Multiple cancer prevalence: a growing challenge in long-term survivorship.

OBJECTIVE: The present study was designed to estimate the number of and describe the pattern of disease among cancer survivors living with a history of multiple malignant tumors in the United States. METHODS: Incidence and follow-up data from the Surveillance, Epidemiology, and End Results program (1975-2001) were used to calculate the number of survivors with more than one malignant primary at January 1, 2002. U.S. prevalence counts were calculated by multiplying the age, sex, and race-specific prevalence proportions from the Surveillance, Epidemiology, and End Results program by the corresponding U.S. populations. RESULTS: We estimate that 756,467 people in the United States have been affected by cancer more than once between 1975 and 2001, representing almost 8% of the current cancer survivor population. Women whose first primary in that period was breast cancer represent 25% of survivors with multiple cancers, followed by men and women (15%) whose first primary was colorectal cancer and men (13%) whose first primary was prostate cancer. DISCUSSION: The findings in this report have important implications for public health practice. With individuals diagnosed with cancer living longer and the aging of the U.S. population, the number who will develop multiple malignancies is expected to increase. As a consequence, there is a growing need to promote effective cancer screening along with healthy life-styles among these at-risk populations if we are to ensure optimal physical and psychosocial well-being of these long-term cancer survivors and their families. Efforts to design and evaluate effective, efficient, and equitable approaches to surveillance for second malignancies will be critical in reducing the national burden of cancer.     

Altered insula response to taste stimuli in individuals recovered from restricting-type anorexia nervosa.

Anorexia nervosa (AN) is an illness characterized by aversion to ingestion of normally palatable foods. We examined whether there is a primary disturbance of taste processing and experience of pleasure using a sucrose/water task in conjunction with functional magnetic resonance imaging (fMRI). To avoid confounding effects of illness, 16 women recovered from restricting-type AN were compared to 16 control women (CW). We used a region of interest-based fMRI approach to test the idea that individuals with AN have differential neural activation in primary and secondary taste cortical regions after sucrose and water administration. Compared to CW, individuals recovered from AN showed a significantly lower neural activation of the insula, including the primary cortical taste region, and ventral and dorsal striatum to both sucrose and water. In addition, insular neural activity correlated with pleasantness ratings for sucrose in CW, but not in AN subjects. Altered taste processing may occur in AN, based on differences in activity in insular-striatal circuits. These data provide the first evidence that individuals with AN process taste stimuli differently than controls, based on differences in neural activation patterns.     

The effects of nickel and chromium on human keratinocytes: differences in viability, cell associated metal and IL-1alpha release.

This study was carried out to assess the effects of chromium and nickel upon isolated keratinocytes as an in vitro model of human skin. Keratinocytes were isolated from healthy volunteer skin samples of unknown metal sensitivity (n=10) and were compared with cells from patient biopsies of known metal sensitivity (n=7). Cells were dosed with a concentration range of nickel and chromium (0-10,000 microM) and cellular mitochondrial activity, viability, metal uptake and cytokine release were measured. Responses of primary versus passaged keratinocytes were also compared. Toxicity data from primary and passaged keratinocytes was statistically analysed by the non-linear Hill Plot model. Results showed that hexavalent chromium was significantly more cytotoxic, associated more with keratinocytes and induced a dose dependant release of IL-1alpha compared to nickel. Significant differences were observed between primary and passaged keratinocytes with regard to the toxicity of chromium and nickel and variation of response. No differences were observed in the cytotoxicity or cytokine release induced by chromium or nickel for the known sensitised biopsy patient samples (n=4) compared to patch test negative controls (n=3). The results from this study suggest human keratinocytes in vitro respond very differently to chromium and nickel.     

Melatonin attenuates tyrosine hydroxylase loss and hypolocomotion in MPTP-lesioned rats

Parkinson's disease is a chronic neurological disease characterized by dopaminergic neuron degeneration in the substantia nigra pars compacta. Melatonin is a powerful antioxidant agent secreted by the pineal gland which has numerous physiological functions and seems to exert an important neuroprotective effect. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model has been used to understand the pathophysiology of the disease because of its capacity to mimic biochemical and histological features observed in Parkinson's disease. This study investigated the effect of pretreatment with melatonin (50 mg/kg) on MPTP-lesioned animals 24 h and 7 days after neurotoxin infusion using the open-field test, two-way avoidance task and immunohistochemistry. Twenty-four hours after lesioning, the MPTP+vehicle group exhibited hypolocomotion and significant loss of tyrosine hydroxylase-immunoreactive cells, whereas no differences in these parameters were observed in lesioned animals receiving melatonin. Seven days after surgery, the MPTP-lesioned rats did not show hypolocomotion compared to control animals, while there was a significant dopaminergic neuronal loss. In the two-way avoidance task, MPTP-treated animals presented a cognitive deficit compared to the control groups and melatonin administration did not repair this defect. The present results suggest that melatonin reduces neuronal loss in the MPTP animal model of Parkinson's disease.     

Therapeutic significance of elevated tissue transglutaminase expression in pancreatic cancer.

