[The development of a rational national MDMA policy and its relevance for psychiatry]. / Voorstel voor rationeel MDMA-beleid.

BACKGROUND: MDMA (ecstasy) is a relatively safe drug and induces little dependence, but is nevertheless scheduled as a hard drug (Dutch Opium Act, List 1). Concerns about MDMA-related crime, health incidents and possible inappropriate listing of MDMA on List I have led to an ongoing debate about current Dutch ecstasy policy. AIM: To develop a rational MDMA policy that takes into account all aspects related to production, sale and use of MDMA. METHOD: An interdisciplinary group of 18 experts formulates a science-based MDMA policy by assessing the expected effects of 95 policy options on 25 outcomes, including health, crime, law enforcement and finance. The optimal policy model consists of the combination of the 22 policy options with the highest total score on all 25 outcomes. RESULTS: The optimal policy model consisted of a form of regulated production and sale of MDMA, better quality management of ecstasy tablets and more intensive fight against MDMA-related organized crime. Such a policy would lead to a small increase in the prevalence of ecstasy use, but with less health damage, less MDMA-related crime, and less environmental damage. To increase practicality and political feasibility, the optimal model was slightly modified. CONCLUSION: The developed optimal model offers a politically and socially feasible set of policy instrument options, with which the placement of MDMA on List I can be revised, thereby reducing the damage of MDMA to users and society. For psychiatry, it means promoting therapeutic research and less nuisance from unnecessary stigmatization in the treatment of patients.

Targeting telomerase for its advent in cancer therapeutics.

Telomerase has emerged as an important primary target in anticancer therapy. It is a distinctive reverse transcriptase enzyme, which extends the length of telomere at the 3' chromosomal end, and uses telomerase reverse transcriptase (TERT) and telomerase RNA template-containing domains. Telomerase has a vital role and is a contributing factor in human health, mainly affecting cell aging and cell proliferation. Due to its unique feature, it ensures unrestricted cell proliferation in malignancy and plays a major role in cancer disease. The development of telomerase inhibitors with increased specificity and better pharmacokinetics is being considered to design and develop newer potent anticancer agents. Use of natural and synthetic compounds for the inhibition of telomerase activity can lead to an opening of new vistas in cancer treatment. This review details about the telomerase biochemistry, use of natural and synthetic compounds; vaccines and oncolytic virus in therapy that suppress the telomerase activity. We have discussed structure-activity relationships of various natural and synthetic telomerase inhibitors to help medicinal chemists and chemical biology researchers with a ready reference and updated status of their clinical trials. Suppression of human TERT (hTERT) activity through inhibition of hTERT promoter is an important approach for telomerase inhibition.

Never let it go: Stopping key mechanisms underlying metastasis to fight pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive neoplasm, predicted to become the second leading cause of cancer-related deaths before 2030. This dismal trend is mainly due to lack of effective treatments against its metastatic behavior. Therefore, a better understanding of the key mechanisms underlying metastasis should provide new opportunities for therapeutic purposes. Genomic analyses revealed that aberrations that fuel PDAC tumorigenesis and progression, such as SMAD4 loss, are also implicated in metastasis. Recently, microRNAs have been shown to play a regulatory role in the metastatic behavior of many tumors, including PDAC. In particular, miR-10 and miR-21 have appeared as master regulators of the metastatic program, while members of the miR-200 family are involved in the epithelial-to-mesenchymal switch, favoring cell migration and invasiveness. Several studies have also found a close relationship between cancer stem cells (CSCs) and biological features of metastasis, and the CSC markers ALDH1, ABCG2 and c-Met are expressed at high levels in metastatic PDAC cells. Emerging evidence reveals that exosomes are involved in the modulation of the tumor microenvironment and can initiate PDAC pre-metastatic niche formation in the liver and lungs. In this review, we provide an overview of the role of all these pivotal factors in the metastatic behavior of PDAC, and discuss their potential exploitation in the clinic to improve current therapeutics and identify new drug targets.

Role of proton-coupled folate transporter in pemetrexed resistance of mesothelioma: clinical evidence and new pharmacological tools.

