The multidisciplinary management of gastrointestinal cancer. Pancreatic cancer: from pathogenesis to cure

Usp9x Promotes Survival in Human Pancreatic Cancer and Its Inhibition Suppresses Pancreatic Ductal Adenocarcinoma In Vivo Tumor Growth

Usp9x has emerged as a potential therapeutic target in some hematologic malignancies and a broad range of solid tumors including brain, breast, and prostate. To examine Usp9x tumorigenicity and consequence of Usp9x inhibition in human pancreatic tumor models, we carried out gain- and loss-of-function studies using established human pancreatic tumor cell lines (PANC1 and MIAPACA2) and four spontaneously immortalized human pancreatic patient-derived tumor (PDX) cell lines. The effect of Usp9x activity inhibition by small molecule deubiquitinase inhibitor G9 was assessed in 2D and 3D culture, and its efficacy was tested in human tumor xenografts. Overexpression of Usp9x increased 3D growth and invasion in PANC1 cells and up-regulated the expression of known Usp9x substrates Mcl-1 and ITCH. Usp9x inhibition by shRNA-knockdown or by G9 treatment reduced 3D colony formation in PANC1 and PDX cell lines, induced rapid apoptosis in MIAPACA2 cells, and associated with reduced Mcl-1 and ITCH protein levels. Although G9 treatment reduced human MIAPACA2 tumor burden in vivo, in mouse pancreatic cancer cell lines established from constitutive (8041) and doxycycline-inducible (4668) KrasG12D/Tp53R172H mouse pancreatic tumors, Usp9x inhibition increased and sustained the 3D colony growth and showed no significant effect on tumor growth in 8041-xenografts. Thus, Usp9x inhibition may be therapeutically active in human PDAC, but this activity was not predicted from studies of genetically engineered mouse pancreatic tumor models.

Bakkenolide A inhibits leukemia by regulation of HDAC3 and PI3K/Akt-related signaling pathways

Leukemia has been the third type of cancer killing many people across the world. Bakkenolide A (Bak), extracted from Petasites tricholobus, has been suggested to against cancer and display protective effects on inflammatory cytokines formation. And increasing evidences suggest that histone deacetylase 3 (HDAC3) plays vital roles in cancer formation and persistence via cell death, apoptosis and inflammation. But the function of Bakkenolide A in regulating leukemia is not understood yet, particularly via HDAC3. Here, we found that HDAC3 is up-regulated in clinical samples of leukemia compared with adjacent normal tissues. Then the expression of HDAC3 was knocked down via RNA interference in K562 cells. And inhibition of HDAC3 expression is able to improve leukemia invasion, migration and proliferation. Further, we also found HDAC3 bound to IκBα, affecting subsequent inflammation response. Moreover, Bakkenolide A was found to inhibit inflammation, induce apoptosis and cell death in leukemia cells via PI3K-regulated signaling pathway, down-regulating IKKs expression and suppressing in proinflammatory cytokines of IL-1β, IL-18 and TNF-α. Up-regulation of Caspase3/7 was observed in cells of HDAC3-knockdown and Bakkenolide A treatment, inducing leukemia cell apoptosis. Also, the expression of Akt and GSK were activated by HDAC3-knockdown and Bakkenolide A-treatment. Thus, these results indicated that Bakkenolide A-mediated HDAC3 sensitization in leukemia cells seem to be associated with activation of effector IKKs, Akt/GSK, and caspases through induction of the PI3K pathway, leading to inflammation, cell death, and apoptosis.

Histone deacetylase 3 promotes pancreatic cancer cell proliferation, invasion and increases drug-resistance through histone modification of P27, P53 and Bax

Pancreatic cancer is one of the most aggressive solid malignancies with a dismal survival rate. Recent studies have shown that high expression levels of histone deacetylase 3 (HDAC3) correlate with malignant phenotype. However, the expression patterns and biological role of HDAC3 in pancreatic cancer remain unclear. In this study, our data showed that a higher level of HDAC3 protein expression was found in pancreatic cancer as compared to paired paracancerous tissues. Consistently, higher expression level of HDAC3 was found in all of the eight pancreatic cancer cell lines relative to human pancreatic ductal epithelial cells (HPDE). In addition, further function analysis revealed that HDAC3 can function as oncogenic protein, which could promote pancreatic cancer cell proliferation, migration and invasion, and may increase drug resistance. Moreover, the functional involvement of HDAC3 was partially correlated with post-induction repression of P53, P27 and Bax gene transcription, acting via H3K9 deacetylation. Taken together, our data suggest that HDAC3 participates in the pathogenesis and progression of pancreatic cancer through histone modification, which might be a pivotal epigenetic target against this devastating disease.

Genetic determinants and potential therapeutic targets for pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer deaths in both men and women in the United States, carrying a 5-year survival rate of approximately 5%, which is the poorest prognosis of any solid tumor type. Given the dismal prognosis associated with PDAC, a more thorough understanding of risk factors and genetic predisposition has important implications not only for cancer prevention, but also for screening techniques and the development of personalized therapies. While screening of the general population is not recommended or practicable with current diagnostic methods, studies are ongoing to evaluate its usefulness in people with at least 5- to 10-fold increased risk of PDAC. In order to help identify high-risk populations who would be most likely to benefit from early detection screening tests for pancreatic cancer, discovery of additional pancreatic cancer susceptibility genes is crucial. Thus, specific gene-based, gene-product, and marker-based testing for the early detection of pancreatic cancer are currently being developed, with the potential for these to be useful as potential therapeutic targets as well. The goal of this review is to provide an overview of the genetic basis for PDAC with a focus on germline and familial determinants. A discussion of potential therapeutic targets and future directions in screening and treatment is also provided.

