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67 result(s) for "PAPANDREOU, CHRISTOS"
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Silencing of caveolin-1 in fibroblasts as opposed to epithelial tumor cells results in increased tumor growth rate and chemoresistance in a human pancreatic cancer model
Caveolin-1 (Cav-1) expression has been shown to be associated with tumor growth and resistance to chemotherapy in pancreatic cancer. The primary aim of this study was to explore the significance of Cav-1 expression in pancreatic cancer cells as compared to fibroblasts in relation to cancer cell proliferation and chemoresistance, both in vitro and in vivo, in an immunodeficient mouse model. We also aimed to evaluate the immunohistochemical expression of Cav-1 in the epithelial and stromal component of pancreatic cancer tissue specimens. The immunohistochemical staining of poorly differentiated tissue sections revealed a strong and weak Cav-1 expression in the epithelial tumor cells and stromal fibroblasts, respectively. Conversely, the well-differentiated areas were characterized by a weak epithelial Cav-1 expression. Cav-1 downregulation in cancer cells resulted in an increased proliferation in vitro; however, it had no effect on chemoresistance and growth gain in vivo. By contrast, the decreased expression of Cav-1 in fibroblasts resulted in a growth advantage and the chemo-resistance of cancer cells when they were co-injected into immunodeficient mice to develop mixed fibroblast/cancer cell xenografts. On the whole, the findings of this study suggest that the downregulation of Cav-1 in fibroblasts is associated with an increased tumor proliferation rate in vivo and chemoresistance. Further studies are warranted to explore whether the targeting of Cav-1 in the stroma may represent a novel therapeutic approach in pancreatic cancer.
Bortezomib represses HIF-1α protein expression and nuclear accumulation by inhibiting both PI3K/Akt/TOR and MAPK pathways in prostate cancer cells
Bortezomib represents the first proteasome inhibitor (PI) with demonstrated antitumor activity in the clinical setting, particularly for treatment of hematological malignancies. At the preclinical level, its action is shown to be mediated by induction of growth arrest and apoptosis in many tumor types, including androgen-dependent (AD) and androgen-independent (AI) prostate cancer (PCa) cells. Hypoxia-inducible factor-1α (HIF-1α), which is directly involved in tumor growth, is one of the most studied and promising molecular targets for anti-cancer therapy and is often overexpressed in PCa. Bortezomib has been reported to impair tumor growth by also inhibiting HIF-1α. In this study, we investigated the effect of bortezomib on the expression, activity and localization of HIF-1α in LNCaP (AD) and PC3 (AI) PCa cells. First, we show that hypoxic upregulation of HIF-1α protein levels and activity involves both the PI3K/Akt/mTOR and p44/42 MAPK pathways. Second, bortezomib inhibits expression of HIF-1α protein under both normoxic and hypoxic conditions, represses HIF-1 transcriptional activity and attenuates the release of vascular endothelial growth factor. These effects correlate with the ability of bortezomib to cause dephosphorylation of phospho-Akt, phospho-p70S6K, and phospho-S6RP, thus inactivating a pathway known to be required for HIF-1α protein expression at the translational level. Furthermore, bortezomib also abrogates p44/42 MAPK phosphorylation, which results to reduced nuclear translocation of HIF-1α. Taken together, these results suggest that bortezomib inhibits HIF-1α protein synthesis and its nuclear targeting through suppression of PI3K/Akt/mTOR and MAPK pathways, respectively, in both AD and AI PCa cells.
