Do hENT1 and RRM1 predict the clinical benefit of gemcitabine in pancreatic cancer?

Baseline splenic volume as a surrogate marker of FOLFIRINOX efficacy in advanced pancreatic carcinoma

Background

The FOLFIRINOX regimen is the standard first-line treatment for advanced pancreatic adenocarcinoma (aPDAC). However, because of its potential toxicity, predictive biomarkers could help clinical decision-making.

Methods

A cohort of 97 aPDAC patients treated with first-line FOLFIRINOX were studied. The association between splenic volume and progression-free survival (PFS) and overall survival (OS) was evaluated using univariate and multivariable Cox analyses. The external validation cohort was composed of 117 patients treated with Gemcitabine and 52 patients treated with FOLFIRINOX.

Results

In the training cohort, the splenic volume of 97 patients was measured at baseline and at the end of therapy. The spleen size increased in 81% of patients, with at least a 50% increase in 27% of patients. Baseline splenomegaly predicted PFS (HR 1.812, 95% CI = [1.036–3.169]; p = 0.03) and OS (HR 1.983, 95% CI = [1.085–3.624]; p = 0.02) in the training cohort. These results were then validated in an external cohort of patients who were treated with FOLFIRINOX excluding those in the control cohort who were treated with gemcitabine. In a multivariate model based on the CoxBoost method, the following were selected as predictive markers of FOLFIRINOX efficacy (AUC = 0.81): performance status, liver metastasis, baseline Ca199 and CEA levels and baseline splenomegaly. The predictive ability of the model was validated in the external cohort that was also treated with FOLFIRINOX.

Conclusions

Baseline splenomegaly is a predictive marker of a poor response to FOLFIRINOX in aPDAC and remained predictive when associated with other clinical variables.

Locally Advanced or Metastatic Pancreatic Adenocarcinoma: Easily Available Factors of Predictive Prolonged Survival Under Gemcitabine

BACKGROUND

Prognosis of patients with locally advanced or metastatic pancreatic adenocarcinoma is poor. In this study, we assessed the predictive value of easily available baseline factors for prolonged survival.

PATIENTS AND METHODS

We conducted a retrospective study on patients who received gemcitabine between 1999 and 2010 for locally advanced or metastatic pancreatic adenocarcinoma. The primary end-point was the 12-month survival rate.

RESULTS

We included 195 patients. The median age was 62.9 years; the performance status was 0-1 in 80 and 2-3 in 92 patients. The median number of metastatic sites was one. A total of 73 patients (37.4%) were alive 12 months after beginning chemotherapy. In multivariate analysis, no liver metastasis, CA19-9 level <250 IU/ml and localized or locally advanced cancer at diagnosis were good prognostic factors. According to a clinical score based on these features, overall survival was 7.7, 13.5, 19.7 and 21.0 months, respectively (p<0.001).

CONCLUSION

We identified easily available prognostic factors for prolonged survival in patients treated with gemcitabine.

MiR-608 regulating the expression of ribonucleotide reductase M1 and cytidine deaminase is repressed through induced gemcitabine chemoresistance in pancreatic cancer cells

PURPOSE

Gemcitabine resistance is the main problem in pancreatic adenocarcinoma patients. Hence, we aimed to identify the correlation between expression of RRM1 and CDA as the resistance genes and their predicted targeting miR-608 in the resistant pancreatic cancer cell lines to gemcitabine.

METHODS

Dual luciferase assay was performed to determine whether both RRM1 and CDA are targeted by miR-608 in 293T and pancreatic cancer cell lines. AsPC-1 and MIA PaCa-2 cell lines became gradually resistant to gemcitabine by exposing to the increasing doses of gemcitabine. After RNA and miRNAs extraction and cDNA conversion, the expressions of RRM1, CDA and miR-608 in all cell lines were studied by quantitative PCR. Pre-miR-608 transfection to the cell lines was done by calcium phosphate method. MTT assay was performed for analyzing the chemo sensitivity of different cell lines to gemcitabine.

RESULTS

Luciferase assays showed that miR-608 targeted RRM1 and CDA genes in 293T, AsPC-1 and MIA PaCa-2 cell lines. Compared to parental cell line, resistant MIA PaCa-2 and AsPC-1 cells demonstrated increased expression of RRM1 and CDA. On the other hand the expression of miR-608 in resistant MIA PaCa-2 and AsPC-1 cells was lower than parental cells. Furthermore, transfection of MIA PaCa-2 and AsPC-1 cells by miR-608 lead to decreased expression of RRM1 and CDA and lowered viability of the cells in comparison with scrambled microRNA transfected cells.

