Metadherin confers chemoresistance of cervical cancer cells by inducing autophagy and activating ERK/NF-κB pathway

USP7 promotes cervical cancer progression by stabilizing MTDH expression through deubiquitination

BACKGROUND

Metadherin (MTDH) and ubiquitin specific protease 7 (USP7) have been identified to involve in the tumorigenesis of cervical cancer (CC). USP7 is one of the deubiquitinating enzymes. Here, this study aimed to explore whether USP7 affected CC progression via interacting with MTDH and regulating its stability via deubiquitination.

METHODS

qRT-PCR and western blotting assays detected the levels of genes and proteins. Functional analysis was conducted using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays, respectively. Proteins between USP7 and MTDH were identified by co-immunoprecipitation assay. A mouse xenograft model was established for in vivo analysis.

RESULTS

MTDH was highly expressed in CC tissues and cells, silencing of MTDH suppressed CC cell proliferation, migration, invasion, angiogenesis, and macrophage M2 polarization. Mechanistically, USP7 directly bound to MTDH, and maintained its stability by removing ubiquitination on MTDH. CC tissues and cells showed high USP7 expression, and USP7 knockdown also inhibited CC cell proliferation, migration, invasion, angiogenesis and macrophage M2 polarization, and these effects mediated by USP7 knockdown were reversed by MTDH overexpression. Moreover, USP7 knockdown impeded CC growth in vivo by regulating MTDH.

CONCLUSION

Collectively, USP7 promoted CC cell proliferation, migration, invasion, angiogenesis, and macrophage M2 polarization in vitro, as well as tumor growth in vivo by regulating MTDH.

Autophagy-driven regulation of cisplatin response in human cancers: Exploring molecular and cell death dynamics

Despite the challenges posed by drug resistance and side effects, chemotherapy remains a pivotal strategy in cancer treatment. A key issue in this context is macroautophagy (commonly known as autophagy), a dysregulated cell death mechanism often observed during chemotherapy. Autophagy plays a cytoprotective role by maintaining cellular homeostasis and recycling organelles, and emerging evidence points to its significant role in promoting cancer progression. Cisplatin, a DNA-intercalating agent known for inducing cell death and cell cycle arrest, often encounters resistance in chemotherapy treatments. Recent studies have shown that autophagy can contribute to cisplatin resistance or insensitivity in tumor cells through various mechanisms. This resistance can be mediated by protective autophagy, which suppresses apoptosis. Additionally, autophagy-related changes in tumor cell metastasis, particularly the induction of Epithelial-Mesenchymal Transition (EMT), can also lead to cisplatin resistance. Nevertheless, pharmacological strategies targeting the regulation of autophagy and apoptosis offer promising avenues to enhance cisplatin sensitivity in cancer therapy. Notably, numerous non-coding RNAs have been identified as regulators of autophagy in the context of cisplatin chemotherapy. Thus, therapeutic targeting of autophagy or its associated pathways holds potential for restoring cisplatin sensitivity, highlighting an important direction for future clinical research.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

Metadherin (AEG-1/MTDH/LYRIC) expression: Significance in malignancy and crucial role in colorectal cancer

Metadherin (AEG-1/MTDH/LYRIC) is a 582-amino acid transmembrane protein, encoded by a gene located at chromosome 8q22, and distributed throughout the cytoplasm, peri-nuclear region, nucleus, and nucleolus as well as the endoplasmic reticulum (ER). It contains several structural and interacting domains through which it interacts with transcription factors such as nuclear factor-κB (NF-κB), promyelocytic leukemia zinc finger (PLZF), staphylococcal nuclease domain containing 1 (SND1) and lung homing domain (LHD). It is regulated by miRNAs and mediates its oncogenic function via activation of cell proliferation, survival, migration and metastasis, as well as, angiogenesis and chemoresistance via phosphatidylinositol-3-kinase/AKT (PI3K/AKT), NF-κB, mitogen-activated protein kinase (MAPK) and Wnt signaling pathways. In this chapter, metadherin is reviewed highlighting its role in mediating growth, metastasis and chemoresistance in colorectal cancer (CRC). Metadherin, as well as its variants, and antibodies are associated with CRC progression, poorer prognosis, decreased survival and advanced clinico-pathology. The potential of AEG-1/MTDH/LYRIC as a diagnostic and prognostic marker as well as a therapeutic target in CRC is explored.

