Role In Pancreatic Cancer Tumorigenesis Research Articles

OTUB1/NDUFS2 axis promotes pancreatic tumorigenesis through protecting against mitochondrial cell death

Pancreatic cancer is one of the most fatal cancers in the world. A growing number of studies have begun to demonstrate that mitochondria play a key role in tumorigenesis. Our previous study reveals that NDUFS2 (NADH: ubiquinone oxidoreductase core subunit S2), a core subunit of the mitochondrial respiratory chain complex I, is upregulated in Pancreatic adenocarcinoma (PAAD). However, its role in the development of PAAD remains unknown. Here, we showed that NDUFS2 played a critical role in the survival, proliferation and migration of pancreatic cancer cells by inhibiting mitochondrial cell death. Additionally, protein mass spectrometry indicated that the NDUFS2 was interacted with a deubiquitinase, OTUB1. Overexpression of OTUB1 increased NDUFS2 expression at the protein level, while knockdown of OTUB1 restored the effects in vitro. Accordingly, overexpression and knockdown of OTUB1 phenocopied those of NDUFS2 in pancreatic cancer cells, respectively. Mechanically, NDUFS2 was deubiquitinated by OTUB1 via K48-linked polyubiquitin chains, resulted in an elevated protein stability of NDUFS2. Moreover, the growth of OTUB1-overexpressed pancreatic cancer xenograft tumor was promoted in vivo, while the OTUB1-silenced pancreatic cancer xenograft tumor was inhibited in vivo. In conclusion, we revealed that OTUB1 increased the stability of NDUFS2 in PAAD by deubiquitylation and this axis plays a pivotal role in pancreatic cancer tumorigenesis and development.

The role of amino acid metabolism alterations in pancreatic cancer: From mechanism to application.

The incidence of pancreatic cancer is increasing in both developed and developing Nations. In recent years, various research evidence suggested that reprogrammed metabolism may play a key role in pancreatic cancer tumorigenesis and development. Therefore, it has great potential as a diagnostic, prognostic and therapeutic target. Amino acid metabolism is deregulated in pancreatic cancer, and changes in amino acid metabolism can affect cancer cell status, systemic metabolism in malignant tumor patients and mistakenly involved in different biological processes including stemness, proliferation and growth, invasion and migration, redox state maintenance, autophagy, apoptosis and even tumor microenvironment interaction. Generally, the above effects are achieved through two pathways, energy metabolism and signal transduction. This review aims to highlight the current research progress on the abnormal alterations of amino acids metabolism in pancreatic cancer, how they affect tumorigenesis and development of pancreatic cancer and the application prospects of them as diagnostic, prognostic and therapeutic targets.

Insulin receptor tyrosine kinase substrate (IRTKS) promotes the tumorigenesis of pancreatic cancer via PI3K/AKT signaling.

Pancreatic cancer (PC) is a common type of tumor, which ranks for the seventh leading cause of cancer death worldwide. Insulin receptor tyrosine kinase substrate (IRTKS) plays an important regulatory role in cell proliferation, motility and survival. In this study, we explore the effect of IRTKS on the occurrence and development of PC. The expression and clinical features of IRTKS were predicted in database, PC cell lines and samples. IRTKS overexpressed and knocked down PC cell lines were established by lentivirus. CCK-8 assay, scratch migration assay and Transwell assay were used to analyze IRTKS oncogenic functions in cell lines. Bioinformatic enrichment analysis were conducted to explore the biological functions IRTKS involved in PC and Western Bolt assay was performed to reveal the downstream signaling molecules. It is detected that IRTKS is highly expressed in PC (P < 0.05), and overexpression of IRTKS predicted worse overall survival (OS, P = 0.018). The proliferation, migration and invasion ability were significantly enhanced in IRTKS overexpressed cells and inhibited in IRTKS knocked down cells (P < 0.05). Bioinformatic enrichment analysis based on GSE46583 dataset showed that IRTKS was significantly involved in PI3K/AKT pathway. Further investigation revealed that overexpression of IRTKS upregulated the ratio of p-PI3K/PI3K and p-AKT/AKT in vitro, while silencing of IRTKS presented opposite results, and PI3K inhibitor LY294002 treatment induced the phenotypic alteration of cell lines (P < 0.05). In conclusion, IRTKS plays an important role in PC tumorigenesis via PI3K/AKT pathway phosphorylated activation, and has a potential clinical application value in prognosis for PC.

