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Fulltext P53 expression in invasive pancreatic adenocarcinoma and precursor lesions

Norfadzilah MY, Pailoor J, Retneswari M, Chinna K, Noor LM

Malays J Pathol, 2011 Dec;33(2):89-94.
PMID: 22299208 MyJurnal

Patients with pancreatic adenocarcinoma are known to have a high mortality rate. The 5-year survival rate still remains low even now compared to that of the 1960's despite new advances in management including surgery, chemotherapy, pathological classification and molecular diagnostic technologies. Precursors to invasive pancreatic adenocarcinoma have been identified in the last ten years that include mucinous cystic neoplasm, intraductal papillary mucinous neoplasm and pancreatic intraepithelial neoplasia. p53 protein accumulation in the nuclei is a common molecular event in most human neoplasms. Our objective is to investigate p53 expression in pancreatic adenocarcinoma and precursor lesions and their significance. The selected study material encompassed 31 invasive ductal adenocarcinoma, 15 mucinous cystic neoplasm and papillary mucinous neoplasm, and 27 cases of pancreatic intraepithelial neoplasia including grade 1, 2 and 3. Immunoscore was given for each case based on intensity of staining and percentage of cells positive and compared between precursor lesions and invasive adenocarcinoma. A score of 50 and above was considered significant. The results showed that p53 expression increased progressively and significantly with the grade of pancreatic intraepithelial neoplasia and adenocarcinoma (p-value < 0.001). These findings support the concept of multistep carcinogenesis in pancreatic adenocarcinoma and suggest that p53 inactivation occurs in the progression of precursors to pancreatic adenocarcinoma.

Matched MeSH terms: Carcinoma, Pancreatic Ductal/metabolism*
Fulltext Smoking Modifies Pancreatic Cancer Risk Loci on 2q21.3

Mocci E, Kundu P, Wheeler W, Arslan AA, Beane-Freeman LE, Bracci PM, et al.

Cancer Res, 2021 Jun 01;81(11):3134-3143.
PMID: 33574088 DOI: 10.1158/0008-5472.CAN-20-3267

Germline variation and smoking are independently associated with pancreatic ductal adenocarcinoma (PDAC). We conducted genome-wide smoking interaction analysis of PDAC using genotype data from four previous genome-wide association studies in individuals of European ancestry (7,937 cases and 11,774 controls). Examination of expression quantitative trait loci data from the Genotype-Tissue Expression Project followed by colocalization analysis was conducted to determine whether there was support for common SNP(s) underlying the observed associations. Statistical tests were two sided and P < 5 × 10-8 was considered statistically significant. Genome-wide significant evidence of qualitative interaction was identified on chr2q21.3 in intron 5 of the transmembrane protein 163 (TMEM163) and upstream of the cyclin T2 (CCNT2). The most significant SNP using the Empirical Bayes method, in this region that included 45 significantly associated SNPs, was rs1818613 [per allele OR in never smokers 0.87, 95% confidence interval (CI), 0.82-0.93; former smokers 1.00, 95% CI, 0.91-1.07; current smokers 1.25, 95% CI 1.12-1.40, P interaction = 3.08 × 10-9). Examination of the Genotype-Tissue Expression Project data demonstrated an expression quantitative trait locus in this region for TMEM163 and CCNT2 in several tissue types. Colocalization analysis supported a shared SNP, rs842357, in high linkage disequilibrium with rs1818613 (r 2 = 0. 94) driving both the observed interaction and the expression quantitative trait loci signals. Future studies are needed to confirm and understand the differential biologic mechanisms by smoking status that contribute to our PDAC findings. SIGNIFICANCE: This large genome-wide interaction study identifies a susceptibility locus on 2q21.3 that significantly modified PDAC risk by smoking status, providing insight into smoking-associated PDAC, with implications for prevention.

