Drugs in preclinical and early-stage clinical development for pancreatic cancer

Machine learning-based approach for automated classification of cell and extracellular matrix using nanomechanical properties

Fibrosis characterized by excess accumulation of extracellular matrix (ECM) due to complex cell-ECM interactions plays a pivotal role in pathogenesis. Herein, we employ the pancreatic ductal adenocarcinoma (PDAC) model to investigate dynamic alterations in nanomechanical attributes arising from the cell-ECM interactions to study the fibrosis paradigm. Several segregated studies performed on cellular and ECM components fail to recapitulate their complex collaboration. We utilized collagen and fibronectin, the two most abundant PDAC ECM components, and studied their nanomechanical attributes. We demonstrate alteration in morphology and nanomechanical attributes of collagen with varying thicknesses of collagen gel. Furthermore, by mixing collagen and fibronectin in various stoichiometry, their nanomechanical attributes were observed to vary. To demonstrate the dynamicity and complexity of cell-ECM, we utilized Panc-1 and AsPC-1 cells with or without collagen. We observed that Panc-1 and AsPC-1 cells interact differently with collagen and vice versa, evident from their alteration in nanomechanical properties. Further, using nanomechanics data, we demonstrate that ML-based techniques were able to classify between ECM as well as cell, and cell subtypes in the presence/absence of collagen with higher accuracy. This work demonstrates a promising avenue to explore other ECM components facilitating deeper insights into tumor microenvironment and fibrosis paradigm.

Dihydrochalcones as antitumor agents

Dihydrochalcones are a class of secondary metabolites, possessing several biological properties such as antitumor, antioxidant, antibacterial, antidiabetic, estrogenic, anti-inflammatory, antithrombotic, antiviral, neuroprotective and immunomodulator properties; therefore, they are currently considered promising candidates in the drug discovery process. This review intend to debate their pharmacological actions with a particular attention to their antitumor activity against a panel of cancer cell-lines and to the description of the inhibition mechanisms of cell proliferation such as the regulation of angiogenesis, apoptosis, etc etc.

GSK2126458 has the potential to inhibit the proliferation of pancreatic cancer uncovered by bioinformatics analysis and pharmacological experiments

BACKGROUND

Pancreatic cancer is one of the most serious digestive malignancies. At present, there is an extreme lack of effective strategies in clinical treatment. The purpose of this study is to identify key genes and pathways in the development of pancreatic cancer and provide targets for the treatment of pancreatic cancer.

METHODS

GSE15471 and GSE62165 were used to screen differentially expressed genes by GEO2R tool. Hub genes prognostic potential assessed using the GEPIA and Kaplan-Meier plotter databases. The drug susceptibility data of pan-cancer cell lines is provided by The Genomics of Drug Sensitivity in Cancer Project (GDSC). Finally, the effects of PI3K-Akt signaling pathway inhibitors on cell viability of pancreatic cancer cells were detected by cell proliferation and invasion assays.

RESULTS

A total of 609 differentially expressed genes were screened and enriched in the focal adhesion, phagosome and PI3K-Akt signaling pathway. Of the 15 hub genes we found, four were primarily associated with the PI3K-Akt signaling pathway, including COL3A1, EGF, FN1 and ITGA2. GDSC analysis showed that mTOR inhibitors are very sensitive to pancreatic cancer cells with mutations in EWSR1.FLI1 and RNF43. Cell proliferation and invasion results showed that mTOR inhibitors (GSK2126458) can inhibit the proliferation of pancreatic cancer cells.

CONCLUSIONS

This study suggested that the PI3K-Akt signaling pathway may be a key pathway for pancreatic cancer, our study uncovered the potential therapeutic potential of GSK2126458, a specific mTOR inhibitor, for pancreatic cancer.

