Phase I/II Study of LDE225 in Combination with Gemcitabine and Nab-Paclitaxel in Patients with Metastatic Pancreatic Cancer.

BACKGROUND: Desmoplasia is a central feature of the tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC). LDE225 is a pharmacological Hedgehog signaling pathway inhibitor and is thought to specifically target tumor stroma. We investigated the combined use of LDE225 and chemotherapy to treat PDAC patients. METHODS: This was a multi-center, phase I/II study for patients with metastatic PDAC establishing the maximum tolerated dose of LDE225 co-administered with gemcitabine and nab-paclitaxel (phase I) and evaluating the efficacy and safety of the treatment combination after prior FOLFIRINOX treatment (phase II). Tumor microenvironment assessment was performed with quantitative MRI using intra-voxel incoherent motion diffusion weighted MRI (IVIM-DWI) and dynamic contrast-enhanced (DCE) MRI. RESULTS: The MTD of LDE225 was 200 mg once daily co-administered with gemcitabine 1000 mg/m2 and nab-paclitaxel 125 mg/m2. In phase II, six therapy-related grade 4 adverse events (AE) and three grade 5 were observed. In 24 patients, the target lesion response was evaluable. Three patients had partial response (13%), 14 patients showed stable disease (58%), and 7 patients had progressive disease (29%). Median overall survival (OS) was 6 months (IQR 3.9-8.1). Blood plasma fraction (DCE) and diffusion coefficient (IVIM-DWI) significantly increased during treatment. Baseline perfusion fraction could predict OS (>222 days) with 80% sensitivity and 85% specificity. CONCLUSION: LDE225 in combination with gemcitabine and nab-paclitaxel was well-tolerated in patients with metastatic PDAC and has promising efficacy after prior treatment with FOLFIRINOX. Quantitative MRI suggested that LDE225 causes increased tumor diffusion and works particularly well in patients with poor baseline tumor perfusion.

Radiofrequency and Microwave Ablation Compared to Systemic Chemotherapy and to Partial Hepatectomy in the Treatment of Colorectal Liver Metastases: A Systematic Review and Meta-Analysis.

PURPOSE: To assess safety and outcome of radiofrequency ablation (RFA) and microwave ablation (MWA) as compared to systemic chemotherapy and partial hepatectomy (PH) in the treatment of colorectal liver metastases (CRLM). METHODS: MEDLINE, Embase and the Cochrane Library were searched. Randomized trials and comparative observational studies with multivariate analysis and/or matching were included. Guidelines from National Guideline Clearinghouse and Guidelines International Network were assessed using the AGREE II instrument. RESULTS: The search revealed 3530 records; 328 were selected for full-text review; 48 were included: 8 systematic reviews, 2 randomized studies, 26 comparative observational studies, 2 guideline-articles and 10 case series; in addition 13 guidelines were evaluated. Literature to assess the effectiveness of ablation was limited. RFA + systemic chemotherapy was superior to chemotherapy alone. PH was superior to RFA alone but not to RFA + PH or to MWA. Compared to PH, RFA showed fewer complications, MWA did not. Outcomes were subject to residual confounding since ablation was only employed for unresectable disease. CONCLUSION: The results from the EORTC-CLOCC trial, the comparable survival for ablation + PH versus PH alone, the potential to induce long-term disease control and the low complication rate argue in favour of ablation over chemotherapy alone. Further randomized comparisons of ablation to current-day chemotherapy alone should therefore be considered unethical. Hence, the highest achievable level of evidence for unresectable CRLM seems reached. The apparent selection bias from previous studies and the superior safety profile mandate the setup of randomized controlled trials comparing ablation to surgery.

A phase Ib study of everolimus combined with metformin for patients with advanced cancer.