BACKGROUND: Thymidylate synthase (TS) has a predictive role in pemetrexed treatment of mesothelioma; however, additional chemoresistance mechanisms are poorly understood. Here, we explored the role of the reduced-folate carrier (RFC/SLC19A1) and proton-coupled folate transporter (PCFT/SLC46A1) in antifolate resistance in mesothelioma. PATIENTS AND METHODS: PCFT, RFC and TS RNA and PCFT protein levels were determined by quantitative RT-PCR of frozen tissues and immunohistochemistry of tissue-microarrays, respectively, in two cohorts of pemetrexed-treated patients. Data were analyzed by t-test, Fisher's/log-rank test and Cox proportional models. The contribution of PCFT expression and PCFT-promoter methylation to pemetrexed activity were evaluated in mesothelioma cells and spheroids, through 5-aza-2'-deoxycytidine-mediated demethylation and siRNA-knockdown. RESULTS: Pemetrexed-treated patients with low PCFT had significantly lower rates of disease control, and shorter overall survival (OS), in both the test (N = 73, 11.3 versus 20.1 months, P = 0.01) and validation (N = 51, 12.6 versus 30.3 months, P = 0.02) cohorts. Multivariate analysis confirmed PCFT-independent prognostic role. Low-PCFT protein levels were also associated with shorter OS. Patients with both low-PCFT and high-TS levels had the worst prognosis (OS, 5.5 months), whereas associations were neither found for RFC nor in pemetrexed-untreated patients. PCFT silencing reduced pemetrexed sensitivity, whereas 5-aza-2'-deoxycytidine overcame resistance. CONCLUSIONS: These findings identify for the first time PCFT as a novel mesothelioma prognostic biomarker, prompting prospective trials for its validation. Moreover, preclinical data suggest that targeting PCFT-promoter methylation might eradicate pemetrexed-resistant cells characterized by low-PCFT expression.

Nitric oxide releasing acridone carboxamide derivatives as reverters of doxorubicin resistance in MCF7/Dx cancer cells.

A series of nitric oxide donating acridone derivatives are synthesized and evaluated for in vitro cytotoxic activity against different sensitive and resistant cancer cell lines MCF7/Wt, MCF7/Mr (BCRP overexpression) and MCF7/Dx (P-gp expression). The results showed that NO-donating acridones are potent against both the sensitive and resistant cells. Structure activity relationship indicate that the nitric oxide donating moiety connected through a butyl chain at N(10) position as well as morpholino moiety linkage through an amide bridge on the acridone ring system at C-2 position, are required to exert a good cytotoxic effect. Further, good correlations were observed when cytotoxic properties were compared with in vitro nitric oxide release rate, nitric oxide donating group potentiated the cytotoxic effect of the acridone derivatives. Exogenous release of nitric oxide by NO donating acridones enhanced the accumulation of doxorubicin in MCF7/Dx cell lines when it was coadministered with doxorubicin, which inhibited the efflux process of doxorubicin. In summary, a nitric oxide donating group can potentiate the anti-MDR property of acridones.

Tailoring heated intraperitoneal mitomycin C for peritoneal metastases originating from colorectal carcinoma: a translational approach to improve survival.

BACKGROUND: Patients with peritoneal metastases (PMs) originating from colorectal carcinoma (CRC) are curatively treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) with mitomycin C (MMC). We aim to improve patient selection for HIPEC by predicting MMC sensitivity. METHODS: The MMC sensitivity was determined for 12 CRC cell lines and correlated to mRNA expression of 37 genes related to the Fanconi anaemia (FA)-BRCA pathway, ATM-ATR pathway and enzymatic activation of MMC. Functionality of the FA-BRCA pathway in cell lines was assessed using a chromosomal breakage assay and western blot for key protein FANCD2. Bloom syndrome protein (BLM) was further analysed by staining for the corresponding protein with immunohistochemistry (IHC) on both CRC cell lines (n=12) and patient material (n=20). RESULTS: High sensitivity correlated with a low BLM (P=0.01) and BRCA2 (P=0.02) at mRNA expression level. However, FA-BRCA pathway functionality demonstrated no correlation to MMC sensitivity. In cell lines, weak intensity staining of BLM by IHC correlated to high sensitivity (P=0.04) to MMC. Low BLM protein expression was significantly associated with an improved survival in patients after CRS and HIPEC (P=0.04). CONCLUSIONS: Low BLM levels are associated with high MMC sensitivity and an improved survival after HIPEC.

