Gemcitabine based combination chemotherapy in advanced pancreatic cancer-indirect comparison

Selenium Induces Pancreatic Cancer Cell Death Alone and in Combination with Gemcitabine

Survival rate for pancreatic cancer remains poor and newer treatments are urgently required. Selenium, an essential trace element, offers protection against several cancer types and has not been explored much against pancreatic cancer specifically in combination with known chemotherapeutic agents. The present study was designed to investigate selenium and Gemcitabine at varying doses alone and in combination in established pancreatic cancer cell lines growing in 2D as well as 3D platforms. Comparison of multi-dimensional synergy of combinations’ (MuSyc) model and highest single agent (HSA) model provided quantitative insights into how much better the combination performed than either compound tested alone in a 2D versus 3D growth of pancreatic cancer cell lines. The outcomes of the study further showed promise in combining selenium and Gemcitabine when evaluated for apoptosis, proliferation, and ENT1 protein expression, specifically in BxPC-3 pancreatic cancer cells in vitro.

Prediction and identification of synergistic compound combinations against pancreatic cancer cells

Resistance to current therapies is common for pancreatic cancer and hence novel treatment options are urgently needed. In this work, we developed and validated a computational method to select synergistic compound combinations based on transcriptomic profiles from both the disease and compound side, combined with a pathway scoring system, which was then validated prospectively by testing 30 compounds (and their combinations) on PANC-1 cells. Some compounds selected as single agents showed lower GI50 values than the standard of care, gemcitabine. Compounds suggested as combination agents with standard therapy gemcitabine based on the best performing scoring system showed on average 2.82-5.18 times higher synergies compared to compounds that were predicted to be active as single agents. Examples of highly synergistic in vitro validated compound pairs include gemcitabine combined with Entinostat, thioridazine, loperamide, scriptaid and Saracatinib. Hence, the computational approach presented here was able to identify synergistic compound combinations against pancreatic cancer cells.

Antifibrotic effects of pentoxifylline improve the efficacy of gemcitabine in human pancreatic tumor xenografts

We investigated the combinatorial effects of pentoxifylline (PTX) on the efficacy of gemcitabine (GEM) in a human pancreatic tumor xenograft model. PTX significantly improved the efficacy of GEM, as shown by a 50% reduction in tumor growth rate at 4 weeks of treatment compared with that in animals given GEM alone. The fluorescent drug doxorubicin (DOX) was used to test whether drug delivery was improved by PTX, contributing to the improved efficacy of GEM. PTX given for 2 weeks prior to giving DOX improved drug distribution by 1.8‐ to 2.2‐fold with no changes in vessel density, suggesting that improvement in drug delivery was not related to the vascular mechanism. Instead, collagen I content in tumor stroma was significantly reduced, as was the expression of alpha‐smooth muscle actin of cancer‐associated fibroblasts and connective tissue growth factor (CTGF) by PTX pretreatment. Overall, our data demonstrated that increased efficacy of GEM by PTX was associated with improved drug delivery to tumor tissue, which may be attributed to decreased expression of CTGF and subsequent reduction in the stromal collagen matrix in the pancreatic ductal adenocarcinoma tumor. These results support the usefulness of PTX in combination with chemotherapy for targeting drug delivery barriers associated with the stromal matrix, which should be further evaluated for clinical development.

Cross-over comparison and new chemotherapy regimens in metastatic pancreatic cancer

Despite decades of research, pancreatic ductal adenocarcinoma (PDAC) is still one of the most lethal malignant diseases with a devastating 5‑year overall survival of only 4–5%. Indeed, long-term survival was not affected by the introduction of new systemic cytotoxic chemotherapies which remain the key cornerstone in the treatment of metastatic PDAC. In the first-line setting, FOLFIRINOX based upon the results of the PRODIGE/ACCORD trial and gemcitabine with albumin-bound paclitaxel (GNP) based upon the MPACT trial have both been approved as therapeutic options for patients with no significant comorbidities and good performance status. As there is no direct comparison between these regimens, the choice in first-line treatment depends on the toxicity profile, patient’s preferences and reimbursability. In the second-line setting, the results of the NAPOLI-1 trial have led to the approval of nanoliposomal irinotecan (nal-iri) in combination with 5‑fluorouracil (5-FU) for the treatment of patients with mPDAC progressing under gemcitabine-based chemotherapy and therefore this regimen is the first to be approved for use in second-line therapy.

