Novel therapeutic targets for pancreatic cancer

The role of collagen triple helix repeat containing 1 (CTHRC1) in cancer development and progression

INTRODUCTION

Collagen triple helix repeat containing 1 (CTHRC1) is a protein that has been implicated in pro-migratory pathways, arterial tissue-repair processes, and inhibition of collagen deposition via the regulation of multiple signaling cascades. Studies have also demonstrated an upregulation of CTHRC1 in multiple cancers where it has been linked to enhanced proliferation, invasion, and metastasis. However, the understanding of the exact role and mechanisms of CTHRC1 in cancer is far from complete.

AREAS COVERED

This review focuses on analyzing the role of CTHRC1 in cancer as well as its associations with clinicopathologies and cancer-related processes and signaling. We have also summarized the available literature information regarding the role of CTHRC1 in tumor microenvironment and immune signaling. Finally, we have discussed the mechanisms associated with CTHRC1 regulations, and opportunities and challenges regarding the development of CTHRC1 as a potential target for cancer management.

EXPERT OPINION

CTHRC1 is a multifaceted protein with critical roles in cancer progression and other pathological conditions. Its association with lower overall survival in various cancers, and impact on the tumor immune microenvironment make it an intriguing target for further research and potential therapeutic interventions in cancer.

Regucalcin Is a Potential Regulator in Human Cancer: Aiming to Expand into Cancer Therapy

Regucalcin, a calcium-binding protein lacking the EF-hand motif, was initially discovered in 1978. Its name is indicative of its function in calcium signaling regulation. The rgn gene encodes for regucalcin and is situated on the X chromosome in both humans and vertebrates. Regucalcin regulates pivotal enzymes involved in signal transduction and has an inhibitory function, which includes protein kinases, protein phosphatases, cysteinyl protease, nitric oxide dynthetase, aminoacyl-transfer ribonucleic acid (tRNA) synthetase, and protein synthesis. This cytoplasmic protein is transported to the nucleus where it regulates deoxyribonucleic acid and RNA synthesis as well as gene expression. Overexpression of regucalcin inhibits proliferation in both normal and cancer cells in vitro, independent of apoptosis. During liver regeneration in vivo, endogenous regucalcin suppresses cell growth when overexpressed. Regucalcin mRNA and protein expressions are significantly downregulated in tumor tissues of patients with various types of cancers. Patients exhibiting upregulated regucalcin in tumor tissue have shown prolonged survival. The decrease of regucalcin expression is linked to the advancement of cancer. Overexpression of regucalcin carries the potential for preventing and treating carcinogenesis. Additionally, extracellular regucalcin has displayed control over various types of human cancer cells. Regucalcin may hold a prominent role as a regulatory factor in cancer development. Supplying the regucalcin gene could prove to be a valuable asset in cancer treatment. The therapeutic value of regucalcin suggests its potential significance in treating cancer patients. This review delves into the most recent research on the regulatory role of regucalcin in human cancer development, providing a novel approach for treatment.

The overexpressed regucalcin represses the growth via regulating diverse pathways linked to EGF signaling in human ovarian cancer SK-OV-3 cells: Involvement of extracellular regucalcin

AIMS

Regucalcin, which plays a multifunctional role in cell regulation, contributes as a suppressor in carcinogenesis. Survival of cancer patients is prolonged with high expression of regucalcin in tumor tissues. Ovarian cancer is the most lethal in gynecologic malignancies. This study elucidates the repressive role of regucalcin on the growth of human ovarian cancer SK-OV-3 cells that are resistant to cytotoxic cancer drugs.

MATERIALS AND METHODS

SK-OV-3 wild type-cells and regucalcin-overexpressing cells (transfectants) were cultured in Dulbecco's Modification of Eagle's Medium containing 10 % fetal bovine serum.

KEY FINDINGS

Colony formation and proliferation of SK-OV-3 cells were repressed by regucalcin overexpression. The suppressive effects of regucalcin on proliferation were independent of cell death. The proliferation of SK-OV-3 wild-type cells was repressed by various inhibitors, including cell cycle, signaling processes, and transcriptional activity. The effects of all inhibitors were not revealed in transfectants, suggesting the involvement of multiple signaling pathways in regucalcin effects. Of note, the overexpressed regucalcin declined the levels of Ras, Akt, mitogen-activating protein kinase, NF-κB p65, β-catenin, and STAT3, while it raised the levels of tumor suppressors p53 and Rb, and cell cycle inhibitor p21. Interestingly, the stimulatory effects of epidermal growth factor (EGF) on cell proliferation were blocked in regucalcin-overexpressing cells. Extracellular regucalcin repressed the proliferation independent of the death of SK-OV-3 cells and blocked EGF-enhanced cell proliferation.

SIGNIFICANCES

The overexpressed regucalcin may repress cell proliferation by targeting diverse signal pathways, including EGF signaling. This study offers a novel approach to the treatment of ovarian cancer with regucalcin.

IGF1 receptor-targeted black TiO2 nanoprobes for MRI-guided synergetic photothermal-chemotherapy in drug resistant pancreatic tumor

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest malignant tumors with features of matrix barrier caused poor drug permeability, and susceptibility to drug resistance. Herein, a PDAC and its stromal cell dual-targeted photothermal-chemotherapy strategy is explored to loosen the matrix and reverse drug resistance. To achieve this goal, black TiO2-Gd nanocomposites were conjugated with insulin like growth factor 1 (IGF1), and loaded with gemcitabine (GEM) to construct bTiO2-Gd-IGF1-GEM nanoprobes. In vitro results show that under 808 nm near-infrared irradiation, killing effect of the nanoprobes on drug-resistant MIA PaCa-2 cell is 3.3 times than that of GEM alone. In vivo experiments indicate the synergetic photothermal-chemotherapy not only loosens fibrous matrix of pancreatic tumor model, but also dramatically inhibits tumor growth, and almost completely eradicates the tumor after 12 days of treatment. In addition, relaxation rate of the nanoprobes is 8.2 times than commercial contrast agent Magnevist, therefore boosts the signal of magnetic resonance imaging in pancreatic tumor. In conclusion, our results reinforce that the prepared nanoprobes are promising to break matrix barrier and overcome drug resistance in PDAC.

Inhibitors of the Cancer Target Ribonucleotide Reductase, Past and Present

Ribonucleotide reductase (RR) is an essential multi-subunit enzyme found in all living organisms; it catalyzes the rate-limiting step in dNTP synthesis, namely, the conversion of ribonucleoside diphosphates to deoxyribonucleoside diphosphates. As expression levels of human RR (hRR) are high during cell replication, hRR has long been considered an attractive drug target for a range of proliferative diseases, including cancer. While there are many excellent reviews regarding the structure, function, and clinical importance of hRR, recent years have seen an increase in novel approaches to inhibiting hRR that merit an updated discussion of the existing inhibitors and strategies to target this enzyme. In this review, we discuss the mechanisms and clinical applications of classic nucleoside analog inhibitors of hRRM1 (large catalytic subunit), including gemcitabine and clofarabine, as well as inhibitors of the hRRM2 (free radical housing small subunit), including triapine and hydroxyurea. Additionally, we discuss novel approaches to targeting RR and the discovery of new classes of hRR inhibitors.

