Targeting Mcl-1 for the therapy of cancer

INTRODUCTION: Human cancers are genetically and epigenetically heterogeneous and have the capacity to commandeer a variety of cellular processes to aid in their survival, growth and resistance to therapy. One strategy is to overexpress proteins that suppress apoptosis, such as the Bcl-2 family protein Mcl-1. The Mcl-1 protein plays a pivotal role in protecting cells from apoptosis and is overexpressed in a variety of human cancers. AREAS COVERED: Targeting Mcl-1 for extinction in these cancers, using genetic and pharmacological approaches, represents a potentially effectual means of developing new efficacious cancer therapeutics. Here we review the multiple strategies that have been employed in targeting this fundamental protein, as well as the significant potential these targeting agents provide in not only suppressing cancer growth, but also in reversing resistance to conventional cancer treatments. EXPERT OPINION: We discuss the potential issues that arise in targeting Mcl-1 and other Bcl-2 anti-apoptotic proteins, as well problems with acquired resistance. The application of combinatorial approaches that involve inhibiting Mcl-1 and manipulation of additional signaling pathways to enhance therapeutic outcomes is also highlighted. The ability to specifically inhibit key genetic/epigenetic elements and biochemical pathways that maintain the tumor state represent a viable approach for developing rationally based, effective cancer therapies.     

Synthesis of some substituted furan-2(5H)-ones and derived quinoxalinones as potential anti-microbial and anti-cancer agents

In search for novel anti-cancer and anti-microbial agents with promising pharmacotoxicological profile, the synthesis of some substituted 4-halofuran-2(5H)-ones (8a–l, 9, 11) and derived halogenated quinoxalin-2(1H)-ones (12a–d) is described. Some of the halogenated furanones were readily oxidized to the corresponding 2-bromo-2-propenoic acids (13a–c) with hydrogen peroxide in alkaline medium. Twenty-two compounds were preliminary tested for their in vitro activity against three bacteria and one fungus and revealed encouraging activity. On the other hand, three compounds were screened as anti-cancer agents using cell line panel protocol and 22 compounds were subjected to cycline-dependent kinases (CDKs) inhibition screening program but were inactive.     

Dietary intake of protein is positively associated with percent body fat in middle-aged and older adults

Data on associations between dietary intake of macronutrients and body composition in the general population are sparse. This population-based, cross-sectional study of 4478 middle-aged (47-49 y) and elderly (71-74 y) men and women from the Hordaland Health Study in western Norway was conducted using a validated FFQ and measurements by dual-energy X-ray absorptiometry. The relation between macronutrient intake [percentage of total energy intake (E%)] and percent body fat was investigated in the total population and in a subgroup with intermediate BMI and stable weight (BMI within the 25th-75th percentile and weight change <5% during the last 6 y; n = 975). In the total population, protein intake (E%) was associated with higher percent body fat (partial r = 0.11; P < 0.001) in multivariate linear regression analysis. In the subgroup with intermediate BMI and stable weight, there was no association between protein intake (E%) and percent body fat. Fat intake (E%) was positively associated (partial r = 0.07) whereas carbohydrate intake (E%) was inversely associated (partial r = -0.07) with percent body fat (P = 0.042 for both) in the subgroup with intermediate BMI and stable weight. Both in the total population and in the stable weight group, physical activity was inversely related to adiposity (partial r = -0.15 and -0.12, respectively; P < 0.001). Our results may explain some of the conflicting data on the effects of macronutrients in different populations and suggest the potential importance of protein intake as a factor in obesity.     

Effect of bariatric surgery on sulphur amino acids and glutamate

Plasma total cysteine (tCys) concentrations are associated with BMI. To study the relationship between tCys and BMI, we monitored the changes in serum concentrations of tCys and metabolically related compounds in sixty obese patients (BMI 50-60 kg/m(2)) from before to 1 year after either gastric bypass surgery (mean 30 % weight loss) or duodenal switch surgery (mean 41 % weight loss). A total of fifty-eight healthy persons (BMI 17-31 kg/m(2)) served as controls. Before surgery, obese patients had modestly (approximately 17 %) higher mean serum tCys, and markedly (>2-fold) higher glutamate concentrations, than controls (P ≤ 0·001 for both). Serial examinations after surgery revealed that gastric bypass patients had no change in tCys concentrations (P = 0·22), while duodenal switch patients showed a modest (approximately 12 %) but significant decrease in tCys (P < 0·001). Total homocysteine concentrations increased in duodenal switch patients but not in gastric bypass patients. Independent of surgery type, serum concentrations of methionine and cystathionine decreased (P < 0·05 for both), while serum glutathione and taurine remained stable. Glutamate concentrations declined, as did γ-glutamyltransferase activity (P < 0·001 for both). These results show that despite 30 % weight loss, and decreases in methionine, cystathionine and glutamate, there was no significant change in serum tCys in patients after gastric bypass surgery. The decrease in tCys in patients undergoing duodenal switch could be related to malabsorption. The present findings do not suggest that BMI is a causal determinant of plasma tCys.     

