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KRAS mutation is associated with the progression and growth of pancreatic cancer and contributes to chemo-resistance, which poses a significant clinical challenge in pancreatic cancer. Here, we developed a RT22-ep59 antibody (Ab) that directly targets the intracellularly activated GTP-bound form of oncogenic KRAS mutants after it is internalized into cytosol by endocytosis through tumor-associated receptor of extracellular epithelial cell adhesion molecule (EpCAM) and investigated its synergistic anticancer effects in the presence of gemcitabine in pancreatic cancer. We first observed that RT22-ep59 specifically recognized tumor-associated EpCAM and reached the cytosol by endosomal escape. In addition, the anticancer effect of RT22-ep59 was observed in the high-EpCAM-expressing pancreatic cancer cells and gemcitabine-resistant pancreatic cancer cells, but it had little effect on the low-EpCAM-expressing pancreatic cancer cells. Additionally, co-treatment with RT22-ep59 and gemcitabine synergistically inhibited cell viability, migration, and invasion in 3D-cultures and exhibited synergistic anticancer activity by inhibiting the RAF/ERK or PI3K/AKT pathways in cells with high-EpCAM expression. In an orthotopic mouse model, combined administration of RT22-ep59 and gemcitabine significantly inhibited tumor growth. Furthermore, the co-treatment suppressed cancer metastasis by blocking EMT signaling in vitro and in vivo. Our results demonstrated that RT22-ep59 synergistically increased the antitumor activity of gemcitabine by inhibiting RAS signaling by specifically targeting KRAS. This indicates that co-treatment with RT22-ep59 and gemcitabine might be considered a potential therapeutic strategy for pancreatic cancer patients harboring KRAS mutation. [ABSTRACT FROM AUTHOR]

Background: The standard of care for patients with resected stage I to stage III pancreatic ductal adenocarcinoma (PDAC) is adjuvant gemcitabine-based chemotherapy. The role of adjuvant treatment in patients with subcentimeter, stage IA PDAC is unknown. The current study evaluated the effect of adjuvant treatment on survival outcomes among patients with American Joint Committee on Cancer/International Union Against Cancer stage IA (T1N0) resected PDAC using the National Cancer Data Base (NCDB).Methods: A retrospective review of the NCDB was conducted for patients diagnosed with T1 (tumor limited to the pancreas and measuring ≤2 cm in greatest dimension), lymph node-negative (N0), resected PDAC between 2004 and 2013. Patient demographics, histology, adjuvant treatment, and survival trends were examined. Kaplan-Meier analysis and log-rank tests were performed to determine the unadjusted association between overall survival (OS), tumor size, and treatment.Results: A total of 876 patients met the inclusion criteria. The patients had a mean age of 66.2 years (range, 32-90 years); approximately 83.3% were white (730 patients) and 53.1% were female (465 patients). Approximately 45.9% of the patients had moderately differentiated tumor histology (402 patients); 70.0% (613 patients) had tumors measuring 1 to 2 cm (T1c) and 30.0% (263 patients) had tumors measuring <1 cm (T1a/T1b). Approximately 94.2% of patients had negative surgical margins (815 patients) and 46.9% (410 patients) received adjuvant therapy. The median OS was significantly different for patients who received adjuvant therapy compared with patients who did not (70.7 months vs 46.9 months; P = .0001). For patients with tumors measuring <1 cm, survival was not found to be significantly different between patients who received adjuvant treatment compared with those who did not (not reached vs 85.3 months; P = .54). In the multivariable analysis, none of the covariates (treatment group, Charlson-Deyo Score, age, insurance, and facility status) demonstrated significant differences for patients with tumors measuring <1 cm.Conclusions: The current study is the first to demonstrate no survival benefit for adjuvant therapy in patients with resected subcentimeter PDAC. [ABSTRACT FROM AUTHOR]