The marine factor 3,5-dihydroxy-4-methoxybenzyl alcohol suppresses growth, migration and invasion and stimulates death of metastatic human prostate cancer cells: targeting diverse signaling processes

Prostate cancer is metastatic cancer and is the second leading cause of cancer-related death in men. It is needed to develop more effective treatment for metastatic prostate cancer. The present study investigates whether the novel factor 3,5-dihydroxy-4-methoxybenzyl alcohol (DHMBA), which was isolated from marine oyster, suppresses the activity of metastatic human prostate cancer PC-3 or DU-145 cells. Culture of DHMBA (1 or 10 µM) suppressed colony formation and growth of PC-3 or DU-145 cells in vitro. Suppressive effects of DHMBA on cell proliferation were not occurred by culturing with intracellular signaling inhibitors. Mechanistically, DHMBA (10 µM) reduced the levels of key proteins linked to promotion of cell growth, including Ras, PI3K, Akt, MAPK, and mTOR in PC-3 cells. Interestingly, DHMBA increased the levels of cancer suppressor p53, p21, Rb, and regucalcin. Moreover, culture of DHMBA simulated the death of PC-3 and DU-145 cells. This effect was implicated to caspase-3 activation in cells. Interestingly, the effects of DHMBA on cell proliferation and death were blocked by culturing with an inhibitor of aryl hydrocarbon receptor linked to transcriptional regulation. Furthermore, culture of DHMBA inhibited production of reactive oxygen species in PC-3 or DU-145 cells. Of note, DHMBA blocked migration and invasion by diminishing their related protein levels, including NF-κB 65, caveolin-1 and integrin β1. The novel marine factor DHMBA was demonstrated to suppress metastatic prostate cancer cells via targeting diverse signaling pathways. This study may provide a new strategy for prostate cancer therapy with DHMBA.

Extracellular Regucalcin Suppresses the Growth, Migration, Invasion and Adhesion of Metastatic Human Prostate Cancer Cells

Regucalcin plays a multifunctional role in the regulation of cellular function including metabolism, signaling process and transcriptional activity in maintaining cell homeostasis. Downregulated expression or activity of regucalcin contributes to the development of malignancies in various types of human cancer. Survival of cancer patients, including metastatic prostate cancer, is prolonged with high expression of regucalcin in the tumor tissues. Furthermore, we elucidate whether extracellular regucalcin conquers the growth, migration, invasion and adhesion of metastatic human prostate cancer PC-3 and DU-145 cells. Extracellular regucalcin (0.1, 1, and 10 nM) of physiologic levels inhibited colony formation and growth of PC-3 and DU-145 cells, while it did not have an effect on cell death. Repressive effects of extracellular regucalcin on the proliferation were not exhibited by the presence of inhibitors of cell cycle, intracellular signaling process and transcriptional activity, suggesting that the signals of extracellular regucalcin are transmitted to block cell growth. Furthermore, extracellular regucalcin (0.1, 1, or 10 nM) inhibited migration, invasion and adhesion of PC-3 and DU-145 cells. Mechanistically, extracellular regucalcin (10 nM) decreased the levels of various signaling proteins including Ras, hosphatidylinositol-3 kinase, mitogen-activated protein kinase, mTOR, RSK-2, caveolin-1 and integrin β1 in PC-3 cells. Thus, extracellular regucalcin may play a suppressive role in growth, migration, invasion and adhesion, which are involved in metastatic activity of human prostate cancer cells, via affecting diverse signaling processes. This study may provide a new strategy in preventing metastatic prostate cancer with exogenous regucalcin.

The phytochemical p-hydroxycinnamic acid suppresses the growth and stimulates the death in human liver cancer HepG2 cells

Hepatocellular carcinoma (HCC) is one of the most prevalent malignant diseases and causes a third of cancer-related death. The prognosis and effective treatment of advanced HCC remains poor in spite of the development of novel therapeutic strategies. In the present study, we investigate anticancer effects of the botanical molecule p-hydroxycinnamic  acid (HCA) in the HepG2 liver cancer model in vitro. Culturing with HCA (10-1000 nM) suppressed colony formation and growth of HepG2 cells. Mechanistically, culturing with HCA decreased levels of Ras, PI3K, Akt, MAPK, NF-κB p65 and β-catenin, which are linked to processes of cell signaling and transcription, and increased levels of retinoblastoma and regucalcin, which are suppressors for carcinogenesis. These alterations may lead to the suppression of cell growth. Furthermore, culturing with HCA (10-1000 nM) stimulated cell death due to increased caspase-3 levels. Interestingly, the effects of HCA on the growth and death of HepG2 cells were inhibited by culturing with CH223191, an antagonist of aryl hydrocarbon receptor (AHR), suggesting that the flavonoid effects are, at least partly, mediated by activation of AHR signaling. Notably, HCA blocked stimulatory effects of Bay K 8644, an agonist of L-type calcium channel, on the growth of HepG2 cells. Thus, our study demonstrates that HCA suppresses the growth and stimulates the death of human liver cancer HepG2 cells in vitro. The botanical molecule HCA may therefore be a useful tool in the treatment of HCC, providing a novel strategy for the therapy of human liver cancers.

Thymoquinone Is a Multitarget Single Epidrug That Inhibits the UHRF1 Protein Complex

Silencing of tumor suppressor genes (TSGs) through epigenetic mechanisms, mainly via abnormal promoter DNA methylation, is considered a main mechanism of tumorigenesis. The abnormal DNA methylation profiles are transmitted from the cancer mother cell to the daughter cells through the involvement of a macromolecular complex in which the ubiquitin-like containing plant homeodomain (PHD), and an interesting new gene (RING) finger domains 1 (UHRF1), play the role of conductor. Indeed, UHRF1 interacts with epigenetic writers, such as DNA methyltransferase 1 (DNMT1), histone methyltransferase G9a, erasers like histone deacetylase 1 (HDAC1), and functions as a hub protein. Thus, targeting UHRF1 and/or its partners is a promising strategy for epigenetic cancer therapy. The natural compound thymoquinone (TQ) exhibits anticancer activities by targeting several cellular signaling pathways, including those involving UHRF1. In this review, we highlight TQ as a potential multitarget single epidrug that functions by targeting the UHRF1/DNMT1/HDAC1/G9a complex. We also speculate on the possibility that TQ might specifically target UHRF1, with subsequent regulatory effects on other partners.

The botanical component p-hydroxycinnamic acid suppresses the growth and bone metastatic activity of human prostate cancer PC-3 cells in vitro

Bone metastatic prostate cancer is one of the most common malignancies in developed countries and the second leading cause of cancer-related death in men. There remains no effective treatment for metastatic prostate cancer. We investigate here the anticancer effects of botanical component p-hydroxycinnamic acid (HCA) on the PC-3 cells in vitro model of bone metastatic human prostate cancer. Culturing with HCA (10-1000 nM) suppressed colony formation and growth of PC-3 cells. Mechanistically, culturing with HCA decreased protein levels of Ras, PI3K, Akt, MAPK, NF-κB p65 and β-catenin related to processes of cell signaling and transcription, and it increased levels of p21, p53, retinoblastoma and regucalcin, which are suppressors in carcinogenesis. These alterations can lead to suppression of cell growth. Furthermore, culturing with HCA increased cell death and caspase-3 levels. The effects of HCA on the growth and death of PC-3 cells were blocked by culturing with CH223191, an antagonist of aryl hydrocarbon receptor (AHR), suggesting that HCA effects are partly involved in AHR signaling. Interestingly, HCA suppressed the stimulatory effects of Bay K 8644, an agonist of L-type calcium channel, on the growth of PC-3 cells. Coculturing of PC-3 cells and preosteoblastic MC-3T3 E1 cells increased osteoblastic mineralization. This increase was not attenuated by treatment of HCA that stimulated mineralization. Notably, osteoclastogenesis from preosteoclastic RAW264.7 cells was enhanced by coculturing with PC-3 cells, and this enhancement was suppressed by treatment with HCA (10-1000 nM). Thus, HCA has anticancer effects on bone metastatic human prostate cancer, potentially providing a novel therapeutic tool.

