Citations

Exercise training elicits a metabolic and cardiovascular response that underlies fitness. The molecular mechanisms that orchestrate this adaptive response and secure the wide-ranging gains of a regimented exercise program are poorly understood. Formed through association of the Kir6.2 pore and the sulfonylurea receptor, the stress-responsive ATP-sensitive K+ channels (KATP channels), with their metabolic-sensing capability and broad tissue expression, are potential candidates for integrating the systemic adaptive response to repetitive exercise. Here, the responses of mice lacking functional Kir6.2-containing KATP channels (Kir6.2-KO) were compared with wild-type controls following a 28-day endurance swimming protocol. While chronic aquatic training resulted in lighter, leaner, and fitter wild-type animals, the Kir6.2-KO manifested less augmentation in exercise capacity and lacked metabolic improvement in body fat composition and glycemic handling with myocellular defects. Moreover, the repetitive stress of swimming unmasked a survival disadvantage in the Kir6.2-KO, associated with pathologic calcium-dependent structural damage in the heart and impaired cardiac performance. Thus, Kir6.2-containing KATP channel activity is required for attainment of the physiologic benefits of exercise training without injury.

Embryonic stem cells have the distinct potential for tissue regeneration, including cardiac repair. Their propensity for multilineage differentiation carries, however, the liability of neoplastic growth, impeding therapeutic application. Here, the tumorigenic threat associated with embryonic stem cell transplantation was suppressed by cardiac-restricted transgenic expression of the reprogramming cytokine TNF-α, enhancing the cardiogenic competence of recipient heart. The in vivo aptitude of TNF-α to promote cardiac differentiation was recapitulated in embryoid bodies in vitro. The procardiogenic action required an intact endoderm and was mediated by secreted cardio-inductive signals. Resolved TNF-α–induced endoderm-derived factors, combined in a cocktail, secured guided differentiation of embryonic stem cells in monolayers produce cardiac progenitors termed cardiopoietic cells. Characterized by a down-regulation of oncogenic markers, up-regulation, and nuclear translocation of cardiac transcription factors, this predetermined population yielded functional cardiomyocyte progeny. Recruited cardiopoietic cells delivered in infarcted hearts generated cardiomyocytes that proliferated into scar tissue, integrating with host myocardium for tumor-free repair. Thus, cardiopoietic programming establishes a strategy to hone stem cell pluripotency, offering a tumor-resistant approach for regeneration.

AbstractAdoptive T-cell transfer has achieved significant clinical success in advanced melanoma. However, therapeutic efficacy is limited by poor T-cell survival after adoptive transfer and by inefficient trafficking to tumor sites. Here, we report that intratumoral expression of the chemokine CCL21 enhances the efficacy of adoptive T-cell therapy in a mouse model of melanoma. Based on our novel observation that CCL21 is highly chemotactic for activated OT-1 T cells in vitro and down-regulates expression of CD62L, we hypothesized that tumor cell–mediated expression of this chemokine might recruit, and retain, adoptively transferred T cells to the sites of tumor growth. Mice bearing metastatic tumors stably transduced with CCL21 survived significantly longer following adoptive T-cell transfer than mice bearing non–CCL21-expressing tumors. However, although we could not detect increased trafficking of the adoptively transferred T cells to tumors, tumor-expressed CCL21 promoted the survival and cytotoxic activity of the adoptively transferred T cells and led to the priming of antitumor immunity following T-cell transfer. To translate these observations into a protocol of real clinical usefulness, we showed that adsorption of a retrovirus encoding CCL21 to OT-1 T cells before adoptive transfer increased the therapeutic efficacy of a subsequently administered dose of OT-1 T cells, resulting in cure of metastatic disease and the generation of immunologic memory in the majority of treated mice. These studies indicate a promising role for CCL21 in enhancing the therapeutic efficacy of adoptive T-cell therapy. [Cancer Res 2007;67(1):300–8]

