Molecular changes in pancreatic cancer

Early-onset pancreatic cancer: a review of molecular mechanisms, management, and survival

OBJECTIVES

Early-onset pancreatic cancer (EOPC) - defined as pancreatic cancer diagnosed before the age of 50 years - is associated with a poor prognosis as compared to later-onset pancreatic cancer (LOPC). Emerging evidence suggests that EOPC may exhibit a genetic signature and tumor biology that is distinct from that of LOPC. We review genetic mutations that are more prevalent in EOPC relative to LOPC and discuss the potential impact of these mutations on treatment and survival.

MATERIALS AND METHODS

Using PubMed and Medline, the following terms were searched and relevant citations assessed: "early onset pancreatic cancer," "late onset pancreatic cancer," "pancreatic cancer," "pancreatic cancer genes," and "pancreatic cancer targeted therapy."

RESULTS

Mutations in CDKN2, FOXC2, and SMAD4 are significantly more common in EOPC as compared to LOPC. In addition, limited data suggest that PI3KCA mutations are more frequently observed in EOPC as compared to LOPC. KRAS mutations are relatively rare in EOPC.

CONCLUSIONS

Genetic mutations associated with EOPC are distinct from those of LOPC. The preponderance of the evidence suggest that poor outcomes in EOPC are related both to advanced stage of presentation and unique tumor biology. The molecular and genetic features of EOPC warrant further investigation in order to optimize management.

Phytochemical composition, anti-inflammatory activity and cytotoxic effects of essential oils from three Pinus spp

CONTEXT

Inflammation and cell differentiation lead to a number of severe diseases. In the recent years, various studies focused on the anti-inflammatory and anticancer activity of essential oils (EOs) of numerous plants, including different Pinus species.

OBJECTIVE

The phytochemical composition, anti-inflammatory and cytotoxic activity of EOs from needles and twigs of Pinus heldreichii Christ (Pinaceae) and P. peuce Griseb., and from needles, twigs and cones of P. mugo Turra were determined.

MATERIALS AND METHODS

For separation and identification of the EOs, gas chromatography/flame ion detector (GC/FID) and GC/mass spectrometry were performed. The amount of secreted IL-6 in a lipopolysaccharide (LPS)-stimulated macrophage model was quantified (concentration of oils: 0.0001-0.2%, 3 h incubation). Cytotoxicity on the cancer cell lines HeLa, CaCo-2 and MCF-7 were determined using a MTT (Thiazolyl Blue Tetrazolium Bromide) assay (concentration of oils: 0.001-0.1%, 24 h incubation).

RESULTS

The most prominent members in the oils include: δ-3-carene, α-pinene and linalool-acetate (P. mugo); α-pinene, β-phellandrene and β-pinene (P. peuce); limonene, α-pinene and (E)-caryophyllene (P. heldreichii). EOs showed significant cytotoxic effects on cancer cell lines (IC50 0.007 to >0.1%), with a reduction in cell viability with up to 90% at a concentration of 0.1%, and anti-inflammatory activity (IC50 0.0008-0.02%) with a reduction of IL-6 secretion with up to 60% at a concentration of 0.01%.

DISCUSSION AND CONCLUSION

The EOs of needles and twigs from P. peuce and P. heldreichii as well as of needles, twigs and cones of P. mugo can be considered as promising agents for anticancer and anti-inflammatory drugs.

Punicalagin, a polyphenol from pomegranate fruit, induces growth inhibition and apoptosis in human PC-3 and LNCaP cells

