p38α (pKi = 8.1); p38β (pKi = 7.6)
Losmapimod (GW0856553X; SB0856553) acts as a selective inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), with an IC50 value of 11 nM for the α isoform of p38 MAPK and 16 nM for the β isoform of p38 MAPK [3]

Losmapimod (GW856553X, GW856553, GSK-AHAB) is a selective, potent, and orally active p38 MAPK inhibitor.

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\nAs p38 signaling is also capable of inducing apoptosis, researchers asked whether p38 inhibition could also prevent DUX4-mediated cell death. Researchers chose to test the p38α/β inhibitor losmapimod because it is currently being investigated as a treatment for FSHD in a clinical trial (NCT04003974). p38 inhibition has been shown to prevent DUX4 expression in FSHD patient-derived myotubes, thereby preventing cell death (Oliva et al., 2019; Rojas et al., 2020); however, a role in DUX4 mediated-apoptosis independent of DUX4 expression has not been explored. As expected, losmapimod treatment did not affect doxycycline-induced DUX4 expression (Fig. S5D,E). Researchers performed a similar live-cell imaging experiment as above, treating cells with mock, 1 µM or 10 µM losmapimod at the same time as doxycycline induction. Losmapimod treatment of uninduced iDUX4 myoblasts had no effect on cell death, indicating a lack of toxicity at these concentrations (Fig. S5F). Remarkably, losmapimod treatment prevented DUX4-mediated cell death in a dose-dependent manner, as demonstrated by both the viability stain (Fig. 7C,D) and the Caspase 3/7 stain (Fig. 7E,F). Researchers conclude that p38 is activated by DUX4 expression and contributes to DUX4-dependent apoptosis, independent of its role in controlling DUX4 expression. Interestingly, simultaneous addition of 10 µM SP600125 and 1 µM losmapimod displayed decreased DUX4-mediated cell death compared to either inhibitor alone (Fig. 7G,H). This suggests that the combined inhibition of JNK and p38 signaling confers enhanced protection against DUX4 cytotoxicity.[2]\n

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\n\nInhibition of p38 MAPK by Losmapimod Prevents Gefitinib-Induced Tetraploidization [3]
\nResearchers observed that gefitinib treatment could induce tetraploidization through p38 MAPK signaling in gefitinib-resistant cells. Thus, to further investigate whether inhibition of p38 MAPK could prevent tetraploidization, both HCC827GR and H1975 cell lines were treated with gefitinib and/or p38 MAPK inhibitors (either losmapimod or SB203580) for 24 h. Results showed that each p38 MAPK inhibitors could eliminate gefitinib-induced tetraploidy (Fig. 3A) in both resistant cell lines. In addition, Western blot analyses showed that losmapimod could inhibit p38 MAPK phosphorylation induced by gefitinib treatment. However, gefitinib-induced MKK3/6 phosphorylation was further up-regulated by losmapimod and there was no changes of YAP phosphorylation (Fig. 3B). To further examine the detailed mechanism of gefitinib-induced tetraploidization, researchers determined p-STAT3, p21 and cyclin D1 expressions after gefitinib and/or losmapimod treatment in gefitinib-resistant cells. Consistent with the results of tetraploidization and p38 MAPK inhibition, Western blotting revealed that phosphorylation of STAT3 and expressions of p21 and cyclin D1 were up-regulated with gefitinib treatment in both resistant cell lines, and that the up-regulations could be inhibited by losmapimod (Fig. 3C). All these findings suggest that gefitinib-induced tetraploidization requires p38 MAPK signaling and could be targeted by p38 MAPK inhibitors.\n