Liposomal irinotecan in gemcitabine-refractory metastatic pancreatic cancer: efficacy, safety and place in therapy

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease. The majority of patients are diagnosed with locally advanced or metastatic disease with a prognosis of short months. Therapeutic options are limited and until recently, there was no standard second-line chemotherapy option. Liposomal constructs have been engineered to encapsulate chemotherapy thereby preventing premature metabolism, improving distribution and minimizing toxicity. Favourable preclinical data on liposomal irinotecan and early phase trials, led to a recently published phase III trial of liposomal irinotecan in combination with fluorouracil and folinic acid in patients with metastatic PDAC, who progressed after gemcitabine-based chemotherapy. As a direct result, the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) have approved the use of liposomal irinotecan in this setting. However, first-line treatment options for this disease now include the combination regimen, FOLFIRINOX, in patients with good performance status, and the role of second-line combination treatment with liposomal irinotecan in this setting is unclear. Recent advances have changed the therapeutic landscape, as clinicians are now able to choose a sequential approach to treatment tailored to the individual patient characteristics. This article reviews current treatment options for metastatic PDAC and focuses on the efficacy, safety and place in therapy of liposomal irinotecan.

Meta-analyses of treatment standards for pancreatic cancer

Pancreatic cancer is the most lethal common cancer with an estimated 5-year survival rate of 6-7% (across all stages). The only potential curative therapy is surgical resection in those with localized disease. Adjuvant (postoperative) therapy confers a survival advantage over postoperative observation alone. Neoadjuvant (preoperative) therapy offers the potential to downstage initially unresectable tumors for resection, sterilize resection margins and decrease locoregional recurrence, and identify a subset of patients with aggressive disease for whom surgery will not be beneficial. Induction chemotherapy followed by consolidation chemoradiation is another recommended approach in those with locally advanced disease. For those who cannot be downstaged, cannot tolerate surgery, or were diagnosed with metastatic disease, treatment remains palliative with chemotherapy being a critical component of this approach. Recently, intensive combination chemotherapy has been shown to improve survival rates in comparison to gemcitabine alone in advanced disease. The past few decades have afforded an accumulation of high-level evidence regarding neoadjuvant, adjuvant and palliative therapies in pancreatic cancer. There are numerous reviews discussing recent retrospective studies, prospective studies and randomized controlled trials in each of these areas. However, reviews of optimal and recommended treatment strategies across all stages of pancreatic cancer that focus on the highest levels of hierarchical evidence, such as meta-analyses, are limited. The discussion of novel therapeutics is beyond the scope of this review. However, an extensive and the most current collection of meta-analyses of first-line systemic and locoregional treatment options for all stages of pancreatic cancer to date has been accumulated.

Chemotherapy regimens for advanced pancreatic cancer: a systematic review and network meta-analysis

BACKGROUND

Advanced pancreatic cancer confers poor prognosis and treatment advancement has been slow. Recent randomized clinical trials (RCTs) have demonstrated survival benefits for combination therapy compared to gemcitabine alone. However, the comparative benefits and harms of available combination chemotherapy treatments are not clear. We therefore conducted a systematic review and Bayesian network meta-analysis to assess the comparative safety and efficacy of chemotherapy regimens for the treatment of advanced pancreatic cancer.

METHODS

MEDLINE, PubMed, EMBASE, Cochrane Central Registry of Clinical trials and abstracts from major scientific meetings were searched for RCTs published from 2002 to 2013. Key outcomes were overall survival (OS), progression free survival (PFS), and safety including grade 3-4 febrile neutropenia, neutropenia, vomiting, diarrhea, fatigue and sensory neuropathy. Bayesian network meta-analyses were conducted to calculate survival and safety outcomes using gemcitabine (GEM) as the reference comparator. Effect estimates and 95% credible intervals were calculated for each comparison. Mean ranks and the probability of being best were obtained for each treatment analyzed in the network meta-analysis.

RESULTS

The search identified 23 studies involving 19 different treatment regimens and 9,989 patients. FOLFIRINOX, GEM/cisplatin/epirubicin/5FU (PEFG), GEM/NAB-paclitaxel (NAB-P), GEM/erlotinib+/-bevacizumab, GEM/capecitabine, and GEM/oxaliplatin were associated with statistically significant improvements in OS and PFS relative to gemcitabine alone and several other treatments. They were amongst the top ranked for survival outcomes amongst other treatments included. No significant differences were found for other combination chemotherapy treatments. Effect estimates from indirect comparisons matched closely to estimates derived from pairwise comparisons. Overall, combination therapies had greater risk for evaluated grade 3-4 toxicities over gemcitabine alone.

