Comparison of clinical and economic outcomes between high-intensity care and hospice care for the end-of-life melanoma patients

The intensity of care for patients at the end-of-life is increasing in recent years. Publications have focused on intensity of care for many cancers, but none on melanoma patients. Substantial gaps exist in knowledge about intensive care and its alternative, hospice care, among the advanced melanoma patients at the end of life. End-of-life care may be used in quite different patterns and induce both intended and unintended clinical and economic consequences. We used the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases to identify patients aged 65 years or older with metastatic melanoma who died between 2000 and 2007. We evaluated trends and associations between sociodemographic and health services characteristics and the use of hospice care, chemotherapy, surgery, and radiation therapy and costs. Survival, end-of-life costs, and incremental cost-effectiveness ratio were evaluated using propensity score methods. Costs were analyzed from the perspective of Medicare in 2009 dollars. In the first journal Article we found increasing use of surgery for patients with metastatic melanoma from 13% in 2000 to 30% in 2007 (P=0.03 for trend), no significant fluctuation in use of chemotherapy (P=0.43) or radiation therapy (P=0.46). Older patients were less likely to receive radiation therapy or chemotherapy. The use of hospice care increased from 61% in 2000 to 79% in 2007 (P =0.07 for trend). Enrollment in short-term (1-3 days) hospice care use increased, while long-term hospice care (≥ 4 days) remained stable. Patients living in the SEER Northeast and South regions were less likely to undergo surgery. Patients enrolled in long-term hospice care used significantly less chemotherapy, surgery and radiation therapy. In the second journal article, of 611 patients identified for this study, 358 (59%) received no hospice care after their diagnosis, 168 (27%) received 1 to 3 days of hospice care, and 85 (14%) received 4 or more days of hospice care. The median survival time was 181 days for patients with no hospice care, 196 days for patients enrolled in hospice for 1 to 3 days, and 300 days for patients enrolled for 4 or more days (log-rank test, P < 0.001). The estimated hazard ratios (HR) between 4 or more days hospice use and survival were similar within the original cohort Cox proportional hazard model (HR, 0.62; 95% CI, 0.49-0.78, P < 0.0001) and the propensity score-matched model (HR, 0.61; 95% CI, 0.47-0.78, P = 0.0001). Patients with ≥ 4 days of hospice care incurred lower end-of-life costs than the other two groups ($14,298 versus $19,380 for the 1- to 3-days hospice care, and $24,351 for patients with no hospice care; p < 0.0001). In conclusion, Surgery and hospice care use increased over the years of this study while the use of chemotherapy and radiation therapy remained consistent for patients diagnosed with metastatic melanoma. Patients diagnosed with advanced melanoma who enrolled in ≥ 4 days of hospice care experienced longer survival than those who had 1-3 days of hospice or no hospice care, and this longer overall survival was accompanied by lower end-of-life costs.^

Advanced Protein Modeling Method: Benchmarking and Applications in Computer-Aided Drug Discovery

Development of homology modeling methods will remain an area of active research. These methods aim to develop and model increasingly accurate three-dimensional structures of yet uncrystallized therapeutically relevant proteins e.g. Class A G-Protein Coupled Receptors. Incorporating protein flexibility is one way to achieve this goal. Here, I will discuss the enhancement and validation of the ligand-steered modeling, originally developed by Dr. Claudio Cavasotto, via cross modeling of the newly crystallized GPCR structures. This method uses known ligands and known experimental information to optimize relevant protein binding sites by incorporating protein flexibility. The ligand-steered models were able to model, reasonably reproduce binding sites and the co-crystallized native ligand poses of the β2 adrenergic and Adenosine 2A receptors using a single template structure. They also performed better than the choice of template, and crude models in a small scale high-throughput docking experiments and compound selectivity studies. Next, the application of this method to develop high-quality homology models of Cannabinoid Receptor 2, an emerging non-psychotic pain management target, is discussed. These models were validated by their ability to rationalize structure activity relationship data of two, inverse agonist and agonist, series of compounds. The method was also applied to improve the virtual screening performance of the β2 adrenergic crystal structure by optimizing the binding site using β2 specific compounds. These results show the feasibility of optimizing only the pharmacologically relevant protein binding sites and applicability to structure-based drug design projects.

