Recombinant human Tat-Hsp70-2: A tool for neuroprotection.

Human Hsp70-2 is a chaperone expressed mainly in the nervous system. Up to now, no study has reported on the recombinant expression of this important human chaperone. Herein, we describe the successful purification and characterization of recombinant human Hsp70-2 in Escherichia coli in both the full-length and the chimeric protein containing the protein transduction domain corresponding to the trans-activator of transcription (Tat) from HIV. Under optimized conditions, the Tat-Hsp70-2 was expressed in a soluble form and purified by two chromatographic steps (in a 3.6 mg/L fermentation broth yield): recombinant Tat-Hsp70-2 was folded and showed ATPase activity. In contrast, the full-length recombinant protein was only expressed in the form of inclusion bodies and thus was purified following a refolding procedure. The refolded Hsp70-2 protein was inactive and the protein conformation slightly altered as compared to the corresponding Tat-fused variant. The Tat-Hsp70-2 protein (100 nM), when added to human neuroblastoma SH-SY5Y cells subjected to hydrogen peroxide or 6-hydroxydopamine stress, partially protected from the deleterious effect of these treatments. This work describes an approach for the functional expression of human Tat-Hsp70-2 that provides sufficient material for detailed structure-function studies and for testing its ability to protect neuroblastoma cells from oxidative stress.

Langerhans cells facilitate epithelial DNA damage and squamous cell carcinoma.

Polyaromatic hydrocarbons (PAHs) are prevalent, potent carcinogens, and 7,12-dimethylbenz[a]anthracene (DMBA) is a model PAH widely used to study tumorigenesis. Mice lacking Langerhans cells (LCs), a signatory epidermal dendritic cell (DC), are protected from cutaneous chemical carcinogenesis, independent of T cell immunity. Investigation of the underlying mechanism revealed that LC-deficient skin was relatively resistant to DMBA-induced DNA damage. LCs efficiently metabolized DMBA to DMBA-trans-3,4-diol, an intermediate proximal to oncogenic Hras mutation, and DMBA-treated LC-deficient skin contained significantly fewer Hras mutations. Moreover, DMBA-trans-3,4-diol application bypassed tumor resistance in LC-deficient mice. Additionally, the genotoxic impact of DMBA on human keratinocytes was significantly increased by prior incubation with human-derived LC. Thus, tissue-associated DC can enhance chemical carcinogenesis via PAH metabolism, highlighting the complex relation between immune cells and carcinogenesis.

Risk of prostate cancer is not associated with levels of C-reactive protein and other commonly used markers of inflammation.

Most population-based studies studied the association between inflammation and prostate cancer (PCa) by assessing C-reactive protein (CRP). As these findings have shown inconsistent results, we aimed to also study different markers that have been commonly taken as indications of inflammation. A cohort based on four groups of men (n = 34,891), according to age at cohort entry (45, 55, 65 and 75 years), with measurements of glucose, triglycerides, total cholesterol, haptoglobin, albumin, hemoglobin and leukocytes were selected from the Apolipoprotein Mortality Risk database. A total of 17,937 men had measurements of non-high-sensitive CRP. Multivariate Cox proportional hazard models were used to analyze associations between inflammatory markers and PCa. A total of 49 of 12,063 men developed PCa in the age 45 group, whereas 207 of 9,940, 472 of 8,266 and 276 of 3,618 were diagnosed in the age 55, 65 and 75 groups, respectively. Mean follow-up time was 7.5 years (SD: 3.9). No markers showed an association with PCa risk, nor was there a trend by quartiles or an indication for different PCa risks by strata of hypercholesterolemia, hyperglycemia and hypertriglyceridemia status. The studied markers were not found to be associated with PCa risk. These null findings might be due to methodological issues; however, it is unlikely that strong and long-lasting associations between inflammation and PCa risk were missed as this was a large database with long follow-up. This indicates need for international consensus on appropriate inflammatory markers in the context of cancer that may be practically applied in large studies.

Low levels of apolipoprotein A-I and HDL are associated with risk of prostate cancer in the Swedish AMORIS study.