PURPOSE: Tissue transglutaminase (TG2) is a multifunctional protein that is implicated in development of drug resistance and metastasis. Therefore, we examined therapeutic targeting of TG2 for inhibiting growth and metastasis of in vivo growing pancreatic ductal adenocarcinoma (PDAC) in nude mice. EXPERIMENTAL DESIGN: We implanted Panc-28 pancreatic cancer cells to induce orthotopic PDAC tumors in nude mice and determined the efficacy of liposomal TG2 small interfering RNA (siRNA) either alone or in combination with gemcitabine. RESULTS: We show that down-regulation of endogenous TG2 by siRNA could effectively block the growth of PDAC. Moreover, down-regulation of TG2 significantly enhanced the therapeutic efficacy of gemcitabine against PDAC and inhibited metastatic spread of the disease. The antitumor activity was related to inhibition of proliferation, angiogenesis, and Akt phosphorylation. CONCLUSION: siRNA-mediated down-regulation of TG2 represents a promising therapeutic approach for improved treatment of PDAC.     

Gefitinib induction of in vivo detectable signals by Bcl-2/Bcl-xL modulation of inositol trisphosphate receptor type 3

PURPOSE: To test whether epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) induce detectable signals in tumor cells and whether such signals may reveal alterations of the apoptotic program. EXPERIMENTAL DESIGN: Tumor cells were treated with gefitinib or erlotinib and tested for their ability to accumulate 99mTc-Sestamibi, a radiolabeled lipophilic cation that localizes in mitochondria. Then we tested whether Bcl-2 and Bcl-xL alter the pattern of drug-dependent tracer accumulation while reducing tumor cell sensitivity to EGFR TKIs. The mechanism underlying the pattern of tracer accumulation was elucidated. Finally, imaging studies were done in animal models and lung cancer patients before and after treatment with EGFR TKIs using single-photon emission computed tomography and 99mTc-Sestamibi. RESULTS: Gefitinib increases accumulation of 99mTc-Sestamibi in Bcl-2-overexpressing cells and enhances the physical interaction of phosphorylated Bcl-2 with inositol trisphosphate receptor type 3 (IP3R3). Consequently, a relative increase of cytosolic and mitochondrial calcium levels occurs. Similarly, lung cancer cells showed an increase of tracer uptake and an enhanced interaction of Bcl-xL with IP3R3 on exposure to erlotinib concentrations achievable in plasma. The occurrence of these interactions was associated with an enhanced EGFR TKI-induced apoptosis resistance. Posttreatment imaging studies in nude mice bearing control and Bcl-2-overexpressing breast carcinomas showed a high tumor uptake of the tracer whereas baseline studies failed to visualize tumors. Similarly, an enhancement of tracer uptake could be detected in patients with lung cancer treated with erlotinib. CONCLUSION: EGFR TKIs generate detectable signals by Bcl-2/Bcl-xL modulation of IP3R3 in tumor cells.     

Thymidine selectively enhances growth suppressive effects of camptothecin/irinotecan in MSI+ cells and tumors containing a mutation of MRE11

PURPOSE: DNA synthesis inhibitors and damaging agents are widely used in cancer therapy; however, sensitivity of tumors to such agents is highly variable. The response of tumor cells in culture to these agents is strongly influenced by the status of DNA damage response pathways. Here, we attempt to exploit the altered response of mismatch repair (MMR)-deficient colon cancer cells and tumors to camptothecin or irinotecan and thymidine by combining them to improve therapeutic response. EXPERIMENTAL DESIGN: A panel of colon cancer cell lines was assayed for response to camptothecin-thymidine combinations by measuring colony formation, cell cycle distribution, and senescence. Cell strains defective in p53, p21, or Mre11 were used in these assays to investigate the role of these cell cycle regulators. The in vivo antitumor response of xenografts to irinotecan and thymidine combinations was assessed in nude mice. RESULTS: Camptothecin-thymidine combinations suppress colony formation of MMR-deficient tumor cells 10- to 3,000-fold relative to that obtained with camptothecin alone and significantly reduce the concentrations of the agents required to induce late S/G(2) arrest and senescence. Sensitivity is not a direct result of MMR, p53, or p21 status. However MMR-deficient cell lines containing an intronic frameshift mutation of MRE11 show greatest sensitivity to these agents. Increased sensitivity to this combination is also evident in vivo as thymidine enhances irinotecan-induced growth suppression of MMR-deficient tumors carrying the MRE11 mutation in mouse xenografts. CONCLUSION: Irinotecan-thymidine combinations may be particularly effective when targeted to MSI+ tumors containing this readily detectable MRE11 mutation.     

The Growth Factor Midkine Antagonizes VEGF Signaling In Vitro and In Vivo

Midkine (MDK) is a heparin-binding growth factor involved in growth, survival, migration, and differentiation of various target cells and dysregulation of MDK signaling is implicated in a variety of inflammatory diseases and cancers. Although MDK has been reported to act on endothelial cells and to have proangiogenic effects, the exact role of MDK in angiogenesis is poorly defined. Here, we report that MDK is actually a modulator of angiogenesis and that it can abrogate the vascular endothelial growth factor A (VEGF-A)-induced proliferation of human microvascular endothelial cells in vitro through the downregulation of proangiogenic cytokines and through the upregulation of the antiangiogenic factor, tissue inhibitor of metalloproteinase 2. Phosphorylation of vascular endothelial growth factor receptor 2 (VEGFR-2) and of downstream signaling molecules, such as phosphatidylinositol-3-kinase and mitogen-activated protein kinases, is also impaired. Moreover, MDK downregulates VEGF-A-induced neovascularization and vascular permeability in vivo. We propose a model in which MDK is a new modulator of the VEGF-A-VEGFR-2 axis.