Targeting REG3ß limits pancreatic ductal adenocarcinoma progression through CTGF downregulation.

The crosstalk between the transformed tumoral cells and their microenvironment is a key aspect for pancreatic ductal adenocarcinoma (PDAC) progression. This molecular dialog is intensively studied because it may result in an efficient therapeutic target. Contrary to this near microenvironment, the stromal portion in direct contact with the transformed cells, a far microenvironment, placed at the periphery of the tumor mass, produces factors signaling tumors. Among these factors, REG3ß, produced by this part of the pancreas, is an important factor in promoting tumor progression. This paper demonstrated that targeting REG3ß protein with specific antibodies limits the PDAC tumor growth in an orthotopic, syngeneic mice model induced by injection of Panc02 cells. Then, we showed that CTGF is over-expressed in response to REG3ß in PDAC-derived cells. Moreover, inactivation of REG3ß by treating tumors with anti-REG3ß antibodies results in a strong decrease of CTGF in PDAC tumors. Lastly, we demonstrated that forced expression of CTGF in xenografted Panc02 cells abolishes the therapeutic effect of the anti-REG3ß antibody treatment. Altogether, these results indicate that the effect of REG3ß in promoting PDAC progression is mediated by CTGF over-activation. Thus, REG3ß is a promising therapeutic target to treat PDAC with an original rationale. In conclusion, we demonstrated that the far microenvironment is essential for PDAC progression by producing active secretory factors, and some of them could be used as therapeutic targets.

Transcriptome of 17ß-hydroxysteroid dehydrogenase type 2 plays both hormone-dependent and hormone-independent roles in MCF-7 breast cancer cells.

Breast cancer is a major cause of cancer-related death for women in western countries. 17ß-Hydroxysteroid dehydrogenases (17ß-HSDs) play important roles in the last step of sex-hormone activation and the first step of sex-hormone inactivation. 17ß-HSD2 is responsible for oxidizing the sex hormones. We used microarray technology to analyze the effect of 17ß-HSD2 on the MCF-7 cell transcript profile after knocking down 17ß-HSD2. Five hundred forty-two genes were regulated 1.5-fold or higher after treatment with 17ß-HSD2 siRNA. Knocking down 17ß-HSD2 interrupted nucleosome assembly. Pathway-Act-Network analysis showed that the MAPK and apoptosis signaling pathways were most regulated. In the gene-gene interaction network analysis, UGT2B15, which is involved in hormone metabolism, was the most regulated core gene. FOS, GREB1, and CXCL12 were the most regulated genes, and CXCL12 was related to tumor migration. Following 17ß-HSD2 knock-down, the cell viability decreased to 75.9%. The S-phase percentage decreased by 19.4%, the Q2-phase percentage in cell apoptosis testing increased by 1.5 times, and cell migration decreased to 66.0%. These results were consistent with our gene chip analysis and indicated that 17ß-HSD2 plays both hormone-dependent and hormone-independent enzymatic roles. In-depth investigations of this enzyme on the genomic level will help clarify its related molecular mechanisms.

Identification of the principal transcriptional regulators for low-fat and high-fat meal responsive genes in small intestine.

BACKGROUND: High-fat (HF) diet is a well-known cause of obesity. To identify principle transcriptional regulators that could be therapeutic targets of obesity, we investigated transcriptomic modulation in the duodenal mucosa following low-fat (LF) and HF meal ingestion. METHODS: Whereas one group of mice was sacrificed after fasting, the others were fed ad libitum with LF or HF meal, and sacrificed 30 min, 1 h and 3 h after the beginning of the meal. A transcriptome analysis of the duodenal mucosa of the 7 groups was conducted using both microarray and serial analysis of gene expression (SAGE) method followed by an Ingenuity Pathways Analysis (IPA). RESULTS: SAGE and microarray showed that the modulation of a total of 896 transcripts in the duodenal mucosa after LF and/or HF meal, compared to the fasting condition. The IPA identified lipid metabolism, molecular transport, and small molecule biochemistry as top three molecular and cellular functions for the HF-responsive, HF-specific, HF-delay, and LF-HF different genes. Moreover, the top transcriptional regulator for the HF-responsive and HF-specific genes was peroxisome proliferator-activated receptor alpha (PPARα). On the other hand, the LF-responsive and LF-specific genes were related to carbohydrate metabolism, cellular function and maintenance, and cell death/cellular growth and proliferation, and the top transcriptional regulators were forkhead box protein O1 (FOXO1) and cAMP response element binding protein 1 (CREB1), respectively. CONCLUSIONS: These results will help to understand the molecular mechanisms of intestinal response after LF and HF ingestions, and contribute to identify therapeutic targets for obesity and obesity-related diseases.