XELIRI-bevacizumab versus FOLFIRI-bevacizumab as first-line treatment in patients with metastatic colorectal cancer: a Hellenic Cooperative Oncology Group phase III trial with collateral biomarker analysis
Background The aim was to compare two standard chemotherapy regimens combined with bevacizumab as first-line treatment in patients with metastatic colorectal cancer. Methods Patients previously untreated for metastatic disease were randomized in: group A (irinotecan, capecitabine, bevacizumab, every 3 weeks; XELIRI-bevacizumab) and group B (irinotecan, leucovorin, fluorouracil, bevacizumab, every 2 weeks; FOLFIRI-bevacizumab). Primary endpoint was progression-free survival (PFS). Plasma concentrations of nitric oxide, osteopontin, TGF-β1 and VEGF-A were measured at baseline and during treatment. Results Among 285 eligible patients, 143 were randomized to group A and 142 to group B. Fifty-five patients (38.5%) in group A and 57 (40.1%) in group B responded (p = 0.81). After a median follow-up of 42 months, median PFS was 10.2 and 10.8 months (p = 0.74), while median OS was 20.0 and 25.3 months (p = 0.099), for groups A and B, respectively. Most frequent grade 3–4 toxicities (group A vs group B) were neutropenia (13% vs 22%, p = 0.053) and diarrhea (19% vs 11%, p = 0.082). Baseline plasma osteopontin concentrations demonstrated prognostic significance for both PFS and OS. Conclusions This trial did not show significant differences in efficacy between the groups. However, the toxicity profile was different. Baseline plasma osteopontin concentrations demonstrated independent prognostic significance. (Registration number: ACTRN12610000270011)
Bortezomib overcomes MGMT-related resistance of glioblastoma cell lines to temozolomide in a schedule-dependent manner
Summary Development of drug resistance after standard chemotherapy for glioblastoma multiforme (GBM) with temozolomide (TMZ) is associated with poor prognosis of GBM patients and is at least partially mediated by a direct DNA repair pathway involving O6-methylguanine methyltransferase (MGMT). This enzyme is under post-translational control by a multisubunit proteolytic cellular machinery, the 26S proteasome. Inhibition of the proteasome by bortezomib (BZ), a boronic acid dipeptide already in clinical use for the treatment of myeloma, has been demonstrated to induce growth arrest and apoptosis in GBM cells. In this study we investigated the effect of sequential treatment with BZ and TMZ on cell proliferation-viability and apoptosis of the human T98G and U87 GBM cell lines. We also tested for an effect of treatment on MGMT expression and important upstream regulators of the latter, including nuclear factor kappa B (NFκB), p44/42 mitogen-activated protein kinase (MAPK), p53, signal transducer and activator of transcription 3 (STAT3) and hypoxia-inducible factor 1α (HIF-1α). The sequence of drug administration for maximal cytotoxicity favored BZ prior to TMZ in T98G cells while the opposite was the case for U87 cells. Maximal efficacy was associated with downregulation of MGMT, reduced IκBα-mediated proteasome-dependent nuclear accumulation of NFκB, attenuation of p44/42 MAPK, AKT and STAT3 activation, and stabilization of p53 and inactive HIF-1α. Collectively, these results suggest that proteasome inhibition by BZ overcomes MGMT-mediated GBM chemoresistance, with scheduling of administration being critical for obtaining the maximal tumoricidal effect of combination with TMZ.
Nutritional status, acute phase response and depression in metastatic lung cancer patients: correlations and association prognosis
Background and aim Cancer cachexia is a metabolic syndrome related with poor outcome. Cytokines play a key role in the pathophysiology of that syndrome. The aim of this study was to investigate the potential correlations between nutritional status, systemic inflammation, and psychological distress in cancer patients. The prognostic significance of the recorded parameters was also assessed. Patients and methods Patients with metastatic lung cancer were eligible. Mini Nutritional Assessment (MNA) was used for the evaluation of nutritional status, Glasgow Prognostic Score (GPS) for the estimation of systemic inflammation, and Hospital Anxiety and Depression Scale (HADS) for psychological assessment. Results Totally, 122 patients were enrolled (71.3% with NSCLC and 28.7% with SCLC). The following correlations were observed: MNA and GPS ( r  = 0.289, p  = 0.001), MNA and HADS (depression scale) ( r  = 0.275, p  = 0.002), GPS and HADS (depression scale) ( r  = 0.256, p  = 0.004), and GPS and HADS (anxiety scale) ( r  = 0.194, p  = 0.033). In univariate analysis, GPS ( p  = 0.002) and MNA ( p  = 0.010) emerged as significant predictors of survival. In multivariate analysis, both MNA ( p  = 0.032) and GPS ( p  = 0.020) retained their importance. Conclusions This study highlights the associations between nutritional status, systemic inflammation, and psychological distress, supporting their common underlying pathophysiological mechanisms and further suggesting the necessity of a holistic anti-cachectic approach.