Metabolomics based predictive classifier for early detection of pancreatic ductal adenocarcinoma

The availability of robust classification algorithms for the identification of high risk individuals with resectable disease is critical to improving early detection strategies and ultimately increasing survival rates in PC. We leveraged high quality biospecimens with extensive clinical annotations from patients that received treatment at the Medstar-Georgetown University hospital. We used a high resolution mass spectrometry based global tissue profiling approach in conjunction with multivariate analysis for developing a classification algorithm that would predict early stage PC with high accuracy. The candidate biomarkers were annotated using tandem mass spectrometry. We delineated a six metabolite panel that could discriminate early stage PDAC from benign pancreatic disease with >95% accuracy of classification (Specificity = 0.85, Sensitivity = 0.9). Subsequently, we used multiple reaction monitoring mass spectrometry for evaluation of this panel in plasma samples obtained from the same patients. The pattern of expression of these metabolites in plasma was found to be discordant as compared to that in tissue. Taken together, our results show the value of using a metabolomics approach for developing highly predictive panels for classification of early stage PDAC. Future investigations will likely lead to the development of validated biomarker panels with potential for clinical translation in conjunction with CA-19-9 and/or other biomarkers.

A mixed treatment comparison of toxicity of gemcitabine combined with different targeted drugs in the treatment of advanced or metastatic pancreatic cancer

The mixed treatment comparison study was performed in order to compare the toxicities of Gemcitabine and different targeted drug combinations in the treatment of advanced/metastatic pancreatic cancer (PC). Searches were performed from the inception of PubMed and Cochrane Library databases to February 2017. This study included randomized controlled trials (RCTs) of Gemcitabine and different targeted drug combinations in the treatment of advanced/metastatic PC. Odds ratio (OR) values were calculated by direct and indirect comparisons, and the surface under the cumulative ranking curves (SUCRA) were drawn. A total of six RCTs were finally incorporated into the study. These studies included six therapy regimens: Gemcitabine + Axitinib, Gemcitabine + Trametinib, Gemcitabine + Sorafenib, Gemcitabine + Bevacizumab, Gemcitabine + Erlotinib and Gemcitabine + Tipifarnib. The results showed that Gemcitabine + Axitinib combinations showed lower incidence rates of rashes (all grades) in comparison to Gemcitabine + Trametinib and Gemcitabine + Erlotinib combinations. Compared with Gemcitabine+ Trametinib combinations, Gemcitabine + Axitinib combinations showed lower incidence rates of diarrhea (grade ≥ 3). Moreover, the cluster analyses results revealed that Gemcitabine + Axitinib combinations and Gemcitabine + Sorafenib combinations showed lower incidence rates of hematotoxicity, while Gemcitabine + Axitinib combinations showed lower incidence rates of non-hematotoxicity. Collectively, the data provided strong evidence of Gemcitabine + Axitinib combinations showing lower incidence rates of non-hematotoxicity, and Gemcitabine + Axitinib and Gemcitabine + Sorafenib combinations may have lower incidence rates of hematotoxicity in the treatment of advanced/metastatic PC.

Toxicity of chemotherapy regimens in advanced and metastatic pancreatic cancer therapy: A network meta-analysis

This network meta-analysis is adopted in order to compare the toxicity of different chemotherapy regimens in the treatment of advanced/metastatic pancreatic cancer (PC). Randomized controlled trials (RCTs) about different chemotherapy regimens for advanced/metastatic PC were included in this network meta-analysis using Cochrane Library and PubMed electronic databases. The network meta-analysis was performed to combine direct and indirect evidence in order to calculate the odd ratios (OR) and draw a surface under the cumulative ranking (SUCRA) curve. A total of 19 RCTs were enrolled in this network meta-analysis including 12 chemotherapy regimens (Gemcitabine, Gemcitabine + S-1 [tegafur], Gemcitabine + nab-paclitaxel, Gemcitabine + Capecitabine, Gemcitabine + Cisplatin, FOLFIRINOX [oxaliplatin + irinotecan + fluorouracil + leucovorin], Gemcitabine + oxaliplatin, Gemcitabine + irinotecan, Gemcitabine + Exatecan, Gemcitabine + pemetrexed, Gemcitabine + 5-FU, S-1). The incidence of anemia of Gemcitabine + Capecitabine regimen was higher compared with Gemcitabine regimen, Gemcitabine + pemetrexed regimen exhibited the highest incidence rates of anemia and neutropenia; while Gemcitabine + S-1, Gemcitabine + Cisplatin and FOLFIRINOX regimens exhibited the highest incidence rates of neutropenia. However, S-1 regimen exhibited lower incidence rates of leukopenia and thrombocytopenia. Moreover, the incidence rates of nausea/vomiting and rash of Gemcitabine + S-1 regimen were higher compared with Gemcitabine regimen, while Gemcitabine + Cisplatin regimen had the highest incidence rate of nausea/vomiting. This study demonstrated that the hematologic toxicity of S-1 regimen was the lowest, while Gemcitabine regimen exhibited the lowest incidence rate of non-hematologic toxicity, providing guidance for the treatment of advanced/metastatic PC.

