Gramine inhibits angiogenesis and induces apoptosis via modulation of TGF-β signalling in 7,12 dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinoma

Effects of Substitution of Wheat Straw by Giant Reed on Growth Performance, Serum Biochemical Parameters, Nutrient Digestibility, and Antioxidant Properties of Sheep

The development and utilization of unconventional forage resources is crucial to alleviating the current situation of shortage of forage resources. Giant reed (Arundo donax) is a promising forage resource from the Poaceae family, one of the largest herbaceous plants globally, with fast growth, high biomass yield, and strong ecological adaptability. However, there are still very few reports on the use of giant reed in livestock and poultry production. The purpose of this study was to evaluate the effects of adding giant reed instead of wheat straw in total mixed ration (TMR) diets on growth performance, blood biochemical indexes, nutrient digestibility, and antioxidant properties of sheep, thereby providing a theoretical basis for the development and utilization of giant reed herbage resources. A total of 24 fattening sheep (Han × Duper) with similar body weight (20 kg), age (2 months), and health status were randomly divided into four groups with six replicates per group. Sheep in the control group were fed a basal diet (CON), and those in the experimental groups were fed giant reed Lvzhou No. 1 instead of wheat straw, with replacement proportions of 10% (GR10), 20% (GR20), and 30% (GR30) of the total diet, respectively. The results showed that (1) the body weight (FBW) and average daily gain (ADG) of sheep in the GR20 and GR30 groups were higher than those of sheep in the CON and GR10 groups (p < 0.05). Meanwhile, the feed to gain ratio (F/G) of sheep in the GR20 and GR30 groups was lower than those sheep in the CON and GR10 groups (p < 0.05), and the F/G of the GR30 group was lower than that of the GR20 group (p < 0.05). (2) The apparent digestibility of DM and CP in groups GR10, GR20 and GR30 was significantly higher than that in group CON (p < 0.005). The digestibility of NDF and ADF in groups GR20, and GR30 was significantly higher than that in the CON and GR10 groups (p < 0.05). (3) dietary substitution of giant reed for wheat straw had no effect on serum biochemical indices, except serum glucose (GLU, p = 0.014) of sheep. In addition, the substitution of giant reed for wheat straw had a tendency to decrease serum urea content of sheep (p = 0.098). (4) Dietary substitution of giant reed for wheat straw significantly improved serum T-SOD (p < 0.001) and T-AOC (p < 0.001), and significantly decreased MDA (p < 0.001) of sheep. In conclusion, replacing wheat straw with giant reed can significantly enhance growth performance, nutrient digestibility, and antioxidant capacity in sheep without adverse effects on their normal physiological functions.

PLGA-Loaded Nedaplatin (PLGA-NDP) Inhibits 7,12-Dimethylbenz[a]anthracene (DMBA) Induced Oral Carcinogenesis via Modulating Notch Signaling Pathway and Induces Apoptosis in Experimental Hamster Model

The present study is designed to evaluate the nanotherapeutic efficacy of prepared PLGA-loaded Nedaplatin (PLGA-NDP) against 7,12-dimethyl benz(a)anthracene (DMBA)-induced experimental oral carcinogenesis in hamster buccal pouch (HBP) model. The buccal pouch of golden Syrian hamsters was painted with 0.5% DMBA in liquid paraffin three times a week for 14 weeks, ultimately leading to the development of oral squamous cell carcinoma (OSCC). Oral administration of PLGA-NDP (preinitiation) and Cisplatin delivery (5 mg/kg b.wt) started 1 week before the carcinogen exposure and continued on alternative days. Post-administration of PLGA-NDP (5 mg/kg b.wt) started 2 days after carcinogen (DMBA) induction until the end of the experiment. After the 14th week, we observed that DMBA-painted hamsters exhibited tumor formation, morphological alterations, and well-differentiated OSSC in addition to the responsive molecular proteins during oral carcinogenesis. Furthermore, immunoblotting analysis demonstrated that PLGA-NDP inhibits Notch signaling, as evidenced by downregulation of Bcl-Xl, Bcl-2, p21, PGE2, HGF, and CXCL12 proteins, and upregulation of p53 and Bax. This apoptotic response is crucial for PLGA-NDP to induce apoptosis. In addition, RT-PCR results showed that PLGA-NDP nanoparticles play a downregulatory role in the therapeutic action of the notch signaling gene (Notch1, Notch 2, Hes1, Hey1, and Jagged1) at the mRNA transcription level in HBP carcinoma. Taken together, these data indicate that PLGA-NDP is a potent inhibitor of oral carcinogenesis and the expansion of cells that specifically target the Notch signaling pathway indicates that obstructing Notch signaling could potentially serve as a new and innovative therapeutic approach for oral squamous cell carcinoma (OSCC).

