the hippocampus and frontal cortex were examined in LPS-treated mice. Pretreatment with LPS was associated with significantly prolonged duration of zolpidem-induced LORR compared to control mice. This effect was significantly attenuated by administering bicuculline, a GABAA receptor antagonist, or flumazenil, a benzodiazepine receptor antagonist, in LPS-treated mice. Compared to controls, LPS-treated mice showed no significant change in the expression of GABAA receptor subunits in the hippocampus or frontal cortex. Bumetanide, an Na+-K+-2Cl- cotransporter isoform 1 blocker, attenuated the extended duration of zolpidem-induced LORR observed in LPS-treated mice. LPS significantly decreased Kcc2 mRNA expression in the hippocampus and the frontal cortex. These findings suggest that inflammation increases zolpidem-induced LORR, possibly through a reduction in KCC2 expression.

The Association between PDE5 Inhibitors and Aneurysm/Arterial Dissection:A Pharmacovigilance Study Using WHO Safety Database.

Aneurysm and arterial dissection have been reported as adverse drug events, associated with angiogenesis inhibitors and fluoroquinolones. Specifically, several cases of severe arterial disease following cGMP-specific phosphodiesterase type 5 (PDE5) inhibitors usage have recently been reported. It is necessary to ascertain the risks of serious adverse events caused by PDE5 inhibitors. We aimed to evaluate the association of aneurysm and artery dissection with PDE5 inhibitors using VigiBase, which is a World Health Organization database of spontaneously reported adverse events, for explorative hypothesis-generating analysis. We performed disproportionality analysis using a dataset from inception in 1967 to December 2022 and calculated reporting odds ratios (ROR) between PDE5 inhibitors and arterial diseases. We extracted 195,839 reports on PDE5 inhibitors with 254 reports of arterial disease as adverse events from VigiBase. Disproportionality analysis showed disproportional signals for PDE5 inhibitors (ROR, 2.30;95% confidence intervals, 2.04-2.61);disproportional signals were detected in analyses restricting the lesion site to the aorta or cerebral arteries. From stratified analysis, disproportional signals were noted in females, as well as males, generally recognized as a risk factor for artery diseases. This real-world data analysis suggests that PDE5 inhibitors may play a role in the development of lethal arterial disease. J. Med. Invest. 71 : 134-140, February, 2024.

Adverse events of nivolumab plus ipilimumab versus nivolumab plus cabozantinib: a real-world pharmacovigilance study.

BACKGROUND: No head-to-head clinical trials have compared the differences in adverse events (AEs) between nivolumab plus ipilimumab (NIVO-IPI) and nivolumab plus cabozantinib (NIVO-CABO) in the treatment of metastatic renal cell carcinoma (mRCC). AIM: We analysed the two largest real-world databases, the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) and the World Health Organization's VigiBase, to elucidate the differences in AEs between NIVO-IPI and NIVO-CABO. METHOD: In total, 40,376 and 38,022 records were extracted from FAERS and VigiBase, and 193 AEs were analysed. The reporting odds ratios (ROR) with 95% confidence interval were calculated using a disproportionality analysis (NIVO-CABO/NIVO-IPI). RESULTS: The reported numbers of immune-related AEs, including myocarditis, colitis, and hepatitis, were significantly higher with NIVO-IPI (ROR = 0.18 for FAERS and 0.13 for VigiBase). Contrarily, the reported numbers of other AEs, including gastrointestinal disorders (ROR = 2.68 and 2.92) and skin and subcutaneous tissue disorders (ROR = 2.94 and 3.55), considered to be potentiated by the combination of NIVO and CABO, were higher with NIVO-CABO. CONCLUSION: Our findings contribute to the selection and clinical management of NIVO-IPI and NIVO-CABO, which minimizes the risk of AEs for individual patients with mRCC by considering distinctive differences in the AE profiles.

Lysyl oxidase-like 4 promotes the invasiveness of triple-negative breast cancer cells by orchestrating the invasive machinery formed by annexin A2 and S100A11 on the cell surface.