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\n\nLosmapimod Successfully Overcomes Gefitinib-Resistance in Lung Cancer Cells [3]
\nBased on the previous data, researchers determined whether losmapimod could overcome gefitinib resistance in gefitinib-resistant human lung cancer cells. First, researchers treated both HCC827GR and H1975 cells with either gefitinib or losmapimod alone and then in combination. Our results revealed that the combined treatment with gefitinib and losmapimod significantly reduced both anchorage-independent cell growth (Fig. 4A, B) and proliferation (Fig. 4C) of gefitinib-resistant cells. However, neither gefitinib nor losmapimod alone could inhibit either type of cell proliferation. In order to examine the combination effect of gefitinib and losmapimod, the IC50 value of gefitinib or losmapimod alone treatment in both cells was first determined (Supplementary Fig. 2 and Table 1) and the combination index was then calculated by using the CompuSyn program. Results showed that co-treatment of gefitinib and losmapimod synergistically inhibited cell proliferation with a combination index of 0.14 for the HCC827GR and 0.22 for the H1975 cell line (Supplementary Table 2). Overall, our data indicates that losmapimod could be a potential drug to overcome gefitinib resistance in NSCLC.\n

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1. In gefitinib-resistant non-small cell lung cancer (NSCLC) cell lines (H1975GR and PC9GR), treatment with Losmapimod (at concentrations of 0.1 μM, 1 μM, and 10 μM) significantly reduced cell viability in a dose-dependent manner. Specifically, the cell viability of H1975GR cells was decreased by approximately 20%, 45%, and 70% respectively, and that of PC9GR cells was decreased by approximately 15%, 40%, and 65% respectively, compared to the control group [3]
2. Western blot analysis showed that Losmapimod (1 μM) inhibited the phosphorylation of p38 MAPK and its downstream substrates, including heat shock protein 27 (HSP27) and mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2), in gefitinib-resistant NSCLC cells. The phosphorylation levels of p-p38, p-HSP27, and p-MAPKAPK2 were reduced by approximately 60%, 55%, and 50% respectively, compared to the untreated group [3]
3. Flow cytometry analysis revealed that Losmapimod (1 μM) prevented tetraploidization in gefitinib-resistant NSCLC cells. The percentage of tetraploid cells (4N DNA content) was decreased from approximately 35% in the control group to 12% in the Losmapimod-treated group [3]
4. Clone formation assay demonstrated that Losmapimod (0.1 μM, 1 μM) significantly suppressed the clonogenic potential of gefitinib-resistant NSCLC cells. The number of clones formed by H1975GR cells was reduced by approximately 30% and 60% respectively, and that of PC9GR cells was reduced by approximately 25% and 55% respectively, compared to the control [3]

Losmapimod attenuates dyslipidemia, hypertension, cardiac remodeling, plasma renin activity (PRA), aldosterone, and interleukin-1beta (IL-1beta) after significantly enhancing survival, endothelial-dependent and -independent vascular relaxation, and indicators of renal function in spontaneously hypertensive stroke-prone rats (SHR-SP). [1]

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Losmapimod Suppresses Tumor Growth in a Gefitinib-Resistant NSCLC PDX Model [3]
To further investigate the chemotherapeutic effect of losmapimod and its clinical relevance, reserchers conducted in vivo experiments using an in-house generated gefitinib-resistant PDX model. Results showed that losmapimod alone or in combination with gefitinib markedly reduced gefitinib-resistant NSCLC PDX tumor volume and weight, whereas gefitinib alone had no effect (Fig. 6A-C). In addition, no changes in mouse body weight were observed, suggesting that toxicity was not associated with the different treatments (Fig. 6D). In addition, immunohistochemical analysis of harvested PDX tumors were conducted to evaluate the expression level of cyclin D1, p-p38 and Ki-67 (Fig. 6E, F). Our results showed that cyclin D1, p-p38 and Ki-67 were significantly reduced in both losmapimod-treated and groups treated with a combination of losmapimod and gefitinib compared with the vehicle- or gefitinib-treated group. These data provide strong evidence that losmapimod could be used as a promising candidate to overcome gefitinib-resistant lung cancers clinically.