CONCLUSION

During resistance induction in pancreatic cancer cells, miR-608 which is targeting RRM1 and CDA is downregulated which leads to upregulation of these genes.

Future role of endoscopic ultrasound in personalized management of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is aggressive and lethal with the majority of cases presenting with advanced unresectable disease due to delayed diagnosis. Despite improvement in surgery, chemotherapies, and intensive care medicine, the outcome of PDAC remains poor, which may relate to the tumor biology. Recent data suggest that PDAC is a "systemic cancer" with complex molecular or genomics derangement with marked heterogeneity. The ability to characterize the PDAC better by detailed evaluation of tissue biomarkers or genomics allows for improved prediction of prognosis and stratification of treatment, a concept known as "personalized cancer therapy." Using tissue from resected PDAC specimens has several weaknesses and is only possible in 20% of patients with PDAC. Endoscopic ultrasound (EUS)-guided biopsy overcomes these weaknesses, and with recent advancements in needle technology, tissue can be obtained for personalized cancer therapy for all patients with PDAC. This review aims to outline our current understanding of the molecular biology of PDAC specifically focusing on how EUS-guided biopsy may play a fundamental role in tissue acquisition, allowing for assessment and stratify therapy according to the individual cancer biology as we move toward the era of precision medicine.

Astaxanthin inhibits gemcitabine-resistant human pancreatic cancer progression through EMT inhibition and gemcitabine resensitization

Pancreatic cancer rapidly acquires resistance to chemotherapy resulting in its being difficult to treat. Gemcitabine is the current clinical chemotherapy strategy; however, owing to gemcitabine resistance, it is only able to prolong the life of patients with pancreatic cancer for a limited number of months. Understanding the underlying molecular mechanisms of gemcitabine resistance and selecting a suitable combination of agents for the treatment of pancreatic cancer is required. Astaxanthin (ASX) is able to resensitize gemcitabine-resistant human pancreatic cancer cells (GR-HPCCs) to gemcitabine. ASX was identified to upregulate human equilibrative nucleoside transporter 1 (hENT1) and downregulate ribonucleoside diphosphate reductase (RRM) 1 and 2 to enhance gemcitabine-induced cell death in GR-HPCCs treated with gemcitabine, and also downregulates TWIST1 and ZEB1 to inhibit the gemcitabine-induced epithelial-mesenchymal transition (EMT) phenotype in GR-HPCCs and to mediate hENT1, RRM1 and RRM2. Furthermore, ASX acts through the hypoxia-inducible factor 1α/signal transducer and activator of transcription 3 signaling pathway to mediate TWIST1, ZEB1, hENT1, RRM1 and RRM2, regulating the gemcitabine-induced EMT phenotype and gemcitabine-induced cell death. Co-treatment with ASX and gemcitabine in a tumor xenograft model induced by GR-HPCCs supported the in vitro results. The results of the present study provide a novel therapeutic strategy for the treatment of gemcitabine-resistant pancreatic cancer.

Enhancing Drug Efficacy and Therapeutic Index through Cheminformatics-Based Selection of Small Molecule Binary Weapons That Improve Transporter-Mediated Targeting: A Cytotoxicity System Based on Gemcitabine

The transport of drug molecules is mainly determined by the distribution of influx and efflux transporters for which they are substrates. To enable tissue targeting, we sought to develop the idea that we might affect the transporter-mediated disposition of small-molecule drugs via the addition of a second small molecule that of itself had no inhibitory pharmacological effect but that influenced the expression of transporters for the primary drug. We refer to this as a “binary weapon” strategy. The experimental system tested the ability of a molecule that on its own had no cytotoxic effect to increase the toxicity of the nucleoside analog gemcitabine to Panc1 pancreatic cancer cells. An initial phenotypic screen of a 500-member polar drug (fragment) library yielded three “hits.” The structures of 20 of the other 2,000 members of this library suite had a Tanimoto similarity greater than 0.7 to those of the initial hits, and each was itself a hit (the cheminformatics thus providing for a massive enrichment). We chose the top six representatives for further study. They fell into three clusters whose members bore reasonable structural similarities to each other (two were in fact isomers), lending strength to the self-consistency of both our conceptual and experimental strategies. Existing literature had suggested that indole-3-carbinol might play a similar role to that of our fragments, but in our hands it was without effect; nor was it structurally similar to any of our hits. As there was no evidence that the fragments could affect toxicity directly, we looked for effects on transporter transcript levels. In our hands, only the ENT1-3 uptake and ABCC2,3,4,5, and 10 efflux transporters displayed measurable transcripts in Panc1 cultures, along with a ribonucleoside reductase RRM1 known to affect gemcitabine toxicity. Very strikingly, the addition of gemcitabine alone increased the expression of the transcript for ABCC2 (MRP2) by more than 12-fold, and that of RRM1 by more than fourfold, and each of the fragment “hits” served to reverse this. However, an inhibitor of ABCC2 was without significant effect, implying that RRM1 was possibly the more significant player. These effects were somewhat selective for Panc cells. It seems, therefore, that while the effects we measured were here mediated more by efflux than influx transporters, and potentially by other means, the binary weapon idea is hereby fully confirmed: it is indeed possible to find molecules that manipulate the expression of transporters that are involved in the bioactivity of a pharmaceutical drug. This opens up an entirely new area, that of chemical genomics-based drug targeting.

