Dacomitinib, a new pan-EGFR inhibitor, is effective in attenuating pulmonary vascular remodeling and pulmonary hypertension

Advances in HER2-Targeted Therapies: From monoclonal antibodies to dual inhibitors developments in cancer treatment

HER2 receptors, overexpressed in certain human cancers, have drawn significant attention in cancer research due to their correlation with poor survival rates. Researchers have developed monoclonal antibodies like Trastuzumab and Pertuzumab against HER2 receptors, which have proven highly beneficial in cancer therapy. Bispecific antibodies like Zanidatamab and antibody-drug conjugates like T-DM1 have been developed to overcome the resistance associated with monotherapy. Small molecules such as Lapatinib, Neratinib, and Pyrotinib were initially developed for treating breast cancer. However, ongoing research is investigating their potential use in other types of cancer, often in combination with other medications. EGFR/HER2 dual-targeted drugs have overcome drug resistance associated with HER2-targeted monotherapy. This comprehensive review covers the structural characteristics of HER2, the HER family signaling pathway mechanism, recent findings regarding HER2 receptor involvement in various cancers, and diverse HER2-targeted therapies. This information provides a comprehensive understanding of HER2-targeted strategies in the evolving field of cancer treatment.

Is Autophagy Targeting a Valid Adjuvant Strategy in Conjunction with Tyrosine Kinase Inhibitors?

Tyrosine kinase inhibitors (TKIs) represent a relatively large class of small-molecule inhibitors that compete with ATP for the catalytic binding site of tyrosine kinase proteins. While TKIs have demonstrated effectiveness in the treatment of multiple malignancies, including chronic myelogenous leukemia, gastrointestinal tumors, non-small cell lung cancers, and HER2-overexpressing breast cancers, as is almost always the case with anti-neoplastic agents, the development of resistance often imposes a limit on drug efficacy. One common survival response utilized by tumor cells to ensure their survival in response to different stressors, including anti-neoplastic drugs, is that of autophagy. The autophagic machinery in response to TKIs in multiple tumor models has largely been shown to be cytoprotective in nature, although there are a number of cases where autophagy has demonstrated a cytotoxic function. In this review, we provide an overview of the literature examining the role that autophagy plays in response to TKIs in different preclinical tumor model systems in an effort to determine whether autophagy suppression or modulation could be an effective adjuvant strategy to increase efficiency and/or overcome resistance to TKIs.

Transplantation of human endometrial perivascular stem cells with hydroxy saffron yellow A promotes uterine repair in rats

BACKGROUND

Intrauterine adhesions (IUAs) jeopardise uterine function in women, which is a great challenge in the clinic. Previous studies have shown that endometrial perivascular cells (En-PSCs) can improve the healing of scarred uteri and that hydroxysafflor yellow A (HSYA) promotes angiogenesis. The purpose of this study was to observe whether the combination of En-PSCs with HSYA could improve the blood supply and fertility in the rat uterus after full-thickness injury.

METHODS

En-PSCs were sorted by flow cytometry, and the effect of HSYA on the proliferation and angiogenesis of the En-PSCs was detected using CCK-8 and tube formation assays. Based on a previously reported rat IUA model, the rat uteri were sham-operated, spontaneously regenerated, or treated with collagen-loaded PBS, collagen-loaded HSYA, collagen-loaded En-PSCs, or collagen-loaded En-PSCs with HSYA, and then collected at both 30 and 90 days postsurgery. HE staining and Masson staining were used to evaluate uterine structure and collagen fibre deposition, and immunohistochemical staining for α-SMA and vWF was used to evaluate myometrial regeneration and neovascularization in each group. A fertility assay was performed to detect the recovery of pregnancy function in each group. RNA-seq was performed to determine the potential mechanism underlying En-PSCs/HSYA treatment. Immunofluorescence, tube formation assays, and Western blot were used to validate the molecular mechanism involved.

RESULTS

The transplantation of Collagen/En-PSCs/HSYA markedly promoted uterine repair in rats with full-thickness injury by reducing fibrosis, increasing endometrial thickness, regenerating myometrium, promoting angiogenesis, and facilitated live births. RNA sequencing results suggested that En-PSCs/HSYA activated the NRG1/ErbB4 signaling pathway. In vitro tube formation experiments revealed that the addition of an ErbB inhibitor diminished the tube formation ability of cocultured En-PSCs and HUVECs. Western blot results further showed that elevated levels of NRG1 and ErbB4 proteins were detected in the Collagen/En-PSCs/HSYA group compared to the Collagen/En-PSCs group. These collective results suggested that the beneficial effects of the transplantation of Collagen/En-PSCs/HSYA might be attributed to the modulation of the NRG1/ErbB4 signaling pathway.

