Antisense oligonucleotide against clusterin regulates human hepatocellular carcinoma invasion through transcriptional regulation of matrix metalloproteinase-2 and E-cadherin

Therapeutic Potential of Clusterin Inhibition in Human Cancer

Clusterin (CLU) protein is involved in various pathophysiological processes including carcinogenesis and tumor progression. In recent years, the role of the secretory isoform has been demonstrated in tumor cells, where it inhibits apoptosis and favors the acquisition of resistance to conventional treatments used to treat cancer. To determine the possible therapeutic potential of inhibiting this protein, numerous studies have been carried out in this field. In this article, we present the existing knowledge to date on the inhibition of this protein in different types of cancer and analyze the importance it could have in the development of new therapies targeted against this disease.

The role and function of CLU in cancer biology and therapy

Clusterin (CLU) is a highly evolutionary conserved glycoprotein with multiple isoform-specific functions and is widely distributed in different species. Accumulated evidence has shown the prominent role of CLU in regulating several essential physiological processes, including programmed cell death, metastasis, invasion, proliferation and cell growth via regulating diverse signaling pathways to mediate cancer progression in various cancers, such as prostate, breast, lung, liver, colon, bladder and pancreatic cancer. Several studies have revealed the potential benefit of inhibiting CLU in CLU inhibition-based targeted cancer therapies in vitro, in vivo or in human, suggesting CLU is a promising therapeutic target. This review discusses the multiple functions and mechanisms of CLU in regulating tumor progression of various cancers and summarizes the inhibitors of CLU used in CLU inhibition-based targeted cancer therapies.

The Ins and Outs of Clusterin: Its Role in Cancer, Eye Diseases and Wound Healing

Clusterin (CLU) is a glycoprotein originally discovered in 1983 in ram testis fluid. Rapidly observed in other tissues, it was initially given various names based on its function in different tissues. In 1992, it was finally named CLU by consensus. Nearly omnipresent in human tissues, CLU is strongly expressed at fluid-tissue interfaces, including in the eye and in particular the cornea. Recent research has identified different forms of CLU, with the most prominent being a 75-80 kDa heterodimeric protein that is secreted. Another truncated version of CLU (55 kDa) is localized to the nucleus and exerts pro-apoptotic activities. CLU has been reported to be involved in various physiological processes such as sperm maturation, lipid transportation, complement inhibition and chaperone activity. CLU was also reported to exert important functions in tissue remodeling, cell-cell adhesion, cell-substratum interaction, cytoprotection, apoptotic cell death, cell proliferation and migration. Hence, this protein is sparking interest in tissue wound healing. Moreover, CLU gene expression is finely regulated by cytokines, growth factors and stress-inducing agents, leading to abnormally elevated levels of CLU in many states of cellular disturbance, including cancer and neurodegenerative conditions. In the eye, CLU expression has been reported as being severely increased in several pathologies, such as age-related macular degeneration and Fuch's corneal dystrophy, while it is depleted in others, such as pathologic keratinization. Nevertheless, the precise role of CLU in the development of ocular pathologies has yet to be deciphered. The question of whether CLU expression is influenced by these disorders or contributes to them remains open. In this article, we review the actual knowledge about CLU at both the protein and gene expression level in wound healing, and explore the possibility that CLU is a key factor in cancer and eye diseases. Understanding the expression and regulation of CLU could lead to the development of novel therapeutics for promoting wound healing.

The clusterin connectome: Emerging players in chondrocyte biology and putative exploratory biomarkers of osteoarthritis

Introduction

Clusterin is amoonlighting protein that hasmany functions. It is amultifunctional Q6 holdase chaperone glycoprotein that is present intracellularly and extracellularly in almost all bodily fluids. Clusterin is involved in lipid transport, cell differentiation, regulation of apoptosis, and clearance of cellular debris, and plays a protective role in ensuring cellular survival. However, the possible involvement of clusterin in arthritic disease remains unclear. Given the significant potential of clusterin as a biomarker of osteoarthritis (OA), a more detailed analysis of its complex network in an inflammatory environment, specifically in the context of OA, is required. Based on the molecular network of clusterin, this study aimed to identify interacting partners that could be developed into biomarker panels for OA.

