Ilaria Portarena

Poly(ADP-ribose) polymerase inhibitor increases growth inhibition and reduces G2/M cell accumulation induced by temozolomide in malignant glioma cells

Temozolomide (TZM) is a novel methylating agent currently under investigation for treatment of recurrent high‐grade gliomas. Although TZM generates a wide spectrum of methyl adducts, its cytotoxicity has been attributed to mismatch repair (MR)‐mediated processing of O6‐methylguanine:T mispairs. N3‐methyladenine and N7‐methylguanine adducts are promptly repaired by the base excision repair system, unless a poly(ADP‐ribose) polymerase (PARP) inhibitor is combined to TZM. In this case, the repair process of N‐methylpurines cannot be completed and the deriving DNA strand breaks contribute to cytotoxicity. In this study, we investigated the influence on cell growth and cell cycle of treatment with TZM + PARP inhibitor in glioma cells characterized by different susceptibility to TZM. The results indicated that PARP inhibitor increases growth inhibition induced by TZM in either p53–wild‐type or p53‐mutant glioblastoma cells, as early as 24 h after drug exposure. The enhancing effect exerted by PARP inhibitor was particularly evident in glioma cells characterized by a defective expression of MR, since these cells are tolerant to O6‐methylguanine damage and show low sensitivity to TZM. In O6‐alkylguanine‐DNA alkyltransferase (OGAT)‐deficient and MR‐proficient tumor cells bearing wild‐type p53, the drug combination markedly reduced cell accumulation in the G2/M phase of cell cycle and induction of the G2 checkpoint regulator Chk1 kinase. In short‐term cultures of glioma cells derived from surgical specimens, PARP inhibitor enhanced chemosensitivity to TZM and this effect was especially evident in OGAT‐proficient tumors. Thus, a pharmacological strategy based on the interruption of N‐methylpurine repair might represent a novel strategy to restore or increase glioma sensitivity to TZM. GLIA 40:44–54, 2002.

Poly (ADP-ribose) polymerase inhibitor increases apoptosis and reduces necrosis induced by a DNA minor groove binding methyl sulfonate ester.

The poly(ADP-ribose) polymerase (PARP) is involved in cell recovery from DNA damage, such as methylation of N3-adenine, that activates the base excision repair process. In the present study we demonstrated that MeOSO2(CH2)2-lexitropsin (Me-Lex), a methylating agent that almost exclusively produces N3-methyladenine, induced different modalities of cell death in human leukemic cell lines, depending on the presence of PARP inhibitor. Growth inhibition, provoked by the combination of Me-Lex and PARP inhibitor, was associated with a marked down-regulation of c-myc, increased generation of single strand breaks and apoptosis. When used as single agent, at concentrations that saturated cell repair ability, Me-Lex induced mainly cell death by necrosis. Surprisingly, addition of a PARP inhibitor enhanced apoptosis and reduced the early appearance of necrosis. Telomerase activity was completely suppressed in cells exposed to Me-Lex alone, by 24 h after treatment, whereas it did not change when Me-Lex was combined with PARP inhibitor. Thereafter, inhibition of telomerase was observed with both treatments. The results suggest new insights on different modalities of cell death induced by high levels of N3-methyladenine per se, or by the methylated base in the presence of PARP inhibitor. Cell Death and Differentiation (2001) 8, 817–828

Combined effects of adenovirus-mediated wild-type p53 transduction, temozolomide and poly (ADP-ribose) polymerase inhibitor in mismatch repair deficient and non-proliferating tumor cells

Lack of p53 or mismatch repair (MR) function and scarce cell proliferation are commonly associated with tumor cell resistance to antineoplastic agents. Recently, inhibition of poly(ADP-ribose) polymerase (PARP) has been considered as a tool to overcome resistance of MR-deficient tumors to methylating agents. In the present study we demonstrated that infection with p53 expressing adenovirus (Ad-p53), enhances chemosensitivity of MR-deficient tumor cell lines to the methylating agent temozolomide (TZM), either used as single agent or, more efficiently, when combined with PARP inhibitor. Moreover, the association of Ad-p53 with drug treatment induced a more pronounced growth inhibitory effect than that provoked by Ad-p53 infection only. Cells, growth arrested by p53 transduction, and then subsequently exposed to the drugs, were still highly susceptible to cytotoxicity induced by TZM and PARP inhibitor. The results suggested that this drug combination might be effective even in non-proliferating tumor cells. It is conceivable to envisage future possible strategies to enhance cytostatic or cytotoxic effects induced by Ad-p53, based on the use of TZM, alone or combined with PARP inhibitor for the therapy of resistant tumors. Cell Death and Differentiation (2001) 8, 457–469