Prostate cancer (PCa) is an international health problem and search for its effective treatment is in progress. Punicalagin (PN), polyphenol from pomegranate fruit, is known to exhibit potent anticancer activity in lung, breast and cervical cells. However, there is paucity of information on its effect in PCa. This study evaluated anti-proliferative effects of PN and its effects on extrinsic pathway of apoptosis in PCa cells, and angiogenesis in chicken chorioallantoic membrane (CAM). Antioxidant activities of PN were determined by 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging and inhibition of lipid peroxidation (LPO) methods. PCa (PC-3 and LNCaP) and normal prostate (BPH-1) cells were cultured and treated with PN (10, 50 and 100 μM). Cytotoxicity and viability effects of PN were determined by lactate dehydrogenase (LDH) and XTT assays, respectively. Antiangiogenic effects were measured using CAM assay, while apoptosis was assessed by DNA fragmentation, enrichment factor by Cell Death Detection ELISA kit and expressions of caspases-3 and -8. Results showed that PN (10-200 μM) significantly scavenged DPPH and inhibited LPO in a concentration-dependent manner. Furthermore, PN (10-100 μM) concentration-dependently inhibited viability in PC-3 and LNCaP, while viability in BPH-1 was insignificantly affected. PN had low toxicity on cells in vitro at concentrations tested. Also, PN (100 μM) increased enrichment factor in PC-3 (2.34 ± 0.05) and LNCaP (2.31 ± 0.26) relative to control (1.00 ± 0.00). In addition, PN (50 μM) decreased the network of vessels in CAM, suggesting its anti-angiogenic effect. Moreso, PN increased the expressions of caspases-3 and -8 in PC-3. Overall, PN exerts anti-proliferative activity in PCa cells via induction of apoptosis and anti-angiogenic effect.

Antisense inhibition of microRNA-21 and microRNA-221 in tumor-initiating stem-like cells modulates tumorigenesis, metastasis, and chemotherapy resistance in pancreatic cancer

Our preliminary studies identified a small population side population (SP) cells in pancreatic cancer cells with stem cell-like properties, which were able to induce fast and aggressive tumor formation in nude mice. Gene expression analysis showed a significant difference in the expression of more than 1,300 genes in SP cells, among which a highly significant difference in microRNA expression of miR-21 and miR-221 between SP and NSP cells was identified. SP cells were identified and characterized by flow cytometry using Hoechst 33342 dye staining from a highly metastatic human pancreatic cancer cell line (L3.6pl). Antagomir transfection was performed using miRNA-21 and miRNA-221 antisense oligonucleotides (ASOs) and followed by detection of cell apoptosis, cell cycle progression, chemosensitivity, and invasion. Sorted SP cells from gemcitabine-resistant L3.6pl cells (L3.6pl(Gres)-SP) cells were orthotopically implanted in nude mice with or without miRNA-21 and miRNA-221 ASOs mono- and combination therapy. The administration of antagomir-21 and antagomir-221 significantly reduced the SP cell fraction, decreased SP cell differentiation, and downstream gene regulation, and thereby induced reduction of L3.6pl cell proliferation, invasion, and chemoresistance against gemcitabine and 5-Fluorouracil. Combination of ASOs therapy against miRNA-21 and miRNA-221 significantly inhibited primary tumor growth and metastasis compared to single antagomir treatment, especially, in L3.6plGres-SP-induced pancreatic tumor growth in vivo. These findings further indicate that the inhibition of miR-21 and miR-221 appear particularly suitable to target stem-like subpopulations and address their specific biological function to promote tumor progression in pancreatic cancer.

Key role of dual specificity kinase TTK in proliferation and survival of pancreatic cancer cells

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is among the most aggressive human malignancies with an overall 5-year survival rate of <5%. Despite significant advances in treatment of the disease during the past decade, the median survival rate (∼6 months) has hardly improved, warranting the need to identify novel targets for therapeutic approaches.

METHODS

Quantitative real time PCR, western blot analyses and immunohistochemical staining of tissue microarrays were used to analyse the expression of TTK gene in primary PDAC tissues and cell lines. To inhibit TTK kinase expression in a variety of pancreatic cancer cell lines, RNA interference was used. Functional roles of this kinase in the context of PDAC were studied using cell proliferation, viability and anchorage-independent growth assays. Western blotting, fluorescence-activated cell sorting analyses and fluorescence microscopy were used to gain mechanistic insight into the functional effects.

CONCLUSIONS

We show that the dual specificity kinase TTK (also known as Mps1), is strongly overexpressed in human PDAC. Functionally, cell proliferation was significantly attenuated following TTK knockdown, whereas apoptosis and necrosis rates were significantly increased. In addition, anchorage-independent growth, a hallmark of malignant transformation and metastatic potential, was strongly impaired in the absence of TTK gene function. Interestingly, immortalised normal pancreatic hTERT-HPNE cells were not affected by loss of TTK function. Mechanistically, these effects in cancer cells were associated with increased formation of micronuclei, suggesting that loss of TTK function in pancreatic cancer cells results in chromosomal instability and mitotic catastrophe. Taken together, our data show that TTK function is critical for growth and proliferation of pancreatic cancer cells, thus establishing this kinase as an interesting new target for novel therapeutic approaches in combating this malignancy.