Extracellular regucalcin suppresses colony formation and growth independent of tumor suppressor p53 in human mammary epithelial cells

Regucalcin plays a multifunctional role in cell regulation as a suppressor in the processes of intracellular signaling and transcription, leading to inhibition of cell growth. The downregulated expression or activity of regucalcin has been shown to contribute to the development of carcinogenesis in various types of human cancer. The wild-type tumor suppressor TP53 gene encodes for a transcriptional factor p53. This protein may play a role in cell proliferation. Loss of p53 function may induce cell transformation during carcinogenesis and tumor progression of human cancer. We investigate whether or not extracellular regucalcin suppresses the proliferation of non-tumorigenic human mammary epithelial MCF 10A cells with loss of p53 in vitro. Loss of p53 did not impact colony formation and proliferation of the cells. Interestingly, p53 loss caused decrease in the cell cycle suppressor p21, but not retinoblastoma and regucalcin, as compared with those of wild-type MCF 10A cells. Notably, extracellular regucalcin suppressed colony formation and proliferation of wild-type MCF 10A cells and p53 (-/-) cells, while it did not have an effect on cell death. Mechanistically, extracellular regucalcin decreased levels of various signaling factors including Ras, phosphatidylinositol-3 kinase, mitogen-activated protein kinase (MAPK), phospho-MAPK, and signal transducer and activator of transcription 3 in wild-type MCF 10A cells and p53 (-/-) cells. Thus, extracellular regucalcin was found to suppress the growth of MCF 10A cells with loss of p53. Extracellular regucalcin may play a role as a suppressor in the growth of human mammary epithelial cells with p53 loss, providing a novel strategy for cancer.

Anticancer effects of miR-124 delivered by BM-MSC derived exosomes on cell proliferation, epithelial mesenchymal transition, and chemotherapy sensitivity of pancreatic cancer cells

OBJECTIVE

This study aims to explore the roles of miR-124 in pancreatic tumor and potential vehicles.

RESULTS

The miR-124 expression levels decreased in pancreatic adenocarcinoma tissues and cancer cell lines AsPC-1, PANC1, BxPC-3 and SW1990. Furthermore, the elevated expression of miR-124 in AsPC-1 and PANC1 via miR-124 mimic transfection-induced apoptosis, metastasis and epithelial mesenchymal transition was suppressed, and the EZH2 overexpression partly reversed the protective effects of miR-124 against pancreatic tumors. In addition, the expression of miR-124 was detected in exosomes extracted from miR-124-transfected BM-MSCs, and these exosomes delivered miR-124 into pancreatic cancer cells, and presented the anti-tumor effects in vitro and in vivo.

CONCLUSION

MiR-124-carried BM-MSC-derived exosomes have potential applications for the treatment of pancreatic tumors.

METHODS

The expression of miR-124 and EZH2 was determined in both pancreatic cancer tissues and cell lines. miR-124 or EZH2 was overexpressed in AsPC-1 and PANC1 cells. Then, the effects on cell viability. apoptosis, invasion, migration and epithelial mesenchymal transition were evaluated. Afterwards, the roles of miR-124 on the expression and function of EZH2 in pancreatic tumors were determined by dual luciferase reporter assay. Subsequently, miR-124 was transfected to bone marrow mesenchymal stromal cells (BM-MSCs), and the BM-MSCs derived exosomes were isolated and co-cultured with AsPC-1 and PANC1 cells, or injected into pancreatic cancer tumor-bearing mice.

Parthenolide as Cooperating Agent for Anti-Cancer Treatment of Various Malignancies

Primary and acquired resistance of cancer to therapy is often associated with activation of nuclear factor kappa B (NF-κB). Parthenolide (PN) has been shown to inhibit NF-κB signaling and other pro-survival signaling pathways, induce apoptosis and reduce a subpopulation of cancer stem-like cells in several cancers. Multimodal therapies that include PN or its derivatives seem to be promising approaches enhancing sensitivity of cancer cells to therapy and diminishing development of resistance. A number of studies have demonstrated that several drugs with various targets and mechanisms of action can cooperate with PN to eliminate cancer cells or inhibit their proliferation. This review summarizes the current state of knowledge on PN activity and its potential utility as complementary therapy against different cancers.

Identifying Drug Targets in Pancreatic Ductal Adenocarcinoma Through Machine Learning, Analyzing Biomolecular Networks, and Structural Modeling

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death and has an extremely poor prognosis. Thus, identifying new disease-associated genes and targets for PDAC diagnosis and therapy is urgently needed. This requires investigations into the underlying molecular mechanisms of PDAC at both the systems and molecular levels. Herein, we developed a computational method of predicting cancer genes and anticancer drug targets that combined three independent expression microarray datasets of PDAC patients and protein-protein interaction data. First, Support Vector Machine–Recursive Feature Elimination was applied to the gene expression data to rank the differentially expressed genes (DEGs) between PDAC patients and controls. Then, protein-protein interaction networks were constructed based on the DEGs, and a new score comprising gene expression and network topological information was proposed to identify cancer genes. Finally, these genes were validated by “druggability” prediction, survival and common network analysis, and functional enrichment analysis. Furthermore, two integrins were screened to investigate their structures and dynamics as potential drug targets for PDAC. Collectively, 17 disease genes and some stroma-related pathways including extracellular matrix-receptor interactions were predicted to be potential drug targets and important pathways for treating PDAC. The protein-drug interactions and hinge sites predication of ITGAV and ITGA2 suggest potential drug binding residues in the Thigh domain. These findings provide new possibilities for targeted therapeutic interventions in PDAC, which may have further applications in other cancer types.

CTHRC1 affects malignant tumor cell behavior and is regulated by miR-30e-5p in human prostate cancer

Collagen Triple Helix Repeat Containing 1 (CTHRC1) has been picked out as a cancer-related, secreted glycoprotein that possesses multifaceted functions such as wound repair, the formation of adipose tissue, hepatocytes fibrosis, and bone remodeling. This study aims to explore the biological function and the profound regulative mechanism of CTHRC1 in human prostate cancer (PCa). We found that CTHRC1 was upregulated in patients with PCa. The knockdown of CTHRC1 suppressed PCa cell proliferation, invasion, migration, and colony formation significantly. The expression of CTHRC1 was down-regulated and up-regulated by miR-30e-5p mimics and inhibitors, respectively, in PCa cells. The dual-luciferase reporter assay validated the binding of miR-30e-5p with CTHRC1 mRNA, indicating the regulation of CTHC1 by miR-30e-5p. In consequence, this study demonstrated that CTHRC1 acts as an oncogenic gene and targeting the miR-30e-5p-CTHRC1 axis may provide novel therapeutic treatment for PCa.

Overexpression of Regucalcin Suppresses the Growth of Human Osteosarcoma Cells in Vitro: Repressive Effect of Extracellular Regucalcin

Regucalcin plays a pivotal role as a suppressor of human carcinogenesis, and downregulation of regucalcin expression may contribute to the promotion of human osteosarcoma. Overexpression of regucalcin suppressed the proliferation of Saos-2 human osteosarcoma cells in vitro and decreased the protein levels of multiple signaling components, transcription factors, and tumor suppressors. Interestingly, extracellular regucalcin repressed colony formation and proliferation of Saos-2 cells, and reduced the protein levels of multiple signaling components, cell cycle inhibitor, and various transcription factors. Thus, regucalcin suppressed the growth of human osteosarcoma cells, providing a novel strategy with the gene therapy for treatment of osteosarcoma.

Cancer stem cells as therapeutic targets of pancreatic cancer

The discovery of stem cells and their potential abilities in self-renewal and differentiation has opened a new horizon in medicine. Scientists have found a small population of stem cells in some types of cancers with the same functions as normal stem cells. There are two models for tumor progression: clonal (stochastic) and cancer stem cell (CSCs) models. According to the first model, all transformed cells in the tumor have carcinogenic potential and are able to proliferate and produce the same cells. The latter model, which has received more attention recently, considers the role of CSCs in drug resistance and tumor metastasis. Following the model, researchers have found that targeting CSCs may be a promising way in cancer therapy. This review describes CSC characteristics in general, while also focusing on CSC properties in the context of pancreatic cancer.

CTHRC1 May Serve As A Prognostic Biomarker For Hepatocellular Carcinoma

Background

Hepatocellular carcinoma is a common malignant cancer and the second most common cause of cancer-related deaths worldwide. Collagen triple helix repeat containing 1 (CTHRC1) has been increasingly reported to be involved in tumorigenesis and/or tumor progression. However, limited data are available regarding the role of CTHRC1 in hepatocellular carcinoma.