CONCLUSIONS

In the absence of head-to-head comparisons, we performed a mixed-treatment analysis to achieve high-quality information on the effectiveness and safety of each treatment. This study suggests that some combination therapies may offer greater benefits in the treatment of advanced pancreatic cancer than others. To more fully elucidate the comparative benefits and harms of different combination chemotherapy regimens, rigorously conducted comparative studies, or network meta-analysis of patient-level data are required.

Connexin-26 is a key factor mediating gemcitabine bystander effect

Gemcitabine is a nucleoside analogue with anticancer activity. Inside the cell, it is sequentially phosphorylated to generate the active drug. Phosphorylated nucleoside analogues have been shown to traffic through gap junctions. We investigated the participation of gap junctional intercellular communication (GJIC) as a possible mechanism spreading gemcitabine cytotoxicity in pancreatic tumors. Immunohistochemical analysis of pancreatic cancer biopsies revealed increased connexin 26 (Cx26) content but loss of connexins 32 (Cx32) and 43 (Cx43) expression. Cx26 abundance in neoplastic areas was confirmed by Cx26 mRNA in situ hybridization. Heterogeneity on the expression levels and the localization of Cx26, Cx32, and Cx43 were identified in pancreatic cancer cells and found to be associated with the extent of GJIC, and correlated with gemcitabine bystander cytotoxic effect. The abundance of Cx26 at the contact points in tumoral regions prompted us to study the involvement of Cx26 in the GJIC of gemcitabine toxic metabolites and their influence on the antitumoral effects of gemcitabine. Knockdown of Cx26 led to decreased GJIC and reduced gemcitabine bystander killing whereas overexpression of Cx26 triggered increased GJIC and enhanced the gemcitabine cytotoxic bystander effect. Gemcitabine treatment of mice bearing tumors, with a high GJIC capacity, resulted in a significant delay in tumor progression. Interestingly, gemcitabine administration in mice bearing tumors that overexpress Cx26 triggered a dramatic tumor regression of 50% from the initial volume. This study shows that Cx26 participates in the gap junction-mediated bystander cytoxic effect of gemcitabine and provides evidence that upregulation of Cx26 improves gemcitabine anticancer efficacy.

Modulatory effects of curcumin on multi-drug resistance-associated protein 5 in pancreatic cancer cells

PURPOSE

Chemotherapy of pancreatic cancer often fails due to the development of intrinsic and acquired resistance during drug treatment. Recent studies have suggested that MRP5 conferred resistance to first-line drugs 5-fluorouracil and gemcitabine by active efflux of drugs from the cell. Our aim was to evaluate whether curcumin could reverse this multi-drug resistance by inhibition of MRP5-mediated efflux.

METHODS

MRP5 protein was detected and localized by immunocytochemistry using a monoclonal antibody in MRP5 over-expressing HEK293 (HEK293/MRP5) cells and two pancreatic cancer cell lines PANC-1 and MiaPaCa-2. The cellular accumulation of a specific MRP5 fluorescent substrate 2',7'-Bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) into these cells was measured by flow cytometry and the cell proliferation determined by a 72-h CyQuant assay.

RESULTS

The cellular accumulation of BCECF in HEK293/MRP5 cells and in PANC-1 and MiaPaCa-2 cells was significantly increased by curcumin in a concentration-dependent manner. Curcumin and a MRP5 inhibitor MK571 had no apparent effects on cellular accumulation of BCECF in parental HEK293 cells. In the proliferation assays, curcumin caused a concentration-dependant increase in the sensitivity to the cytotoxic drug 5-fluorouracil in HEK293/MRP5 cells, PANC-1 and MiaPaCa-2 pancreatic cancer cells, but not in parental HEK293 cells.

CONCLUSIONS

Our results suggest that curcumin is an inhibitor of MRP5 and may be useful in the reversal of multi-drug resistance in pancreatic cancer chemotherapy.

Effects of capecitabine and celecoxib in experimental pancreatic cancer

INTRODUCTION

Pancreatic cancer is a major health problem because of its aggressiveness and the lack of effective systemic therapies. The aim of the study was the identification of beneficial properties of combined celecoxib and capecitabine treatment during an experimental pancreatic cancer model.

METHODS

N-nitrosobis (2-oxopropyl)amine (BOP) was used as a tumoral agent for 12 weeks. Celecoxib and capecitabine were administered either as monotherapy or combined 12 weeks after cancer induction for a period of 24 weeks. The presence of well-developed or moderate adenocarcinoma was evaluated in the pancreas. Several markers of stress, such as lipoperoxides, reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GHS-Px) were determined.