Novel High-Sensitive D-Dimer Determination Predicts Chemotherapy-Associated Venous Thromboembolism in Intermediate Risk Lung Cancer Patients

INTRODUCTION We hypothesized that the use of a novel high sensitivity (HS) assay for D-dimer determination might ameliorate venous thromboembolism (VTE) risk prediction in intermediate risk lung cancer patients in whom chemotherapy could act as a trigger for VTE onset. PATIENTS AND METHODS Pretreatment HS D-dimer levels were retrospectively evaluated in 108 lung cancer outpatients using a novel automated latex enhanced turbidimetric immunoassay. All patients were at the start of a new platinum-based chemotherapy regimen and were classified as intermediate risk according to Khoranas assessment model. Patients were followed-up for a median period of 6.9 months. RESULTS Receiver operating characteristic (ROC) curves and corresponding Bayesian analysis showed that the best performance was obtained at a cutoff level of 1500 ng/mL, which resulted in a sensitivity of 81%, a specificity of 69%, a positive predictive value (PPV) of 31%, a negative predictive value (NPV) of 96%, and an accuracy of 70%. Patients with HS D-dimer levels above the cutoff had a worse VTE-free survival (60%) compared with those with levels below the cutoff (95%; P = .0001). Multivariate Cox proportional hazards survival analysis confirmed that pretreatment HS D-dimer levels were able to significantly predict VTE with a hazard ratio of 11 (95% confidence interval, 2.62-46.2; P = .001), independently of classic VTE risk factors. CONCLUSIONS The use of HS D-dimer determination prior to chemotherapy might allow for VTE risk stratification of intermediate risk cancer patients, helping in identifying those individuals who could benefit from thromboprophylaxis.

Cytotoxic and clastogenic effects of a DNA minor groove binding methyl sulfonate ester in mismatch repair deficient leukemic cells

Mismatch repair deficiency contributes to tumor cell resistance to O6-guanine methylating compounds and to other antineoplastic agents. Here we demonstrate that MeOSO2(CH2)2- lexitropsin (Me-Lex), a DNA minor groove alkylating compound which generates mainly N3-methyladenine, has cytotoxic and clastogenic effects in mismatch repair-deficient leukemic cells. Moreover, MT-1 cells, which express p53 upon drug treatment and possess low levels of 3-methylpurine DNA glycosylase activity, are more susceptible to cytotoxicity induced by Me-Lex, with respect to p53-null and 3-methylpurine DNA glycosylase-proficient Jurkat cells. In both cell lines, the poly(ADP-ribose) polymerase inhibitor 3-aminobenzamide, which inhibits base excision repair capable of removing N-methylpurines, increases cytotoxicity and clastogenicity induced by Me-Lex or by temozolomide, which generates low levels of N3-methyl adducts. The enhancing effect is more evident at low Me-Lex concentrations, which induce a level of DNA damage that presumably does not saturate the repair ability of the cells. Nuclear fragmentation induced by Me-Lex + 3-aminobenzamide occurs earlier than in cells treated with the single agent. Treatment with Me-Lex and 3-aminobenzamide results in augmented expression of p53 protein and of the X-ray repair cross- complementing 1 transcript (a component of base excision repair). These results indicate that N3-methyladenine inducing agents, alone or combined with poly(ADP-ribose) polymerase inhibitors, could open up novel chemotherapeutic strategies to overcome drug resistance in mismatch repair-deficient leukemic cells.

Role of CA19.9 in predicting bevacizumab efficacy for metastatic colorectal cancer patients

CEA and CA19.9 are biomarkers routinely measured for monitoring treatment response in metastatic colorectal cancer (MCRC) patients, yet their predictive value during therapies containing new antineoplastic drugs (i.e. FOLFIRI/OLFOX/Bevacizumab) has not yet been investigated. Consecutive chemotherapy-naive MCRC patients treated with either standard chemotherapy-alone (FOLFIRI/FOLFOX) or chemotherapy+bevacizumab (FOLFIRI+bevacizumab) were included in the analysis. Patients had to have serial biweekly measurement of CEA and CA19.9 available for at least three months of treatment. Primary study endpoint was Progression Free Survival (PFS). Biomarker levels and type of treatment as well as major demographic and clinical factors were analyzed for their impact on PFS. Out of 243 evaluated MCRC patients, 87 had biomarkers available as per inclusion criteria. Among all evaluated factors only type of treatment (chemotherapy-alone vs chemotherapy+bevacizumab) and baseline CA19.9 (> vs < normal) were independently associated with PFS, whilst neither baseline CEA nor biomarker reduction during therapy reached statistical significance. When patients with different baseline CA19.9 levels were analysed separately, only patients with abnormal CA19.9 benefited significantly from the administration of bevacizumab.The current study demonstrated a significant predictive value of CA19.9, but not of CEA and biomarker reduction, for MCRC patients treated with new antineoplastic drugs. Moreover, only patients with abnormal baseline CA19.9 levels benefited significantly from bevacizumab.