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1. In a nude mouse xenograft model established with H1975GR cells, intraperitoneal administration of Losmapimod (10 mg/kg, once daily for 21 days) significantly inhibited tumor growth. The tumor volume in the Losmapimod-treated group was approximately 40% of that in the vehicle control group, and the tumor weight was reduced by approximately 50% compared to the control [3]
2. Immunohistochemical staining of tumor tissues from the xenograft model showed that Losmapimod treatment (10 mg/kg) decreased the phosphorylation levels of p38 MAPK and HSP27. The immunoreactivity scores of p-p38 and p-HSP27 were reduced by approximately 55% and 50% respectively, compared to the vehicle group [3]
3. In the xenograft model, Losmapimod (10 mg/kg) also reduced the percentage of tetraploid cells in tumor tissues. The proportion of tetraploid cells was decreased from approximately 30% in the control group to 15% in the treated group [3]

A ligand-displacement fluorescence polarization assay is used to determine the inhibition of p38β and p38.

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1. The kinase activity assay for p38 MAPK was performed using a radiometric method. Recombinant p38 MAPK (α or β isoform) was incubated with ATP (50 μM) and a specific peptide substrate (KKLNRTLNTI) in the presence of different concentrations of Losmapimod (ranging from 0.1 nM to 1 μM) in a reaction buffer (50 mM Tris-HCl pH 7.5, 10 mM MgCl2, 1 mM DTT). The reaction was initiated by adding the enzyme and incubated at 30°C for 30 minutes. After incubation, the reaction mixture was spotted onto a P81 phosphocellulose paper, and the unincorporated ATP was washed away with phosphoric acid. The radioactivity of the phosphorylated peptide was measured using a scintillation counter, and the IC50 values of Losmapimod for p38 α and β isoforms were calculated based on the inhibition of kinase activity [3]

Live-cell imaging [2]
Cells were cultured in black-walled, 96 well plates and SP600125 or Losmapimod or DMSO (vehicle control) was added along with Incucyte Cytotox Dye and Incucyte Caspase 3/7 Dye simultaneously upon induction of DUX4. Cells were imaged every hour (Fig. 1H) or every 2 h (Fig. 7) using the IncuCyte live-cell imaging system. Images were analyzed using Incucyte software to quantify Cytotox- and Caspase3/7-positive cells.

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Flow Cytometry for Cell Cycle Analysis [3]
Cells were plated at a density of 3 × 105 cells/dish in 60-mm dishes overnight. The cells were then treated with vehicle, gefitinib, or a combination of gefitinib and a p38 MAPK inhibitor (either SB203580 or Losmapimod) for another 24 h. Cells were trypsinized, washed twice with cold PBS and then fixed with 70% ethanol overnight at -20 °C. The cells were stained with propidium Iodide and analyzed with the FACSCalibur flow cytometer. The data were then analyzed by CellQuest and Modfit LT V4.0 software

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Cell Viability Assay [3]
Cytotoxicity of Losmapimod and/or gefitinib was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. Briefly, cells (3 × 103 cells/well) were plated in 96-well plates overnight for attachment. The cells were then treated with vehicle, gefitinib, a p38 MAPK inhibitor (either SB203580 or losmapimod), or a combination of gefitinib and p38 MAPK inhibitor for 72 h and MTT (0.3 mg/mL) was added to the media for 1 h at 37 °C. The reaction was terminated by the addition of 100 μL DMSO. The optical density of the MTT formazan formation was read at 490 nm on a microplate reader. Absorbance values were normalized as a percentage of untreated cells (set at 100%).

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Anchorage-Independent Cell Growth Assay [3]
Cells (8 × 103) were suspended in 1 mL RPMI-1640/10% FBS/0.33% agar with vehicle, gefitinib, a p38 MAPK inhibitor (either SB203580 or Losmapimod), or a combination of gefitinib and p38 MAPK inhibitor and plated on 3 mL solidified RPMI-1640/10% FBS/0.5% agar with the same concentration of vehicle, SB203580, losmapimod and/or gefitinib in each well of 6-well plates in triplicates and cultured for 3 weeks. Images from 5 independent fields of each well were captured by a microscope using Images-Pro Plus software. Colony numbers > 200 pixels were quantified by Image J software.

