Effects of exercise on glucose tolerance and insulin resistance. Brief review and some preliminary results

With aging, glucose tolerance (GT) declines, plasma insulin concentration increases, and sensitivity to the action of insulin declines. Evidence is accumulating that this decline in glucose tolerance and insulin sensitivity can be prevented by regularly performed vigorous exercise. Preliminary results are presented in this paper showing that prolonged, strenuous and frequent exercise can also completely normalize GT by decreasing resistance to insulin in some patients with mild non insulin dependent diabetes mellitus (NIDDM) and in some individuals with impaired glucose tolerance (IGT). Exercise appears to be effective in normalizing GT only in patients who still have an adequate capacity to secrete insulin, and in whom insulin resistance is the major cause for abnormal GT. The amount of exercise required to normalize GT in such patients appears to be in the range of 25 to 35 km per week of running, or a comparable amount of another form of exercise, performed on a regular basis.

Proliferation of mitochondria in chronically stimulated rabbit skeletal muscle--transcription of mitochondrial genes and copy number of mitochondrial DNA

Mitochondrial proliferation was studied in chronically stimulated rabbit skeletal muscle over a period of 50 days. After this time, subunits of COX had increased about fourfold. Corresponding mRNAs, encoded on mitochondrial DNA as well as on nuclear genes, were unchanged when related to total tissue RNA, however, they were elevated two- to fivefold when the massive increase of ribosomes per unit mass of muscle was taken into account. The same was true for the mRNA encoding mitochondrial transcription factor A. Surprisingly, tissue levels of mtTFA protein were reduced about twofold, together with mitochondrial DNA. In conclusion, mitochondria are able to maintain high rates of mitochondrial transcription even in the presence of reduced mtTFA protein and mtDNA levels. Therefore, stimulated mtTFA gene expression accompanies stimulated mitochondrial transcription, as in other models, but it is not sufficient for an increase of mtDNA copy number and other, yet unknown, factors have to be postulated.

Germinal center B cell-like (GCB) and activated B cell-like (ABC) type of diffuse large B cell lymphoma (DLBCL): analysis of molecular predictors, signatures, cell cycle state and patient survival

Aiming to find key genes and events, we analyze a large data set on diffuse large B-cell lymphoma (DLBCL) gene-expression (248 patients, 12196 spots). Applying the loess normalization method on these raw data yields improved survival predictions, in particular for the clinical important group of patients with medium survival time. Furthermore, we identify a simplified prognosis predictor, which stratifies different risk groups similarly well as complex signatures. We identify specific, activated B cell-like (ABC) and germinal center B cell-like (GCB) distinguishing genes. These include early (e.g. CDKN3) and late (e.g. CDKN2C) cell cycle genes. Independently from previous classification by marker genes we confirm a clear binary class distinction between the ABC and GCB subgroups. An earlier suggested third entity is not supported. A key regulatory network, distinguishing marked over-expression in ABC from that in GCB, is built by: ASB13, BCL2, BCL6, BCL7A, CCND2, COL3A1, CTGF, FN1, FOXP1, IGHM, IRF4, LMO2, LRMP, MAPK10, MME, MYBL1, NEIL1 and SH3BP5. It predicts and supports the aggressive behaviour of the ABC subgroup. These results help to understand target interactions, improve subgroup diagnosis, risk prognosis as well as therapy in the ABC and GCB DLBCL subgroups.

Safety and efficacy of first-line irinotecan/fluoropymidine combinations in mCRC patients >65 years compared with those ≤65: The BICC-C study