An Efficient Synthesis of Angelmarin and its Analogs

Angelmarin, a naturally occurring coumarin, exhibited highly anti-austerity potency towards human pancreatic carcinoma cell line PANC-1. In this paper, an efficient and eco-friendly synthesis of angelmarin and its analogs from columbianetin has been developed via a ZnO mediated esterification and a Wittig reaction.

Metabolomic biomarkers of pancreatic cancer: a meta-analysis study

Pancreatic cancer (PC) is an aggressive disease with high mortality rates, however, there is no blood test for early detection and diagnosis of this disease. Several research groups have reported on metabolomics based clinical investigations to identify biomarkers of PC, however there is a lack of a centralized metabolite biomarker repository that can be used for meta-analysis and biomarker validation. Furthermore, since the incidence of PC is associated with metabolic syndrome and Type 2 diabetes mellitus (T2DM), there is a need to uncouple these common metabolic dysregulations that may otherwise diminish the clinical utility of metabolomic biosignatures. Here, we attempted to externally replicate proposed metabolite biomarkers of PC reported by several other groups in an independent group of PC subjects. Our study design included a T2DM cohort that was used as a non-cancer control and a separate cohort diagnosed with colorectal cancer (CRC), as a cancer disease control to eliminate possible generic biomarkers of cancer. We used targeted mass spectrometry for quantitation of literature-curated metabolite markers and identified a biomarker panel that discriminates between normal controls (NC) and PC patients with high accuracy. Further evaluation of our model with CRC, however, showed a drop in specificity for the PC biomarker panel. Taken together, our study underscores the need for a more robust study design for cancer biomarker studies so as to maximize the translational value and clinical implementation.

Efficacy and Toxicity of Different Chemotherapy Regimens in the Treatment of Advanced or Metastatic Pancreatic Cancer: A Network Meta-Analysis

Objective A network meta-analysis was conducted to compare the efficacy and toxicity of different chemotherapy regimens in treating advanced or metastatic pancreatic cancer (PC). PubMed, Cochrane Library and EMBASE databases from inception to June 2016 were searched. A combination of direct and indirect evidences was referred to for calculating the weighted mean difference (WMD) or the odds ratio (OR) and to establish surface under the cumulative ranking (SUCRA) curves, so as to evaluate the efficacy and toxicity of different chemotherapy regimens in treating advanced or metastatic PC. Twenty randomized controlled trials were enrolled. Twelve chemotherapy regimens included Gemcitabine, S-1 (Tegafur), Gemcitabine + Cisplatin, Gemcitabine + Capecitabine, Gemcitabine + S-1, Gemcitabine + 5-FU (5-fluorouracil), Gemcitabine + Exatecan, Gemcitabine + Irinotecan, Gemcitabine + Nab-paclitaxel, FOLFIRINOX (Oxaliplatin + Irinotecan + Fluorouracil + Leucovorin), Gemcitabine + Oxaliplatin, and Gemcitabine + Pemetrexed. Higher overall response rate (ORR) was observed in patients treated with the gemcitabine + S-1 and FOLFIRINO regimens. Thrombocytopenia reduced in patients treated with the S-1 regimen. The Gemcitabine + S-1 and FOLFIRINO regimens had better short- and long-term efficacies than the other regimens; S-1 regimen had the lowest hematologic toxicity, while Gemcitabine + Nab-paclitaxel, FOLFIRINOX, and Gemcitabine + Pemetrexed regimens had higher incidence of non-hematologic toxicity among twelve chemotherapy regimens. The efficacy of Gemcitabine + S-1 and FOLFIRINOX regimens may be better in treating patients with advanced or metastatic pancreatic cancer, while FOLFIRINOX and Gemcitabine + Pemetrexed regimens may have relatively higher incidence of toxicity than other regimens. J. Cell. Biochem. 119: 511-523, 2018. © 2017 Wiley Periodicals, Inc.

