The incidence of pancreatic adenocarcinoma is increasing with more than 43,000 predicted new cases in the US and 65,000 in Europe this year. Pancreatic cancer patients have a short life expectancy with less than 3–4% 5-y survival, which results in an equivalent incidence and mortality rate. One of the major challenges in pancreatic cancer is the identification of pharmacological approaches that overcome the resistance of this cancer to therapy. Intensive research in the past decades has led to the classification of pancreatic cancers and the identification of the driver key genetic events. Despite the advances in understanding the molecular mechanisms responsible for pancreatic cancer pathogenesis, this knowledge had little impact on significantly improving the treatment for this dismal disease. In particular, we know today that the lack of therapeutic response in pancreatic cancer is due to the intrinsic high resistance of these tumors to chemotherapy and radiation, rather than to the inappropriate design of these therapeutic approaches. Thus, in order to ensure a better outcome for pancreatic cancer patients, there is a strong need for research focused on the mechanism that determines this resistant phenotype and the means that might drive enhanced response to therapy.
NUPR1; pancreas cancer; hypoxia; glucose starvation; cannabinoids; AURKA
Pancreatic adenocarcinoma (PDAC) is a devastating disease with an extremely poor life expectancy and no effective treatment. Autophagy is a process of degradation of cytoplasmic component capable of recycling cellular components or eliminate specific targets. The presence of autophagy in PDAC has been demonstrated. However, the implicated cellular pathways are not fully understood and, more importantly, the role of autophagy in PDAC is matter of intensive debate. This review summarizes recently published data in an attempt to clarify the importance of autophagy in this disease and try to reconcile apparently contradictory results.
Arteries and veins modulate cardiovascular homeostasis and contribute to hypertension pathogenesis. Functional differences between arteries and veins are based upon differences in gene expression. To better characterize these expression patterns, and to identify candidate genes that could be manipulated selectively in the venous system, we performed whole genome expression profiling of arteries and veins.
We used the CodeLink platform and the major artery (thoracic aorta) and vein (caudal vena cava) of the rat.
The most prominent difference was pancreatitis associated protein (PAP1), expressed 64-fold higher in vena cava vs aorta. Expression of mRNA for thrombospondins (TSP-1, TSP-4) was greater than 5-fold higher in veins vs arteries. Higher mRNA expression of thrombospondins (TSP-1, 2, 4) and PAP1 in vena cava vs aorta was confirmed by PCR. Immunohistochemical analysis of tissue sections qualitatively confirmed a higher expression of these proteins in vena cava vs aorta.
This is the first gene array study of adult rat arterial and venous tissues, and also the first study to report differences in inflammatory genes between arteries and veins. Data from these studies may provide novel insights into the genetic basis for functional differences between arteries and veins in health and disease.
veins; arteries; gene expression; inflammation
Background and aims
PAP/HIP was first reported as an additional pancreatic secretory protein expressed during the acute phase of pancreatitis. It was shown in vitro to be anti‐apoptotic and anti‐inflammatory. This study aims to look at whether PAP/HIP plays the same role in vivo.
A model of caerulein‐induced pancreatitis was used to compare the outcome of pancreatitis in PAP/HIP−/− and wild‐type mice.
PAP/HIP−/− mice showed the normal phenotype at birth and normal postnatal development. Caerulein‐induced pancreatic necrosis was, however, less severe in PAP/HIP−/− mice than in wild‐type mice, as judged by lower amylasemia and lipasemia levels and smaller areas of necrosis. On the contrary, pancreas from PAP/HIP−/− mice was more sensitive to apoptosis, in agreement with the anti‐apoptotic effect of PAP/HIP in vitro. Surprisingly, pancreatic inflammation was more extensive in PAP/HIP−/− mice, as judged from histological parameters, increased myeloperoxidase activity and increased pro‐inflammatory cytokine expression. This result, in apparent contradiction with the limited necrosis observed in these mice, is, however, in agreement with the anti‐inflammatory function previously reported in vitro for PAP/HIP. This is supported by the observation that activation of the STAT3/SOCS3 pathway was strongly decreased in the pancreas of PAP/HIP−/− mice and by the reversion of the apoptotic and inflammatory phenotypes upon administration of recombinant PAP/HIP to PAP/HIP−/− mice.