Methods

The STRING database and Cytoscape were used to map and visualize the clusterin connectome. The Qiagen Ingenuity Pathway Analysis (IPA) software was used to analyze and study clusterinassociated signaling networks in OA. We also analyzed transcription factors known to modulate clusterin expression, which may be altered in OA.

Results

The top hits in the clusterin network were intracellular chaperones, aggregate-forming proteins, apoptosis regulators and complement proteins. Using a text-mining approach in Cytoscape, we identified additional interacting partners, including serum proteins, apolipoproteins, and heat shock proteins.

Discussion

Based on known interactions with proteins, we predicted potential novel components of the clusterin connectome in OA, including selenoprotein R, semaphorins, and meprins, which may be important for designing new prognostic or diagnostic biomarker panels.

Contribution of the Transcription Factors Sp1/Sp3 and AP-1 to Clusterin Gene Expression during Corneal Wound Healing of Tissue-Engineered Human Corneas

In order to reduce the need for donor corneas, understanding of corneal wound healing and development of an entirely tissue-engineered human cornea (hTECs) is of prime importance. In this study, we exploited the hTEC to determine how deep wound healing affects the transcriptional pattern of corneal epithelial cells through microarray analyses. We demonstrated that the gene encoding clusterin (CLU) has its expression dramatically repressed during closure of hTEC wounds. Western blot analyses confirmed a strong reduction in the expression of the clusterin isoforms after corneal damage and suggest that repression of CLU gene expression might be a prerequisite to hTEC wound closure. Transfection with segments from the human CLU gene promoter revealed the presence of three regulatory regions: a basal promoter and two more distal negative regulatory regions. The basal promoter bears DNA binding sites for very potent transcription factors (TFs): Activator Protein-1 (AP-1) and Specificity protein-1 and 3 (Sp1/Sp3). By exploiting electrophoretic mobility shift assays (EMSA), we demonstrated that AP-1 and Sp1/Sp3 have their DNA binding site overlapping with one another in the basal promoter of the CLU gene in hCECs. Interestingly, expression of both these TFs is reduced (at the protein level) during hTEC wound healing, thereby contributing to the extinction of CLU gene expression during that process. The results of this study contribute to a better understanding of the molecular mechanisms accounting for the repression of CLU gene expression during corneal wound healing.

The multiple roles and therapeutic potential of clusterin in non-small-cell lung cancer: a narrative review

Worldwide, lung cancer is the most common form of cancer, with an estimated 2.09 million new cases and 1.76 million of death cause in 2018. It is categorized into two subtypes, small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC). Although platinum-based chemotherapy or molecular targeted drugs is recommended for advanced stages of NSCLC patients, however, resistance to drug and chemotherapy are hindrances for patients to fully beneficial from these treatments. Clusterin (CLU), also known as apolipoprotein J, is a versatile chaperone molecule which produced by a wide array of tissues and found in most biologic fluids. There are studies reported high expression of CLU confers resistance to chemotherapy and radiotherapy in different lung cancer cell lines. By silencing CLU using Custirsen (OGX-011), a second-generation antisense oligonucleotide (ASO) that inhibits CLU production, not only could sensitized cells to chemo- and radiotherapy, also could decreased their metastatic potential. We will review here the extensive literature linking CLU to NSCLC, update the current state of research on CLU for better understanding of this unique protein and the development of more effective anti- CLU treatment.

Secretory Clusterin as a Novel Molecular-targeted Therapy for Inhibiting Hepatocellular Carcinoma Growth

BACKGROUND

Although secretory clusterin (sCLU) plays a crucial role in Hepatocellular Carcinoma (HCC) cells proliferation, Multiple Drug Resistance (MDR), metastasis and so on, its targeted effects and exact mechanism are still unknown. This review summarizes some new progress in sCLU as a molecular-targeted therapy in the treatment of HCC.