Chemical Constituents of Mangifera indica and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cell lines such as PANC-1 have an altered metabolism, enabiling them to tolerate and survive under extreme conditions of nutrient starvation. The search for candidates that inhibit their viability during nutrition starvation represents a novel antiausterity strategy in anticancer drug discovery. A methanol extract of the bark of Mangifera indica was found to inhibit the survival of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions with a PC50 value of 15.5 μg/mL, without apparent toxicity, in normal nutrient-rich conditions. Chemical investigation on this bioactive extract led to the isolation of 19 compounds (1-19), including two new cycloartane-type triterpenes, mangiferolate A (1) and mangiferolate B (2). The structures of 1 and 2 were determined by NMR spectroscopic analysis. Among the isolated compounds, mangiferolate B (2) and isoambolic acid (12) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under the nutrition-deprived condition with PC50 values of 11.0 and 4.8 μM, respectively.

Identification of the Factors Responsible for the Selective in vitro Cytotoxic Activity of Isoprenylated Coumarin Derivatives under Nutrient-deprived Conditions

Pancreatic cancer is one of the most devastating forms of human cancer. The lack of effective clinical treatments for pancreatic cancer has led to one of the lowest five-year survival rates among all cancers. Recently, our laboratory has developed a novel series of isoprenylated coumarin derivatives that have exhibited anti-pancreatic cancer activity exclusively under nutrient-deprived conditions. In this study, we report the effect of the various cell culture medium components on the preferential cytotoxicity of our lead isoprenylated coumarin compound against the pancreatic adenocarcinoma cell line PANC-1. In particular, our findings show a clear link between observed cytotoxicity and glucose deprivation, suggesting that our compound targets a salvage pathway when glycolysis is no longer an option for cancer cell survival. The cytotoxicity of our lead compound was also examined in vitro against two other pancreatic cancer cell lines, BxPC-3 and Capan-2 under both nutrient-rich and nutrient-deprived conditions.

Definitive Characterization of CA 19-9 in Resectable Pancreatic Cancer Using a Reference Set of Serum and Plasma Specimens

The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19–9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19–9 in early-stage pancreatic cancer and the control groups. CA 19–9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70–74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19–9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9–9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19–9 data presented here will be useful for benchmarking and for exploring relationships to CA 19–9.

Antitumour indolequinones: synthesis and activity against human pancreatic cancer cells

An important determinant of the growth inhibitory activity of indolequinones against pancreatic cancer cells is substitution on the 2-position with 2-unsubstituted derivatives being markedly more potent. A series of indolequinones bearing a range of substituents on nitrogen and at the indolylcarbinyl position was prepared by copper(II)-mediated reaction of bromoquinones and enamines, followed by functional group interconversions. The compounds were then assayed for their ability to inhibit the growth of pancreatic cancer cells. The pKa of the leaving group at the 3-position was shown to influence growth inhibitory activity that is consistent with the proposed mechanism of action of reduction, loss of leaving group and formation of a reactive iminium species. Substitutions on the indole nitrogen were well tolerated with little influence on growth inhibitory activity while substitutions at the 5- and 6-positions larger than methoxy led to decreased activity. The studies presented define the range of substitutions of 2-unsubstituted indolequinones required for optimal growth inhibitory activity.