Background: Our earlier research revealed that the secreted lysyl oxidase-like 4 (LOXL4) that is highly elevated in triple-negative breast cancer (TNBC) acts as a catalyst to lock annexin A2 on the cell membrane surface, which accelerates invasive outgrowth of the cancer through the binding of integrin-ß1 on the cell surface. However, whether this machinery is subject to the LOXL4-mediated intrusive regulation remains uncertain. Methods: Cell invasion was assessed using a transwell-based assay, protein-protein interactions by an immunoprecipitation-Western blotting technique and immunocytochemistry, and plasmin activity in the cell membrane by gelatin zymography. Results: We revealed that cell surface annexin A2 acts as a receptor of plasminogen via interaction with S100A10, a key cell surface annexin A2-binding factor, and S100A11. We found that the cell surface annexin A2/S100A11 complex leads to mature active plasmin from bound plasminogen, which actively stimulates gelatin digestion, followed by increased invasion. Conclusion: We have refined our understanding of the role of LOXL4 in TNBC cell invasion: namely, LOXL4 mediates the upregulation of annexin A2 at the cell surface, the upregulated annexin 2 binds S100A11 and S100A10, and the resulting annexin A2/S100A11 complex acts as a receptor of plasminogen, readily converting it into active-form plasmin and thereby enhancing invasion.

[Development of Preventive Methods for Drug-induced Cardiotoxicity Using a Large-scale Medical Information Database].

Cancer therapies have evolved considerably thereby substantially improving the survival of patients with cancer. However, cardiotoxicity, such as myocarditis and heart failure, induced by anticancer drugs, including immune checkpoint inhibitor(ICI)s and doxorubicin, present serious challenges. Numerous observations have indicated increased risks of cardiotoxicity- and cancer-related mortality in patients with drug-induced cardiotoxicity. Therefore, the prevention and management of drug-induced cardiotoxicity should be prioritized to enable sustainable long-term treatment while preserving patients' quality of life. Recently, medical research has been primarily focused on elucidation of therapeutic benefits and adverse events using medical big data, including worldwide databases of adverse events. The aim of the present study was to establish prevention strategies for drug-induced cardiotoxicity and advance data analytics. A data-driven approach was adopted to comprehensively analyze patient data and drug-induced cardiotoxicity. These data analytics revealed numerous risk factors, leading to the development of drugs that mitigate these factors. Furthermore, many unknown adverse events with molecularly targeted drugs were brought to light. Consequently, the importance of managing adverse events, guided by insights from data science, is predicted to increase. In this symposium review, we introduce our research exemplifying pharmaceutical studies utilizing medical big data. In particular, we discuss in detail the risk factors associated with myocarditis induced by immune checkpoint inhibitors along with prophylactic agents to mitigate doxorubicin-induced cardiotoxicity.

Burden of depressive disorders in Vietnam from 1990 to 2019: A secondary analysis of the Global Burden of Disease Study 2019.

Depressive disorders are among the leading causes of disability globally. However, information on the burden of depressive disorders in Vietnam is limited. We aimed to analyse the burden of depressive disorders in Vietnam from 1990 to 2019. Using data from the Global Burden of Disease Study 2019, prevalence and disability-adjusted life-years (DALYs) were used as indicators to analyse the burden of depressive disorders by age and sex. In 2019 in Vietnam, depressive disorders comprised 2629.1 thousand (95% uncertainty interval (UI): 2233.3-3155.9) estimated cases and 380.6 thousand (95% UI: 258.9-533.8) estimated DALYs. The crude prevalence rate of depressive disorders was higher among females than among males. The DALYs of depressive disorder accounted for a higher percentage of the total all-cause DALYs in the 10-64-year age group than in other age groups. Major depressive disorder was the largest contributor to the burden of depressive disorders. From 1990 to 2019, the crude prevalence and DALY rates per 100 000 population due to depressive disorders increased significantly, whereas age-standardised rates of prevalence and DALYs decreased significantly; the respective average annual percent changes were 0.88% (95% confidence interval: 0.87 to 0.89), 0.68% (0.66 to 0.70), -0.20% (-0.21 to -0.19), and -0.27% (-0.28 to -0.25). Although the age-standardised prevalence rate was lower than that seen globally, depressive disorders were considerable mental health issues in Vietnam. This study will help governments and policymakers to establish appropriate strategies to reduce the burden of these disorders by identifying the priority areas and individuals.