Methods

Paraffin-embedded specimens from a total of 29 patients with HCC were collected in our study. The expression of CTHRC1 in hepatocellular carcinoma was evaluated using immunohistochemistry and bioinformatics analysis. Furthermore, Spearman analysis was performed to identify factors of correlation between CTHRC1 and clinicopathological features. Survival curves for hepatocellular carcinoma were produced using the Kaplan-Meier method and the log rank test.

Results

In this study, we confirmed that CTHRC1 is highly expressed in tissues and hepatoma cell lines. The statistical analysis revealed that the levels of CTHRC1 were significantly correlated with cirrhosis (P=0.024), tumor size (P=0.006), vascular invasion (P<0.001), TNM stage (P<0.001), and BCLC stage (P<0.001). High expression of CTHRC1 in hepatocellular carcinoma tissues is significantly associated with poor survival.

Conclusion

CTHRC1 may serve as a prognostic biomarker for hepatocellular carcinoma.

Survival-Associated Alternative Messenger RNA Splicing Signatures in Pancreatic Ductal Adenocarcinoma: A Study Based on RNA-Sequencing Data

Multiple studies have shown that cancer-specific alternative splicing (AS) alterations are associated with clinical outcome. In this study, we aimed to profile prognostic AS signatures for pancreatic ductal adenocarcinoma (PDAC). We integrated the percent-spliced-in (PSI) data of AS in 140 PDAC patients based on the Cancer Genome Atlas (TCGA) dataset. We identified overall survival (OS)-associated AS events using univariate Cox regression analysis. Then, prognostic AS signatures were constructed for OS and chemoresistance prediction using the least absolute shrinkage and selection operator (LASSO) method. We also analyzed splicing factors (SFs) regulatory networks by Pearson's correlation. We detected 677 OS-related AS events in 485 genes by profiling 10,354 AS events obtained from 140 PDAC patients. Gene functional enrichment analysis demonstrated the pathways enriched by survival-associated AS. The AS signatures constructed with significant survival-associated AS events revealed high performance in predicting PDAC survival and gemcitabine chemoresistance. The area under the receiver operator characteristic curve was 0.937 in training cohort and 0.748 in validation cohort at 2000 days of OS. Furthermore, we identified prognostic SFs (e.g., ESRP1 and HNRNPC) to build the AS regulatory network. We constructed AS signatures for OS and gemcitabine chemoresistance in PDAC patients, which may provide clues for further experiment-based mechanism study.

Long non-coding RNA LINC01207 silencing suppresses AGR2 expression to facilitate autophagy and apoptosis of pancreatic cancer cells by sponging miR-143-5p

Pancreatic cancer is a serious malignancy accompanied by a well-documented poor prognosis. Accumulating studies have indicated the crucial roles played by long non-coding RNAs (lncRNAs) in proliferation, apoptosis and invasion of cancer cells. The aim of the current study was to investigate the role of lncRNA LINC01207 in autophagy and apoptosis of pancreatic cancer cells and its regulatory mechanism interacting with miR-143-5p. Initially, expression profiles of lncRNAs and genes associated with pancreatic cancer were identified. The expression patterns of LINC01207, miR-143-5p and AGR2 in both pancreatic cancer and adjacent tissues were then determined. The binding relationship of LINC01207 to miR-143-5p and targeting relationship of miR-143-5p to AGR2 were subsequently verified. Silencing of LINC01207, or up-regulation or down-regulation of miR-143-5p was introduced into the pancreatic cancer cells, so as to analyze their effects on the cell growth, apoptosis and autophagy. Besides, these regulatory effects were further explored with the determination of the autophagy- and apoptosis-related gene or proteins. LINC01207 and AGR2 were highly expressed while miR-143-5p was poorly expressed in pancreatic cancer. Functionally, LINC01207 can bind to miR-143-5p, and AGR2 was a target gene of miR-143-5p. Importantly, silencing of LINC01207 down-regulated the expression of AGR2 by up-regulating miR-143-5p. Moreover, silencing of LINC01207 and up-regulation of miR-143-5p promoted cell apoptosis and autophagy, corresponding to increased expression of autophagy- and apoptosis-related proteins, in addition to inhibited cell growth. Taken together, silencing of LINC01207 prevents the progression of pancreatic cancer by impairing miR-143-5p-targeted AGR2 expression, providing a potential target for pancreatic cancer treatment.

Zinc chelator TPEN induces pancreatic cancer cell death through causing oxidative stress and inhibiting cell autophagy

The essential trace element zinc (Zn) is widely required in cellular functions, and abnormal Zn homeostasis causes a variety of health problems including immunodeficiency and sensory dysfunctions. Previous studies had shown that Zn availability was also important for tumor growth and progression. The aim of the present study was to investigate the potential mechanisms of N,N,N,N-Tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN) (a membrane permeable zinc chelator) induced pancreatic cancer cell death. The text of inductively coupled plasma-mass spectrometry (ICP-MS) showed in human pancreatic cancer samples that the zinc content in cancer was higher than that in adjacent tissues. The pancreatic cancer cell lines Panc-1, 8988T, BxPc-3, and L3.6 were used in this study. Our results indicated that TPEN markedly induced cell death, via increasing reactive oxygen species (ROS) and restraining autophagy. Our data also indicated that TPEN-stimulated mitochondrial metabolism produced much ROS. Meanwhile, TPEN reduced the levels of glutathione (GSH) and triggered ROS outbreak, which were the main causes of cell death. In addition, cell autophagy was significantly depressed in Panc-1 cells treated by TPEN, which was due to the ability of disrupting lysosomal by TPEN. Thus, we thought zinc depletion by TPEN was a potential therapeutic strategy for pancreatic cancer.

Curcumin analogs: Their roles in pancreatic cancer growth and metastasis

Curcumin is a polyphenolic constituent of turmeric that is known to have various molecular effects in preclinical models, leading to prevention and anticancer properties. In clinical trials, curcumin has failed to demonstrate activity against pancreatic cancer possibly due to its low bioavailability and potency. Using the curcumin molecular model, our group and others have synthesized several analogs with better bioavailability and higher potency in pancreatic cancer in vitro and xenograft models. This mini review summarizes some of the known molecular effects of curcumin analogs and their potential role as novel therapeutics for pancreatic cancer.

Prolonged survival of renal cancer patients is concomitant with a higher regucalcin gene expression in tumor tissues: Overexpression of regucalcin suppresses the growth of human renal cell carcinoma cells in vitro

Renal cell carcinoma (RCC), which is a type of cancer found in the kidney tubule, is among the 10 most frequently occurring human cancers. Regucalcin plays a potential role as a regulator of transcriptional activity, and its downregulated expression or activity may contribute to the promotion of human cancers. In this study, we investigated the involvement of regucalcin in human RCC. Regucalcin expression was compared in 23 normal and 29 tumor samples of kidney cortex tissues of patients with clear cell RCC obtained through the Gene Expression Omnibus (GEO) database (GSE36895). Regucalcin expression was downregulated in the tumor tissues. The prolonged survival of patients with clear cell RCC was demonstrated to be associated with a higher regucalcin gene expression in the TCGA dataset. The overexpression of regucalcin suppressed the colony formation, proliferation and the death of human clear cell RCC A498 cells in vitro. Mechanistically, the overexpression of regucalcin induced the G1 and G2/M phase cell cycle arrest of A498 cells through the suppression of multiple signaling components, including Ras, PI3 kinase, Akt and mitogen‑activated protein (MAP) kinase. Importantly, the overexpression of regucalcin led to an elevation in the levels of the tumor suppressors, p53, Rb and the cell cycle inhibitor, p21. The levels of the transcription factors, c‑fos, c‑jun, nuclear factor‑κB p65, β‑catenin and signal transducer and activator of transcription 3, were suppressed by regucalcin overexpression. On the whole, the findings of this study suggest that regucalcin plays a suppressive role in the promotion of human RCC. The overexpression of regucalcin by gene delivery systems may thus prove to be a novel therapeutic strategy for RCC.