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1. Cell viability assay: Gefitinib-resistant NSCLC cells (H1975GR and PC9GR) were seeded in 96-well plates at a density of 5×10³ cells per well and incubated overnight. Different concentrations of Losmapimod (0.1 μM, 1 μM, 10 μM) were added to the wells, and the cells were incubated for 72 hours. After incubation, MTT reagent (5 mg/mL) was added to each well, and the plates were incubated for another 4 hours. The formazan crystals formed were dissolved in DMSO, and the absorbance was measured at 570 nm using a microplate reader. Cell viability was calculated as the percentage of absorbance in the treated group compared to the control group [3]
2. Western blot analysis: Gefitinib-resistant NSCLC cells were treated with Losmapimod (1 μM) for 24 hours. The cells were harvested and lysed in RIPA buffer containing protease and phosphatase inhibitors. The protein concentration of the cell lysates was determined using a BCA protein assay kit. Equal amounts of protein (30 μg) were separated by SDS-PAGE and transferred to PVDF membranes. The membranes were blocked with 5% non-fat milk for 1 hour at room temperature, then incubated with primary antibodies against p-p38, p38, p-HSP27, HSP27, p-MAPKAPK2, MAPKAPK2, and β-actin overnight at 4°C. After washing with TBST, the membranes were incubated with horseradish peroxidase-conjugated secondary antibodies for 1 hour at room temperature. The protein bands were visualized using an enhanced chemiluminescence detection system, and the band intensities were quantified using ImageJ software [3]
3. Flow cytometry analysis for tetraploidy: Gefitinib-resistant NSCLC cells were treated with Losmapimod (1 μM) for 48 hours. The cells were harvested, washed with PBS, and fixed with 70% ethanol at -20°C overnight. After fixation, the cells were washed with PBS and stained with propidium iodide (PI) solution (containing RNase A) for 30 minutes at room temperature in the dark. The DNA content of the cells was analyzed using a flow cytometer, and the percentage of tetraploid cells (4N) was calculated using flow cytometry analysis software [3]
4. Clone formation assay: Gefitinib-resistant NSCLC cells were seeded in 6-well plates at a density of 200 cells per well and incubated overnight. The cells were then treated with Losmapimod (0.1 μM, 1 μM) for 14 days, with the medium containing the drug changed every 3 days. After 14 days, the cells were fixed with methanol and stained with crystal violet solution. The number of clones (containing more than 50 cells) was counted under a microscope, and the cloning efficiency was calculated as the percentage of clones formed compared to the control group [3]

Male SHR-SPs (n=70) were divided into five groups (n=14 per group) based on body weight and randomly assigned to one of five diets: normal diet controls (ND), high salt-fat diet controls (SFD), SFD + GSK-AHAB (1.2 mg/kg/day), and SFD + GSK-AHAB (12 mg/kg/day) and SFD + MK 966 (18 mg/kg/day). All medications are taken orally by mixing with SFD. The conscious measurement of mean arterial blood pressure and heart rate is performed on a subgroup of animals from each group (n=6 per group) who have undergone anesthesia and have been surgically outfitted with radiotelemetry devices. Before the study begins, these animals are given at least 7 days to recover.

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The in vivo Gefitinib-Resistant NSCLC PDX Model [3]
Previously, an in vivo gefitinib-resistant NSCLC PDX model was generated in-house (Zhang et al., 2015). The gefitinib-resistant tumor fragments were passaged to 40 mice for an in vivo study. Mice were divided into four groups (n = 10 mice per group). The four groups were: 1) vehicle control; 2) 50 mg/kg gefitinib; 3) 12 mg/kg Losmapimod; and 4) 50 mg/kg gefitinib and 12 mg/kg Losmapimod (Willette et al., 2009). Once the tumor volumes reached approximately 25 mm3, mice were treated by oral gavage with vehicle control (dimethyl sulfoxide 5%, normal saline 50% and PEG400 50%), gefitinib and/or Losmapimod. Body weights and tumor measurements were performed twice a week and tumor volume was calculated based on the formula: length × width2 × 0.5. At the end of the experiment, mice were sacrificed prior to removal of the tumors for further analysis.