A comparison between the adverse event profiles of patients receiving palbociclib and abemaciclib: analysis of two real-world databases.

BACKGROUND: Palbociclib and abemaciclib are cyclin-dependent kinase (CDK) 4/6 inhibitors currently used to treat breast cancer. Although their therapeutic efficacies are considered comparable, differences in adverse event (AE) profiles of the two drugs remain unclear. AIM: We analysed two real-world databases, the World Health Organization's VigiBase and the Food and Drug Administration Adverse Event Reporting System (FAERS), to identify differences in AE profiles of palbociclib and abemaciclib. METHOD: Data of patients with breast cancer receiving palbociclib or abemaciclib recorded until December 2022 were extracted from the VigiBase and FAERS databases. In total, 200 types of AEs were analysed. The reporting odds ratios were calculated using a disproportionality analysis. RESULTS: Cytopenia was frequently reported in patients receiving palbociclib, whereas interstitial lung disease and diarrhoea were frequently reported in those receiving abemaciclib. Moreover, psychiatric and nervous system disorders were more common in the palbociclib group, whereas renal and urinary disorders were more common in the abemaciclib group. CONCLUSION: This study is the first to show comprehensively the disparities in the AE profiles of palbociclib and abemaciclib. The findings highlight the importance of considering these differences when selecting a suitable CDK4/6 inhibitor to ensure safe and favourable outcomes for patients with breast cancer.

Influence of vasopressin receptor antagonists on triple-whammy acute kidney injury: A VigiBase analysis.

Although diuretics play an important role in triple-whammy acute kidney injury (AKI), it is unclear whether the type of diuretic influences the risk of triple-whammy AKI. The aim of this study was to evaluate whether vasopressin receptor antagonists affect triple-whammy AKI. This cross-sectional study used disproportionality analysis of VigiBase data to assess the risk of AKI with various diuretics. Although multiple logistic regression analysis showed that aldosterone antagonists (odds ratio [OR] 2.19, 95% CI 2.01-2.37), loop diuretics (OR 4.40, 95% CI 4.07-4.76) and thiazide diuretics (OR 1.98, 95% CI 1.83-2.15) increased the risk of AKI in patients who received non-steroidal anti-inflammatory drugs (NSAIDs) and renin-angiotensin system inhibitors (RASi), vasopressin receptor antagonists did not increase the risk of AKI in those patients. Vasopressin receptor antagonists might not influence the development of triple-whammy AKI.

Effect of pre-treatment with EGFR-TKIs on immune checkpoint inhibitor-associated interstitial lung disease in lung cancer patients: Analysis using a Japanese claims database.

BACKGROUND: Immune checkpoint inhibitors (ICI) and epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are key drugs for the treatment of EGFR mutation-positive lung cancer. While previous studies reported that the concomitant use of these drugs increases the risk of interstitial lung disease (ILD), the impact of sequential treatment on ILD risk is unknown. This study aimed to analyze the impact of EGFR-TKI pre-treatment on the risk of developing ILD after subsequent ICI administration. MATERIALS AND METHODS: We conducted a retrospective study using a Japanese health insurance claims database. ILD-naive lung cancer patients who had first ICI administration during the screening period from July 2014 to February 2019 were selected. Patients who had ILD within 1 year of receiving the first ICI dose were included in the ILD group. Multivariate logistic regression analysis was conducted to evaluate the effect of pre-treatment with EGFR-TKI on the development of ICI-associated ILD. RESULTS: A total of 353 patients were included, of which 61 were included in the ILD group. The median time to onset of ILD after ICI administration was 3 months. Multivariate logistic regression analysis revealed that pre-treatment with EGFR-TKI was not associated with ICI-associated ILD (odds ratio: 0.26, 95% confidence interval: 0.033 - 2.01). CONCLUSION: Although further analyses are required to confirm our findings, this study indicated that pre-treatment with EGFR-TKI might not increase the ILD risk after ICI treatment.