2,3,7,8‑Tetrachlorodibenzo‑p‑dioxin suppresses the growth of human liver cancer HepG2 cells in vitro: Involvement of cell signaling factors

The aryl hydrocarbon receptor (AHR) is transcriptionally active in the form of a heterodimer with the AHR nuclear translocator, which then binds to the xenobiotic responsive element. AHR was originally discovered via its ligand, the polychlorinated hydrocarbon, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we investigated whether TCDD regulates the growth of human liver cancer HepG2 cells in vitro. TCDD (0.1–100 nM) was found to exert suppressive effects on the colony formation and proliferation of HepG2 cells, and stimulatory effects on the death of HepG2 cells when the cells reached subconfluence. The effects of TCDD on the HepG2 cells were abolished by culture with CH223191, an inhibitor of AHR signaling. The effects of TCDD were dependent on the concentration of serum, which contains various signaling factors. The effects of TCDD were not potentiated by culture with tumor necrosis factor-α, which activates the signaling of nuclear factor-κB (NF-κB). The results of western blot analysis revealed that TCDD increased the protein levels of p53, Rb, p21, and regucalcin, which are suppressors of the growth of tumor cells. Moreover, TCDD enhanced the NF-κB p65, β-catenin, signal transducer and activator of transcription 3 (STAT3), Ras and Akt levels. Thus, the findings of this study indicate that TCDD may suppress liver cancer cell growth through various signaling pathways, mediated by AHR and its-related co-factors. Of note, the effects of TCDD were found to be potentiated by gemcitabine, which induces nuclear DNA damage in cancer cells, suggesting that their combined use may have potential as a suppressor of tumor cell growth.

Prolonged survival of patients with colorectal cancer is associated with a higher regucalcin gene expression: Overexpression of regucalcin suppresses the growth of human colorectal carcinoma cells in vitro

Regucalcin plays a crucial role as a regulator of transcriptional signaling activity, and its decreased expression or activity may contribute to the promotion of human carcinogenesis. A higher regucalcin expression in the tumor tissues has been demonstrated to prolong the survival of patients with various types of cancer, including pancreatic cancer, breast cancer, liver cancer and lung adenocarcinoma. The involvement of regucalcin in human colorectal cancer was investigated in the current study. Regucalcin gene expression and the survival data of 62 patients with colorectal cancer were obtained though the Gene Expression Omnibus (GEO) database (GSE12945) for outcome analysis. The data of gene expression revealed that the prolonged survival of patients with colorectal cancer was associated with a higher regucalcin gene expression in tumor tissues. The overexpression of regucalcin suppressed colony formation and proliferation, and induced the death of human colorectal carcinoma RKO cells cultured in a medium containing fetal bovine serum in vitro. Mechanistically, the overexpression of regucalcin induced the G1 and G2/M phase cell cycle arrest of the RKO cells through the suppression of multiple signaling pathways, including Ras, Akt, mitogen-activated protein (MAP) kinase and SAPK/JNK. Of note, the overexpression of regucalcin induced an increase in the levels of the tumor suppressors, p53 and Rb, and the cell cycle inhibitor, p21. Moreover, the levels of the transcription factors, c‑fos, c‑jun, nuclear factor (NF)‑κB p65, β-catenin and signal transducer and activator of transcription 3 (Stat3), were suppressed by the overexpression of regucalcin. On the whole, the findings of this study suggest that regucalcin plays a crucial role as a suppressor in human colorectal cancer, and that the suppressed expression of the regucalcin gene may predispose patients to the promotion of colorectal cancer. The overexpression of regucalcin by gene delivery may thus prove to be a novel therapeutic strategy for colorectal cancer.

Imaging of Claudin-4 in Pancreatic Ductal Adenocarcinoma Using a Radiolabelled Anti-Claudin-4 Monoclonal Antibody

PURPOSE

Despite its widespread use, the positron emission tomography (PET) radiotracer 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) has been shown in clinical settings to be ineffective for improving early diagnosis of pancreatic ductal adenocarcinoma (PDAC). A promising biomarker for PDAC detection is the tight junction protein claudin-4. The purpose of this study was to evaluate a new single-photon emission computed tomography (SPECT) imaging agent, [111In]anti-claudin-4 mAb, with regard to its ability to allow visualisation of claudin-4 in a xenograft and a genetically engineered mouse model of PDAC.

PROCEDURES

The ability of [111In]anti-claudin-4 mAb to selectively target claudin-4 was assessed using two human xenograft tumour models with differential claudin-4 status in mice. [111In]anti-claudin-4 mAb was also used to detect PDAC development in genetically engineered KPC mice. The PDAC status of these mice was confirmed with [18F]FDG-PET, magnetic resonance imaging (MRI), histology, and immunofluorescence microscopy.

RESULTS

High uptake of [111In]anti-claudin-4 mAb was observed in PDAC xenografts in mice, reaching 16.9 ± 4.5 % of injected dose per gram (% ID/g) at 72 h post-injection. This uptake was mediated specifically by the expression of claudin-4. Uptake of [111In]anti-claudin-4 mAb also enabled clear visualisation of spontaneous PDAC formation in KPC mice.

CONCLUSIONS

[111In]anti-claudin-4 mAb allows non-invasive detection of claudin-4 upregulation during development of PDAC and could potentially be used to aid in the early detection and characterisation of this malignancy.

Gene microarray analysis of lncRNA and mRNA expression profiles in patients with high‑grade ovarian serous cancer

High-grade ovarian serous cancer is known for its high rates of invasion and metastasis, and resultant high mortality rate. Therefore, research concerning biomarkers and underlying molecular mechanisms of high-grade ovarian serous cancer progression and prognosis are urgently required. Long non-coding RNAs (lncRNAs) have been the subject of an increasing number of studies, and certain lncRNAs have been demonstrated to serve an important function in the development and progression of various cancers, including HOX transcript antisense RNA, competing endogenous lncRNA 2 for microRNA let-7b, urothelial cancer associated 1, and H19, imprinted maternally expressed transcript (non-protein coding). However, few studies have investigated the differential expression of lncRNAs in high-grade ovarian serous cancer. In the present study, differences in lncRNA and mRNA expression profiles between high-grade ovarian serous cancer tissue samples and healthy fallopian tube tissue samples were investigated using microarray analysis, and the differential expression of lncRNAs and mRNAs was confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Then, five abnormally expressed lncRNAs were selected, and the associations between these lncRNAs and ovarian cancer clinicopathological parameters were examined using RT-qPCR. The expression profiles of certain lncRNAs and mRNAs were confirmed to be altered between high-grade ovarian serous cancer tissues and healthy fallopian tube tissues. Furthermore, the expression levels of selected lncRNAs were associated with International Federation of Gynecology and Obstetrics stage and lymph node metastasis. These lncRNAs and mRNAs may therefore be involved in the pathogenesis of high-grade ovarian serous cancer. The results of the present study provide an experimental foundation for further exploration of the value of these lncRNAs and mRNAs in the early diagnosis and treatment of high-grade ovarian serous cancer.