Purpose Treatment with aromatase inhibitors decreases bone mineral density (BMD) and may increase the risk of fractures in postmenopausal women with early-stage breast cancer. The addition of zoledronic acid to adjuvant letrozole therapy may protect against bone loss. Patients and Methods Patients receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (LS) or total hip (TH) T score decreased to less than −2.0 or when a nontraumatic fracture occurred. The primary end point of this study was to compare the change in LS BMD at month 12 between the groups. Secondary end points included change in TH BMD and changes in serum bone turnover markers at month 12. Results The upfront and delayed groups each included 301 patients. At month 12, LS BMD was 4.4% higher in the upfront group than in the delayed group (95% CI, 3.7% to 5.0%; P < .0001), and TH BMD was 3.3% higher (95% CI, 2.8% to 3.8%; P < .0001). In the upfront group, mean serum N-telopeptide and bone-specific alkaline phosphatase concentrations decreased by 15.1% (P < .0001) and 8.8% (P = .0006), respectively, at month 12, whereas concentrations increased significantly in the delayed group by 19.9% (P = .013) and 24.3% (P < .0001), respectively. Conclusion With 1 year of follow-up, results of the primary end point of the Zometa-Femara Adjuvant Synergy Trial (Z-FAST) indicate that upfront zoledronic acid therapy prevents bone loss in the LS in postmenopausal women receiving adjuvant letrozole for early-stage breast cancer.

Abstract Learning Objectives After completing this course, the reader will be able to: Discuss the efficacy and safety of third-generation aromatase inhibitors as therapeutic options for patients with hormone-responsive breast cancer.Describe the impact of aromatase inhibitors on comorbidities that are common in this patient population.Identify the cost-effectiveness and quality-of-life effects of aromatase inhibitors. Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com Tamoxifen, once the gold standard adjuvant endocrine therapy for early breast cancer, is being challenged by third-generation aromatase inhibitors (AIs) that have demonstrated improved disease-free survival in a variety of adjuvant settings for early breast cancer. Tamoxifen and AIs have different safety profiles, which should allow physicians to begin to individualize treatment based on a patient's comorbidities and risk factors. Because of its properties as a partial estrogen agonist, tamoxifen has a positive effect on serum lipids and may confer a cardioprotective benefit, as well as a beneficial effect on bone health. However, tamoxifen increases the risk for endometrial cancer and cerebrovascular/thromboembolic events. In comparison, the major side effect of AIs is increased bone loss, which may heighten the risk for osteoporotic fractures and bone pain. Because of their superior efficacy and manageable side effects, AIs are a cost-effective alternative to tamoxifen, and clinical guidelines now embrace AIs as appropriate adjuvant therapy for hormone-sensitive early breast cancer. The anticipated results of ongoing trials will provide further insights into the long-term safety and application of AI therapy in the adjuvant setting.

Abstract Up to one fourth of women diagnosed with early breast cancer (EBC) have tumors that are human epidermal growth factor receptor 2 (HER-2) positive. This is associated with a high risk of relapse and death from meta-static disease. Trastuzumab, a monoclonal antibody directed against the extracellular domain of HER-2, improves survival and quality of life in women with HER-2-positive metastatic breast cancer receiving chemotherapy. Four major adjuvant trials—Herceptin® Adjuvant (HERA), National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31, North Central Cancer Treatment Group (NCCTG) N9831, and Breast Cancer International Research Group (BCIRG) 006—including between them &gt;13,000 women with HER-2-positive EBC, have investigated different adjuvant treatment approaches with trastuzumab. These trials have shown that trastuzumab reduces the 3-year risk of recurrence by about half in this population. The benefit was similar across the trials despite differences in patient populations, chemotherapy regimens, and sequencing of treatment. At a 2-year follow-up, interim results from the combined analysis of the NSABP B-31 and NCCTG N9831 trials showed a one third lower mortality for trastuzumab, and there was a trend toward an overall survival benefit in the HERA and BCIRG trials. A small Finnish trial, FinHer, investigating another regimen of trastuzumab, has also shown similarly positive results. Further follow-up of the major adjuvant trials will clarify the survival benefit for women receiving trastuzumab, as well as the optimal treatment duration (1 or 2 years). Notably, cardiac events in the trastuzumab-containing arms of these trials have remained within acceptable levels, with a slightly higher (0.6%–3.3%) incidence of congestive heart failure that mostly responded to treatment. Further follow-up will provide information on long-term cardiac safety. Overall, results from clinical trials are sufficiently compelling to consider 1 year of adjuvant trastuzumab treatment for women with HER-2-positive EBC based on the risk:benefit ratio demonstrated in these studies.