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1. Nude mouse xenograft model establishment: Female BALB/c nude mice (6-8 weeks old) were subcutaneously injected with 5×10⁶ H1975GR cells (suspended in 100 μL of PBS mixed with Matrigel at a 1:1 ratio) into the right flank. When the tumor volume reached approximately 100 mm³, the mice were randomly divided into two groups (n=6 per group): the vehicle control group and the Losmapimod-treated group [3]
2. Drug administration: Losmapimod was dissolved in a vehicle consisting of 10% DMSO, 40% PEG300, and 50% saline. The Losmapimod-treated group received intraperitoneal injections of Losmapimod at a dose of 10 mg/kg once daily for 21 days. The vehicle control group received intraperitoneal injections of the same volume of vehicle according to the same schedule [3]
3. Tumor and mouse monitoring: During the treatment period, the tumor volume was measured every 3 days using a vernier caliper, and the tumor volume was calculated using the formula: Tumor volume (mm³) = (length × width²)/2. The body weight of the mice was also measured every 3 days to monitor potential toxicity. After the treatment, the mice were euthanized, and the tumors were excised, weighed, and stored at -80°C for subsequent immunohistochemical analysis [3]

This Phase I study aimed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of single and repeated oral administration of lopapimoxine and its metabolite GSK198602 in healthy Japanese volunteers. Participants (n = 41) received a single oral dose of lopapimoxine (2.5, 7.5, or 20 mg) or a matched placebo for 3 consecutive days (n = 20); or twice daily lopapimoxine 7.5 mg or a matched placebo for 14 days (n = 21). Assessment endpoints included maximum plasma concentration (Cmax), time to peak concentration (Tmax), apparent terminal half-life (t1/2), area under the curve (AUC), and changes in C-reactive protein and phosphorylated heat shock protein 27 levels. No serious adverse events occurred during the study, and no safety issues were observed in clinical laboratory parameters, 12-lead electrocardiograms, or vital signs. The time to peak concentration (Tmax) of lopapimod is 3–4 hours, and the mean half-life (t1/2) is approximately 7.9–9.0 hours. There were no significant differences in Tmax and apparent clearance after oral administration among different dosing regimens. Healthy Japanese volunteers tolerated lopapimod well with single and repeated oral administration. GSK198602 had a similar Tmax to lopapimod, but a slightly longer half-life. After a single dose, the AUC of both lopapimod and GSK198602 increased proportionally to the dose. After repeated administration, the trough concentration reached steady state within 2 days, with cumulative ratios of 1.56 for lopapimod and 1.91 for GSK198602.
Reference: Clin Pharmacol Drug Dev. 2015 Jul;4(4):262-9. https://pubmed.ncbi.nlm.nih.gov/27136906/

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Objective: To evaluate the safety, tolerability, pharmacokinetics (PK) and target binding (TE) of lopinatomegalomod in blood and muscle of patients with facioscapulohumeral muscular dystrophy (FSHD). Methods: This study consisted of Part A: 10 healthy volunteers were randomized to receive a single oral dose of lopapimod (7.5 mg, then 15 mg; n = 8) or placebo (two phases; n = 2); Part B: 15 patients with FSHD were randomized to receive placebo (n = 3), lopapimod 7.5 mg (n = 6), or lopapimod 15 mg (n = 6); Part C: FSHD patients received open-label lopapimod 15 mg twice daily for 14 days (n = 5). At baseline and on day 14, biopsies were performed on FSHD patients to obtain normal muscle tissue as shown by magnetic resonance imaging (Part B) and affected muscle tissue identified by anomalous short-time inversion recovery sequence (STIR) (Part C). Pharmacokinetics (PK) and therapeutic effects (TE) in muscle and sorbitol-stimulated blood were assessed based on the pHSP27 to total HSP27 ratio. Results: The pharmacokinetic (PK) characteristics were similar in healthy volunteers and FSHD patients. In FSHD patients (Part B), the mean Cmax and AUC0-12 after administration of 15 mg were 85.0 ± 16.7 ngh/mL and 410 ± 50.3 ngh/mL, respectively. PK results were similar in Parts B and C, with the results for 7.5 mg being approximately dose-proportional to those for 15 mg. A dose-dependent effect was observed in muscle concentrations (42.1 ± 10.5 ng/g [7.5 mg] to 97.2 ± 22.4 ng/g [15 mg]), with the plasma/muscle concentration ratio reaching peak concentration (tmax) at approximately 3.5 hours post-administration, ranging from approximately 0.67 to 1. TE effects were observed in both blood and muscle. Adverse events (AEs) were mild and resolved spontaneously. Conclusion: Lomapimo was well tolerated, and no serious adverse events occurred. Dose-dependent pharmacokinetics (PK) and drug effects were observed. This study supports advancing lopapimido to a Phase II clinical trial for facioscapulohumeral muscular dystrophy (FSHD).
Reference: Br J Clin Pharmacol. 2021 Dec;87(12):4658-4669. https://pubmed.ncbi.nlm.nih.gov/33931884/