Synergistic interaction of novel lactate dehydrogenase inhibitors with gemcitabine against pancreatic cancer cells in hypoxia.

BACKGROUND: Hypoxia is a driving force in pancreatic-ductal-adenocarcinoma (PDAC) growth, metastasis and chemoresistance. The muscle-isoform of lactate dehydrogenase (LDH-A) constitutes a major checkpoint for the switch to anaerobic glycolysis, ensuring supply of energy and anabolites in hypoxic-environments. Therefore, we investigated the molecular mechanisms underlying the pharmacological interaction of novel LDH-A inhibitors in combination with gemcitabine in PDAC cells. METHODS: Lactate dehydrogenase A levels were studied by quantitative RT-PCR, western blot, immunofluorescence and activity assays in 14 PDAC cells, including primary-cell-cultures and spheroids, in normoxic and hypoxic conditions. Cell proliferation, migration and key determinants of drug activity were evaluated by sulforhodamine-B-assay, wound-healing assay, PCR and LC-MS/MS. RESULTS: Lactate dehydrogenase A was significantly increased under hypoxic conditions (1% O2), where the novel LDH-A inhibitors proved to be particularly effective (e.g., with IC50 values of 0.9 vs 16.3 µM for NHI-1 in LPC006 in hypoxia vs normoxia, respectively). These compounds induced apoptosis, affected invasiveness and spheroid-growth, reducing expression of metalloproteinases and cancer-stem-like-cells markers (CD133+). Their synergistic interaction with gemcitabine, with combination index values <0.4 in hypoxia, might also be attributed to modulation of gemcitabine metabolism, overcoming the reduced synthesis of phosphorylated metabolites. CONCLUSION: Lactate dehydrogenase A is a viable target in PDAC, and novel LDH-A inhibitors display synergistic cytotoxic activity with gemcitabine, offering an innovative tool in hypoxic tumours.

The good, the bad and the ugly: a tale of miR-101, miR-21 and miR-155 in pancreatic intraductal papillary mucinous neoplasms.

BACKGROUND: This multicenter study evaluated three candidate microRNAs (miRNAs) (miR-21, miR-155 and miR-101) as potential biomarkers in intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. PATIENTS AND METHODS: miRNA expression was quantified by quantitative RT-PCR in 86 laser-microdissected specimens, including 65 invasive IPMNs, 16 non-invasive IPMNs and 5 normal pancreatic ductal tissues. Univariate and multivariate analyses compared miRNAs and clinical parameters with overall (OS) and disease-free survival (DFS). RESULTS: miR-21 and miR-155 were up-regulated in invasive IPMNs compared with non-invasive IPMNs, as well as in non-invasive IPMNs compared with normal tissues. Conversely, miR-101 levels were significantly higher in non-invasive IPMNs and normal tissues compared with invasive IPMNs. High levels of miR-21 were associated with worse OS [hazard ratio (HR) = 2.47, 95% confidence interval (CI) = 1.37-5.65, P = 0.0047]. Patients with high-miR-21 expression also had a shorter median DFS (10.9 versus 29.9 months, P = 0.01). Multivariate analysis confirmed miR-21 as independently prognostic for mortality and disease progression (death risk: HR = 3.3, 95% CI = 1.5-7.0, P = 0.02; progression risk: HR = 2.3, 95% CI = 1.2-4.8, P = 0.02), as well as positive lymph-node status (death risk: HR = 2.6, 95% CI = 1.1-6.3, P = 0.03; progression risk: HR = 2.2, 95% CI = 1.0-4.8, P = 0.04). CONCLUSIONS: miR-21, miR-155 and miR-101 showed significant differences in invasive versus non-invasive IPMNs. miR-21 emerged as an independent prognostic biomarker in invasive IPMNs and should be validated in prospective studies.

Ageing with an intellectual disability: the impact of personal resources on well-being.

