Plumbagin promotes human hepatoma SMMC-7721 cell apoptosis via caspase-3/vimentin signal-mediated EMT

Plumbagin ameliorates LPS-induced acute lung injury by regulating PI3K/AKT/mTOR and Keap1-Nrf2/HO-1 signalling pathways

Acute lung injury (ALI) is a major pathophysiological problem characterized by severe inflammation, resulting in high morbidity and mortality. Plumbagin (PL), a major bioactive constituent extracted from the traditional Chinese herb Plumbago zeylanica, has been shown to possess anti-inflammatory and antioxidant pharmacological activities. However, its protective effect on ALI has not been extensively studied. The objective of this study was to investigate the protective effect of PL against ALI induced by LPS and to elucidate its possible mechanisms both in vivo and in vitro. PL treatment significantly inhibited pathological injury, MPO activity, and the wet/dry ratio in lung tissues, and decreased the levels of inflammatory cells and inflammatory cytokines TNF-α, IL-1β, IL-6 in BALF induced by LPS. In addition, PL inhibited the activation of the PI3K/AKT/mTOR signalling pathway, increased the activity of antioxidant enzymes CAT, SOD, GSH and activated the Keap1/Nrf2/HO-1 signalling pathway during ALI induced by LPS. To further assess the association between the inhibitory effects of PL on ALI and the PI3K/AKT/mTOR and Keap1/Nrf2/HO-1 signalling, we pretreated RAW264.7 cells with 740Y-P and ML385. The results showed that the activation of PI3K/AKT/mTOR signalling reversed the protective effect of PL on inflammatory response induced by LPS. Moreover, the inhibitory effects of PL on the production of inflammatory cytokines induced by LPS also inhibited by downregulating Keap1/Nrf2/HO-1 signalling. In conclusion, the results indicate that the PL ameliorate LPS-induced ALI by regulating the PI3K/AKT/mTOR and Keap1-Nrf2/HO-1 signalling, which may provide a novel therapeutic perspective for PL in inhibiting ALI.

Plumbagin Regulates Snail to Inhibit Hepatocellular Carcinoma Epithelial-Mesenchymal Transition in vivo and in vitro

Background/Aims

Plumbagin (PL) has been shown to effe ctively inhibit autophagy, suppressing invasion and migration of hepatocellular carcinoma (HCC) cells. However, the specific mechanism remains unclear. This study aimed to investigate the effect of PL on tumor growth factor (TGF)-β-induced epithelial-mesenchymal transition (EMT) in HCC.

Methods

Huh-7 cells were cultured, and in vivo models of EMT and HCC-associated lung metastasis were developed through tail vein and in situ injections of tumor cells. In vivo imaging and hematoxylin and eosin staining were used to evaluate HCC modeling and lung metastasis. After PL intervention, the expression levels of Snail, vimentin, E-cadherin, and N-cadherin in the liver were evaluated through immunohistochemistry and Western blot. An in vitro TGF-β-induced cell EMT model was used to detect Snail, vimentin, E-cadherin, and N-cadherin mRNA levels through a polymerase chain reaction. Their protein levels were detected by immunofluorescence staining and Western blot.

Results

In vivo experiments demonstrated that PL significantly reduced the expression of Snail, vimentin, and N-cadherin, while increasing the expression of E-cadherin at the protein levels, effectively inhibiting HCC and lung metastasis. In vitro experiments confirmed that PL up-regulated epithelial cell markers, down-regulated mesenchymal cell markers, and inhibited EMT levels in HCC cells.

Conclusion

PL inhibits Snail expression, up-regulates E-cadherin expression, and down-regulates N-cadherin and vimentin expression, preventing EMT in HCC cells and reducing lung metastasis.