Infections Due to Multidrug-Resistant Bacteria in Oncological Patients: Insights from a Five-Year Epidemiological and Clinical Analysis
Bacterial infections are frequent complications in cancer patients. Among them, those caused by multidrug-resistant (MDR) bacteria increase morbidity and mortality mainly because of limited therapeutic options. Current knowledge regarding MDR infections in patients with solid tumors is limited. We assessed the epidemiology and risk factors of increased mortality in these patients. In this retrospective five-year single cohort observational study, we included all oncological patients with MDR infections. Cancer-related parameters, comorbidities, prior use of antibiotics, previous surgical interventions and hospitalization, as well as the use of invasive procedures were investigated as potential risk factors causing adverse outcomes. Seventy-three patients with MDR infection were included: 37% with carbapenem-resistant Klebsiella pneumoniae, 24% with oxacillin-resistant Staphylococcus aureus (MRSA) and 21% with carbapenem-resistant Acinetobacter baumanni. Previous colonization with MDR bacteria was detected in 14% patients, while 20% of the patients presented MDR colonization or infection at ward admission. Mortality during the infection episode was 32%. Duration of hospitalization and CRP were statistically significant risk factors of mortality, whereas administration of guided antibiotics was a protective factor. Knowledge of local epidemiology of MDR bacteria can help physicians promptly identify cancer patients at risk of MDR infections and initiate timely effective empirical antibiotic treatment that can eventually improve the overall therapeutic management.
Lapatinib with whole brain radiotherapy in patients with brain metastases from breast and non-small cell lung cancer: a phase II study of the Hellenic Cooperative Oncology Group (HeCOG)
Small molecules, mainly tyrosine kinase inhibitors, are currently used in various malignancies. Lapatinib, a dual inhibitor of EGFR/HER2 tyrosine kinases, has demonstrated effectiveness in brain metastases from HER2-overexpressing breast cancer. It also appears to sensitize EGFR-expressing cell lines to radiation. To evaluate the efficacy of lapatinib in combination with whole brain radiotherapy (WBRT) in patients with brain metastases from non-small cell lung cancer (NSCLC) and breast cancer, as assessed by volumetric analysis by MRI. 81 patients were treated with WBRT (30 Gy in ten fractions) in combination with lapatinib 1250 mg once daily, followed by lapatinib 1500 mg once daily for a total 6 weeks. 21 patients had primary breast cancer and 60 patients NSCLC. Pre- and post-treatment MRI scans in a compact disk for central volumetric assessment were available for 43 patients. 27 patients (62.8%) achieved partial response, 15 patients (34.9%) had stable disease and only one patient (2.3%) had disease progression. Response was not associated to EGFR protein expression. All 81 patients were assessed for safety. The large majority of the adverse events were mild. Eight deaths occurred, four of which were considered related to the study drugs but there were also other contributing factors. Nine cases of serious infections were observed in eight patients, but they were also receiving dexamethasone. Lapatinib in combination with WBRT in patients with brain metastases from breast cancer and NSCLC is a feasible approach that can be further studied in larger clinical trials.
Management of Cancer-associated Thrombosis (CAT): Symptomatic or Incidental
Cancer-associated thrombosis (CAT), the second leading cause of death in patients with cancer can be treated with low molecular weight heparin (LMWH) according to guidelines. A multicenter prospective observational study was carried out to record anti-thrombotic treatment practice, assess thrombosis recurrence and bleeding, and identify potential risk factors. Adult patients from 18 Oncology Departments throughout Greece were followed-up for 12 months. A total of 120 patients with CAT receiving anticoagulant treatment were enrolled (35% incidental); 85% were treated for more than 6 months, 95.8% were treated with tinzaparin and smaller percentages with other agents. Thrombosis recurred in three patients and there was minor bleeding in four patients. Bleeding was associated with high body mass index (>35 kg/m ), trauma history, renal insufficiency and bevacizumab use. Incidental thrombosis contributes significantly to CAT burden. Long-term use of LMWH seems to be effective and safe. Several risk factors associated with bleeding should be considered during anti-coagulation therapy planning.