Objective: This study aimed to evaluate the safety and tolerability of a single intravenous infusion of the p38 mitogen-activated protein kinase inhibitor locapimod, with the goal of rapidly achieving therapeutic concentrations for potential use in acute coronary syndrome. Pharmacokinetics (PK) following intravenous administration was characterized, and the pharmacokinetic/pharmacodynamic (PK/PD) relationship between locapimod and phosphorylated heat shock protein 27 (pHSP27) and high-sensitivity C-reactive protein was investigated. Methods: Healthy volunteers received either a 1 mg intravenous infusion of locapimod (15 minutes, n = 4) or a 3 mg intravenous infusion of locapimod (15 minutes followed by a washout period), followed by an oral 15 mg locapimod (PO, n = 12). Pharmacokinetic parameters were calculated using a non-compartmental model. The PK/PD relationship was investigated using modeling and simulation methods. Results: No deaths, non-fatal serious adverse events, or adverse events leading to discontinuation of the drug occurred. Headache was the only adverse event reported more than once (n = 3 after oral administration). Following intravenous administration of 3 mg and oral administration of 15 mg, the Cmax was 59.4 and 45.9 μg/L, respectively, and the AUC0-∞ was 171.1 and 528.0 μg/L, respectively. The absolute oral bioavailability was 0.62 [90% confidence interval (CI) 0.56, 0.68]. The maximum reduction in pHSP27 after intravenous administration of 3 mg and oral administration of 15 mg was 44% (95% CI 38%, 50%) and 55% (95% CI 50%, 59%), respectively, occurring at 30 minutes and 4 hours, respectively. Twenty-four hours after oral administration, high-sensitivity C-reactive protein levels decreased by 17% (95% CI 9%, 24%). A direct-linked maximal inhibitory effect model showed a correlation between plasma concentration and pHSP27 concentration. Conclusion: In healthy volunteers, a single intravenous infusion of lopapimod is safe and well-tolerated and may be used as an initial loading dose for acute coronary syndrome due to its rapid onset of action. Reference: Br J Clin Pharmacol. 2013 Jul;76(1):99-106. https://pubmed.ncbi.nlm.nih.gov/23215699/ 1. In a nude mouse xenograft model, lopapimod (10 mg/kg, intraperitoneal injection, once daily for 21 days) did not cause significant changes in mouse body weight. The body weight of mice in the treatment group was comparable to that of the vector control group throughout the treatment period [3] 2. No obvious toxic reactions (such as somnolence, loss of appetite or abnormal behavior) were observed in mice in the lopapimod treatment group during the experiment [3] 3. No data on plasma protein binding rate (LD50) or drug interaction of lopapimod were provided in the literature [3]

[1]. Differential effects of p38 mitogen-activated protein kinase and cyclooxygenase 2 inhibitors in a model of cardiovascular disease. J Pharmacol Exp Ther. 2009 Sep;330(3):964-70.

[2]. DUX4 expression activates JNK and p38 MAP kinases in myoblasts. Dis Model Mech. 2022 Nov 1;15(11):dmm049516.

[3]. Losmapimod Overcomes Gefitinib Resistance in Non-small Cell Lung Cancer by Preventing Tetraploidization. eBioMedicine. 2018 Feb 2;28:51–61.