CONCLUSIONS

The combination of En-PSCs/HSYA facilitated morphological and functional repair in rats with full-thickness uterine injury and may promote endometrial angiogenesis by regulating the NRG1/ErbB4 signaling pathway.

Unveiling the dual role of autophagy in vascular remodelling and its related diseases

Vascular remodelling is an adaptive response to physiological and pathological stimuli that leads to structural and functional changes in the vascular intima, media, and adventitia. Pathological vascular remodelling is a hallmark feature of numerous vascular diseases, including atherosclerosis, hypertension, abdominal aortic aneurysm, pulmonary hypertension and preeclampsia. Autophagy is critical in maintaining cellular homeostasis, and its dysregulation has been implicated in the pathogenesis of various diseases, including vascular diseases. However, despite emerging evidence, the role of autophagy and its dual effects on vascular remodelling has garnered limited attention. Autophagy can exert protective and detrimental effects on the vascular intima, media and adventitia, thereby substantially influencing the course of vascular remodelling and its related vascular diseases. Currently, there has not been a review that thoroughly describes the regulation of autophagy in vascular remodelling and its impact on related diseases. Therefore, this review aimed to bridge this gap by focusing on the regulatory roles of autophagy in diseases related to vascular remodelling. This review also summarizes recent advancements in therapeutic agents targeting autophagy to regulate vascular remodelling. Additionally, this review offers an overview of recent breakthroughs in therapeutic agents targeting autophagy to regulate vascular remodelling. A deeper understanding of how autophagy orchestrates vascular remodelling can drive the development of targeted therapies for vascular diseases.

Traditional Chinese medicine monomers: Targeting pulmonary artery smooth muscle cells proliferation to treat pulmonary hypertension

Pulmonary hypertension (PH) is a complex multifactorial disease characterized by increased pulmonary vascular resistance and pulmonary vascular remodeling (PVR), with high morbidity, disability, and mortality. The abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is the main pathological change causing PVR. At present, clinical treatment drugs for PH are limited, which can only improve symptoms and reduce hospitalization but cannot delay disease progression and reduce survival rate. In recent years, numerous studies have shown that traditional Chinese medicine monomers (TCMs) inhibit excessive proliferation of PASMCs resulting in alleviating PVR through multiple channels and multiple targets, which has attracted more and more attention in the treatment of PH. In this paper, the experimental evidence of inhibiting PASMCs proliferation by TCMs was summarized to provide some directions for the future development of these mentioned TCMs as anti-PH drugs in clinical.

Potential Role of Cellular Senescence in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare and chronic lung vasculature disease characterized by pulmonary vasculature remodeling, including abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) and dysfunctional endothelial cells (ECs). Remodeling of the pulmonary vasculature occurs from maturity to senescence, and it has become apparent that cellular senescence plays a central role in the pathogenesis of various degenerative vascular diseases and pulmonary pathologies. Cellular senescence represents a state of stable proliferative arrest accompanied by the senescence-associated secretory phenotype (SASP), which entails the copious secretion of proinflammatory signals in the tissue microenvironment. Evidences show that in PAH patients, higher levels of cytokines, chemokines, and inflammatory mediators can be detected and correlate with clinical outcome. Moreover, senescent cells accrue with age in epithelial, endothelial, fibroblastic, and immunological compartments within human lungs, and evidence showed that ECs and PASMCs in lungs from patients with chronic obstructive pulmonary disease were characterized by a higher number of senescent cells. However, there is little evidence uncovering the molecular pulmonary vasculature senescence in PAH. Herein, we review the cellular senescence in pulmonary vascular remodeling, and emphasize its importance in PAH. We further introduce some signaling pathways which might be involved in vasculature senescence and PAH, with the intent to discuss the possibility of the PAH therapy via targeting cellular senescence and reduce PAH progression and mortality.