Composition and cytotoxic activity of essential oils from Xylopia aethiopica (Dunal) A. Rich, Xylopia parviflora (A. Rich) Benth.) and Monodora myristica (Gaertn) growing in Chad and Cameroon

Background

Cancer has become a global public health problem and the search for new control measures is urgent. Investigation of plant products such as essential oils from Monodora myristica, Xylopia aethiopica and Xylopia parviflora might lead to new anticancer therapy. In this study, we have investigated the antineoplastic activity of essential oils from fruits of these plants growing in Chad and Cameroon.

Methods

The essential oils obtained by hydrodistillation of fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora collected in Chad and Cameroon were analyzed by GC-FID and GC-MS and investigated for their antiproliferative activity against the breast cancer cell line (MCF7).

Results

Overall, monoterpenes were mostly found in the six essential oils. Oils from X. aethiopica and X. parviflora from Chad and Cameroon mainly contain β-pinene at 24.6%, 28.2%, 35.7% and 32.9% respectively. Monodora myristica oils from both origins contain mainly α-phellandrene at 52.7% and 67.1% respectively. The plant origin did not significantly influence the chemical composition of oils. The six essential oils exerted cytotoxic activity against cancer (MCF-7) and normal cell lines (ARPE-19), with more pronounced effect on neoplastic cells in the majority of cases. The highest selectivity was obtained with the essential oils of X. parviflora from Chad and Cameroon (5.87 and 5.54) which were more cytotoxic against MCF-7 than against normal cell line (ARPE-19) with IC₅₀ values of 0.155 μL/mL and 0.166 μL/mL respectively.

Conclusions

Essential oils from fruits of Monodora myristica, Xylopia aethiopica and Xylopia parviflora have shown acceptable antineoplastic potency, and might be investigated further in this regard.

Celecoxib synergizes human pancreatic ductal adenocarcinoma cells to sorafenib-induced growth inhibition

BACKGROUND

Pancreatic ductal adenocarcinoma is frequently associated with aberrant activation of the Ras/Raf/MAPK pathway and cyclooxygenase-2 (COX-2) overexpression. This study evaluated the potential for combining the multikinase inhibitor sorafenib and the specific COX-2 inhibitor celecoxib as therapy in pancreatic ductal adenocarcinoma cells.

METHODS

BxPC-3, MIAPaCa-2, PANC-1 and AsPC-1 pancreatic adenocarcinoma cells were exposed to sorafenib and celecoxib combined treatment in vitro. Cell viability and various growth promoting and survival signaling pathways were monitored by MTT, flow cytometry and Western blotting.

RESULTS

Combined treatment with sorafenib and celecoxib synergistically inhibited pancreatic adenocarcinoma cell proliferation. This regimen produced combination index (CI) values between 0.67 and 0.92 for the various cell lines, indicating significant synergistic interactions between sorafenib and celecoxib, which also markedly inhibited the migratory capacity. The growth inhibition was associated with an accumulation of cells in the G(0)/G(1) phase of the cell cycle and induction of apoptosis. These changes were accompanied by a significant reduction of p21(WAF1/Cip1) levels, where celecoxib sensitized the cells to sorafenib-mediated p21(WAF1/Cip1) suppression.

CONCLUSION

These results suggest that combined treatment with sorafenib and celecoxib synergistically induce growth inhibition and apoptosis in pancreatic adenocarcinoma cells through a process involving p21(WAF1/Cip1) suppression.