Antitumor efficacy of α-solanine against pancreatic cancer in vitro and in vivo

α-solanine, a steroidal glycoalkaloid in potato, was found to have proliferation-inhibiting and apoptosis-promoting effect on multiple cancer cells, such as clone, liver, melanoma cancer cells. However, the antitumor efficacy of α-solanine on pancreatic cancer has not been fully evaluated. In this study, we inquired into the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In the present study, we investigated the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In vitro, α-solanine inhibited proliferation of PANC-1, sw1990, MIA PaCa-2 cells in a dose-dependent manner, as well as cell migration and invasion with atoxic doses. The expression of MMP-2/9, extracellular inducer of matrix metalloproteinase (EMMPRIN), CD44, eNOS and E-cadherin were suppressed by α-solanine in PANC-1 cells. Moreover, significantly decreased vascular endothelial growth factor (VEGF) expression and tube formation of endothelial cells were discerned following α-solanine treatment. Suppressed phosphorylation of Akt, mTOR, and Stat3, and strengthen phosphorylation of β-catenin was found, along with markedly decreased tran-nuclear of NF-κB, β-catenin and TCF-1. Following the administration of α-solanine (6 µg/g for 2 weeks) in xenograft model, tumor volume and weight were decreased by 61% and 43% (p<0.05) respectively, showing decreased MMP-2/9, PCNA and VEGF expression. In conclusion, α-solanine showed beneficial effects on pancreatic cancer in vitro and in vivo, which may via suppressing the pathway proliferation, angiogenesis and metastasis.

Suppressed expression of NDRG2 correlates with poor prognosis in pancreatic cancer

Pancreatic cancer is a highly lethal disease with a poor prognosis; the molecular mechanisms of the development of this disease have not yet been fully elucidated. N-myc downstream regulated gene 2 (NDRG2), one of the candidate tumor suppressor genes, is frequently downregulated in pancreatic cancer, but there has been little information regarding its expression in surgically resected pancreatic cancer specimens. We investigated an association between NDRG2 expression and prognosis in 69 primary resected pancreatic cancer specimens by immunohistochemistry and observed a significant association between poor prognosis and NDRG2-negative staining (P=0.038). Treatment with trichostatin A, a histone deacetylase inhibitor, predominantly up-regulated NDRG2 expression in the NDRG2 low-expressing cell lines (PANC-1, PCI-35, PK-45P, and AsPC-1). In contrast, no increased NDRG2 expression was observed after treatment with 5-aza-2' deoxycytidine, a DNA demethylating agent, and no hypermethylation was detected in either pancreatic cancer cell lines or surgically resected specimens by methylation specific PCR. Our present results suggest that (1) NDRG2 is functioning as one of the candidate tumor-suppressor genes in pancreatic carcinogenesis, (2) epigenetic mechanisms such as histone modifications play an essential role in NDRG2 silencing, and (3) the expression of NDRG2 is an independent prognostic factor in pancreatic cancer.

Spiclomazine induces apoptosis associated with the suppression of cell viability, migration and invasion in pancreatic carcinoma cells

The effective treatment for pancreatic carcinoma remains critically needed. Herein, this current study showed that spiclomazine treatment caused a reduction in viability in pancreatic carcinoma cell lines CFPAC-1 and MIA PaCa-2 in vitro. It was notable in this regard that, compared with pancreatic carcinoma cells, normal human embryonic kidney (HEK-293) and liver (HL-7702) cells were more resistant to the antigrowth effect of spiclomazine. Biochemically, spiclomazine treatment regulated the expression of protein levels in the apoptosis related pathways. Consistent with this effect, spiclomazine reduced the mitochondria membrane potential, elevated reactive oxygen species, and activated caspase-3/9. In addition, a key finding from this study was that spiclomazine suppressed migration and invasion of cancer cells through down-regulation of MMP-2/9. Collectively, the proposed studies did shed light on the antiproliferation effect of spiclomazine on pancreatic carcinoma cell lines, and further clarified the mechanisms that spiclomazine induced apoptosis associated with the suppression of migration and invasion.

The role of Movat pentachrome stain and immunoglobulin G4 immunostaining in the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis is highly responsive to steroid therapy, but because it mimics pancreatic cancer, it often precipitates unnecessary surgery. Adequate diagnostic tests are needed to permit appropriate medical therapy. Lymphocytic and obliterative phlebitis are reported in the majority of cases, as are elevated IgG4-positive plasma cells, indicating their high sensitivity. Their specificities, especially when used in conjunction, however, remain largely unknown. Movat pentachrome vascular and IgG4 immunohistochemical stains were performed on a total of 15 autoimmune pancreatitis cases (11 pancreatic resections and 4 biopsies), 39 usual-type alcoholic or idiopathic chronic pancreatitis cases, 35 pancreatic ductal adenocarcinoma-associated chronic pancreatitis cases, and 29 normal pancreata. Marked and diffuse lymphocytic and obliterative venulitis were detected in all 15 cases of autoimmune pancreatitis on Movat staining (100% sensitivity). Only a single carcinoma-associated chronic pancreatitis case among all of the controls showed diffuse benign venulitis that was nonobliterative (99% specificity). Nine of 13, 9 autoimmune pancreatitis cases showed marked IgG4 immunopositivity at >or=10 positive plasma cells per x 400 field (69% sensitivity). No increased IgG4 plasma cells were found in any of 103 controls (100% specificity). In combination, all of the autoimmune pancreatitis cases had at least one (13/13) and most had both markers (9/13), whereas none of the controls had both markers. Overall, these combined stains show very promising diagnostic utility and should be considered in combination with clinical and serologic analyses in the evaluation of chronic pancreatitis suspicious for malignancy. Future validating studies on preoperative biopsies with outcome data following steroid therapy will be essential.