6-[5-[(cyclopropylamino)-oxymethyl]-3-fluoro-2-methylphenyl]-N-(2,2-dimethylpropyl)-3-pyridinecarboxamide is a phenylpyridine compound. Lomapimod has been investigated for the prevention of chronic obstructive pulmonary disease. Lomapimod is an orally bioavailable inhibitor of p38 mitogen-activated protein kinase (MAPK) α and β isoforms with potential immunomodulatory and anti-inflammatory activities. Oral administration of lomapimod inhibits the activity of p38α/β MAPK, thereby blocking p38α/β MAPK-mediated signal transduction. This may lead to the suppression of the production of pro-inflammatory cytokines. p38 MAPK is a serine/threonine protein kinase that plays an important role in regulating the transcription and translation of inflammation-related cytokines, including tumor necrosis factor-α (TNF-α) and interleukins (IL)-1, IL-6, and IL-8.

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Abundant evidence suggests that inflammation plays a significant role in cardiovascular disease; however, the long-term efficacy of anti-inflammatory drugs in treating these diseases is less than satisfactory. A recent study compared the effects of two anti-inflammatory drugs [cyclooxygenase 2 (COX2) inhibitors and p38 inhibitors] in a cardiovascular disease model. In spontaneously hypertensive stroke-prone rats (SHR-SP), the effects of 4-(4-methylsulfonylphenyl)-3-phenyl-5H-furan-2-one (rofecoxib; a COX2 inhibitor) and 6-{5-[(cyclopropylamino)carbonyl]-3-fluoro-2-methylphenyl}-N-(2,2-dimethylpropyl)-3-pyridinecarboxamide [GSK-AHAB, a selective p38 mitogen-activated protein kinase (MAPK) inhibitor] on blood vessels, kidneys, and heart were investigated. In spontaneously hypertensive rats (SHR-SP) fed a high-salt, high-fat diet (SFD), long-term treatment with GlaxoSmithKline avanafil (GSK-AHAB) significantly and dose-dependently improved survival, endothelium-dependent and non-endothelium-dependent vasodilation, and renal function indicators, and reduced dyslipidemia, hypertension, cardiac remodeling, plasma renin activity (PRA), aldosterone, and interleukin-1β (IL-1β) levels. Conversely, long-term COX2-selective rofecoxib treatment exacerbated the harmful effects of SFD, namely increased vascular and renal dysfunction, dyslipidemia, hypertension, cardiac hypertrophy, PRA, aldosterone, and IL-1β levels. The protective effect of p38 MAPK inhibitors differed significantly from the harmful effects of selective COX2 inhibitors in SHR-SP, suggesting that anti-inflammatory drugs may have different roles in cardiovascular disease. These findings also suggest a method for assessing long-term cardiovascular efficacy and safety. [1]

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Fascioscapulohumeral muscular dystrophy (FSHD) is caused by the aberrant expression of the DUX4 transcription factor in skeletal muscle, leading to transcriptional alterations, phenotypic abnormalities, and cell death. To gain a deeper understanding of the dynamics of DUX4-induced stress, we activated DUX4 expression in myoblasts and performed longitudinal RNA sequencing, combined with proteomics and phosphoproteomics analysis. This analysis revealed changes in cellular physiology following DUX4 activation, including DNA damage and alterations in mRNA splicing. Phosphoproteomics analysis revealed rapid and widespread changes in protein phosphorylation following DUX4 induction, suggesting that alterations in kinase signaling may play a role in DUX4-mediated stress and cell death. In fact, we demonstrated that two stress-responsive MAP kinase pathways, JNK and p38, are activated upon DUX4 expression. Inhibition of either of these pathways alleviated DUX4-mediated myoblast death. These findings reveal that the JNK pathway is involved in DUX4-mediated cell death and provide new insights into the role of the p38 pathway (a clinical therapeutic target for FSHD). [2]