Plectin Deficiency in Fibroblasts Deranges Intermediate Filament and Organelle Morphology, Migration, and Adhesion

Plectin, a highly versatile and multifunctional cytolinker, has been implicated in several multisystemic disorders. Most sequence variations in the human plectin gene (PLEC) cause epidermolysis bullosa simplex with muscular dystrophy (EBS-MD), an autosomal recessive skin-blistering disorder associated with progressive muscle weakness. In this study, we performed a comprehensive cell biological analysis of dermal fibroblasts from three different patients with EBS-MD, where PLEC expression analyses revealed preserved mRNA levels in all cases, whereas full-length plectin protein content was significantly reduced or completely absent. Downstream effects of pathogenic PLEC sequence alterations included massive bundling of vimentin intermediate filament networks, including the occurrence of ring-like nuclei-encasing filament bundles, elongated mitochondrial networks, and abnormal nuclear morphologies. We found that essential fibroblast functions such as wound healing, migration, or orientation upon cyclic stretch were significantly impaired in the cells of patients with EBS-MD. Finally, EBS-MD fibroblasts displayed reduced adhesion capacities, which could be attributed to smaller focal adhesion contacts. Our study not only emphasizes plectin's functional role in human skin fibroblasts, it also provides further insights into the understanding of EBS-MD-associated disease mechanisms.

Harnessing function of EMT in hepatocellular carcinoma: From biological view to nanotechnological standpoint

Management of cancer metastasis has been associated with remarkable reduction in progression of cancer cells and improving survival rate of patients. Since 90% of mortality are due to cancer metastasis, its suppression can improve ability in cancer fighting. The EMT has been an underlying cause in increasing cancer migration and it is followed by mesenchymal transformation of epithelial cells. HCC is the predominant kind of liver tumor threatening life of many people around the world with poor prognosis. Increasing patient prognosis can be obtained via inhibiting tumor metastasis. HCC metastasis modulation by EMT and HCC therapy by nanoparticles are discussed here. First of all, EMT happens during progression and advanced stages of HCC and therefore, its inhibition can reduce tumor malignancy. Moreover, anti-cancer compounds including all-trans retinoic acid and plumbaging, among others, have been considered as inhibitors of EMT. The EMT association with chemoresistance has been evaluated. Moreover, ZEB1/2, TGF-β, Snail and Twist are EMT modulators in HCC and enhancing cancer invasion. Therefore, EMT mechanism and related molecular mechanisms in HCC are evaluated. The treatment of HCC has not been only emphasized on targeting molecular pathways with pharmacological compounds and since drugs have low bioavailability, their targeted delivery by nanoparticles promotes HCC elimination. Moreover, nanoparticle-mediated phototherapy impairs tumorigenesis in HCC by triggering cell death. Metastasis of HCC and even EMT mechanism can be suppressed by cargo-loaded nanoparticles.

Plumbagin Exhibits Genotoxicity and Induces G2/M Cell Cycle Arrest via ROS-Mediated Oxidative Stress and Activation of ATM-p53 Signaling Pathway in Hepatocellular Cells

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone, PLB), a naturally occurring naphthoquinone mainly isolated from the plant Plumbago zeylanica L., has been proven to possess anticancer activities towards multiple types of cancer. Although there has been an increasing amount of research regarding its anticancer effects, the association between oxidative stress, genotoxicity and the cell cycle arrest induced by PLB still remains unclear. Therefore, it is important to investigate their potential connections and the involvement of DNA damage and the ataxia telangiectasia mutated protein (ATM)-p53 signaling pathway in PLB’s anticancer mechanism. The present study showed that PLB exposure significantly reduced HCC cell viability and colony formation. In addition, PLB-induced G2/M cell cycle arrest, oxidative stress, and DNA damage was detected, which could be almost blocked by NAC pretreatment. PLB could trigger a DNA damage response by activating cell cycle checkpoints such as ATM, checkpoint kinase 1 (Chk1), checkpoint kinase 2 (Chk2) and p53. Meanwhile, the key modulator of the G2/M transition factor, Cell Division Cycle 25C (cdc25C), was significantly downregulated in an ROS-dependent manner. Furthermore, pretreatment with ATM and p53 inhibitors (KU55933 and Pifithrin-α) could reduce the occurrence of G2/M cell cycle arrest by inhibiting the activation of the ATM-p53 pathway. Taken together, these results indicate that ROS-mediated oxidative stress plays a key role in PLB-induced G2/M cell cycle arrest mediated by the ATM-p53 pathway.