METHODS

A systematic review of the published English-language literature about sCLU and HCC has been performed using the PubMed and bibliographic databases. Some valuable studies on sCLU in HCC progression were searched for relevant articles with the keywords: HCC, diagnosis, MDR, as molecular-targeted in treatment, and so on.

RESULTS

The incidence of the positive rate of sCLU was significantly higher in HCC tissues as compared to the surrounding tissues at mRNA or protein level, gradually increasing with tumor-nodemetastasis staging (P<0.05). Also, the abnormal level of sCLU was related to poor differentiation degree, and considered as a useful marker for HCC diagnosis or independent prognosis for patients. Hepatic sCLU could be silenced at mRNA level by specific sCLU-shRNA or by OGX-011 to inhibit cancer cell proliferation with an increase in apoptosis, cell cycle arrest, reversal MDR, alteration of cell migration or invasion behaviors, and a decrease in GSK-3β or AKT phosphorylation in vitro, as well as significant suppression of the xenograft growth by down-regulating β-catenin, p-GSK3β, and cyclinD1 expression in vivo.

CONCLUSION

Abnormal hepatic sCLU expression should not only be a new diagnostic biomarker but also a novel promising target for inhibiting HCC growth.

Clusterin inhibition mediates sensitivity to chemotherapy and radiotherapy in human cancer

Since its discovery in 1983, the protein clusterin (CLU) has been isolated from almost all human tissues and fluids and linked to the development of different physiopathological processes, including carcinogenesis and tumor progression. During the last few years, several studies have shown the cytoprotective role of secretory CLU in tumor cells, inhibiting their apoptosis and enhancing their resistance to conventional treatments including hormone depletion, chemotherapy, and radiotherapy. In an effort to determine the therapeutic potential that the inhibition of this protein could have on the development of new strategies for cancer treatment, numerous studies have been carried out in this field, with results, in most cases, satisfactory but sometimes contradictory. In this document, we summarize for the first time the current knowledge of the effects that CLU inhibition has on sensitizing tumor cells to conventional cancer treatments and discuss its importance in the development of new strategies against cancer.

Silencing of Y-box binding protein-1 by RNA interference inhibits proliferation, invasion, and metastasis, and enhances sensitivity to cisplatin through NF-κB signaling pathway in human neuroblastoma SH-SY5Y cells

Y-box binding protein-1 (YB-1), a member of Y-box protein family binding DNA and RNA, has been proposed as a novel marker in multiple malignant tumors and found to be associated with tumor malignancy. Neuroblastoma is an embryonal tumor arising from neuroblast cells of the autonomic nervous system, which is the most common cancer diagnosed in infants. It has been reported that YB-1 is highly expressing in various human tumors including nasopharynx, thyroid, lung, breast, colon, ovary, and prostate cancers. This study aimed to investigate the functional role of YB-1 in neuroblastoma by silencing YB-1 using RNA interference (shRNA) in neuroblastoma SH-SY5Y cells. We found that silencing of YB-1 decreased the proliferation, migration, and invasion of SH-SY5Y cells. At molecular level, inhibition of YB-1 decreased the expression level of PCNA as well as MMP-2 in neuroblastoma SH-SY5Y cells. Also, we discovered that YB-1 silencing sensitized SH-SY5Y cells to cisplatin and promoted the apoptosis induced by cisplatin due to down-regulation of multidrug resistance (MDR) 1 protein via NF-κB signaling pathway. Therefore, we consider that targeting YB-1 is promising for neuroblastoma treatment and for overcoming its cisplatin resistance in the development of new neuroblastoma therapeutic strategies.

Indole-3- carbinol enhances sorafenib cytotoxicity in hepatocellular carcinoma cells: A mechanistic study

