The NORDIC-VII multicenter phase III trial investigated the efficacy of cetuximab when added to bolus fluorouracil/folinic acid and oxaliplatin (Nordic FLOX), administered continuously or ...intermittently, in previously untreated metastatic colorectal cancer (mCRC). The influence of KRAS mutation status on treatment outcome was also investigated.
Patients were randomly assigned to receive either standard Nordic FLOX (arm A), cetuximab and FLOX (arm B), or cetuximab combined with intermittent FLOX (arm C). Primary end point was progression-free survival (PFS). Overall survival (OS), response rate, R0 resection rate, and safety were secondary end points.
Of the 571 patients randomly assigned, 566 were evaluable in intention-to-treat (ITT) analyses. KRAS and BRAF mutation analyses were obtained in 498 (88%) and 457 patients (81%), respectively. KRAS mutations were present in 39% of the tumors; 12% of tumors had BRAF mutations. The presence of BRAF mutations was a strong negative prognostic factor. In the ITT population, median PFS was 7.9, 8.3, and 7.3 months for the three arms, respectively (not significantly different). OS was almost identical for the three groups (20.4, 19.7, 20.3 months, respectively), and confirmed response rates were 41%, 49%, and 47%, respectively. In patients with KRAS wild-type tumors, cetuximab did not provide any additional benefit compared with FLOX alone. In patients with KRAS mutations, no significant difference was detected, although a trend toward improved PFS was observed in arm B. The regimens were well tolerated.
Cetuximab did not add significant benefit to the Nordic FLOX regimen in first-line treatment of mCRC.
The aim was to explore the prognostic significance of IL-6 and markers of systemic inflammatory response (SIR), in particular C-reactive protein (CRP), in metastatic colorectal cancer (mCRC) ...patients, in the total study population and according to RAS and BRAF mutation status.
High levels of pretreatment serum IL-6 or CRP were associated with impaired outcome, in terms of reduced PFS and OS. Patients with low versus high serum IL-6 levels had median OS of 26.0 versus 16.6 months, respectively (P < 0.001). Stratified according to increasing CRP levels, median OS varied from 24.3 months to 12.3 months, (P < 0.001). IL-6 and CRP levels affected overall prognosis also in adjusted analyses. The effect of IL-6 was particularly pronounced in patients with BRAF mutation (interaction P = 0.004).
IL-6 and CRP were determined in pre-treatment serum samples from 393 patients included in the NORDIC-VII trial, in which patients with mCRC received first line treatment. The effect of serum IL-6 and CRP on progression-free survival (PFS) and overall survival (OS) was estimated.
High baseline serum consentrations of IL-6 or CRP were associated with impaired prognosis in mCRC. IL-6 and CRP give independent prognostic information in addition to RAS and BRAF mutation status.
Neurotensin has been found to promote colon carcinogenesis in rats and mice, and proliferation of human colon carcinoma cell lines, but the mechanisms involved are not clear. We have examined ...signalling pathways activated by neurotensin in colorectal and pancreatic carcinoma cells.
Colon carcinoma cell lines HCT116 and HT29 and pancreatic adenocarcinoma cell line Panc-1 were cultured and stimulated with neurotensin or epidermal growth factor (EGF). DNA synthesis was determined by incorporation of radiolabelled thymidine into DNA. Levels and phosphorylation of proteins in signalling pathways were assessed by Western blotting.
Neurotensin stimulated the phosphorylation of both extracellular signal-regulated kinase (ERK) and Akt in all three cell lines, but apparently did so through different pathways. In Panc-1 cells, neurotensin-induced phosphorylation of ERK, but not Akt, was dependent on protein kinase C (PKC), whereas an inhibitor of the β-isoform of phosphoinositide 3-kinase (PI3K), TGX221, abolished neurotensin-induced Akt phosphorylation in these cells, and there was no evidence of EGF receptor (EGFR) transactivation. In HT29 cells, in contrast, the EGFR tyrosine kinase inhibitor gefitinib blocked neurotensin-stimulated phosphorylation of both ERK and Akt, indicating transactivation of EGFR, independently of PKC. In HCT116 cells, neurotensin induced both a PKC-dependent phosphorylation of ERK and a metalloproteinase-mediated transactivation of EGFR that was associated with a gefitinib-sensitive phosphorylation of the downstream adaptor protein Shc. The activation of Akt was also inhibited by gefitinib, but only partly, suggesting a mechanism in addition to EGFR transactivation. Inhibition of PKC blocked neurotensin-induced DNA synthesis in HCT116 cells.
While acting predominantly through PKC in Panc-1 cells and via EGFR transactivation in HT29 cells, neurotensin used both these pathways in HCT116 cells. In these cells, neurotensin-induced activation of ERK and stimulation of DNA synthesis was PKC-dependent, whereas activation of the PI3K/Akt pathway was mediated by stimulation of metalloproteinases and subsequent transactivation of the EGFR. Thus, the data show that the signalling mechanisms mediating the effects of neurotensin involve multiple pathways and are cell-dependent.