BACKGROUND: The population of ageing people with mild and moderate intellectual disabilities (ID) is growing rapidly. This study examines how personal resources (physical health, mental health and social networks) impact the well-being of ageing people with ID. METHODS: Longitudinal survey data on 667 people with a mild or moderate ID were acquired via interviews in 2006 and 2010. Indicators of personal resources (physical health, mental health and social networks) were assessed, as were indicators of well-being (satisfaction with life, happiness and loneliness). Additionally, data on background characteristics and autonomy were gathered. RESULTS: The results show that age is positively related to decreased mobility and auditory disabilities and negatively related to independent living, autonomy in how one spends one's leisure time and autonomy in decision-making. Longitudinal analyses demonstrated that, with the exception of health that deteriorated, and social satisfaction that improved, almost all variables remained stable over the 4-year period. Further, good physical health in 2006 predicted happiness in 2010. CONCLUSION: Despite the fact that age is associated with poorer physical and mental health and a smaller social network, this study showed that older people with ID have relatively high levels of well-being. Findings are discussed in the light of coping with ageing and impact of life events.

Radio-sensitizing effect of MEK inhibition in glioblastoma in vitro and in vivo.

INTRODUCTION: Glioblastoma (GBM) is an incurable cancer type. New therapeutic options are investigated, including targeting the mitogen-activated protein kinase (MAPK) pathway using MEK inhibitors as radio-sensitizers. In this study, we investigated whether MEK inhibition via PD0325901 leads to radio-sensitization in experimental in vitro and in vivo models of GBM. MATERIALS AND METHODS: In vitro, GBM8 multicellular spheroids were irradiated with 3 fractions of 2 Gy, during 5 consecutive days of incubation with either PD0325901 or MEK-162. In vivo, we combined PD0325901 with radiotherapy in the GBM8 orthotopic mouse model, tumor growth was measured weekly by bioluminescence imaging and overall survival and toxicity were assessed. RESULTS: Regrowth and viability of spheroids monitored until day 18, showed that both MEK inhibitors had an in vitro radio-sensitizing effect. In vivo, PD0325901 concentrations were relatively constant throughout multiple brain areas and temporal PD0325901-related adverse events such as dermatitis were observed in 4 out of 14 mice (29%). Mice that were treated with radiation alone or combined with PD0325901 had significantly better survival compared to vehicle (both P < 0.005), however, no significant interaction between PD0325901 MEK inhibition and irradiation was observed. CONCLUSION: The difference between the radiotherapy-enhancing effect of PD0325901 in vitro and in vivo urges further pharmacodynamic/pharmacokinetic investigation of PD0325901 and possibly other candidate MEK inhibitors.

Correlation of cytidine deaminase polymorphisms and activity with clinical outcome in gemcitabine-/platinum-treated advanced non-small-cell lung cancer patients.

BACKGROUND: The aim of this study was to evaluate whether cytidine deaminase (CDA) polymorphisms 79A>C and 435C>T and/or CDA enzymatic activity influenced clinical outcome in 126 advanced non-small-cell lung cancer patients treated with gemcitabine-platinum-regimens. PATIENTS AND METHODS: CDA polymorphisms and activity were analysed by PCR and high-performance liquid chromatography, respectively. Univariate and multivariate analyses compared biological/clinical parameters with response, clinical benefit, time to progression (TtP) and overall survival (OS) using Pearson's χ(2) test, log-rank test and Cox proportional hazards model. RESULTS: Patients with CDA A79A/A79C genotypes had significantly longer TtP (6.0 versus 3.0 months; P = 0.001) and OS (11.0 versus 5.0 months; P = 0.001) than patients with C79C genotype. Patients harbouring CDA C435C/C435T genotypes also had a longer OS (P = 0.025), but no correlations were observed with TtP. Conversely, patients with low-CDA activity had a significantly higher response rate (37.7% versus 13.8%; P = 0.006), clinical benefit (91.8% versus 51.7%; P < 0.001), as well as longer TtP (8.0 versus 3.0 months; P < 0.001) and OS (19.0 versus 6.0 months; P < 0.001). Furthermore, enzymatic activity emerged as an independent predictor for death/progression risk at multivariate analysis. CONCLUSIONS: CDA enzymatic activity appears to be the strongest candidate biomarker of activity and efficacy of platinum-gemcitabine-based chemotherapy and should be validated in a prospective study.