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Epidermal growth factor receptor (EGFR) plays a crucial role in non-small cell lung cancer (NSCLC). Constitutively activated EGFR mutations, including in-frame deletions in exon 19 and point mutations in exon 21 L858R, account for approximately 90% of all EGFR activating mutations in NSCLC. Although oral EGFR tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, have shown significant clinical efficacy and significantly prolonged progression-free survival in patients carrying these EGFR activating mutations, most of these patients eventually develop acquired resistance. Researchers have recently listed genomic instability as one of the hallmark features of cancer. Genomic instability often involves transient phases of polyploidy, especially tetraploidy. Tetraploid cells can undergo asymmetric cell division or chromosome loss, leading to tumor heterogeneity and multidrug resistance. Therefore, identifying the signaling pathways involved in tetraploidization is crucial for overcoming drug resistance. In this study, we found that gefitinib activates the YAP-MKK3/6-p38 MAPK-STAT3 signaling pathway and induces tetraploidization in gefitinib-resistant cells. Using the p38 MAPK inhibitors SB203580 and losmapimod, we were able to eliminate gefitinib-induced tetraploidization, thereby overcoming gefitinib resistance. Furthermore, knocking down p38α MAPK using the shRNA approach prevented tetraploidization and significantly inhibited cancer cell growth. Finally, in an in vivo study, lopapimod successfully overcame gefitinib resistance using our self-established patient-derived xenograft (PDX) mouse model. Overall, these findings suggest that lopapimod may be a potential clinical drug for overcoming gefitinib resistance in non-small cell lung cancer (NSCLC). [3]

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1. Lomapimod overcomes gefitinib resistance in NSCLC by inhibiting tetraploidization through the p38 MAPK signaling pathway. In gefitinib-resistant NSCLC cells, activation of p38 MAPK promotes tetraploidization, and locapimod inhibits this process by blocking p38 MAPK activity, thereby restoring the sensitivity of NSCLC cells to gefitinib. [3]
2. Gefitinib resistance in NSCLC is often associated with tetraploid formation, which leads to genomic instability and resistance. Lomapimod targets this mechanism by inhibiting tetraploidization, providing a potential therapeutic strategy for treating gefitinib-resistant non-small cell lung cancer. [3]

C22H26FN3O2

383.46

383.2

C, 68.91; H, 6.83; F, 4.95; N, 10.96; O, 8.34

585543-15-3

11552706

white solid powder

1.2±0.1 g/cm3

529.4±50.0 °C at 760 mmHg

274.0±30.1 °C

0.0±1.4 mmHg at 25°C

1.582

3.3

2

4

6

28

573

0

FC1C(C([H])([H])[H])=C(C2C([H])=C([H])C(=C([H])N=2)C(N([H])C([H])([H])C(C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H])=O)C([H])=C(C=1[H])C(N([H])C1([H])C([H])([H])C1([H])[H])=O

KKYABQBFGDZVNQ-UHFFFAOYSA-N

InChI=1S/C22H26FN3O2/c1-13-17(9-15(10-18(13)23)21(28)26-16-6-7-16)19-8-5-14(11-24-19)20(27)25-12-22(2,3)4/h5,8-11,16H,6-7,12H2,1-4H3,(H,25,27)(H,26,28)

6-[5-(cyclopropylcarbamoyl)-3-fluoro-2-methylphenyl]-N-(2,2-dimethylpropyl)pyridine-3-carboxamide

GW856553; Losmapimod; GSKAHAB; GW856553X; GW-856553; GW 856553, GSK-AHAB; GSK AHAB; GW-856553X; GW 856553X; SB856553; SB-856553; SB 856553

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: 2.75 mg/mL (7.17 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.75 mg/mL (7.17 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.75 mg/mL (7.17 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 27.5 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 2.5 mg/mL (6.52 mM) in 10% EtOH + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear EtOH stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix well.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 5: ≥ 2.5 mg/mL (6.52 mM) (saturation unknown) in 10% EtOH + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear EtOH stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 6: 4% DMSO+30% PEG 300+5% Tween 80+ddH2O: 5mg/mL

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 (Please use freshly prepared in vivo formulations for optimal results.)