Estradiol-independent modulation of breast cancer transcript profile by 17beta-hydroxysteroid dehydrogenase type 1.

17beta-hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is a steroidal enzyme which, in breast cancer cells, mainly synthesizes 17-beta-estradiol (E2), an estrogenic hormone that stimulates breast cancer cell growth. We previously showed that the enzyme increased breast cancer cell proliferation via a dual effect on E2 and 5α-dihydrotestosterone (DHT) levels and impacted gene expression and protein profile of breast cancer cells cultured in E2-contained medium. Here, we used RNA interference technique combined with microarray analyses to investigate the effect of 17ß-HSD1 expression on breast cancer cell transcript profile in steroid-deprived condition. Our data revealed that knockdown of 17ß-HSD1 gene, HSD17B1, modulates the transcript profile of the hormone-dependent breast cancer cell line T47D, with 105 genes regulated 1.5 fold or higher (p < 0.05) in estradiol-independent manner. Using Ingenuity Pathway Analysis (IPA), we additionally assessed functional enrichment analyses, including biological functions and canonical pathways, and found that, in concordance with the role of 17ß-HSD1 in cancer cell growth, most regulated genes are cancer-related genes. Genes that primarily involved in the cell cycle progression, such as the cyclin A2 gene, CCNA2, are generally down-regulated whereas genes involved in apoptosis and cell death, including the pro-apoptotic gene XAF1, IFIH1 and FGF12, are on the contrary up-regulated by 17ß-HSD1 knockdown, and 21% of the modulated genes belong to this latter functional category. This indicates that 17ß-HSD1 may be involved in oncogenesis by favoring anti-apoptosis pathway in breast cancer cells and correborates with its previously shown role in increasing breast cancer cell proliferation. The gene regulation occurring in steroid-deprived conditions showed that 17ß-HSD1 can modulate endogenous gene expression in steroid-independent manners. Besides, we tested the ability of estrogen to induce or repress endogenous genes of T47D by microarray analysis. Expression of a total of 130 genes were found to increase or decrease 1.5-fold or higher (p < 0.05) in response to E2 treatment (1 nM for 48 h), revealing a list of potential new estrogen-responsive genes and providing useful information for further studies of estrogen-dependent breast cancer mechanisms. In conclusion, in breast cancer cells, in addition to its implication in the E2-dependent gene transcription, the present study demonstrates that 17ß-HSD1 also modulates gene expression via mechanisms independent of steroid actions. Those mechanisms that may include the ligand-independent gene transcription of estrogen receptor alpha (ERα), whose expression is positively correlated with that of the enzyme, and that may implicate 17ß-HSD1 in anti-apoptosis pathways, have been discussed.

Genomic data on breast cancer transcript profile modulation by 17beta-hydroxysteroid dehydrogenase type 1 and 17-beta-estradiol.