Investigating the role of transcription factors of pancreas development in pancreatic cancer

Pancreatic cancer (PC) is the seventh most common cause of cancer-related deaths worldwide that kills more than 300,000 people every year. Prognosis of PC is very poor with a five-year survival rate about 5%. The most common and highly observed type of PC is pancreatic ductal adenocarcinoma (PDAC). It is preceded by the progression of precursor lesions such as Pancreatic Intraepithelial Neoplasia (PanIN), Intraductal Papillary Neoplasm (IPMN) and Mucinous Cystic Neoplasm (MCN). PanIN is the most common among these premalignant lesions. Genes orchestrating the origin and differentiation of cells during organogenesis have the tendency to produce tumor cells in response to activating or inactivating mutations. Based on the following premise, we discuss the role of transcription factors (TFs) of pancreas development and cell fate differentiation in PC. Pancreas/duodenum homeobox protein 1 (PDX1), Pancreas transcription factor 1 subunit alpha (PTF1A), Nuclear receptor subfamily 5 group A member 2 (NR5A2), Hepatocyte nuclear factor 1-alpha (HNF1A) and Hepatocyte nuclear factor 1-beta (HNF1B) play vital role in the development and differentiation of pancreatic precursor cells. Mutated KRAS induces abnormalities in the regular function of these TFs which in turn cause abnormal cell growth and proliferation that leads to cancer. Thus, these TFs are highly susceptible for the origin of PC. Therefore, we propose that these TFs can be treated as therapeutic targets for the development of anticancer drugs.

Disorders noticed during development of pancreatic cancer: potential opportunities for early and effective diagnostics and therapy

Pancreatic cancer, with a total five-year survival rate below 5%, represents a disease with a high level of malignancy. Some of the pancreatic cancer bad prognosis factors are nutrition disorders. Malnutrition, neither recognized nor properly referred to by the healthcare system, leads to well-documented negative health consequences in hospitalized patients including their impaired immunity, delayed post-surgery wound healing, a high risk of infectious complications, morbidity and mortality. There are numerous factors contributing to the development of pancreatic cancer, including telomerases, inflammation, angiogenesis, epigenetics and genetics factors, miRNA, pancreatic cancer stem cells. On the basis of molecular analyses, it has been established that precursor injuries may trigger pancreatic cancer when added to genetic alterations. Perhaps, combination of few presently used methods, like signal transduction modulated by K-ras, STAT3 activation, HMGB1 releasing, presence of oxidative stress and free radicals secretion, genes for proangiogenic growth factors activation or tissue-specific miRNA genes expression - will solve the problem of inadequate diagnostics.

Collecting duct carcinoma of the kidney is associated with CDKN2A deletion and SLC family gene up-regulation

The genetic landscape and molecular features of collecting duct carcinoma (CDC) of the kidney remain largely unknown. Herein, we performed whole exome sequencing (WES) and transcriptome sequencing (RNASeq) on 7 CDC samples (CDC1 −7). Among the 7 samples, 4 samples with matched non-tumor tissue were used for copy number analysis by SNP array data. No recurrent somatic SNVs were observed except for MLL, which was found to be mutated (p.V297I and p.F407C) in 2 samples. We identified somatic SNVs in 14 other cancer census genes including: ATM, CREBBP, PRDM1, CBFB, FBXW7, IKZF1, KDR, KRAS, NACA, NF2, NUP98, SS18, TP53, and ZNF521. SNP array data identified a CDKN2A homozygous deletion in 3 samples and SNV analysis showed a non-sense mutation of the CDKN2A gene with unknown somatic status. To estimate the recurrent rate of CDKN2A abnormalities, we performed FISH screening of additional samples and confirmed the frequent loss (62.5%) of CDKN2A expression. Since cisplatin based therapy is the common treatment option for CDC, we investigated the expression of solute carrier (SLC) family transporters and found 45% alteration. In addition, SLC7A11 (cystine transporter, xCT), a cisplatin resistance associated gene, was found to be overexpressed in 4 out of 5 (80%) cases of CDC tumors tested, as compared to matched non-tumor tissue. In summary, our study provides a comprehensive genomic analysis of CDC and identifies potential pathways suitable for targeted therapies.

The lncRNA-HOXA-AS2/EZH2/LSD1 oncogene complex promotes cell proliferation in pancreatic cancer

Emerging evidence have indicated that long non-coding RNAs (lncRNAs) play crucial roles in cancer development and progression. Previous studies have suggested that lncRNA-HOXA cluster antisense RNA 2 (HOXA-AS2) is involved in tumorigenesis of several cancers. However, little is known about the alteration and biological functions of HOXA-AS2 in pancreatic cancer (PC). The purpose of this study is to identify the role of HOXA-AS2 in PC. Here, we provided evidence that lncRNA HOXA-AS2 was up-regulated in PC tissues. In addition, Loss-of-function experiments revealed that HOXA-AS2 knockdown effectively suppressed proliferation by blocking the cell cycle transition and caused apoptosis of PC cells in vitro and in vivo. Mechanistically, we found that HOXA-AS2 directly interacted with enhancer of zeste homolog 2 (EZH2) and lysine specific demethylase 1 (LSD1), which promoted PC cell growth ability. Collectively, our findings demonstrated that lncRNA-HOXA-AS2/EZH2/LSD1 complex may function as an oncogene in PC cell proliferation, and also provides a potential therapy target for PC.

Proteinase-Activated Receptor 2 May Drive Cancer Progression by Facilitating TGF-β Signaling

The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer, it usually acts as a driver of cancer progression in various tumor types by promoting invasion and metastasis in response to activation by serine proteinases. Recently, we discovered another mode through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-β (TGF-β) signaling to promote TGF-β1-induced cell migration/invasion and invasion-associated gene expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is known about the cellular TGF-β responses and signaling pathways affected by PAR2 expression, the signaling activities of PAR2 required for promoting TGF-β signaling, and the potential molecular mechanism(s) that underlie(s) the TGF-β signaling-promoting effect. Since PAR2 is activated through various serine proteinases and biased agonists, it may couple TGF-β signaling to a diverse range of other physiological processes that may or may not predispose cells to cancer development such as local inflammation, systemic coagulation and pathogen infection.

Sclareolide enhances gemcitabine‑induced cell death through mediating the NICD and Gli1 pathways in gemcitabine‑resistant human pancreatic cancer

Pancreatic cancer is a type of cancer, which rapidly develops resistance to chemotherapy. Gemcitabine is the treatment used clinically, however, gemcitabine resistance leads to limited efficacy and patient survival rates of only a few months following diagnosis. The aim of the present study was to investigate the mechanisms underlying gemcitabine resistance in pancreatic cancer and to select targeted agents combined with gemcitabine to promote the treatment of pancreatic cancer. Panc-1 and ASPC-1 human pancreatic cancer cells (HPCCs) were used to establish the experimental model, and HPCCs were exposed to gemcitabine of serially increased concentrations to generate gemcitabine-resistant cells (GR-HPCCs). The anticancer effect of gemcitabine combined with sclareolide was then assessed. Epithelial to mesenchymal transition (EMT), human equilibrative nucleoside transporter 1 (hENT1) and ribonucleoside diphosphate reductase 1 (RRM1) were detected in the HPCCs and GR-HPCCs, and the mechanisms were investigated. Sclareolide resensitized the GR-HPCCs to gemcitabine. The expression levels of hENT1 and RRM1 were lower and higher, respectively, in GR-HPCCs, compared with HPCCs. Sclareolide upregulated hENT1, downregulated RRM1 and inhibited gemcitabine-induced EMT through the TWIST1/Slug pathway in the GR-HPCCs. In addition, sclareolide mediated the NOTCH 1 intracellular cytoplasmic domain (NICD)/glioma-associated oncogene 1 (Gli1) pathway, which triggered TWIST1/Slug-hENT1/RRM1 signaling and resensitized GR-HPCCs to gemcitabine. Finally, sclareolide resensitized GR-HPCCs to gemcitabine through inducing apoptosis; in vivo, the co-administraion of sclareolide and gemcitabine effectively suppressed tumor growth. Sclareolide may be a novel agent in combination with gemcitabine for the treatment of gemcitabine-resistant pancreatic cancer, which resensitizes GR-HPCCs to gemcitabine through mediating NICD and Gli1.