A comprehensive review on acridone based derivatives as future anti-cancer agents and their structure activity relationships.

The development of drug resistance and severe side-effects has reduced the clinical efficacy of the existing anti-cancer drugs available in the market. Thus, there is always a constant need to develop newer anti-cancer drugs with minimal adverse effects. Researchers all over the world have been focusing on various alternative strategies to discover novel, potent, and target specific molecules for cancer therapy. In this direction, several heterocyclic compounds are being explored but amongst them one promising heterocycle is acridone which has attracted the attention of medicinal chemists and gained huge biological importance as acridones are found to act on different therapeutically proven molecular targets, overcome ABC transporters mediated drug resistance and DNA intercalation in cancer cells. Some of these acridone derivatives have reached clinical studies as these heterocycles have shown huge potential in cancer therapeutics and imaging. Here, the authors have attempted to compile and make some recommendations of acridone based derivatives concerning their cancer biological targets and in vitro-cytotoxicity based on drug design and novelty to increase their therapeutic potential. This review also provides some important insights on the design, receptor targeting and future directions for the development of acridones as possible clinically effective anti-cancer agents.

The semisynthetic flavonoid monoHER sensitises human soft tissue sarcoma cells to doxorubicin-induced apoptosis via inhibition of nuclear factor-κB.

BACKGROUND: Despite therapeutic advances, the prognosis of patients with metastatic soft tissue sarcoma (STS) remains extremely poor. The results of a recent clinical phase II study, evaluating the protective effects of the semisynthetic flavonoid 7-mono-O-(ß-hydroxyethyl)-rutoside (monoHER) on doxorubicin-induced cardiotoxicity, suggest that monoHER enhances the antitumour activity of doxorubicin in STSs. METHODS: To molecularly explain this unexpected finding, we investigated the effect of monoHER on the cytotoxicity of doxorubicin, and the potential involvement of glutathione (GSH) depletion and nuclear factor-κB (NF-κB) inactivation in the chemosensitising effect of monoHER. RESULTS: MonoHER potentiated the antitumour activity of doxorubicin in the human liposarcoma cell line WLS-160. Moreover, the combination of monoHER with doxorubicin induced more apoptosis in WLS-160 cells compared with doxorubicin alone. MonoHER did not reduce intracellular GSH levels. On the other hand, monoHER pretreatment significantly reduced doxorubicin-induced NF-κB activation. CONCLUSION: These results suggest that reduction of doxorubicin-induced NF-κB activation by monoHER, which sensitises cancer cells to apoptosis, is involved in the chemosensitising effect of monoHER in human liposarcoma cells.

Thymidine phosphorylase in cancer cells stimulates human endothelial cell migration and invasion by the secretion of angiogenic factors.

BACKGROUND: Thymidine phosphorylase (TP) is often overexpressed in tumours and has a role in tumour aggressiveness and angiogenesis. Here, we determined whether TP increased tumour invasion and whether TP-expressing cancer cells stimulated angiogenesis. METHODS: Angiogenesis was studied by exposing endothelial cells (HUVECs) to conditioned medium (CM) derived from cancer cells with high (Colo320TP1=CT-CM, RT112/TP=RT-CM) and no TP expression after which migration (wound-healing-assay) and invasion (transwell-assay) were determined. The involvement of several angiogenic factors were examined by RT-PCR, ELISA and blocking antibodies. RESULTS: Tumour invasion was not dependent on intrinsic TP expression. The CT-CM and RT-CM stimulated HUVEC-migration and invasion by about 15 and 40%, respectively. Inhibition by 10 µM TPI and 100 µM L-dR, blocked migration and reduced the invasion by 50-70%. Thymidine phosphorylase activity in HUVECs was increased by CT-CM. Reverse transcription-polymerase chain reaction revealed a higher mRNA expression of bFGF (Colo320TP1), IL-8 (RT112/TP) and TNF-α, but not VEGF. Blocking antibodies targeting these factors decreased the migration and invasion that was induced by the CT-CM and RT-CM, except for IL-8 in CT-CM and bFGF in RT-CM. CONCLUSION: In our cell line panels, TP did not increase the tumour invasion, but stimulated the migration and invasion of HUVECs by two different mechanisms. Hence, TP targeting seems to provide a potential additional strategy in the field of anti-angiogenic therapy.

