Treatment with Imatinib in NSCLC is associated with decrease of phosphorylated PDGFR-beta and VEGF expression, decrease in interstitial fluid pressure and improvement of oxygenation

Elevated intratumoral interstitial fluid pressure (IFP) and tumour hypoxia are independent predictive factors for poor survival and poor treatment response in cancer patients. However, the relationship between IFP and tumour hypoxia has not yet been clearly established. Preclinical studies have shown that lowering IFP improves treatment response to cytotoxic therapy. Interstitial fluid pressure can be reduced by inhibition of phosphorylated platelet-derived growth factor receptor-beta (p-PDGFR-beta), a tyrosine kinase receptor frequently overexpressed in cancer stroma, and/or by inhibition of VEGF, a growth factor commonly overexpressed in tumours overexpressing p-PDGFR-beta. We hypothesised that Imatinib, a specific PDGFR-beta inhibitor will, in addition to p-PDGFR-beta inhibition, downregulate VEGF, decrease IFP and improve tumour oxygenation. A549 human lung adenocarcinoma xenografts overexpressing PDGFR-beta were grown in nude mice. Tumour-bearing animals were randomised to control and treatment groups (Imatinib 50 mg kg(-1) via gavage for 4 days). Interstitial fluid pressure was measured in both groups before and after treatment. EF5, a hypoxia marker, was administered 3 h before being killed. Tumours were sectioned and stained for p-PDGFR-beta, VEGF and EF5 binding. Stained sections were viewed with a fluorescence microscope and image analysis was performed. Imatinib treatment resulted in significant reduction of p-PDGFR-beta, VEGF and IFP. Tumour oxygenation was also significantly improved. This study shows that p-PDGFR-beta-overexpressing tumours can be effectively treated with Imatinib to decrease tumour IFP. Importantly, this is the first study demonstrating that Imatinib treatment improves tumour oxygenation and downregulates tumour VEGF expression.     

Prognostic Significance of Carbonic Anhydrase IX (CA-IX), Endoglin (CD105) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in Breast Cancer Patients

The aim of this study was to examine the prognostic significance of carbonic anhydrase IX (CA-IX), an endogenous marker for tumor hypoxia; endoglin (CD105), a proliferation-associated and hypoxia-inducible glycoprotein and 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidative DNA lesion, in breast cancer patients. Immunohistochemical expressions of CA-IX, CD105 and 8-OHdG, analyzed on paraffin-embedded tumor tissues from forty female breast cancer patients, were used to assess their prognostic implication on overall survival (OS) and relapse-free survival (RFS). Patients with high CA-IX expression (above cut-off value) had a higher occurrence of relapse (P = 0.002). High CA-IX expression was significantly associated with shorter RFS (P < 0.001, hazard ratio (HR) 0.21) and shorter OS (P < 0.001, HR 0.19). Lymph node negative patients with high CA-IX expression had worse RFS (P = 0.031, HR 0.14) and OS (P = 0.005, HR 0.05). Patients with grade I&II tumors and high CA-IX expression showed shorter RFS (P = 0.028, HR 0.28) and OS (P = 0.008, HR 0.20). Worse OS (P = 0.046, HR 0.28) was found in subgroup of patients with grade II tumors and high CA-IX expression. Among all three markers, only high CA-IX expression was strong independent prognostic indicator for shorter OS (HR 4.14, 95% CI 1.28–13.35, P = 0.018) and shorter RFS (HR 3.99, 95% CI 1.38–11.59, P = 0.011). Elevated expression of CA-IX was an independent prognostic factor for decreased RFS and OS and a significant marker for tumor aggressiveness. CD105 had week prognostic value; whereas, 8-OHdG, in this study, did not provide sufficient evidence as a prognostic indicator in breast cancer patients.     

