Nintedanib Inhibits Wnt3a-Induced Myofibroblast Activation by Suppressing the Src/β-Catenin Pathway

Evaluation of nintedanib efficacy: Attenuating the lens fibrosis in vitro and vivo

PURPOSE

Organ fibrosis is a huge challenge in clinic. There are no drugs for fibrotic cataracts treatments in clinic. Nintedanib is approved by the FDA for pulmonary fibrosis treatments. This study aims to investigate the efficacy and mechanism of nintedanib on fibrotic cataracts.

METHODS

Drug efficacy was validated through TGFβ2-induced cell models and injury-induced anterior subcapsular cataract (ASC) mice. A slit lamp and the eosin staining technique were applied to access the degree of capsular fibrosis. The CCK-8 assay was used to evaluate the toxicity and anti-proliferation ability of the drug. The cell migration was determined by wound healing assay and transwell assay. The anti-epithelial mesenchymal transition (EMT) and anti-fibrosis efficacy were evaluated by qRT-PCR, immunoblot, and immunofluorescence. The inhibition of nintedanib to signaling pathways was certified by immunoblot.

RESULTS

Nintedanib inhibited the migration and proliferation of TGFβ2-induced cell models. Nintedanib can also repress the EMT and fibrosis of the lens epithelial cells. The intracameral injection of nintedanib can also allay the anterior subcapsular opacification in ASC mice. The TGFβ2/ Smad and non-Smad signaling pathways can be blocked by nintedanib in vitro and in vivo.

CONCLUSION

Nintedanib alleviates fibrotic cataracts by suppressing the TGFβ2/ Smad and non-Smad signaling pathways. Nintedanib is a potential drug for lens fibrosis.

A systematic review of the research progress of traditional Chinese medicine against pulmonary fibrosis: from a pharmacological perspective

Pulmonary fibrosis is a chronic progressive interstitial lung disease caused by a variety of etiologies. The disease can eventually lead to irreversible damage to the lung tissue structure, severely affecting respiratory function and posing a serious threat to human health. Currently, glucocorticoids and immunosuppressants are the main drugs used in the clinical treatment of pulmonary fibrosis, but their efficacy is limited and they can cause serious adverse effects. Traditional Chinese medicines have important research value and potential for clinical application in anti-pulmonary fibrosis. In recent years, more and more scientific researches have been conducted on the use of traditional Chinese medicine to improve or reduce pulmonary fibrosis, and some important breakthroughs have been made. This review paper systematically summarized the research progress of pharmacological mechanism of traditional Chinese medicines and their active compounds in improving or reducing pulmonary fibrosis. We conducted a systematic search in several main scientific databases, including PubMed, Web of Science, and Google Scholar, using keywords such as idiopathic pulmonary fibrosis, pulmonary fibrosis, interstitial pneumonia, natural products, herbal medicine, and therapeutic methods. Ultimately, 252 articles were included and systematically evaluated in this analysis. The anti-fibrotic mechanisms of these traditional Chinese medicine studies can be roughly categorized into 5 main aspects, including inhibition of epithelial-mesenchymal transition, anti-inflammatory and antioxidant effects, improvement of extracellular matrix deposition, mediation of apoptosis and autophagy, and inhibition of endoplasmic reticulum stress. The purpose of this article is to provide pharmaceutical researchers with information on the progress of scientific research on improving or reducing Pulmonary fibrosis with traditional Chinese medicine, and to provide reference for further pharmacological research.

Infliximab substantially re-silenced Wnt/β-catenin signaling and ameliorated doxorubicin-induced cardiomyopathy in rats

The release of inflammatory cytokines, namely tumor necrosis factor-α (TNF-α), plays an important role in the pathogenesis of cardiomyopathy. TNF-α increases in plasma and in myocardium of heart failure patients. We aimed to investigate the role of TNF-α inhibitor (infliximab; IFX) in regulating dilated cardiomyopathy (DCM) induced in rats. DCM was induced in rats by doxorubicin (DOX; 3.5 mg. kg-1 , i.p) twice weekly for 3 weeks (21 mg. kg-1 cumulative dose). DCM rats were treated with RPL (1 mg. kg-1 orally, daily), IFX (5 mg. kg-1 ; i.p. once) or their combination for 4 weeks starting next day of last DOX dose. Echocardiography was conducted followed by a collection of blood and left ventricle (LV) for biochemical and histological investigations. DCM rats revealed deteriorated cardiac function (increased CK-MB activity, LVIDs, LVIDd, ESV, and EDV, while decreased EF% and FS%), hypertrophy (increased HW/TL, β-MHC, and α-actin), inflammation (increased IL-1β, IL-6, and TNF-α). The activation of Wnt/β-catenin along with increased gene expression of RAS components (RENIN, ACE, and AT1) were evident. LV architecture also revealed abnormalities and some degree of fibrosis. Treatment with RPL and/or IFX suppressed TNF-α and consequently improved most of these parameters suppressing Wnt/β-catenin/RAS axis. Combined RPL and IFX treatment was the best among all treatments. In conclusion, Wnt/β-catenin/RAS axis is implicated in DOX-induced cardiomyopathy. The upstream TNF-α was proved for the first time in-vivo to stimulate this axis where its inhibition by RPL or IFX prevented DCM. Targeting this axis at two points using RPL and IFX showed better therapeutic efficacy.