The anti‐apoptotic and anti‐inflammatory functions described in vitro for PAP/HIP have physiological relevance in the pancreas in vivo during caerulein‐induced pancreatitis.
We hypothesized that inhibiting molecules that mediate the adaptation response to cellular stress can antagonize the resistance of pancreatic cancer cells to chemotherapeutic drugs. Toward this end, here, we investigated how VMP1, a stress-induced autophagy-associated protein, modulate stress responses triggered by chemotherapeutic agents in PDAC. We find that VMP1 is particularly overexpressed in poorly differentiated human pancreatic cancer. Pharmacological studies show that drugs that work, in part, via the endoplasmic reticulum stress response, induce VMP1 expression. Similarly, VMP1 is induced by known endoplasmic reticulum stress activators. Genetic inactivation of VMP1 using RNAi-based antagonize the pancreatic cancer stress response to antitumoral agents. Functionally, we find that VMP1 regulates both autophagy and chemotherapeutic resistance even in the presence of chloroquin, ATG5 or Beclin 1 siRNAs, or a Beclin 1-binding VMP1 mutant. In addition, VMP1 modulates endoplasmic reticulum stress independently of its coupling to the molecular and cellular autophagy machinery. Preclinical studies demonstrate that xenografts expressing an inducible and tractable form of VMP1 show increased resistance to the gemcitabine treatment. These results underscore a novel role for VMP1 as a potential therapeutic target for combinatorial therapies aimed at sensitizing pancreatic cancer cells to chemotherapeutic agents as well as provide novel molecular mechanisms to better understand this phenomenon.
Pancreatitis-associated protein (PAP) was discovered in the pancreatic juice of rats with acute pancreatitis. PAP is a 16 kDa secretory protein structurally related to the C-type lectins although classical lectin-related function has not been reported yet. Then, it was demonstrated that PAP expression may be activated in some tissues in a constitutive or injury- and inflammation-induced manner. More recently, it has been found that PAP acts as an anti-inflammatory factor in vitro and in vivo. PAP expression can be induced by several pro- and anti-inflammatory cytokines and by itself through a JAK/STAT3-dependent pathway. PAP is able to activate the expression of the anti-inflammatory factor SOCS3 through the JAK/STAT3-dependent pathway. The JAK/STAT3/SOCS3 pathway seems to be a common point between PAP and several cytokines. Therefore, it is reasonable to propose that PAP is a new anti-inflammatory cytokine.
Pancreatitis-associated protein; Pancreatitis; Janus kinases; STAT3; SOCS3; Anti-inflammatory; Lectin
AIM: To determine the effects of prophylactic peroxi-some proliferator-activated receptor (PPARγ) agonist administration in an experimental model of post-endoscopic retrograde cholangiopancreatography (post-ERCP) acute pancreatitis.
METHODS: Post-ERCP pancreatitis was induced in male Wistar rats by infusion of contrast medium into the pancreatic duct. In additional group, rosiglitazone, a PPARγ agonist, was administered 1 h before infusion of contrast medium. Plasma and pancreas samples were obtained 6 h after the infusion.
RESULTS: Infusion of contrast medium into the pan-creatic duct resulted in an inflammatory process characterized by increased lipase levels in plasma, and edema and myeloperoxidase activity (MPO) in pancreas. This result correlated with the activation of nuclear factor κB (NFκB) and the inducible NO synthase (iNOS) expression in pancreatic cells. Rosiglitazone reduced the increase in lipase and the level of edema and the increase in myeloperoxidase as well as the activation of NFκB and iNOS expression.
CONCLUSION: A single oral dose of rosiglitazone, given 1 h before post-ERCP pancreatitis induction is effective in reducing the severity of the subsequent inflammatory process. The protective effect of rosiglitazone was associated with NFκB inhibition and the blockage of leukocyte infiltration in pancreas.