4076

Background: BICC-C was a multicenter, randomized study that assessed efficacy & safety of irinotecan/fluoropyrimidines combinations in previously untreated mCRC patients. This study showed that FOLFIRI or FOLFIRI+bev were superior to their comparators (Proc ASCO 2006). We conducted a secondary analysis of efficacy & safety among all patients >65 years compared with those =65. Methods: Pts were randomized to: infusional FOLFIRI, modified bolus IFL (mIFL), or CapeIri; and concurrent celecoxib or placebo in a double-blind fashion. The protocol was amended in April 2004 and bevacizumab (bev) was added to the FOLFIRI and mIFL arms whereas CapeIri was discontinued. Period 1 (P1) and Period 2 (P2) designate subjects enrolled before or after the amendment. Results: Of 430 pts enrolled in P1, 150 were age >65 (median 71; range, 66–87) and 280 were = 65 (median, 56; 20–65). Of 117 pts in P2, 75 were >65 (median, 73; 66–84) and 42 were = 65 (median, 54; 32–65). No significant differences in efficacy or safety were observed between the two age groups. Results for P1: median progression free survival (PFS) was 6.5 and 6.7 mos; and median overall survival (OS) was 18.8 and 19.2 for >65 and =65, respectively. For the FOLFIRI regimen specifically median PFS was 7.5 and 7.6 mos, and median OS was 20.1 and 24.3 mos for >65 and =65, respectively. Results for P2: median PFS was 10.3 and 10.6 mos; and median OS was 19.8 and 23 mos for >65 and =65, respectively. For the FOLFIRI+bev regimen specifically median PFS was 11.1 and 11.2 mos for >65 and =65 respectively, and median OS has not yet been reached for either subgroup at time of analysis. Common grade = 3 AEs are listed below. Conclusions: Efficacy and safety for first line irinotecan/fluoropyrimidine regimens and for FOLFIRI & FOLFIRI+bev, specifically, did not differ for older and younger mCRC patients.

[Table: see text]

[Table: see text]

Updated results of BICC-C study comparing first-line irinotecan/fluoropymidine combinations with or without celecoxib in mCRC: Updated efficacy data

4027

Background: This multicenter, randomized study assessed efficacy & safety for irinotecan/fluoropyrimidines combinations in previously untreated mCRC. Methods: Pts were randomized to: infusional FOLFIRI, modified bolus IFL (mIFL), or CapeIri; and concurrent celecoxib or placebo in a double-blind fashion. The protocol was amended in April 2004: bevacizumab (bev) was added to the FOLFIRI and mIFL arms, whereas CapeIri was discontinued. Period 1 (P1) and Period 2 (P2) designate subjects enrolled before or after the amendment. Initial efficacy & safety analyses were reported at ASCO ’06. We now report follow-up of 46 months for P1 and 31 months for P2. Results: 430 pts were treated in P1 and 117 pts in P2. Baseline characteristics and post-study treatment were balanced. P1 results: Median progression free survival (PFS) was 7.6 mos for FOLFIRI; 5.9 mos for mIFL (p=0.004); and 5.8 mos for CapeIri (p=0.015). Median overall survival (OS) was 23.1 mos for FOLFIRI; 17.6 mos for mIFL (p=0.087); and 18.9 mos for CapeIri (p=0.27). One-year survival rate favored FOLFIRI (75%) compared to either mIFL (65%) or CapeIri (66%). Overall Response Rate (ORR) was 47% in FOLFIRI, 43% in mIFL, 39% in CapeIri (not significantly different). P2 results: Median PFS was 11.2 mos for FOLFIRI+bev and 8.3 mos for mIFL+bev (p=0.28). Median OS was not reached for FOLFIRI+bev but was 19.2 mos for mIFL+bev (p=0.007). One-year survival rate favored FOLFIRI+bev (87%) when compared to mIFL+bev (61%). ORR was 58% for FOLFIRI+bev and 54% for mIFL+bev (p=0.73). Common grade = 3 AEs are listed below. Celecoxib did not impact safety or efficacy. Conclusions: First line FOLFIRI or FOLFIRI+bev were superior to their comparators and show favorable results in survival and tolerability in untreated mCRC. Median survival for FOLFIRI+bev has not been reached.

[Table: see text]

No significant financial relationships to disclose.