Sorafenib is the only chemotherapeutic agent currently approved for unresectable hepatocellular carcinoma (HCC). However, poor response rates have been widely reported. Indole-3-carbinol (I3C) is a potential chemopreventive phytochemical. The present study aimed to explore the potential chemomodulatory effects of I3C on sorafenib in HCC cells as well as the possible underlying mechanisms. I3C exhibited a greater cytotoxicity in HepG2 cells compared to Huh-7 cells (p < 0.0001). Moreover, the co-treatment of HepG2 cells with I3C and sorafenib was more effective (p = 0.002). Accordingly, subsequent mechanistic studies were carried on HepG2 cells. The results show that the ability of I3C to enhance sorafenib cytotoxicity in HCC cells could be partially attributed to increasing the apoptotic activity and decreasing the angiogenic potentials. The combination had a negative effect on epithelial-mesenchymal transition (EMT). Increased NOX-1 expression was also observed which may indicate the involvement of NOX-1 in I3C chemomodulatory effects. Additionally, the combination induced cell cycle arrest at the G₀/G₁ phase. In conclusion, these findings provide evidence that I3C enhances sorafenib anti-cancer activity in HCC cells.

Heat shock proteins in hepatocellular carcinoma: Molecular mechanism and therapeutic potential

Heat shock proteins (HSPs) are highly conserved proteins, which are expressed at low levels under normal conditions, but significantly induced in response to cellular stresses. As molecular chaperones, HSPs play crucial roles in protein homeostasis, apoptosis, invasion and cellular signaling transduction. The induction of HSPs is an important part of heat shock response, which could help cancer cells to adapt to stress conditions. Because of the constant stress condition in tumor microenvironment, HSPs overexpression is widely reported in many human cancers. In light of the significance of HSPs for cancer cells to survive and obtain invasive phenotype under stress condition, HSPs are often associated with poor prognosis and treatment resistance in many types of human cancers. It has been described that upregulation of HSPs may serve as diagnostic and prognostic markers in hepatocellular carcinoma (HCC). Targeting HSPs with specific inhibitor alone or in combination with chemotherapy regimens holds promise for the improvement of outcomes for HCC patients. In this review, we summarize the expression profiles, functions and molecular mechanisms of HSPs (HSP27, HSP70 and HSP90) as well as a HSP-like protein (clusterin) in HCC. In addition, we address progression and challenges in targeting these HSPs as novel therapeutic strategies in HCC.

Diagnostic and prognostic significance of secretory clusterin expression in patients with hepatocellular carcinoma

The upregulation of secretory clusterin (sCLU) is associated with tumor progression by contributing to angiogenesis, chemo-resistance, cell survival, and metastasis. However, its diagnostic or prognostic values for hepatocellular carcinoma (HCC) still remain to be clarified. The average serum sCLU level analyzed by an enzyme-linked immunosorbent assay was significantly higher (P < 0.001) in HCC patients than that in any of cases with cirrhosis, chronic hepatitis, or healthy control. The area under receiver operating characteristic curve and diagnostic sensitivity were 0.75 and 74.7 % in sCLU, and 0.74 and 58.7 % in α-fetoprotein (AFP), respectively. The combining detections of sCLU and AFP rose up to 90.7 % for HCC diagnosis. In liver, sCLU by immunohistochemistry was significantly higher (P < 0.001) in the HCC (77.3 %) group than that in their para-cancerous group (33.3 %). Abnormal serum or tissue sCLU expression was closely associated with tumor-node-metastasis (TNM) classification of malignant tumors and lymph node metastasis, as an independent prognosis factor (hazard ratio, 2.287; 95 % confidence interval, 1.044-5.007; P = 0.039), and higher sCLU expression significantly correlated (χ (2) = 4.252, P = 0.039) with poor survival of HCC patients analyzed by multivariate Cox regression or Kaplan-Meier method, suggesting that abnormal sCLU expression associated with tumor progression could be a potential diagnostic and prognostic biomarker for HCC.

Inhibition of protein kinase C by isojacareubin suppresses hepatocellular carcinoma metastasis and induces apoptosis in vitro and in vivo