Peroxisome proliferator-activated receptor γ; Pancreatitis; Endoscopic retrograde cholangio pancreatography; Inflammation; Nuclear factor κB
During the last couple decades, we have significantly advanced our understanding of mechanisms underlying the development of pancreatic ductural adenocarcinoma (PDAC). In the late 1990s into the early 2000s, a model of PDAC development and progression was developed as a multi-step process associated with the accumulation of somatic mutations. The correlation and association of these particular genetic aberrations with the establishment and progression of PDAC has revolutionized our understanding of this process. However, this model leaves out other molecular events involved in PDAC pathogenesis that contribute to its development and maintenance, specifically those being epigenetic events. Thus, a new model considering the new scientific paradigms of epigenetics will provide a more comprehensive and useful framework for understanding the pathophysiological mechanisms underlying this disease. Epigenetics is defined as the type of inheritance not based on a particular DNA sequence but rather traits that are passed to the next generation via DNA and histone modifications as well as microRNA-dependent mechanisms. Key tumor suppressors that are well established to play a role in PDAC may be altered through hypermethylation, and oncogenes can be upregulated secondary to permissive histone modifications. Factors involved in tumor invasiveness can be aberrantly expressed through dysregulated microRNAs. A noteworthy characteristic of epigenetic-based inheritance is its reversibility, which is in contrast to the stable nature of DNA sequence-based alterations. Given this nature of epigenetic alterations, it becomes imperative that our understanding of epigenetic-based events promoting and maintain PDAC continues to grow.
ArgBP2 (Arg-Binding Protein 2/SORBS2) is an adaptor protein involved in cytoskeleton associated signal transduction, thereby regulating cell migration and adhesion. These features are associated with its antitumoral role in pancreatic cancer cells. Tyrosine phosphorylation of ArgBP2, mediated by c-Abl kinase and counterbalanced by PTP-PEST phosphatase, regulates many of its interactions. However, the exact mechanisms of action and of regulation of ArgBP2 remain largely unknown. We found that ArgBP2 has the capacity to form oligomers which are destabilized by tyrosine phosphorylation. We could show that ArgBP2 oligomerization involves the binding of one of its SH3 domains to a specific proline rich cluster. ArgBP2 self-association increases its binding to some of its molecular partners and decreased its affinity for others. Hence, the phosphorylation/oligomerization state of ArgBP2 directly regulates its functions by modulating its adaptive capabilities. Importantly, using a human pancreatic cancer cell model (MiaPaCa-2 cells), we could validate that this property of ArgBP2 is critical for its cytoskeleton associated functions. In conclusions, we describe a new mechanism of regulation of ArgBP2 where tyrosine phosphorylation of the protein interfere with a SH3 mediated self-interaction, thereby controlling its panel of interacting partners and related functions.
The stress protein Nupr1 is a highly basic, multifunctional, intrinsically disordered protein (IDP). MSL1 is a histone acetyl transferase-associated protein, known to intervene in the dosage compensation complex (DCC). In this work, we show that both Nupr1 and MSL1 proteins were recruited and formed a complex into the nucleus in response to DNA-damage, which was essential for cell survival in reply to cisplatin damage. We studied the interaction of Nupr1 and MSL1, and their binding affinities to DNA by spectroscopic and biophysical methods. The MSL1 bound to Nupr1, with a moderate affinity (2.8 µM) in an entropically-driven process. MSL1 did not bind to non-damaged DNA, but it bound to chemically-damaged-DNA with a moderate affinity (1.2 µM) also in an entropically-driven process. The Nupr1 protein bound to chemically-damaged-DNA with a slightly larger affinity (0.4 µM), but in an enthalpically-driven process. Nupr1 showed different interacting regions in the formed complexes with Nupr1 or DNA; however, they were always disordered (“fuzzy”), as shown by NMR. These results underline a stochastic description of the functionality of the Nupr1 and its other interacting partners.
Tumor Protein 53-Induced Nuclear Protein 1 (TP53INP1) plays an important role during cell stress response in synergy with the potent “genome-keeper” p53. In human, the gene encoding TP53INP1 is expressed at very high level in some pathological situations, such as inflammation and prostate cancer (PC). TP53INP1 overexpression in PC seems to be a worse prognostic factor, particularly predictive of biological cancer relapse, making TP53INP1 a relevant specific target for molecular therapy of Castration Resistant (CR) PC. In that context, detection of TP53INP1 in patient biological fluids is a promising diagnostic avenue. We report here successful development of a new Enzyme-Linked Immunosorbent Assay (ELISA) detecting TP53INP1, taking advantage of molecular tools (monoclonal antibodies (mAbs) and recombinant proteins) generated in the laboratory during the course of basic functional investigations devoted to TP53INP1. The ELISA principle is based on a sandwich immunoenzymatic system, TP53INP1 protein being trapped by a first specific mAb coated on microplate then recognized by a second specific mAb. This new assay allows specific detection of TP53INP1 in serum of several PC patients. This breakthrough paves the way towards investigation of a large cohort of patients and assessment of clinical applications of TP53INP1 dosage.