Hypoxic pulmonary endothelial cells release epidermal growth factor leading to vascular smooth muscle cell arginase-2 expression and proliferation

The hallmark of pulmonary hypertension (PH) is vascular remodeling. We have previously shown that human pulmonary microvascular endothelial cells (hPMVEC) respond to hypoxia with epidermal growth factor (EGF) mediated activation of the receptor tyrosine kinase, EGF receptor (EGFR), resulting in arginase-2 (Arg2)-dependent proliferation. We hypothesized that the release of EGF by hPMVEC could result in the proliferation of human pulmonary arterial smooth muscle cells (hPASMC) via activation of EGFR on the hPASMC leading to Arg2 up-regulation. To test this hypothesis, we used conditioned media (CM) from hPMVEC grown either in normoxia (NCM) or hypoxia (HCM). Human PASMC were incubated in normoxia with either HCM or NCM, and HCM caused significant induction of Arg2 and viable cell numbers. When HCM was generated with either an EGF-neutralizing antibody or an EGFR blocking antibody the resulting HCM did not induce Arg2 or increase viable cell numbers in hPASMC. Adding an EGFR blocking antibody to HCM, prevented the HCM-induced increase in Arg2 and viable cell numbers. HCM induced robust phosphorylation of hPASMC EGFR. When hPASMC were transfected with siRNA against EGFR the HCM-induced increase in viable cell numbers was prevented. When hPASMC were treated with the arginase antagonist nor-NOHA, the HCM-induced increase in viable cell numbers was prevented. These data suggest that hypoxic hPMVEC releases EGF, which activates hPASMC EGFR leading to Arg2 protein expression and an increase in viable cell numbers. We speculate that EGF neutralizing antibodies or EGFR blocking antibodies represent potential therapeutics to prevent and/or attenuate vascular remodeling in PH associated with hypoxia.

EGR1 Is Implicated in Right Ventricular Cardiac Remodeling Associated with Pulmonary Hypertension

Background: Pulmonary hypertension (PH) is a vasoconstrictive disease characterized by elevated mean pulmonary arterial pressure (mPAP) at rest. Idiopathic pulmonary arterial hypertension (iPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) represent two distinct subtypes of PH. Persisting PH leads to right ventricular (RV) hypertrophy, heart failure, and death. RV performance predicts survival and surgical interventions re-establishing physiological mPAP reverse cardiac remodeling. Nonetheless, a considerable number of PH patients are deemed inoperable. The underlying mechanism(s) governing cardiac regeneration, however, remain largely elusive. Methods: In a longitudinal approach, we profiled the transcriptional landscapes of hypertrophic RVs and recovered hearts 3 months after surgery of iPAH and CTEPH patients. Results: Genes associated with cellular responses to inflammatory stimuli and metal ions were downregulated, and cardiac muscle tissue development was induced in iPAH after recovery. In CTEPH patients, genes related to muscle cell development were decreased, and genes governing cardiac conduction were upregulated in RVs following regeneration. Intriguingly, early growth response 1 (EGR1), a profibrotic regulator, was identified as a major transcription factor of hypertrophic RVs in iPAH and CTEPH. A histological assessment confirmed our biocomputational results, and suggested a pivotal role for EGR1 in RV vasculopathy. Conclusion: Our findings improved our understanding of the molecular events driving reverse cardiac remodeling following surgery. EGR1 might represent a promising candidate for targeted therapy of PH patients not eligible for surgical treatment.

Text Mining-Based Drug Discovery for Connective Tissue Disease–Associated Pulmonary Arterial Hypertension

Background: The current medical treatments for connective tissue disease–associated pulmonary arterial hypertension (CTD-PAH) do not show favorable efficiency for all patients, and identification of novel drugs is desired.

Methods: Text mining was performed to obtain CTD- and PAH-related gene sets, and the intersection of the two gene sets was analyzed for functional enrichment through DAVID. The protein–protein interaction network of the overlapping genes and the significant gene modules were determined using STRING. The enriched candidate genes were further analyzed by Drug Gene Interaction database to identify drugs with potential therapeutic effects on CTD-PAH.

Results: Based on text mining analysis, 179 genes related to CTD and PAH were identified. Through enrichment analysis of the genes, 20 genes representing six pathways were obtained. To further narrow the scope of potential existing drugs, we selected targeted drugs with a Query Score ≥5 and Interaction Score ≥1. Finally, 13 drugs targeting the six genes were selected as candidate drugs, which were divided into four drug–gene interaction types, and 12 of them had initial drug indications approved by the FDA. The potential gene targets of the drugs on this list are IL-6 (one drug) and IL-1β (two drugs), MMP9 (one drug), VEGFA (three drugs), TGFB1 (one drug), and EGFR (five drugs). These drugs might be used to treat CTD-PAH.