It is important to understand the mechanisms by which the cells integrate signals from different receptors. Several lines of evidence implicate epidermal growth factor (EGF) receptor (EGFR) in the ...pathophysiology of hepatocarcinomas. Data also suggest a role of prostaglandins in some of these tumours, through their receptors of the G protein-coupled receptor (GPCR) family. In this study we have investigated mechanisms of interaction between signalling from prostaglandin receptors and EGFR in hepatocarcinoma cells.
The rat hepatocarcinoma cell line MH1C1 and normal rat hepatocytes in primary culture were stimulated with EGF or prostaglandin E2 (PGE2) and in some experiments also PGF2α. DNA synthesis was determined by incorporation of radiolabelled thymidine into DNA, phosphorylation of proteins in signalling pathways was assessed by Western blotting, mRNA expression of prostaglandin receptors was determined using qRT-PCR, accumulation of inositol phosphates was measured by incorporation of radiolabelled inositol, and cAMP was determined by radioimmunoassay.
In the MH1C1 hepatocarcinoma cells, stimulation with PGE2 or PGF2α caused phosphorylation of the EGFR, Akt, and ERK, which could be blocked by the EGFR tyrosine kinase inhibitor gefitinib. This did not occur in primary hepatocytes. qRT-PCR revealed expression of EP1, EP4, and FP receptor mRNA in MH1C1 cells. PGE2 stimulated accumulation of inositol phosphates but not cAMP in these cells, suggesting signalling via PLCβ. While pretreatment with EP1 and EP4 receptor antagonists did not inhibit the effect of PGE2, pretreatment with an FP receptor antagonist blocked the phosphorylation of EGFR, Akt and ERK. Further studies suggested that the PGE2-induced signal was mediated via Ca2+ release and not PKC activation, and that it proceeded through Src and shedding of membrane-bound EGFR ligand precursors by proteinases of the ADAM family.
The results indicate that in MH1C1 cells, unlike normal hepatocytes, PGE2 activates the MEK/ERK and PI3K/Akt pathways by transactivation of the EGFR, thus diversifying the GPCR-mediated signal. The data also suggest that the underlying mechanisms in these cells involve FP receptors, PLCβ, Ca2+, Src, and proteinase-mediated release of membrane-associated EGFR ligand(s).
Much effort is currently being spent on developing anticancer drugs targeted at cellular signal transduction mechanisms, and several signal inhibitors have also been introduced into clinical ...practice. The rationale for such therapy is the realization that, in general, oncogenes and tumour suppressor genes encode proteins that are mutated or dysregulated forms of key components in major regulatory pathways. However, while we have witnessed striking clinical effects in certain malignancies, as in the treatment of chronic myelogeneous leukemia, the results in many other cancers have been rather disappointing, and this has raised the question of whether major advances can realistically be expected by the use of signal-targeted therapies on a broad scale. Here we briefly review the cellular and molecular basis for treatment with pharmacological signal inhibitors and the clinical experience with their use in different malignancies. We also discuss general strategies to improve the treatment, including approaches to the problem of resistance development. Clinical results vary greatly, from little or no treatment success in some cancers to an increasing number of examples of very promising responses. Progress has primarily been achieved in those malignancies and subsets of patients where the underlying molecular mechanisms have been explored in detail and the targets have been well defined. In conclusion, it is likely that novel signal-directed approaches will lead to further important advances in cancer therapy, but this will require continued efforts to identify targets that are oncogenic determinants, and systematic work to select patients for more individualized therapies.
Prostaglandins stimulate hepatocyte proliferation in vivo and in vitro. We have examined the role of E prostanoid (EP) and F prostanoid receptors (FP) in enhancing the growth-stimulatory effect of ...epidermal growth factor (EGF) in cultured hepatocytes. The EP2 receptor agonist butaprost had no significant effect on EGF-induced DNA synthesis. EP1 receptor-selective antagonists did not affect the enhancement by prostaglandin E(2) of EGF-stimulated DNA synthesis. Sulprostone, misoprostol, and fluprostenol strongly enhanced DNA synthesis and inhibited glucagon-stimulated cAMP accumulation, indicating that they all activated EP3 receptors. Sulprostone and fluprostenol, and to a lesser extent misoprostol, stimulated accumulation of inositol phosphates. The effects of fluprostenol and sulprostone on phospholipase C (PLC) were inhibited by the FP receptor antagonist AL-8810 9 alpha, 15R-dihydroxy-11 beta-fluoro-15-(2,3-dihydro-1H-inden-2-yl)-16,17,18,19,20-pentanor-prosta-5Z, 13E-dien-1-oic acid, indicating that this effect was mediated by FP receptors. Inhibition of protein kinase C with GF109203X 2-1-(3-dimetylaminopropyl)-1H-indol-3-yl-maleimide resulted in a partial reduction of the growth stimulation induced by fluprostenol, indicating a minor role of FP receptors. Combining fluprostenol with misoprostol, but not with sulprostone, resulted in partially additive effects on DNA synthesis, suggesting that both EP3 and FP receptors are involved. Combining sulprostone with misoprostol did not result in additive effects on DNA synthesis, suggesting that EP4 receptors were not involved. We conclude that, although a minor effect is exerted by FP receptors, the growth-stimulatory effects of prostaglandins in rat hepatocytes are mediated mainly by EP3 receptors. We have found no evidence of EP1 receptor involvement.
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