Cancer stem cells markers associated with development and aggressive phenotype in pancreatic cancer

Background: Cancer stem cells, also known as tumor-initiating cells, are suggested to be responsible for drug resistance and cancer development due in part to their ability to self-renew themselves and differentiate into heterogeneous lineages of cancer cells. Objective: This study was designed to investigate the role of cancer stem cells in pancreatic cancer. Methods: A retrospective clinicopathological analysis was undertaken in 112 patients diagnosed with pancreatic ductal adenocarcinoma between 2005 and 2010, and immunohistochemistry was performed with antibodies against CD133, CD24, and OCT4. Positive nuclear, cytoplasmic or membrane staining for each antibody was rated on staining intensity, being classified into low/moderate or strong staining groups. Results were analyzed relative to each patient’s clinicopathological parameters. Results: There was an established relationship between the staining of the markers with some variables associated with worse prognosis, being the three markers present in most tumor cells and associated with tumor progression. We suppose that cancer stem cells are present from the beginning of tumor initiation and are intrinsically related to tumor development. Although the presence of stem cells has been associated with molecular biology of various tumors, their expression in pancreatic cancer has not yet been clinically reported. Conclusion: The presence of stem cells and their role in pancreatic cancer tumorigenesis may be considered as valuable prognostic factors, although the mechanism involved needs further investigation. Increasing insights into role of cancer stem cells and carcinogenesis can ultimately generate new ideas for molecularly based diagnostic and therapeutic approaches.

Abstract 1040: Characterization of extracellular vesicles in pancreatic cancer: Changing the way we think about tumorigenesis

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer-related deaths by 2030. Patients diagnosed with PDAC have a 5-year survival rate ~9%. Detection of pre-neoplastic lesions has the potential to improve treatment and overall survival in pancreatic cancer (PC) by 4-5 fold. However, there is currently no validated screening test for the non-invasive and accurate detection of early stage PC. Extracellular vesicles (EVs) arise from invagination of, and secretion from, cells of all tissue types. Their role in mediating PC tumorigenesis however, is just beginning to be studied. We have found that EVs derived from PC cells (cancer-derived EVs, CDEVs), can impart significant phenotypic and metabolic transformational effects on normal human pancreas cells (hTERT-HPNE and H6c7), tantamount to an epithelial-to-mesenchymal transition (EMT). The goal of this study was to characterize the biochemical cargo of EVs toward understanding their role in PC tumorigenesis. Results: We isolated CDEVs from various established and PDX PC cell lines. After validating enrichment of EV fractions with quantitative ELISA, immunoblot and transmission electron microscopy (TEM), we added CDEVs to culture media of normal cells. We found that CDEVs induce a myriad of changes in normal cells, including significant morphological changes, increased proliferation and an uncharacteristic invasive capability. CDEVs also caused a bioenergetic switch in normal cells, from a quiescent, aerobic profile to a highly energetic and glycolytic profile. Comparative analyses of CDEVs and normal-derived EVs (NDEVs) using 1H- and 13C-NMR showed significantly different biochemical fingerprints. Interestingly, we found that NDEVs contained more amino acids than CDEVs, while CDEVs contained elevated amounts of urea and lactic acid. We next designed a 13C-isotope labeling flux experiment to trace the fate of carbon metabolized from 13C-glucose fed to cells in culture. Using UHPLC/Q-ToF-MS, we identified several differentially labeled isotopes in CDEVs, particularly surrounding lipid biosynthesis and folate. Conclusions: Our results indicate that CDEVs confer enormous transformational properties to normal human pancreas cells in vitro. We hypothesize that EVs could impart tumorigenic properties to normal cells in vivo and this influence could unveil novel mechanisms underpinning cancer onset and progression. We show that there are robust biochemical differences between CDEVs and NDEVs. Biochemical characterization of EV cargo can uncover abrogated pathways in which signaling is mediated by EVs. These signals may be detectable before progression of PC to PDAC, leading to the development of assays for earlier diagnosis in patients. Citation Format: Charles P. Hinzman, Michael Girgis, Yaoxiang Li, Meth Jayatilake, Meena Rajagopal, Partha P. Banerjee, Amrita K. Cheema. Characterization of extracellular vesicles in pancreatic cancer: Changing the way we think about tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1040.