Matched MeSH terms: Carcinoma, Pancreatic Ductal/metabolism
Fulltext Soluble factors from stellate cells induce pancreatic cancer cell proliferation via Nrf2-activated metabolic reprogramming and ROS detoxification

Wu YS, Looi CY, Subramaniam KS, Masamune A, Chung I

Oncotarget, 2016 Jun 14;7(24):36719-36732.
PMID: 27167341 DOI: 10.18632/oncotarget.9165

Pancreatic stellate cells (PSC), a prominent stromal cell, contribute to the progression of pancreatic ductal adenocarcinoma (PDAC). We aim to investigate the mechanisms by which PSC promote cell proliferation in PDAC cell lines, BxPC-3 and AsPC-1. PSC-conditioned media (PSC-CM) induced proliferation of these cells in a dose- and time-dependent manner. Nrf2 protein was upregulated and subsequently, its transcriptional activity was increased with greater DNA binding activity and transcription of target genes. Downregulation of Nrf2 led to suppression of PSC-CM activity in BxPC-3, but not in AsPC-1 cells. However, overexpression of Nrf2 alone resulted in increased cell proliferation in both cell lines, and treatment with PSC-CM further enhanced this effect. Activation of Nrf2 pathway resulted in upregulation of metabolic genes involved in pentose phosphate pathway, glutaminolysis and glutathione biosynthesis. Downregulation and inhibition of glucose-6-phosphate-dehydrogenase with siRNA and chemical approaches reduced PSC-mediated cell proliferation. Among the cytokines present in PSC-CM, stromal-derived factor-1 alpha (SDF-1α) and interleukin-6 (IL-6) activated Nrf2 pathway to induce cell proliferation in both cells, as shown with neutralization antibodies, recombinant proteins and signaling inhibitors. Taken together, SDF-1α and IL-6 secreted from PSC induced PDAC cell proliferation via Nrf2-activated metabolic reprogramming and ROS detoxification.

Matched MeSH terms: Carcinoma, Pancreatic Ductal/metabolism
Paracrine IL-6 signaling mediates the effects of pancreatic stellate cells on epithelial-mesenchymal transition via Stat3/Nrf2 pathway in pancreatic cancer cells

Wu YS, Chung I, Wong WF, Masamune A, Sim MS, Looi CY

Biochim Biophys Acta Gen Subj, 2017 Feb;1861(2):296-306.
PMID: 27750041 DOI: 10.1016/j.bbagen.2016.10.006

BACKGROUND: We previously showed that pancreatic stellate cells (PSC) secreted interleukin (IL)-6 and promoted pancreatic ductal adenocarcinoma (PDAC) cell proliferation via nuclear factor erythroid 2 (Nrf2)-mediated metabolic reprogramming. Epithelial-mesenchymal transition (EMT) is a key process for the metastatic cascade. To study the mechanism of PDAC progression to metastasis, we investigated the role of PSC-secreted IL-6 in activating EMT and the involvement of Nrf2 in this process.
METHODS: Gene expression of IL-6 and IL-6Rα in PSC and PDAC cells was measured with qRT-PCR. The role of PSC-secreted IL-6, JAK/Stat3 signaling, and Nrf2 mediation on EMT-related genes expression was also examined with qRT-PCR. EMT phenotypes were assessed with morphological change, wound healing, migration, and invasion.
RESULTS: PSC expressed higher mRNA levels of IL-6 but lower IL-6Rα compared to PDAC cells. Neutralizing IL-6 in PSC secretion reduced mesenchymal-like morphology, migration and invasion capacity, and mesenchymal-like gene expression of N-cadherin, vimentin, fibronectin, collagen I, Sip1, Snail, Slug, and Twist2. Inhibition of JAK/Stat3 signaling induced by IL-6 repressed EMT and Nrf2 gene expression. Induction of Nrf2 activity by tert-butylhydroquinone (tBHQ) increased both EMT phenotypes and gene expression (N-cadherin, fibronectin, Twist2, Snail, and Slug) repressed by IL-6 neutralizing antibody. Simultaneous inhibition of Nrf2 expression with siRNA and Stat3 signaling further repressed EMT gene expression, indicating that Stat3/Nrf2 pathway mediates EMT induced by IL-6.
CONCLUSIONS: IL-6 from PSC promotes EMT in PDAC cells via Stat3/Nrf2 pathway.
GENERAL SIGNIFICANCE: Targeting Stat3/Nrf2 pathway activated by PSC-secreted IL-6 may provide a novel therapeutic option to improve the prognosis of PDAC.

Matched MeSH terms: Carcinoma, Pancreatic Ductal/metabolism