Prostate secretory protein PSP-94 decreases tumor growth and hypercalcemia of malignancy in a syngenic in vivo model of prostate cancer

Prostate cancer is a common malignancy affecting men, which is often associated with skeletal metastases resulting in significant morbidity and mortality. In this hormone-dependent cancer, low levels of a prostate secretory protein of 94 amino acids (PSP-94) are associated with advanced disease stage. In the current study, we have examined the effect of PSP-94 on prostate cancer growth and experimental metastases to the skeleton. For these studies, MatLyLu rat prostate cancer cells were transfected with full-length cDNA encoding parathyroid hormone-related protein [PTHrP (MatLyLu-PTHrP cells)], which is known to be the major pathogenetic factor for malignancy-associated hypercalcemia. MatLyLu-PTHrP cells were inoculated s.c. into the right flank or via intracardiac route into the left ventricle of syngeneic male Copenhagen rats. Intracardiac inoculation of MatLyLu cells routinely results in the development of tumors in the lumbar vertebrae, resulting in hind-limb paralysis. Animals were infused with different doses of PSP-94 (0.1, 1.0, and 10.0 micro g/kg/day) starting on the day of tumor cell inoculation. Time of hind-limb paralysis and tumor volume were determined, and comparison was made between PSP-94-treated animals and control animals receiving vehicle alone. At the end of the study, animals were sacrificed, and plasma calcium, plasma PTHrP, and tumor PTHrP levels were determined. Whereas the highest dose of PSP-94 caused a modest but statistically significant delay in the development of hind-limb paralysis, a marked dose-dependent decrease in primary tumor volume was seen in experimental animals receiving PSP-94 due to its ability to promote tumor cell apoptosis. Furthermore, whereas control animals routinely developed hypercalcemia due to PTHrP production, treatment with PSP-94 led to a near normalization of plasma calcium and a marked reduction in PTHrP production as determined by radioimmunoassay and immunohistochemistry. Collectively, these results demonstrate the ability of PSP-94 to be an effective treatment modality for prostate cancer, where decrease in plasma PTHrP and calcium levels can serve as useful biochemical markers for monitoring the efficacy of this novel antitumor agent.     

The role of hyperthermia in regional alkylating agent chemotherapy.

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 micrograms/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 micrograms/mL. However, administration of high-dose l-phenylalanine mustard, 50 micrograms/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.     

Chemical composition of the essential oil from kelussia odoratissima Mozaff. and the evaluation of its sedative and anxiolytic effects in mice

OBJECTIVE:

The present study aimed to evaluate the sedative and anxiolytic effects of the essential oils and hydroalcoholic extract of Kelussia odoratissima Mozaff. (K. odoratissima) in mice by utilizing an elevated plus maze. The chemical composition of its essential oil was also determined.

METHODS:

The hydroalcoholic extract or essential oil fraction from this plant were administered intraperitoneally to male mice at various doses 30 min before testing. The anxiolytic and sedative effects were determined by an elevated plus maze and locomotor activity tests, respectively.

RESULTS:

According to the results, none of the administered doses of hydroalcoholic extract or essential oil fraction of K. odoratissima changed the percentage of the time spent or number of entries into the open arms of the elevated plus maze. In contrast, the cumulative spontaneous locomotor activity of mice treated with the essential oil or hydroalcoholic extract was significantly decreased. Chemical analysis of the essential oil by Gas chromatography-mass spectromentry (GC-MS) showed that 3-butylidene-4,5-dihydrophthalide (85.9%) was the major component.

CONCLUSION:

These data confirm the sedative properties of K. odoratissima, yet there were no profound anxiolytic effects observed.     

Increased Glycation and Oxidative Damage to Apolipoprotein B100 of LDL Cholesterol in Patients With Type 2 Diabetes and Effect of Metformin

OBJECTIVE

The aim of this study was to investigate whether apolipoprotein B100 of LDL suffers increased damage by glycation, oxidation, and nitration in patients with type 2 diabetes, including patients receiving metformin therapy.

RESEARCH DESIGN AND METHODS

For this study, 32 type 2 diabetic patients and 21 healthy control subjects were recruited; 13 diabetic patients were receiving metformin therapy (median dose: 1.50 g/day). LDL was isolated from venous plasma by ultracentrifugation, delipidated, digested, and analyzed for protein glycation, oxidation, and nitration adducts by stable isotopic dilution analysis tandem mass spectrometry.