Cortisol stimulates cell cycle activity in the cardiomyocyte of the sheep fetus

The role of cortisol in regulating cardiac myocyte growth in the near-term fetal sheep is unknown. We hypothesized that cortisol would suppress cardiomyocyte proliferation and stimulate cardiomyocyte binucleation and enlargement, signs of terminal differentiation. Cardiomyocyte dimensions and percent binucleation were determined in isolated cardiac myocytes from seven cortisol-treated and seven control fetuses; percentage of myocytes positive for Ki-67 was determined in an additional four cortisol-treated and four control hearts. Cortisol was infused into the circumflex coronary artery at subpressor rates (0.5 microg/kg.min, 7 d). Cortisol infusion had no hemodynamic effects, compared with controls or pretreatment conditions. Cortisol treatment increased heart weight (44.0 +/- 8.7 g vs. control, 34.9 +/- 9.1 g, P < 0.05). Heart to body weight ratio was greater in treated hearts, compared with controls (10.3 +/- 1.9 vs. 7.7 +/- 0.9 g/kg, P < 0.01). Ventricular myocyte length, width, and percent binucleation were not different between groups. The proportion of treated myocytes in the cell cycle staining for Ki-67 was higher in the left ventricle (5.5 +/- 0.1 vs. 2.7 +/- 0.4%, P < 0.005) and right ventricle (4.4 +/- 0.4 vs. 3.7 +/- 0.7%, P < 0.05), compared with controls. Wet weight to dry weight ratios from cortisol-treated and control hearts were not different. In conclusion, whereas cortisol infused into the fetal sheep heart has no effect on cardiomyocyte size or maturational state, it stimulates entry of cardiomyocytes in the cell cycle. Thus, increases in fetal heart mass associated with subpressor doses of cortisol are due to cardiomyocyte proliferation and not hypertrophic growth.

A randomized trial of first-line irinotecan/fluoropymidine combinations with or without celecoxib in metastatic colorectal cancer (BICC-C)

3506

Background: This multicenter, randomized study assessed efficacy & safety for 3 irinotecan/fluoropyrimidines combinations in previously untreated mCRC. In a 3 × 2 factorial design, we also assessed whether celecoxib added to chemotherapy (CT) improved CT efficacy and/or reduced toxicity. Methods: Pts were randomized to: FOLFIRI - irinotecan (I) 180 mg/m2, leucovorin (LV) 400 mg/m2, 5-FU bolus 400 mg/m2, & infusional 5-FU 2400 mg/m2 over 46 hours q 2 wks; modified IFL (m-IFL) - I 125 mg/m2, LV 20 mg/m2, & bolus 5-FU 500 mg/m2 wkly × 2, q 3 wks; or CapeIri - I 250 mg/m2 day 1 & capecitabine 1000 mg/m2 po BID × 14 days, q 3 wks. Pts were also randomized to concurrent celecoxib (400 mg po BID) or placebo in a double-blind fashion. Time to progression (TTP) was the primary endpoint. Results: 430 pts were enrolled from 2/03 to 4/04, prior to an amendment that added bevacizumab to CT arms. Baseline characteristics were balanced. TTP for FOLFIRI (median = 8.2 mos) was significantly better than for either m-IFL (6.0 mos; p = 0.01) or CapeIri (5.7 mos; p = 0.01). Overall survival (OS) also favored FOLFIRI (median = 23.1 mos) compared to either m-IFL (17.6 mos; p=0.10) or CapeIri (18.8 mos; p = 0.19). Common grade ≥ 3 toxicities are listed below. CapeIri had the highest rates of nausea, vomiting, diarrhea, dehydration & hand-foot syndrome, whereas FOLFIRI had lower rates. Among all 430 pts, median TTP did not differ for pts randomized to celecoxib compared to placebo (6.9 vs 6.9 mos; p=0.71). Median OS was also similar for celecoxib vs placebo (19.5 vs 18.8 mos; p=0.63). CT toxicities did not differ for celecoxib vs placebo. Rates for MI/stroke were 1.5% for celecoxib and 1.9% for placebo. Conclusions: First-line FOLFIRI offers a superior TTP when compared to m-IFL or CapeIri; OS & toxicity analyses also favored FOLFIRI. Celecoxib neither improved CT efficacy nor reduced CT toxicity. Updated survival data & data on pts enrolled after the addition of bevacuzimab will be presented.

[Table: see text]

[Table: see text]

Intraperitoneal pretarget radioimmunotherapy with CC49 fusion protein

PURPOSE

This study examined a pretarget radioimmunotherapy strategy for treatment of an i.p. tumor model (LS174T).