RESULTS

BOP induced the presence of pancreatic tumors associated with a rise in lipoperoxides and the reduction of the antioxidant status in the pancreas. The administration of celecoxib and capecitabine reduced the number of animals with tumors (33 and 66%, respectively). This antitumoral effect was associated with a recovery of GSH, SOD and CAT activity in the pancreas of BOP-treated animals. The combined treatment exerted a synergic antitumoral effect and reduced pancreatic oxidative stress.

CONCLUSION

The combined administration of celecoxib and capecitabine exerted a synergistic antitumoral effect and increased the antioxidant status restoration in pancreatic cancer.

Irinotecan plus bolus/infusional 5-Fluorouracil and leucovorin in patients with pretreated advanced pancreatic carcinoma: a multicenter experience of the Gruppo Oncologico Italia Meridionale

BACKGROUND

Patients with advanced pancreatic cancer failing gemcitabine-based first-line chemotherapy are still in relatively good clinical conditions and may still require second-line chemotherapy, which is frequently administered in daily clinical practice given to without solid scientific support.

PATIENTS AND METHODS

A retrospective survey was carried out including 40 patients with stage III or IV gemcitabine-refractory pancreatic carcinoma. Patients received standard FOLFIRI regimen biweekly until progression or unacceptable toxicity. Response evaluation criteria in solid tumors and National Cancer Institute common toxicity criteria were employed respectively for response and toxicity assessment.

RESULTS

Six partial responses (15%) and 14 stabilizations of disease (35%) were recorded for a tumor growth control rate of 50%. The median time to progression was 3.7 (range, 1-6.5 months), and median overall survival was 6 months (range, 2-8.2 months). A stabilization of performance status and a subjective improvement of cancer-related symptoms were recorded in 21 patients (52.5%). No correlation has been found between length of time to progression during first-line chemotherapy and length of that reported in the second-line setting or objective response. Grade 3-4 diarrhea and mucositis was observed in 15% and 10% of cases, respectively.

CONCLUSIONS

Data presented in this article demonstrate that the second-line FOLFIRI regimen are able to induce an objective response in a relatively small fraction of patients with gemcitabine-refractory adenocarcinoma of the pancreas. The use of second-line chemotherapy should be carefully proposed to patients with good performance status or those who had a good response to first-line therapy.

Current status of molecular markers for early detection of sporadic pancreatic cancer

Pancreatic cancer (PC) is a highly lethal malignancy with near 100% mortality. This is in part due to the fact that most patients present with metastatic or locally advanced disease at the time of diagnosis. Significantly, in nearly 95% of PC patients there is neither an associated family history of PC nor of diseases known to be associated with an increased risk of PC. These groups of patients who comprise the bulk of PC cases are termed as "sporadic PC" in contrast to the familial PC cases that comprise only about 5% of all PCs. Given the insidious onset of the malignancy and its extreme resistance to chemo and radiotherapy, an abundance of research in recent years has focused on identifying biomarkers for the early detection of PC, specifically aiming at the sporadic PC cohort. However, while several studies have established that asymptomatic individuals with a positive family history of PC and those with certain heritable syndromes are candidates for PC screening, the role of screening in identifying sporadic PC is still an unsettled question. The present review attempts to assess this critical question by investigating the recent advances made in molecular markers with potential use in the early diagnosis of sporadic PC - the largest cohort of PC cases worldwide. It also outlines a novel yet simple risk factor based stratification system that could be potentially employed by clinicians to identify those individuals who are at an elevated risk for the development of sporadic PC and therefore candidates for screening.

Phase 1 clinical trials in 83 patients with pancreatic cancer: The M. D. Anderson Cancer Center experience

BACKGROUND

The outcomes of patients with pancreatic cancer treated on early phase clinical trials have not been systematically analyzed. The purpose of this study was to report the presenting characteristics and outcomes of patients with locally advanced or metastatic pancreatic cancer treated on phase 1 clinical trials at a single institution.

METHODS

The authors reviewed the records of consecutive patients with metastatic pancreatic cancer who were treated in the Phase I Clinical Trials Program at The University of Texas M. D. Anderson Cancer Center from November 2004 to March 2009. Data recorded and analyzed included survival, response, and disease characteristics.