Targeted inhibition of protein kinase C (PKC) inhibits hepatocellular carcinoma (HCC) proliferation and metastasis. We previously reported the cytotoxicity of a series of synthetic phenyl-substituted polyoxygenated xanthone derivatives against human HCC. In the current study, the most potent natural product, isojacareubin (ISJ), was synthesized, and its cellular-level antihepatoma activities were evaluated. ISJ significantly inhibited cell proliferation and was highly selective for HCC cells in comparison to nonmalignant QSG-7701 hepatocytes. Moreover, ISJ exhibited pro-apoptotic effects on HepG2 hepatoma cells, as well as impaired HepG2 cell migration and invasion. Furthermore, ISJ was a potent inhibitor of PKC, with differential actions against various PKC isotypes. ISJ selectively inhibited the expression of aPKC (PKCζ) in the cytosol and the translocation of cytosolic PKCζ to membrane site. ISJ also directly interacted with cPKC (PKCα) and nPKC (PKCδ, PKCε and PKCμ) and thereby inhibited the early response of major MAPK phosphorylation and the late response of HCC cell invasion and proliferation. In a hepatoma xenograft model, ISJ pretreatment resulted in significant antihepatoma activity in vivo. These findings identify ISJ as a promising lead compound for the development of new antihepatoma agents and may guide the search for additional selective PKC inhibitors.

MiR-324-5p Suppresses Hepatocellular Carcinoma Cell Invasion by Counteracting ECM Degradation through Post-Transcriptionally Downregulating ETS1 and SP1

Hepatocellular carcinoma (HCC) is one of the common malignancies, which is highly metastatic and the third common cause of cancer deaths in the world. The invasion and metastasis of cancer cells is a multistep and complex process which is mainly initiated by extracellular matrix (ECM) degradation. Aberrant expression of microRNA has been investigated in HCC and shown to play essential roles during HCC progression. In the present study, we found that microRNA-324-5p (miR-324-5p) was downregulated in both HCC cell lines and tissues. Ectopic miR-324-5p led to the reduction of HCC cells invasive and metastatic capacity, whereas inhibition of miR-324-5p promoted the invasion of HCC cells. Matrix metalloproteinase 2 (MMP2) and MMP9, the major regulators of ECM degradation, were found to be downregulated by ectopic miR-324-5p, while upregulated by miR-324-5p inhibitor. E26 transformation-specific 1 (ETS1) and Specificity protein 1 (SP1), both of which could modulate MMP2 and MMP9 expression and activity, were presented as the direct targets of and downregulated by miR-324-5p. Downregulation of ETS1 and SP1 mediated the inhibitory function of miR-324-5p on HCC migration and invasion. Our study demonstrates that miR-324-5p suppresses hepatocellular carcinoma cell invasion and might provide new clues to invasive HCC therapy.

Silence of MACC1 expression by RNA interference inhibits proliferation, invasion and metastasis, and promotes apoptosis in U251 human malignant glioma cells

The overexpression of metastasis-associated in colon cancer 1 (MACC1) has been demonstrated not only in colon cancer, but also in various other types of cancer. Gliomas are the most common type of intracranial tumors, and recent studies have reported MACC1 to be involved in human glioma progression. The present study aimed to investigate the effects of MACC1 expression silencing in glioma cells using RNA interference, in order to determine the underlying biological mechanisms of glioma progression, including proliferation, apoptosis, invasion and metastasis. The expression levels of MACC1 were determined in various types of U251 glioma cells using western blot analyses. MACC1-specific short hairpin RNA (shRNA) was used to silence the expression of MACC1 in the U251 cells. The results obtained following MACC1 silencing demonstrated a significant inhibition of cell proliferation, invasion and migration, as well as a marked enhancement of apoptosis. MACC1 shRNA-induced inhibition of cell proliferation was observed by colony forming and MTT assays, and cell apoptosis was measured using flow cytometry and Hoechst staining. In addition, inhibition of cell invasion and migration was assessed using wound healing and transwell assays. Western blotting and fluorescence-activated cell sorting (FACS) revealed a G₀/G₁ phase cell cycle arrest regulated by cyclins D1 and E; cell apoptosis regulated by caspase-3; and cell invasion and migration regulated by matrix metalloproteinases 2 and 9, respectively. The present study demonstrated that the expression levels of MACC1 were significantly correlated with the biological processes underlying glioma cell proliferation, invasion and metastasis. Therefore, MACC1 may serve as a promising novel therapeutic target in human glioma. Notably, the inhibition of MACC1 expression by shRNA may prove to be an effective genetic therapeutic strategy for glioma treatment.