Purpose Aromatase inhibition depletes estrogen levels and may be associated with accelerated bone resorption. The National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) study MA.17B evaluated bone turnover markers and bone mineral density (BMD) in postmenopausal women randomly assigned to MA.17, a placebo-controlled trial of letrozole after standard adjuvant tamoxifen. Patients and Methods Eligible women had a baseline BMD T score of at least 2.0 in either the hip or L2-4 spine; all received calcium 500 mg and vitamin D 400 U daily. Percentage change in BMD (L2-L4 spine and hip) at 12 and 24 months, rate of osteoporosis, and change in markers of bone formation (serum bone alkaline phosphatase) and resorption (serum C-telopeptide and urine N-telopeptide) at 6, 12, and 24 months were compared. Results Two hundred twenty-six patients (122 letrozole, 104 placebo) were enrolled. Baseline characteristics were similar in the two groups, including BMD, median age of 60.7 years (81% < 70 years), and median follow-up of 1.6 years. At 24 months, patients receiving letrozole had a significant decrease in total hip BMD (−3.6% v −0.71%; P = .044) and lumbar spine BMD (−5.35% v −0.70%; P = .008). Letrozole increased urine N-telopeptide at 6, 12, and 24 months (P = .054, < .001, and .016, respectively). No patient went below the threshold for osteoporosis in total hip BMD, whereas at the L2-L4 (posteroanterior view), more women became osteoporotic by BMD while receiving letrozole (4.1% v 0%; P = .064). Conclusion After 5 years of adjuvant tamoxifen, subsequent letrozole causes a modest increase in bone resorption and reduction in bone mineral density in the spine and hip compared to placebo. Further follow-up is necessary to evaluate the long-term clinical implications of this difference.

Purpose To evaluate concordance between local and central laboratory HER2 testing results in patients from the North Central Cancer Treatment Group (NCCTG) N9831 adjuvant trial of trastuzumab. Patients and Methods NCCTG N9831 is a randomized, phase III clinical trial comparing three drug regimens: doxorubicin/cyclophosphamide followed by paclitaxel with trastuzumab added concurrently, sequentially, or not at all as adjuvant therapy for women with HER2-positive resected breast cancer. Originally, patients were eligible if their tumors were HER2 positive by either local laboratory immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH). A protocol modification in 2002 made central laboratory testing mandatory, with additional testing of discordant cases conducted by a reference laboratory. Concordance between local and central laboratory, and level of agreement between central and reference laboratory HER2 findings in discordant cases were examined. Results HER2 positivity was confirmed in 85.8% of 2,535 patients registered since March 2002. When local and central evaluation used the same methodology, concordance was 88.1% for FISH and 81.6% for a diagnostic test for presence of the HER2 protein. Among discordant cases examined at the reference laboratory, there was 94.3% agreement for IHC (0, 1+, 2+) and 95.2% agreement for FISH (not gene amplified). Conclusion There was a high degree of discordance between local and central testing for IHC and FISH, but a high degree of agreement between central and reference laboratories. These findings support the importance of using high-volume, experienced laboratories for HER2 testing to improve the process of selecting patients likely to benefit from trastuzumab therapy.