International Trends in Adverse Drug Event-Related Mortality from 2001 to 2019: An Analysis of the World Health Organization Mortality Database from 54 Countries.

BACKGROUND AND OBJECTIVE: Adverse drug events (ADEs) are becoming a significant public health issue. However, reports on ADE-related mortality are limited to national-level evaluations. Therefore, we aimed to reveal overall trends in ADE-related mortality across the 21st century on an international level. METHODS: This observational study analysed long-term trends in ADE-related mortality rates from 2001 to 2019 using the World Health Organization Mortality Database. The rates were analysed according to sex, age and region. North America, Latin America and the Caribbean, Western Europe, Eastern Europe and Western Pacific regions were assessed. Fifty-four countries were included with four-character International Statistical Classification of Disease and Related Health Problems, Tenth Revision codes in the database, population data in the World Population Prospects 2019 report, mortality data in more than half of the study period, and high-quality or medium-quality death registration data. A locally weighted regression curve was used to show international trends in age-standardised rates. RESULTS: The global ADE-related mortality rate per 100,000 population increased from 2.05 (95% confidence interval 0.92-3.18) in 2001 to 6.86 (95% confidence interval 5.76-7.95) in 2019. Mortality rates were higher among men than among women, especially in those aged 20-50 years. The population aged ≥ 75 years had higher ADE-related mortality rates than the younger population. North America had the highest mortality rate among the five regions. The global ADE-related mortality rate increased by approximately 3.3-fold from 2001 to 2019. CONCLUSIONS: The burden of ADEs has increased internationally with rising mortality rates. Establishing pharmacovigilance systems can facilitate efforts to reduce ADE-related mortality rates globally.

Concomitant Use of Multiple Nephrotoxins including Renal Hypoperfusion Medications Causes Vancomycin-Associated Nephrotoxicity: Combined Retrospective Analyses of Two Real-World Databases.

There is a growing concern about the relationship between vancomycin-associated nephrotoxicity (VAN) and concomitant use of nephrotoxins. We examined this relationship by combined retrospective analyses of two real-world databases. Initially, the FDA Adverse Event Reporting System (FAERS) was analyzed for the effects of concomitant use of one or more nephrotoxins on VAN and the types of combinations of nephrotoxins that exacerbate VAN. Next, electronic medical records (EMRs) of patients who received vancomycin (VCM) at Tokushima University Hospital between January 2006 and March 2019 were examined to confirm the FAERS analysis. An elevated reporting odds ratio (ROR) was observed with increases in the number of nephrotoxins administered (VCM + one nephrotoxin, adjusted ROR (95% confidence interval [CI]) 1.67 [1.51-1.85]; VCM + ≥2 nephrotoxins, adjusted ROR [95% CI] 1.54 [1.37-1.73]) in FAERS. EMRs analysis showed that the number of nephrotoxins was associated with higher incidences of VAN [odds ratio: 1.99; 95% CI: 1.42-2.78]. Overall, concomitant use of nephrotoxins was associated with an increased incidence of VAN, especially when at least one of those nephrotoxins was a renal hypoperfusion medication (furosemide, non-steroidal anti-inflammatory drugs, and vasopressors). The concomitant use of multiple nephrotoxins, especially including renal hypoperfusion medication, should be avoided to prevent VAN.

Valproic acid treatment attenuates cisplatin-induced kidney injury by suppressing proximal tubular cell damage.