Sclareolide enhances gemcitabine‑induced cell death through mediating the NICD and Gli1 pathways in gemcitabine‑resistant human pancreatic cancer

Pancreatic cancer is a type of cancer, which rapidly develops resistance to chemotherapy. Gemcitabine is the treatment used clinically, however, gemcitabine resistance leads to limited efficacy and patient survival rates of only a few months following diagnosis. The aim of the present study was to investigate the mechanisms underlying gemcitabine resistance in pancreatic cancer and to select targeted agents combined with gemcitabine to promote the treatment of pancreatic cancer. Panc-1 and ASPC-1 human pancreatic cancer cells (HPCCs) were used to establish the experimental model, and HPCCs were exposed to gemcitabine of serially increased concentrations to generate gemcitabine-resistant cells (GR-HPCCs). The anticancer effect of gemcitabine combined with sclareolide was then assessed. Epithelial to mesenchymal transition (EMT), human equilibrative nucleoside transporter 1 (hENT1) and ribonucleoside diphosphate reductase 1 (RRM1) were detected in the HPCCs and GR-HPCCs, and the mechanisms were investigated. Sclareolide resensitized the GR-HPCCs to gemcitabine. The expression levels of hENT1 and RRM1 were lower and higher, respectively, in GR-HPCCs, compared with HPCCs. Sclareolide upregulated hENT1, downregulated RRM1 and inhibited gemcitabine-induced EMT through the TWIST1/Slug pathway in the GR-HPCCs. In addition, sclareolide mediated the NOTCH 1 intracellular cytoplasmic domain (NICD)/glioma-associated oncogene 1 (Gli1) pathway, which triggered TWIST1/Slug-hENT1/RRM1 signaling and resensitized GR-HPCCs to gemcitabine. Finally, sclareolide resensitized GR-HPCCs to gemcitabine through inducing apoptosis; in vivo, the co-administraion of sclareolide and gemcitabine effectively suppressed tumor growth. Sclareolide may be a novel agent in combination with gemcitabine for the treatment of gemcitabine-resistant pancreatic cancer, which resensitizes GR-HPCCs to gemcitabine through mediating NICD and Gli1.

Dilemma of first line regimens in metastatic pancreatic adenocarcinoma

Pancreatic cancer is one of the deadliest cancers, ranking fourth among cancer-related deaths. Despite all the major molecular advances and treatment breakthroughs, mainly targeted therapies, the cornerstone treatment of metastatic pancreatic cancer (mPC) remains cytotoxic chemotherapy. In 2016, more than 40 years after the introduction of gemcitabine in the management of mPC, the best choice for first-line treatment has not yet been fully elucidated. Two main strategies have been adopted to enhance treatment efficacy. The first strategy is based on combining non-cross resistant drugs, while the second option includes the development of newer generations of chemotherapy. More recently, two new regimens, FOLFIRINOX and gemcitabine/nab-paclitaxel (GNP), have both been shown to improve overall survival in comparison with gemcitabine alone, at the cost of increased toxicity. Therefore, the best choice for first line therapy is a matter of debate. For some authors, FOLFIRINOX should be the first choice in patients with an Eastern Cooperative Oncology Group score (0-1) given its lower hazard ratio. However, others do not share this opinion. In this paper, we review the main comparison points between FOLFIRINOX and GNP. We analyze the two pivotal trials to determine the similarities and differences in study design. In addition, we compare the toxicity profile of the two regimens as well as the impact on quality of life. Finally, we present studies revealing real life experiences and review the advantages and disadvantages of possible second-line therapies including their cost effectiveness.