Inhibition of arachidonic acid metabolism to decrease pancreatic cancer cell proliferation

AIM: To investigate the effect of inhibition of arachidonic acid metabolism on proliferation of pancreatic cancer cells.

METHODS: Cultured pancreatic cancer SW1990 cells were treated with different concentrations of MK886, celecoxib, or MK886 + celecoxib. After treatment, the expression of leukotriene B4 receptor 1 (BLT1) and vascular endothelial growth factor (VEGF) mRNAs was detected by semi-quantitative RT-PCR and the expression of phosphorylated extracellular regulated protein (p-Erk) was measured by Western blot.

RESULTS: Treatment with MK886 significantly decreased the expression of BLT1 and VEGF mRNAs (P < 0.01 for both) and p-Erk (P < 0.05). Treatment with celecoxib did not alter the expression of BLT1 mRNA and decreased the expression of VEGF mRNA compared with untreated cells (P < 0.01), but increased the expression of p-Erk compared with the MK886 group (P < 0.01). Treatment with MK886 and celecoxib significantly decreased the expression of BLT1 and VEGF mRNAs (P < 0.01 for both), but did not alter the expression of p-Erk.

CONCLUSION: Both two pathways of arachidonic acid metabolism are associated with pancreatic cancer cell proliferation, with the pathway involving 5-lipoxygenase being more important.

Powerful inhibition of experimental human pancreatic cancers by receptor targeted cytotoxic LH-RH analog AEZS-108

Pancreatic carcinoma is one of the cancers with the worse prognosis, thus any therapeutic improvement is imperative. Cytotoxic LH-RH analog, AN-152 (proprietary designation, AEZS-108), consisting of doxorubicin (DOX) conjugated to D-Lys⁶LH-RH, is now in clinical trials for targeted therapy of several sex hormone-dependent tumors that express LH-RH receptors. We investigated LH-RH receptors in human pancreatic carcinoma and the effects of AN-152 (AEZS-108) on experimental pancreatic cancers. We determined LH-RH receptor presence in human pancreatic cancer samples by immunohistochemistry and, in three human pancreatic cancer lines (SW-1990, Panc-1 and CFPAC-1), by binding assays and Western blotting. The effects of the cytotoxic LH-RH analog were investigated on growth of these same cancer lines xenografted into nude mice. We also analyzed differences between the antitumor effects of the cytotoxic analog and its cytotoxic radical alone, doxorubicin (DOX), on the expression of cancer-related genes by PCR arrays. LH-RH receptors were expressed in two randomly selected surgically removed human pancreatic cancer samples and in all three cancer lines. Cytotoxic LH-RH analogs powerfully inhibited growth of all three tumor lines in nude mice; AN-152 was significantly stronger than DOX on Panc-1 and CFPAC-1 cancers. PCR array showed that cytotoxic LH-RH analog AN-152 affected the expression of genes associated with cellular migration, invasion, metastasis and angiogenesis more favorably than DOX, however the changes in gene expression varied considerably among the three cancer lines. Cytotoxic LH-RH analog, AEZS-108, may be a useful agent for the treatment of LH-RH receptor positive advanced pancreatic carcinoma.

(+)-Grandifloracin, an antiausterity agent, induces autophagic PANC-1 pancreatic cancer cell death

Human pancreatic tumors are known to be highly resistant to nutrient starvation, and this prolongs their survival in the hypovascular (austere) tumor microenvironment. Agents that retard this tolerance to nutrient starvation represent a novel antiausterity strategy in anticancer drug discovery. (+)-Grandifloracin (GF), isolated from Uvaria dac, has shown preferential toxicity to PANC-1 human pancreatic cancer cells under nutrient starvation, with a PC₅₀ value of 14.5 μM. However, the underlying mechanism is not clear. In this study, GF was found to preferentially induce PANC-1 cell death in a nutrient-deprived medium via hyperactivation of autophagy, as evidenced by a dramatic upregulation of microtubule-associated protein 1 light chain 3. No change was observed in expression of the caspase-3 and Bcl-2 apoptosis marker proteins. GF was also found to strongly inhibit the activation of Akt, a key regulator of cancer cell survival and proliferation. Because pancreatic tumors are highly resistant to current therapies that induce apoptosis, the alternative cell death mechanism exhibited by GF provides a novel therapeutic insight into antiausterity drug candidates.