Metadherin-mediated mechanisms in human malignancies

Metadherin (MTDH) has been recognized as a novel protein that is critical for the progression of multiple types of human malignancies. Studies have reported that MTDH enhances the metastatic potential of cancer cells by regulating multiple signaling pathways. miRNAs and various tumor-related proteins have been shown to interact with MTDH, making it a potential therapeutic target as well as a biomarker in human malignancies. MTDH plays a critical role in inflammation, angiogenesis, hypoxia, epithelial-mesenchymal transition and autophagy. In this review, we present the function and mechanisms of MTDH for cancer initiation and progression.

Multifunctional Role of Astrocyte Elevated Gene-1 (AEG-1) in Cancer: Focus on Drug Resistance

Simple Summary

Chemotherapy is a major mode of treatment for cancers. However, cancer cells adapt to survive in stressful conditions and in many cases, they are inherently resistant to chemotherapy. Additionally, after initial response to chemotherapy, the surviving cancer cells acquire new alterations making them chemoresistant. Genes that help adapt the cancer cells to cope with stress often contribute to chemoresistance and one such gene is Astrocyte elevated gene-1 (AEG-1). AEG-1 levels are increased in all cancers studied to date and AEG-1 contributes to the development of highly aggressive, metastatic cancers. In this review, we provide a comprehensive description of the mechanism by which AEG-1 augments tumor development with special focus on its ability to regulate chemoresistance. We also discuss potential ways to inhibit AEG-1 to overcome chemoresistance.

Abstract

Cancer development results from the acquisition of numerous genetic and epigenetic alterations in cancer cells themselves, as well as continuous changes in their microenvironment. The plasticity of cancer cells allows them to continuously adapt to selective pressures brought forth by exogenous environmental stresses, the internal milieu of the tumor and cancer treatment itself. Resistance to treatment, either inherent or acquired after the commencement of treatment, is a major obstacle an oncologist confronts in an endeavor to efficiently manage the disease. Resistance to chemotherapy, chemoresistance, is an important hallmark of aggressive cancers, and driver oncogene-induced signaling pathways and molecular abnormalities create the platform for chemoresistance. The oncogene Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) is overexpressed in a diverse array of cancers, and its overexpression promotes all the hallmarks of cancer, such as proliferation, invasion, metastasis, angiogenesis and chemoresistance. The present review provides a comprehensive description of the molecular mechanism by which AEG-1 promotes tumorigenesis, with a special emphasis on its ability to regulate chemoresistance.

Increased HSF1 Promotes Infiltration and Metastasis in Cervical Cancer via Enhancing MTDH-VEGF-C Expression

Purpose

To explore the molecular mechanism of promoting cervical cancer by HSF1 in vivo and in vitro.

Methods

The expression of HSF1 in 110 paraffin-embedded cervical cancer sections of different grades was examined via immunohistochemistry analyses. Expression of HSF1 downstream targets Metadherin (MTDH), VEGF-C and CD31 were studied using immunohistochemistry analyses. HSF1 transcriptional activity in the MTDH promoter region was detected by EMSA, CHIP and luciferase. Cell proliferation and clonality were detected by MTT and clonal formation assay. Cell migration and invasion ability were investigated by scratch analysis and transwell assay. HSF1-mediated tumorigenesis in vivo was examined in xenograft models.

Results

HSF1 expression of cervical cancer cell line was increased compared to normal human cervical tissues. HSF1 enhanced the expression of MTDH, VEGF-C and CD31. HSF1 can combine with MTDH promoter to promote the expression of MTDH. HSF1 enhanced HeLa cell proliferation and clone formation. Furthermore, HSF1 increased HeLa cells migration and invasion in vitro. In the transplanted tumor model, HSF1 inhibited tumor growth in vivo after interference, and reduced the expression of MTDH, VEGF-C and CD31.

Discussion

HSF1 can promote the proliferation, metastasis and invasion of cervical cancer.

Autophagy signals orchestrate chemoresistance of gynecological cancers

Gynecological cancers are characterized by a high mortality rate when chemoresistance develops. Autophagy collaborates with apoptosis and participates in homeostasis of chemoresistance. Recent findings supported that crosstalk of necrotic, apoptotic and autophagic factors, and chemotherapy-driven hypoxia, oxidative stress and ER stress play critical roles in chemoresistance in gynecological cancers. Meanwhile, current studies have shown that autophagy could be regulated by and cooperate with metabolic regulator, survival factors, stemness factors and specific post-translation modification in chemoresistant tumor cells. Meanwhile, non-coding RNA and autophagy crosstalk also contribute to the chemoresistance. Until now, analysis of individual autophagy factors towards the clinical significance and chemoresistance in gynecological cancer is still lacking. We suggest comprehensive integrated analysis of cellular homeostasis and tumor microenvironment to clarify the role of autophagy and the associated factors in cancer progression and chemoresistance. Panel screening of pan-autophagic factors will pioneer the development of risk models for predicting efficacy of chemotherapy and guidelines for systematic treatment and precision medicine.