Survival of lung cancer patients is prolonged with higher regucalcin gene expression: suppressed proliferation of lung adenocarcinoma A549 cells in vitro

Regucalcin plays a crucial role as a suppressor of transcription signaling, and its diminished expression or activity may play a key role in human carcinogenesis. Higher regucalcin expression has been demonstrated to prolong survival of the patients of pancreatic cancer, breast cancer, and hepatocellular carcinoma. Moreover, we investigated an involvement of regucalcin in human lung cancer. Human non-small cell lung cancer (NSCLC) accounts for over 80% in human lung cancer and is one of the leading causes of malignancy-related mortality with fewer than 16% patients surviving beyond 5 years. In this study, gene expression and survival data of 204 lung adenocarcinoma patients were obtained through the gene expression omnibus database (GSE31210) for outcome analysis. Gene expression data demonstrated that prolonged survival in lung cancer patients is associated with higher regucalcin gene expression. Overexpression of regucalcin suppressed the proliferation, cell death, and migration of human lung adenocarcinoma NSCLC A549 cells in vitro. Mechanistically, regucalcin induced G1 and G2/M phase cell cycle arrest of A549 cells through suppression of multiple signaling pathways including Ras, Akt, MAP kinase, and SAPK/JNK. Moreover, overexpression of regucalcin caused decreases in the oncogenes c-fos and c-myc and elevation of the tumor suppressers p53 and Rb. These findings suggest that regucalcin may play a potential role as a suppressor of human lung cancer, and that downregulation of regucalcin expression may predispose patients to development of lung cancer. Overexpression of regucalcin using gene delivery may constitute a novel therapeutic approach to treating lung cancer.

Nanotechnology for delivery of gemcitabine to treat pancreatic cancer

Pancreatic cancer (PC) is one of the most deadly and quickly fatal human cancers with a 5-year mortality rate close to 100%. Its prognosis is very poor, mainly because of its hostile biological behavior and late onset of symptoms for clinical diagnosis; these bring limitations on therapeutic interventions. Factors contributing for the difficulties in treating PC include: high rate of drug resistance, fast metastasis to different organs, poor prognosis and relapse of the tumor after therapy. After being approved by US FDA 1997, Gemcitabine (Gem) is the first line and the gold standard drug for all stages of advanced PC till now. However, its efficacy is unsatisfactory, mainly due to; its chemical instability and poor cellular uptake, resulting in an extremely short half-life and low bioavailability. To solve this drawbacks and increase the therapeutic outcome important progress has been achieved in the field of nanotechnology and offers a promising and effective alternative. This review mainly focus on the most commonly investigated nanoparticle (NP) delivery systems of Gem for PC treatment and the latest progresses achieved. Novel nanocarriers with better tumor targeting efficiencies and maximum treatment outcome to treat this deadly due are given much attention.

Proteinase-Activated Receptor 2 Is a Novel Regulator of TGF-β Signaling in Pancreatic Cancer

TGF-β has a dual role in tumorigenesis, acting as a tumor suppressor in normal cells and in the early stages of tumor development while promoting carcinogenesis and metastasis in advanced tumor stages. The final outcome of the TGF-β response is determined by cell-autonomous mechanisms and genetic alterations such as genomic instability and somatic mutations, but also by a plethora of external signals derived from the tumor microenvironment, such as cell-to-cell interactions, growth factors and extracellular matrix proteins and proteolytic enzymes. Serine proteinases mediate their cellular effects via activation of proteinase-activated receptors (PARs), a subclass of G protein-coupled receptors that are activated by proteolytic cleavage. We have recently identified PAR2 as a factor required for TGF-β1-dependent cell motility in ductal pancreatic adenocarcinoma (PDAC) cells. In this article, we review what is known on the TGF-β-PAR2 signaling crosstalk and its relevance for tumor growth and metastasis. Since PAR2 is activated through various serine proteinases, it may couple TGF-β signaling to a diverse range of other physiological processes, such as local inflammation, systemic coagulation or pathogen infection. Moreover, since PAR2 controls expression of the TGF-β type I receptor ALK5, PAR2 may also impact signaling by other TGF-β superfamily members that signal through ALK5, such as myostatin and GDF15/MIC-1. If so, PAR2 could represent a molecular linker between PDAC development and cancer-related cachexia.

Analysis of Important Gene Ontology Terms and Biological Pathways Related to Pancreatic Cancer

Pancreatic cancer is a serious disease that results in more than thirty thousand deaths around the world per year. To design effective treatments, many investigators have devoted themselves to the study of biological processes and mechanisms underlying this disease. However, it is far from complete. In this study, we tried to extract important gene ontology (GO) terms and KEGG pathways for pancreatic cancer by adopting some existing computational methods. Genes that have been validated to be related to pancreatic cancer and have not been validated were represented by features derived from GO terms and KEGG pathways using the enrichment theory. A popular feature selection method, minimum redundancy maximum relevance, was employed to analyze these features and extract important GO terms and KEGG pathways. An extensive analysis of the obtained GO terms and KEGG pathways was provided to confirm the correlations between them and pancreatic cancer.

High expression of CTHRC1 promotes EMT of epithelial ovarian cancer (EOC) and is associated with poor prognosis

Collagen triple helix repeat-containing 1 (CTHRC1) is aberrantly overexpressed in multiple malignant tumors. However, the expression characteristics and function of CTHRC1 in epithelial ovarian cancer (EOC) remain unclear. We found that CTHRC1 expression was up-regulated in the paraffin-embedded EOC tissues compared to borderline or benign tumor tissues. CTHRC1 expression was positively correlated with tumor size (p = 0.008), menopause (p = 0.037), clinical stage (p = 0.002) and lymph node metastasis (p < 0.001) and was also an important prognostic factor for the overall survival of EOC patients, as revealed by Kaplan-Meier analysis. CTHRC1 increased the invasive capabilities of EOC cells in vitro by activating the Wnt/β-catenin signaling pathway. We showed that ectopic transfection of CTHRC1 in EOC cells up-regulated the expression of EMT markers such as N-cadherin and vimentin, and EMT-associated transcriptional factor Snail. Knockdown of CTHRC1 expression in EOC cells resulted in down-regulation of N-cadherin, vimentin, Snail and translocation of β-catenin. Collectively, CTHRC1 may promote EOC metastasis through the induction of EMT process and serve as a potential biomarker for prognosis as well as a target for therapy.

Notch4 inhibition reduces migration and invasion and enhances sensitivity to docetaxel by inhibiting Akt/fascin in pancreatic cancer cells

Overexpression of Notch4 is associated with a variety of tumor types. Only sparse information exists on Notch4 expression in pancreatic cancer (PC). The present study demonstrated that Notch4 expression was significantly upregulated in PC cell lines compared with a non-transformed pancreatic epithelial cell line, HPDE6c-7. To investigate the possible role of Notch4 in PC cells, an RNA interference approach was used to silence Notch4 expression. The results revealed that small interfering RNA (siRNA) targeting Notch4 significantly impeded the viability, migration and invasion abilities of PC cells in vitro. Downregulation of Notch4 with siRNA sensitized cells to the action of docetaxel. Furthermore, Notch4 downregulation enhanced the inhibition of Akt activation and the fascin expression induced by docetaxel in PC cells. Together, these data provide insight into the function of Notch4 and suggest that Notch4 may represent a new potential target for gene therapy in PC.

Prolonged survival in hepatocarcinoma patients with increased regucalcin gene expression: HepG2 cell proliferation is suppressed by overexpression of regucalcin in vitro

Hepatocellular carcinoma (HCC) is one of the most common malignant cancers worldwide and ranks third in overall global cancer-related mortality rates. Importantly, in this study gene expression data demonstrate that prolonged survival in HCC patients is associated with increased regucalcin gene expression. Regucalcin has been shown to play a pivotal role as a transcription repressor and diminished expression or activity of regucalcin may play a key role in the development of human carcinogenesis. Indeed, overexpression of regucalcin suppressed the proliferation, cell death, and migration of human HCC HepG2 cells in vitro. Mechanistically, regucalcin induced G1 and G2/M phase cell cycle arrest of HepG2 cells through suppression of multiple signaling pathways including Ras, Akt, MAP kinase and SAPK/JNK and by increasing the tumor suppressors p53 and Rb. Furthermore, the oncogenes c-fos and c-myc were suppressed by overexpression of regucalcin, and overexpression of regucalcin caused an increase in p21 and a decrease in NF-κB p65 and β-catenin. These findings suggest that regucalcin may play a potential role as a suppressor of human HCC, and that diminished expression of regucalcin may predispose patients to development of HCC. Overexpression of regucalcin may constitute a novel therapeutic approach to treating HCC.