Knockdown of ISOC1 suppresses cell proliferation in pancreatic cancer in vitro.

Pancreatic cancer is a deadly disease that is frequently associated with mortality at the time of diagnosis due to rapid metastasis, which makes it unsuitable for operative surgery, and resistant to chemotherapy and radiation therapy. Isochorismatase domain-containing protein 1 (ISOC1) has putative isochorismatase activity, and is positively regulated by estrogen in human breast cancer. However, its role in pancreatic cancer has yet to be fully elucidated. Analysis from datasets downloaded from The Cancer Genome Atlas and Genotype-Tissue Expression databases indicated that the ISOC1 mRNA expression level was increased in pancreatic cancer tissues, compared with normal pancreatic tissues. In the present study, it was determined that the human pancreatic cancer cell lines SW 1990, PANC-1 and AsPC-1 had increased expression levels of ISOC1 mRNA, compared with human pancreatic ductal epithelial cells. Additionally, two of the pancreatic cancer cell lines, SW 1990 and PANC-1, transfected with lentivirus-delivered short hairpin RNA, to knockdown the expression of ISOC1, were established. Cell counting and MTT assays indicated that knockdown of ISOC1 decreased the ability of cell growth and proliferation in pancreatic cancer cells. Furthermore, Annexin V staining and caspase-3/7 activity assays demonstrated that inhibition of ISOC1 promoted cell apoptosis via elevation of the expression of caspase-3/7. Furthermore, inhibition of ISOC1 impaired the cell migration and invasive capability of the cells. In conclusion, ISOC1 exerts a role in pancreatic cancer cell growth and apoptosis, and may have a role in pancreatic cancer tumorigenesis.