BRM270 targets cancer stem cells and augments chemo-sensitivity in cancer

Over the past decade, a number of studies have demonstrated the resistance of cancer cells to conventional drugs and have recognized this as a major challenge in cancer therapy. While attempting to understand the underlying mechanisms of chemoresistance, several studies have suggested that the presence of cancer stem cells (CSCs) in tumors is one of the major pathways contributing toward resistance. Chemoresistance leads to cancer treatment failure and worsens the prognosis of patients. Natural herbal compounds are gaining attention as an alternative treatment strategy for cancer. These compounds may be effective against chemoresistant cells either alone or synergistically alongside conventional drugs, sensitizing cancer cells and enhancing the therapeutic efficacy. BRM270 is a natural compound made from seven herbal plant (Saururus chinensis, Citrus unshiu Markovich, Aloe vera, Arnebia euchroma, Portulaca oleracea, Prunella vulgaris var. lilacina and Scutellaria bacicalensis) extracts used in Asian traditional medicine and has the potential to target CSCs. Several studies have demonstrated the positive effects of BRM270 against chemoresistant cancer and its synergy alongside existing cancer drugs, including paclitaxel and gefitinib. These effects have been observed against various cancer types, including resistant non-small cell lung cancer (NSCLC), glioblastoma, multi-drug resistant osteosarcoma, cervical cancer, pancreatic cancer and hepatocarcinoma. The present review discusses the effects of BRM270 treatment against CSC-associated chemoresistance in common types of cancer.

MTDH promotes metastasis of clear cell renal cell carcinoma by activating SND1-mediated ERK signaling and epithelial-mesenchymal transition

BACKGROUND

Metastasis is the principal cause of renal cell carcinoma-associated mortality. Metadherin (MTDH) was identified as a vital metastasis driver involved in the metastatic progression of various types of tumors, suggesting that MTDH is a prognostic metastatic biomarker and potential therapeutic target. The role and mechanism of MTDH in the metastatic progression of ccRCC have not yet been adequately explored.

RESULTS

MTDH was remarkably elevated in ccRCC tissues, especially in metastatic ccRCC tissues, compared with normal kidney tissues and correlated with advanced clinicopathological features and poor prognosis. MTDH activated ERK signaling and EMT, thus promoting the migration and invasion of ccRCC cells. The interaction between MTDH and SND1 at the protein level was confirmed using immunoprecipitation and immunofluorescence. Based on the analysis of datasets from GEO and TCGA, SND1 was remarkably increased in ccRCC, especially in metastatic ccRCC, and associated with advanced clinicopathological features and poor prognosis. Knockdown of SND1 mainly abolished the migration and invasion of ccRCC cells by blocking MTDH-mediated ERK and EMT signaling activation.

CONCLUSION

These results revealed that MTDH may be a prognostic metastatic biomarker of ccRCC that promotes ccRCC metastasis by activating SND1-mediated the ERK and EMT signaling pathways. MTDH may serve as an anti-tumor therapeutic target that can be applied for the clinical treatment of metastatic ccRCC.

METHODS

MTDH/SND1 mRNA expression in clear cell renal cell carcinoma (ccRCC) was comprehensively estimated by analysis of GEO-ccRCC and TCGA-KIRC datasets with R software and packages. MTDH protein expression was assessed in a total of 111 ccRCC patients from Peking University First Hospital by immunohistochemistry (IHC). In vitro migration and invasion assays were carried out, and an in vivo metastatic mouse model was developed to investigate the biological functions of MTDH in ccRCC cells. Correlation analysis, immunoprecipitation, western blotting and immunofluorescence were applied to explore the molecular mechanisms of MTDH in ccRCC.