•TP53INP1 is a key stress-response protein over-expressed in prostate cancer.•We have developed a new ELISA detecting TP53INP1 in serum of prostate cancer patients.•This ELISA will be a powerful tool in investigating value of TP53INP1 as a new biomarker in diagnostic and therapy.
ELISA; p53; TP53INP1; Prostate cancer; Biomarker; aa, amino acid; CR PC, castration resistant prostate cancer; ELISA, enzyme-linked immunosorbent assay; HRP, horse radish peroxydase; SFM, serum free medium; TP53INP1, tumor protein 53-induced nuclear protein 1
To assess the possibility of hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP) as a biological marker for detecting Bladder cancer (BCa), we examined the expression of HIP/PAP in both BCa specimens and BCa cell lines and measured HIP/PAP levels in urine from patients with BCa.
HIP/PAP expression in BCa samples was evaluated by western blot analysis, and urinary levels of HIP/PAP in patients with BCa were measured by enzyme-linked immunosorbent assay. Urine samples were collected from 10 healthy volunteers and 109 with benign urological disorders as controls, and from 101 patients who were diagnosed with BCa.
HIP/PAP was highly expressed in BCa samples as compared with control bladder. Urinary HIP/PAP concentrations were significantly higher in BCa patients than in controls (median value; 3.184 pg/mL vs. 55.200 pg/mL, P <0.0001, by Mann–Whitney U test). Urinary HIP/PAP levels in BCa patients correlated positively with pathological T stages and progression-risk groups among non-muscle invasive BCa (P = 0.0008, by Kruskal-Wallis test). Regarding the recurrence-risk classifications of non-muscle invasive BCa, the urinary levels of HIP/PAP were significantly higher in the intermediate than in the low risk group (P = 0.0002, by Mann–Whitney U test). Based on a cut-off of 8.5 pg/mL, the ability of urinary HIP/PAP levels to detect BCa had a sensitivity of 80.2%, specificity of 78.2%, positive predictive value (PPV) of 75.7%, and negative predictive value (NPV) of 82.3%.
HIP/PAP was abundantly expressed in BCa, and the urinary levels of HIP/PAP could be a novel and potent biomarker for detection of BCa, and also for predicting the risks of recurrence- and progression-risk of non-muscle invasive BCa. A large scale study will be needed to establish the usefulness of this biomarker.
Bladder cancer; Urinary marker; HIP/PAP; ELISA; ROC
Pancreatic adenocarcinoma (PDAC) is an extremely deadly disease for which all treatments available have failed to improve life expectancy significantly. This may be explained by the high metastatic potential of PDAC cells, which results from their dedifferentiation towards a mesenchymal phenotype. Some PDAC present cell-in-cell structures whose origin and significance are currently unknown. We show here that cell-in-cells form after homotypic cell cannibalism (HoCC). We found PDAC patients whose tumours display HoCC develop less metastasis than those without. In vitro, HoCC was promoted by inactivation of the nuclear protein 1 (Nupr1), and was enhanced by treatment with transforming growth factor β. HoCC ends with death of PDAC cells, consistent with a metastasis suppressor role for this phenomenon. Hence, our data indicates a protective role for HoCC in PDAC and identifies Nupr1 as a molecular regulator of this process.