Signal transduction of {\it HER-2\/}/{\it neu\/} receptor tyrosine kinase

Overexpression and/or amplification of HER2/neu is frequently detected in many human cancers. Activation of p185 tyrosine kinase can be achieved by point mutation, overexpression, deletion, and heterodimerization with other class I receptors. In this study I investigated the signal transduction pathways mediating the oncogenic signal of the point mutation-activated rat p185. I demonstrated that tyrosine phosphorylation of Shc and formation of Shc/Grb2 complex correlated to the transformation of NIH3T3 cells caused by the point mutation-activated rat HER2/neu. Furthermore, I observed that association with Shc was severely impaired by deletion of most of the major autophosphorylation sites of the point-mutated p185. The truncated p185 product, however, fully retained its ability to transform NIH3T3 cells, induce Shc tyrosine phosphorylation and Shc/Grb2 complex formation. These results suggest that tyrosine phosphorylation of Shc which allows formation of Shc/Grb2 complex may play an important role in cell transformation induced by the point mutation-activated p185, and that stable binding to mutant p185 may not be necessary for Shc to mediate this signaling pathway.^ Recent studies have suggested that formation of the complex containing Sos, Grb2 and Shc is important in coupling receptor tyrosine kinases to the Ras signaling pathway. To clarify the role of this trimer in the oncogenic signaling of the activated p185, I set out to interfere with the protein-protein interactions in Shc/Grb2/Sos complex by introducing Grb2 mutants with deletions in either amino- ($\Delta$N-Grb2) or carboxyl- ($\Delta$C-Grb2) terminal SH3 domains into B104-1-1 cells derived from NIH3T3 cells that express the point mutation-activated HER-2/neu. I found that the transformed phenotypes of the B104-1-1 cells were largely reversed by expression of the $\Delta$N-Grb2. The effect of the $\Delta$C-Grb2 on phenotypic reversion was much weaker. Biochemical analysis showed that the $\Delta$N-Grb2 was able to associate Shc but not the activated p185 nor Sos, while the $\Delta$C-Grb2 bound to Shc, the activated p185, and Sos. The p185-mediated Ras activation was severely inhibited by the $\Delta$N-Grb2 but not the $\Delta$C-Grb2. Taken together, these data demonstrate that interruption of the interaction between Shc and the endogenous Grb2 by the $\Delta$N-Grb2 is able to impair the oncogenic signaling of the mutation-activated p185, indicating that (i) the $\Delta$N-Grb2 functions as a strong dominant-negative mutant, (ii) Shc/Grb2/Sos pathway plays a major role in mediating the oncogenic signal of the mutation-activated p185. Unlike the $\Delta$N-Grb2, the $\Delta$C-Grb2 appears to be a relatively weak dominant-negative mutant, probably due to its ability to largely fulfill the biological functions of the wild-type Grb2. ^

Regulation of Bcl-2 expression by the product of the prostate apoptosis response gene -4, Par-4

Elevated expression levels of the bcl-2 proto-oncogene have been correlated with the appearance of androgen independence in prostate cancer. Although bcl-2 was first cloned as the t (14:18) translocation breakpoint from human follicular B cell lymphoma, the mechanism of overexpression of bcl-2 is largely undefined for advanced prostate cancer, there being no gross alterations in the gene structure. We investigated the role of the product of the prostate apoptosis response gene-4 (Par-4) and the product of the Wilms' tumor 1 gene (WT1) in the regulation of Bcl-2 expression in prostate cancer cell lines. We observed growth arrest and apoptosis, upon decreasing Bcl-2 protein and transcript in the high Bcl-2 expressing, androgen-independent prostate cancer cell lines, by all trans-retinoic acid treatment but this did not occur in the androgen-dependent cell lines expressing low levels of Bcl-2. Changes in localization of Par-4, and an induction in the expression of WT1 protein accompanied the decrease in the Bcl-2 protein and transcript following all trans-retinoic acid treatment, in the androgen-independent prostate cancer cell line. In stable clones expressing ectopic Par-4 we observed decreased Bcl-2 protein and transcript. This was accompanied by an induction in WT1 expression. Finally, we detected Par-4 and WT1 proteins binding to a previously identified WT1 binding site on the bcl-2 promoter both in vitro and in vivo leading to a decrease in transcription from the bcl-2 promoter. We conclude that Par-4 regulates Bcl-2 through a WT1 binding site on the bcl-2 promoter. ^