Background The efficacy to monotherapy with the mTOR inhibitor everolimus in advanced cancer is often limited due to therapy resistance. Combining everolimus with metformin may decrease the chance of therapy resistance. Methods Patients received everolimus and metformin in a 3 + 3 dose-escalation scheme. Objectives were to determine the dose-limiting toxicities (DLTs), maximum tolerated dose, toxic effects, pharmacokinetics and anti-tumour efficacy. Results 9 patients received study treatment for a median duration of 48 days (range: 4-78). 6 patients discontinued due to toxicity and 3 patients because of progressive disease. At the starting dose level of 10 mg everolimus qd and 500 mg metformin bid, 3 out of 5 patients experienced a DLT. After de-escalation to 5 mg everolimus qd and 500 mg metformin bid, considerable toxicity was still observed and patient enrollment was terminated. In pharmacokinetic analyses, metformin was eliminated slower when co-administered with everolimus than as single-agent. After 9 weeks of treatment, 3 patients were still on study and all had stable disease. Conclusion The combination of everolimus and metformin is poorly tolerated in patients with advanced cancer. The pharmacokinetic interaction between everolimus and metformin may have implications for diabetic cancer patients that are treated with these drugs. Our results advocate for future clinical trials with combinations of other mTOR inhibitors and biguanides.

Dabigatran potentiates gemcitabine-induced growth inhibition of pancreatic cancer in mice.

Pancreatic cancer is one of the most lethal solid malignancies with little treatment options. We have recently shown that expression of protease activated receptor (PAR)-1 in the tumor microenvironment drives progression and induces chemoresistance of pancreatic cancer. As thrombin is the prototypical PAR-1 agonist, here we addressed the effect of the direct thrombin inhibitor dabigatran on pancreatic cancer growth and drug resistance in an orthotropic pancreatic cancer model. We show that dabigatran treatment did not affect primary tumor growth whereas it significantly increased tumor dissemination throughout the peritoneal cavity. Increased dissemination was accompanied by intratumoral bleeding and increased numbers of aberrant and/or collapsed blood vessels in the primary tumors. In combination with gemcitabine, dabigatran treatment limited primary tumor growth, did not induce bleeding complications and prevented tumor cell dissemination. Dabigatran was however not as efficient as genetic ablation of PAR-1 in our previous study suggesting that thrombin is not the main PAR-1 agonist in the setting of pancreatic cancer. Overall, we show that dabigatran potentiates gemcitabine-induced growth inhibition of pancreatic cancer but does not affect primary tumor growth when used as a monotherapy.

Metformin in patients with advanced pancreatic cancer: a double-blind, randomised, placebo-controlled phase 2 trial.

BACKGROUND: In preclinical work and retrospective population studies, the anti-diabetic drug metformin has been associated with antineoplastic activity and decreased burden of many cancers, including pancreatic cancer. There is therefore interest in the hypothesis that this drug might be repurposed for indications in oncology. We aimed to assess the efficacy of the addition of metformin to a standard systemic therapy in patients with advanced pancreatic cancer, and provide the first report of a clinical trial with a survival endpoint of metformin for an oncological indication. METHODS: We did this double-blind, randomised, placebo-controlled phase 2 trial at four centres in the Netherlands. Patients aged 18 years or older with advanced pancreatic cancer were randomly assigned (1:1), via a permutated computer-generated block allocation scheme (block size of six) to receive intravenous gemcitabine (1000 mg/m(2)) on days 1, 8, and 15 every 4 weeks and oral erlotinib (100mg) once daily in combination with either oral metformin or placebo twice daily. Metformin dose was escalated from 500 mg (in the first week) to 1000 mg twice daily in the second week. Randomisation was stratified by hospital, diabetes status, and tumour stage. The primary endpoint was overall survival at 6 months in the intention-to-treat population. This trial is complete and is registered with ClinicalTrials.gov, number NCT01210911. FINDINGS: Between May 31, 2010, and Jan 3, 2014, we randomly assigned 121 patients to receive gemcitabine and erlotinib with either placebo (n=61) or metformin (n=60). Overall survival at 6 months was 63·9% (95% CI 51·9-75·9) in the placebo group and 56·7% (44·1-69·2) in the metformin group (p=0·41). There was no difference in overall survival between groups (median 7·6 months [95% CI 6·1-9·1] vs 6·8 months [95% CI 5·1-8·5] in the metformin group; hazard ratio [HR] 1·056 [95% CI 0·72-1·55]; log-rank p=0·78). The most frequent grade 3-4 toxic effects were neutropenia (15 [25%] patients in placebo group vs 15 [25%] in metformin group), skin rash (six [10%] vs four [7%]), diarrhoea (three [5%] vs six [10%]), and fatigue (two [3%] vs six [10%]). INTERPRETATION: Addition of a conventional anti-diabetic dose of metformin does not improve outcome in patients with advanced pancreatic cancer treated with gemcitabine and erlotinib. Future research should include studies of more potent biguanides, and should focus on patients with hyperinsulinaemia and patients with tumours showing markers of sensitivity to energetic stress, such as loss of function of AMP kinase, a key regulator of cellular energy homoeostasis. FUNDING: Academic Medical Centre, Amsterdam, and The Terry Fox Foundation, Vancouver, Canada.