Background and Aims: Pancreatic cancer is an aggressive malignancy with poor prognosis. Gemcitabine is the standard chemotherapeutic drug used to treat the disease; however, it has a low response rate. Therefore, there is an urgent need to develop new and safe therapies to enhance sensitivity to gemcitabine in treating pancreatic cancer.Methods: The synergistic effect of gemcitabine combined with specific B cell CLL/lymphoma 2 (Bcl-2) inhibitor ABT-199 against pancreatic cancer was tested using cell viability, cell cycle, and apoptosis assays in vitro and in an MIA Paca-2 xenograft model in vivo. Its underlying mechanism was explored using western blotting analysis of Bcl-2 family proteins.Results: ABT-199 not only enhanced the effect of gemcitabine on cell growth inhibition but also promoted gemcitabine-induced apoptosis in pancreatic cancer cell lines. Gemcitabine decreased the expression of anti-apoptotic protein Mcl-1 but increased the expression of anti-apoptotic protein Bcl-2. ABT-199 downregulated the gemcitabine-induced production of Bcl-2 and increased the expression of pro-apoptotic protein Bcl-2 interacting protein (BIM). Mouse xenograft experiments also confirmed the synergistic effect of gemcitabine and ABT-199 on tumor growth inhibition and the induction of tumor cell apoptosis.Conclusion: Our results indicated that ABT-199 improved the anti-tumor effect of gemcitabine on pancreatic cancer by downregulating gemcitabine-induced overexpression of Bcl-2. ABT-199 has already been investigated in phase 3 clinical trials for chronic lymphocytic leukemia; therefore, it may serve as a potential drug to improve the sensitivity of pancreatic cancer to gemcitabine. [ABSTRACT FROM AUTHOR]

As a fundamental metabolic enzyme, anti-Thymidylate synthase (TS) strategy has been shown to be an effective therapy for human cancers. However, the genuine effects of TS in pancreatic ductal adenocarcinoma (PDA) are still conflicting. We systemically assessed the prognostic value and whether TS associated with malignant progression in PDA. Protein and mRNA expression level of TS were evaluated in en bloc PDA samples, the prognostic effect of TS expressed in cytoplasm or cytonuclear was determined separately in the first time. The impact of TS on tumor cell behaviors was assessed in in vitro assays, and the TS associated metastatic potential was further determined in two different PDA metastatic models. The retrospective clinical analysis firstly demonstrated that tumor cytonuclear TS expression was positively correlated with lymphatic metastasis and negatively correlated with the overall survival (OS) in PDA patients. The subsequent experiments further confirmed that TS depletion can effectively abate EMT (epithelial to mesenchymal) process in in vitro and decline most of the metastatic lesions in two different PDA mice models, and the deoxythymidine monophosphate (dTMP) biosynthesis malfunction resulted imbalanced dNTP pools may be the fundamental causation. Collectively, the present study suggested the prospective strategy of combined anti-TS scheme for metastatic PDA, and we strongly suggest further clinical standardization research with a large cohort to verify the prognostic value and the therapeutic potential of TS in PDA. [ABSTRACT FROM AUTHOR]

Background and Aims: Pancreatic ductal adenocarcinoma (PDAC) represents the fourth cause of cancer-related death. We aimed to evaluate whether gemcitabine treatment shapes the gut microbiota in a model of PDAC xenografted mice.Materials and Methods: Pancreatic cancer xenograft mice were subjected to gemcitabine injection once per week for 3 weeks to assess the tumor volume as compared to control mice injected with normal saline solution. The composition of fecal microbiota, the activation of NF-kB pathway in cancer tissues and the serum metabolomics were further analyzed.Results: Gemcitabine considerably decreases the proportion of Gram- positive Firmicutes (from about 39 to 17%) and the Gram- negative Bacteroidetes (from 38 to 17%) which are the two dominant phyla in the gut of tumor-bearing control mice. This downshift was replaced by an increase of Proteobacteria (Escherichia coli and Aeromonas hydrophila) from 15 up to 32% and Verrucomicrobia (Akkermansia muciniphila) from 5 to 33% in the gut of drug-receiving mice. An overall increase in inflammation-associated bacteria was observed upon gemcitabine. Consistently, activation of the NF-kB canonical pathway was found in cancer tissues from gemcitabine-treated mice. Serum metabolomics revealed a significant decrease of the purine compounds inosine and xanthine, and a decreasing trend for their metabolically-related molecule hypoxanthine.Discussion: Understanding chemotherapy side effects may explain the lack of activity or the chemoresistant processes and it may help to set up strategies to improve the effectiveness of therapy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the safety and efficacy of mocetinostat (a Class I/IV HDAC inhibitor) in combination with gemcitabine in patients with solid tumors, including pancreatic cancer.Methods: In this open-label, non-randomized Phase I/II study (NCT00372437) sequential cohorts of patients with solid tumors received gemcitabine (1000 mg/m2, day 1 of three consecutive weeks, 4-week cycles) and oral mocetinostat [50-110 mg, three times per week (TIW)]. The maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) was determined based on dose-limiting toxicities in Cycle 1 (Phase I study). The MTD/RP2D was further evaluated in patients with advanced pancreatic cancer (Phase II study) using a two-stage design. The Phase II primary endpoint was overall response rate (ORR).Results: Forty-eight patients were enrolled into the Phase I (n = 25) and Phase II (n = 23) studies. In the Phase I study, the MTD/RP2D was mocetinostat 90 mg TIW + gemcitabine 1000 mg/m2. Grade ≥ 3 treatment-related adverse events (AEs) were reported by 81% of all patients, the most frequent being fatigue (38%) and thrombocytopenia (19%). The ORR was 11% in the Phase I study (n = 2 patients with pancreatic cancer, responses lasting for 16.8 and 4.0 months, respectively). As no responses were seen in the Phase II cohort, the study was terminated.Conclusions: Mocetinostat TIW in combination with gemcitabine was associated with significant toxicities in patients with advanced pancreatic cancer. The level of clinical activity of this treatment combination was not considered high enough to merit further testing in this setting. [ABSTRACT FROM AUTHOR]

