African-American inflammatory bowel disease in a Southern U.S. health center

Background

Inflammatory Bowel Diseases (IBD) remain significant health problems in the US and worldwide. IBD is most often associated with eastern European ancestry, and is less frequently reported in other populations of African origin e.g. African Americans ('AAs'). Whether AAs represent an important population with IBD in the US remains unclear since few studies have investigated IBD in communities with a majority representation of AA patients. The Louisiana State University Health Sciences Center in Shreveport (LSUHSC-S) is a tertiary care medical center, with a patient base composed of 58% AA and 39% Caucasian (W), ideal for evaluating racial (AA vs. W) as well and gender (M vs. F) influences on IBD.

Methods

In this retrospective study, we evaluated 951 visits to LSUHSC-S for IBD (between 2000 to 2008) using non-identified patient information based on ICD-9 medical record coding (Crohn's disease 'CD'-555.0- 555.9 and ulcerative colitis 'UC'-556.0-556.9).

Results

Overall, there were more cases of CD seen than UC. UC and CD affected similar ratios of AA and Caucasian males (M) and females (F) with a rank order of WF > WM > AAF > AAM. Interestingly, in CD, we found that annual visits per person was the highest in AA M (10.7 ± 1.7); significantly higher (* -p < 0.05) than in WM (6.3 ± 1.0). Further, in CD, the female to male (F: M) ratio in AA was significantly higher (*- p < 0.05) (1.9 ± 0.2) than in Caucasians (F:M = 1.3 ± 0.1) suggesting a female dominance in AACD; no differences were seen in UC F: M ratios.

Conclusion

Although Caucasians still represent the greatest fraction of IBD (~64%), AAs with IBD made up >1/3 (36.4%) of annual IBD cases from 2000-2008 at LSUHSC-S. Further studies on genetic and environments risks for IBD risk in AAs are needed to understand differences in presentation and progression in AAs and other 'non-traditional' populations.

Ligand-mediated selective targeting of adenovirus in metastatic breast cancer

Abstract #2126

The success of gene therapy relies on efficient and targeted delivery systems. Adenovirus vectors have a number of advantages for gene therapy. However, because of their lack of tumor tropism and their tendency to induce liver infection following systemic administration, they cannot be used for systemic attack on metastatic disease. Many solid tumors (e.g., colon, lung, and breast) and hematopoietic tumors over express the chemokine receptor CXCR4. CXCR4 belongs to the large superfamily of G protein-coupled receptors, and is known to participate in a number of biological processes including organogenesis, hematopoiesis, and immune response. Recent evidence has highlighted the role of CXCR4 in cancer, particularly in cancer metastasis due to dysregulation of the receptor leading to enhanced signaling. The present study addresses this issue by retargeting adenovirus to the breast cancer cells overexpressing CXCR4 receptor. We used sCAR-T4-CXCL12, a bispecific adaptor molecule with the ectodomain of CAR linked by the T4 fibritin trimerization motif to the human CXCR4 ligand CXCL12 (also known as SDF-1). The sCAR-T4-CXCL12 should therefore be useful in retargeting adenovirus vectors to CXCR4-positive metastases. Infectivity assays in the absence as well as presence of ligand were performed in human breast cancer MDA-MB-435 cells. Cells were infected with different titres of Ad-CMV-GFP-Luc with and without ligand. Forty-eight hours post-infection, cells were harvested and analysed for the GFP expression by fluorescent microscopy and flow cytometry. It was further interesting to observe the time-dependence of infectivity curve. For this purpose, MDA-MB-435 cells were incubated with optimum titre of Ad-CMV-GFP-Luc vector in the presence of CXCR4 targeting ligand at different time intervals. This was followed by expression analysis of GFP protein by fluorescent microscopy and flow cytometry. Quantification by flow cytometry demonstrated a dramatic 20- to 40-fold increase in the infectivity of MDA-MB-435 cells both in a dose-dependent and time-dependent manner using the sCAR-T4-CXCL12 targeted adenovirus compared to the untargeted vector. In this report, we show that sCAR-T4-CXCL12 can significantly redirect an adenoviral gene therapy vector to CXCR4-positive breast cancer cells in culture. This bispecific ligand should, therefore, be a powerful agent to retarget adenovirus vectors to tumor metastases. The future goal is to investigate the capacity of this agent to re-direct adenoviral vectors in vivo using breast cancer metastasis models.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2126.

Combination of oncolytic adenoviral therapy with chemotherapy for enhanced breast cancer cell killing

Abstract #2129

Oncolytic adenoviruses are emerging agents for treatment of cancer by tumor-restricted virus replication, cell lysis and virus spread. A promising oncolytic adenovirus agent, known as Ad5-24-RGD, harbors a 24-bp deletion in the E1A gene that abrogates the binding of E1A to the retinoblastoma tumor suppressor (Rb) and presents enhanced infectivity of primary cancer cells due to insertion of an Arg-Gly-Asp (RGD) motif into the fiber knob. Thus, Ad5-24-RGD has improved cancer cell infection efficiency due to expanded tropism toward alpha-v integrins. It also replicates selectively in cancer cells with Rb/p16 mutations. As with conventional therapy regimes, oncolytic virotherapy, by itself, has limited success in complete tumor eradication in both preclinical animal models and clinical studies. Combination of anticancer agents with different modes of action remains a mainstay in cancer treatment. We undertook one approach towards this end by combining oncolytic adenoviral therapy with chemotherapy. In this study, we investigated a combination treatment of breast cancer cells with Ad5-4-RGD and Docetaxel, a microtubule-stabilizing taxane that is being used in the clinic for the treatment of breast and prostate cancers and small cell carcinoma of the lung. Our results indicate a synergistic effect between Docetaxel and Ad5-24-RGD in breast cancer cell killing at a lower dose than either agent alone. These results suggest that viral replication was not inhibited by this chemotherapy treatment and that chemotherapy could reduce the amount of viral particles needed to help eradicate the tumor. Administration of lower viral loads would simultaneously improve safety and decrease immunogenicity of the vector. Likewise lower doses of chemotherapy agents would decrease toxicity and side effects. The inclusion of oncolytic adenoviruses into multimodal cancer treatment together with chemotherapy has a potential to become powerful therapeutic regimen.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2129.