RESULTS

Advanced glycation end product (AGE) content of apolipoprotein B100 of LDL from type 2 diabetic patients was higher than from healthy subjects: arginine-derived AGE, 15.8 vs. 5.3 mol% (P < 0.001); and lysine-derived AGE, 2.5 vs. 1.5 mol% (P < 0.05). Oxidative damage, mainly methionine sulfoxide residues, was also increased: 2.5 vs. 1.1 molar equivalents (P < 0.001). 3-Nitrotyrosine content was decreased: 0.04 vs. 0.12 mol% (P < 0.05). In diabetic patients receiving metformin therapy, arginine-derived AGE and methionine sulfoxide were lower than in patients not receiving metformin: 19.3 vs. 8.9 mol% (P < 0.01) and 2.9 vs. 1.9 mol% (P < 0.05), respectively; 3-nitrotyrosine content was higher: 0.10 vs. 0.03 mol% (P < 0.05). Fructosyl-lysine residue content correlated positively with fasting plasma glucose. Arginine-derived AGE residue contents were intercorrelated and also correlated positively with methionine sulfoxide.

CONCLUSIONS

Patients with type 2 diabetes had increased arginine-derived AGEs and oxidative damage in apolipoprotein B100 of LDL. This was lower in patients receiving metformin therapy, which may contribute to decreased oxidative damage, atherogenicity, and cardiovascular disease.Cardiovascular disease (CVD) is the major cause of premature death in diabetes. Type 2 diabetes is associated with a twofold to threefold increased risk of coronary heart disease in men and a threefold to fivefold increased risk in women, relative to the nondiabetic population (1). Dyslipidemia is a key feature of diabetic CVD where small dense LDL particles pose a major atherogenic threat. The underlying mechanism producing small, dense LDL is related to hepatic oversecretion of apolipoprotein B100 (apoB100) and impaired clearance of LDL by the high-affinity LDL receptor in which both hepatic and peripheral tissues participate (2). The normal residence time of LDL in plasma is 3 days but this is increased to 5 days for small, dense, highly atherogenic LDL (3). Atherogenicity and plasma residence time of LDL may be influenced by damage to apoB100 by glycation, oxidation, and nitration but the quantitative amounts of damage in healthy human subjects and diabetic patients remain unclear.Glycation of proteins is a complex series of parallel and sequential reactions collectively called the Maillard reaction. Early stage reactions are directed to lysine and NH₂-terminal amino acid residues leading to the formation of the early glycation adduct, fructosyl-lysine (FL), and other fructosamine derivatives. Later stage reactions form advanced glycation end products (AGEs). FL degrades slowly to form AGEs. Glyoxal, methylglyoxal, and 3-deoxyglucosone (3-DG) are physiological dicarbonyl metabolites and potent glycating agents formed by the degradation of glycolytic intermediates, glycated proteins, and lipid peroxidation. They react with proteins to form AGEs directed mainly to arginine residues—often functionally important arginine residues. The most important AGEs quantitatively are hydroimidazolones derived from arginine residues modified by glyoxal, methylglyoxal, and 3-DG: G-H1, MG-H1, and 3DG-H, respectively. N_ω-carboxymethyl-arginine (CMA) is a further arginine-derived adduct formed by glyoxal. Other important and widely studied AGEs are N_ε-carboxymethyl-lysine (CML), N_ε-carboxyethyl-lysine (CEL), and pentosidine. Markers of oxidative damage to proteins are methionine sulfoxide (MetSO), formed by the oxidation of methionine, and dityrosine, formed by oxidative cross-linking of tyrosine. A widely studied marker of nitration damage to proteins is 3-nitrotyrosine (3-NT) (rev. in 4) (Fig. 1).Open in a separate windowFIG. 1.Molecular structures of protein glycation, oxidation, and nitration residues.Metformin is the most widely prescribed oral glucose-lowering agent for the treatment of type 2 diabetes. It improves glycemic control and decreases the risk of CVD (5). Metformin therapy of type 2 diabetic patients increased LDL particle size (6) and decreased plasma concentrations of remnant lipoprotein cholesterol, a predictor of myocardial infarction and thought to reflect increased residence time and atherogenicity of cholesterol ester–rich chylomicrons and VLDL (7). Metformin also decreased the plasma concentrations of methylglyoxal in diabetic patients (8) and may decrease oxidative stress and related oxidation of LDL (9).In this study, we used the gold standard method of stable isotopic dilution analysis liquid chromatography–tandem mass spectrometry (LC-MS/MS) to measure protein glycation, oxidation, and nitration adducts in apoB100 of LDL to assess whether there is increased lipoprotein damage in patients with type 2 diabetes with respect to normal healthy control subjects and to investigate the effect of metformin therapy.