Purpose: Following a previously published pre-clinical validation, this phase I study evaluated the safety, maximum tolerated dose, anti-tumour activity and immune status of a gemcitabine-chloroquine combination as a first- or late-line treatment in patients with metastatic or unresectable pancreatic cancer.Methods: In this 3 + 3 dose escalation study, patients received a single weekly standard dose of intravenous gemcitabine, followed by single weekly oral intake of 100, 200 or 300 mg of chloroquine. Tumour response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1. Immune status was evaluated by RT-PCR to measure the relative expression of immune-related genes in peripheral blood mononuclear cells (PBMCs).Results: Overall, nine patients [median age 72 years; interquartile range (IQR), 68-78 years] were treated. No dose-limiting toxicities as defined in the protocol were observed. Three patients experienced partial response, and two patients had stable disease. The median time to progression was 4 months (95% CI 0.8-7.2), and the median overall survival was 7.6 months (95% CI 5.3-9.9). Among 86 assayed immune genes, three were significantly differentially expressed in PBMCs from responding versus non-responding patients: interferon-gamma receptor-1, toll-like receptor 2, and beta-2 microglobulin.Conclusions: The addition of chloroquine to gemcitabine was well tolerated and showed promising effects on the clinical response to the anti-cancer chemotherapy. Based on these initial results, the efficacy of the gemcitabine-chloroquine combination should be further assessed. [ABSTRACT FROM AUTHOR]

Purpose: Transforming growth factor-beta inhibitors may enhance the antitumor activity of gemcitabine with acceptable safety and tolerability. This open-label, multicenter, non-randomized phase 1b study assessed the safety/tolerability, pharmacokinetics, and tumor response of galunisertib plus gemcitabine in Japanese patients with advanced or metastatic pancreatic cancer.Methods: During each 28-day cycle, galunisertib 150 mg was administered orally twice daily (300 mg/day) for 14 days, followed by 14 days of rest. Gemcitabine 1000 mg/m2 was intravenously given on Days 8, 15, and 22. Safety was assessed by the incidence of dose-limiting toxicities (DLTs) in the first cycle and treatment-emergent adverse events (TEAEs). Efficacy was assessed by antitumor activity and changes in carbohydrate antigen 19-9 (CA19-9).Results: No DLTs were reported. All 7 enrolled patients had ≥1 TEAE, of which the most common included anorexia, decreased neutrophil count, and decreased white blood cell count. Grade ≥3 TEAEs were observed in 6 patients; 4 patients had Grade ≥3 TEAEs (decreased neutrophil, white blood cell, and lymphocyte count; hypophosphatemia) considered possibly related to study drug(s). The pharmacokinetic profile of galunisertib in combination with gemcitabine was similar to that previously observed for galunisertib alone. The clinical response [complete response (CR), partial response (PR), or stable disease] rate was 42.9%, and the median progression-free survival was 64 days; no CR/PR were achieved.Conclusion: Galunisertib plus gemcitabine had an acceptable safety/tolerability profile with evidence of efficacy in Japanese patients with advanced or metastatic pancreatic cancer. [ABSTRACT FROM AUTHOR]