Conclusion: We identified 13 drugs targeting six genes that may have potential therapeutic effects on CTD-PAH.

The Roles of S100A4 and the EGF/EGFR Signaling Axis in Pulmonary Hypertension with Right Ventricular Hypertrophy

Pulmonary hypertension (PH) is characterized by increased pulmonary arterial pressure caused by the accumulation of mesenchymal-like cells in the pulmonary vasculature. PH can lead to right ventricular hypertrophy (RVH) and, ultimately, heart failure and death. In PH etiology, endothelial-to-mesenchymal transition (EndMT) has emerged as a critical process governing the conversion of endothelial cells into mesenchymal cells, and S100A4, EGF, and EGFR are implicated in EndMT. However, a potential role of S100A4, EGF, and EGFR in PH has to date not been elucidated. We therefore quantified S100A4, EGF, and EGFR in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH). To determine specificity for unilateral heart disease, the EndMT biomarker signature was further compared between PH patients presenting with RVH and patients suffering from aortic valve stenosis (AVS) with left ventricular hypertrophy. Reduced S100A4 concentrations were found in CTEPH and iPAH patients with RVH. Systemic EGF was increased in CTEPH but not in iPAH, while AVS patients displayed slightly diminished EGF levels. EGFR was downregulated in all patient groups when compared to healthy controls. Longitudinal data analysis revealed no effect of surgical therapies on EndMT markers. Pulmonary thrombo-endarterectomized samples were devoid of S100A4, while S100A4 tissue expression positively correlated with higher grades of Heath–Edwards histopathological lesions of iPAH-derived lung tissue. Histologically, EGFR was not detectable in CTEPH lungs or in iPAH lesions. Together, our data suggest an intricate role for S100A4 and EGF/EGFR in PH with right heart pathology.

Piperlongumine attenuates vascular remodeling in hypoxic pulmonary hypertension by regulating autophagy

OBJECTIVE

The aim of this study was to determine the therapeutic effect of piperlongumine on hypoxic pulmonary hypertension.

METHODS

A hypoxic pulmonary hypertension rat model was constructed, primary rat pulmonary artery smooth muscle cells (PASMCs) were isolated, and the proliferation of PASMCs was measured by Cell Counting Kit‑8 assay. The expression of autophagic proteins microtubule-associated protein 1 light chain 3B (LC3B) and P62 were examined by western blot. Autophagic flux in PASMCs was detected by tandem mRFP-GFP-LC3 fluorescence analysis.

RESULTS

Hypoxia-induced proliferation of PASMCs was significantly inhibited by piperlongumine exposure. Treatment with piperlongumine elevated LC3B II/LC3B I protein ratio and decreased the expression of P62 protein in both PASMCs and rat lung tissues. Tandem mRFP-GFP-LC3 fluorescence analysis showed that piperlongumine increased autophagic flux in PASMCs. Inhibition of autophagy using 3-methyladenine (3-MA) attenuated the inhibitory effect of piperlongumine on proliferation of PASMCs. Chronic hypoxia exposure led to a significant increase in rat right ventricle systolic pressure, right ventricular hypertrophy, wall thickness and area of pulmonary artery, and muscularization of pulmonary arterioles, which was obviously suppressed by administration of piperlongumine. 3-MA attenuated the alleviating effects of piperlongumine on pulmonary vascular remodeling.

CONCLUSIONS

Piperlongumine attenuates vascular remodeling in hypoxic pulmonary hypertension by regulating autophagy. Piperlongumine treatment may serve as a promising therapy for hypoxic pulmonary hypertension.

Effects of dacomitinib on the pharmacokinetics of poziotinib in vivo and in vitro

CONTEXT

Dacomitinib and poziotinib, irreversible ErbB family blockers, are often used for treatment of non-small cell lung cancer (NSCLC) in the clinic.

OBJECTIVE

This study investigates the effect of dacomitinib on the pharmacokinetics of poziotinib in rats.

MATERIALS AND METHODS

Twelve Sprague-Dawley rats were randomly divided into two groups: the test group (20 mg/kg dacomitinib for 14 consecutive days) and the control group (equal amounts of vehicle). Each group was given an oral dose of 10 mg/kg poziotinib 30 min after administration of dacomitinib or vehicle at the end of the 14 day administration. The concentration of poziotinib in plasma was quantified by UPLC-MS/MS. Both in vitro effects of dacomitinib on poziotinib and the mechanism of the observed inhibition were studied in rat liver microsomes and human liver microsomes.