Cisplatin treatment is effective against several types of carcinomas. However, it frequently leads to kidney injury, which warrants effective prevention methods. Sodium valproic acid is a prophylactic drug candidate with a high potential for clinical application against cisplatin-induced kidney injury. Therefore, in this study, we aimed to elucidate the mechanism underlying the prophylactic effect of valproic acid on cisplatin-induced kidney injury in a mouse model and HK2 and PODO cells with cisplatin-induced toxicity. In the mouse model of cisplatin-induced kidney injury, various renal function parameters and tubular damage scores were worsened by cisplatin, but they were significantly improved upon combination with valproic acid. No difference was observed in cisplatin accumulation between the cisplatin-treated and valproic acid-treated groups in whole blood and the kidneys. The mRNA expression levels of proximal tubular damage markers, apoptosis markers, and inflammatory cytokines significantly increased in the cisplatin group 72 h after cisplatin administration but significantly decreased upon combination with valproic acid. In HK2 cells, a human proximal tubular cell line, the cisplatin-induced decrease in cell viability was significantly suppressed by co-treatment with valproic acid. Valproic acid may inhibit cisplatin-induced kidney injury by suppressing apoptosis, inflammatory responses, and glomerular damage throughout the kidneys by suppressing proximal tubular cell damage. However, prospective controlled trials need to evaluate these findings before their practical application.

Angiogenesis inhibitor-specific hypertension increases the risk of developing aortic dissection.

Aortic dissection is an adverse event of angiogenesis inhibitors; however, the association between the drugs and aortic dissection is unclear. Therefore, we investigated if and how angiogenesis inhibitors increase the onset of aortic dissection using pharmacologically-induced aortic dissection-prone model (LAB) mice, cultured endothelial cells, and real-world databases, which is a novel integrated research approach. Disproportionality analysis was performed and calculated using the reporting odds ratio as a risk signal using a worldwide database of spontaneous adverse events to estimate the risk of adverse events. Angiogenesis inhibitors, but not other hypertension-inducing drugs, showed significant risk signals for aortic aneurysms and dissection. A retrospective cohort analysis using JMDC, a medical receipt database in Japan, showed that the history of atherosclerosis and dyslipidemia, but not hypertension, were significantly associated with the onset of aortic dissection during angiogenesis inhibitor medication administration. For in vivo studies, sunitinib (100 mg/kg/day) was administered to LAB mice. Sunitinib increased systolic blood pressure (182 mmHg vs. 288 mmHg with sunitinib; p＜0.01) and the incidence of aortic dissection (40% vs. 59% with sunitinib; p = 0.34) in mice. In vivo and in vitro studies revealed that sunitinib increased endothelin-1 expression and induced endothelial cell damage evaluated by intracellular- and vascular cell adhesion molecule-1 expressions. The increased risk of developing aortic dissection with angiogenesis inhibitors is associated with the development of drug-specific hypertension via endothelial cell damage and endothelin-1 expression. Our findings are invaluable in establishing safer anticancer therapies and strategies to prevent the development of vascular toxicity in high-risk patients.

Trends in Head and Neck Cancer Mortality from 1999 to 2019 in Japan: An Observational Analysis.

Globally, the numbers of head and neck cancer (HNC) cases and related deaths have recently increased. In Japan, few studies have examined crude or age-adjusted HNC mortality rates. Therefore, this study aimed to determine the trends in crude and age-adjusted mortality rates for HNC per million individuals in Japan from 1999 to 2019. Data on HNC-associated deaths were extracted from the national death certificate database using the International Classification of Diseases, Tenth Revision (n = 156,742). HNC mortality trends were analysed using joinpoint regression models to estimate annual percentage change (APC) and average APC (AAPC). Among men, no significant change was observed in the age-adjusted death rate trend from 1999 to 2014; however, a marked decrease was observed from 2014 to 2019. No changing point was observed in women. Age-adjusted mortality rates continuously decreased over the 21-year period, with an AAPC of -0.7% in men and -0.6% in women. In conclusion, the overall trend in age-adjusted rates of HNC-associated deaths decreased, particularly among men, in the past 5 years. These results will contribute to the formulation of medical policies to develop targeted screening and prevention programmes for HNC in Japan and determine the direction of treatment strategies.

Structural characterization of the optical isomers esomeprazole and omeprazole using the JADER and FAERS databases.