Purpose: To determine a recommended dose for a biweekly combination neoadjuvant chemotherapy including gemcitabine, nab-paclitaxel, and S-1 (GAS) for patients with locally advanced pancreatic ductal adenocarcinoma (LAPC).Methods: Patients with borderline resectable or unresectable LAPC without distant metastasis were eligible for this study. The planned dosages of gemcitabine (mg/m2, day 1), nab-paclitaxel (mg/m2, day 1), and S-1 (mg/day, days 1-7) were 800/100/60-100 at level 1, and 1000/125/60-100 at level 2. The treatment cycle was repeated every 2 weeks, and patients were assessed for resectability and response to the treatment after 6 cycles. This study was registered with UMIN Clinical Trial Registry (UMIN000016630).Results: We enrolled 16 patients with LAPC in this study. At dose level 1, one of 8 patients experienced dose-limiting toxicity (DLT). One of the next 8 patients also experienced DLT at dose level 2. Based on these results, level 2 was considered the recommended dose for this regimen. Pancreatectomy with curative intent could be performed in 13 of the 16 patients. R0 resection was performed in 12 of 13 patients.Conclusion: In conclusion, recommended doses for a biweekly GAS chemotherapy regimen were determined as nab-paclitaxel: 125 mg/m2, gemcitabine: 1000 mg/m2 on day 1, S-1: <1.25 m2, 60 mg; 1.25-1.5 m2, 80 mg; >1.5 m2, 100 mg twice a day on days 1-7. GAS chemotherapy showed good preliminary efficacy with mild toxicity in this study, and warrants a further phase 2 trial to investigate the efficacy of the GAS regimen for LAPC. [ABSTRACT FROM AUTHOR]

Background: The ESPAC-3 trial showed that adjuvant gemcitabine is the standard of care based on similar survival to and less toxicity than adjuvant 5-fluorouracil/folinic acid in patients with resected pancreatic cancer. Other clinical trials have shown better survival and tumour response with gemcitabine and capecitabine than with gemcitabine alone in advanced or metastatic pancreatic cancer. We aimed to determine the efficacy and safety of gemcitabine and capecitabine compared with gemcitabine monotherapy for resected pancreatic cancer.Methods: We did a phase 3, two-group, open-label, multicentre, randomised clinical trial at 92 hospitals in England, Scotland, Wales, Germany, France, and Sweden. Eligible patients were aged 18 years or older and had undergone complete macroscopic resection for ductal adenocarcinoma of the pancreas (R0 or R1 resection). We randomly assigned patients (1:1) within 12 weeks of surgery to receive six cycles of either 1000 mg/m2 gemcitabine alone administered once a week for three of every 4 weeks (one cycle) or with 1660 mg/m2 oral capecitabine administered for 21 days followed by 7 days' rest (one cycle). Randomisation was based on a minimisation routine, and country was used as a stratification factor. The primary endpoint was overall survival, measured as the time from randomisation until death from any cause, and assessed in the intention-to-treat population. Toxicity was analysed in all patients who received trial treatment. This trial was registered with the EudraCT, number 2007-004299-38, and ISRCTN, number ISRCTN96397434.Findings: Of 732 patients enrolled, 730 were included in the final analysis. Of these, 366 were randomly assigned to receive gemcitabine and 364 to gemcitabine plus capecitabine. The Independent Data and Safety Monitoring Committee requested reporting of the results after there were 458 (95%) of a target of 480 deaths. The median overall survival for patients in the gemcitabine plus capecitabine group was 28·0 months (95% CI 23·5-31·5) compared with 25·5 months (22·7-27·9) in the gemcitabine group (hazard ratio 0·82 [95% CI 0·68-0·98], p=0·032). 608 grade 3-4 adverse events were reported by 226 of 359 patients in the gemcitabine plus capecitabine group compared with 481 grade 3-4 adverse events in 196 of 366 patients in the gemcitabine group.Interpretation: The adjuvant combination of gemcitabine and capecitabine should be the new standard of care following resection for pancreatic ductal adenocarcinoma.Funding: Cancer Research UK. [ABSTRACT FROM AUTHOR]