BACKGROUND: A detailed analysis of lipid profiles, using apolipoproteins, has not yet been conducted for prostate cancer (PCa). Since several etiological pathways have been proposed for PCa and lipids, we aimed to study this in a large Swedish cohort with 1,469 primary prostate cancers. METHODS: A cohort (n = 69,735) of all men aged 35 years or older, whose levels of triglycerides (TG) (mmol/L), total cholesterol (mmol/L), glucose (mmol/L), LDL (mmol/L), HDL (mmol/L), apoB (g/L), and apoA-I (g/L) were measured at baseline, was selected from the Apolipoprotein MOrtality RISk (AMORIS) database. About 2,008 men developed PCa. Multivariate Cox proportional hazard models were used to analyze associations between lipid components and PCa. RESULTS: ApoA-I and HDL were inversely associated with PCa risk (e.g., HR for HDL: 0.93 (95% CI: 0.81-1.07), 0.88 (0.76-1.01), 0.81 (0.70-0.94), for second, third, and fourth quartiles compared with the first quartile; with p for trend: 0.004; HR for apoA-I: 1.00 (0.88-1.13), 0.93 (0.82-1.05), 0.88 (0.77-0.99),), for second, third, and fourth quartiles compared with the first quartile; with p for trend: 0.022). ApoB, LDL, and non-HDL were not associated with PCa risk. CONCLUSIONS: Our results show that low HDL and ApoA-I as well as increased lipid ratios are related to increased PCa risk. Experimental studies are required to tease out the underlying biological mechanisms linking these lipid components to PCa.

Association between levels of C-reactive protein and leukocytes and cancer: three repeated measurements in the Swedish AMORIS study.

OBJECTIVE: To study levels of C-reactive protein (CRP) and leukocytes, as inflammatory markers, in the context of cancer risk. METHODS: From the Apolipoprotein MOrtality RISk (AMORIS) study, we selected 102,749 persons with one measurement and 9,273 persons with three repeated measurements of CRP and leukocytes. Multivariate Cox proportional hazards regression was applied to categories of CRP (<10, 10-15, 15-25, 25-50, >50 g/L) and quartiles of leukocytes. An inflammation-based predictive score (IPS) indicated whether someone had CRP levels of more than 10 mg/L combined with leukocytes of more than 10×10(9)/L. Reverse causality was assessed by excluding those with less than 3, 5, or 7 years of follow-up. To analyze repeated measurements of CRP and leukocytes, the repeated IPS (IPSr) was calculated by adding the IPS of each measurement. RESULTS: In the cohort with one measurement, there was a positive trend between CRP and risk of developing cancer, with the lowest category being the 0.99 (0.92-1.06), 1.28 (1.11-1.47), 1.27 (1.09-1.49), and 1.22 (1.01-1.48) for the second to fifth categories, respectively. This association disappeared when excluding those with follow-up of less than 3, 5, or 7 years. The association between leukocytes and cancer was slightly stronger. In the cohort with repeated measurements, the IPSr was strongly associated with cancer risk: 1.87 (1.33-2.63), 1.51 (0.56-4.06), and 4.46 (1.43-13.87) for IPSr=1, 2, and 3 compared with IPSr=0. The association remained after excluding those with follow-up of less than 1 year. CONCLUSIONS AND IMPACT: Our large, prospective cohort study adds evidence for a link between inflammatory markers and cancer risk by using repeated measurements and ascertaining reverse causality.

Immunoglobulin E and cancer: a meta-analysis and a large Swedish cohort study.

We quantified associations between IgE and cancer in a meta-analysis and cohort study. Pubmed and Embase were searched to extract information using predefined inclusion criteria. In the Apolipoprotein MOrtality RISk (AMORIS) database, 24,820 persons had IgE measurements. Multivariate Cox proportional hazard models were used to analyze associations between IgE and cancer. Twenty-seven studies were reviewed from which seven case-control studies were included for analysis. The pooled relative risk (random effects model) was 0.97 (95% CI 0.86-1.09). Cell types of tumor origin (mesenchymal tissue or cells of the nervous system, lymphatic or hematopoietic tissue, and epithelium) modified the effect. In the AMORIS cohort, 862 persons developed cancer. Hazard ratios comparing quartiles of IgE were similar to the findings in the meta-analysis (HR 0.87 (95% CI 0.72-1.06); 0.94 (0.78-1.14); 0.90 (0.74-1.10) for the 2nd, 3rd, and 4th quartile compared to the 1st quartile), but there was no pattern by tumor origin. Both studies showed a weak inverse association between IgE and cancer, but a pattern by cancer type was only seen in the meta-analysis. Our findings suggest the need for prospective studies studying IgE and cancer. Measurements of IgE should be combined with other information, e.g., bio-banked samples containing other key immunological discriminators.