Gramine improves sepsis-induced myocardial dysfunction by binding to NF-κB p105 and inhibiting its ubiquitination

BACKGROUND

Sepsis and its associated heart failure are among the leading causes of death. Gramine, a natural indole alkaloid, can be extracted from a wide variety of raw plants, and it exhibits therapeutic potential in pathological cardiac hypertrophy. However, the effect of gramine on inflammatory cardiomyopathy, particularly sepsis-induced myocardial injury, remains an unexplored area.

PURPOSE

To determine the role of gramine in sepsis-induced myocardial dysfunction and explore its underlying mechanism.

STUDY DESIGN AND METHODS

In mice, sepsis was established by intraperitoneally injecting lipopolysaccharide (LPS, 10 mg/kg). Subsequently, the effects of gramine administration (50 or 100 mg/kg) on LPS-triggered cardiac dysfunction in mice were investigated. For in vitro studies, isolated primary cardiomyocytes were used to assess the effect of gramine (25 or 50 µM) on LPS-induced apoptosis and inflammation. Additionally, molecular docking, co-immunoprecipitation and ubiquitination analyzes were conducted to explore the underlying mechanisms.

RESULTS

Gramine visibly ameliorated sepsis-induced cardiac dysfunction, inflammatory response, and mortality in vivo. Moreover, it significantly alleviated LPS-induced apoptotic and inflammatory responses in vitro. Furthermore, target prediction for gramine using the SuperPred website indicated that the nuclear factor NF-κB p105 subunit was one of the molecules ranked in priority order with a high model accuracy and a high probability score. Molecular docking studies demonstrated that gramine effectively docked to the death domain of NF-κB p105. Mechanistic studies revealed that gramine suppressed the processing of NF-κB p105 to p50 by inhibiting NF-κB p105 ubiquitination. Additionally, the protective effect of gramine on cardiac injury was almost abolished by overexpressing NF-κB p105.

CONCLUSION

Gramine is a promising bioactive small molecule for treating sepsis-induced myocardial dysfunction, which acts by docking to NF-κB p105 and inhibiting NF-κB p105 ubiquitination, thus preventing its processing to NF-κB p50. Therefore, gramine holds potential as a clinical drug for treating myocardial depression during sepsis.

Bioactive phytocompounds for oral cancer prevention and treatment: A comprehensive and critical evaluation