Background: Although adjuvant chemotherapy with gemcitabine is standard care for resected pancreatic cancer, S-1 has shown non-inferiority to gemcitabine for advanced disease. We aimed to investigate the non-inferiority of S-1 to gemcitabine as adjuvant chemotherapy for pancreatic cancer in terms of overall survival.Methods: We did a randomised, open-label, multicentre, non-inferiority phase 3 trial undertaken at 33 hospitals in Japan. Patients who had histologically proven invasive ductal carcinoma of the pancreas, pathologically documented stage I-III, and no local residual or microscopic residual tumour, and were aged 20 years or older were eligible. Patients with resected pancreatic cancer were randomly assigned (in a 1:1 ratio) to receive gemcitabine (1000 mg/m(2), intravenously administered on days 1, 8, and 15, every 4 weeks [one cycle], for up to six cycles) or S-1 (40 mg, 50 mg, or 60 mg according to body-surface area, orally administered twice a day for 28 days followed by a 14 day rest, every 6 weeks [one cycle], for up to four cycles) at the data centre by a modified minimisation method, balancing residual tumour status, nodal status, and institutions. The primary outcome was overall survival in the two treatment groups, assessed in the per-protocol population, excluding ineligible patients and those not receiving the allocated treatment. The protocol prespecified that the superiority of S-1 with respect to overall survival was also to be assessed in the per-protocol population by a log-rank test, if the non-inferiority of S-1 was verified. We estimated overall and relapse-free survival using the Kaplan-Meier methods, and assessed non-inferiority of S-1 to gemcitabine using the Cox proportional hazard model. The expected hazard ratio (HR) for mortality was 0.87 with a non-inferiority margin of 1.25 (power 80%; one-sided type I error 2.5%). This trial is registered at UMIN CTR (UMIN000000655).Findings: 385 patients were randomly assigned to treatment between April 11, 2007, and June 29, 2010 (193 to the gemcitabine group and 192 to the S-1 group). Of these, three were exlcuded because of ineligibility and five did not receive chemotherapy. The per-protocol population therefore consisted of 190 patients in the gemcitabine group and 187 patients in the S-1 group. On Sept 15, 2012, following the recommendation from the independent data and safety monitoring committee, this study was discontinued because the prespecified criteria for early discontinuation were met at the interim analysis for efficacy, when all the protocol treatments had been finished. Analysis with the follow-up data on Jan 15, 2016, showed HR of mortality was 0.57 (95% CI 0.44-0.72, pnon-inferiority<0.0001, p<0.0001 for superiority), associated with 5-year overall survival of 24.4% (18.6-30.8) in the gemcitabine group and 44.1% (36.9-51.1) in the S-1 group. Grade 3 or 4 leucopenia, neutropenia, aspartate aminotransferase, and alanine aminotransferase were observed more frequently in the gemcitabine group, whereas stomatitis and diarrhoea were more frequently experienced in the S-1 group.Interpretation: Adjuvant chemotherapy with S-1 can be a new standard care for resected pancreatic cancer in Japanese patients. These results should be assessed in non-Asian patients.Funding: Pharma Valley Center, Shizuoka Industrial Foundation, Taiho Pharmaceutical. [ABSTRACT FROM AUTHOR]

Background: Pancreatic cancer is the fourth largest cause of cancer death in the United States and Europe with over 100,000 deaths per year in Europe alone. The overall 5-year survival ranges from 2-7 % and has hardly improved over the last two decades. Approximately 15 % of all patients have resectable disease at diagnosis, and of those, only a subgroup has a resectable tumour at surgical exploration. Data from cohort studies have suggested that outcome can be improved by preoperative radiochemotherapy, but data from well-designed randomized studies are lacking. Our PREOPANC phase III trial aims to test the hypothesis that median overall survival of patients with resectable or borderline resectable pancreatic cancer can be improved with preoperative radiochemotherapy.Methods/design: The PREOPANC trial is a randomized, controlled, multicentric superiority trial, initiated by the Dutch Pancreatic Cancer Group. Patients with (borderline) resectable pancreatic cancer are randomized to A: direct explorative laparotomy or B: after negative diagnostic laparoscopy, preoperative radiochemotherapy, followed by explorative laparotomy. A hypofractionated radiation scheme of 15 fractions of 2.4 gray (Gy) is combined with a course of gemcitabine, 1,000 mg/m(2)/dose on days 1, 8 and 15, preceded and followed by a modified course of gemcitabine. The target volumes of radiation are delineated on a 4D CT scan, where at least 95 % of the prescribed dose of 36 Gy in 15 fractions should cover 98 % of the planning target volume. Standard adjuvant chemotherapy is administered in both treatment arms after resection (six cycles in arm A and four in arm B). In total, 244 patients will be randomized in 17 hospitals in the Netherlands. The primary endpoint is overall survival by intention to treat. Secondary endpoints are (R0) resection rate, disease-free survival, time to locoregional recurrence or distant metastases and perioperative complications. Secondary endpoints for the experimental arm are toxicity and radiologic and pathologic response.Discussion: The PREOPANC trial is designed to investigate whether preoperative radiochemotherapy improves overall survival by means of increased (R0) resection rates in patients with resectable or borderline resectable pancreatic cancer.Trial Registration: Trial open for accrual: 3 April 2013 The Netherlands National Trial Register - NTR3709 (8 November 2012) EU Clinical Trials Register - 2012-003181-40 (11 December 2012). [ABSTRACT FROM AUTHOR]