Apolipoprotein J, a glucose-upregulated molecular chaperone, stabilizes core and NS5A to promote infectious hepatitis C virus virion production

BACKGROUND & AIMS

Hepatitis C virus (HCV) infection leads to glucose abnormality. HCV depends on lipid droplets (LDs) and very-low density lipoproteins for assembly/releasing; however, the components and locations for this process remain unidentified. Apolipoprotein J (ApoJ), upregulated by glucose, functions as Golgi chaperone of secreted proteins and resides abundantly in very-low density lipoproteins. This study investigates the interplay between glucose, ApoJ and HCV virion production.

METHODS

The effects of high glucose on ApoJ expression and HCV production were evaluated with cultivated HuH7.5, primary human hepatocytes, and in treatment naive chronic hepatitis C patients. How ApoJ affects HCV lifecycle was assessed using siRNA knockdown strategy in JFH1 infected and subgenomic replicon cells. The interactions and locations of ApoJ with viral and host components were examined by immunoprecipitation, immunofluorescence and subcellular fractionation experiments.

RESULTS

HCV infection increased ApoJ expression, which in parallel with HCV infectivity was additionally elevated with high glucose treatment. Serum ApoJ correlated positively with fasting blood glucose concentration and HCV-RNA titre in patients. ApoJ silencing reduced intracellular and extracellular HCV infectivity and extracellular HCV-RNA, but accumulated intracellular HCV-RNA in HCV-infected cells. ApoJ interacted with HCV core and NS5A and stabilized the dual protein complex. HCV infection dispersed cytoplasmic ApoJ from the compact zones of the Golgi to encircle LDs, where co-localization of the core, NS5A, HCV-RNA, subcellular markers for LDs, endoplasmic reticulum (ER), Golgi, and membrane contact sites occurred.

CONCLUSIONS

ApoJ facilitates infectious HCV particle production via stabilization of core/NS5A, which might surround LDs at the ER-Golgi membrane contact site.

Downregulation of CD147 by chitooligosaccharide inhibits MMP-2 expression and suppresses the metastatic potential of human gastric cancer

Metastasis is considered to be the major cause of mortality in patients with cancer, and gastric cancer is a highly metastatic cancer. In the present study, the anti-metastatic activity of chitooligosaccharide (COS) in human gastric cancer cells and its underlying mechanism were investigated. It was found that COS significantly inhibited SGC-7901 cell proliferation and metastasis in a dose-dependent manner, as observed by MTT, wound-healing and Transwell assays. Quantitative real-time polymerase chain reaction and western blot analysis indicated that COS could decrease the expression of cluster of differentiation 147 (CD147) and subsequently reduce matrix metalloproteinase-2 (MMP-2) expression. A clear dose-dependent inhibition of MMP-2 activity was also observed in SGC-7901 cells following treatment with COS in gelatin zymography experiments. Furthermore, overexpression of CD147 (when transfected with pEGFP-C1 plasmid) in SGC-7901 cells partially protected against COS-induced inhibition of MMP-2. The results of the present study demonstrated the potential of COS in suppressing gastric cancer metastasis, and that the CD147/MMP-2 pathway may be involved as the key mechanism of its anti-metastatic effect.