Selective inhibition of pancreatic ductal adenocarcinoma cell growth by the mitotic MPS1 kinase inhibitor NMS-P715

Most solid tumors, including pancreatic ductal adenocarcinoma (PDAC), exhibit structural and numerical chromosome instability (CIN). Although often implicated as a driver of tumor progression and drug resistance, CIN also reduces cell fitness and poses a vulnerability that can be exploited therapeutically. The spindle assembly checkpoint (SAC) ensures correct chromosome-microtubule attachment, thereby minimizing chromosome segregation errors. Many tumors exhibit upregulation of SAC components such as MPS1, which may help contain CIN within survivable limits. Prior studies showed that MPS1 inhibition with the small molecule NMS-P715 limits tumor growth in xenograft models. In cancer cell lines, NMS-P715 causes cell death associated with impaired SAC function and increased chromosome missegregation. Although normal cells appeared more resistant, effects on stem cells, which are the dose-limiting toxicity of most chemotherapeutics, were not examined. Elevated expression of 70 genes (CIN70), including MPS1, provides a surrogate measure of CIN and predicts poor patient survival in multiple tumor types. Our new findings show that the degree of CIN70 upregulation varies considerably among PDAC tumors, with higher CIN70 gene expression predictive of poor outcome. We identified a 25 gene subset (PDAC CIN25) whose overexpression was most strongly correlated with poor survival and included MPS1. In vitro, growth of human and murine PDAC cells is inhibited by NMS-P715 treatment, whereas adipose-derived human mesenchymal stem cells are relatively resistant and maintain chromosome stability upon exposure to NMS-P715. These studies suggest that NMS-P715 could have a favorable therapeutic index and warrant further investigation of MPS1 inhibition as a new PDAC treatment strategy.

Frizzled-2: A potential novel target for molecular pancreatic cancer therapy

In the present study, pancreatic cancer cell proliferation was analyzed following the suppression of frizzled (Fz)2 expression. Reverse transcription polymerase chain reaction (PCR) was performed using RNA isolated from pancreatic cancer cell lines, PANC-1, NOR-P1, PK-45H, PK-1, PK-59, MIA-Paca2 and KP4. A surgical specimen of pancreatic cancer was immunostained with antibodies specific to Fz2. Cell proliferation assays were performed with MIA-Paca2 cells transfected with small interfering RNA (siRNA) or short hairpin RNA (shRNA) of Fz2. Fz2 was found to be expressed in all pancreatic cancer cell lines, with the exception of NOR-P1. Immunostaining revealed that Fz2 was not expressed in normal pancreatic tissues, while it was expressed in pancreatic cancer cells. The expression levels of cyclin D1 were analyzed by quantitative PCR. The proliferation and expression of cyclin D1 were suppressed with the siRNA and shRNA of Fz2 in the MIA-Paca2 cells. Therefore, Fz2 is a potential target for the molecular therapy of pancreatic cancer.

Multimodal Treatment Eliminates Cancer Stem Cells and Leads to Long-Term Survival in Primary Human Pancreatic Cancer Tissue Xenografts

Purpose

In spite of intense research efforts, pancreatic ductal adenocarcinoma remains one of the most deadly malignancies in the world. We and others have previously identified a subpopulation of pancreatic cancer stem cells within the tumor as a critical therapeutic target and additionally shown that the tumor stroma represents not only a restrictive barrier for successful drug delivery, but also serves as a paracrine niche for cancer stem cells. Therefore, we embarked on a large-scale investigation on the effects of combining chemotherapy, hedgehog pathway inhibition, and mTOR inhibition in a preclinical mouse model of pancreatic cancer.

Experimental Design

Prospective and randomized testing in a set of almost 200 subcutaneous and orthotopic implanted whole-tissue primary human tumor xenografts.