Frequent mutation of isocitrate dehydrogenase (IDH)1 and IDH2 in cholangiocarcinoma identified through broad-based tumor genotyping

Cancers of origin in the gallbladder and bile ducts are rarely curable with current modalities of cancer treatment. Our clinical application of broad-based mutational profiling for patients diagnosed with a gastrointestinal malignancy has led to the novel discovery of mutations in the gene encoding isocitrate dehydrogenase 1 (IDH1) in tumors from a subset of patients with cholangiocarcinoma. A total of 287 tumors from gastrointestinal cancer patients (biliary tract, colorectal, gastroesophageal, liver, pancreatic, and small intestine carcinoma) were tested during routine clinical evaluation for 130 site-specific mutations within 15 cancer genes. Mutations were identified within a number of genes, including KRAS (35%), TP53 (22%), PIK3CA (10%), BRAF (7%), APC (6%), NRAS (3%), AKT1 (1%), CTNNB1 (1%), and PTEN (1%). Although mutations in the metabolic enzyme IDH1 were rare in the other common gastrointestinal malignancies in this series (2%), they were found in three tumors (25%) of an initial series of 12 biliary tract carcinomas. To better define IDH1 and IDH2 mutational status, an additional 75 gallbladder and bile duct cancers were examined. Combining these cohorts of biliary cancers, mutations in IDH1 and IDH2 were found only in cholangiocarcinomas of intrahepatic origin (nine of 40, 23%) and in none of the 22 extrahepatic cholangiocarcinomas and none of the 25 gallbladder carcinomas. In an analysis of frozen tissue specimens, IDH1 mutation was associated with highly elevated tissue levels of the enzymatic product 2-hydroxyglutarate. Thus, IDH1 mutation is a molecular feature of cholangiocarcinomas of intrahepatic origin. These findings define a specific metabolic abnormality in this largely incurable type of gastrointestinal cancer and present a potentially new target for therapy.

2-Triazenoazaindoles: α novel class of triazenes inducing transcriptional down-regulation of EGFR and HER-2 in human pancreatic cancer cells

Pancreatic cancer is a complex malignancy arising from the accumulation of genetic and epigenetic defects in the affected cells. Standard chemotherapy for patients with advanced disease shows only modest effects and is associated with considerable toxicity. Overexpression or aberrant activation of members of the epidermal growth factor receptor tyrosine kinase family, which includes EGFR and HER-2, occurs frequently and is associated with multiple drug resistance and decreased patient survival. In this study, we have investigated the therapeutic potential of AS104, a novel compound of the triazene class, with potential inhibitory effects on EGFR. We found that treatment of cells with AS104 causes significant reduction of cell growth and metabolic activity in four human pancreatic cancer cell lines. Furthermore, we show that the AS104-mediated induction of apoptotic cell death is associated with stimulation of autophagy in a dose-dependent manner. Treatment of cells with AS104 results in significant down-regulation of EGFR and HER-2 expression and activity and subsequent inhibition of downstream signaling proteins. Quantitative RT-PCR analysis and assays with proteasome inhibitors revealed that AS104 regulates the expression of EGFR and HER-2 at the transcriptional level. These findings provide for the first time experimental evidence for efficacy of AS104 in the simultaneous transcriptional repression of EGFR and HER-2 genes and suggest that AS104 may have therapeutic potential in the treatment of pancreatic cancers that express high levels of the aforementioned receptor tyrosine kinases.

Adjuvant therapy for pancreas adenocarcinoma: where are we going?

Evaluation of: Neoptolemos JP, Stocken DD, Bassi C et al. Adjuvant chemotherapy with fluorouracil plus folinic acid vs. gemcitabine following pancreatic cancer resection: a randomized controlled trial. JAMA 304(10), 1073-1081 (2010). Over the last decade, adjuvant therapy in the treatment of resected pancreas adenocarcinoma has had its value established. Such treatment incrementally increases 5-year survivorship and delays time to tumor recurrence. The backbone of adjuvant therapy is the single-agent gemcitabine, based primarily on results from the Charité Onkologie Clinical (CONKO)-001 study. Based on the combined results of the European Study Group for Pancreas Cancer (ESPAC)-1 and ESPAC-3 trials, Neoptolemos and colleagues have established both bolus 5-fluorouracil and leucovorin and gemcitabine as standard options for resected pancreatic cancer. Gemcitabine remains the main standard therapy based on its ease of administration and a more favorable toxicity profile; however, there is now a clearly validated alternate option of 5-fluororuacil and leucovorin based on the results of ESPAC-3. Moving forward, the integration of novel cytotoxic and targeted agents into adjuvant therapy, along with refining the role of neoadjuvant therapy for patients with resectable pancreas cancer, will hopefully accrue a more substantial improvement in outcome for patients with resected pancreas adenocarcinoma.