Background: Treatment options for patients with locally advanced pancreatic cancer include surgery, chemotherapy as well as radiotherapy. In many cases, surgical resection is not possible, and therefore treatment alternatives have to be performed. Chemoradiation has been established as a convincing treatment alternative for locally advanced pancreatic cancer. Carbon ions offer physical and biological characteristics. Due to their inverted dose profile and the high local dose deposition within the Bragg peak precise dose application and sparing of normal tissue is possible. Moreover, in comparison to photons, carbon ions offer an increased relative biological effectiveness (RBE), which can be calculated between 1.16 and 2.46 depending on the pancreatic cancer cell line as well as the endpoint analyzed. Japanese Data on the evaluation of carbon ion radiation therapy showed promising results for patients with pancreatic cancer.Methods and Design: The present PHOENIX-01 trial evaluates carbon ion radiotherapy using the active rasterscanning technique in patients with advanced pancreatic cancer in combination with weekly gemcitabine and adjuvant gemcitabine. Primary endpoint is toxicity, secondary endpoints are overall survival, progression-free survival and response.Discussion: The physical and biological properties of the carbon ion beam promise to improve the therapeutic ratio in patients with pancreatic cancer: Due to the inverted dose profile dose deposition in the entry channel of the beam leads to sparing of normal tissue; the Bragg peak can be directed into the defined target volume, and the sharp dose fall-off thereafter again spares normal tissue behind the target volume. The higher RBE of carbon ions, which has been shown also for pancreatic cancer cell lines in the preclinical setting, is likely to contribute to an increase in local control, and perhaps in OS. Early data from Japanese centers have shown promising results. In conclusion, this is the first trial to evaluate actively delivered carbon ion beams in patients with locally advanced pancreatic cancer within a dose-escalation strategy.Trial Registration: NCT01795274. [ABSTRACT FROM AUTHOR]

Background: Chk1 inhibitors have emerged as promising anticancer therapeutic agents particularly when combined with antimetabolites such as gemcitabine, cytarabine or hydroxyurea. Here, we address the importance of appropriate drug scheduling when gemcitabine is combined with the Chk1 inhibitor MK-8776, and the mechanisms involved in the schedule dependence.Methods: Growth inhibition induced by gemcitabine plus MK-8776 was assessed across multiple cancer cell lines. Experiments used clinically relevant "bolus" administration of both drugs rather than continuous drug exposures. We assessed the effect of different treatment schedules on cell cycle perturbation and tumor cell growth in vitro and in xenograft tumor models.Results: MK-8776 induced an average 7-fold sensitization to gemcitabine in 16 cancer cell lines. The time of MK-8776 administration significantly affected the response of tumor cells to gemcitabine. Although gemcitabine induced rapid cell cycle arrest, the stalled replication forks were not initially dependent on Chk1 for stability. By 18 h, RAD51 was loaded onto DNA indicative of homologous recombination. Inhibition of Chk1 at 18 h rapidly dissociated RAD51 leading to the collapse of replication forks and cell death. Addition of MK-8776 from 18-24 h after a 6-h incubation with gemcitabine induced much greater sensitization than if the two drugs were incubated concurrently for 6 h. The ability of this short incubation with MK-8776 to sensitize cells is critical because of the short half-life of MK-8776 in patients' plasma. Cell cycle perturbation was also assessed in human pancreas tumor xenografts in mice. There was a dramatic accumulation of cells in S/G₂ phase 18 h after gemcitabine administration, but cells had started to recover by 42 h. Administration of MK-8776 18 h after gemcitabine caused significantly delayed tumor growth compared to either drug alone, or when the two drugs were administered with only a 30 min interval.Conclusions: There are two reasons why delayed addition of MK-8776 enhances sensitivity to gemcitabine: first, there is an increased number of cells arrested in S phase; and second, the arrested cells have adequate time to initiate recombination and thereby become Chk1 dependent. These results have important implications for the design of clinical trials using this drug combination. [ABSTRACT FROM AUTHOR]