RESULTS

Eighty-three patients were identified. The median age was 62 years (range, 39-81 years). Of 78 patients evaluable for response, 2 (3%) had a partial response (PR), and 10 (13%) had stable disease (SD) for ≥ 4 months. With a median follow-up for survivors of 3.7 months, the median survival from presentation in the phase 1 clinic was 5.0 months (95% confidence interval [CI], 3.3-6.2). The median overall survival from diagnosis was 22.1 months (95% CI, 17.9-26.5). The median time to treatment failure was 1.5 months (95% CI, 1.3-1.8). Independent factors associated with lower rates of PR/SD were liver metastases (P = .001) and performance status >0 (P = .01). Independent factors associated with shorter survival were liver metastases (P = .007), low calcium level (P = .015), and elevated CEA level (>6 ng/mL) (P = .005).

CONCLUSIONS

Our results suggest that phase 1 clinical trials offer a reasonable therapeutic approach for patients with advanced pancreatic cancer.

Fabrication of gold nanoparticles for targeted therapy in pancreatic cancer

The targeted delivery of a drug should result in enhanced therapeutic efficacy with low to minimal side effects. This is a widely accepted concept, but limited in application due to lack of available technologies and process of validation. Biomedical nanotechnology can play an important role in this respect. Biomedical nanotechnology is a burgeoning field with myriads of opportunities and possibilities for advancing medical science and disease treatment. Cancer nanotechnology (1-100 nm size range) is expected to change the very foundations of cancer treatment, diagnosis and detection. Nanomaterials, especially gold nanoparticles (AuNPs) have unique physico-chemical properties, such as ultra small size, large surface area to mass ratio, and high surface reactivity, presence of surface plasmon resonance (SPR) bands, biocompatibility and ease of surface functionalization. In this review, we will discuss how the unique physico-chemical properties of gold nanoparticles may be utilized for targeted drug delivery in pancreatic cancer leading to increased efficacy of traditional chemotherapeutics.

Masitinib combined with standard gemcitabine chemotherapy: in vitro and in vivo studies in human pancreatic tumour cell lines and ectopic mouse model

BACKGROUND

Tyrosine kinases are attractive targets for pancreatic cancer therapy because several are over-expressed, including PDGFRalpha/beta, FAK, Src and Lyn. A critical role of mast cells in the development of pancreatic cancer has also been reported. Masitinib is a tyrosine kinase inhibitor that selectively targets c-Kit, PDGFRalpha/beta, Lyn, and to a lesser extent the FAK pathway, without inhibiting kinases of known toxicities. Masitinib is particularly efficient in controlling the proliferation, differentiation and degranulation of mast cells. This study evaluates the therapeutic potential of masitinib in pancreatic cancer, as a single agent and in combination with gemcitabine.

METHODOLOGY/FINDINGS

Proof-of-concept studies were performed in vitro on human pancreatic tumour cell lines and then in vivo using a mouse model of human pancreatic cancer. Molecular mechanisms were investigated via gene expression profiling. Masitinib as a single agent had no significant antiproliferative activity while the masitinib/gemcitabine combination showed synergy in vitro on proliferation of gemcitabine-refractory cell lines Mia Paca2 and Panc1, and to a lesser extent in vivo on Mia Paca2 cell tumour growth. Specifically, masitinib at 10 microM strongly sensitised Mia Paca2 cells to gemcitabine (>400-fold reduction in IC(50)); and moderately sensitised Panc1 cells (10-fold reduction). Transcriptional analysis identified the Wnt/beta-catenin signalling pathway as down-regulated in the cell lines resensitised by the masitinib/gemcitabine combination.

CONCLUSIONS

These data establish proof-of-concept that masitinib can sensitise gemcitabine-refractory pancreatic cancer cell lines and warrant further in vivo investigation. Indeed, such an effect has been recently observed in a phase 2 clinical study of patients with pancreatic cancer who received a masitinib/gemcitabine combination.

New treatment options for advanced pancreatic cancer

Pancreatic cancer has a very high mortality rate and affects approximately 230,000 individuals worldwide. Gemcitabine has become established as the standard therapy for advanced pancreatic cancer; however, the survival advantage is small. Adjuvant chemotherapy using either 5-fluorouracil or gemcitabine is now established in pancreatic cancer as an alternative therapy. Combinations of gemcitabine with either platin agents or capecitabine may be advantageous. Anti-EGFR and anti-VEGF agents have been unsuccessful but multiple tyrosine kinase inhibitors are under investigation. Of the increasing number of immunological agents, the GV1001 antitelomerase vaccine holds some interest. Targeted agents against important mitogenic pathways, including MEK/ERK, Src, PI3K/Akt, mTOR, Hedgehog and NF-kappaB, as well as agents targeting histone deacetylase, poly(ADP-ribose) polymerase, heat shock protein 90 and other agents such as beta-lapachone, hold considerable interest for further development. However, the probability of individual success is low.