cell cannibalism; metastasis; Nupr1; pancreatic cancer; TGFβ
Stress proteins of the pancreas, such as tumor protein 53-induced nuclear protein 1 (TP53INP1), are important factors in the invasion and metastasis of pancreatic cancer. TP53INP1 is a pro-apoptotic factor and is transcriptionally regulated in p53-dependent and -independent manners. A previous study proved that gemcitabine induces TP53INP1 expression in pancreatic cancer cells and the pancreatic cancer cell line (PANC-1). The present study aimed to clarify the association between TP53INP1 and gemcitabine sensitivity. The expression of TP53INP1 and its related factors, such as cell growth and cell cycle status in TP53INP1-knockout mouse embryonic fibroblasts [TP53INP1−/−-mouse embryonic fibroblasts (MEFs)] to those in wild-type counterparts (TP53INP1+/+-MEFs) were compared. Flow cytometric analysis demonstrated no difference of the checkpoint function in TP53INP1−/−-MEFs and TP53INP1+/+-MEFs when exposed to 10 ng/ml of gemcitabine. No significant difference was found in the level of p53 expression in the cell types, although the base level and gemcitabine-induced expression of p21 were significantly decreased in TP53INP1−/−-MEFs, compared to those in wild-type counterparts. Results showed that gemcitabine induced the p21 expression in TP53INP1+/+-MEFs, although not in TP53INP1−/−-MEFs. However, their respective cell-cycle checkpoints were not different. Therefore, TP53INP1 was found to be associated with drug sensitivity through control of the cell cycle.
gemcitabine; tumor protein 53-induced nuclear protein 1; p21; p53; cell cycle
Background: KLF16 is the least characterized family member of recently described metabolic regulators.
Results: We extensively characterize mechanisms of DNA binding and chromatin coupling used by KLF16 to regulate metabolic gene expression.
Conclusion: KLF16 is a novel regulator of metabolic genes by regulatable coupling to Sin3-histone deacetylase complexes.
Significance: This knowledge reveals key mechanisms used by KLF16 as a regulator of metabolic gene expression.
Krüppel-like factor (KLF) proteins have elicited significant attention due to their emerging key role in metabolic and endocrine diseases. Here, we extend this knowledge through the biochemical characterization of KLF16, unveiling novel mechanisms regulating expression of genes involved in reproductive endocrinology. We found that KLF16 selectively binds three distinct KLF-binding sites (GC, CA, and BTE boxes). KLF16 also regulated the expression of several genes essential for metabolic and endocrine processes in sex steroid-sensitive uterine cells. Mechanistically, we determined that KLF16 possesses an activation domain that couples to histone acetyltransferase-mediated pathways, as well as a repression domain that interacts with the histone deacetylase chromatin-remodeling system via all three Sin3 isoforms, suggesting a higher level of plasticity in chromatin cofactor selection. Molecular modeling combined with molecular dynamic simulations of the Sin3a-KLF16 complex revealed important insights into how this interaction occurs at an atomic resolution level, predicting that phosphorylation of Tyr-10 may modulate KLF16 function. Phosphorylation of KLF16 was confirmed by in vivo
32P incorporation and controlled by a Y10F site-directed mutant. Inhibition of Src-type tyrosine kinase signaling as well as the nonphosphorylatable Y10F mutation disrupted KLF16-mediated gene silencing, demonstrating that its function is regulatable rather than constitutive. Subcellular localization studies revealed that signal-induced nuclear translocation and euchromatic compartmentalization constitute an additional mechanism for regulating KLF16 function. Thus, this study lends insights on key biochemical mechanisms for regulating KLF sites involved in reproductive biology. These data also contribute to the new functional information that is applicable to understanding KLF16 and other highly related KLF proteins.
Endocrinology; Gene Silencing; Kruppel-like Factor (KLF); Metabolism; Sp1; Sin3
Pancreatic ductal adenocarcinoma remains one of the most lethal of all solid tumors with an overall five-year survival rate of only 3–5%. Its aggressive biology and resistance to conventional and targeted therapeutic agents lead to a typical clinical presentation of incurable disease once diagnosed. The disease is characterized by the presence of a dense stroma of fibroblasts and inflammatory cells, termed desmoplasia, which limits the oxygen diffusion in the organ, creating a strong hypoxic environment within the tumor. In this review, we argue that hypoxia is responsible for the highly aggressive and metastatic characteristics of this tumor and drives pancreatic cancer cells to oncogenic and metabolic changes facilitating their proliferation. However, the molecular changes leading to metabolic adaptations of pancreatic cancer cells remain unclear. Cachexia is a hallmark of this disease and illustrates that this cancer is a real metabolic disease. Hence, this tumor must harbor metabolic pathways which are probably tied in a complex inter-organ dialog during the development of this cancer. Such a hypothesis would better explain how under fuel source limitation, pancreatic cancer cells are maintained, show a growth advantage, and develop metastasis.