RESULTS

When orally administered, dacomitinib increased the AUC, T_max and decreased CL of poziotinib (p < 0.05). The IC₅₀ values of M1 in RLM, HLM and CYP3A4 were 11.36, 30.49 and 19.57 µM, respectively. The IC₅₀ values of M2 in RLM, HLM and CYP2D6 were 43.69, 0.34 and 0.11 µM, respectively, and dacomitinib inhibited poziotinib by a mixed way in CYP3A4 and CYP2D6. The results of the in vivo experiments were consistent with those of the in vitro experiments.

CONCLUSIONS

This research demonstrates that a drug-drug interaction between poziotinib and dacomitinib possibly exists when readministered with poziotinib; thus, clinicians should pay attention to the resulting changes in pharmacokinetic parameters and accordingly, adjust the dose of poziotinib in clinical settings.

Bioinformatic exploration of the immune related molecular mechanism underlying pulmonary arterial hypertension

This study aimed to explore the molecular mechanisms related to immune and hub genes related to pulmonary arterial hypertension (PAH). The differentially expressed genes (DEGs) of GSE15197 were identified as filters with adjusted P value <0.05, and |Log2 fold change|> 1. Biofunctional and pathway enrichment annotation of DEGs indicated that immunity and inflammation may play an important role in the molecular mechanism of PAH. The CIBERSORT algorithm further analyzed the immune cell infiltration characteristics of the PAH and control samples. Subsequently, 16 hub genes were identified from DEGs using the least absolute shrinkage and selection operator (LASSO) algorithm. An immune related gene CX3CR1 was further selected from the intersection results of the 16 hub genes and the top 20 genes with the most adjacent nodes in the protein-protein interaction (PPI) network. GSE113439, GSE48149, and GSE33463 datasets were used to validate and proved CX3CR1 with a remarkable score of AUC to distinguish PAH samples caused by various reasons from the control group.

Ameliorative Effects and Mechanism of Buyang Huanwu Decoction on Pulmonary Vascular Remodeling: Network and Experimental Analyses

Pulmonary hypertension (PH) is a severe and progressive cardiovascular disease. Its pathological mechanism is complex, and the common pathological feature is pulmonary vascular remodeling. The efficacy of existing therapeutic agents is limited. Traditional Chinese medicine (TCM) has its unique advantages in the prevention and treatment of complex diseases. In this study, the approaches of network pharmacology combined with biological verification are employed to explore the role of Buyang huanwu decoction (BYHWD) in the treatment of PH. The active ingredients in BYHWD were first screened based on the ADME properties of the compounds. In turn, the mean of data mining was utilized to analyze the potential targets of BYHWD for the treatment of PH. On this basis, a series of interaction networks were constructed for searching the core targets. The genes including AKT1, MMP9, NOS3/eNOS, and EGFR were found to be possible key targets in BYHWD. The results of enrichment analysis showed that the targets of BYHWD focused on smooth muscle cell proliferation, migration, and apoptosis, which are classic biological processes involved in pulmonary vascular remodeling and are closely related to the PI3K-Akt-eNOS pathway. The methods of biological experiments were adopted to verify the above results. The present study elucidated the mechanism of BYHWD in the treatment of PH and provided new ideas for the clinical use of TCM in the treatment of PH.

Curcumin Suppresses Epithelial Growth Factor Receptor (EGFR) and Proliferative Protein (Ki 67) in Acute Lung Injury and Lung Fibrosis In vitro and In vivo

BACKGROUND

Acute lung injury is one of the common conditions caused due to bleomycin therapy which leads to pulmonary fibrosis, which is one of the severe interstitial lung diseases most commonly affecting the elderly individuals. EGFR and Ki67 can be marked as beneficial markers for detecting pulmonary fibrosis based on which clinicians can guide the therapy.

OBJECTIVE

The aim of the study was to evaluate the effect of curcumin as an intervention on two prognostic markers EGFR and Ki67 in bleomycin-induced basal alveolar epithelial cells and C57BL/6 mice. Protein expressions and pathological expressions of EGFR and Ki67 were evaluated to analyze the effect of curcumin via both in vitro and in vivo approaches.