Anti-fibrotic strategies and pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) results from the dysregulated process of injury and repair, which promotes scarring of the lung tissue and deposition of collagen-rich extracellular matrix (ECM) components, that make the lung unphysiologically stiff. IPF presents a serious concern as its pathogenesis remains elusive, and current anti-fibrotic treatments are only effective in slowing rather than halting disease progression. The IPF disease pathogenesis is incompletely defined, complex and incorporates interplay between different fibrogenesis signaling pathways. Preclinical IPF experimental models used to validate drug candidates present significant limitations in modeling IPF pathobiology, with their limited time frame, simplicity and inaccurate representation of the disease and the mechanical influences of IPF. Potentially more accurate mimetic disease models that capture the cell-cell and cell-matrix interaction, such as 3D cultures, organoids and precision-cut lung slices (PCLS), may yield more meaningful clinical predictions for drug candidates. Recent advances in developing anti-fibrotic compounds have positioned drug towards targeting components of the fibrogenesis signaling pathway of IPF or the extracellular microenvironment. The major goals in this area of research focus on finding ways to reverse or halt the disease progression by utilizing more disease-relevant experimental models to improve the qualification of potential drug targets for treating pulmonary fibrosis.

TRAF6 Suppresses the Development of Pulmonary Fibrosis by Attenuating the Activation of Fibroblasts

Pulmonary fibrosis (PF) has a high mortality rate, and its pathogenesis is unknown. TNF receptor-associated factor 6 (TRAF6), a signal transducer for inflammatory signaling, plays crucial roles in the pathogenesis of immune diseases. However, its function in PF remains unknown. Herein, we demonstrated that lungs from mice with bleomycin (BLM)-induced PF were characterized by decreased expression of TRAF6 in lung fibroblasts. Enhancing TRAF6 expression protected mice from BLM-induced PF coupled with a significant reduction in fibroblast differentiation. Furthermore, we demonstrated that overexpression of TRAF6 reversed the activation of myofibroblasts from PF mice by reducing the expression of Wnt3a and subsequently suppressing Wnt/β-catenin signaling. Additionally, the abundance of Tribbles pseudokinase 3 (TRIB3), a stress sensor, was negatively correlated with the abundance of TRAF6 in lung fibroblasts. TRIB3 overexpression decreased TRAF6 abundance by reducing TRAF6 stability in lung fibroblasts during PF. Mechanistic studies revealed that TRIB3 bound to TRAF6 and accelerated basal TRAF6 ubiquitination and degradation. Collectively, our data indicate that reduced TRAF6 expression in fibroblasts is essential for the progression of PF, and therefore, genetically increasing TRAF6 expression or disrupting the TRIB3-TRAF6 interaction could be potential therapeutic strategies for fibroproliferative lung diseases in clinical settings.

Cross-Talk between Wnt Signaling and Src Tyrosine Kinase

Src, a non-receptor tyrosine kinase, was first discovered as a prototype oncogene and has been shown to critical for cancer progression for a variety of tissues. Src activity is regulated by a number of post-translational modifications in response to various stimuli. Phosphorylations of Src Tyr419 (human; 416 in chicken) and Src Tyr530 (human; 527 in chicken) have been known to be critical for activation and inactivation of Src, respectively. Wnt signaling regulates a variety of cellular functions including for development and cell proliferation, and has a role in certain diseases such as cancer. Wnt signaling is carried out through two pathways: β-catenin-dependent canonical and β-catenin-independent non-canonical pathways as Wnt ligands bind to their receptors, Frizzled, LRP5/6, and ROR1/2. In addition, many signaling components including Axin, APC, Damm, Dishevelled, JNK kinase and Rho GTPases contribute to these canonical and non-canonical Wnt pathways. However, the communication between Wnt signaling and Src tyrosine kinase has not been well reviewed as Src regulates Wnt signaling through LRP6 tyrosine phosphorylation. GSK-3β phosphorylated by Wnt also regulates Src activity. As Wnt signaling and Src mutually regulate each other, it is noted that aberrant regulation of these components give rise to various diseases including typically cancer, and as such, merit a closer look.