Prognostic Lnc-S100B-2 Affects Cell Apoptosis and Microenvironment of Colorectal Cancer through MLLT10 Signaling

Long noncoding RNA (LncRNA) is closely associated with the development of colorectal cancer (CRC). The chip data and clinical information of GSE104364 and GSE151021 were downloaded by GEOquery. Limma and Kaplan–Meier analysis were performed. Lnc-S100B-2 was obtained, and high expression of Lnc-S100B-2 was predicted to be associated with a lower survival rate. Online software was adopted to predict downstream regulatory genes, and miR-331-3p and Mixed Lineage Leukemia Translocated to 10 (MLLT10) were screened and verified. After silencing Lnc-S100B-2 and MLLT10, the proliferative activity of CRC cells decreased, and the apoptosis rate increased. At the gene and protein levels, the expressions of PCNA, Ki67, and Bcl-2 were decreased in the sh-Lnc-S100B-2 group, sh-MLLT10 group, and sh-Lnc-S100B-2 + sh-MLLT10 group, while the expressions of cleaved caspase 3, caspase 9, and Bax were increased. In vivo, the volume and mass of the tumor decreased in the sh-Lnc-S100B-2 + sh-MLLT10 group. Proliferation and apoptosis-related index (PCNA, Ki67, cleaved caspase 3, caspase 9, Bax, and Bcl-2) expression level was also altered. Meanwhile, the infiltration of immune cells (CD3 (-), CD16 (+), and CD11b (+) cells) decreased. The expressions of epithelial-mesenchymal transformation (EMT) related indicators (E-cadherin, N-cadherin, Vimentin, β-catenin, Snail, and Slug) were changed. E-cadherin and β-catenin were increased in the sh-Lnc-S100B-2 + sh-MLLT10 group, while N-cadherin, vimentin, snail, and slug were decreased. In conclusion, our study found that the expression of Lnc-S100B-2 was dysregulated in CRC. Lnc-S100B-2 could affect cell apoptosis and the microenvironment of CRC through regulating MLLT10.

Vimentin affects colorectal cancer proliferation, invasion, and migration via regulated by activator protein 1

Uncontrolled recurrence and metastasis are important reasons for the high mortality rate of malignant tumors. Vimentin is positively correlated with the degree of malignancy of cancer cells. Vimentin is also highly expressed in colorectal cancer (CRC) cells and plays a critical role in the metastasis and prognosis of CRC. However, the molecular mechanism of vimentin in the progression of CRC is incompletely understood. Therefore, the most active regions (nucleotides: 785-1085 nt) of the vimentin promoter in CRC were identified using luciferase experiments. By transcription factor sequence search and mutation analysis, the activator protein 1 (AP-1) binding site in the region of 785-1085 nt was confirmed. The vimentin promoter activity was enhanced by overexpression of AP-1. The electrophoretic mobility shift assay and chromatin immunoprecipitation assay showed that the binding site was recognized by AP-1. By cell proliferation assay, colony-forming assay, scratch-wound assay, cell migration assay, and cell invasion assay, we demonstrated that the AP-1 overexpression increased CRC cell proliferation, migration, and invasion. However, when vimentin was knocked down by vimentin small hairpin RNA in the CRC cell of AP-1 overexpression, this trend disappeared. Animal experiments and immunohistochemistry showed that AP-1 promoted tumor growth by regulating the vimentin gene. In summary, AP-1 affected metastasis, invasion of CRC cells in vitro, and tumor growth in vivo by activating the vimentin promoter. This study might provide new insights into the molecular mechanisms of the development of CRC and provide potential therapeutic targets for CRC.