Preclinical emergence of vandetanib as a potent antitumour agent in mesothelioma: molecular mechanisms underlying its synergistic interaction with pemetrexed and carboplatin.

BACKGROUND: Although pemetrexed, a potent thymidylate synthase (TS) inhibitor, enhances the cytoytoxic effect of platinum compounds against malignant pleural mesothelioma (MPM), novel combinations with effective targeted therapies are warranted. To this end, the current study evaluates new targeted agents and their pharmacological interaction with carboplatin-pemetrexed in human MPM cell lines. METHODS: We treated H2052, H2452, H28 and MSTO-211H cells with carboplatin, pemetrexed and targeted compounds (gefitinib, erlotinib, sorafenib, vandetanib, enzastaurin and ZM447439) and evaluated the modulation of pivotal pathways in drug activity and cancer cell proliferation. RESULTS: Vandetanib emerged as the compound with the most potent cytotoxic activity, which interacted synergistically with carboplatin and pemetrexed. Drug combinations blocked Akt phosphorylation and increased apoptosis. Vandetanib significantly downregulated epidermal growth factor receptor (EGFR)/Erk/Akt phosphorylation as well as E2F-1 mRNA and TS mRNA/protein levels. Moreover, pemetrexed decreased Akt phosphorylation and expression of DNA repair genes. Finally, most MPM samples displayed detectable levels of EGFR and TS, the variability of which could be used for patients' stratification in future trials with vandetanib-pemetrexed-carboplatin combination. CONCLUSION: Vandetanib markedly enhances pemetrexed-carboplatin activity against human MPM cells. Induction of apoptosis, modulation of EGFR/Akt/Erk phosphorylation and expression of key determinants for pemetrexed and carboplatin activity contribute to this synergistic interaction, and, together with the expression of these determinants in MPM samples, warrant further clinical investigation.

Sorafenib administered using a high-dose, pulsatile regimen in patients with advanced solid malignancies: a phase I exposure escalation study.

BACKGROUND: (Pre)clinical evidence is accumulating that intermittent exposure to increased doses of protein kinase inhibitors may improve their treatment benefit. In this phase I trial, the safety of high-dose, pulsatile sorafenib was studied. PATIENTS AND METHODS: High-dose sorafenib was administered once weekly in exposure escalation cohorts according to a 3 + 3 design. Drug monitoring was performed in weeks 1-3 and doses were adjusted to achieve a predefined target plasma area under the curve (AUC)(0-12 h). The effect of low gastric pH on improving sorafenib exposure was investigated by intake of the acidic beverage cola. RESULTS: Seventeen patients with advanced malignancies without standard treatment options were included. Once weekly, high-dose sorafenib exposure was escalated up to a target AUC(0-12 h) of 125-150 mg/L/h, achieving a twofold higher Cmax compared to standard continuous dosing. Dose-limiting toxicity was observed in three patients: grade 3 duodenal perforation (2800 mg sorafenib), grade 5 multiorgan failure (2800 mg sorafenib) and grade 5 biliary tract perforation (3600 mg sorafenib). The mean difference between observed and target AUC(0-12 h) was 45% (SD ± 56%) in week 1 using a fixed starting dose of sorafenib compared to 2% (SD ± 32%) in week 3 as a result of drug monitoring (P = 0.06). Dissolving sorafenib in cola, instead of water, did not improve sorafenib exposure. Clinical benefit with stable disease as the best response was observed in two patients. CONCLUSION: Treatment with high-dose, once weekly sorafenib administration resulted in dose-limiting toxicity precluding dose escalation above the exposure cohort of 125-150 mg/L/h. Drug monitoring was a successful strategy to pursue a target exposure.