Metadherin: A Therapeutic Target in Multiple Cancers

Altered expression of many genes and proteins is essential for cancer development and progression. Recently, the affected expression of metadherin (MTDH), also known as AEG-1 (Astrocyte Elevated Gene 1) and Lyric, has been implicated in various aspects of cancer progression and metastasis. Elevated expression of MTDH/AEG-1 has been reported in many cancers including breast, prostate, liver, and esophageal cancers, whereas its expression is low or absent in non-malignant tissues. These expression studies suggest that MTDH may represent a potential tumor associated antigen. MTDH also regulates multiple signaling pathways including PI3K/Akt, NF-κB, Wnt/β-catenin, and MAPK which cooperate to promote the tumorigenic and metastatic potential of transformed cells. Several microRNA have also been found to be associated with the increased MTDH expression in different cancers. Increased MTDH levels were linked to the tumor chemoresistance making it an attractive novel therapeutic target. In this review, we summarize data on MTDH function in various cancers.

Regulatory mechanisms of miR-145 expression and the importance of its function in cancer metastasis

MicroRNAs are post-transcriptional mediators of gene expression and regulation, which play influential roles in tumorigenesis and cancer metastasis. The expression of tumor suppressor miR-145 is reduced in various cancer cell lines, containing both solid tumors and blood malignancies. However, the responsible mechanisms of its down-regulation are a complicated network. miR-145 is potentially able to inhbit tumor cell metastasis by targeting of multiple oncogenes, including MUC1, FSCN1, Vimentin, Cadherin, Fibronectin, Metadherin, GOLM1, ARF6, SMAD3, MMP11, Snail1, ZEB1/2, HIF-1α and Rock-1. This distinctive role of miR-145 in the regulation of metastasis-related gene expression may introduce miR-145 as an ideal candidate for controlling of cancer metastasis by miRNA replacement therapy. The present review aims to discuss the current understanding of the different aspects of molecular mechanisms of miR-145 regulation as well as its role in r metastasis regulation.

Efficient and tumor-specific knockdown of MTDH gene attenuates paclitaxel resistance of breast cancer cells both in vivo and in vitro

Background

Drug resistance of paclitaxel (TAX), the first-line chemotherapy drug for breast cancer, was reported to develop in 90% of patients with breast cancer, especially metastatic breast cancer. Investigating the mechanism of TAX resistance of breast cancer cells and developing the strategy improving its therapeutic efficiency are crucial to breast cancer cure.

Methods and Results

We here report an elegant nanoparticle (NP)-based technique that realizes efficient breast cancer treatment of TAX. Using lentiviral vector-mediated gene knockdown, we first demonstrated that TAX therapeutic efficiency was closely correlated with metadherin (MTDH) gene expression in breast cancer cell lines. This finding was also supported by efficacy of TAX treatment in breast cancer patients from our clinical studies. Specifically, TAX treatment became more effective when MTDH expression was decreased in MCF-7 cancer cells by the blocking nuclear factor-kappa B (NF-κB) pathway. Based on these findings, we subsequently synthesized a polymeric NP that could co-deliver MTDH-small interfering RNA (MTDH–siRNA) and TAX into the breast cancer tumors in tumor-bearing mice. The NPs were composed of a cationic copolymer, which wrapped TAX in the inside and adsorbed the negatively charged siRNA on their surface with high drug-loading efficiency and good stability.

Conclusions

NP-based co-delivery approach can effectively knock down the MTDH gene both in vitro and in vivo, which dramatically inhibits breast tumor growth, achieving effective TAX chemotherapy treatment without overt side effects. This study provides a potential therapeutic strategy for the treatment of a wide range of solid tumors highly expressing MTDH.

Electronic supplementary material

The online version of this article (10.1186/s13058-018-1042-7) contains supplementary material, which is available to authorized users.

CD200Fc reduces LPS-induced IL-1β activation in human cervical cancer cells by modulating TLR4-NF-κB and NLRP3 inflammasome pathway

Chronic inflammation plays an important role in tumorigenesis of cervical cancer. CD200Fc, a CD200R1 agonist, has been found to have anti-inflammatory effects in autoimmune diseases and neuro-degeneration. However, the anti-inflammatory effect of CD200Fc on cervical cancer has not yet to be completely understood. This study investigated the anti-inflammatory effects and mechanisms of CD200Fc in LPS-induced human SiHa cells and Caski cells. SiHa cells and Caski cells were stimulated with 40 μg/ml LPS under different concentrations of CD200Fc for 90 min or 12 hours. The mRNA and protein levels of pro-IL-1β, cleaved-IL-1β and NLRP3, as well as the protein level of cleaved caspase-1, were significantly increased in LPS-induced SiHa cells and Caski cells. LPS stimulation did not change ASC and pro-caspase-1 expression. CD200Fc down-regulated protein expression of cleaved caspase-1 and mRNA and protein expression of pro-IL-1β, cleaved-IL-1β and NLRP3. In addition, the protein levels of TLR4, p-P65 and p-IκB, as well as the translocation of P65 to nucleus, were significantly increased in LPS-induced SiHa cells and Caski cells. LPS stimulation did not change t-P65 and t-IκB on protein levels, which were components of TLR-NF-κB pathway. CD200Fc down-regulated protein expression of TLR4, p-P65 and p-IκB and inhibited the translocation of P65 to nucleus in LPS-induced SiHa cells and Caski cells. These results indicated that CD200Fc appeared to suppress the inflammatory activity of TLR4-NF-κB and NLRP3 inflammasome pathway in LPS-induced SiHa cells and Caski cells. It provided novel mechanistic insights into the potential therapeutic uses of CD200Fc for cervical cancer.