METHODS

The effect of curcumin was investigated both on cell lines (A549) and animal model (both normal and bleomycin-induced mice, n=6) via techniques like western blotting for protein expression. Techniques like immunofluorescence and immunohistochemistry were carried out and examined under confocal microscopy and phase contrast microscopy to analyze the expressions of the said biomarkers. Bleomycin was used as a causative agent to induce inflammation.

RESULTS

The natural polyphenol curcumin could downregulate the expressions levels of Ki67 and EGFR both in vitro and in vivo. Immunofluorescence analysis of proliferative marker Ki67 showed a reduced expression on curcumin treatment in vitro. The pathological sections from treated lungs showed a significant decrease in EGFR and Ki67 levels when exposed to curcumin.

CONCLUSION

We conclude that curcumin, a well-known natural bioactive compound holds strong antiproliferative effects on Ki67 and EGFR expressions.We observed that a clinical outcome in the diagnosis of pulmonary fibrosis remains to be unconvincing so far. Curcumin can be considered as a potential therapeutic.

TRIM32 inhibits the proliferation and migration of pulmonary artery smooth muscle cells through the inactivation of PI3K/Akt pathway in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fetal cardiovascular disease. Tripartite motif 32 (TRIM32) is a member of TRIM family that has been found to be involved in cardiovascular disease. However, the role of TRIM32 in PAH remains unclear. Here we investigated the effects of TRIM32 on hypoxia-induced pulmonary artery smooth muscle cells (PASMCs) in vitro. Our results showed that TRIM32 protein level in the plasma samples from PAH patients was decreased as compared with healthy volunteers. Exposure to hypoxia condition caused a significant decrease in TRIM32 expression in PASMCs. Overexpression of TRIM32 inhibited hypoxia-induced proliferation and migration of PASMCs. TRIM32 overexpression elevated the increased apoptotic rate and caspase-3 activity in hypoxia-induced PASMCs. Moreover, overexpression of TRIM32 reversed hypoxia-induced down-regulation of myocardin, SM 22 and calponin, as well as up-regulation of osteopontin (OPN). Whereas, TRIM32 knockdown shwed the opposite effect. Furthermore, overexpression of TRIM32 inhibited hypoxia-induced activation of PI3K/Akt with decreased phosphorylated level of PI3K and Akt. Additionally, activation of PI3K/Akt by IGF-1 treatment reversed the effects of TRIM32 on hypoxia-induced PASMCs. In conclusion, these findings indicated that TRIM32 was involved in the development of PAH through regulating the proliferation, migration, apoptosis and dedifferentiation of PASMCs, which might be mediated by the PI3K/Akt signaling pathway. Thus, TRIM32 might be a potential target for PAH treatment.

Icotinib Attenuates Monocrotaline-Induced Pulmonary Hypertension by Preventing Pulmonary Arterial Smooth Muscle Cell Dysfunction

BACKGROUND

Aberrant activation of epidermal growth factor receptor (EGFR) signaling pathway is associated with the pathogenesis of pulmonary hypertension (PH). However, the effect of icotinib, a first generation of EGFR tyrosine kinase inhibitor (EGFR-TKI), on PH remains to be elucidated.

METHODS

PH rat model was established by a single intraperitoneal injection of monocrotaline (MCT, 60 mg/kg). Icotinib (15, 30, and 60 mg/kg/day) was administered by oral gavage from the day of MCT injection. After 4 weeks, hemodynamic parameters and histological changes of the pulmonary arterial vessels were assessed, and the phenotypic switching of pulmonary arterial smooth muscle cells (PASMCs) was determined in vivo. Moreover, the effects of icotinib (10 µM) on epidermal growth factor (EGF, 50 ng/ml)-stimulated proliferation, migration, and phenotypic switching of human PASMCs were explored in vitro.

RESULTS

Icotinib significantly reduced the right ventricular systolic pressure and right ventricle hypertrophy index in rats with MCT-induced PH. Moreover, icotinib improved MCT-induced pulmonary vascular remodeling. The expression of contractile marker (smooth muscle 22 alpha (SM22α)) and synthetic markers (osteopontin (OPN) and vimentin) in pulmonary artery was restored by icotinib treatment. In vitro, icotinib suppressed EGF-induced PASMCs proliferation and migration. Meanwhile, icotinib inhibited EGF-induced downregulation of α-smooth muscle actin and SM22α and upregulation of OPN and Collagen I in PASMCs, suggesting that icotinib could inhibit EGF-induced phenotypic switching of PASMCs. Mechanistically, these effects of icotinib were associated with the inhibition of EGFR-Akt/ERK signaling pathway.