BACKGROUND: It is unclear whether the s (-) form of esomeprazole (EPZ) has an improved safety profile when compared with its racemic form omeprazole (OPZ). We assessed the potential complications of these optical isomers when combined with cilostazol, clopidogrel, and prasugrel, which are frequently used concomitant medications. METHODS: Using two adverse event spontaneous reporting databases, Japanese Adverse Drug Event Report (JADER) and FDA Adverse Event Reporting System (FAERS), adverse event names for hemorrhage, venous/arterial embolization, and thrombus were obtained from the Medical Dictionary for Regulatory Activities. Reported odds ratios were calculated using a 2 × 2 contingency table, and a signal was considered present if the lower limit of the 95% confidence interval was >1. RESULTS: In combination with cilostazol, a hemorrhagic signal for OPZ in JADER and arterial emboli and thrombus signals for EPZ were detected in both databases. In combination with clopidogrel, OPZ showed arterial emboli and thrombus signals in JADER and venous/arterial emboli and thrombus signals in FAERS, while EPZ displayed arterial emboli and thrombus signals in FAERS. In contrast, when in combination with prasugrel, there were no adverse event signals in either database. CONCLUSION: This study has confirmed using big data, that EPZ, the optical isomer and racemic form of omeprazole, has the beneficial characteristics of being less sensitive to CYP, as was intended by its design.

Association between immune checkpoint inhibitor-induced myocarditis and concomitant use of thiazide diuretics.

Although an association has been reported between diuretics and myocarditis, it is unclear whether the risk of immune checkpoint inhibitor (ICI)-induced myocarditis is affected by concomitant diuretics. Thus, the aim of this work was to evaluate the impact of concomitant diuretics on ICI-induced myocarditis. This cross-sectional study used disproportionality analysis and a pharmacovigilance database to assess the risk of myocarditis with various diuretics in patients receiving ICIs via the analysis of data entered into the VigiBase database through December 2022. Multiple logistic regression analysis was performed to identify risk factors for myocarditis in patients who received ICIs. A total of 90 611 patients who received ICIs, including 975 cases of myocarditis, were included as the eligible dataset. A disproportionality in myocarditis was observed for loop diuretic use (reporting odds ratio 1.47, 95% confidence interval [CI] 1.02-2.04, P = .03) and thiazide use (reporting odds ratio 1.76, 95% CI 1.20-2.50, P < .01) in patients who received ICIs. The results of the multiple logistic regression analysis showed that the use of thiazides (odds ratio 1.67, 95% CI 1.15-2.34, P < .01) was associated with an increased risk of myocarditis in patients who received ICIs. Our findings may help to predict the risk of myocarditis in patients receiving ICIs.

A polo-like kinase inhibitor identified by computational repositioning attenuates pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease with few effective therapeutic options. Recently, drug repositioning, which involves identifying novel therapeutic potentials for existing drugs, has been popularized as a new approach for the development of novel therapeutic reagents. However, this approach has not yet been fully utilized in the field of pulmonary fibrosis. METHODS: The present study identified novel therapeutic options for pulmonary fibrosis using a systematic computational approach for drug repositioning based on integration of public gene expression signatures of drug and diseases (in silico screening approach). RESULTS: Among the top compounds predicted to be therapeutic for IPF by the in silico approach, we selected BI2536, a polo-like kinase (PLK) 1/2 inhibitor, as a candidate for treating pulmonary fibrosis using an in silico analysis. However, BI2536 accelerated mortality and weight loss rate in an experimental mouse model of pulmonary fibrosis. Because immunofluorescence staining revealed that PLK1 expression was dominant in myofibroblasts while PLK2 expression was dominant in lung epithelial cells, we next focused on the anti-fibrotic effect of the selective PLK1 inhibitor GSK461364. Consequently, GSK461364 attenuated pulmonary fibrosis with acceptable mortality and weight loss in mice. CONCLUSIONS: These findings suggest that targeting PLK1 may be a novel therapeutic approach for pulmonary fibrosis by inhibiting lung fibroblast proliferation without affecting lung epithelial cells. In addition, while in silico screening is useful, it is essential to fully determine the biological activities of candidates by wet-lab validation studies.