Metadherin contributes to epithelial-mesenchymal transition and paclitaxel resistance induced by acidic extracellular pH in nasopharyngeal carcinoma

Paclitaxel resistance is a challenge to the treatment of nasopharyngeal carcinoma (NPC). An acidic extracellular pH (pH_e), a hallmark of solid tumors, is demonstrated to decrease the efficacy of chemotherapy. However, the precise function of acidic pH_e in mediating chemotherapy in NPC remains unknown. In the present study, acidic pH_e significantly decreased the cytotoxicity of paclitaxel in NPC cells. In addition, epithelial-mesenchymal transition (EMT)-like changes were observed in NPC cells cultured at acidic pH_e. Metadherin (MTDH), a novel oncogene, is expressed in multiple types of solid tumor, and is associated with several malignant cell characteristics, including malignant cell transformation, proliferation, angiogenesis, chemoresistance, invasion and metastasis. In the present study, MTDH expression was increased in NPC cells that had been cultured at an acidic pH_e. Furthermore, the silencing of MTDH expression reversed EMT molecular marker expression and sensitized NPC cells to paclitaxel. Taken together, the results of the present study provide evidence to support an association between acidic pH_e-induced paclitaxel resistance and MTDH-mediated EMT in NPC cells. Thus, targeting MTDH may provide a novel strategy for overcoming chemoresistance in NPC therapy.

Upregulation of the BDNF/TrKB pathway promotes epithelial-mesenchymal transition, as well as the migration and invasion of cervical cancer

Brain-derived neurotrophic factor (BDNF) has previously been demonstrated to be associated with several types of cancer. In addition, its receptor, tropomyosin related kinase B (TrkB) is involved in tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) is associated with metastasis in cancers. Thus, The aim of the present study was to examine whether BDNF/TrKB expression is linked to a poor survival and the acquisition of the EMT phenotype in cervical cancer. We found that a high positive expression of BDNF/TrKB was associated with poor survival in cervical cancer. Our results revealed that high expression levels of BDNF/TrKB were observed in cervical cancer compared to normal cells. Importantly, we demonstrated that the silencing of TrKB suppressed the activation of EMT via the downregulation of N-cadherin, vimentin, matrix metalloproteinase (MMP)2 and MMP9, and the upregulation of E-cadherin and tissue inhibitor of metalloproteinases (TIMP)2, which resulted in suppressed cell proliferation, migration and invasion. Furthermore, high phosphorylation levels of ERK and Akt were observed in the cervical cancer cells, while these levels were decreased in the cells in which TrKB was knocked down. On the whole, these findings suggest that the BDNF/TrKB pathway is a promising target for the prevention of tumor proliferation, invasion, metastasis and EMT in cervical cancer cells.

Association of MTDH immunohistochemical expression with metastasis and prognosis in female reproduction malignancies: a systematic review and meta-analysis

Various literatures have demonstrated that overexpression of Metadherin (MTDH) is correlated with tumor metastasis and it can predict poor survival outcomes in female reproduction malignancies. In order to enhance the statistical power and reach a recognized conclusion, we conducted a systematic review and meta-analysis to thoroughly investigate the association of MTDH expression with tumor metastasis and survival outcomes following PRISMA guidelines. Odds ratios (ORs) and hazard ratios (HRs) were used to demonstrate the impact of MTDH on tumor metastasis and prognosis respectively. Data were pooled with appropriate effects model on STATA12.0. Our results indicated that high MTDH expression is significantly correlated with higher mortality for breast, ovarian and cervical cancer. High immunohistochemical expression of MTDH is remarkably associated with shorter disease-free survival (DFS) in breast cancer but not in ovarian cancer. The pooled results suggested that high level of MTDH significantly predicted distant metastasis and lymph node metastasis in breast cancer. Strong associations were observed between MTDH expression and lymph node metastasis in ovarian and cervical cancer. In conclusion, MTDH might be a novel biomarker which can effectively reflect metastasis status and prognosis of breast cancer. However, its application in clinical practice needs more prospective studies with large samples.