Results

The combined targeting of highly chemoresistant cancer stem cells as well as their more differentiated progenies, together with abrogation of the tumor microenvironment by targeting the stroma and enhancing tissue penetration of the chemotherapeutic agent translated into significantly prolonged survival in preclinical models of human pancreatic cancer. Most pronounced therapeutic effects were observed in gemcitabine-resistant patient-derived tumors. Intriguingly, the proposed triple therapy approach could be further enhanced by using a PEGylated formulation of gemcitabine, which significantly increased its bioavailability and tissue penetration, resulting in a further improved overall outcome.

Conclusions

This multimodal therapeutic strategy should be further explored in the clinical setting as its success may eventually improve the poor prognosis of patients with pancreatic ductal adenocarcinoma.

Biological Studies of Turmeric Oil, Part 2: Isolation and Characterization of Turmeric Oil Components; Cytotoxic Activity against Pancreatic Cancer Cells

The current study is directed at identifying compounds that have biological activity in the less studied oil fraction of Curcuma longa (turmeric) to treat pancreatic cancer, which has no good treatment options. Fractional distillation and chromatographic separation of turmeric oil (TO) gave column fractions (CF) having biological activity against the PANC-1 pancreatic cancer cell line, with an EC50 in the range of 23 to 33 μg/mL. These fractions were analyzed by NMR and GCMS and found to contain the sesquiterpenes, ar-curcumene, 7-epi-zingiberene, β-sesquiphellandrene, curlone, α-turmerone, β-turmerone and ar-turmerone. The ability of TO components to induce cell death was independent of caspase activity. Potency was higher at lower cell density and was reduced by increasing serum concentration, the latter indicating serum binding of active components.

Inhibition of the mitochondrial Hsp90 chaperone network: a novel, efficient treatment strategy for cancer?

Research has shown that cancer cells exhibit multiple deregulated pathways, involving proliferation, migration and cell death. Heat-shock-proteins have evolved as "central regulators" and are implicated in the modulation of these pathways and in organelle-specific signaling. In this instance, heat-shock-proteins (Hsps) assist cancer cells in the maturation of proteins. Hsp90 is of particular interest because its enzymatic ATPase activity is elevated in malignant cells as compared to non-neoplastic counterparts. Consistent with its high-activity in cancer cells, Hsp90 stabilizes a considerable number of proteins being instrumental in carcinogenesis and the maintenance and growth of highly malignant cancers. Among its distribution Hsp90 is also localized within mitochondria of neoplastic cells of various origin, interacting with another chaperone, TRAP1 (Tumor necrosis factor type 1 receptor-associated protein or Heat-shock-protein 75) to antagonize the cell death promoting properties of the matrix protein, Cyclophilin-D. Several preclinical studies, including in vivo studies in both orthotopic and genetic animal models, have confirmed that targeting mitochondrial Hsp90 may be a novel efficient treatment method for highly recalcitrant tumors. This review summarizes the most recent findings of mitochondrial Hsp90 signaling and its potential implications for cancer therapy.

Metronomic ceramide analogs inhibit angiogenesis in pancreatic cancer through up-regulation of caveolin-1 and thrombospondin-1 and down-regulation of cyclin D1

AIMS

To evaluate the antitumor and antiangiogenic activity of metronomic ceramide analogs and their relevant molecular mechanisms.

METHODS

Human endothelial cells [human dermal microvascular endothelial cells and human umbilical vascular endothelial cell (HUVEC)] and pancreatic cancer cells (Capan-1 and MIA PaCa-2) were treated with the ceramide analogs (C2, AL6, C6, and C8), at low concentrations for 144 hours to evaluate any antiproliferative and proapoptotic effects and inhibition of migration and to measure the expression of caveolin-1 (CAV-1) and thrombospondin-1 (TSP-1) mRNAs by real-time reverse transcription-polymerase chain reaction. Assessment of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and Akt phosphorylation and of CAV-1 and cyclin D1 protein expression was performed by ELISA. Maximum tolerated dose (MTD) gemcitabine was compared against metronomic doses of the ceramide analogs by evaluating the inhibition of MIA PaCa-2 subcutaneous tumor growth in nude mice.