Antitumor effects of the hyaluronan inhibitor 4-methylumbelliferone on pancreatic cancer

Hyaluronan (HA) is a major component of the extracellular matrix (ECM), and influences tumor invasion and metastasis. In a previous study, the present authors reported for the first time that 4-methylumbelliferone (MU) inhibited HA synthesis and suppressed tumor growth. However, the localization of HA and the changes in ECM morphology caused by MU in pancreatic cancer remain to be examined in detail. In the present study, the cytotoxicity of MU and its effect on cellular proliferation was evaluated in the human pancreatic cancer cell line MIA PaCa-2. The amount of HA synthesized and the retention of HA around the cells were quantitatively and immunohistochemically analyzed in vitro and in vivo. Structural changes in the ECM in the tumor tissue were investigated using an electron microscope. MU treatment led to a decrease in extracellular HA retention, as evidenced by a particle exclusion assay and immunohistochemical staining. Cell proliferation was suppressed by MU in a dose-dependent manner. The release of lactate dehydrogenase into the culture medium due to damage to the cellular membrane did not increase following MU administration. In tumor-inoculated mice, MU suppressed any increase in tumor volume and decreased the quantity of HA. Electron microscopy revealed that MU attenuated the intercellular space and caused it to be less cohesive. These data indicate that MU inhibits HA synthesis and reduces the amount of HA in the ECM while exhibiting no obvious cytotoxic effect. These findings suggest that MU has potential as a novel therapeutic agent for pancreatic cancer.

Cancer of the Pancreas: Molecular Pathways and Current Advancement in Treatment

Pancreatic cancer is one of the most lethal cancers among all malignances, with a median overall survival of <1 year and a 5-year survival of ~5%. The dismal survival rate and prognosis are likely due to lack of early diagnosis, fulminant disease course, high metastasis rate, and disappointing treatment outcome. Pancreatic cancers harbor a variety of genetic alternations that render it difficult to treat even with targeted therapy. Recent studies revealed that pancreatic cancers are highly enriched with a cancer stem cell (CSC) population, which is resistant to chemotherapeutic drugs, and therefore escapes chemotherapy and promotes tumor recurrence. Cancer cell epithelial to mesenchymal transition (EMT) is highly associated with metastasis, generation of CSCs, and treatment resistance in pancreatic cancer. Reviewed here are the molecular biology of pancreatic cancer, the major signaling pathways regulating pancreatic cancer EMT and CSCs, and the advancement in current clinical and experimental treatments for pancreatic cancer.

Potential suppressive effects of gentian violet on human breast cancer MDA-MB-231 cells in vitro: Comparison with gemcitabine

Gentian violet (GV), a cationic triphenylmethane dye, is used as an antifungal and antibacterial agent. Recently, attention has been focused on GV as a potential chemotherapeutic and antiangiogenic agent. The present study was undertaken to determine the suppressive effects of GV on human breast cancer MDA-MB-231 cells in vitro. The proliferation of MDA-MB-231 cells was suppressed by culture with GV (1-200 nM). The suppressive effects of GV on cell proliferation were not potentiated in the presence of various inhibitors that induce cell cycle arrest in vitro. This finding suggested that GV inhibits G1 and G2/M phase cell cycle arrest in MDA-MB-231 cells. The suppressive effects of GV on proliferation are mediated through the inhibition of various signaling pathways or nuclear transcription in vitro. Moreover, the suppressive effects of GV on cell proliferation were compared with that of gemcitabine, a strong antitumor agent that induces nuclear DNA damage. Notably, the culture with gemcitabine >50 nM suppressed cell proliferation, while the effects of GV were observed at >1 nM. The suppressive effects of gemcitabine on cell proliferation were not potentiated by GV. Overall, the present study demonstrated that GV exhibits a potential suppressive effect on the proliferation of human breast cancer MDA-MB-231 cells in vitro.

Integrinβ1 modulates tumour resistance to gemcitabine and serves as an independent prognostic factor in pancreatic adenocarcinomas

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies because of its broad resistance to chemotherapy. Numerous evidence indicates that integrinβ1 is upregulated in some human cancers, and it is correlated with resistance to various therapies. However, the role of integrinβ1 in chemotherapy is not clear in pancreatic cancer. The present study evaluates the potential of integrinβ1 to predict chemoresistance and prognosis in patients and to modulate resistance to gemcitabine in PDAC cells. Primary drug-resistance (DR) cancer cells were isolated, and DR cells from MiaPaCa-2 and AsPC-1 parent cell lines (PCL) were selected. Integrinβ1 expression was determined using immunohistochemistry (IHC), quantitative real-time PCR (qRT-PCR) and Western blotting. Changes in drug response after knockdown of integrinβ1 via RNA interference (RNAi) were evaluated using the viability of cancer cells as colon formation, proliferation using Western blot of Ki-67 and apoptosis using cleaved caspase-3 immunofluorescence. qRT-PCR and Western blot also detected variations in the activities of cdc42 and AKT after integrinβ1 suppression. Patient survival and relative factors were assessed using Kaplan-Meier and Cox regression analyses. Integrinβ1 expression was upregulated in PDAC, which was significantly associated with intrinsic and acquired gemcitabine resistance and worse outcomes. The downregulation of integrinβ1 attenuated PDAC chemoresistance, and this attenuation partially correlated with reduced Cdc42 and AKT activity, which are target molecules of integrinβ1 in some human cancers. These findings identified integrinβ1 as a special marker of drug resistance and a serious prognosis, and they furthermore support the use of integrinβ1 as a novel potential therapeutic target to overcome chemotherapy resistance. The results also suggest a possible drug-resistant signalling pathway of integrinβ1 in PDAC.

Increased regucalcin gene expression extends survival in breast cancer patients: Overexpression of regucalcin suppresses the proliferation and metastatic bone activity in MDA-MB-231 human breast cancer cells in vitro

Human breast cancer is highly metastatic to bone and drives bone turnover. Breast cancer metastases cause osteolytic lesions and skeletal damage that leads to bone fractures. Regucalcin, which plays a pivotal role as an inhibitor of signal transduction and transcription activity, has been suggested to act as a suppressor of human cancer. In the present study, we compared the clinical outcome between 44 breast cancer patients with higher regucalcin expression and 43 patients with lower regucalcin expression. Prolonged relapse-free survival was identified in the patients with increased regucalcin gene expression. We further demonstrated that overexpression of full length, but not alternatively spliced variants of regucalcin, induces G1 and G2/M phase cell cycle arrest, suppressing the proliferation of MDA-MB-231 cells, a commonly used in vitro model of human breast cancer that metastasize to bone causing osteolytic lesions. Overexpression of regucalcin was found to suppress multiple signaling pathways including Akt, MAP kinase and SAPK/JNK, and NF-κB p65 and β-catenin along with increased p53, a tumor suppressor, and decreased K-ras, c-fos and c-jun. Moreover, we found that co-culture of regucalcin-overexpressing MDA-MB-231 cells with mouse bone marrow cells prevented enhanced osteoclastogenesis and suppressed mineralization in mouse bone marrow cells in vitro. Taken together, the present study suggests that regucalcin may have important anticancer properties in human breast cancer patients. Mechanistically, these effects are likely mediated through suppression of multiple signaling pathways, upregulation of p53 and downregulation of oncogenes leading to anti-proliferative effects and reduced metastases to bone, a phenotype associated with poor clinical outcome.