Digestibility and utilization of pearl millet diets fed to finishing beef cattle

Pearl millet grain was blended with corn in 1:1 or 2:1 ratios in beef finishing diets fed in two metabolism and two feedlot trials. In Exp. 1, diets contained 1) 79.5% corn and 4.5% soybean meal (C-SBM), 2) 28% corn, 54.5% sorghum, and 1.5% soybean meal [GSC(2:1)], and 3) 28% corn and 56% pearl millet [PMC(2:1)]. In Exp. 2, diets contained 1) 81.5% corn and 3.5% soybean meal (C-SBM) or 2) 42.5% corn and 42.5% pearl millet [PMC(1:1)]. Diets fed to steers in metabolism trials in Exp. 1 and 2 had similar (P > .10) apparent digestion coefficients for OM, crude fiber, NDF, and ADF. However, ether extract digestibility was higher (P < .05) for C-SBM than for GSC(2:1) and PMC(2:1) in Exp. 1, and it was higher (P < .10) for C-SBM than for PMC(1:1) in Exp. 2. In both experiments CP digestibility was higher (P < .10) for C-SBM diets, and N retention was similar (P > .10) for diets within each experiment. In each experiment, TDN calculated from apparent digestion coefficients was converted to NEm and NEg. The TDN, NEm, and NEg were lower (P < .10) for GSC(2:1) and PMC(2:1) than for C-SBM in Exp. 1. Experimental diets were fed to steers (n = 45; 396 +/- 19 kg initial BW; 70-d ad libitum feeding) in Exp. 1 and to heifers (n = 30; 318 +/- 15 kg initial BW; 92-d ad libitum feeding) in Exp. 2. The ADG, empty body weight gain (EBG), and predicted EBG were not different (P > .10) for diets composed of the different grain sources. Feed DMI and DM per gain were higher (P < .05) for PMC(1:1) than for C-SBM in Exp. 2. Pearl millet supplied approximately 88% as much NEm and 85% as much NEg as the corn-SBM portion of diets having similar CP concentrations.

Effect of supplemental fish meal protein on site and extent of digestion in beef steers

The effects of supplemental fish meal on site and extent of digestion were determined using four steers equipped with ruminal, duodenal, and ileal cannulas. Fish meal was included in diets to supply 0 (0FM), 25 (25FM), 50 (50FM), or 75 (75FM) g of N daily above the CP requirement of a 400-kg steer gaining 1.2 kg/d. Total tract starch digestibility tended to be greatest for 25FM (95%), lowest for 0FM (90%), and intermediate for 50FM (94%) and 75FM (92%). Total tract N digestibility was greatest for 25FM, lowest for 0FM, and intermediate for 50FM and 75FM (cubic, P < .05). Total tract starch digestibility increased .46 percentage units for each unit increase in N digestibility (n = 16, P = .03). Ruminal starch digestibility was greatest for 25FM, intermediate for 50FM and 75FM, and lowest for 0FM (quadratic; P < .10). Starch flow to the duodenum was decreased for 25FM and 50FM vs 0FM and 75FM (quadratic, P < .10) and N flow to the duodenum was increased (linear, P < .01) by fish meal. Fish meal supplementation increased N digestibility (quadratic, P < .05) but had no effect (P > .10) on starch digestibility in the small intestine. Starch digestibility in the small intestine was not related to N flow to the duodenum; however, starch digestibility increased .9 percentage units for each percentage unit increase in N digestibility (n = 16, P = .02). Fish meal supplementation tended to increase total tract starch digestibility by increasing ruminal, but not small intestinal, digestibility.

Vitamin E supplementation and the retinopathy of prematurity

The effect of high-dosage E treatment (Rx) initiated at the stage of 3-plus active disease (target serum E levels, 5-6 mg/dl) was evaluated by a standardized scoring system of visual morbidity at the one to two year eye exam among infants cared for in the University of Pennsylvania Neonatal Complex (1976-1978). The incidence of legal blindness in both eyes or worse was decreased from 71 to 40% in E Rx (n = 10) as compared to non-E Rx (n = 14) infants, and the number of infants with minimal visual morbidity was increased. Pilot studies (1972-76; target serum E level, 1.5 and 3.0 mg/dl) of the prophylactic effect of E Rx from birth on showed a decrease in mean severity of acute stage disease and a decrease in sequelae at one to two years. A strikingly difference in visual morbidity following resolved low-grade ROP was seen when prestudy infants (1968-72) who were fed early iron supplements and given formulas with low E:PUFA ratios were compared to non-E Rx as well as to E Rx 1972-76 infants. Vitamin E seems to exert a beneficial effect at all stages of ROP, perhaps because of its broadly based regulatory role.