pancreatic cancer; hypoxia; metabolism; cachexia
Inactivation of the Transforming Growth Factor Beta (TGFβ) tumor suppressor pathway contributes to the progression of Pancreatic Ductal AdenoCarcinoma (PDAC) since it is inactivated in virtually all cases of this malignancy. Genetic lesions inactivating this pathway contribute to pancreatic tumor progression in mouse models. Transcriptional Intermediary Factor 1 gamma (TIF1γ) has recently been proposed to be involved in TGFβ signaling, functioning as either a positive or negative regulator of the pathway. Here, we addressed the role of TIF1γ in pancreatic carcinogenesis. Using conditional Tif1γ knockout mice (Tif1γlox/lox), we selectively abrogated Tif1γ expression in the pancreas of Pdx1-Cre;Tif1γlox/lox mice. We also generated Pdx1-Cre;LSL-KrasG12D;Tif1γlox/lox mice to address the effect of Tif1γ loss-of-function in precancerous lesions induced by oncogenic KrasG12D. Finally, we analyzed TIF1γ expression in human pancreatic tumors. In our mouse model, we showed that Tif1γ was dispensable for normal pancreatic development but cooperated with Kras activation to induce pancreatic tumors reminiscent of human Intraductal Papillary Mucinous Neoplasms (IPMNs). Interestingly, these cystic lesions resemble those observed in Pdx1-Cre;LSL-KrasG12D;Smad4lox/lox mice described by others. However, distinctive characteristics, such as the systematic presence of endocrine pseudo-islets within the papillary projections, suggest that SMAD4 and TIF1γ don't have strictly redundant functions. Finally, we report that TIF1γ expression is markedly down-regulated in human pancreatic tumors by quantitative RT–PCR and immunohistochemistry supporting the relevance of these findings to human malignancy. This study suggests that TIF1γ is critical for tumor suppression in the pancreas, brings new insight into the genetics of pancreatic cancer, and constitutes a promising model to decipher the respective roles of SMAD4 and TIF1γ in the multifaceted functions of TGFβ in carcinogenesis and development.
Inactivation of the TGFβ tumor suppressor pathway contributes to the progression of Pancreatic Ductal AdenoCarcinoma (PDAC), a devastating malignancy. Transcriptional Intermediary Factor 1γ (TIF1γ) has recently been proposed to be involved in TGFβ signaling, a pathway inactivated in virtually all cases of this malignancy. To address the role of TIF1γ in pancreatic carcinogenesis, we used conditional Tif1γ knockout mice. In a genetic background expressing a constitutively active mutation of KRAS oncogene (KrasG12D) recurrently found in patients with PDAC, Tif1γ inactivation induces pancreatic precancerous lesions resembling those observed in the absence of Smad4, a key player involved TGFβ signal transduction. This observation strengthens the notion that TIF1γ plays an active role in TGFβ signaling. Interestingly, we also found that TIF1γ expression was markedly down-regulated in human pancreatic tumors supporting the relevance of our findings to human malignancy. Characterization of new players involved in the outbreak of early pancreatic lesions that will eventually evolve into invasive pancreatic cancer is crucial to detect the disease earlier and eventually develop new therapeutic drugs.
Autophagy can promote cell survival or cell death, but the molecular basis underlying
its dual role in cancer remains obscure. Here we demonstrate that
Δ9-tetrahydrocannabinol (THC), the main active component of
marijuana, induces human glioma cell death through stimulation of autophagy. Our data
indicate that THC induced ceramide accumulation and eukaryotic translation initiation
factor 2α (eIF2α) phosphorylation and thereby activated an ER
stress response that promoted autophagy via tribbles homolog 3–dependent
(TRB3-dependent) inhibition of the Akt/mammalian target of rapamycin complex 1
(mTORC1) axis. We also showed that autophagy is upstream of apoptosis in
cannabinoid-induced human and mouse cancer cell death and that activation of this
pathway was necessary for the antitumor action of cannabinoids in vivo. These
findings describe a mechanism by which THC can promote the autophagic death of human
and mouse cancer cells and provide evidence that cannabinoid administration may be an
effective therapeutic strategy for targeting human cancers.