Abstract A16: Mutant Kras associated protein oxidation in pancreatic neoplasia

Abstract Recent studies have suggested that mutant Kras associated activation of the Nrf2 pathway may have a significant role in pancreatic cancer tumorigenesis. Nrf2 regulates a battery of antioxidant genes, including peroxiredoxin-1 (Prdx-1), that are responsible for maintaining redox homeostasis in the cell. While ROS detoxification may have significant roles in cancer, several non-classical mechanisms of redox signaling associated with protein oxidation and phosphorylation are also important in tumorigenesis. Prdx-1 can regulate transcription as a cofactor in multiple oxidation states, represses tumorigenesis in its reduced state, and can act as a nuclear chaperone in elevated states of oxidation and when phosphorylated. We are therefore investigating the role of Prdx-1 and its oxidation states in oncogenic signaling pathways in mutant Kras models of pancreatic tumorigenesis and neoplasia. Our data demonstrate that Prdx1 is localized to the nucleus in normal c57-BL6 mice and exclusively located in the cytoplasm in normal pancreatic cells in the EL-Kras model of pancreatic neoplasia. Moreover, in acinar to ductal metaplatic pancreatic cells in EL-Kras mice, there is an increase in cytoplasmic Prdx1 expression and evidence of nuclear staining. Papillary cells in lesions of EL-Kras mice have apical Prdx-1 expression and ductal cells lining these lesions have higher cytoplasmic Prdx-1 expression and some nuclear Prdx-1 localization. This suggests that throughout tumor progression, Prdx-1 is differentially regulated. In vitro, neoplastic and tumorigenic pancreatic cell lines have more total Prdx-1 and oxidized Prdx-1 expression than non-tumorigenic cell lines. Moreover, cells that have mutant Kras were associated with higher levels of protein oxidation than those with wildtype Kras expression. Interestingly, mutant Kras was also associated with differences in pERK interaction with Prdx-1, which was also differentially regulated by fatty acids that control pancreatic neoplasia. In addition, ERK phosphorylation was also modified by fatty acid treatment in wildtype and mutant Kras normal, neoplastic, and tumorigenic cell lines. Our data therefore suggests that mutant Kras is associated with elevated levels of Prdx-1 oxidation and that Kras mediated activation of ERK could be associated with changes in Prdx-1 signaling in pancreatic neoplasia. Citation Format: Michelle A. Schultz, Rital Shah, Brian DeCant, David Bentrem, Paul Grippo. Mutant Kras associated protein oxidation in pancreatic neoplasia. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A16.

Flavonoid apigenin modified gene expression associated with inflammation and cancer and induced apoptosis in human pancreatic cancer cells through inhibition of GSK‐3β/NF‐κB signaling cascade

The objective was to examine the inhibitory effects of citrus fruit bioactive compounds on BxPC-3 and PANC-1 human pancreatic cancer cells, focusing on the antiproliferative mechanism of action of the flavonoid apigenin related to the glycogen synthase kinase-3β/nuclear factor kappa B signaling pathway. Flavonoids, limonoids, phenolic acids, and ascorbic acid were tested for cytotoxic effects on BxPC-3 and PANC-1 cells; apigenin was the most potent (IC50 = 23 and 12 μM for 24 and 48 h for BxPC-3 and IC50 = 71 and 41 μM for 24 and 48 h for PANC-1). Apigenin induced pancreatic cell death through inhibition of the glycogen synthase kinase-3β/nuclear factor kappa B signaling pathway. Apigenin arrested cell cycle at G2 /M phase (36 and 32% at 50 μM for BxPC-3 and PANC-1, respectively) with concomitant decrease in the expression of cyclin B1. Apigenin activated the mitochondrial pathway of apoptosis (44 and 14% at 50 μM for BxPC-3 and PANC-1, respectively) and modified the expression of apoptotic proteins. Apigenin highly upregulated the expression of cytokine genes IL17F (114.2-fold), LTA (33.1-fold), IL17C (23.2-fold), IL17A (11.3-fold), and IFNB1 (8.9-fold) in BxPC-3 cells, which potentially contributed to the anticancer properties. Flavonoids have a protective role in pancreatic cancer tumorigenesis.

Ectopic expression of VAV1 reveals an unexpected role in pancreatic cancer tumorigenesis

Herein, we show that the hematopoietic-specific GEF VAV1 is ectopically expressed in primary pancreatic adenocarcinomas due to demethylation of the gene promoter. Interestingly, VAV1-positive tumors had a worse survival rate compared to VAV1-negative tumors. Surprisingly, even in the presence of oncogenic KRAS, VAV1 RNAi abrogates neoplastic cellular proliferation in vitro and in vivo, thus identifying Vav1 as a growth-stimulatory protein in this disease. Vav1 acts synergistically with the EGF receptor to stimulate pancreatic tumor cell proliferation. Mechanistically, the effects of Vav1 require its GEF activity and the activation of Rac1, PAK1, and NF-κB and involve cyclin D1 upregulation. Thus, the discovery of prooncogenic pathways regulated by Vav1 makes it an attractive target for therapeutic intervention.