Emerging therapies in pancreas cancer

Pancreas cancer has a grave prognosis and treatment options remain limited despite advancement in anti-cancer chemotherapeutics. This review provides an overview of the emerging therapies for pancreas cancer, focusing on novel signal transduction inhibitors (insulin-like growth factor receptor, hedgehog/Smo, PI3k/Akt/mTOR) and cytotoxics (nab-paclitaxel) that are currently in clinical development. Despite the impact molecularly targeted agents have on other tumor types, their application without cytotoxics in pancreas cancer remains limited. In addition, recent report of the superiority of an intensive cytotoxic regimen using fluorouracil, irinotecan and oxaliplatin (FOLFIRINOX) over gemcitabine reminded us of the importance of cytotoxics in this disease. As such, the future of pancreas cancer therapy may be combination regimens consisting of cytotoxics and molecularly targeted agents.

Serum APRIL, a potential tumor marker in pancreatic cancer

BACKGROUND

A proliferation-inducing ligand (APRIL) is a newly-found member in the tumor necrosis factor (TNF) superfamily. Our previous studies have already confirmed that APRIL is overexpressed in pancreatic cancer tumors, however, it is not expressed or has a weak expression in normal pancreatic gland tissues. Furthermore, there is no report on serum APRIL in patients with pancreatic diseases. Herein, in order to explore the clinical implication of serum APRIL in patients with pancreatic cancer, serum APRIL, together with carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9, was examined.

METHODS

Serum APRIL was tested by ELISA in patients with pancreatic cancer. Meanwhile, two other conventional serum tumor markers, CEA and CA19-9, were measured by Elecsys 2010 Chemistry Analyzer.

RESULTS

Serum APRIL increased in patients with pancreatic cancer, which proved a positive correlation with CEA and CA19-9. When the diagnosis of benign or malignant condition was examined by one tumor marker, the sensitivity of APRIL alone (70.1%) was greater than that of CEA alone (56.7%), and the specificity of APRIL alone (85.5%) was higher than that of CA19-9 alone (83.6%). When examined by a combination of two markers, the sensitivity of the combination of APRIL and CA19-9 was the highest (88.1%), as it was compared with that of APRIL alone, CEA alone and APRIL+CEA, p<0.05. In addition, serum APRIL also correlated with the tumor stage and postoperative survival in patients with pancreatic cancer.

CONCLUSIONS

Our results indicate that serum APRIL, as a potential biomarker, has a positive diagnosis and prognosis value for pancreatic cancer. Moreover, the combination assay of APRIL and CA19-9 is highly sensitive to pancreatic cancer.

A Cancer and Leukemia Group B phase II study of sunitinib malate in patients with previously treated metastatic pancreatic adenocarcinoma (CALGB 80603)

BACKGROUND

The Cancer and Leukemia Group B (CALGB) conducted a phase II study evaluating sunitinib in patients with progressive metastatic pancreas adenocarcinoma following prior gemcitabine-based therapy (trial CALGB 80603; ClinicalTrials.gov identifier, NCT00397787). The primary endpoint was to determine the disease control rate (DCR) as measured by the Response Evaluation Criteria in Solid Tumors (complete response, partial response [PR], and stable disease) at 6 weeks.

PATIENTS AND METHODS

Patients aged ≥18 years with an Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2 and with progressive pancreas adenocarcinoma following treatment with gemcitabine were eligible. Sunitinib was dosed at 50 mg orally days 1-28, every 42 days (1 cycle). The statistical plan called for a three-stage design. A DCR ≥15% was considered worthy of further study.

RESULTS

In total, 77 patients were enrolled. Forty-two (54.6%) enrollees were male. The median age was 65 years. The ECOG performance status score distribution was: 0, 39%; 1, 50%; 2, 11%. The DCR was 21.6%; one patient (1.4%) had a PR and 15 patients (20.3%) had stable disease as their best response. The progression-free survival time was 1.31 months (95% confidence interval [CI] 1.25-1.38 months) and overall survival time was 3.68 months (95% CI, 3.06-4.24 months).