Cuprizone-induced demyelination is a mouse model of multiple sclerosis (MS) as cuprizone-fed mice exhibit neuroin-flammation and demyelination in the brain. Upon removal of cuprizone from the diet, inflammation is resolved and reparative remyelination occurs. In an Affymetrix Gene-Chip analysis, the stress-associated gene p8 was strongly upregulated (>10×) during cuprizone-induced demyelination but not remyelination. We verified this upregulation (>15×) of p8 in the CNS during demyelination by real-time polymerase chain reaction (PCR). This upregulation is brain-specific, as p8 is not elevated in the liver, lung, kidney, spleen, and heart of cuprizone-treated mice. We also localized the cellular source of p8 during cuprizone treatment, and further found elevated expression during embryogenesis but not in normal adult brain. Compared with wild-type controls, the death of oligodendrocytes in p8−/− mice is delayed, as is microglial recruitment to areas of demyelination. The corpus callosum of p8−/− mice demyelinates at a slower rate than wild-type mice, suggesting that p8 exacerbates CNS inflammation and demyelination. Enhanced expression of p8 is also observed in the spinal cords of mice with acute experimental autoimmune encephalomyelitis (EAE) induced by PLP139–151 peptide (10×). Increased expression is detected during disease onset and expression wanes during the remission phase. Finally, p8 is found upregulated (8×) in post-mortem tissue from MS patients and is higher in the plaque tissue compared with adjacent normal-appearing white and gray matter. Thus, p8 is an excellent candidate as a novel biomarker of demyelination.
glia; multiple sclerosis; cuprizone; biomarker; EAE
In cancer, cellular transformation is followed by tumour development. Knowledge on the mechanisms of transformation, involving activation of proto-oncogenes and inactivation of tumour-suppressor genes has considerably improved whereas tumour development remains poorly understood. An interesting way of gaining information on tumour progression mechanisms would be to identify genes whose expression is altered during tumour formation. We used the Affymetrix-based DNA microarray technology to analyze gene expression profiles of tumours derived from rasV12/E1A-transformed mouse embryo fibroblasts in order to identify the genes that could be involved in tumour development.
Among the 12,000 genes analyzed in this study, only 489 showed altered expression during tumour development, 213 being up-regulated and 276 down-regulated. The genes differentially expressed are involved in a variety of cellular functions, including control of transcription, regulation of mRNA maturation and processing, regulation of protein translation, activation of interferon-induced genes, intracellular signalling, apoptosis, cell growth, angiogenesis, cytoskeleton, cell-to-cell interaction, extracellular matrix formation, metabolism and production of secretory factors.
Some of the genes identified in this work, whose expression is altered upon rasV12/E1A transformation of MEFs, could be new cancer therapeutic targets.
ras; E1A; MEF; microarray; gene expression; tumour development.
p8 is a stress-induced protein with multiple functions and biochemically related to the architectural factor HMG-I/Y. We analyzed the expression and function of p8 in pancreatic cancer-derived cells.
Expression of p8 was silenced in the human pancreatic cancer cell lines Panc-1 and BxPc-3 by infection with a retrovirus expressing p8 RNA in the antisense orientation. Cell growth was measured in control and p8-silenced cells. Influence on p8 expression of the induction of intracellular pathways promoting cellular growth or growth arrest was monitored.
p8-silenced cells grew more rapidly than control cells transfected with the empty retrovirus. Activation of the Ras→Raf→MEK→ERK and JNK intracellular pathways down-regulated p8 expression. In addition, the MEK1/2 inhibitor U0126 and the JNK inhibitor SP600125 up-regulates expression of p8. Conversely, p38 or TGFβ-1 induced p8 expression whereas the specific p38 inhibitor SB203580 down-regulated p8 expression. Finally, TGFβ-1 induction was in part mediated through p38.
p8 inhibits the growth of human pancreatic cancer cells. p8 expression is induced through pathways involved in growth inhibition and repressed by factors that promote cell growth. These results suggest that p8 belongs to a pathway regulating the growth of pancreatic cancer cells.
p8; pancreatic cancer; ras; TGFβ-1; p38; JNK.