The data presented here are related to the research article entitled "Estradiol-independent modulation of breast cancer transcript profile by 17beta-hydroxysteroid dehydrogenase type 1" (J.A. Aka, E.L. Calvo, S.X. Lin, 2016) [1]. We evaluated the effect of the steroidal enzyme 17ß-HSD1 and its product, the estrogenic hormone 17-beta-estradiol (E2), on gene transcription profile of breast cancer cells. RNA interference technique was used to knock down the 17ß-HSD1 gene (HSD17B1) in the hormone-dependent breast cancer cell line T47D in steroid-deprived medium. Transfected cells were subsequently treated with E2, and microarray analyses (with three contrasts) were used to investigate (i) the effect of 17ß-HSD1 expression on breast cancer cell transcript profile in steroid-deprived condition, (ii) the effect of E2 on breast cancer gene expression and (iii) if E2 affects gene regulation by 17ß-HSD1. Functional enrichments of the differentially expressed genes were assessed using Ingenuity Pathway Analysis (IPA). Here, we showed data on 140 genes that are induced or repressed 1.5 time or higher (p < 0.05) in the HSD17B1-silenced and E2-treated T47D cells revealed by microarray analysis, and presented the 14 functional terms found in the cancer and in the cell death and survival categories revealed by the IPA biological function analysis. Data on IPA Canonical Pathway and network analyses is also presented. Further discussion on gene regulation by 17ß-HSD1 and E2 is provided in the accompanying publication [1].

Germline copy number variation in the YTHDC2 gene: does it have a role in finding a novel potential molecular target involved in pancreatic adenocarcinoma susceptibility?

OBJECTIVE: The vast majority of pancreatic cancers occurs sporadically. The discovery of frequent variations in germline gene copy number can significantly influence the expression levels of genes that predispose to pancreatic adenocarcinoma. We prospectively investigated whether patients with sporadic pancreatic adenocarcinoma share specific gene copy number variations (CNVs) in their germline DNA. PATIENTS AND METHODS: DNA samples were analyzed from peripheral leukocytes from 72 patients with a diagnosis of sporadic pancreatic adenocarcinoma and from 60 controls using Affymetrix 500K array set. Multiplex ligation-dependent probe amplification (MLPA) assay was performed using a set of self-designed MLPA probes specific for seven target sequences. RESULTS: We identified a CNV-containing DNA region associated with pancreatic cancer risk. This region shows a deletion of 1 allele in 36 of the 72 analyzed patients but in none of the controls. This region is of particular interest since it contains the YTHDC2 gene encoding for a putative DNA/RNA helicase, such protein being frequently involved in cancer susceptibility. Interestingly, 82.6% of Sicilian patients showed germline loss of one allele. CONCLUSIONS: Our results suggest that the YTHDC2 gene could be a potential candidate for pancreatic cancer susceptibility and a useful marker for early detection as well as for the development of possible new therapeutic strategies.

Analysis of germline gene copy number variants of patients with sporadic pancreatic adenocarcinoma reveals specific variations.

OBJECTIVES: The rapid fatality of pancreatic cancer is, in large part, the result of diagnosis at an advanced stage in the majority of patients. Identification of individuals at risk of developing pancreatic adenocarcinoma would be useful to improve the prognosis of this disease. There is presently no biological or genetic indicator allowing the detection of patients at risk. Our main goal was to identify copy number variants (CNVs) common to all patients with sporadic pancreatic cancer. METHODS: We analyzed gene CNVs in leukocyte DNA from 31 patients with sporadic pancreatic adenocarcinoma and from 93 matched controls. Genotyping was performed with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix). RESULTS: We identified 431 single nucleotide polymorphism (SNP) probes with abnormal hybridization signal present in the DNA of all 31 patients. Of these SNP probes, 284 corresponded to 3 or more copies and 147 corresponded to 1 or 0 copies. Several cancer-associated genes were amplified in all patients. Conversely, several genes supposed to oppose cancer development were present as single copy. CONCLUSIONS: These data suggest that a set of 431 CNVs could be associated with the disease. This set could be useful for early diagnosis.

Nuclear protein 1 promotes pancreatic cancer development and protects cells from stress by inhibiting apoptosis.

