Pancreatic cancer - a continuing challenge in oncology

Celecoxib combined with salirasib strongly inhibits pancreatic cancer cells in 2D and 3D cultures

Background/Aim: Pancreatic adenocarcinoma is a highly malignant tumor. Synergistic combinations of anticancer agents for the effective treatment of pancreatic cancer patients are urgently needed. Here, we investigated the combined effect of celecoxib (CEL) and salirasib (SAL) on pancreatic cancer cells. Methods: Cell viability and apoptosis were measured by the trypan blue assay, three-dimensional cultures, propidium iodide staining, and caspase-3 assay. NF-κB activation and the protein levels of Akt, pAkt, and Bcl-2 were determined by the luciferase reporter assay and western blot. Results: Co-treatment with CEL and SAL had stronger effects on decreasing cell viability and inducing apoptosis in Panc-1 cells as compared with each agent individually. This combination strongly inhibited NF-κB activity and reduced pAkt and Bcl-2 levels in Panc-1 cells. Conclusion: SAL in combination with CEL may represent a new approach for effective inhibition of pancreatic cancer.

Biochanin A reduces pancreatic cancer survival and progression

Pancreatic cancer has dismally low mean survival rates worldwide. Only a few chemotherapeutic agents including gemcitabine have been shown to improve the survival of pancreatic cancer patients. Biochanin A, an isoflavone, is known to exert an anticancer effect on various cancer types. In this study, we examined the anticancer properties of biochanin A on pancreatic cancer cells. The effect of biochanin A on cellular survival, apoptosis, and proliferation was analyzed using MTT, flow cytometry, and colony formation assay. The effect of biochanin A on pancreatic cancer's mitogenic signaling was determined using western blot analysis. Migration assay and zymography were used to determine biochanin A's effect on pancreatic cancer progression. Biochanin A induced dose-dependent toxicity on pancreatic cancer cells (Panc1 and AsPC-1). It reduced colony formation ability of Panc1 cells and induced dose-dependent apoptosis. Activation of Akt and MAPK was inhibited. Furthermore, the migratory and invasive potential of the cancer cells was also reduced. The results suggest that biochanin A is effective in reducing pancreatic cancer cell survival by inhibiting their proliferation and inducing apoptosis. It affects mitogenic, migratory, and invasive processes involved in cancer progression. These findings may lead to novel approaches to treat pancreatic cancer using isoflavones in combination with other therapeutic drugs.

The use of a novel MUC1 antibody to identify cancer stem cells and circulating MUC1 in mice and patients with pancreatic cancer

BACKGROUND AND OBJECTIVES

MUC1 is over-expressed and aberrantly glycosylated in >60% of human pancreatic cancer (PC). Development of novel approaches for detection and/or targeting of MUC1 are critically needed and should be able to detect MUC1 on PC cells (including cancer stem cells) and in serum.

METHODS

The sensitivity and specificity of the anti-MUC1 antibody, TAB 004, was determined. CSCs were assessed for MUC1 expression using TAB 004-FITC on in vitro PC cell lines, and on lineage(-) cells from in vivo tumors and human samples. Serum was assessed for shed MUC1 via the TAB 004 EIA.

RESULTS

In vitro and in vivo, TAB 004 detected MUC1 on >95% of CSCs. Approximately, 80% of CSCs in patients displayed MUC1 expression as detected by TAB 004. Shed MUC1 was detected serum in mice with HPAF-II (MUC1(high) ) but not BxPC3 tumors (MUC1(low)). The TAB 004 EIA was able to accurately detect stage progression in PC patients.

CONCLUSIONS

The TAB 004 antibody may be explored as a therapeutic targeting agent for CSCs in PC. The TAB 004 EIA detected circulating MUC1 in a stage-dependent manner in patients with PC and thus may be explored as a PC stage diagnostic biomarker.