Preoperative chemoradiation therapy in combination with panitumumab for patients with resectable esophageal cancer: the PACT study.

PURPOSE: Preoperative chemoradiation therapy (CRT) has become the standard treatment strategy for patients with resectable esophageal cancer. This multicenter phase 2 study investigated the efficacy of the addition of the epidermal growth factor receptor (EGFR) inhibitor panitumumab to a preoperative CRT regimen with carboplatin, paclitaxel, and radiation therapy in patients with resectable esophageal cancer. METHODS AND MATERIALS: Patients with resectable cT1N1M0 or cT2-3N0 to -2M0 tumors received preoperative CRT consisting of panitumumab (6 mg/kg) on days 1, 15, and 29, weekly administrations of carboplatin (area under the curve [AUC] = 2), and paclitaxel (50 mg/m(2)) for 5 weeks and concurrent radiation therapy (41.4 Gy in 23 fractions, 5 days per week), followed by surgery. Primary endpoint was pathologic complete response (pCR) rate. We aimed at a pCR rate of more than 40%. Furthermore, we explored the predictive value of biomarkers (EGFR, HER 2, and P53) for pCR. RESULTS: From January 2010 until December 2011, 90 patients were enrolled. Patients were diagnosed predominantly with adenocarcinoma (AC) (80%), T3 disease (89%), and were node positive (81%). Three patients were not resected due to progressive disease. The primary aim was unmet, with a pCR rate of 22%. Patients with AC and squamous cell carcinoma reached a pCR of 14% and 47%, respectively. R0 resection was achieved in 95% of the patients. Main grade 3 toxicities were rash (12%), fatigue (11%), and nonfebrile neutropenia (11%). None of the biomarkers was predictive for response. CONCLUSIONS: The addition of panitumumab to CRT with carboplatin and paclitaxel was safe and well tolerated but could not improve pCR rate to the preset criterion of 40%.

Preoperative chemoradiotherapy in locally advanced gastric cancer, a phase I/II feasibility and efficacy study.

OBJECTIVES: This study was initiated to investigate the feasibility and efficacy of preoperative radiotherapy with weekly paclitaxel and carboplatin in locally advanced gastric cancer. METHODS: In a prospective study, patients with locally advanced gastric cancer stage IB-IV(M0) were treated with chemoradiotherapy followed by surgery 4-6 weeks after the last irradiation. Chemoradiotherapy consisted of radiation to a total dose of 45 Gy given in 25 fractions of 1.8 Gy, combined with concurrent weekly carboplatin and paclitaxel. RESULTS: Between December 2007 and January 2012, 25 patients with cT3 (64%) or cT4 (36%) gastric cancer were included. One patient discontinued concurrent chemotherapy in the 4th week due to toxicity, but completed radiotherapy. Another patient discontinued chemoradiotherapy after the 3rd week due to progressive disease. Grade III adverse events of chemoradiotherapy were: gastrointestinal 12%, haematological 12% and other 8%. All patients, except one who developed progressive disease, were operated. Surgical complications were: general/infectious 48%, anastomotic leakage 12%, and bowel perforation 8%. Postoperative mortality was 4%. Microscopically radical resection rate was 72%. Pathological complete response rate was 16% and near complete response rate 24%. CONCLUSIONS: In this study, preoperative chemoradiotherapy for patients with locally advanced gastric cancer was associated with manageable toxicity and encouraging pathological response rates.