The high incidence of oral cancer combined with excessive treatment cost underscores the need for novel oral cancer preventive and therapeutic options. The value of natural agents, including plant secondary metabolites (phytochemicals), in preventing carcinogenesis and representing expansive source of anticancer drugs have been established. While fragmentary research data are available on antioral cancer effects of phytochemicals, a comprehensive and critical evaluation of the potential of these agents for the prevention and intervention of human oral malignancies has not been conducted according to our knowledge. This study presents a complete and critical analysis of current preclinical and clinical results on the prevention and treatment of oral cancer using phytochemicals. Our in-depth analysis highlights anticancer effects of various phytochemicals, such as phenolics, terpenoids, alkaloids, and sulfur-containing compounds, against numerous oral cancer cells and/or in vivo oral cancer models by antiproliferative, proapoptotic, cell cycle-regulatory, antiinvasive, antiangiogenic, and antimetastatic effects. Bioactive phytochemicals exert their antineoplastic effects by modulating various signaling pathways, specifically involving the epidermal growth factor receptor, cytokine receptors, toll-like receptors, and tumor necrosis factor receptor and consequently alter the expression of downstream genes and proteins. Interestingly, phytochemicals demonstrate encouraging effects in clinical trials, such as reduction of oral lesion size, cell growth, pain score, and development of new lesions. While most phytochemicals displayed minimal toxicity, concerns with bioavailability may limit their clinical application. Future directions for research include more in-depth mechanistic in vivo studies, administration of phytochemicals using novel formulations, investigation of phytocompounds as adjuvants to conventional treatment, and randomized clinical trials.

Recent Developments of Gramine: Chemistry and Biological Activity

The natural alkaloid gramine has attracted significant attention in both academic and industrial circles because of its potential and diverse biological activities, including antiviral, antibacterial, antifungal, anti-inflammatory and antitumor activities; application in therapy for Alzheimer's disease; serotonin-receptor-related activity; insecticidal activity; and application as an algicide. In this review, we focus on the research advances that have been made for gramine-based molecules since their discovery, providing key information on their extraction and separation, chemical synthesis and diverse biological activities. Data regarding their mechanisms of action are also presented. This comprehensive and critical review will serve as a guide for developing more drug candidates based on gramine skeletons.

Gramine protects against pressure overload-induced pathological cardiac hypertrophy through Runx1-TGFBR1 signaling

BACKGROUND

Gramine, also named 3-(N,N-dimethylaminomethyl) indole, is a indole alkaloid. It is mainly extracted from various natural raw plants. Despite being the simplest 3-aminomethylindole, Gramine has broad pharmaceutical and therapeutic effects, such as vasodilatation, antioxidation, mitochondrial bioenergetics-related effects, and angiogenesis via modulation of TGFβ signaling. However, there is little information available about Gramine's role in heart disease, especially pathological cardiac hypertrophy.

PURPOSE

To investigate Gramine's effect on pathological cardiac hypertrophy and clarify the mechanisms behind its action.

METHODS

In the in vitro experiment, Gramine (25 μM or 50 μM) was used to investigate its role in Angiotensin II-induced primary neonatal rat cardiomyocytes (NRCMs) hypertrophy. In the in vivo experiment, Gramine (50 mg/kg or 100 mg/kg) was administrated to investigate its role in transverse aortic constriction (TAC) surgery mice. Additionally, we explored the mechanisms underlying these roles through Western blot, Real-time PCR, genome-wide transcriptomic analysis, chromatin immunoprecipitation and molecular docking studies.

RESULTS

The in vitro data demonstrated that Gramine treatment obviously improved primary cardiomyocyte hypertrophy induced by Angiotensin II, but had few effects on the activation of fibroblasts. The in vivo experiments indicated that Gramine significantly mitigated TAC-induced myocardial hypertrophy, interstitial fibrosis and cardiac dysfunction. Mechanistically, RNA sequencing and further bioinformatics analysis demonstrated that transforming growth factor β (TGFβ)-related signaling pathway was enriched significantly and preferentially in Gramine-treated mice as opposed to vehicle-treated mice during pathological cardiac hypertrophy. Moreover, this cardio-protection of Gramine was found to mainly involved in TGFβ receptor 1 (TGFBR1)- TGFβ activated kinase 1 (TAK1)-p38 MAPK signal cascade. Further exploration showed that Gramine restrained the up-regulation of TGFBR1 by binding to Runt-related transcription factor 1 (Runx1), thereby alleviating pathological cardiac hypertrophy.