Multi-OMIC profiling of survival and metabolic signaling networks in cells subjected to photodynamic therapy

Photodynamic therapy (PDT) is an established palliative treatment for perihilar cholangiocarcinoma that is clinically promising. However, tumors tend to regrow after PDT, which may result from the PDT-induced activation of survival pathways in sublethally afflicted tumor cells. In this study, tumor-comprising cells (i.e., vascular endothelial cells, macrophages, perihilar cholangiocarcinoma cells, and EGFR-overexpressing epidermoid cancer cells) were treated with the photosensitizer zinc phthalocyanine that was encapsulated in cationic liposomes (ZPCLs). The post-PDT survival pathways and metabolism were studied following sublethal (LC₅₀) and supralethal (LC₉₀) PDT. Sublethal PDT induced survival signaling in perihilar cholangiocarcinoma (SK-ChA-1) cells via mainly HIF-1-, NF-кB-, AP-1-, and heat shock factor (HSF)-mediated pathways. In contrast, supralethal PDT damage was associated with a dampened survival response. PDT-subjected SK-ChA-1 cells downregulated proteins associated with EGFR signaling, particularly at LC₉₀. PDT also affected various components of glycolysis and the tricarboxylic acid cycle as well as metabolites involved in redox signaling. In conclusion, sublethal PDT activates multiple pathways in tumor-associated cell types that transcriptionally regulate cell survival, proliferation, energy metabolism, detoxification, inflammation/angiogenesis, and metastasis. Accordingly, tumor cells sublethally afflicted by PDT are a major therapeutic culprit. Our multi-omic analysis further unveiled multiple druggable targets for pharmacological co-intervention.

Decreased Level of Klotho Contributes to Drug Resistance in Lung Cancer Cells: Involving in Klotho-Mediated Cell Autophagy

Klotho is originally discovered as an anti-aging gene and recently identified as a tumor suppressor in various human cancers. Drug resistance is a major obstacle to affect the treatment of chemotherapy. In the present study, we explore the role of klotho on drug resistance in human lung cancers and investigate the mechanism of klotho on drug resistance in lung cancer cells. First, we detected a panel of six human lung cancer cell lines, including H460, SK-MES-1, cisplatin (DDP)-resistant A549/DDP, its parental subline A549, docetaxel (DTX)-resistant SPC-A-1/DTX, and SPC-A-1 by western blotting analysis. The results showed that klotho level was significantly decreased in chemotherapeutic drug-resistant lung cancer cells. Next, klotho was overexpressed in drug-resistant cancer cell lines and the results showed that overexpression of klotho significantly inhibited cell proliferation of A549/DDP and SPC-A-1/DTX. Conversely, knockdown of the expression of klotho significantly promoted cell growth of lung cancer cells. Furthermore, overexpression of klotho had synergistic effects with cisplatin to inhibit the proliferation of drug-resistant lung cancer cells in a dose- and time-dependent manner. The molecular mechanism was explored by western blotting analysis and the results revealed that the levels of beclin 1 and LC3-II were obviously increased, suggesting cell autophagy enhanced in drug-resistant cancer cells. Importantly, overexpression of klotho would inhibit cell autophagy in A549/DDP cells. All the results demonstrated that the levels of klotho were significantly decreased, which was accompanied by the increased cell autophagy in drug-resistant lung cancer cells. Overexpression of klotho would inhibit cell autophagy in drug-resistant lung cancers, which may probably contribute to reverse drug resistance in lung cancer cells.

Correlated overexpression of metadherin and SND1 in glioma cells

Glioma is the most common primary brain tumor with poor prognosis. Effective treatment of glioma remains a big challenge due to complex pathogenic mechanisms. Previous studies have shown that metadherin (MTDH) and its interacting protein staphylococcal nuclease domain containing 1 (SND1) are overexpressed in many solid tumors. To elucidate the role of MDTH and SND1 in the pathogenesis of glioma, we examined the expression of MTDH and SND1 in primary glioma tissues and found that both MTDH and SND1 were highly expressed, with similar expression patterns. Co-expression of MTDH and SND1 was associated with advanced glioma grades. In addition, we detected the interaction between MTDH and SND1 in cultured glioma cell lines. MTDH could promote the expression of p65 and SND1 in glioma cells. However, enhanced SND1 expression by MTDH was abolished by the inhibition of p65. In conclusion, we demonstrated high expression levels MTDH and SND1 in primary glioma tissues. MTDH might promote glioma by inducing SND1 expression through the activation of NF-κB pathway. MTDH and SND1 may serve as the indicator of malignancy and prognosis as well as therapeutic targets for patients with glioma.