microRNA-218 promotes gemcitabine sensitivity in human pancreatic cancer cells by regulating HMGB1 expression

OBJECTIVE

The purpose of this study was to examine the effect of gemcitabine (GEM) on microRNA-218 (miR-218) expression in human pancreatic cancer cells.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to examine the differences in miR-218 expression between the GEM-sensitive BxPC-3 pancreatic cancer cells and GEM-resistant PANC-1 cells. The effect of GEM on the expression of miR-218 in PANC-1 cells was also investigated. PANC-1 cells were transfected either with HMGB1 siRNA to knock down the expression of HMGB1 or with the recombinant HMGB1 expression vector (pcDNA3.1-HMGB1) to overexpress HMGB1. The effect of ectopic expression of HMGB1 on the apoptosis of miR-218-transfected and GEM-treated PANC-1 cells was examined by flow cytometric analysis.

RESULTS

The miR-218 expression level was lower in GEM-resistant PANC-1 cells compared to GEM-sensitive BxPC-3 cells (P<0.05). The percentage of apoptotic PANC-1 cells was significantly increased in the miR-218 mimic + GEM group compared to the mimic ctrl + GEM group and the normal control group (P<0.01). The HMGB1 expression level was markedly decreased in PANC-1 cells transfected with HMGB1 siRNA but was significantly increased in PANC-1 cells transfected with the recombinant HMGB1 expression vector, pcDNA3.1-HMGB1 (P<0.01). The proportion of apoptotic PANC-1 cells was significantly lower in the miR-218 mimic + GEM + pcDNA3.1-HMGB1 group compared to the miR-218 mimic + GEM + HMGB1 siRNA group (P<0.01).

CONCLUSIONS

The expression level of miR-218 was downregulated in the GEM-resistant cell line. miR-218 promoted the sensitivity of PANC-1 cells to GEM, which was achieved mainly through regulating the expression of HMGB1 in PANC-1 cells.

How drugs get into cells: tested and testable predictions to help discriminate between transporter-mediated uptake and lipoidal bilayer diffusion

One approach to experimental science involves creating hypotheses, then testing them by varying one or more independent variables, and assessing the effects of this variation on the processes of interest. We use this strategy to compare the intellectual status and available evidence for two models or views of mechanisms of transmembrane drug transport into intact biological cells. One (BDII) asserts that lipoidal phospholipid Bilayer Diffusion Is Important, while a second (PBIN) proposes that in normal intact cells Phospholipid Bilayer diffusion Is Negligible (i.e., may be neglected quantitatively), because evolution selected against it, and with transmembrane drug transport being effected by genetically encoded proteinaceous carriers or pores, whose “natural” biological roles, and substrates are based in intermediary metabolism. Despite a recent review elsewhere, we can find no evidence able to support BDII as we can find no experiments in intact cells in which phospholipid bilayer diffusion was either varied independently or measured directly (although there are many papers where it was inferred by seeing a covariation of other dependent variables). By contrast, we find an abundance of evidence showing cases in which changes in the activities of named and genetically identified transporters led to measurable changes in the rate or extent of drug uptake. PBIN also has considerable predictive power, and accounts readily for the large differences in drug uptake between tissues, cells and species, in accounting for the metabolite-likeness of marketed drugs, in pharmacogenomics, and in providing a straightforward explanation for the late-stage appearance of toxicity and of lack of efficacy during drug discovery programmes despite macroscopically adequate pharmacokinetics. Consequently, the view that Phospholipid Bilayer diffusion Is Negligible (PBIN) provides a starting hypothesis for assessing cellular drug uptake that is much better supported by the available evidence, and is both more productive and more predictive.

Translational research in pancreatic ductal adenocarcinoma: current evidence and future concepts

Pancreatic ductal adenocarcinoma (PDA) is one of the major causes for cancer death worldwide. Treatment of metastatic disease remains challenging as only certain patients benefit from advances made with the intensified chemotherapy regimen folinic acid, irinotecan and oxaliplatin, the epidermal growth factor receptor inhibitor erlotinib or the recently FDA-approved nab-paclitaxel. Up to date, no established approach for prediction of treatment response or specific treatment allocation exists. Translational research was able to identify a number of potential biomarkers that might help to improve the dismal prognosis of PDA by facilitating upfront treatment allocation. This topic highlight is focused on current evidence on potential biomarkers for tumor biology, prognosis and prediction of treatment efficacy.