RESULTS

Metronomic ceramide analogs preferentially inhibited cell proliferation and enhanced apoptosis in endothelial cells. Low concentrations of AL6 and C2 caused a significant inhibition of HUVEC migration. ERK1/2 and Akt phosphorylation were significantly decreased after metronomic ceramide analog treatment. Such treatment caused the overexpression of CAV-1 and TSP-1 mRNAs and proteins in endothelial cells, whereas cyclin D1 protein levels were reduced. The antiangiogenic and antitumor impact in vivo of metronomic C2 and AL6 regimens was similar to that caused by MTD gemcitabine.

CONCLUSIONS

Metronomic C2 and AL6 analogs have antitumor and antiangiogenic activity, determining the up-regulation of CAV-1 and TSP-1 and the suppression of cyclin D1.

Preclinical evaluation of anticancer efficacy and pharmacological properties of FBA-TPQ, a novel synthetic makaluvamine analog

We have recently designed and synthesized a novel iminoquinone anticancer agent, 7-(4-fluorobenzylamino)-1,3,4,8-tetrahydropyrrolo[4,3,2-de]quinolin-8(1H)-one (FBA-TPQ) and initiated its preclinical development. Herein we investigated its efficacy, safety, and pharmacokinetics in in vitro and in vivo models of human pancreatic cancer. Our results demonstrated that FBA-TPQ inhibited pancreatic cancer cell growth, induced apoptosis, and caused cell cycle arrest in vitro. It inhibited the growth of xenograft tumors with minimal host toxicity. To facilitate future preclinical and clinical development of the agent, we also developed and validated a Rapid Resolution Liquid Chromatography (RRLC) method for quantitative analysis of FBA-TPQ in plasma and tissue samples. The method was found to be precise, accurate, and specific. Using this method, we carried out in vitro and in vivo evaluations of the pharmacological properties of FBA-TPQ, including stability in plasma, plasma protein binding, metabolism by S9 enzymes, plasma pharmacokinetics, and tissue distribution. Our results indicate that FBA-TPQ is a potential therapeutic agent for pancreatic cancer, providing a basis for future preclinical and clinical development.

Pancreatic stellate cells form a niche for cancer stem cells and promote their self-renewal and invasiveness

Chronic pancreatitis and pancreatic ductal adenocarcinoma (PDAC) are characterized by extensive fibrosis. Importantly, in PDAC, this results in poor vascularization and impaired drug delivery to the cancer cells. Therefore, the combined targeting of pancreatic tumor stroma and chemotherapy should enhance response rates, but the negative outcome of a recent phase III clinical trial for the combination of chemotherapy and hedgehog pathway inhibition suggests that other means also need to be considered. Emerging data indicate that elimination of cancer stem cells as the root of the cancer is of pivotal importance for efficient treatment of pancreatic cancer. Recently, we demonstrated in a highly relevant preclinical mouse model for primary pancreatic cancers that the combination of cancer stem cell-targeting strategies in combination with a stroma-targeting agent, such as a hedgehog pathway inhibitor and chemotherapy, results in significantly enhanced long-term and progression-free survival. In the present study, we demonstrate mechanistically that Nodal-expressing pancreatic stellate cells are an important component of the tumor stroma for creating a paracrine niche for pancreatic cancer stem cells. Secretion of the embryonic morphogens Nodal/Activin by pancreatic stellate cells promoted in vitro sphere formation and invasiveness of pancreatic cancer stem cells in an Alk4-dependent manner. These data imply that the pancreatic cancer stem cell phenotype is promoted by paracrine Nodal/Activin signaling at the tumor-stroma interface. Therefore, targeting the tumor microenvironment is not only able to improve drug delivery but, even more importantly, destroys the cancer stem cell niche and, therefore, should be an integral part of cancer stem cell-based treatment strategies.