Effects of 12-O-tetradecanoylphorbol-13-acetate in combination with gemcitabine on Panc-1 pancreatic cancer cells cultured in vitro or Panc-1 tumors grown in immunodeficient mice

In the present study, the effects of 12-O-tetra-decanoylphorbol-13-acetate (TPA) alone or in combination with gemcitabine on the growth of Panc-1 pancreatic cancer cells cultured in vitro or grown in NCr immunodeficient nude mice were investigated. Combinations of TPA and gemcitabine synergi-stically inhibited the growth and induced apoptosis in Panc-1 cells. The combination of TPA (0.16 nM) and gemcitabine (0.5 µM) induced a marked increase in phosphorylated c-Jun NH2-terminal kinase (JNK) in the Panc-1 cells. In animal experiments, NCr nude mice with established Panc-1 tumors received daily intraperitoneal (i.p.) injections of TPA (50 ng/g body weight/day) or gemcitabine (0.5 µg/g body weight/day) alone or in combination for 26 days. Treatment with daily i.p. injections of low doses of TPA or gemcitabine alone had a modest inhibitory effect on the growth of the tumors. However, the combination of low doses of TPA and gemcitabine more potently inhibited the growth of Panc-1 tumors than either agent used individually. Treatment with TPA or gemcitabine alone or in combination did not affect the body weight of the animals. Clinical trials with TPA alone or in combination with gemcitabine on patients with pancreatic cancer are warranted in order to confirm our results.

High gene expression of semaphorin 5A in pancreatic cancer is associated with tumor growth, invasion and metastasis

Semaphorin 5A (SEMA5A) is an axonal regulator molecule, which belongs to the Semaphorin family of proteins. Previously, we identified SEMA5A as a putative marker for aggressive pancreatic tumors. However, the expression, localization and functional significance of SEMA5A in pancreatic tumors remain unclear. In our study, we hypothesized that SEMA5A expression modulates pancreatic tumor growth and metastasis. We analyzed the constitutive expression and localization of SEMA5A in patient pancreatic tumors (n = 33) and unmatched normal pancreatic (n = 8) tissues and human pancreatic cancer cell lines (n = 16) with different histopathological characteristics. We observed significantly higher expression of SEMA5A protein expression (p < 0.05) in human pancreatic tumor tissue samples compared to normal pancreatic tissues. Similarly, the pancreatic cancer cell lines with higher tumorigenic and metastatic potentials as xenografts in nude mice expressed higher levels of SEMA5A mRNA compared to those with lower tumorigenic and metastatic potentials. Furthermore, we examined the functional role of SEMA5A in pancreatic tumor growth and invasion. Ectopic expression of mouse full-length Sema5A in Panc1 (SEMA5A negative) cells significantly (p < 0.05) enhanced tumorigenesis, growth and metastasis in vivo as well as proliferation, invasiveness and homotypic aggregation in vitro. Together, these data demonstrate that the expression of SEMA5A in pancreatic cancer cells regulates tumorigenesis, growth, invasion and metastasis, and it also suggests a novel target for diagnosis and treatment of pancreatic cancer.

H pylori infection causes chronic pancreatitis in Mongolian gerbils

AIM: To investigate whether chronic H pylori infection has the potential to induce pancreatitis in the Mongolian gerbil model, and whether it is dependent on an intact type IV secretion system.

METHODS: Mongolian gerbils were infected with wild type (WT) H pylori typeIstrain B128 or its isogenic mutant B128 ΔcagY (defective type IV secretion). After seven months of infection, H pylori was reisolated from antrum and corpus and H pylori DNA was analyzed by semi-nested polymerase chain reaction (PCR). Inflammation and histological changes were documented in the gastric antrum, corpus, and pancreas by immunohistochemistry. Cytokine mRNA, gastric pH, plasma gastrin, amylase, lipase, and glucose levels were determined.

RESULTS: The H pylori infection rate was 95%. Eight infected animals, but none of the uninfected group, developed transmural inflammation and chronic pancreatitis. Extensive interstitial fibrosis and inflammation of the pancreatic lobe adjacent to the antrum was confirmed by trichrome stain, and immuno-histochemically. Pro-inflammatory cytokine mRNA was significantly increased in the antral mucosa of all infected gerbils. In the corpus, only cytokine levels of WT-infected animals and those developing transmural inflammation and pancreatitis were significantly increased. Levels of lipase, but not glucose or amylase levels, were significantly reduced in the pancreatitis group. H pylori DNA was detected in infected antral and corpus tissue, but not in the pancreas.

CONCLUSION: H pylori infection is able to induce chronic pancreatitis in Mongolian gerbils independently of the type IV secretion system, probably by an indirect mechanism associated with a penetrating ulcer.