Protease-activated receptor-1 drives pancreatic cancer progression and chemoresistance.

Protease activated receptor (PAR)-1 expression in tumor cells is associated with disease progression and overall survival in a variety of cancers of epithelial origin; however, the importance of PAR-1 in the tumor microenvironment remains unexplored. Utilizing an orthotopic pancreatic cancer model in which tumor cells are PAR-1 positive whereas stromal cells are PAR-1 negative, we show that PAR-1 expression in the microenvironment drives progression and induces chemoresistance of pancreatic cancer. PAR-1 enhances monocyte recruitment into the tumor microenvironment by regulating monocyte migration and fibroblast dependent chemokine production thereby inducing chemoresistance. Overall, our data identify a novel role of PAR-1 in the pancreatic tumor microenvironment and suggest that PAR-1 may be an attractive target to reduce drug resistance in pancreatic cancer.

Patterns of recurrence after surgery alone versus preoperative chemoradiotherapy and surgery in the CROSS trials.

PURPOSE: To analyze recurrence patterns in patients with cancer of the esophagus or gastroesophageal junction treated with either preoperative chemoradiotherapy (CRT) plus surgery or surgery alone. PATIENTS AND METHODS: Recurrence pattern was analyzed in patients from the previously published CROSS I and II trials in relation to radiation target volumes. CRT consisted of five weekly courses of paclitaxel and carboplatin combined with a concurrent radiation dose of 41.4 Gy in 1.8-Gy fractions to the tumor and pathologic lymph nodes with margin. RESULTS: Of the 422 patients included from 2001 to 2008, 418 were available for analysis. Histology was mostly adenocarcinoma (75%). Of the 374 patients who underwent resection, 86% were allocated to surgery and 92% to CRT plus surgery. On January 1, 2011, after a minimum follow-up of 24 months (median, 45 months), the overall recurrence rate in the surgery arm was 58% versus 35% in the CRT plus surgery arm. Preoperative CRT reduced locoregional recurrence (LRR) from 34% to 14% (P < .001) and peritoneal carcinomatosis from 14% to 4% (P < .001). There was a small but significant effect on hematogenous dissemination in favor of the CRT group (35% v 29%; P = .025). LRR occurred in 5% within the target volume, in 2% in the margins, and in 6% outside the radiation target volume. In 1%, the exact site in relation to the target volume was unclear. Only 1% had an isolated infield recurrence after CRT plus surgery. CONCLUSION: Preoperative CRT in patients with esophageal cancer reduced LRR and peritoneal carcinomatosis. Recurrence within the radiation target volume occurred in only 5%, mostly combined with outfield failures.

A phase I/II, non-randomized, feasibility/safety and efficacy study of the combination of everolimus, cetuximab and capecitabine in patients with advanced pancreatic cancer.

BACKGROUND: Improvements in knowledge of molecular mechanisms in cancer are the basis for new studies combining chemotherapy with targeted drugs. Inhibition of the epidermal growth factor receptor (EGFR) by erlotinib or cetuximab has limited or no activity, respectively, in pancreatic cancer. The crosstalk between EGFR and mammalian target of rapamycin (mTOR) pathways is a potential mechanism of resistance; therefore we conducted a study to explore safety and efficacy of multiple pathway inhibition by cetuximab and everolimus in combination with capecitabine. METHODS: Safety and efficacy of fixed standard dose cetuximab in combination with various dose levels of everolimus (5-10 mg/day) and capecitabine (600-800 mg/m(2) bid, 2 weeks every 3 weeks) were investigated in a phase I/II study in patients with advanced pancreatic cancer. The primary endpoint was objective response. RESULTS: Sixteen patients were treated in the phase I part at two dose levels. Mucositis, rash and hand-foot syndrome were dose-limiting toxicities. Dose level 1 (everolimus 5 mg/day, capecitabine 600 mg/m(2) bid for 2 weeks every 3 weeks and cetuximab 250 mg/m(2) weekly) was considered the maximum tolerated dose (MTD). Of 31 patients in the phase II part, partial response was documented in two patients (6.5%) and five (16.1%) had stable disease. Median overall survival was 5.0 months (CI 3.1-6.8). CONCLUSION: The schedule of capecitabine, everolimus and cetuximab resulted in considerable epidermal and mucosal toxicities and prevented escalation to optimal dose levels. Because of toxicity and low efficacy this treatment combination cannot be recommended for treatment in pancreatic cancer patients.