CONCLUSION

Our findings provided a substantial body of evidence that Gramine possessed a potential druggability in pathological cardiac hypertrophy via suppressing the TGFBR1-TAK1-p38 MAPK signaling axis through interaction with transcription factor Runx1.

Screening and identification of miR-181a-5p in oral squamous cell carcinoma and functional verification in vivo and in vitro

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a common malignant tumor associated with poor prognosis. MicroRNAs (miRNAs) play crucial regulatory roles in the cancer development. However, the role of miRNAs in OSCC development and progression is not well understood.

METHODS

We sought to establish a dynamic Chinese hamster OSCC animal model, construct miRNA differential expression profiles of its occurrence and development, predict its targets, and perform functional analysis and validation in vitro.

RESULTS

Using expression and functional analyses, the key candidate miRNA (miR-181a-5p) was selected for further functional research, and the expression of miR-181a-5p in OSCC tissues and cell lines was detected. Subsequently, transfection technology and a nude mouse tumorigenic model were used to explore potential molecular mechanisms. miR-181a-5p was significantly downregulated in human OSCC specimens and cell lines, and decreased miR-181a-5p expression was observed in multiple stages of the Chinese hamster OSCC animal model. Moreover, upregulated miR-181a-5p significantly inhibited OSCC cell proliferation, colony formation, invasion, and migration; blocked the cell cycle; and promoted apoptosis. BCL2 was identified as a target of miR-181a-5p. BCL2 may interact with apoptosis- (BAX), invasion- and migration- (TIMP1, MMP2, and MMP9), and cell cycle-related genes (KI67, E2F1, CYCLIND1, and CDK6) to further regulate biological behavior. Tumor xenograft analysis indicated that tumor growth was significantly inhibited in the high miR-181a-5p expression group.

CONCLUSION

Our findings indicate that miR-181a-5p can be used as a potential biomarker and provide a novel animal model for mechanistic research on oral cancer.

Identification of RNA-splicing factor Lsm12 as a novel tumor-associated gene and a potent biomarker in Oral Squamous Cell Carcinoma (OSCC)

Background

Oral squamous cell carcinoma (OSCC) is one of the common cancers worldwide. The lack of specific biomarkers and therapeutic targets leads to delayed diagnosis and hence the poor prognosis of OSCC patients. Thus, it is urgent to identify effective biomarkers and therapeutic targets for OSCC.

Methods

We established the golden hamster carcinogenic model of OSCC induced by 7,12-dimethylbenz(a) anthrancene (DMBA) and used mRNA microarrays to detect the differentially expressed genes (DEGs). DEGs were validated in OSCC clinical tissue microarrays using immunohistochemistry method. Whole transcriptome sequencing was performed to obtain an overview of biological functions of Lsm12. PCR assay and sequencing were employed to investigate the alternative splicing of genes regulated by Lsm12. Cell proliferation, colony formation, Transwell migration and invasion assay and in vivo tumor formation assay were performed to investigate the roles of Lsm12 and two transcript variants of USO1 in OSCC cells.

Results

Lsm12 was identified to be significantly up-regulated in the animal model of OSCC tumorigenesis, which was validated in the clinical OSCC samples. In the paired normal tissues, Lsm12 staining was negative (91%, 92/101) or weak, while in OSCC tissues, positive rate is 100% and strong staining spread over the whole tissues in 93 (93/101, 92%) cases. Lsm12 overexpression significantly promoted OSCC cell growth, colony formation, migration and invasion abilities, while Lsm12 knockdown showed the opposite trends on these phenotypes and obviously inhibited the tumor formation in vivo. Furthermore, Lsm12 overexpression caused the inclusion of USO1 exon 15 and Lsm12 knockdown induced exon 15 skipping. Exon 15-retained USO1 significantly promoted the malignant phenotypes of OSCC cells when compared with the exon 15-deleted USO1.