Background: Only a few clinical trials have been conducted in patients with advanced pancreatic cancer after failure of first-line gemcitabine-based chemotherapy. Therefore, there is no current consensus on the treatment of these patients. We conducted a randomised phase II study of the modified FOLFIRI.3 (mFOLFIRI.3; a regimen combining 5-fluorouracil (5-FU), folinic acid, and irinotecan) and modified FOLFOX (mFOLFOX; a regimen combining folinic acid, 5-FU, and oxaliplatin) regimens as second-line treatments in patients with gemcitabine-refractory pancreatic cancer.Methods: The primary end point was the 6-month overall survival rate. The mFOlFIRI.3 regimen consisted of irinotecan (70 mg m(-2); days 1 and 3), leucovorin (400 mg m(-2); day 1), and 5-FU (2000 mg m(-2); days 1 and 2) every 2 weeks. The mFOLFOX regimen was composed of oxaliplatin (85 mg m(-2); day 1), leucovorin (400 mg m(-2); day 1), and 5-FU (2000 mg m(-2); days 1 and 2) every 2 weeks.Results: Sixty-one patients were randomised to mFOLFIRI.3 (n=31) or mFOLFOX (n=30) regimen. The six-month survival rates were 27% (95% confidence interval (CI)=13-46%) and 30% (95% CI=15-49%), respectively. The median overall survival periods were 16.6 and 14.9 weeks, respectively. Disease control was achieved in 23% (95% CI=10-42%) and 17% patients (95% CI=6-35%), respectively. The number of patients with at least one grade 3/4 toxicity was identical (11 patients, 38%) in both groups: neutropenia (7 patients under mFOLFIRI.3 regimen vs 6 patients under mFOLFOX regimen), asthaenia (1 vs 4), vomiting (3 in both), diarrhoea (2 vs 0), and mucositis (1 vs 2).Conclusion: Both mFOLFIRI.3 and mFOLFOX regimens were tolerated with manageable toxicity, offering modest activities as second-line treatments for patients with advanced pancreatic cancer, previously treated with gemcitabine. [ABSTRACT FROM AUTHOR]

The high mobility group A1 (HMGA1) proteins are overexpressed in pancreatic cancers. They are architectural nuclear proteins, which regulate expression of multiple genes implicated in the malignant phenotype. In this study, we hypothesized that HMG A1 silencing will promote chemosensitivity in pancreatic adenocarcinoma. We studied highly malignant pancreatic adenocarcinoma cell lines (MiaPaCa2 and PANC1). Lentiviral short-hairpin RNA (shHMGA1) expression vectors targeting HMGA1 were used for generation of lentiviral particles. Stable transfectants were developed after lentiviral transduction. Nuclear expression of HMGA1 was assayed using Western blot analysis. Chemosensitivity to gemcitabine was determined by IC50 analysis. Caspase activity was quantitated using fluorometric caspase profiling. Apoptosis was assessed by flow cytometric analysis. Lentivirus-mediated RNA interference resulted in 90% silencing of HMGA1 expression in each of MiaPaCa2 and PANC1 cell lines. HMGA1 silencing enhanced chemosensitivity to gemcitabine with an approximately 50% reduction in IC50 in each cell line. Lentivirus-mediated HMGA1 silencing promoted the activation of caspases 3, 2, 9, and 8, on exposure to gemcitabine. HMGA1 silencing resulted in reduction in Akt kinase activity. Lentivirus-mediated RNA interference of HMGA1 promoted chemosensitivity to gemcitabine in pancreatic adenocarcinoma. HMGA1 may represent a novel therapeutic target in pancreatic cancer. [Copyright &y& Elsevier]