Coagulation activation and microparticle-associated coagulant activity in cancer patients. An exploratory prospective study.

Cancer increases the risk of venous thromboembolism (VTE). Here, we investigated the contribution of microparticle (MP)-dependent procoagulant activity to the prothrombotic state in these patients. In 43 cancer patients without VTE at study entry and 22 healthy volunteers, markers of in vivo and MP-dependent coagulation were measured and patients were prospectively followed for six months for the development of VTE. Procoagulant activity of MPs was measured in vitro using a tissue factor (TF)-independent phospholipid dependent test, a factor Xa-generation assay with and without anti-TF, and a fibrin generation test (FGT) with and without anti-factor VII(a). Markers of in vivo coagulation activation and total number of MPs at baseline were significantly elevated in cancer patients compared to controls (F1+2 246 vs. 156 pM, thrombin-antithrombin complexes 4.1 vs. 3.0 mg/l, D-dimer 0.76 vs. 0.22 mg/l and 5.53 x 106 vs. 3.37 x 106 MPs/ml). Five patients (11.6%) developed VTE. Patients with VTE had comparable levels of coagulation activation markers and phospholipid-dependent MP procoagulant activity. However, median TF-mediated Xa-generation (0.82 vs. 0.21 pg/ml, p=0.016) and median VIIa-dependent FGT (13% vs. 0%, p=0.036) were higher in the VTE group compared with the non-VTE group. In this exploratory study the overall hypercoagulable state in cancer patients was not associated directly with the MP phospholipid-dependent procoagulant activity. However, in the patients who developed VTE within six months when compared to those who did not, an increased MP procoagulant activity was present already at baseline, suggesting this activity can be used to predict VTE.

Fusion of intestinal epithelial cells with bone marrow derived cells is dispensable for tissue homeostasis.

The epithelial lining of the intestine is characterized by an immense cellular turn-over ascertaining an extensive regenerative capacity. Multiple reports suggest that besides the local intestinal stem cell pool, circulating cells of bone marrow origin (BMDCs) contribute to this process by fusing with the epithelial lineage. However, the functional relevance of these observations is unknown. In the present study we employ a model system in which we cannot only detect cell fusion but also examine the functional importance of this process in vivo. Our results indicate that fusion between BMDCs and intestinal epithelial cells is an extremely rare event under physiological conditions. More importantly, by employing a system in which fusion-derived cells can be specifically deleted after extensive tissue damage, we present evidence that cell fusion is not relevant for tissue regeneration. Our data decisively demonstrates that intestinal epithelial homeostasis and regeneration is not dependent on cell fusion involving BMDCs.

The developing cancer stem-cell model: clinical challenges and opportunities.

During the past decade, a stem-cell-like subset of cancer cells has been identified in many malignancies. These cells, referred to as cancer stem cells (CSCs), are of particular interest because they are believed to be the clonogenic core of the tumour and therefore represent the cell population that drives growth and progression. Many efforts have been made to design therapies that specifically target the CSC population, since this was predicted to be the crucial population to eliminate. However, recent insights have complicated the initial elegant model, by showing a dominant role for the tumour microenvironment in determining CSC characteristics within a malignancy. This is particularly important since dedifferentiation of non-tumorigenic tumour cells towards CSCs can occur, and therefore the CSC population in a neoplasm is expected to vary over time. Moreover, evidence suggests that not all tumours are driven by rare CSCs, but might instead contain a large population of tumorigenic cells. Even though these results suggest that specific targeting of the CSC population might not be a useful therapeutic strategy, research into the hierarchical cellular organisation of malignancies has provided many important new insights in the biology of tumours. In this Personal View, we highlight how the CSC concept is developing and influences our thinking on future treatment for solid tumours, and recommend ways to design clinical trials to assess drugs that target malignant disease in a rational fashion.