Expression and prognostic significance of VEGF and mTOR pathway proteins in metastatic renal cell carcinoma patients: a prognostic immunohistochemical profile for kidney cancer patients
Purpose To identify prognostic molecular profiles in patients with mRCC treated with sunitinib, we performed immunohistochemical analysis for VEGF and PI3K/Akt/mTOR pathway components. Methods The immunohistochemical expression of VEGF, p85α, p110γ, PTEN, p-Akt, p-mTOR, p-4E-BP1 and p-p70S6K was studied in 79 patients with mRCC who received first-line treatment with sunitinib. Expression was correlated with clinicopathological features and survival. Results VEGF was highly expressed (median H-Score 150), while positivity for the markers of the PI3K/Akt/mTOR pathway was: p85α 43/66 (65 %), p110γ41/60 (68 %), PTEN 32/64 (50 %), p-Akt57/63 (90 %), p-mTOR48/64 (75 %), p-4E-BP1 58/64 (90 %) and p-p70S6K 60/65 (92 %). No single immunohistochemical marker was found to have prognostic significance. Instead, the combination of increased p-mTOR and low VEGF expression was adversely correlated with overall survival (OS) (3.2 vs. 16.9 months, P  = 0.001). Conclusion Immunohistochemistry for VEGF and p-mTOR proteins may discriminate patients refractory to first-line sunitinib with poor prognosis. Prospective validation of our findings is needed.
Dose-dense sequential adjuvant chemotherapy followed, as indicated, by trastuzumab for one year in patients with early breast cancer: first report at 5-year median follow-up of a Hellenic Cooperative Oncology Group randomized phase III trial
Background Dose-dense sequential chemotherapy including anthracyclines and taxanes has been established in the adjuvant setting of high-risk operable breast cancer. However, the preferable taxane and optimal schedule of administration in a dose-dense regimen have not been defined yet. Methods From July 2005 to November 2008, 1001 patients (990 eligible) were randomized to receive, every 2 weeks, 3 cycles of epirubicin 110 mg/m 2 followed by 3 cycles of paclitaxel 200 mg/m 2 followed by 3 cycles of intensified CMF (Arm A; 333 patients), or 3 cycles of epirubicin followed by 3 cycles of CMF, as in Arm A, followed 3 weeks later by 9 weekly cycles of docetaxel 35 mg/m 2 (Arm B; 331), or 9 weekly cycles of paclitaxel 80 mg/m 2 (Arm C; 326). Trastuzumab was administered for one year to HER2-positive patients post-radiation. Results At a median follow-up of 60.5 months, the 3-year disease-free survival (DFS) rate was 86%, 90% and 88%, for Arms A, B and C, respectively, while the 3-year overall survival (OS) rate was 96% in all arms. No differences were found in DFS or OS between the combined B and C Arms versus Arm A (DFS: HR = 0.81, 95% CI: 0.59-1.11, P  = 0.20; OS: HR = 0.84, 95% CI: 0.55-1.30, P  = 0.43). Among the 255 patients who received trastuzumab, 189 patients (74%) completed 1 year of treatment uneventfully. In all arms, the most frequently reported severe adverse events were neutropenia (30% vs. 27% vs. 26%) and leucopenia (12% vs. 13% vs. 12%), while febrile neutropenia occurred in fifty-one patients (6% vs. 4% vs. 5%). Patients in Arm A experienced more often severe pain ( P  = 0.002), neurological complications ( P  = 0.004) and allergic reactions ( P  = 0.004), while patients in Arm B suffered more often from severe skin reactions ( P  = 0.020). Conclusions No significant differences in survival between the regimens were found in the present phase III trial. Taxane scheduling influenced the type of severe toxicities. HER2-positive patients demonstrated comparable 3-year DFS and OS rates with those reported in other similar studies. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000151033 .