CONCLUSIONS

The study met its primary endpoint; however sunitinib had minimal activity and moderate toxicity in a population of gemcitabine-refractory pancreas adenocarcinoma patients. For future studies, limiting enrollment to patients with an ECOG performance status score of 0-1 is recommended.

Enhancing chemosensitivity to gemcitabine via RNA interference targeting the catalytic subunits of protein kinase CK2 in human pancreatic cancer cells

Background

Pancreatic cancer is a complex genetic disorder that is characterized by rapid progression, invasiveness, resistance to treatment and high molecular heterogeneity. Various agents have been used in clinical trials showing only modest improvements with respect to gemcitabine-based chemotherapy, which continues to be the standard first-line treatment for this disease. However, owing to the overwhelming molecular alterations that have been reported in pancreatic cancer, there is increasing focus on targeting molecular pathways and networks, rather than individual genes or gene-products with a combination of novel chemotherapeutic agents.

Methods

Cells were transfected with small interfering RNAs (siRNAs) targeting the individual CK2 subunits. The CK2 protein expression levels were determined and the effect of its down-regulation on chemosensitization of pancreatic cancer cells was investigated.

Results

The present study examined the impact on cell death following depletion of the individual protein kinase CK2 catalytic subunits alone or in combination with gemcitabine and the molecular mechanisms by which this effect is achieved. Depletion of the CK2α or -α' subunits in combination with gemcitabine resulted in marked apoptotic and necrotic cell death in PANC-1 cells. We show that the mechanism of cell death is associated with deregulation of distinct survival signaling pathways. Cellular depletion of CK2α leads to phosphorylation and activation of MKK4/JNK while down-regulation of CK2α' exerts major effects on the PI3K/AKT pathway.

Conclusions

Results reported here show that the two catalytic subunits of CK2 contribute differently to enhance gemcitabine-induced cell death, the reduced level of CK2α' being the most effective and that simultaneous reduction in the expression of CK2 and other survival factors might be an effective therapeutic strategy for enhancing the sensitivity of human pancreatic cancer towards chemotherapeutic agents.

Gene-expression profiling in pancreatic cancer

Pancreatic cancer has one of the worst prognoses, owing principally to a late diagnosis and the absence of good treatments. In the last 5 years, up to 12 molecular pathways involved in pancreatic cancer have been described. Global gene-expression profiling and the use of microarray databases have allowed the identification of hundreds of genes that are differentially expressed in pancreatic cancer. However, validation of these genes as biomarkers for early diagnosis, prognosis or treatment efficacy is still incomplete. Additionally, microRNAs have emerged as a potential source of variation between cancer and normal samples, and several of them have been identified as being deregulated in pancreatic tumors. An integrative point of view in the study of pancreatic cancer that makes use of all the whole-genome technologies has revealed several molecular mechanisms that affect pancreatic cancer development. These results should encourage the use of more personalized medicine in this pathology. Recent developments and future perspectives are discussed.

PAR-4 as a possible new target for pancreatic cancer therapy

IMPORTANCE OF THE FIELD

Pancreatic cancer (PC) is a deadly disease that is intractable to currently available treatment regimens. Although well described in different tumors types, the importance of apoptosis inducer prostate apoptosis response-4 (Par-4) in PC has not been appreciated. PC is an oncogenic kras driven disease, which is known to downregulate Par-4. Therefore, this review highlights its significance and builds a strong case supporting the role of Par-4 as a possible therapeutic target in PC.

AREAS COVERED IN THIS REVIEW

Literature-based evidence spanning the last 15 years on Par-4 and its significance in PC.

WHAT THE READER WILL GAIN

This review provides comprehensive knowledge of the significance of Par-4 and its association with kras status in PC, along with the crosstalk with crucial resistance and survival molecules NF-kappaB and Bcl-2 that ultimately are responsible for the overall poor outcome of different therapeutic approaches in this disease.

TAKE HOME MESSAGE

Par-4 holds promise as a potential therapeutic target that can be induced by chemopreventive agents and small-molecule inhibitors either alone or in combination with standard chemotherapeutics leading to selective apoptosis in PC cells. It also acts as a chemosensitizer and therefore warrants further clinical investigations in this disease.