Metadherin is required for the proliferation, migration, and invasion of esophageal squamous cell carcinoma and its meta-analysis

Metadherin (MTDH) was found to be highly expressed in various squamous cell carcinomas (SCCs); however, meta-analysis evaluating the association of MTDH in SCC has not been performed. The purpose of this study was to explore the biological functions of MTDH in esophageal squamous cell carcinoma (ESCC) and to meta-analyze the association between MTDH and SCC. Immunohistochemistry was performed to examine MTDH expression using an ESCC tissue array consisting of 86 ESCC and 78 paired normal adjacent tissues (NATs). MTDH was significantly overexpressed in ESCC tissues compared with NATs and was significantly associated with lymph node metastasis, differentiation, and prognosis. Knockdown of MTDH using an MTDH-short hairpin RNA plasmid caused cell cycle arrest at the G0/G1 phase and induced apoptosis of EC9706 cells. Knockdown of MTDH suppressed the proliferation, invasion, and migration of ESCC cells. Furthermore, meta-analysis revealed that overexpression of MTDH was significantly associated with the lymph node metastasis, advanced clinical stage, and T classification of tissues in SCC, suggesting that MTDH might be used as a potential therapeutic target in the lymph node metastasis of ESCC.

miR-125b Suppresses Proliferation and Invasion by Targeting MCL1 in Gastric Cancer

Understanding the molecular mechanisms underlying gastric cancer progression contributes to the development of novel targeted therapies. In this study, we found that the expression levels of miR-125b were strongly downregulated in gastric cancer and associated with clinical stage and the presence of lymph node metastases. Additionally, miR-125b could independently predict OS and DFS in gastric cancer. We further found that upregulation of miR-125b inhibited the proliferation and metastasis of gastric cancer cells in vitro and in vivo. miR-125b elicits these responses by directly targeting MCL1 (myeloid cell leukemia 1), which results in a marked reduction in MCL1 expression. Transfection of miR-125b sensitizes gastric cancer cells to 5-FU-induced apoptosis. By understanding the function and molecular mechanisms of miR-125b in gastric cancer, we may learn that miR-125b has the therapeutic potential to suppress gastric cancer progression and increase drug sensitivity to gastric cancer.

Matrine inhibits the invasive properties of human osteosarcoma cells by downregulating the ERK-NF-κB pathway

Matrine has been used in anti-inflammatory and anticancer therapies for a long time. However, the antimetastatic effect and molecular mechanism(s) of matrine on osteosarcoma are still unclear. Therefore, the aim of this study was to assess the effects of matrine and related mechanism(s) on osteosarcoma cells. In the study, we found that matrine inhibited the proliferation of osteosarcoma cells in vivo and in vitro and inhibited tumor cell metastasis in vitro at cytotoxic doses. Matrine also decreased the expression of the matrix metalloproteinases-2 and 9, decreased p50 and p65 nuclear translocation, and decreased the phosphorylated level of I-κ-B (IκB)-β. In addition, matrine reduced the phosphorylated levels of extracellular signal-regulated kinase 1/2 proteins, which regulate the invasion of poorly differentiated cancer cells. Finally, when U2OS cells were grown as xenografts in nude mice, intragastric administration of matrine induced a significant dose-dependent decrease in tumor growth. These results show the anticancer properties of matrine, which include the inhibition of invasion and proliferation of human osteosarcoma cells.

microRNA-22 acts as a metastasis suppressor by targeting metadherin in gastric cancer

microRNA (miR)-22 has been reported to be downregulated in hepatocellular, lung, colorectal, ovarian and breast cancer, acting as a tumor suppressor. The present study investigated the potential effects of miR-22 on gastric cancer invasion and metastasis and the molecular mechanism. miR-22 expression was examined in tumor tissues of in 89 gastric cancer patients by in situ hybridization (ISH) analysis. Additionally, the association between miR-22 levels and clinicopathological parameters was analyzed. A luciferase assay was conducted for target identification. The ability of invasion and metastasis of gastric cancer cells in vitro and in vivo was evaluated by cell migration and invasion assays and in a xenograft model. The results showed that miR-22 was downregulated in the gastric cancer specimens and significantly correlated with the advanced clinical stage and lymph node metastasis. In addition, metadherin (MTDH) was shown to be a direct target of miR-22 and the expression of MTDH was inversely correlated with miR-22 expression in gastric cancer. Ectopic expression of miR-22 suppressed cell invasion and metastasis in vitro and in vivo. The present study suggested that miR-22 may be a valuable prognostic factor in gastric cancer. miR-22 inhibited gastric cancer cell invasion and metastasis by directly targeting MTDH. The novel miR-22/MTDH link confirmed in the present study provided a novel, potential therapeutic target for the treatment of gastric cancer.