Conclusions

We identified Lsm12, a novel tumorigenesis-related gene, as an important regulator involved in OSCC tumorigenesis. Lsm12 is a novel RNA-splicing related gene and can regulate the alternative splicing of USO1 exon 15 which was associated closely with OSCC carcinogenesis. Our findings thus provide that Lsm12 might be a potent biomarker and potential therapeutic target for OSCC.

Naturally derived indole alkaloids targeting regulated cell death (RCD) for cancer therapy: from molecular mechanisms to potential therapeutic targets

Regulated cell death (RCD) is a critical and active process that is controlled by specific signal transduction pathways and can be regulated by genetic signals or drug interventions. Meanwhile, RCD is closely related to the occurrence and therapy of multiple human cancers. Generally, RCD subroutines are the key signals of tumorigenesis, which are contributed to our better understanding of cancer pathogenesis and therapeutics. Indole alkaloids derived from natural sources are well defined for their outstanding biological and pharmacological properties, like vincristine, vinblastine, staurosporine, indirubin, and 3,3′-diindolylmethane, which are currently used in the clinic or under clinical assessment. Moreover, such compounds play a significant role in discovering novel anticancer agents. Thus, here we systemically summarized recent advances in indole alkaloids as anticancer agents by targeting different RCD subroutines, including the classical apoptosis and autophagic cell death signaling pathways as well as the crucial signaling pathways of other RCD subroutines, such as ferroptosis, mitotic catastrophe, necroptosis, and anoikis, in cancer. Moreover, we further discussed the cross talk between different RCD subroutines mediated by indole alkaloids and the combined strategies of multiple agents (e.g., 3,10-dibromofascaplysin combined with olaparib) to exhibit therapeutic potential against various cancers by regulating RCD subroutines. In short, the information provided in this review on the regulation of cell death by indole alkaloids against different targets is expected to be beneficial for the design of novel molecules with greater targeting and biological properties, thereby facilitating the development of new strategies for cancer therapy.

Reserpine inhibits DNA repair, cell proliferation, invasion and induces apoptosis in oral carcinogenesis via modulation of TGF-β signaling

Reserpine is a natural indole alkaloid isolated from Rauwolfia serpentina and has potent antioxidant, antimicrobial, and anti-mutagenic properties. Accordingly, this study aimed to investigate the effect of reserpine on DNA repair, cell proliferation, invasion and apoptosis in 7,12-dimethylbenz[a]anthracene(DMBA)-induced hamster buccal pouch (HBP) carcinogenesis. Transforming growth factor-β (TGF-β) was found to induce Smad2, 3 and 4 phosphorylation triggering Smad3/Snail mediated DNA repair proteins and Smad2/4 nuclear translocation. In contrast, reserpine inhibits TGF-β dependent Smad2/3/4 phosphorylation, thereby blockage Smad3/Snail activation and Smad2/4 nuclear translocation. Interruption of these oncogenic signaling pathways leads to downregulating ERCC1, XPF, Ku70, DNA-PKcs, PCNA, cyclin D1, HIF-1α, IL-6, Mcl-1 and stimulates Bax, cytochrome C, Apaf-1, caspase-9, caspase-3 and PARP protein expressions. This study provides therapeutic potential of reserpine in inhibiting DNA repair, cell proliferation, and invasion while simultaneously inducing apoptosis via modulation TGF-β signals.

Cardenolide-rich fraction of Pergularia tomentosa as a novel Antiangiogenic agent mainly targeting endothelial cell migration

PURPOSE

Angiogenesis related abnormalities underlie several life-threatening disorders. Despite approved therapies, scientists have yet to develop highly efficient, low cost approaches with minimal side effects.

METHODS

We evaluated the antiangiogenic activity of 50% hydroalcoholic extracts of Pergularia tomentosa L. root and aerial parts along with their EtOAc and water fractions, in vivo and in vitro. Transgenic zebrafish line Tg(fli1:EGFP) was used for in vivo assay and human umbilical vein endothelial cell (HUVEC) migration test along with possibility of tube formation were performed as in vitro tests. Furthermore, microvasculature in chicken chorioallantoic membrane (CAM) was assessed under P. tomentosa treatment. The fractionation of the 50% hydroalcoholic extracts was led to the identification of the best active fraction in this study. The metabolite profiling of the active fraction was also carried out using LC-HRESIMS analysis.