Validation of serum amyloid α as an independent biomarker for progression-free and overall survival in metastatic renal cell cancer patients.

BACKGROUND: We recently identified apolipoprotein A2 (ApoA2) and serum amyloid α (SAA) as independent prognosticators in metastatic renal cell carcinoma (mRCC) patients, thereby improving the accuracy of the Memorial-Sloan Kettering Cancer Center (MSKCC) model. OBJECTIVE: Validate these results prospectively in a separate cohort of mRCC patients treated with tyrosine kinase inhibitors (TKIs). DESIGN, SETTING, AND PARTICIPANTS: For training we used 114 interferon-treated mRCC patients (inclusion 2001-2006). For validation we studied 151 TKI-treated mRCC patients (inclusion 2003-2009). MEASUREMENTS: Using Cox proportional hazards regression analysis, SAA and ApoA2 were associated with progression-free survival (PFS) and overall survival (OS). In 72 TKI-treated patients, SAA levels were analyzed longitudinally as a potential early marker for treatment effect. RESULTS AND LIMITATIONS: Baseline ApoA2 and SAA levels significantly predicted PFS and OS in the training and validation cohorts. Multivariate analysis identified SAA in both separate patient sets as a robust and independent prognosticator for PFS and OS. In contrast to our previous findings, ApoA2 interacted with SAA in the validation cohort and did not contribute to a better predictive accuracy than SAA alone and was therefore excluded from further analysis. According to the tertiles of SAA levels, patients were categorized in three risk groups, demonstrating accurate risk prognostication. SAA as a single biomarker showed equal prognostic accuracy when compared with the multifactorial MSKCC risk mode. Using receiver operating characteristic analysis, SAA levels >71 ng/ml were designated as the optimal cut-off value in the training cohort, which was confirmed for its significant sensitivity and specificity in the validation cohort. Applying SAA >71 ng/ml as an additional risk factor significantly improved the predictive accuracy of the MSKCC model in both independent cohorts. Changes in SAA levels after 6-8 wk of TKI treatment had no value in predicting treatment outcome. CONCLUSIONS: SAA but not ApoA2 was shown to be a robust and independent prognosticator for PFS and OS in mRCC patients. When incorporated in the MSKCC model, SAA showed additional prognostic value for patient management.

Phase I and pharmacokinetic study of capecitabine and the oral mTOR inhibitor everolimus in patients with advanced solid malignancies.

BACKGROUND: Everolimus is an oral mTOR-inhibitor. Preclinical data show synergistic effects of mTOR inhibition in combination with 5-fluorouracil-based anticancer therapy. The combination of everolimus with capecitabine seems therefore an attractive new, orally available, treatment regimen. PATIENTS AND METHODS: Safety, preliminary efficacy and pharmacokinetics of everolimus in combination with capecitabine were investigated in patients with advanced solid malignancies. Patients were treated with fixed dose everolimus 10 mg/day continuously, plus capecitabine bid for 14 days in three-weekly cycles. Dose escalation of capecitabine proceeded according to the standard 3 × 3 phase I design in four predefined dose levels (500-1,000 mg/m(2) bid). RESULTS: In total, 18 patients were enrolled. Median (range) treatment duration with everolimus was 70 days (21-414). Capecitabine 1,000 mg/m(2) bid combined with 10 mg/day everolimus was declared the maximum tolerated dose, at which level one patient developed dose-limiting toxicity (stomatitis grade 3). Drug-related adverse events were mostly grade ≤ 2 and included mainly fatigue (56%), stomatitis (50%), and hand-foot syndrome (33%). Partial response was documented in three patients, and four had stable disease. There was no pharmacokinetic interaction between everolimus and capecitabine. CONCLUSION: Everolimus 10 mg/day continuously combined with capecitabine 1,000 mg/m(2) bid for 14 days every 3 weeks is a patient-convenient, safe and tolerable oral treatment regimen. This is the first study to demonstrate feasibility of this combination at doses with proven single agent efficacy in a number of tumors. Prolonged clinical benefit was observed in an encouraging 39% of patients with advanced solid malignancies.