EXPERIMENTAL DESIGN

The strategy used regional administration (i.p.) of a novel targeting molecule composed of four CC49 anti-tumor-associated glycoprotein 72 (TAG-72) single-chain antibodies linked to streptavidin as a fusion protein (CC49 fusion protein); 24 hours later, a synthetic clearing agent was administered i.v. to produce hepatic clearance of unbound CC49 fusion protein/synthetic clearing agent complexes. Four hours later, a low molecular weight radiolabeled reagent composed of biotin conjugated to the chelating agent 7,10-tetra-azacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) complexed with (111)In-, (90)Y-, or (177)Lu-DOTA-biotin was injected.

RESULTS

Radiolocalization to tumor sites was superior with i.p. administration of radiolabeled DOTA-biotin as compared with i.v. administration. Imaging and biodistribution studies showed excellent tumor localization of radioactivity with (111)In- or (177)Lu-DOTA-biotin. Tumor localization of (111)In-DOTA-biotin was 43% ID/g and 44% ID/g at 4 and 24 hours with the highest normal tissue localization in the kidney with 6% ID/g at 48 and 72 hours. Therapy studies with (90)Y-DOTA-biotin at doses of 400 to 600 microCi or (177)Lu-DOTA-biotin at doses of 600 to 800 microCi produced significant prolongation of survival compared with controls (P = 0.03 and P < 0.01).

CONCLUSIONS

Pretarget radioimmunotherapy using regional administration of CC49 fusion protein and i.p. (90)Y- or (177)Lu-DOTA-biotin represents a successful therapeutic strategy in the LS174T i.p. tumor model and this strategy may be applicable to human trials in patients with i.p. ovarian cancer.

Adenovirus-mediated TA-p73β gene transfer increases chemosensitivity of human malignant melanomas

Malignant melanoma is the most aggressive form of skin cancer and has proven to be highly resistant to conventional chemotherapy. Intriguingly, the p53 tumor suppressor, a main mediator of chemoresistance in other tumor types, is rarely mutated in melanoma. However, we have previously shown that anti-apoptotic isoforms of p73 (deltaTA-p73), another member of the p53 family, are overexpressed in metastatic melanomas. DeltaTA-p73 can oppose the pro-apoptotic functions of p53 and full length p73, and thus it could contribute to melanoma chemoresistance. In this study, we use an efficient adenoviral-based gene transfer approach to introduce a transcriptionally active form of p73 (TA-p73beta) in melanoma cells, with the objective of overcoming drug resistance. Interestingly, TA-p73beta significantly sensitized 5 out of 7 aggressive melanoma cell lines to the standard therapeutic agents adriamycin and cisplatin. More importantly, TA-p73beta displayed a synergistic effect in vivo allowing adriamycin or cisplatin to block melanoma cell growth in mouse xenograft models (p < 0.05). In summary, our data show that Ad-mediated TA-p73beta gene expression can markedly sensitize a subset of melanoma cell lines to adriamycin and cisplatin in vitro and in vivo, suggesting a new chemosensitization strategy for malignant melanomas.

Comparison of Recombinant Human Thrombin and Plasma-Derived Human α-Thrombin

Bleeding can be a serious complication of surgery, and topical thrombin is widely used as an adjunct to hemostasis in diverse surgical settings. The potent hemostatic properties of thrombin derive from its ability to activate platelets directly to aggregate and adhere to damaged vessels and to catalyze the formation simultaneously of a fibrin matrix. Application of exogenous thrombin bypasses the physiological process of generating a thrombin burst by directly initiating the terminal reactions of blood clot formation. Currently, thrombin used to control surgical bleeding is primarily from bovine plasma, with a small percentage from human plasma. Human thrombin isolated from pooled plasma carries the risk of transmitting plasma-borne pathogens or prion diseases. The bovine preparations have been associated with protein and preparative contaminants that pose potential risks of developing cross-reacting antibodies. There is a need for a pure therapeutic preparation of human thrombin. Recombinant human thrombin (rhThrombin) has been efficiently produced from a prethrombin-1 precursor obtained from Chinese hamster ovary cell culture. This rhThrombin is substantially free of process-derived contaminants and has been characterized extensively in terms of composition, primary, secondary, and tertiary structure, enzymatic activity; and in vivo pharmacology. In vivo studies of topically applied rhThrombin have shown it is effective in achieving hemostasis in a rabbit liver excisional wound model. Clinical studies are ongoing to evaluate the safety and efficacy of rhThrombin as an adjunct to hemostasis in patients undergoing surgery.