Computational and In Vitro Analysis of Plumbagin's Molecular Mechanism for the Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignant tumor and the second leading cause of cancer-related death in the world. Plumbagin (PL) is a small molecule naphthoquinone compound isolated from Plumbago zeylanica L. that has important anticancer properties, but its mechanism requires further investigation. In this study, we used a comprehensive network pharmacology approach to study the mechanism of action of PL for the treatment of HCC. The method includes the construction of multiple networks; moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to identify biological processes and signaling pathways. Subsequently, in vitro experiments were performed to verify the predicted molecular mechanisms obtained from the network pharmacology-based analysis. Network pharmacological analysis showed that PL may exert anti-HCC effects by enhancing reactive oxygen species (ROS) production to generate oxidative stress and by regulating the PI3K/Akt and MAPK signaling pathways. In vitro experiments confirmed that PL mainly mediates the production of ROS, regulates the PI3K/Akt and MAPK signaling pathways to promote apoptosis and autophagy, and shows significant therapeutic effects on HCC. In conclusion, our work proposes a comprehensive systems pharmacology approach to explore the potential mechanism of PL for the treatment of HCC.

Inhibition of Bone Morphogenetic Protein 2 Suppresses the Stemness Maintenance of Cancer Stem Cells in Hepatocellular Carcinoma via the MAPK/ERK Pathway

Background

Hepatocellular carcinoma (HCC) remains a life-threatening malignant tumor. Cancer stem cells (CSCs) harbor tumor-initiating capacity and can be used as a therapeutic target for human malignancies. Bone morphogenetic proteins (BMPs) play a regulatory role in CSCs. This study investigated the role and mechanism of BMP2 in CSCs in HCC.

Methods

BMP2 expression in HCC tissues and cells, and CSCs from HepG2 cells and SMMC7721 cells (HepG2-CSCs and SMMC7721-CSCs) was measured. The association between BMP2 expression and prognosis of HCC patients was analyzed. CSCs were interfered with BMP2 to evaluate the abilities of colony and tumor sphere formation, levels of stemness-related markers, epithelial-mesenchymal transition (EMT), and invasion and migration. Levels of MAPK/ERK pathway-related proteins in HepG2-CSCs were detected after BMP2 knockdown. The effect of the activated MAPK/ERK pathway on HepG2-CSCs was assessed. Finally, the effect of BMP2 inhibition on CSCs in HCC was verified in vivo.

Results

BMP2 showed obvious upregulation in HCC tissues and cells and was further upregulated in CSCs in HCC, with its higher expression indicative of worse prognosis. Silencing BMP2 inhibited colony and tumor sphere formation, levels of stemness-related markers, as well as EMT, invasion and migration of HepG2-CSCs and SMMC7721-CSCs. The MAPK/ERK pathway was suppressed after BMP2 knockdown, and its activation reversed the inhibitory effect of shBMP2 on hepatic CSCs. BMP2 accelerated tumor growth and EMT of CSCs in HCC in vivo.

Conclusion

We concluded that BMP2 knockdown inhibited the EMT, proliferation and invasion of CSCs in HCC, thereby hindering the stemness maintenance via suppressing the MAPK/ERK pathway.

Anticancer Effects and Mechanisms of Action of Plumbagin: Review of Research Advances

Plumbagin (PLB), a natural naphthoquinone constituent isolated from the roots of the medicinal plant Plumbago zeylanica L., exhibited anticancer activity against a variety of cancer cell lines including breast cancer, hepatoma, leukemia, melanoma, prostate cancer, brain tumor, tongue squamous cell carcinoma, esophageal cancer, oral squamous cell carcinoma, lung cancer, kidney adenocarcinoma, cholangiocarcinoma, gastric cancer, lymphocyte carcinoma, osteosarcoma, and canine cancer. PLB played anticancer activity via many molecular mechanisms, such as targeting apoptosis, autophagy pathway, cell cycle arrest, antiangiogenesis pathway, anti-invasion, and antimetastasis pathway. Among these signaling pathways, the key regulatory genes regulated by PLB were NF-kβ, STAT3, and AKT. PLB also acted as a potent inducer of reactive oxygen species (ROS), suppressor of cellular glutathione, and novel proteasome inhibitor, causing DNA double-strand break by oxidative DNA base damage. This review comprehensively summarizes the anticancer activity and mechanism of PLB.