Background: To study the pharmacokinetics and clinical outcome of gemcitabine (2'-2'-difluoro-deoxcytidine [dFdC]) during intra-arterial versus intravenous delivery in locally advanced and regionally metastatic pancreatic cancer. Patients and methods: Seven patients with unresectable pancreatic cancer received escalating intra-arterial doses of gemcitabine ranging from 800 to 1400 mg/m², after selective embolisation of all pancreatic blood supply, except for the tumour-feeding arteries. Four patients received intravenous gemcitabine (control). Venous blood samples at different time intervals were taken throughout 270 minutes for pharmacokinetic analyses of gemcitabine and its inactive metabolite 2'-2'-difluorodeoxyuridine (dFdU). Results: Pharmacokinetic data revealed differences in plasma concentrations between intra-arterial and intravenous delivery routes. The plasma concentration-time curve of gemcitabine during and after cessation of intra-arterial pancreatic target administration through the proximal splenic artery showed a profile with an area under the plasma concentration-time curve from 0 to 270 minutes (intra-arterial 29.0 ± 0.4 vs intravenous 331.0 ± 2.7 ng • min/mL; p < 0.0001) and peak plasma concentration (intra-arterial 1.1 ± 0.2 vs intravenous 7.6 ± 2.0 ng/mL; p < 0.0001) significantly lower than that for the corresponding systemic intravenous route. A plot of ln (% of dose) versus time showed a bi-compartmentalised metabolic model for intravenous administration of gemcitabine, one indicating rapid conversion of gemcitabine to dFdU, and another at a significantly lower affinity resulting in no conversion. Hence, this could be the main reason why dFdU was not detected in the systemic circulation during pancreatic intra-arterial target delivery. Furthermore, during intravenous administration a pseudo first-order rate constant (≈0.20 min-1) for in vivo conversion of gemcitabine to dFdU was estimated, indicating a rapid cellular deamination which was not shown in the intra-arterial route. Clinically, one patient had a partial response and six patients had a stable disease after intra-arterial administration of gemcitabine. The median time to disease progression was 4 months and the median overall survival was 5 months. One patient survived for 26 months. No grade III or IV toxicity was documented. Conclusion: Intra-arterial administration of gemcitabine has a major advantage related to reduced toxicity as increasing the dose through this administration route will eventually result in pancreatic cellular drug target delivery prior to systemic availability. Despite the low number of patients recruited, the clinical results are encouraging and this approach should be tested in a randomised study. [ABSTRACT FROM AUTHOR]

Pancreatic cancer remains a highly chemoresistant malignancy. Gemcitabine, the most effective first-line agent available, acts by disrupting cellular replication. Caspases belong to a family of proteases that function as key components of the apoptotic death machinery. We investigated the mechanisms by which gemcitabine blocks proliferation and whether it can induce apoptosis in pancreatic cancer cells. Quiescent pancreatic cancer cells (BxPC-3) were stimulated to proliferate (10% fetal calf serum) with or without gemcitabine, PS-341 (26S proteasome inhibitor), or both. Proliferation was measured by MTT assay and apoptosis by propidium iodine staining. To determine activation of the apoptotic regulatory cell proteins, caspase-3 and cleavage of poly(ADP-ribose)polymerase (PARP) into its 85-kDa fragment were assessed by Western blotting. Gemcitabine at even low doses (10 μmol/L) significantly inhibited cellular proliferation, whereas PS-341 (10 nmol/L) had no effect. With combined treatment, PS-341 potentiated the antiproliferative effects of gemcitabine (P=0.001). At 48 hours, the apoptotic fraction was greatly enhanced by the presence of PS-341 compared with gemcitabine alone. Caspase-3 accumulated as early as 30 minutes and was associated with cleavage of PARP to its apoptotic fragment. Gemcitabine, a nucleoside analogue, may in part exert its antiproliferative effects by directing pancreatic cancer cells to a default pathway of apoptosis. 26S proteasome inhibition potentiates this effect, suggesting its potential clinical value against chemoresistance in pancreatic cancer. [Copyright &y& Elsevier]

Objective: Patients with pancreatic cancer have only short survival after diagnosis, irrespective of treatment. The aim of this study was to perform a health economic evaluation of present standard treatment (in most cases, palliative treatment in combination with best supportive care) versus palliative treatment with gemcitabine in combination with best supportive care in patients with locally advanced pancreatic carcinoma.Design: The use of resources and associated costs according to present treatment practice were estimated and calculated retrospectively. Costs were calculated from diagnosis until death. Actual costs and treatment effects for the patient population were compared with expected treatment costs for the same population if they additionally received gemcitabine.Setting: This economic analysis is based on a hypothetical comparison and was performed from a societal point of view.Patients and Participants: The study population consisted of all patients diagnosed with pancreatic cancer during the year April 1994 to March 1995 and resident in Stockholm County, Sweden. After exclusions, 184 patients were included in the economic analysis.Interventions: The effects of gemcitabine treatment on survival and disease-related symptoms were extrapolated from the results of a recent randomised clinical trial in North America.Main Outcome Measures and Results: The estimated additional costs for chemotherapy, treatment of adverse effects and in- and outpatient care associated with gemcitabine treatment were approximately 132,000 Swedish kronor (SEK) per life-year gained. This result is comparable with costs per life-year gained for other accepted treatments, for example those of home dialysis and kidney transplants for chronic renal failure.Conclusions: Treatment with gemcitabine in patients with pancreatic cancer may be a cost-effective alternative, but the results need to be confirmed in future randomised trials. [ABSTRACT FROM AUTHOR]