Overexpression of metadherin mediates metastasis of osteosarcoma by regulating epithelial-mesenchymal transition

OBJECTIVES

Osteosarcoma (OS) is one of the most common primary malignant bone tumours of childhood and adolescence, and is characterized by high propensity for metastasis (specially to the lung), which is the main cause of death. However, molecular mechanisms underlying metastasis of OS are still poorly understood.

MATERIALS AND METHODS

Metadherin (MTDH) was identified to be significantly upregulated in OS tissues that had metastasized compared to OS without metastasis, using a two-dimensional approach of electrophoresis, coupled with mass spectrometry. To understand the function of MTDH in OS, OS cell lines U2OS and SOSP-M were transfected with retroviral shRNA vector against MTDH.

RESULTS

It was found that metastatic propensity as well as cell proliferation were significantly reduced in both U2OS and SOSP-M. Migration and invasion of U2OS and SOSP-M cells were significantly lower after knock-down of MTDH. In addition, epithelial-mesenchymal transition (EMT) was reduced after knock-down of MTDH. Clinicopathologically, overexpression of MTDH was significantly associated with metastasis and poor survival of patients with OS.

CONCLUSION

Taken together, our results demonstrate that MTDH mediated metastasis of OS through regulating EMT. This could be an ideal therapeutic target against metastasis of OS.

Metadherin in prostate, bladder, and kidney cancer: A systematic review

Metadherin (MTDH) has been identified as an important oncogene in carcinogenesis, tumor progression and metastasis in numerous malignancies, through signal transduction pathways. MTDH is a potential biomarker and therapeutic target in cancers. The present systematic review was performed to search for studies regarding MTDH and prostate, bladder and kidney cancer using several databases and the eligible studies were reviewed. MTDH expression was found to significantly increase in prostate, bladder and kidney cancers, not only in clinical tissue samples, but also in cancer cell lines. Reviewing the clinical and statistical analysis revealed that MTDH may be involved in urologic cancer progression, metastasis and prognosis. MTDH may be an independent or one of the cofactors in urologic cancers for prediction of patient survival, and may be involved in potential anticancer strategies. MTDH may be associated with several signal transduction pathways in urologic cancers, indicating latent targets to develop anticancer therapeutic strategy. Further studies are required to confirm these findings.

Progress of cancer research on astrocyte elevated gene-1/Metadherin (Review)

Tumor development is initiated by an accumulation of numerous genetic and epigenetic alterations that promote tumor initiation, invasion and metastasis. Astrocyte elevated gene-1 [AEG-1; also known as Metadherin (MTDH) and Lysine-rich CEACAM1 co-isolated (LYRIC)] has emerged in recent years as a potentially crucial mediator of tumor malignancy, and a key converging point of a complex network of oncogenic signaling pathways. AEG-1/MTDH has a multifunctional role in tumor development that has been found to be involved in the following signaling cascades: i) The Ha-Ras and PI3K/Akt pathways; ii) the nuclear factor-κB signaling pathway; iii) the ERK/mitogen-activated protein kinase and Wnt/β-catenin pathways; and iv) the Aurora-A kinase signaling pathway. Studies have established that AEG-1/MTDH is crucial in tumor progression, including transformation, the evasion of apoptosis, invasion, angiogenesis and metastasis. In addition, recent clinical studies have convincingly associated AEG-1/MTDH with tumor progression and poor prognosis in a number of cancer types, including hepatocellular, esophageal squamous cell, gallbladder and renal cell carcinomas, breast, non-small cell lung, prostate, gastric and colorectal cancers, and glioma, melanoma, neuroblastoma and osteosarcoma. AEG-1/MTDH may be used as a biomarker to identify subgroups of patients who require more intensive treatments and who are likely to benefit from AEG-1/MTDH-targeted therapies. The therapeutic targeting of AEG-1/MTDH may simultaneously block metastasis, suppress tumor growth and enhance the efficacy of chemotherapeutic treatments.