Matrix metalloproteinase inhibitor RO 28-2653 decreases liver metastasis by reduction of MMP-2 and MMP-9 concentration in BOP-induced ductal pancreatic cancer in Syrian Hamsters: inhibition of matrix metalloproteinases in pancreatic cancer

BACKGROUND

Matrix metalloproteinases (MMP) are proteolytic enzymes which degrade the extracellular matrix and therefore play an important role in metastasis. However, the impact of MMP inhibitors (MMPI) on pancreatic cancer is still unclear. Thus we evaluated the influence of selective MMPI Ro 28-2653 on the incidence of liver metastases and the concentration of MMP-2 and MMP-9 in ductal pancreatic adenocarcinoma in Syrian hamster.

MATERIAL AND METHODS

One hundred and thirty male Syrian hamsters were randomised into 8 groups (Gr.1-3: n=15, Gr.4-8: n=17). Pancreatic cancer was induced by weekly subcutaneous injection of 10mg N-nitrosobis-2-oxopropylamin (BOP)/kg body weight (Gr.4-8) while healthy control Gr. 1-3 received 0.5 ml sodium chloride 0.9%. Gr.1 and 4 had free access to a standard diet, Gr. 2, 3 and 5-8 received a diet rich in polyunsaturated fatty acids, which increases liver metastasis in this model. In week 17 oral therapy started: Gr.3 and 6: 60 mg Eudragit/kg body weight/d (vehicle of MMPI), Gr.7 and 8: 40 mg, respectively, 120 mg RO 28-2653/kg body weight/d; Gr.1, 2, 4, 5: no therapy. After 30 weeks all hamsters were sacrificed and histopathologically examined. Additionally concentrations of MMP-2 and MMP-9 were measured in non-metastatic liver and liver metastases.

RESULTS

Concentrations of MMP-2 and MMP-9 in liver metastases were decreased by high- and low-dose therapy with MMPI. Furthermore, the incidence of liver metastases was significantly reduced by low-dose therapy with Ro 28-2653.

CONCLUSION

Low-dose therapy with Ro 28-2653 decreased liver metastasis due to an inhibition of MMP-2 and MMP-9 concentration in ductal pancreatic cancer.

Early diagnosis of pancreatobiliary duct malignancies by brush cytology and biopsy

Two hundred and five preoperative intraductal samplings (brushing and biopsy) were evaluated from 113 patients with biliary or Wirsung duct strictures. One hundred and three strictures could be specified by histology of the operative specimens, autopsy, or by the patients' clinical course. Preoperative diagnostic efficacy depended on the tumor location (it was the best for ampullary and para-papillary tumors), but the average quantitative indices for sensitivity, absolute sensitivity, specificity, positive and negative predictive values, diagnostic accuracy of cytology were 53%, 20%, 100%, 100%, 25%, 59%, respectively. The same values for biopsy were 43%, 34%, 100%, 100%, 36% and 56%. These figures improved after simultaneous cytology and biopsy. Close cooperation with the endoscopist was necessary in cases of negative, inconclusive and dysplastic (27%) samples. Repetition of sampling improved the results by 8%. Among the 26 preoperative false negative cases, sampling-, technical- and interpretative errors occurred in 84%, 4% and 12%, respectively. Revision of samples revealed 4 malignant cases among the false negative cytologic brushings. Reclassification of specimens considering the latest criteria - primary and secondary malignant features, pancreatic intraepithelial neoplasia (PanINs), etc. - resulted in improvement of the diagnostic efficiency.

Role of inflammation in pancreatic carcinogenesis and the implications for future therapy

BACKGROUND

The link between inflammation and pancreatic cancer has been observed for a number of gastrointestinal neoplasms. This review examines the role of inflammation in pancreatic carcinogenesis and how it can be utilised to develop new therapies against pancreatic cancer.

METHODS

A literature review of Pubmed, Medline and Web of Science databases was undertaken using the key words, pancreatic cancer, inflammation, inducible nitric oxide, interleukins, pro-inflammatory cytokines, cyclooxygenase-2, NF-kappa B, reactive oxygen species, DNA adducts, lipoxygenases, chemoprevention.

RESULTS

Epidemiological evidence and molecular studies both in vitro and in vivo all support the hypothesis that inflammation plays an important in the initiation and progression of pancreatic tumours.

CONCLUSION

Sustained damage caused by chronic inflammation may precede the onset of frank malignancy by a significant interval. As such, suppression of inflammatory changes and oxidative damage, may help delay or even prevent the inception of pancreatic neoplasia.