Epidural Steroid and Clonidine for Chronic Intractable Post‐thoracotomy Pain: A Pilot Study

Background: Chronic post‐thoracotomy pain is relatively common after major thoracic surgery. The primary results of a pilot study using thoracic epidural steroid and clonidine injection to treat chronic intractable post‐thoracotomy pain are presented. Methods: Twenty‐one patients with intractable post‐thoracotomy pain participated in the study. Thirteen patients received thoracic epidural injection of a mixture of 150 μg clonidine and 80 mg of methylprednisolone acetate diluted in 8 mL 0.5% lidocaine. Eight patients continued with comprehensive medical management and served as a control group. A visual analog scale (VAS) for pain was recorded before treatment, 30 minutes after the epidural injection and before discharge, at 3 weeks and 6 months. Pain, sleep disturbances, appetite changes and daily activity, as well as the incidence of complications were recorded. The need for opioid rescue medications was recorded. Results: Twelve of 13 patients in the injection group reported improvement (> 50% reduction of pain) at 3 weeks and 6 months following the injection. Allodynia improved in all injection group patients compared to four of eight in the control group. Sleep disturbance, appetite changes and daily activity were improved in the injection group. The number of patients requiring opioid rescue medications was reduced from 61.5% to 15.3% during the 6‐month duration of study. Injection caused transient hypotension in 46.2% of patients. Mild sedation was noted in 30.7% of patients receiving injection; 15.3% of the patients had localized back pain at the site of injection. Discussion: Our preliminary data suggest possible efficacy of thoracic epidural steroid and clonidine mixture in the treatment of chronic post‐thoracotomy pain. No serious adverse effects were noted in this pilot study. ?     

Synthesis and antitumor evaluation of some novel pyrrolizine derivatives

Novel series of pyrrolizines (7, 9a–d, 10a–d, 11a, b, 14a–d, 16, 19, 20a, b, 24, 25a, b), pyrimido[5,4-a]pyrrolizines (12a, b, 13, 15a, b, 18, 21a, b, 22, 23a–d) and pyrido[3,2-a]pyrrolizines (17, 26a, b) were synthesized through different reactions. The chemical structures of all the synthesized pyrrolizine derivatives were determined by spectral and elemental analyses. Antitumor activity evaluation of all the prepared compounds was carried out using NR assay method against breast cancer cell line (MCF-7). The novel pyrrolizine scaffold 7 and all its prepared derivatives showed high antitumor activity comparable to that of doxorubicin.     

A novel assay for detection of hepatitis C virus-specific effector CD4(+) T cells via co-expression of CD25 and CD134

Hepatitis C virus (HCV)-specific CD4(+) effector T cell responses are likely to play a key role in the immunopathogenesis of HCV infection by promoting viral clearance and maintaining control of viraemia. As the precursor frequency of HCV-specific CD4(+) T cells in peripheral blood is low, favoured assay systems such as intracellular cytokine (ICC) or tetramer staining have limited utility for ex vivo analyses. Accordingly, the traditional lymphocyte proliferation assay (LPA) remains the gold standard, despite detecting responses in only a minority of infected subjects. Recently, we reported development and validation of a novel whole blood CD4(+) effector T cell assay based on ex vivo antigen stimulation followed by co-expression of CD25 and CD134 on CD4(+) T cells. Here we report adaptation of this assay to assessment of HCV-specific responses in cryopreserved peripheral blood mononuclear cells using standardised antigens, including peptide pools, viral supernatants and recombinant viral proteins. The assay allowed detection of HCV-specific CD4 responses in donors with both resolved and chronic infection. Responses were highly correlated with those revealed by LPA. Application of this assay will further define the role of CD4(+) T cells in the immunopathogenesis of HCV infection.     

Hypericum perforatum protects against hepatic injury induced by carbon tetrachloride

Extracts of Hypericum perforatum (St. John’s wort) have gained much interest for their antidepressant effects. The aim of the present study was to investigate the effect H. perforatum on the development of liver injury induced by treatment with carbon tetrachloride (CCl₄) in rats. Liver damage was induced by administration of carbon tetrachloride (2.8?ml/kg in olive oil). H. perforatum (25, 50, and 100?mg/kg) alone or combined with silymarin (25?mg/kg) was given once daily orally simultaneously with CCl₄ and for 14?days thereafter. Liver damage was assessed by determining serum enzyme activities and hepatic histopathology. In CCl₄-treated rats given H. perforatum at 25?mg/kg per day for 2?weeks, the elevations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in serum were significantly less than in the CCl₄ control group. Serum ALT level decreased by 14.4% and AST level by 16.6% of their corresponding control value, respectively. Serum alkaline phosphatase (ALP) level was not significantly reduced by H. perforatum at 25?mg/kg. The addition of silymarin at the dose of 25?mg/kg to H. perforatum resulted in further decrease in liver enzymes compared with H. perforatum treatment alone. Serum ALT decreased by 40.2%, AST by 37.9%, and ALP by 38.1% of the control value, respectively, after combining H. perforatum at 25?mg/kg and silymarin. On the other hand, treatment with H. perforatum at 50 or 100?mg/kg reduced serum ALT levels by 37.9–52.6%, AST levels by 30.2–53.2%, and ALP by 48.5–51.5%, respectively. Silymarin given in combination with the above doses of H. perforatum reduced serum ALT by 58.7–63.3%, AST by 56.6–60.9%, and ALP levels by 54.7–58.8%, respectively. Meanwhile, silymarin alone decreased serum ALT by 56.8%, AST by 62.6%, and ALP levels by 55.1%, respectively. The administration of CCl₄ resulted in marked increase in nitric oxide level in serum (the concentrations of nitrite/nitrate) as compared to the normal group. Treatment with H. perforatum resulted in a dose-dependent decrease in serum nitric oxide level compared with the CCl₄ control group. Blood levels of reduced glutathione were markedly decreased in CCl₄-treated rats. Reduced glutathione levels were increased significantly by 100?mg/kg H. perforatum and restored to near normal values by silymarin treatment. Histopathological examination also indicated that CCl₄-induced liver injury was less severe in the H. perforatum-treated groups. Taken together, the present results show that H. perforatum reduces the extent of hepatic injury caused by CCl₄ in rats and this effect is increased by co-administration of silymarin. This suggests the beneficial effect of silymarin administration to depressed patients with liver disease treated with H. perforatum.