CONCLUSIONS

Icotinib can attenuate MCT-induced pulmonary vascular remodeling and improve PH. This effect of icotinib might be attributed to preventing PASMC dysfunction by inhibiting EGFR-Akt/ERK signaling pathway.

Pathobiology of pulmonary artery hypertension: role of long non-coding RNAs

Pulmonary arterial hypertension (PAH) is a disease with complex pathobiology, significant morbidity and mortality, and remains without a cure. It is characterized by vascular remodelling associated with uncontrolled proliferation of pulmonary artery smooth muscle cells, endothelial cell proliferation and dysfunction, and endothelial-to-mesenchymal transition, leading to narrowing of the vascular lumen, increased vascular resistance and pulmonary arterial pressure, which inevitably results in right heart failure and death. There are multiple molecules and signalling pathways that are involved in the vascular remodelling, including non-coding RNAs, i.e. microRNAs and long non-coding RNAs (lncRNAs). It is only in recent years that the role of lncRNAs in the pathobiology of pulmonary vascular remodelling and right ventricular dysfunction is being vigorously investigated. In this review, we have summarized the current state of knowledge about the role of lncRNAs as key drivers and gatekeepers in regulating major cellular and molecular trafficking involved in the pathogenesis of PAH. In addition, we have discussed the limitations and challenges in translating lncRNA research in vivo and in therapeutic applications of lncRNAs in PAH.

Kinases as potential targets for treatment of pulmonary hypertension and right ventricular dysfunction

Pulmonary hypertension (PH) is a progressive pulmonary vasculopathy that causes chronic right ventricular pressure overload and often leads to right ventricular failure. Various kinase inhibitors have been studied in the setting of PH and either improved or worsened the disease, highlighting the importance of understanding the specific role of the respective kinases in a spatiotemporal cellular context. In this review, we will summarize the knowledge on the role of kinases in PH and focus on druggable targets for which certain criteria are met: (a) deregulation of the kinase in PH; (b) small-molecule inhibitors are available (e.g. from the oncology field); (c) preclinical studies have shown their efficacy in PH models; and (d) when available, therapeutic exploitation in human PH has been initiated. Along this line, clinical considerations such as personalized medicine approaches to predict therapy response and adverse side events such as cardiotoxicity together with their clinical management are discussed. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

Augmented Pulmonary Vasoconstrictor Reactivity after Chronic Hypoxia Requires Src Kinase and Epidermal Growth Factor Receptor Signaling

Chronic hypoxia augments pressure- and agonist-induced pulmonary vasoconstriction through myofilament calcium sensitization. NADPH oxidases contribute to the development of pulmonary hypertension, and both epidermal growth factor receptor and Src kinases can regulate NADPH oxidase. We tested the hypothesis that Src-epidermal growth factor receptor (EGFR) signaling mediates enhanced vasoconstrictor sensitivity after chronic hypoxia through NADPH oxidase-derived superoxide generation. Protocols employed pharmacological inhibitors in isolated, pressurized rat pulmonary arteries to examine the contribution of a variety of signaling moieties to enhanced vascular tone after chronic hypoxia. Superoxide generation in pulmonary arterial smooth muscle cells was assessed using the fluorescent indicator dihydroethidium. Indices of pulmonary hypertension were measured in rats treated with the EGFR inhibitor gefitinib. Inhibition of NADPH oxidase, Rac1 (Ras-related C3 botulinum toxin substrate 1), and EGFR abolished pressure-induced pulmonary arterial tone and endothelin-1 (ET-1)-dependent calcium sensitization and vasoconstriction after chronic hypoxia. Consistently, chronic hypoxia augmented ET-1-induced superoxide production through EGFR signaling, and rats treated chronically with gefitinib displayed reduced right ventricular pressure and diminished arterial remodeling. Src kinases were also activated by ET-1 after chronic hypoxia and contributed to enhanced basal arterial tone and vasoconstriction in response to ET-1. A role for matrix metalloproteinase 2 to mediate Src-dependent EGFR activation is further supported by our findings. Our studies support a novel role for an Src kinase-EGFR-NADPH oxidase signaling axis to mediate enhanced pulmonary vascular smooth muscle Ca2+ sensitization, vasoconstriction, and pulmonary hypertension after chronic hypoxia.