5-Aminosalicylic acid inhibits cell cycle progression in a phospholipase D dependent manner in colorectal cancer.

BACKGROUND: 5-Aminosalicylic acid (5-ASA) may protect against the development of inflammation-associated colorectal cancer. In vitro data suggest that, in colorectal cancer cells, 5-ASA induces cell cycle arrest, but the molecular mechanism leading to this arrest remains to be determined. AIM: To dissect the signal transduction events that lead to 5-ASA mediated inhibition of proliferation of colorectal cancer cells, focusing on mammalian target of rapamycin (mTOR), a regulator of cell cycle progression. METHODS: The influence of 5-ASA on mTOR signalling was examined in a panel of colorectal cancer cell lines. The effects of 5-ASA on the pathways that control mTOR activity were studied in detail in two different colorectal cancer cell lines, using western blot, siRNA, a phospholipase D (PLD) activity assay, proliferation assays and cell cycle analysis. The phosphorylation status of mTOR and its downstream target, ribosomal protein S6, was studied in colorectal cancers before and after topical 5-ASA treatment. RESULTS: Treatment of colorectal cancer with 5-ASA inhibited mTOR signalling in vitro and in vivo. 5-ASA had no effect on any of the pathways that regulate the activity of the tuberous sclerosis complex in colorectal cancer cells. Both proliferation and mTOR activity depended on PLD, an enzyme that generates phosphatidic acid (PA). 5-ASA treatment inhibited PLD activity and proliferation; these effects could be rescued with exogenous PA. CONCLUSION: 5-ASA interferes with proliferation of colorectal cancer cells via inhibition of PLD-dependent generation of PA and loss of mTOR signalling.

Methylation of cancer-stem-cell-associated Wnt target genes predicts poor prognosis in colorectal cancer patients.

Gene signatures derived from cancer stem cells (CSCs) predict tumor recurrence for many forms of cancer. Here, we derived a gene signature for colorectal CSCs defined by high Wnt signaling activity, which in agreement with previous observations predicts poor prognosis. Surprisingly, however, we found that elevated expression of Wnt targets was actually associated with good prognosis, while patient tumors with low expression of Wnt target genes segregated with immature stem cell signatures. We discovered that several Wnt target genes, including ASCL2 and LGR5, become silenced by CpG island methylation during progression of tumorigenesis, and that their re-expression was associated with reduced tumor growth. Taken together, our data show that promoter methylation of Wnt target genes is a strong predictor for recurrence of colorectal cancer, and suggest that CSC gene signatures, rather than reflecting CSC numbers, may reflect differentiation status of the malignant tissue.

Model-based, semiquantitative and time intensity curve shape analysis of dynamic contrast-enhanced MRI: a comparison in patients undergoing antiangiogenic treatment for recurrent glioma.

PURPOSE: To compare time intensity curve (TIC)-shape analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data with model-based analysis and semiquantitative analysis in patients with high-grade glioma treated with the antiangiogenic drug bevacizumab. MATERIALS AND METHODS: Fifteen patients had a pretreatment and at least one posttreatment DCE-MRI. We applied a pixel-by-pixel TIC shape analysis, where TICs are classified into five different types according to their shape, and calculated the occurrence of each TIC type in the region of interest (ROI). The results were compared to the pharmacokinetic model (PKM) parameters K(trans) , K(ep) , V(e) , and V(i) , and with the semiquantitative parameters maximum enhancement (ME) and initial slope of increase (ISI). RESULTS: The relative amount of type 2 and 4 TIC shape significantly correlated with the parameter K(ep) but not with K(trans) or V(e) . The PKM parameter V(e) and the semiquantitative parameters ME and ISI showed significant changes after treatment. None of the TIC shapes individually showed significant changes. CONCLUSION: The semiquantitative parameters ME and ISI are more sensitive to the effect of the bevacizumab than K(trans) and V(e) . The pixel-by-pixel TIC shape analysis parameters are not sensitive to the effect of bevacizumab, although they can be seen as surrogates for the PKM parameter K(ep) .