The vimentin cytoskeleton: when polymer physics meets cell biology

The proper functions of tissues depend on the ability of cells to withstand stress and maintain shape. Central to this process is the cytoskeleton, comprised of three polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). IF proteins are among the most abundant cytoskeletal proteins in cells; yet they remain some of the least understood. Their structure and function deviate from those of their cytoskeletal partners, F-actin and microtubules. IF networks show a unique combination of extensibility, flexibility and toughness that confers mechanical resilience to the cell. Vimentin is an IF protein expressed in mesenchymal cells. This review highlights exciting new results on the physical biology of vimentin intermediate filaments and their role in allowing whole cells and tissues to cope with stress.

Suppressive effects of plumbagin on the growth of human bladder cancer cells via PI3K/AKT/mTOR signaling pathways and EMT

Background

Novel chemotherapeutic drugs with good anti-tumor activity are of pressing need for bladder cancer treatment. In this study, plumbagin (PL), a natural plant-derived drug extracted from Chinese herbals, was identified as a promising candidate for human bladder cancer (BCa) chemotherapy.

Methods

The anti-tumor activity of PL was evaluated using a series of in vitro experiments, such as MTT, transwell assay, flow cytometry, quantitative real-time PCR (qRT-PCR) and western blotting. We established xenograft tumors in nude mice by subcutaneous injection with the human bladder cancer T24 cells.

Results

The results showed that PL could inhibit the proliferation, migration and survival of BCa cells (T24 and UMUC3 cells) in a time- and dose-dependent way. We found PL promotes the cell cycle arrest and apoptosis by inhibiting PI3K/AKT/mTOR signaling pathway, which inhibits cell proliferation. In vivo, anti-tumor activity of PL was further investigated using a BCa cell xenograft mice model. To simulate clinical chemotherapy, the PL were intravenously injected with a dose of 10 mg/kg for 10 times. Compared with the blank control, the tumor weight in PL treated group decreased significantly from 0.57 ± 0.04 g to 0.21 ± 0.06 g (P < 0.001).

Conclusions

In our study. We found PL inhibits the proliferation of T24 and UMUC3 cells in vivo and in vitro, which may play a role through several downstream effectors of PI3K/AKT/mTOR signaling pathway to promote the cell cycle arrest and apoptosis. Meanwhile, we consider that PL may inhibit the migration of bladder cancer cells via EMT suppression and induce ROS generation to make cell apoptosis. This work screened out a novel chemotherapeutic drug (plumbagin) with relatively good anti-tumor activity, which possessed great potential in BCa chemotherapy.

Axin1 inhibits proliferation, invasion, migration and EMT of hepatocellular carcinoma by targeting miR-650

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high mortality rate and low survival rate. This study was designed to explore a novel molecular with high sensitivity and specificity, which can be applied in early diagnosis and therapeutic evaluation of HCC. The current study aims to investigate the effect and important role of Axin1 on cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma. qRT-PCR results showed lower Axin1 expression level and higher miR-650 expression level in HCC. Luciferase reporter assay was carried out to verify the negative correlation between Axin1 and miR-650 mRNA levels. CCK-8 assay results showed that the cell proliferation ability was significantly suppressed by Axin1 overexpression in SK-HEP-1 cells. The results in wound healing assay uncovered that cell migration ability was markedly suppressed by Axin1 overexpression. The results in trans-well invasion assay showed that Axin1 overexpression caused decreased invasive ability in SK-HEP-1 cells. The WB results showed that the protein level of E-cad was significantly increased and the protein levels of N-cad, vimentin and snail were obviously reduced following Axin1 overexpression. Whereas, the suppressive effects on cell proliferation, migration, invasion and EMT caused by Axin1 overexpression were abolished by miR-650 mimic. All the results in the current study confirmed the truth that Axin1 overexpression could suppress cell proliferation, migration, invasion and EMT by downregulating miR-650 expression.