RESULTS

Pergularia tomentosa markedly inhibited intersegmental vessel (ISV) formation at 48 h post-fertilization (hpf) embryos in zebrafish. The water fraction of root hydroalcoholic extract (PtR2), showed strong antiangiogenic effect with minimal adverse viability impacts. Over 80% of embryos showed more than 50% inhibition in their ISV development at 20 and 40 μg/mL. PtR2 at 20 μg/mL substantially reduced human umbilical vein endothelial cell (HUVEC) migration up to 40%, considerable destruction of the formed tubes in the tube formation and microvasculature in CAM assays. Immunocytochemistry showed a marked reduction in vascular endothelial cadherin (VE-cadherin) abundance at cell junctions concurrent with substantial reduction of phospho-Akt (p-Akt) and β-catenin protein expressions. Phytochemical profile of PtR2 showed a rich source of cardenolide structures, including ghalakinoside, calactin and calotropin derivatives.

CONCLUSION

Thus, the P. tomentosa cardenolide-rich fraction (PtR2) may hold a considerable promise for an antiangiogenic impact by impairment of endothelial cell (EC) migration and viability. Graphical abstract.

Comparison between tumors in plants and human beings: Mechanisms of tumor development and therapy with secondary plant metabolites

BACKGROUND

Human tumors are still a major threat to human health and plant tumors negatively affect agricultural yields. Both areas of research are developing largely independent of each other. Treatment of both plant and human tumors remains unsatisfactory and novel therapy options are urgently needed.

HYPOTHESIS

The concept of this paper is to compare cellular and molecular mechanisms of tumor development in plants and human beings and to explore possibilities to develop novel treatment strategies based on bioactive secondary plant metabolites. The interdisciplinary discourse may unravel commonalities and differences in the biology of plant and human tumors as basis for rational drug development.

RESULTS

Plant tumors and galls develop upon infection by bacteria (e.g. Agrobacterium tumefaciens and A. vitis, which harbor oncogenic T-DNA) and by insects (e.g. gall wasps, aphids). Plant tumors are benign, i.e. they usually do not ultimately kill their host, but they can lead to considerable economic damage due to reduced crop yields of cultivated plants. Human tumors develop by biological carcinogenesis (i.e. viruses and other infectious agents), chemical carcinogenesis (anthropogenic and non-anthropogenic environmental toxic xenobiotics) and physical carcinogenesis (radioactivity, UV-radiation). The majority of human tumors are malignant with lethal outcome. Although treatments for both plant and human tumors are available (antibiotics and apathogenic bacterial strains for plant tumors, cytostatic drugs for human tumors), treatment successes are non-satisfactory, because of drug resistance and the severe adverse side effects. In human beings, attacks by microbes are repelled by cellular immunity (i.e. innate and acquired immune systems). Plants instead display chemical defense mechanisms, whereby constitutively expressed phytoanticipin compounds compare to the innate human immune system, the acquired human immune system compares to phytoalexins, which are induced by appropriate biotic or abiotic stressors. Some chemical weapons of this armory of secondary metabolites are also active against plant galls. There is a mutual co-evolution between plant defense and animals/human beings, which was sometimes referred to as animal plant warfare. As a consequence, hepatic phase I-III metabolization and excretion developed in animals and human beings to detoxify harmful phytochemicals. On the other hand, plants invented "pro-drugs" during evolution, which are activated and toxified in animals by this hepatic biotransformation system. Recent efforts focus on phytochemicals that specifically target tumor-related mechanisms and proteins, e.g. angiogenic or metastatic inhibitors, stimulators of the immune system to improve anti-tumor immunity, specific cell death or cancer stem cell inhibitors, inhibitors of DNA damage and epigenomic deregulation, specific inhibitors of driver genes of carcinogenesis (e.g. oncogenes), inhibitors of multidrug resistance (i.e. ABC transporter efflux inhibitors), secondary metabolites against plant tumors.