Neoadjuvant chemoradiotherapy has a potential role in pancreatic carcinoma.

Pancreatic cancer has an extremely poor prognosis, only a small minority of patients undergo a resection with curative intent. Chemotherapy and/or radiochemotherapy may improve this by prolonging survival or disease-free interval and improving resectability and the proportion of microscopically complete (R0) resections. With regard to prolonging survival, both in the postoperative adjuvant setting and in locally advanced disease, chemotherapy has a positive but limited effect on survival and may be considered standard. The role of postoperative adjuvant radiochemotherapy remains debatable. For improving resectability/proportion of R0 resections, many studies suggest that the proportion of patients undergoing a resection during exploration and the proportion of R0 resections increase after neoadjuvant radiochemotherapy. This may improve the prognosis of patients with a resectable or borderline resectable pancreatic carcinoma. The effect of neoadjuvant radiochemotherapy, if any, is modest. The search for better combinations, including targeted therapy, must continue. The interpretation of single-arm studies is hampered by (selection) biases. The reporting of pathology and study endpoints should be internationally standardized. To avoid biases in studies of patients with (borderline) resectable tumours, prospective parallel registration of all patients referred for surgery would help. Ultimately, randomized controlled phase III trials should establish the role of neoadjuvant radiochemotherapy. Thus, neoadjuvant radiochemotherapy has a potential benefit in resectable and borderline resectable pancreatic cancer, but better combinations are warranted.

Vascular endothelial growth factor in the circulation in cancer patients may not be a relevant biomarker.

BACKGROUND: Levels of circulating vascular endothelial growth factor (VEGF) have widely been used as biomarker for angiogenic activity in cancer. For this purpose, non-standardized measurements in plasma and serum were used, without correction for artificial VEGF release by platelets activated ex vivo. We hypothesize that "true" circulating (c)VEGF levels in most cancer patients are low and unrelated to cancer load or tumour angiogenesis. METHODOLOGY: We determined VEGF levels in PECT, a medium that contains platelet activation inhibitors, in citrate plasma, and in isolated platelets in 16 healthy subjects, 18 patients with metastatic non-renal cancer (non-RCC) and 12 patients with renal cell carcinoma (RCC). In non-RCC patients, circulating plasma VEGF levels were low and similar to VEGF levels in controls if platelet activation was minimized during the harvest procedure by PECT medium. In citrate plasma, VEGF levels were elevated in non-RCC patients, but this could be explained by a combination of increased platelet activation during blood harvesting, and by a two-fold increase in VEGF content of individual platelets (controls: 3.4 IU/10(6), non-RCC: 6.2 IU/10(6) platelets, p = 0.001). In contrast, cVEGF levels in RCC patients were elevated (PECT plasma: 64 pg/ml vs. 21 pg/ml, RCC vs. non-RCC, p<0.0001), and not related to platelet VEGF concentration. CONCLUSIONS: Our findings suggest that "true" freely cVEGF levels are not elevated in the majority of cancer patients. Previously reported elevated plasma VEGF levels in cancer appear to be due to artificial release from activated platelets, which in cancer have an increased VEGF content, during the blood harvest procedure. Only in patients with RCC, which is characterized by excessive VEGF production due to a specific genetic defect, were cVEGF levels elevated. This observation may be related to limited and selective success of anti-VEGF agents, such as bevacizumab and sorafenib, as monotherapy in RCC compared to other forms of cancer.