Nintedanib and Dasatinib Treatments Induce Protective Autophagy as a Potential Resistance Mechanism in MPM Cells

Malignant pleural mesothelioma (MPM) is a rare type of cancer with a grim prognosis. So far, no targetable oncogenic mutation was identified in MPM and biomarkers with predictive value toward drug sensitivity or resistance are also lacking. Nintedanib (BIBF1120) is a small-molecule tyrosine kinase inhibitor that showed promising efficacy preclinically and in phase II trial in MPM as an angiogenesis inhibitor combined with chemotherapy. However, the extended phase III trial failed. In this study, we investigated the effect of nintedanib on one of its targets, the SRC kinase, in two commercial and six novel MPM cell lines. Surprisingly, nintedanib treatment did not inhibit SRC activation in MPM cells and even increased phosphorylation of SRC in several cell lines. Combination treatment with the SRC inhibitor dasatinib could reverse this effect in all cell lines, however, the cellular response was dependent on the drug sensitivity of the cells. In 2 cell lines, with high sensitivity to both nintedanib and dasatinib, the drug combination had no synergistic effect but cell death was initiated. In 2 cell lines insensitive to nintedanib combination treatment reduced cell viability synergisticaly without cell death. In contrast, in these cells both treatments increased the autophagic flux assessed by degradation of the autophagy substrate p62 and increased presence of LC3B-II, increased number of GFP-LC3 puncta and decreased readings of the HiBiT-LC3 reporter. Additionaly, autophagy was synergistically promoted by the combined treatment. At the transcriptional level, analysis of lysosomal biogenesis regulator Transcription Factor EB (TFEB) showed that in all cell lines treated with nintedanib and to a lesser extent, with dasatinib, it became dephosphorylated and accumulated in the nucleus. Interestingly, the expression of certain known TFEB target genes implicated in autophagy or lysosomal biogenesis were significantly modified only in 1 cell line. Finally, we showed that autophagy induction in our MPM cell lines panel by nintedanib and dasatinib is independent of the AKT/mTOR and the ERK pathways. Our study reveals that autophagy can serve as a cytoprotective mechanism following nintedanib or dasatinib treatments in MPM cells.

Silibinin Suppresses Tumor Cell-Intrinsic Resistance to Nintedanib and Enhances Its Clinical Activity in Lung Cancer

The anti-angiogenic agent nintedanib has been shown to prolong overall and progression-free survival in patients with advanced non-small-cell lung cancer (NSCLC) who progress after first-line platinum-based chemotherapy and second-line immunotherapy. Here, we explored the molecular basis and the clinical benefit of incorporating the STAT3 inhibitor silibinin-a flavonolignan extracted from milk thistle-into nintedanib-based schedules in advanced NSCLC. First, we assessed the nature of the tumoricidal interaction between nintedanib and silibinin and the underlying relevance of STAT3 activation in a panel of human NSCLC cell lines. NSCLC cells with poorer cytotoxic responses to nintedanib exhibited a persistent, nintedanib-unresponsive activated STAT3 state, and deactivation by co-treatment with silibinin promoted synergistic cytotoxicity. Second, we tested whether silibinin could impact the lysosomal sequestration of nintedanib, a lung cancer cell-intrinsic mechanism of nintedanib resistance. Silibinin partially, but significantly, reduced the massive lysosomal entrapment of nintedanib occurring in nintedanib-refractory NSCLC cells, augmenting the ability of nintedanib to reach its intracellular targets. Third, we conducted a retrospective, observational multicenter study to determine the efficacy of incorporating an oral nutraceutical product containing silibinin in patients with NSCLC receiving a nintedanib/docetaxel combination in second- and further-line settings (n = 59). Overall response rate, defined as the combined rates of complete and partial responses, was significantly higher in the study cohort receiving silibinin supplementation (55%) than in the control cohort (22%, p = 0.011). Silibinin therapy was associated with a significantly longer time to treatment failure in multivariate analysis (hazard ratio 0.43, p = 0.013), despite the lack of overall survival benefit (hazard ratio 0.63, p = 0.190). Molecular mechanisms dictating the cancer cell-intrinsic responsiveness to nintedanib, such as STAT3 activation and lysosomal trapping, are amenable to pharmacological intervention with silibinin. A prospective, powered clinical trial is warranted to confirm the clinical relevance of these findings in patients with advanced NSCLC.

Wnt3a upregulation is involved in TGFβ1-induced cardiac hypertrophy

Pathological cardiac hypertrophy, characterized by enlarged cell size and fetal gene reactivation, ultimately leads to cardiac dysfunction and heart failure. The expression of transforming growth factor beta 1 (TGFβ1) is often elevated in experimental models of cardiac hypertrophy. In the present study, we observed the activation of Wnt/β-catenin signaling in TGFβ1-induced cardiac hypertrophy. TGFβ1 stimulation decreased the phosphorylation levels of β-catenin and triggered the nuclear accumulation of β-catenin. In turn, TGFβ1 enhanced the expression of c-Myc, which is a transcriptional target of canonical Wnt/β-catenin pathway. Knockdown of β-catenin completely blocked TGFβ1-induced c-Myc upregulation. Wnt3a is an important Wnt ligand associated with cardiac fibrosis and hypertrophy. Further investigation revealed that TGFβ1 can upregulate Wnt3a expression in an ALK5-Smad2/3-dependent manner. A consensus Smad binding sequence is located within the Wnt3a promoter, and TGFβ1 stimulation enhanced recruitment of Smad2/3 onto the Wnt3a promoter. Meanwhile, Wnt3a overexpression also stimulated TGFβ1 expression. Chemical inhibition of Wnt/β-catenin signaling partially attenuated TGFβ1-induced hypertrophic responses. These findings suggest crosstalk between TGFβ1 and canonical Wnt/β-catenin pathways in cardiac hypertrophy.