Clusterin: a key player in cancer chemoresistance and its inhibition

Clusterin is a heterodimeric disulfide-linked glycoprotein (449 amino acids) isolated in the rat prostate after castration. It is widely distributed in different tissues and highly conserved in species. There are two isoforms (1 and 2) with antagonistic actions regarding apoptosis. Clusterin is implicated in a number of biological processes, including lipid transport, membrane recycling, cell adhesion, programmed cell death, and complement cascade, representing a truly multifunctional protein. Isoform 2 is overexpressed under cellular stress conditions and protects cells from apoptosis by impeding Bax actions on the mitochondrial membrane and exerts other protumor activities, like phosphatidylinositol 3-kinase/protein kinase B pathway activation, modulation of extracellular signal-regulated kinase 1/2 signaling and matrix metallopeptidase-9 expression, increased angiogenesis, modulation of the nuclear factor kappa B pathway, among others. Its overexpression should be considered as a nonspecific cellular response to a wide variety of tissue insults like cytotoxic chemotherapy, radiation, excess of free oxygen radicals, androgen or estrogen deprivation, etc. A review of the recent literature strongly suggests potential roles for custirsen in particular, and proapoptosis treatments in general, as novel modalities in cancer management. Inhibition of clusterin is known to increase the cytotoxic effects of chemotherapeutic agents, and custirsen, a second-generation antisense oligonucleotide that blocks clusterin, is being tested in a Phase III clinical trial after successful results were achieved in Phase II studies. A major issue in cancer evolution that remains unanswered is whether clusterin represents a driving force of tumorigenesis or a late phenomenon after chemotherapy. This review presents preclinical data that encourages trials in various types of cancer other than advanced castration-resistance prostate cancer and discusses briefly the appropriate timing for clusterin inhibition in the clinical context.

Comparative multidimensional molecular analyses of pediatric diffuse intrinsic pontine glioma reveals distinct molecular subtypes

Diffuse intrinsic pontine glioma (DIPG) is a highly morbid form of pediatric brainstem glioma. Here, we present the first comprehensive protein, mRNA, and methylation profiles of fresh-frozen DIPG specimens (n = 14), normal brain tissue (n = 10), and other pediatric brain tumors (n = 17). Protein profiling identified 2,305 unique proteins indicating distinct DIPG protein expression patterns compared to other pediatric brain tumors. Western blot and immunohistochemistry validated upregulation of Clusterin (CLU), Elongation Factor 2 (EF2), and Talin-1 (TLN1) in DIPGs studied. Comparisons to mRNA expression profiles generated from tumor and adjacent normal brain tissue indicated two DIPG subgroups, characterized by upregulation of Myc (N-Myc) or Hedgehog (Hh) signaling. We validated upregulation of PTCH, a membrane receptor in the Hh signaling pathway, in a subgroup of DIPG specimens. DNA methylation analysis indicated global hypomethylation of DIPG compared to adjacent normal tissue specimens, with differential methylation of 24 genes involved in Hh and Myc pathways, correlating with protein and mRNA expression patterns. Sequencing analysis showed c.83A>T mutations in the H3F3A or HIST1H3B gene in 77 % of our DIPG cohort. Supervised analysis revealed a unique methylation pattern in mutated specimens compared to the wild-type DIPG samples. This study presents the first comprehensive multidimensional protein, mRNA, and methylation profiling of pediatric brain tumor specimens, detecting the presence of two subgroups within our DIPG cohort. This multidimensional analysis of DIPG provides increased analytical power to more fully explore molecular signatures of DIPGs, with implications for evaluating potential molecular subtypes and biomarker discovery for assessing response to therapy.

The effects of shRNA-mediated gene silencing of transcription factor SNAI1 on the biological phenotypes of breast cancer cell line MCF-7

To research the effects of silencing transcription factor SNAI1 on the in vitro biological phenotypes of breast cancer cell line MCF-7, based on the gene sequence of SNAI1, we linked shRNA with the green fluorescent protein-expressing eukaryotic expression vector pGCsilencer™ U6/Neo/GFP, and transfected it into MCF-7 cells. The SNAI1 gene-silencing effect was authenticated by RT-PCR and immunofluorescence. We then examined the effect of gene silencing on the expression of epithelial and mesenchymal markers and on their biological phenotypes of the target cells. Finally, we explained that SNAI1 was bound to E-cadherin in MCF-7 cells by ChIP. Silencing SNAI1 upregulated the expression of epithelial markers claudin-4, claudin-7, and E-cadherin, while expression of the mesenchymal marker matrix metalloproteinase-2 was downregulated. The capacity for proliferation, migration, and invasion was diminished. SNAI1 binds to the E-cadherin gene promoter and inhibits its transcription. We can conclude that silencing gene SNAI1 inhibits expression of properties that are associated with the malignant phenotype of MCF-7 cells and reverses the epithelial-mesenchymal transition process by regulating relevant target gene E-cadherin.