Impact of cellular folate status and epidermal growth factor receptor expression on BCRP/ABCG2-mediated resistance to gefitinib and erlotinib.

The effect of folate status on breast cancer resistance protein (BCRP)-mediated drug resistance to epidermal growth factor receptor (EGFR)-targeted drugs, such as gefitinib and erlotinib, was investigated in two human colon cancer cell lines, WiDr and Caco-2, of which the latter displayed greater sensitivity to these drugs due to high EGFR expression. Caco-2 LF/LV cells, growing under low-folate (LF) conditions, showed increased BCRP protein expression compared with the high-folate (HF) counterpart, which was associated with 1.8-fold resistance to gefitinib. Of note, the BCRP-specific inhibitor Ko143 completely reverted this phenotype. WiDr LF cells also showed slightly increased BCRP expression compared with the HF cells, but no differences in gefitinib sensitivity were observed. Both Caco-2 LF/LV and WiDr LF cells showed 2.4- and 2.3-fold resistance to erlotinib, respectively, compared with their HF counterparts, which mechanistically seemed BCRP unrelated, as Ko143 had no effect on erlotinib activity. In conclusion, our data suggest that in EGFR-expressing Caco-2 cells, BCRP is one of the determinants of gefitinib resistance but not of erlotinib resistance. Beyond this, folate depletion can provoke an additional decrease in gefitinib and erlotinib activity by mechanisms dependent or independent of BCRP modulation.

Combined assessment of EGFR pathway-related molecular markers and prognosis of NSCLC patients.

The purpose of this study is to evaluate the prognostic value of the combined assessment of multiple molecular markers related to the epidermal growth factor receptor (EGFR) pathway in resected non-small cell lung cancer (NSCLC) patients. Tumour specimens of 178 NSCLC patients were collected and analysed for EGFR and KRAS mutation status by DNA sequencing, and for EGFR copy number by fluorescent in situ hybridisation. Tissue microarrays were generated and used to determine the expression of multiple EGFR pathway-related proteins by immunohistochemistry. We analysed the association between each marker and patient prognosis. Univariate analyses for each clinical variable and each molecular marker were performed using Kaplan-Meier curves and log-rank tests. From these results, we selected the variables KRAS mutations and expression of cytoplasmic EGFR, granular pERK, nuclear pSTAT3, cytoplasmic E-cadherin and cytoplasmic pCMET to enter into a Cox proportional hazards model, along with stage as the strongest clinical variable related with prognosis. Of the EGFR-related markers evaluated here, the markers EGFR, pERK, pSTAT3, E-cadherin, pCMET and mutations in KRAS were associated with survival when analysed in combination in our patient cohort, with P=0.00015 as the P-value for a test of the additional impact of markers on prognosis, after taking stage into consideration. Confirmation of the impact of these markers in independent studies will be necessary.

DNA copy number profiles of primary tumors as predictors of response to chemotherapy in advanced colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is biologically a heterogeneous disease, which may affect response to drug therapy. We investigated the correlation of genome-wide DNA copy number profiles of primary tumors with response to systemic chemotherapy in advanced CRC. PATIENTS AND METHODS: DNA was isolated from formaldehyde-fixed paraffin-embedded primary tumors of 32 patients with advanced CRC, which were selected based on either a good response (n = 16) or a poor response (n = 16) to first-line combination therapy with capecitabine and irinotecan. High-resolution DNA copy number profiles were obtained by means of 30 K oligonucleotide-based array comparative genomic hybridization (aCGH). RESULTS: Unsupervised hierarchical cluster analysis of the aCGH data revealed two clusters of 19 and 13 tumors, respectively, and cluster membership showed a significant correlation with response status (P < 0.03). The nonresponders had fewer chromosomal alterations compared with the responders, in particular less losses were found (P < 0.03). Most prominent differences between the two groups were losses of regions 18p11.32-q11.2 (P < 0.02) and 18q12.1-q23 (P < 0.03), which were more frequently observed in responders. CONCLUSIONS: Differences in DNA copy number profiles of primary CRCs are associated with response to systemic combination chemotherapy with capecitabine and irinotecan. Responders overall had more chromosomal alterations, especially loss of chromosome 18.