CONCLUSION

The exploitation of bioactive secondary metabolites to treat plant or human tumors bears a tremendous therapeutic potential. Although there are fundamental differences between human and plant tumors, either isolated phytochemicals and their (semi)synthetic derivatives or chemically defined and standardized plant extracts may offer new therapy options to decrease human tumor incidence and mortality as well as to increase agricultural yields by fighting crown galls.

Microcystin-LR induces angiodysplasia and vascular dysfunction through promoting cell apoptosis by the mitochondrial signaling pathway

The harmful algal blooms are becoming increasingly problematic in the regions that drinking water production depends on surface waters. With a global occurrence, microcystins are toxic peptides produced by multiple cyanobacterial genera in the harmful algal blooms. In this study, we examined the effects of microcystin-LR (MC-LR), a representative toxin of the microcystin family, on vascular development in zebrafish and the apoptosis of human umbilical vein endothelial cells (HUVECs). In zebrafish larvae, MC-LR induced angiodysplasia, damaged vascular structures and reduced lumen size at 0.1 μM and 1 μM, leading to the decrease of the blood flow area in the blood vessels and brain hemorrhage, which showed that MC-LR could dose-dependently inhibit vascular development and cause vascular dysfunction. In MC-LR treated HUVECs, the proportion of early apoptosis and late apoptosis cells increased in a concentration-dependent manner. Different concentrations of MC-LR could also activate caspase 3/9 in HUVECs, increase the level of mitochondrial ROS and reduce mitochondrial membrane potential. Additionally, MC-LR could promote the expression of p53 and inhibit the expression of PCNA. The findings showed that MC-LR could promote apoptosis of HUVECs through the mitochondrial signaling pathway. Combined with these results, MC-LR may promote vascular endothelial cell apoptosis through mitochondrial signaling pathway, leading to angiodysplasia and vascular dysfunction.

miR-26 Induces Apoptosis and Inhibits Autophagy in Non-small Cell Lung Cancer Cells by Suppressing TGF-β1-JNK Signaling Pathway

Non-small cell lung cancer (NSCLC) is one of the causes of cancer mortality worldwide. The role of miR-26 in the development and progression of NSCLC remains largely unknown. In this study we found an abnormal expression of miR-26 in human NSCLC tissues. It was found that miR-26 mimics induced cell apoptosis and promoted caspase-3, 9 activities in human NSCLC cells. The miR-26 inhibitor enhanced the expression of the light chain 3 (LC3) protein and the autophagy related genes in NSCLC cells. Moreover, miR-26 regulated apoptosis and autophagy by inhibiting TGF-β expression in a JNK dependent manner. In addition, miR-26 mimics induced cell apoptosis, was involved in the endoplasmic reticulum stress (ERS) signaling pathway. Down-regulation of the ERS, inhibited apoptosis which was induced by miR-26 mimics in NSCLC cells. In in vivo studies, TUNEL staining revealed that the number of TUNEL positive cells of the tumor tissue in the miR-26 treatment group, were significantly increased in comparison with the control group, while the number of TUNEL positive cells in the tumor tissue were remarkably decreased in the groups treated with miR-26, combined with the TGF-β1 inhibitor or JNK inhibitor. Additionally, the immunoreactivity of TGF-β1 in the cells treated with the miR-26 inhibitor, decreased in comparison to the control group. Our results indicated that miR-26 induced apoptosis and inhibited autophagy in human NSCLC cells through the TGF-β1-JNK signaling pathway, suggesting that miR-26 could be a potential novel target for the treatment of NSCLC.