Prognostic Value of Carcinoembryonic Antigen and Vascular Endothelial Growth Factor Tumor Tissue Content in Colorectal Cancer

Aim: This study was designed to assess the prognostic significance of the combined measurement of vascular endothelial growth factor (VEGF) and carcinoembryonic antigen (CEA) tissue content with respect to relapse-free and overall survival of patients with colorectal cancer (CRC). Methods: Quantitative evaluation of VEGF and CEA content was performed on protein extracts obtained from tissue biopsies from 69 CRC patients and 15 healthy donors. Results: VEGF significantly correlated with CEA content of either tumor tissues (rho = 0.55, p < 0.0001) or corresponding normal mucosa (rho = 0.34, p < 0.005). General regression analyses demonstrated that CEA was an independent predictor of VEGF tissue content either in CRC biopsies (regression coefficient = 0.57, p < 0.0001) or normal mucosa (regression coefficient = 0.25, p < 0.05). Cox proportional hazards survival analysis showed that tumor tissue content of both VEGF and CEA had an independent prognostic value in predicting both relapse-free (hazards ratio = 5.98, p = 0.002) and overall (hazards ratio = 4.73, p = 0.007) survival, irrespective of Dukes’ stage. Kaplan-Meier analysis demonstrated that an elevated tumor content of both CEA and VEGF had a negative prognostic value in respect to either relapse-free (log-rank test: 10.4, p = 0.001) or overall survival (log-rank test: 7.33, p = 0.007). Conclusion: Tumor tissue VEGF and CEA content determination might add useful prognostic information in the management of patients with CRC.

An activated protein C-dependent thrombin generation assay predicts chemotherapy-associated venous thromboembolism in cancer patients.

An activated protein C-dependent thrombin generation assay predicts chemotherapy-associated venous thromboembolism in cancer patients -

Serum sE-Selectin Levels and Carcinoembryonic Antigen mRNA-Expressing Cells in Peripheral Blood as Prognostic Factors in Colorectal Cancer Patients

This study analyzed the possible prognostic value of presurgical serum soluble (s)E‐selectin levels and/or carcinoembryonic antigen (CEA) mRNA positivity in predicting the disease‐free survival of colorectal cancer (CRC) patients.

Evaluation of mean platelet volume as a predictive marker for cancer-associated venous thromboembolism during chemotherapy

Mean platelet volume has been proposed as a predictor for venous thromboembolism in cancer. We, therefore, investigated the effects of different anti-cancer drugs on mean platelet volume in order to assess its possible value in the risk prediction of a first thromboembolic episode in cancer outpatients during treatment. Pre-treatment mean platelet volumes were retrospectively evaluated in 589 ambulatory patients at the beginning of a new chemotherapy regimen. Moreover, serial changes were evaluated at baseline and before each chemotherapy cycle on 385 of the 589 patients who consented to have additional blood withdrawals during treatment. Cox proportional hazards survival analysis demonstrated a 2.7 hazard ratio (P=0.01) of developing a first venous thromboembolic episode during chemotherapy for patients with baseline mean platelet volumes below the 10th percentile (<7.3 fL). This index significantly declined during the first three months of chemotherapy (−6%; P<0.0001) reverting to baseline at the end of treatment. Multivariate regression analysis showed that normal baseline volumes (P=0.012) and platinum-based regimens (P=0.017) were both independent predictors of mean platelet volume decline during chemotherapy which, in turn, was associated with a 2.4 hazard ratio (P=0.044) of venous thromboembolism. In conclusion, low pre-chemotherapy mean platelet volume might be regarded as a predictor of increased venous thromboembolism risk in cancer patients and chemotherapy further decreases platelet volumes, possibly due to drug-induced platelet activation and destruction. Changes in mean platelet volumes during chemotherapy might provide additional information on thromboembolic risk of patients treated with anti-cancer drugs, particularly platinum compounds.