Pancreatic ductal adenocarcinoma (PDAC) has the lowest survival rate of all cancers and shows remarkable resistance to cell stress. Nuclear protein 1 (Nupr1), which mediates stress response in the pancreas, is frequently upregulated in pancreatic cancer. Here, we report that Nupr1 plays an essential role in pancreatic tumorigenesis. In a mouse model of pancreatic cancer with constitutively expressed oncogenic Kras(G12D), we found that loss of Nupr1 protected from the development of pancreatic intraepithelial neoplasias (PanINs). Further, in cultured pancreatic cells, nutrient deprivation activated Nupr1 expression, which we found to be required for cell survival. We found that Nupr1 protected cells from stress-induced death by inhibiting apoptosis through a pathway dependent on transcription factor RelB and immediate early response 3 (IER3). NUPR1, RELB, and IER3 proteins were coexpressed in mouse PanINs from Kras(G12D)-expressing pancreas. Moreover, pancreas-specific deletion of Relb in a Kras(G12D) background resulted in delayed in PanIN development associated with a lack of IER3 expression. Thus, efficient PanIN formation was dependent on the expression of Nupr1 and Relb, with likely involvement of IER3. Finally, in patients with PDAC, expression of NUPR1, RELB, and IER3 was significantly correlated with a poor prognosis. Cumulatively, these results reveal a NUPR1/RELB/IER3 stress-related pathway that is required for oncogenic Kras(G12D)-dependent transformation of the pancreas.

Identification of genomic alterations associated with the aggressiveness of pancreatic cancer using an ultra-high-resolution CGH array.

BACKGROUND: Genomic alterations present in pancreatic adenocarcinoma have been described only partially. In addition, the relations between these alterations and the aggressiveness of the phenotype remain unknown. METHODS: Genomic DNA and total RNA from 5 pancreatic cell lines, of which 2 have an aggressive phenotype and are gemcitabine-resistant (Mia-Paca2 and Panc-1), and 3 less aggressive and gemcitabine-sensitive (Capan-1, Capan-2 and BxPC3), have been purified. DNA abnormalities have been analyzed using an ultra-high-resolution CGH array and mRNA expression was studied with an Affymetrix GeneChip expression array. RESULTS: We identified 573 amplified and 30 deleted genes common to all 5 cell lines. Some of them have already been described, whereas other genes, implicated in signal transduction, apoptosis, cell cycle or cell migration, are described for the first time as being related to this cancer. Comparison of genomic abnormalities between the 2 most aggressive and the 3 less aggressive cell lines led to the identification of 368 genes specifically amplified in the aggressive cell lines. However, no specific gene deletion seems to be associated with the aggressive phenotype. CONCLUSION: Using a high-resolution approach, we could precisely describe the genomic alterations associated with pancreatic adenocarcinoma and determine those associated with an aggressive phenotype.

The WSB1 gene is involved in pancreatic cancer progression.

BACKGROUND: Pancreatic cancer cells generate metastases because they can survive the stress imposed by the new environment of the host tissue. To mimic this process, pancreatic cancer cells which are not stressed in standard culture conditions are injected into nude mice. Because they develop xenografts, they should have developed adequate stress response. Characterizing that response might provide new strategies to interfere with pancreatic cancer metastasis. METHODOLOGY/PRINCIPAL FINDINGS: In the human pancreatic cancer cell lines Panc-1, Mia-PaCa2, Capan-1, Capan-2 and BxPC3, we used Affymetrix DNA microarrays to compare the expressions of 22.000 genes in vitro and in the corresponding xenografts. We identified 228 genes overexpressed in xenografts and characterized the implication of one of them, WSB1, in the control of apoptosis and cell proliferation. WSB1 generates 3 alternatively spliced transcripts encoding distinct protein isoforms. In xenografts and in human pancreatic tumors, global expression of WSB1 mRNA is modestly increased whereas isoform 3 is strongly overexpressed and isoforms 1 and 2 are down-regulated. Treating Mia-PaCa2 cells with stress-inducing agents induced similar changes. Whereas retrovirus-forced expression of WSB1 isoforms 1 and 2 promoted cell growth and sensitized the cells to gemcitabine- and doxorubicin-induced apoptosis, WSB1 isoform 3 expression reduced cell proliferation and enhanced resistance to apoptosis, showing that stress-induced modulation of WSB1 alternative splicing increases resistance to apoptosis of pancreatic cancer cells. CONCLUSIONS/SIGNIFICANCE: Data on WSB1 regulation support the hypothesis that activation of stress-response mechanisms helps cancer cells establishing metastases and suggest relevance to cancer development of other genes overexpressed in xenografts.